Miniature gear pump with end face clearance automatic compensation function

Abstract

The invention discloses a miniature gear pump with an end face clearance automatic compensation function. The miniature gear pump comprises a pump body and a driver. The pump body comprises a lower shell, a long shaft pin, a short shaft pin, a sealing cover, a driving gear, a driven gear, a middle shell, a magnet, a connecting plate, a main shaft spring, a positioning pin and a pressure spring; the lower shell is provided with an 8-shaped groove, an oil inlet, an oil outlet and a positioning hole, the driving gear and the driven gear are meshed and installed in the 8-shaped groove, the middle shell is positioned through the positioning pin, the lower end face of the middle shell abuts against the upper end face of the gear, the compression spring is arranged between the middle shell and the sealing cover, the magnet is connected with the driving gear, and the driver is fixed to the connecting plate and can drive the magnet to rotate after being powered on. The gear pump is simplified in structure, the middle shell can float, end face gaps can be automatically compensated under high pressure, leakage is reduced, and the volume efficiency and the working stability are improved.

Description

Technical Field

[0001] This invention belongs to the field of micro gear pump technology, and particularly relates to a micro gear pump with automatic end face clearance compensation function. Background Technology

[0002] Gear pumps, which rely on the change and movement of working volume between the pump cylinder and meshing gears to achieve oil delivery or pressurization, are widely used in the industrial field. Their core structure usually consists of two gears, a pump body, and upper and lower shells (or front and rear covers) forming an oil suction chamber and an oil pressure chamber. During operation, the rotation of the gears increases the volume of the space on the disengaged side to form a vacuum for oil suction, while the volume of the space on the meshing side decreases to achieve oil pressure and oil delivery.

[0003] In the application of micro gear pumps, traditional structures have significant technical limitations: On the one hand, the pump body of traditional micro gear pumps is mostly composed of multiple parts such as upper shell, middle shell and lower shell connected together. Each shell mating surface needs to rely on sealing elements to prevent external leakage. In addition, a bushing needs to be installed to protect the gear shaft. This results in a large number of parts and a complex structure. The machining accuracy requirements for the shell parts are stringent, which not only increases the machining difficulty and time, but also makes the assembly steps cumbersome, ultimately driving up the production and manufacturing costs.

[0004] On the other hand, leakage of oil from the high-pressure chamber to the low-pressure chamber is an inherent problem during the operation of gear pumps. The leakage pathways mainly include the tooth flank clearance at the gear meshing line, the radial clearance between the pump body frame and the tooth tip, and the end face clearance between the two end faces of the gear and the side plates. Among these three types of clearances, the end face clearance has the largest leakage, and the leakage increases significantly with increasing operating pressure, severely affecting the pressure performance and volumetric efficiency of the gear pump. Traditional micro gear pumps lack automatic end face clearance compensation functions. To reduce end face leakage, the only solution is to further improve the machining accuracy of the gear end faces and side plates, which undoubtedly increases the machining difficulty and makes it difficult to balance leakage control and production economy. Summary of the Invention

[0005] The purpose of this invention is to provide a miniature gear pump with automatic end face clearance compensation function to solve the problems mentioned in the background art.

[0006] In view of this, the present invention provides a miniature gear pump with automatic end face clearance compensation function, characterized in that it includes a pump body and a driver, the pump body including a lower shell, a long shaft pin, a short shaft pin, a sealing cover, a driving gear, a driven gear, a middle shell, a magnet, a connecting plate, a main shaft spring, a positioning pin, and a clamping spring, the lower shell having an 8-shaped groove for accommodating the driving gear and the driven gear, and the lower shell having a groove extending to 8... The groove has an oil inlet and an oil outlet, and is provided with a first positioning hole, a second positioning hole, a third positioning hole, and a fourth positioning hole. The long shaft pin is inserted into the first positioning hole, and a main shaft spring is provided between its lower end and the bottom of the first positioning hole. The short shaft pin is inserted into the second positioning hole. The driving gear is mounted on the long shaft pin and can rotate relative to it. The driven gear is mounted on the short shaft pin and meshes with the driving gear. The middle shell is positioned in the third and fourth positioning holes by positioning pins. The lower end face of the middle shell abuts against the upper end faces of the driving gear and the driven gear. The top of the inner side of the sealing cover is provided with a centering groove that aligns with the first positioning hole. The upper end of the long shaft pin abuts against the centering groove. The compression spring is located between the middle shell and the sealing cover. The connecting plate is fixed to the lower shell by screws and presses the sealing cover. The magnet is inserted into the long shaft pin and connected to the driving gear. The driver is fixed to the connecting plate by screws and can drive the magnet to rotate after being powered on.

[0007] In a further embodiment of the present invention, the lower shell is further provided with a sealing groove, and a second extrusion part is provided on the lower horizontal end face of the sealing cover, and a sealing ring is provided between the second extrusion part and the sealing groove.

[0008] In a further embodiment of the present invention, the upper end of the long shaft pin is provided with a centering conical surface and the lower end is provided with an anti-rotation groove. The hook of the main shaft spring is installed in the anti-rotation groove, and the long shaft pin abuts against the centering groove of the sealing cover through the centering conical surface.

[0009] In a further embodiment of the present invention, the upper end of the short shaft pin is provided with an anti-rotation part, and the middle shell abuts against the anti-rotation part to restrict the rotation of the short shaft pin.

[0010] In a further embodiment of the present invention, a transmission shaft sleeve extends from the upper end of the drive gear, and a hexagonal key is provided on the outer surface of the transmission shaft sleeve. An isolation sleeve is injection molded inside the magnet, and a hexagonal keyway is provided on the isolation sleeve. The magnet is connected to the drive gear through the cooperation of the hexagonal keyway and the hexagonal key.

[0011] In a further embodiment of the present invention, the magnet is provided with a corrosion-resistant metal protective shell, and the magnet can rotate relative to the long shaft pin.

[0012] In a further embodiment of the present invention, a first compression part is provided on the inner side of the annular step in the middle of the sealing cover, and a compression spring is disposed between the middle shell and the first compression part.

[0013] In a further embodiment of the present invention, a sealing groove is provided on the lower end face of the driver housing, and a sealing ring is provided between the sealing groove and the upper end of the connecting plate.

[0014] In a further embodiment of the present invention, a positioning hole is provided on the middle shell, and a positioning pin passes through the positioning hole and is inserted into the third positioning hole and the fourth positioning hole to realize the positioning of the middle shell.

[0015] In a further embodiment of the present invention, the tooth profiles of the lower end face of the middle shell, the driving gear and the driven gear, and the inner wall of the figure-eight groove of the lower shell form an oil suction chamber, which is connected to the oil inlet. In the area enclosed by the lower shell and the sealing cover, the space other than the oil suction chamber is a pressure chamber, which is connected to the oil outlet.

[0016] The beneficial effects of this invention are: This invention optimizes the pump body structure design, reducing the number of pump casings and sealing surfaces in traditional micro gear pumps, while eliminating the need for additional bushing components, resulting in a simpler overall structure. This structural simplification not only lowers the precision requirements for core components such as the casing and gears, reducing machining time and difficulty, but also simplifies assembly steps, effectively reducing manufacturing and assembly costs, and enhancing the product's economic viability and market competitiveness.

[0017] A floating middle shell structure is incorporated. Combined with the pressure spring and the pressure of the oil chamber, when the gear pump operates under high pressure and high load, the high-pressure oil in the oil chamber exerts downward pressure on the upper end of the middle shell, pushing it to fit more tightly against the lower shell. This automatically reduces the end-face clearance between the gear end face and the middle and lower shells. This automatic compensation function significantly reduces end-face leakage under high-pressure conditions, effectively improving the gear pump's working pressure and volumetric efficiency, meeting the demands of high-pressure, high-efficiency applications.

[0018] A sealing ring is installed between the sealing cover and the lower housing, and another sealing ring is installed between the actuator and the connecting plate, creating a multi-layered and reliable sealing structure. The elastic rubber sealing rings are compressed after assembly, effectively filling the tiny gaps between components and preventing oil leakage and external liquids from entering the actuator. This ensures the stable operation of the gear pump, avoids performance degradation or actuator damage caused by leakage, and extends the product's service life.

[0019] On the one hand, the long shaft pin, through the flexible connection of the main shaft spring and the anti-rotation groove limit, can not only ensure the stable contact between the long shaft pin and the centering groove of the sealing cover, but also limit the rotation of the long shaft pin and avoid transmission deviation. On the other hand, the drive gear and the magnet are fixedly engaged by the hexagonal key and hexagonal keyway in a circumferential manner, ensuring that the magnet can drive the drive gear to rotate synchronously and stably when it rotates, reducing transmission gap and energy loss, and improving the stability and transmission reliability of the overall structure. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a gear pump. Figure 2 This is an exploded view of a gear pump; Figure 3 This is a cross-sectional view of a gear pump; Figure 4 This is a schematic diagram of the installation of the inner casing of a gear pump; Figure 5 This is a schematic diagram of the lower casing structure of a gear pump; Figure 6 This is a half-sectional view of the lower casing of the gear pump; Figure 7 This is a schematic diagram of the long shaft pin structure of a gear pump; Figure 8 This is a schematic diagram of the short shaft pin structure of a gear pump; Figure 9 This is a schematic diagram of the gear pump sealing cover structure; Figure 10 This is a schematic diagram of the inner shell structure of a gear pump; Figure 11 This is a schematic diagram of the magnet structure of a gear pump. Detailed Implementation

[0021] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0022] In the description of this application, it should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. For ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0023] It should be noted that the terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and are not limited in number; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0024] It should be noted that in the description of this application, the directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" 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 application and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this application. The directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0025] It should be noted that, in this application, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Furthermore, it should be noted that the scope of the methods and apparatuses in the embodiments of this application is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

[0026] This embodiment provides a miniature gear pump with automatic end-face clearance compensation function, including a pump body 1 and a driver 15. These two components are the core of the gear pump. The pump body 1 undertakes the core functions of oil containment, sealing, and transportation, while the driver 15 provides stable power for the operation of the pump body 1. Together, they ensure the efficient operation of the gear pump. The pump body 1 includes a lower shell 2, a long shaft pin 3, a short shaft pin 4, a sealing cover 5, a driving gear 6, a driven gear 7, a middle shell 8, a magnet 9, a connecting plate 10, a main shaft spring 11, a positioning pin 12, and a clamping spring 13. These components form a complete transmission and sealing system through precise assembly, ensuring structural stability and functional reliability. The lower shell 2 serves as the basic support component of the pump body 1. Its top is provided with a figure-eight groove 21 that perfectly matches the contours of the driving gear 6 and the driven gear 7. This figure-eight groove 21 can completely accommodate the driving gear 6 and the driven gear 7, providing interference-free space for the meshing rotation of the two gears. Simultaneously, an oil inlet 22 and an oil outlet 23 are provided through the lower shell 2, extending from the outside of the lower shell 2 to the corresponding areas of the figure-eight groove 21, respectively, to realize the input and output of oil. Furthermore, the lower shell 2 also has a first positioning hole 24 for assembling the long shaft pin 3, a second positioning hole 25 for assembling the short shaft pin 4, and a third positioning hole 26 and a fourth positioning hole 27 for positioning the middle shell 8. The positional accuracy of each positioning hole strictly matches the corresponding component, ensuring the coaxiality and positional accuracy of each component after assembly. The long shaft pin 3 is vertically inserted into the first positioning hole 24. A main shaft spring 11 is provided between its lower end and the bottom of the first positioning hole 24. The main shaft spring 11 can apply an upward elastic force to the long shaft pin 3, so that the long shaft pin 3 always maintains an upward preloaded state, preventing axial loosening of the long shaft pin 3 during operation and improving transmission stability. The short shaft pin 4 is vertically inserted into the second positioning hole 25. Its outer wall is tightly fitted with the inner wall of the second positioning hole 25, providing stable rotational support for the driven gear 7. The driving gear 6 is mounted on the long shaft pin 3, with a reasonable gap reserved between its inner wall and the outer wall of the long shaft pin 3 to ensure that the driving gear 6 can rotate flexibly around the long shaft pin 3; the driven gear 7 is mounted on the short shaft pin 4, with a rotational gap also reserved between its inner wall and the outer wall of the short shaft pin 4, and the teeth of the driven gear 7 precisely mesh with the teeth of the driving gear 6 to achieve synchronous power transmission. The meshing gap between the two is strictly controlled to reduce oil leakage in the tooth side gap.The middle shell 8 is positioned in the third positioning hole 26 and the fourth positioning hole 27 by positioning pins 12. The positioning pins 12 can limit the horizontal displacement of the middle shell 8 and prevent the middle shell 8 from shifting laterally under pressure. At the same time, the lower end face of the middle shell 8 is tightly pressed against the upper end face of the driving gear 6 and the driven gear 7 to form an end face sealing structure, which can effectively prevent oil leakage from the gear end face upward. This pressing fit of the middle shell 8 also provides a structural basis for subsequent automatic compensation of end face gap. The sealing cover 5 is fastened to the upper part of the lower shell 2. The center of its inner top is provided with a centering groove 51 that is vertically aligned with the first positioning hole 24. The upper end of the long shaft pin 3 abuts against the centering groove 51. The cooperation between the centering groove 51 and the upper end of the long shaft pin 3 can radially limit the upper end of the long shaft pin 3, prevent the long shaft pin 3 from radially running during high-speed rotation, and further improve the rotational stability of the long shaft pin 3. The compression spring 13 is disposed between the middle shell 8 and the sealing cover 5. When compressed, the compression spring 13 applies downward elastic pressure to the middle shell 8, ensuring that the middle shell 8 maintains a constant downward preload. This ensures a tight fit between the lower end face of the middle shell 8 and the upper end face of the gear, reducing end face gap and initial leakage in the initial state. The connecting plate 10 is fixed to the top end face of the lower shell 2 by multiple evenly distributed screws. The tightening torque of the screws is strictly controlled to ensure that the connecting plate 10 applies a uniform clamping force to the sealing cover 5, forming a stable sealing fit between the sealing cover 5 and the lower shell 2. This prevents external impurities from entering the pump body 1 and also prevents internal oil leakage from the pump body 1. The magnet 9 is vertically inserted into the long shaft pin 3, with a rotational gap reserved between its inner wall and the outer wall of the long shaft pin 3. The lower end of the magnet 9 is fixedly connected to the upper end of the drive gear 6, ensuring that the magnet 9 rotates synchronously with the drive gear 6, thus transmitting power from the driver 15 to the drive gear 6. The driver 15 is fixed to the top of the connecting plate 10 with screws. The driver 15 uses an electromagnetic drive principle; when energized, it generates a continuously changing rotating magnetic field. This rotating magnetic field produces an electromagnetic driving force on the magnet 9, causing it to rotate around the axis of the long shaft pin 3. The fixed structure between the driver 15 and the connecting plate 10 is stable, preventing vibration and deviation of the driver 15 during operation and ensuring the stability of power transmission.

[0027] In this invention, furthermore, the top end face of the lower shell 2 is provided with an annular sealing groove 28, which surrounds the figure-eight groove 21, and its cross-sectional dimensions are adapted to the cross-sectional dimensions of the sealing ring 14; the lower horizontal end face of the sealing cover 5 is provided with a second extrusion part 53 that is vertically aligned with the sealing groove 28, and the second extrusion part 53 is an annular protrusion structure integrally formed on the lower end face of the sealing cover 5; during assembly, the sealing ring 14 is placed in the sealing groove 28, and after the sealing cover 5 is fastened, the second extrusion part 53 just presses against the top of the sealing ring 14, so that the sealing ring 14 is compressed and deformed between the sealing groove 28 and the second extrusion part 53. The elastic deformation of the sealing ring 14 can fill the tiny gap between the sealing cover 5 and the lower shell 2, forming a reliable radial seal, effectively preventing the high-pressure oil inside the pump body 1 from leaking outward from the mating surface of the sealing cover 5 and the lower shell 2, while preventing external dust, water vapor and other impurities from entering the pump body 1. The internal contaminated oil significantly improves the sealing reliability and service life of pump body 1.

[0028] In this invention, the upper end of the long shaft pin 3 is integrally formed with a centering conical surface 31. The taper of the centering conical surface 31 is perfectly matched with the taper of the centering groove 51 of the sealing cover 5. The long shaft pin 3 abuts against the centering groove 51 of the sealing cover 5 through the centering conical surface 31. The structure of the conical surface fit can realize the automatic centering of the long shaft pin 3. Even if there is a slight deviation during the assembly process, the fit between the centering conical surface 31 and the centering groove 51 can automatically correct the axial position of the long shaft pin 3, ensuring that the axis of the long shaft pin 3 coincides with the axis of the centering groove 51 of the sealing cover 5, avoiding radial runout when the long shaft pin 3 rotates at high speed, and reducing friction and wear between the long shaft pin 3 and the drive gear 6. The lower end of the long shaft pin 3 has an annular anti-rotation groove 32. The upper end hook of the main shaft spring 11 is embedded and installed in the anti-rotation groove 32. This structure can restrict the long shaft pin 3. Rotating around its own axis prevents the long shaft pin 3 from rotating under the reaction force of the drive gear 6, ensuring that the long shaft pin 3 always remains fixed, providing stable rotational support for the drive gear 6, and further improving transmission stability.

[0029] In this invention, the upper end of the short shaft pin 4 is integrally formed with an anti-rotation part 41, which is a planar structure formed by milling the outer wall of the upper end of the short shaft pin 4. The inner wall of the middle shell 8 is closely fitted with this planar structure. After the middle shell 8 is fixed by the positioning pin 12, its inner wall forms a circumferential limit on the anti-rotation part 41, which can effectively restrict the short shaft pin 4 from rotating around its own axis, avoid the short shaft pin 4 from rotating under the rotational reaction force of the driven gear 7, ensure that the short shaft pin 4 always remains fixed, provide stable rotational support for the driven gear 7, prevent the driven gear 7 from shifting its axis due to the rotation of the short shaft pin 4, ensure the meshing accuracy of the driven gear 7 and the driving gear 6, reduce tooth surface friction and wear, and reduce the risk of oil leakage caused by meshing misalignment.

[0030] In this invention, further, a cylindrical transmission sleeve 61 extends integrally from the upper end face of the drive gear 6. The transmission sleeve 61 is coaxially arranged with the drive gear 6, and its outer wall is integrally formed with a hexagonal key 62 extending axially. The cross-section of the hexagonal key 62 is a standard hexagonal structure. The interior of the magnet 9 is formed by injection molding with a cylindrical isolation sleeve 92. The isolation sleeve 92 is coaxially arranged with the magnet 9, and the inner wall of the isolation sleeve 92 has a hexagonal keyway 921 that matches the cross-section of the hexagonal key 62. During assembly, the transmission sleeve 61 of the drive gear 6 is inserted into the isolation sleeve 92 of the magnet 9, and the hexagonal key 62 is precisely embedded in the hexagonal keyway 921. Through the circumferential fit between the hexagonal key 62 and the hexagonal keyway 921, the magnet 9 and the drive gear 6 are circumferentially fixed, ensuring that when the magnet 9 rotates, the force of the hexagonal key 62 and the hexagonal keyway 921 synchronously drives the drive gear 6. Rotation provides high transmission efficiency and eliminates slippage, preventing energy loss during power transmission. Simultaneously, the isolation sleeve 92 separates the magnet 9 from the drive gear 6, preventing direct contact and frictional wear, thus extending their service life.

[0031] Furthermore, in this invention, the magnet 9 is further encased in a corrosion-resistant metal protective shell 91. The corrosion-resistant metal protective shell 91 is made of corrosion-resistant materials such as stainless steel, and its inner wall is tightly fitted to the outer wall of the magnet 9. This effectively protects the magnet 9 from corrosion by the oil inside the pump body 1, preventing the magnet 9 from weakening or failing due to corrosion, and ensuring the stable driving performance of the magnet 9. At the same time, the corrosion-resistant metal protective shell 91 also enhances the structural strength of the magnet 9, preventing the magnet 9 from breaking under high-speed rotation or pressure. In addition, the magnet 9 is fitted onto the long shaft pin 3 through an isolation sleeve 92. A reasonable gap is reserved between the inner wall of the isolation sleeve 92 and the outer wall of the long shaft pin 3, ensuring that the magnet 9 can rotate flexibly around the long shaft pin 3, reducing the frictional resistance during the rotation of the magnet 9, and reducing energy loss.

[0032] In this invention, further, an annular first extrusion part 52 is integrally formed on the inner side of the annular step in the middle of the sealing cover 5, and the lower end surface of the first extrusion part 52 is a horizontal plane; the upper end of the compression spring 13 abuts against the lower end surface of the first extrusion part 52, and the lower end abuts against the upper end surface of the middle shell 8, that is, the compression spring 13 is disposed between the middle shell 8 and the first extrusion part 52. The first extrusion part 52 provides a stable upper end support point for the compression spring 13, ensuring that the force of the compression spring 13 can be evenly transmitted to the upper end surface of the middle shell 8; at the same time, the position of the first extrusion part 52 corresponds to the force center of the middle shell 8, so that the pressure of the compression spring 13 on the middle shell 8 is evenly distributed, avoiding the middle shell 8 from tilting due to uneven force, ensuring that the lower end surface of the middle shell 8 is evenly fitted with the upper end surface of the driving gear 6 and the driven gear 7, further reducing the end face gap and reducing the amount of oil leakage.

[0033] In this invention, the lower end face of the driver 15 housing is provided with an annular sealing groove 151, which surrounds the output end of the driver 15. During assembly, the sealing ring 152 is placed in the sealing groove 151. After the driver 15 is fixed to the connecting plate 10, the upper end face of the connecting plate 10 presses against the lower end face of the sealing ring 152, causing the sealing ring 152 to be compressed and deformed between the sealing groove 151 and the connecting plate 10. The elastic deformation of the sealing ring 152 can fill the gap between the driver 15 housing and the connecting plate 10, forming a reliable axial seal. This effectively prevents oil inside the pump body 1 or dust, water vapor and other impurities from entering the driver 15, avoiding damage to the motor, wiring and other components inside the driver 15 due to oil immersion or impurity contamination, and significantly improving the working stability and service life of the driver 15.

[0034] In this invention, the upper end face of the middle shell 8 is provided with two positioning holes 81 that are vertically aligned with the third positioning hole 26 and the fourth positioning hole 27. The diameter of the positioning holes 81 is adapted to the diameter of the positioning pin 12. During assembly, the lower end of the positioning pin 12 passes through the positioning holes 81 of the middle shell 8 in sequence and is then inserted into the third positioning hole 26 and the fourth positioning hole 27 of the lower shell 2. The positioning pin 12 and the positioning holes 81, the third positioning hole 26, and the fourth positioning hole 27 are all transition fits. This multi-positioning point structure can accurately limit the horizontal and rotational displacement of the middle shell 8, ensuring that the position of the middle shell 8 always corresponds to the position of the figure-eight groove 21, the driving gear 6, and the driven gear 7 of the lower shell 2. This prevents the middle shell 8 from shifting due to pressure or vibration, ensures the fitting accuracy between the lower end face of the middle shell 8 and the upper end face of the gear, and provides structural protection for the stable realization of the automatic end face gap compensation function.

[0035] In this invention, furthermore, the lower end face of the middle shell 8, the tooth profile of the driving gear 6, the tooth profile of the driven gear 7, and the inner wall of the figure-eight groove 21 of the lower shell 2 together form a sealed oil suction chamber 16. The volume of the oil suction chamber 16 changes periodically with the meshing rotation of the gears. The oil suction chamber 16 is connected to an external oil source through the oil inlet 22 of the lower shell 2. When the volume of the oil suction chamber 16 increases, external oil can be sucked into the oil suction chamber 16 through the oil inlet 22. At the same time, the top end face of the lower shell 2 and the lower end face of the sealing cover 5 form a large sealed area. The space in this area other than the oil suction chamber 16 is the oil pressure chamber 17. The oil pressure chamber 17 is connected to an external oil-using device through the oil outlet 23 of the lower shell 2. When the gear rotates, causing the volume of the oil suction chamber 16 to decrease and the volume of the oil pressure chamber 17 to increase, the oil suction chamber 16... The oil inside is squeezed into the oil pressure chamber 17. Under pressure, the oil in the oil pressure chamber 17 is transported to the external oil-using equipment through the oil outlet 23, realizing the pressurization and transportation of the oil. The independent setting of the oil suction chamber 16 and the oil pressure chamber 17 ensures that the oil does not flow between each other during the suction and pressurization process, which significantly improves the volumetric efficiency of the gear pump.

[0036] The working process of this gear pump is as follows: Initial preparation stage: After assembly, the main shaft spring 11 is in a naturally extended state, applying an upward elastic force to the long shaft pin 3, so that the centering cone surface 31 at the upper end of the long shaft pin 3 tightly abuts against the centering groove 51 of the sealing cover 5, realizing the axial pre-tightening and radial alignment of the long shaft pin 3, and preventing radial runout during subsequent operation; the compression spring 13 is in a compressed state, applying a downward elastic pressure to the middle shell 8, so that the lower end face of the middle shell 8 tightly fits against the upper end face of the driving gear 6 and the driven gear 7, forming a small end face gap in the initial state, reducing oil leakage from the source; the sealing ring 14 is compressed between the second extrusion part 53 of the sealing cover 5 and the sealing groove 28 of the lower shell 2, and the sealing ring 152 is compressed between the sealing groove 151 of the driver 15 and the connecting plate 10, constructing a multi-seal system, respectively blocking the channels for oil leakage from the pump body 1 and external impurities to enter the driver 15.

[0037] Power transmission and gear rotation stage: When the driver 15 is energized, its internal coil generates a continuously changing rotating magnetic field, which generates a circumferential electromagnetic driving force on the magnet 9 inside the pump body 1. Since the magnet 9 is circumferentially fixed by the hexagonal keyway 921 of the isolation sleeve 92 and the hexagonal key 62 of the drive gear 6 transmission shaft sleeve 61, when the magnet 9 rotates around the axis of the long shaft pin 3, it will synchronously drive the drive gear 6 to rotate around the long shaft pin 3. The drive gear 6 and the driven gear 7 mesh precisely, thereby driving the driven gear 7 to rotate synchronously in the opposite direction around the short shaft pin 4. During this process, the anti-rotation part 41 at the upper end of the short shaft pin 4 fits against the inner wall of the middle shell 8, and the middle shell 8 is fixed by the positioning pin 12, effectively restricting the short shaft pin 4 from rotating. The anti-rotation groove 32 at the lower end of the long shaft pin 3 cooperates with the hook of the main shaft spring 11 to restrict the long shaft pin 3 from rotating, ensuring the stable rotation of the two gears.

[0038] Oil intake stage: As the driving gear 6 and driven gear 7 continue to rotate, the volume of the space on the side where the two gears disengage (corresponding to the area of ​​the oil suction chamber 16 enclosed by the figure-eight groove 21 of the lower shell 2 and the middle shell 8) gradually increases, forming a partial vacuum. Under the pressure difference between the external atmospheric pressure and the vacuum in the oil suction chamber 16, external oil is continuously drawn into the oil suction chamber 16 through the oil inlet 22 of the lower shell 2 until the gears in this area completely disengage, the volume of the oil suction chamber 16 reaches its maximum, and the oil suction process ends.

[0039] Oil pressurization and delivery stage: As the gears continue to rotate, the oil drawn into the suction chamber 16 moves with the gear teeth to the meshing side of the two gears (corresponding to the area of ​​the pressure chamber 17 enclosed by the lower shell 2 and the sealing cover 5). As the two gears gradually mesh, the volume of the pressure chamber 17 continuously decreases, and the oil inside the chamber is squeezed by the gear teeth, causing the pressure to continuously increase. When the oil pressure in the pressure chamber 17 is higher than the working pressure of the external oil-using equipment, the high-pressure oil will be delivered to the external oil-using equipment through the oil outlet 23 of the lower shell 2, thus realizing the pressurization and supply of oil.

[0040] Automatic end-face clearance compensation stage: During high-pressure oil transportation, the high-pressure oil in the pressure chamber 17 acts on the upper end face of the middle shell 8. Since the horizontal displacement of the middle shell 8 is limited only by the positioning pin 12, its axial movement can float within a certain range. The downward pressure of the high-pressure oil on the middle shell 8 is superimposed on the elastic pressure of the compression spring 13, pushing the middle shell 8 to move further downward, making the lower end face of the middle shell 8 fit more tightly with the upper end face of the driving gear 6 and the driven gear 7, automatically reducing the end-face clearance between the gear end face and the middle shell 8. This compensation effect increases with the increase of the pressure in the pressure chamber 17, which can significantly reduce the leakage of oil from the end-face clearance to the suction chamber 16 under high-pressure conditions, ensuring the volumetric efficiency and output pressure stability of the gear pump; when the pressure in the pressure chamber 17 decreases, the middle shell 8 still remains in contact with the gear end face under the action of the compression spring 13, maintaining the sealing effect.

[0041] Continuous Cycle and Shutdown Phase: With the actuator 15 continuously powered on, the above-mentioned process of "gear rotation - oil intake - oil pressurization and delivery - end face gap compensation" will continue to cycle, achieving a continuous and stable supply of oil. When the external oil-using equipment stops working or the actuator 15 is powered off, the rotating magnetic field of the actuator 15 disappears, and the magnet 9 gradually stops rotating after losing its electromagnetic driving force. The driving gear 6 and driven gear 7 stop rotating along with the magnet 9, and the oil intake, pressurization, and delivery processes terminate synchronously. The high-pressure oil remaining in the oil pressure chamber 17 will be slowly delivered to the outside through the oil outlet 23. The pressure inside the chamber gradually decreases, and the middle shell 8, under the continuous elastic pressure of the compression spring 13, always maintains a tight fit with the upper end face of the driving gear 6 and driven gear 7, returning to the initial sealing state, waiting for the next power-on start of the actuator 15 to enter a new working cycle.

[0042] The embodiments of this application have been described above with reference to the accompanying drawings. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. This application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A miniature gear pump with automatic end-face clearance compensation function, characterized in that, The pump body (1) includes a pump body (1) and a driver (15). The pump body (1) includes a lower housing (2), a long shaft pin (3), a short shaft pin (4), a sealing cover (5), a drive gear (6), a driven gear (7), a middle housing (8), a magnet (9), a connecting plate (10), a main shaft spring (11), a positioning pin (12), and a clamping spring (13). The lower housing (2) has an 8-shaped groove (21) for accommodating the drive gear (6) and the driven gear (7). The lower housing (2) has a groove extending to the 8-shaped groove. The groove (21) has an oil inlet (22) and an oil outlet (23), and is provided with a first positioning hole (24), a second positioning hole (25), a third positioning hole (26) and a fourth positioning hole (27). The long shaft pin (3) is inserted into the first positioning hole (24), and a main shaft spring (11) is provided between its lower end and the bottom of the first positioning hole (24). The short shaft pin (4) is inserted into the second positioning hole (25). The driving gear (6) is mounted on the long shaft pin (3) and can rotate relative to it. The driven gear (7) is mounted on the short shaft pin (4) and meshes with the driving gear (6). The middle shell (8) is positioned in the third positioning hole (27) by a positioning pin (12). 26) The lower end face of the middle shell (8) abuts against the upper end face of the driving gear (6) and the driven gear (7) with the fourth positioning hole (27). The top of the inner side of the sealing cover (5) is provided with a centering groove (51) that is aligned with the first positioning hole (24). The upper end of the long shaft pin (3) abuts against the centering groove (51). The compression spring (13) is located between the middle shell (8) and the sealing cover (5). The connecting plate (10) is fixed to the lower shell (2) by screws and presses the sealing cover (5). The magnet (9) is inserted into the long shaft pin (3) and connected to the driving gear (6). The driver (15) is fixed to the connecting plate (10) by screws. After being powered on, it can drive the magnet (9) to rotate.

2. The micro gear pump with automatic end-face clearance compensation function according to claim 1, characterized in that, The lower shell (2) is also provided with a sealing groove (28), and the lower horizontal end face of the sealing cover (5) is provided with a second extrusion part (53), and a sealing ring (14) is provided between the second extrusion part (53) and the sealing groove (28).

3. The micro gear pump with automatic end-face clearance compensation function according to claim 1, characterized in that, The long shaft pin (3) has a centering cone surface (31) at the upper end and an anti-rotation groove (32) at the lower end. The hook of the main shaft spring (11) is installed in the anti-rotation groove (32). The long shaft pin (3) abuts against the centering groove (51) of the sealing cover (5) through the centering cone surface (31).

4. The micro gear pump with automatic end-face clearance compensation function according to claim 1, characterized in that, The short shaft pin (4) has an anti-rotation part (41) at its upper end, and the middle shell (8) abuts against the anti-rotation part (41) to restrict the rotation of the short shaft pin (4).

5. The micro gear pump with automatic end-face clearance compensation function according to claim 1, characterized in that, The drive gear (6) has a drive shaft sleeve (61) extending from its upper end. The outer surface of the drive shaft sleeve (61) is provided with a hexagonal key (62). The magnet (9) has an isolation sleeve (92) injection molded inside. The isolation sleeve (92) is provided with a hexagonal keyway (921). The magnet (9) is connected to the drive gear (6) through the cooperation of the hexagonal keyway (921) and the hexagonal key (62).

6. The micro gear pump with automatic end-face clearance compensation function according to claim 5, characterized in that, The magnet (9) is provided with a corrosion-resistant metal protective shell (91) on the outside, and the magnet (9) can rotate relative to the long shaft pin (3).

7. The micro gear pump with automatic end-face clearance compensation function according to claim 1, characterized in that, The sealing cover (5) has a first compression part (52) on the inner side of the annular step in the middle, and a compression spring (13) is set between the middle shell (8) and the first compression part (52).

8. The micro gear pump with automatic end-face clearance compensation function according to claim 1, characterized in that, The lower end face of the housing of the driver (15) is provided with a sealing groove (151), and a sealing ring (152) is provided between the sealing groove (151) and the upper end of the connecting plate (10).

9. The micro gear pump with automatic end-face clearance compensation function according to claim 1, characterized in that, The middle shell (8) is provided with a positioning hole (81). The positioning pin (12) passes through the positioning hole (81) and is inserted into the third positioning hole (26) and the fourth positioning hole (27) to realize the positioning of the middle shell (8).

10. The micro gear pump with automatic end-face clearance compensation function according to claim 1, characterized in that, The lower end face of the middle shell (8), the tooth profiles of the driving gear (6) and the driven gear (7) and the inner wall of the figure-eight groove (21) of the lower shell (2) form an oil suction chamber (16). The oil suction chamber (16) is connected to the oil inlet (22). In the area enclosed by the lower shell (2) and the sealing cover (5), the space other than the oil suction chamber (16) is the oil pressure chamber (17). The oil pressure chamber (17) is connected to the oil outlet (23).

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