Micro helical gear pump with controllable axial force

Abstract

The present application relates to gear pump technical field, specifically a controllable axial force micro helical gear pump, the present application includes the driving gear part and driven gear part installed in the pump shell, and the power motor part driving the driving gear part to rotate, the driving shaft of the driving gear part has the through section of the rotor of the power motor part, the through section is uniformly distributed with a plurality of armatures, the electromagnetic coil is arranged around the armature outer circle and fixed in the pump shell cavity, and the electromagnetic coil is coaxial with the driving shaft, when the driving shaft rotates, the electromagnetic coil and the armature cooperate to form the axial tension of the driving shaft, and the axial tension is opposite to the working axial force direction generated by the driving shaft. The present application has simple structure, can dynamically respond and accurately offset the working axial force, thereby reducing the gear end face and bearing wear, improving the operation reliability and life.

Description

Technical Field

[0001] This invention relates to the field of gear pump technology, specifically a micro helical gear pump with controllable axial force. Background Technology

[0002] Helical gear pumps are widely used in micro-fluid transport fields such as medical devices, fine chemicals, and automotive electronic cooling systems due to their advantages of stable flow and low pulsation. However, during the meshing transmission of helical gears, the inclined tooth surfaces generate a working axial force parallel to the axis. This working axial force is an inherent characteristic of helical gear pumps, and it acts on the gear shaft and bearings, accelerating the wear of the bearings and gear end faces, and shortening the pump's service life.

[0003] Traditional methods for balancing axial forces, such as creating balancing grooves or using thrust bearings, are difficult to implement effectively within the limited space of a micropump and would increase structural complexity and manufacturing costs.

[0004] As described in Chinese Patent Publication No. CN114320888B, entitled "A Helical Gear Pump and a Method for Eliminating Axial Force Thereof," a floating axial force compensation is achieved by using a compensating spring in conjunction with a floating bearing. However, this type of mechanical passive compensation method has inherent limitations in practical applications: Firstly, the compensation force of the spring is linearly determined by its stiffness and compression, resulting in a fixed value or a gradually changing value within a limited range. This makes it impossible to match the dynamically changing axial force in real time. This can easily lead to undercompensation or overcompensation, making it difficult to achieve stable and optimal control of the axial force. Secondly, the mechanical spring system has a slow response speed and cannot adapt to rapid changes in axial force during transient processes such as pump start-up, shutdown, speed changes, or sudden load changes.

[0005] Therefore, this issue urgently needs to be addressed. Summary of the Invention

[0006] To avoid and overcome the technical problems existing in the prior art, the present invention provides a micro helical gear pump with controllable axial force. It has a simple structure and can dynamically respond to and accurately counteract the working axial force, thereby reducing wear on the gear end face and bearing, and improving operational reliability and service life.

[0007] To achieve the above objectives, the present invention provides the following technical solution: A micro helical gear pump with controllable axial force includes a driving gear section and a driven gear section installed in a pump casing, and a power motor section that drives the driving gear section to rotate. The driving shaft of the driving gear section has a through section that passes through the rotor of the power motor section. Several armatures are evenly distributed circumferentially on the through section. Electromagnetic coils are arranged around the outer periphery of the armatures and fixed in the inner cavity of the pump casing. The electromagnetic coils are coaxially distributed with the driving shaft. When the driving shaft rotates, the electromagnetic coils and armatures cooperate to form an axial pulling force on the driving shaft. The axial pulling force is opposite to the direction of the working axial force generated by the driving shaft.

[0008] As a further aspect of the present invention: the driving shaft of the driving gear part and the driven shaft of the driven gear part are both mounted in the pump housing cavity through sliding bearings at both ends of the gears on the driving gear part. The side wall of the sliding bearing is provided with a diamond-shaped hole that passes through the sliding bearing. The diamond-shaped holes are configured to be at least two spirally distributed around the circumference of the sliding bearing. The long axis of the diamond-shaped holes is located on the spiral trajectory of their distribution, and the spiral trajectories of the diamond-shaped holes on the two coaxial sliding bearings have opposite directions of rotation.

[0009] As a further embodiment of the present invention, the length ratio of the two diagonals of the rhomboid hole is 0.4-0.8.

[0010] As a further embodiment of the present invention: the outer surfaces of the driven shaft of the driving shaft and the driven gear are respectively provided with a first transmission groove and a second transmission groove, and the inner circumferences of the driving helical gear and the driven helical gear are respectively provided with a snap-fit ​​portion that snaps into the inner cavity of the second transmission groove and the first transmission groove.

[0011] As a further embodiment of the present invention: the water inlet of the pump casing is connected to the liquid inlet pipe, and a hydrocyclone separator for separating impurities is installed on the liquid inlet pipe.

[0012] As a further embodiment of the present invention: the pump housing includes a front housing for assembling the drive gear and the driven gear, and a rear housing for assembling the power motor and the electromagnetic coil, the front housing and the rear housing being assembled to each other by flanges.

[0013] As a further embodiment of the present invention: a non-circular anti-rotation block is fixed to the outer periphery of the shaft of the drive shaft, and the anti-rotation block is axially inserted into the rotor of the power motor.

[0014] As a further aspect of the present invention: the end faces of the driving helical gear and the driven helical gear are provided with a plurality of clover-shaped grooves evenly distributed around the corresponding axis, and the pointed cones of the clover-shaped grooves point in the opposite direction to the rotation direction of the corresponding driving helical gear and the driven helical gear.

[0015] As a further embodiment of the present invention, a throttling ring groove is coaxially provided on the end faces of the driving helical gear and the driven helical gear.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. This application solves the problem of excessive axial force in micro helical gear pumps by having a drive shaft pass through the rotor and installing a cooperating electromagnetic coil and armature at the drive shaft passage. The electromagnetic coil, in conjunction with the rotating armature, generates a directional and adjustable axial electromagnetic force to actively counteract the working axial force generated by the helical gear. This fundamentally solves the problem of excessive axial force in micro helical gear pumps, significantly reduces bearing load, extends pump lifespan, and allows the pump to operate stably at higher pressures.

[0017] 2. Both ends of the drive shaft and driven shaft are supported by sliding bearings. The sliding bearings are cylindrical, with multiple through-holes in the sidewalls. These holes are not axially arranged, but rather distributed circumferentially around the sliding bearing along a predetermined helical line, with the major axis of each hole located on its helical trajectory. Importantly, the helical trajectories of the holes on the sliding bearings at both ends of the drive shaft are opposite, and similarly, the helical trajectories of the holes on the sliding bearings at both ends of the driven shaft are also opposite. Taking the drive shaft as an example, the two diamond-shaped holes with opposite helical trajectories on the sliding bearings at both ends of the drive shaft both draw the lubricating fluid from both ends of the drive shaft towards the gear end face in the middle (i.e., the end face of the driving helical gear), thus forming a stable lubricating film. With this arrangement, when the shaft rotates within the bearing and there is an axial tendency, especially at the sliding bearing at the end where the driving lubricant is away from the gear end face, the liquid flowing through the diamond-shaped holes will be squeezed in the direction of the diamond corners to form a hydrodynamic pressure effect, and the spiral distribution of the diamond-shaped holes will produce a reverse conveying effect, thereby playing a role in balancing the axial force and enhancing lubrication.

[0018] 3. To facilitate miniaturization and ensure reliable connection, the driving and driven helical gears are injection molded from wear-resistant engineering plastics. Before injection molding, the driven shaft with the first transmission groove and the driving shaft with the second transmission groove are placed into the mold. After injection molding, the plastic material on the inner edge of the gears fills and wraps around these grooves, forming a strong snap-fit, thereby achieving synchronous rotation between the gears and the shafts. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the present invention.

[0020] Figure 2 This is a schematic diagram of the sliding bearing in this invention.

[0021] Figure 3 This is a schematic diagram of the active gear section in this invention.

[0022] Figure 4 This is a schematic diagram of the driven gear section in this invention.

[0023] Figure 5 This is a schematic diagram of the axial structure of the active helical gear in this invention.

[0024] In the diagram: 10, front housing; 20, rear housing; 30, driven gear section; 31, driven shaft; 311, first transmission groove; 32, driven helical gear; 40, driving gear section; 41, driving shaft; 411, armature; 412, second transmission groove; 413, anti-rotation block; 42, driving helical gear; 421, cloverleaf-shaped groove; 422, throttling ring groove; 50, electromagnetic coil; 60, power motor section; 70, liquid inlet pipe; 71, hydrocyclone separator; 80, sliding bearing; 81, diamond-shaped hole; 90, shielding cover. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] For ease of understanding, the specific structure and operation of the present invention will be further described below with reference to the accompanying drawings: The specific structure of this invention is as follows: Figure 1-5 As shown, its main structure includes a pump casing and a drive gear 40, a driven gear 30 and a power motor 60 installed inside the pump casing.

[0027] like Figure 1 As shown, the pump casing is divided into a front casing 10 and a rear casing 20, which are connected by flanges and bolts. The front casing 10 forms a pump chamber, housing a drive gear section 40 and a driven gear section 30. The drive gear section 40 includes a drive shaft 41 and a drive helical gear 42 fixed thereon; the driven gear section 30 includes a driven shaft 31 and a driven helical gear 32 fixed thereon. The drive helical gear 42 and the driven helical gear 32 mesh with each other. The front casing 10 is provided with an inlet and an outlet (not fully shown in the figure).

[0028] like Figure 1 As shown, the power motor unit 60 is installed inside the rear housing 20 and is used to drive the drive shaft 41 to rotate. The drive shaft 41 extends rearward and passes through the rotor of the power motor unit 60 (in the figure, the rotor and the drive shaft 41 can be considered as one piece, fixedly connected, or forming a plug-in anti-rotation fit, such as on the drive shaft 41, as...). Figure 1 and Figure 2As shown, a non-circular (e.g., flat or regular polygonal) anti-rotation block 413 is fixed. This anti-rotation block 413 is fitted into the rotor of the power motor section 60 in a corresponding shape to transmit torque and prevent relative rotation between the drive shaft 41 and the motor rotor. Several armatures 411 made of magnetically conductive material are uniformly embedded or fixed circumferentially on the through section of the drive shaft 41. A ring-shaped electromagnetic coil 50 is coaxially distributed around the outer periphery of the through section of the drive shaft 41 and is fixedly installed in the inner cavity of the rear housing 20. The electromagnetic coil 50 is connected to a control circuit board via wires. Specifically, the control circuit board can be either built into the inner cavity of the rear housing 20 or externally placed within the inner cavity of the rear housing 20. When the electromagnetic coil 50 is energized, it generates a magnetic field that interacts with the rotating armatures 411, producing an axial pulling or pushing force depending on the direction of the current. In this design, by controlling the current, an axial pulling force (e.g., a force pointing towards the power motor 60) is generated that is opposite to the working axial force of the drive shaft 41 (e.g., a force away from the direction of the power motor 60).

[0029] Based on the above, such as Figure 1 As shown, both ends of the drive shaft 41 (excluding the extension section) and the driven shaft 31 are supported by sliding bearings 80. Figure 2 The sliding bearing 80 is cylindrical, with multiple through-holes 81 machined on its sidewalls. These diamond-shaped holes 81 are not axially arranged, but rather distributed circumferentially around the sliding bearing 80 along a predetermined helical line, with the major axis of each diamond-shaped hole 81 located along its helical trajectory. The ratio of the long diagonal to the short diagonal of each diamond-shaped hole 81 is between 0.4 and 0.8. Importantly, the helical trajectories of the diamond-shaped holes 81 on the sliding bearings 80 at both ends of the drive shaft 41 are opposite, and similarly, the helical trajectories of the diamond-shaped holes 81 on the sliding bearings 80 at both ends of the driven shaft 31 are also opposite, to guide the lubricant located on the corresponding drive shaft 41 and driven shaft 31 to the gear end faces in the middle of the corresponding drive shaft 41 and driven shaft 31. Taking the drive shaft 41 as an example, assuming... Figure 1 The central drive shaft 41 rotates clockwise. The helical trajectory of the sliding bearing 80 located above the drive helical gear 42 is set to left-hand, and the helical trajectory of the sliding bearing 80 located below the drive helical gear 42 is set to right-hand. During operation, the diamond-shaped holes 81 on both sliding bearings 80 converge the lubricating fluid towards the end face of the central drive helical gear 42, thereby forming a stable lubricating film. With this arrangement, when the shaft rotates within the bearings and there is an axial tendency, especially at the sliding bearing 80 at the end where the driving lubricating fluid is away from the gear end face, the fluid flowing through the diamond-shaped holes 81 will be squeezed in the direction of the diamond corners, creating a hydrodynamic pressure effect. The helical distribution of the diamond-shaped holes 81 also produces a reverse conveying effect, thereby helping to balance the axial force and enhance lubrication.

[0030] like Figure 3 and Figure 4 As shown, to facilitate miniaturization and ensure reliable connection, the driving helical gear 42 and the driven helical gear 32 are injection molded from wear-resistant engineering plastic. Before injection molding, the driven shaft 31 with the first transmission groove 311 and the driving shaft 41 with the second transmission groove 412 are placed into the mold. After injection molding, the plastic material on the inner edge of the gears fills and wraps around these grooves, forming a strong snap-fit, thereby achieving synchronous rotation of the gears and shafts.

[0031] Based on the above, such as Figure 1 As shown, a hydrocyclone separator 71 is installed on the inlet pipe 70 to separate denser solid particles before the liquid enters the pump chamber, thus playing a pre-filtration and protection role.

[0032] Based on the above, such as Figure 1 As shown, the rear housing 20 is internally divided into two chambers by a metal shield 90: a humidification chamber and a drying chamber. The stator windings of the motor unit 60 and the shaft extension of the drive shaft 41 are located in the humidification chamber, which may come into contact with trace amounts of leaked media (i.e., the penetration point of the drive shaft 41). The rotor (permanent magnet) of the motor unit 60 and the crucial electromagnetic coil 50 are located in the drying chamber, completely isolated from the media to ensure long-term reliable operation. In practice, preferably, the shield 90 is flange-sealed to the front housing 10, and the shield 90 is also flange-sealed to the rear housing 20, ensuring stable isolation between the media and the drying chamber.

[0033] Based on the above, such as Figure 5 As shown, multiple cloverleaf-shaped grooves 421, evenly distributed around the axis, are machined on the end face of the driving helical gear 42 (and similarly for the driven helical gear 32). These grooves have a wedge-shaped cross-section, with the pointed end (cone) pointing in the opposite direction of gear rotation. When the gear rotates, liquid is drawn into the gradually widening grooves, generating dynamic pressure that slightly lifts the gear end face, forming a lubricating film. Furthermore, an annular throttling groove 422 is machined in the center of the end face to balance the pressure distribution. This comprehensively reduces leakage of the conveyed medium and improves the efficiency of the micro helical gear pump.

[0034] Of course, those skilled in the art will recognize that the present invention is not limited to the details of the exemplary embodiments described above, but also includes the same or similar structures that can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0035] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0036] The technologies, shapes, and structures not described in detail in this invention are all known technologies.

Claims

1. A micro helical gear pump with controllable axial force, comprising a driving gear section (40) and a driven gear section (30) installed in a pump housing, and a power motor section (60) for driving the driving gear section (40) to rotate, wherein, The driving gear unit (40) includes a driving shaft (41) and a driving helical gear (42) fixed thereon, and the driven gear unit (30) includes a driven shaft (31) and a driven helical gear (32) fixed thereon. The driving gear unit (40) has a through section on the driving shaft (41) that passes through the rotor of the power motor unit (60). A plurality of armatures (411) are evenly distributed around the through section. An electromagnetic coil (50) fixed in the inner cavity of the pump housing is arranged around the outer periphery of the armatures (411). The electromagnetic coil (50) is coaxially distributed with the driving shaft (41). When the driving shaft (41) rotates, the electromagnetic coil (50) and the armatures (411) cooperate to form an axial pulling force on the driving shaft (41). The axial pulling force is opposite to the working axial force generated by the driving shaft (41). The drive shaft (41) and driven shaft (31) are mounted on the inner cavity of the pump housing via sliding bearings (80) at both ends of the gear. The side wall of the sliding bearing (80) is provided with a diamond-shaped hole (81) that passes through the sliding bearing (80). The diamond-shaped holes (81) are arranged in a spiral distribution around the sliding bearing (80) in the circumference of at least two. The long axis of the diamond-shaped holes (81) is located on the spiral trajectory of its distribution, and the spiral trajectories of the diamond-shaped holes (81) on the two coaxial sliding bearings (80) are opposite in direction. The diamond-shaped holes (81) on the two coaxial sliding bearings (80) converge the lubricating fluid to the gear end face in the middle to form a lubricating film and generate an auxiliary balancing axial force.

2. The micro helical gear pump with controllable axial force according to claim 1, characterized in that, The length ratio of the two diagonals of the rhomboid hole (81) is 0.4-0.

8.

3. A micro helical gear pump with controllable axial force according to any one of claims 1-2, characterized in that, The outer surfaces of the driven shaft (31) of the drive shaft (41) and the driven gear (30) are respectively provided with a first transmission groove (311) and a second transmission groove (412). The inner circumferences of the drive helical gear (42) and the driven helical gear (32) are respectively provided with a snap-fit ​​portion that snaps into the inner cavity of the second transmission groove (412) and the first transmission groove (311).

4. A micro helical gear pump with controllable axial force according to any one of claims 1-2, characterized in that, The pump casing is connected to the inlet pipe (70), and a hydrocyclone separator (71) for separating impurities is installed on the inlet pipe (70).

5. A micro helical gear pump with controllable axial force according to any one of claims 1-2, characterized in that, The pump housing includes a front housing (10) for assembling the drive gear (40) and the driven gear (30), and a rear housing (20) for assembling the power motor (60) and the electromagnetic coil (50). The front housing (10) and the rear housing (20) are assembled to each other by flanges.

6. A micro helical gear pump with controllable axial force according to any one of claims 1-2, characterized in that, The outer periphery of the shaft of the drive shaft (41) is fixed with a non-circular anti-rotation block (413), and the anti-rotation block (413) is axially connected to the rotor of the power motor (60).

7. A micro helical gear pump with controllable axial force according to any one of claims 1-2, characterized in that, The end faces of the driving helical gear (42) and the driven helical gear (32) are provided with a number of clover-shaped grooves (421) evenly distributed around the corresponding axis. The pointed cones of the clover-shaped grooves (421) point in the opposite direction to the rotation direction of the corresponding driving helical gear (42) and the driven helical gear (32).

8. A micro helical gear pump with controllable axial force according to any one of claims 1-2, characterized in that, Throttling ring grooves (422) are coaxially provided on the end faces of the driving helical gear (42) and the driven helical gear (32).

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