A miniature high-precision stepping plunger pump

Abstract

The present invention provides a miniature high-precision stepping plunger pump, which belongs to the technical field of motor pumps. The present invention provides a pump head with a pump cavity and a motor at both ends of a pump body with a moving cavity, and the plunger is slidably arranged in the pump cavity, and a nut with an internal threaded hole is slidably arranged in the moving cavity along the axial direction of the plunger. The screw is connected to the internal threaded hole, the nut is connected to the plunger, and the other end of the screw is connected to the main shaft of the motor. The motor drives the screw to rotate, and the driving nut drives the plunger to move in the pump cavity, changing the volume of the pump cavity to achieve liquid suction and discharge. Not only does the coaxial arrangement of the plunger, nut, screw and main shaft of the motor be achieved, ensuring the stability of the plunger movement speed, ensuring a smooth flow rate and higher precision, in addition, the length space occupied by the nut and screw structure is only the length of the rack in the original structure, avoiding the problem of large space occupation caused by the need to set a spur gear mechanism, a bevel gear structure, etc., which is conducive to the miniaturization of the pump and has a wider range of uses.

Description

Technical Field

[0001] The present invention relates to the technical field of motor pumps, and in particular to a miniature high-precision stepping plunger pump. Background Art

[0002] Plunger pumps are usually used as liquid pumps and are widely used in hydraulic supply. The plunger moves back and forth in the cylinder, causing the volume in the inner cavity of the cylinder to change, thereby realizing the process of sucking and discharging liquid.

[0003] Currently, in the plunger pumps on the market, the plunger is usually driven by an eccentric wheel, a crankshaft connecting rod and other structures, that is, the plunger is driven to move in the inner cavity of the cylinder by the eccentric wheel and the crankshaft connecting rod. Although the above structure can meet the movement requirements of the plunger, whether it is an eccentric wheel or a crankshaft connecting rod, the plunger is arranged along the radial direction of the eccentric wheel or the crankshaft, and is realized by the rotation of the eccentric wheel or the crankshaft. As a result, the movement speed of the plunger will vary linearly with the sine and cosine curves, and the volume change of the inner cavity of the rod body also has the problem of uniform speed. As a result, the flow rate of liquid suction and discharge is unstable, making it difficult to adapt to the requirements of high-precision use. In addition, Chinese patent CN202073760U discloses a micro-flow variable plunger pump equipped with a stepper motor, including a pump body, a pump head and a pump tail respectively arranged at both ends of the pump body, an oil inlet and an oil outlet arranged on the pump head, a slide groove that allows the plunger to move is arranged in the pump head, and a rack is arranged along the axial direction of the tail end of the plunger, the rack is engaged with the gear installed on the shaft, the pump tail is connected to the motion conversion mechanism housing, a stepper motor is arranged in the motion conversion mechanism housing, the stepper motor is connected to the spur gear mechanism, the spur gear mechanism is connected to the bevel gear mechanism through a transmission shaft, and the bevel gear mechanism is arranged on the shaft, that is, through The bevel gear mechanism is driven by the stepper motor, and the spur gear mechanism is driven to rotate by the bevel gear mechanism, so that the spur gear mechanism drives the rack to move along the axial direction of the plunger. Since the plunger and the stepper motor are driven by gears and racks, the effectiveness of the transmission and the stability of the movement speed are ensured, thereby ensuring that the plunger can move at a uniform speed and maintain the stability of the flow rate. However, not only the length of the rack must be accommodated between the plunger and the stepper motor to meet the plunger stroke requirements, but also additional spur gear mechanisms, bevel gear mechanisms, etc. are required, which take up a lot of space and make its overall volume large, which is not conducive to miniaturization and has large usage restrictions. Summary of the Invention

[0004] In response to the above-mentioned problems existing in the prior art, the present invention aims to provide a miniature high-precision stepping plunger pump, in which a nut with an internal thread is arranged between the plunger and the motor to replace the existing rack structure. At the same time, the main shaft of the motor is arranged along the axial direction of the plunger and fixedly connected with a screw rod, and the screw rod extends into the nut and is threadedly connected. At the same time, the outer wall of the nut is slid on the pump body along the axial direction of the plunger, so that the plunger can move back and forth at a uniform speed when the motor rotates forward and reverse, the flow rate is stable, the suction and discharge requirements are met, the precision is higher, and the overall length is only the length of the original rack, avoiding the problem of a larger structural volume caused by the need to set a spur gear mechanism, a bevel gear mechanism, etc., which is conducive to miniaturization and has higher adaptability.

[0005] The specific technical solutions are as follows:

[0006] A miniature high-precision stepping plunger pump has the following features:

[0007] The pump body has a moving cavity passing through both ends, and a first limiting portion extending from one end to the other end is provided on the inner wall of the moving cavity;

[0008] The pump head is installed on one end of the pump body. The end of the pump head close to the pump body is provided with a pump cavity connected to the moving cavity, and the other end of the pump head is provided with an inlet and an outlet connected to the pump cavity;

[0009] A plunger is slidably disposed in the pump chamber;

[0010] A nut is coaxially arranged with the plunger and disposed in the movable cavity. A second limiting portion is provided on an outer wall of the nut for circumferentially limiting the first limiting portion. One end of the nut is connected to the plunger, and an internal threaded hole is provided at the other end of the nut.

[0011] The motor is arranged at the end of the pump body away from the pump head, and the main shaft of the motor is coaxially arranged with the plunger;

[0012] A screw rod, one end of which is threadedly connected to the internal threaded hole of the nut, and the other end of which is fixedly connected to the main shaft of the motor.

[0013] In the above-mentioned micro high-precision stepping plunger pump, a ceramic rod is provided between the nut and the plunger, and two ends of the ceramic rod are fixedly connected to the positioning nut and the plunger respectively.

[0014] The above-mentioned micro high-precision stepping plunger pump, wherein the plunger has a center hole, one end of the ceramic rod is inserted into the center hole and passes through, and the end of the ceramic rod passing through the center hole is sleeved with a sealing frame, one side of the sealing frame rests on the plunger, and at the same time, a first sealing ring is also sleeved on the outside of the sealing frame, and the first sealing ring is pressed against the sealing frame.

[0015] In the above-mentioned micro high-precision stepping plunger pump, the inner wall of the pump cavity of the pump head is provided with avoidance holes corresponding to the ceramic rod, the sealing frame and the first sealing ring.

[0016] In the above-mentioned micro high-precision stepping plunger pump, the first limiting portion is a guide rail protruding from the inner wall of the moving cavity, and the second limiting portion is a sliding groove concave on the surface of the nut.

[0017] The above-mentioned miniature high-precision stepping plunger pump, wherein a plurality of expansion holes connected to the pump chamber are opened on the plunger and located beside the center hole, a deformable part is arranged in the expansion hole, an electromagnet is arranged at the end of the expansion hole away from the pump chamber, a permanent magnet is arranged on the side of the deformable part away from the pump chamber, and the deformable part is deformed toward the pump chamber or the expansion hole.

[0018] The above-mentioned micro high-precision stepping plunger pump, wherein the deformable part is a piston, the piston is slidably arranged in the expansion hole, and a plurality of second sealing rings are arranged between the outer wall of the piston and the inner wall of the expansion hole. At the same time, the permanent magnet is embedded in the piston, and a limiting edge is provided at the opening of the expansion hole close to one end of the pump chamber, and a locking edge is provided at the end of the piston away from the pump chamber, and a plurality of second sealing rings are located between the limiting edge and the locking edge.

[0019] The above-mentioned miniature high-precision stepping plunger pump, wherein the deformable part is a leather cup, and a limiting edge is provided at the opening of the expansion hole near one end of the pump chamber. At the same time, an inward-concave groove is provided on the inner wall of the expansion hole and on the side of the pump chamber away from the limiting edge, and a retaining ring is provided in the groove, and the outer edge of the leather cup is tightly attached to the limiting edge and is pressed by the retaining ring. At the same time, a sealing gasket is provided between the leather cup and the retaining ring, and a permanent magnet is provided on the side of the leather cup away from the pump chamber.

[0020] The above-mentioned micro high-precision stepping plunger pump has a protruding guide plate on the inner wall of the expansion hole and along the axial direction of the plunger, and a slider is provided on the guide plate. At the same time, the permanent magnet is installed on the slider, and the slider is connected to the side of the leather cup away from the pump chamber.

[0021] The above-mentioned miniature high-precision stepping plunger pump, in which the side of the leather cup facing away from the pump chamber is arranged on the connecting block, a push-pull rod is arranged between the slider and the connecting block, and an embedded hole with a retracted hole opening is opened on the connecting block. One end of the push-pull rod is fixedly connected to the slider, and the other end is arranged in a "T"-shaped head and embedded in the embedded hole.

[0022] The above-mentioned miniature high-precision stepping plunger pump, wherein a protective component is arranged between the screw and the main shaft of the motor, the protective component includes a collar and a locking screw, one end of the collar is fixedly connected to the screw, and the other end of the collar is sleeved on the outside of the main shaft, and a plurality of locking holes are opened on the collar along its radial direction, and a locking screw is threadedly connected in each locking hole, and one end of the locking screw extends into the collar and rests on the main shaft.

[0023] The positive effects of the above technical solution are:

[0024] The above-mentioned miniature high-precision stepping plunger pump is achieved by arranging a nut with an internal thread coaxially arranged with the plunger in the moving cavity of the pump body, and the nut is connected to the plunger. In addition, a motor is provided at the end of the pump body, and a screw is fixedly connected to the main shaft of the motor. The screw cooperates with the internal thread of the nut to realize the coaxial arrangement of the plunger, nut, screw and the main shaft of the motor, thereby ensuring the stability of the plunger movement speed, improving the flow rate stability and higher precision. In addition, the structure of the screw nut occupies a small space. Compared with the existing rack-driven structure, the overall length is only the length of the original rack, avoiding the problem of a larger structural volume caused by the need to set up a spur gear mechanism, a bevel gear mechanism, etc., and has a better miniaturization effect and a wider range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic diagram of a state of an embodiment of a micro high-precision stepping plunger pump of the present invention;

[0026] Figure 2 Schematic diagram of another state of an embodiment of a miniature high-precision stepping plunger pump of the present invention;

[0027] Figure 3 1 is another schematic diagram of another state of an embodiment of a micro high-precision stepping plunger pump of the present invention;

[0028] Figure 4 A schematic diagram of a state of another embodiment of a micro high-precision stepping plunger pump of the present invention;

[0029] Figure 5 This is a schematic diagram of another state of another embodiment of a micro high-precision stepping plunger pump of the present invention.

[0030] In the accompanying drawings: 1. Pump body; 11. Moving chamber; 12. First limiting part; 2. Pump head; 21. Pump chamber; 22. Inlet; 23. Outlet; 24. Avoidance hole; 3. Plunger; 31. Center hole; 32. Sealing frame; 33. First sealing ring; 34. Expansion hole; 35. Electromagnet; 36. Permanent magnet; 37. Piston; 38. Leather cup; 371. Second sealing ring; 381. Retaining ring; 382. Guide plate; 383. Slider; 384. Connecting block; 385. Push-pull rod; 4. Nut; 41. Second limiting part; 42. Internal threaded hole; 5. Motor; 51. Spindle; 6. Screw; 7. Ceramic rod. Implementation Method

[0031] In order to make the technical means, creative features, objectives and effects of the present invention easier to understand, the following embodiments are combined with the attached Figure 1 To the attached Figure 5The technical solution provided by the present invention is described in detail, but the following content is not intended to limit the present invention.

[0032] Figure 1 A schematic diagram of a state of an embodiment of a micro high-precision stepping plunger pump of the present invention; Figure 4 FIG. 1 is a schematic diagram of another embodiment of a micro high-precision stepping plunger pump of the present invention. Figure 1 and Figure 4 As shown, the micro high-precision stepping plunger pump provided in this embodiment includes: a pump body 1, a pump head 2, a plunger 3, a nut 4, a motor 5 and a screw 6, wherein the pump head 2 and the motor 5 are respectively arranged at both ends of the pump body 1, and the plunger 3, the nut 4 and the screw 6 are arranged in a combined structure composed of the pump body 1 and the pump head 2.

[0033] Specifically, the pump body 1 has a movement cavity 11 extending through both ends, providing space for the subsequent installation and movement of the plunger 3 and nut 4. Furthermore, a first stopper 12 extending from one end to the other is provided on the inner wall of the movement cavity 11. This first stopper 12 guides the pump body 1 axially and limits its circumferential rotation, thereby providing conditions for subsequent movement and preventing rotation of the nut 4.

[0034] Specifically, the pump head 2 is mounted on one end of the pump body 1. At this time, a pump chamber 21 connected to the movable chamber 11 is provided at the end of the pump head 2 close to the pump body 1, that is, the pump chamber 21 is connected to the movable chamber 11, which provides a condition for the plunger 3 in the subsequent pump chamber 21 to move, so that one end of the plunger 3 needs to extend into the movable chamber 11 to maintain the normal movement of the plunger 3. In addition, an inlet 22 and an outlet 23 connected to the pump chamber 21 are provided at the other end of the pump head 2, that is, the volume of the pump chamber 21 can be changed by the movement of the plunger 3, so that the liquid flowing into the inlet 22 can enter the pump chamber 21, and the liquid in the pump chamber 21 can be discharged from the outlet 23, thereby meeting the use requirements of suction and discharge. It is worth noting that solenoid valves are respectively provided on the inlet 22 and the outlet 23, that is, the opening and closing control of the inlet 22 and the outlet 23 is realized by the solenoid valve, thereby meeting the use requirements of closing the outlet 23 when suctioning and closing the inlet 22 when discharging, thereby ensuring the normal suction and discharge.

[0035] Specifically, the plunger 3 is slidably arranged in the pump chamber 21, that is, the plunger 3 moves in the pump chamber 21 to change the volume of the pump chamber 21, thereby meeting the use requirements of suction and discharge. At this time, in order to ensure the sealing performance between the plunger 3 and the pump chamber 21, a number of sealing rings are sleeved on the outer wall of the plunger 3, and the sealing rings are against the inner wall of the pump chamber 21. The structure is simple and reliable.

[0036] Specifically, the nut 4 is coaxially arranged with the plunger 3. At this time, the nut 4 is set in the movable chamber 11, so that the nut 4 has sufficient space to move. In addition, a second limiting portion 41 is provided on the outer wall of the nut 4, which is circumferentially limited with the first limiting portion 12. That is, the first limiting portion 12 and the second limiting portion 41 limit the rotation of the nut 4 in the circumferential direction of the plunger 3, while ensuring the axial movement of the nut 4 along the plunger 3 in the movable chamber 11. In addition, one end of the nut 4 is connected to the plunger 3, and the other end of the nut 4 is provided with an internal threaded hole 42, so that when the nut 4 moves along the axial direction of the plunger 3, the nut 4 can drive the plunger 3 to move along its axial direction, thereby enabling the plunger 3 to move in the pump chamber 21, meeting the use requirements of the pump to suck and discharge liquid.

[0037] Specifically, the motor 5 is positioned at the end of the pump body 1 facing away from the pump head 2. That is, the motor 5 and the pump head 2 are positioned at opposite ends of the pump body 1. This allows the motor 5 and the pump head 2 to be separated by the pump body 1, providing space for the subsequent installation and movement of the nut 4 and the screw rod 6. Furthermore, the main shaft 51 of the motor 5 is coaxially arranged with the plunger 3, so that the main shaft 51 of the motor 5 and the nut 4 are coaxially located. It is worth noting that the motor 5 includes, but is not limited to, a stepper motor 5, as long as it meets the requirements of the application.

[0038] Specifically, one end of the screw rod 6 is threadedly connected to the internal thread of the nut 4. Since the nut 4 is restricted from circumferential rotation by the first limiting portion 12 and the second limiting portion 41, when the screw rod 6 rotates forward and backward, the nut 4 can reciprocate along the axial direction of the screw rod 6, thereby changing the position of the nut 4 within the pump body 1, thereby driving the plunger 3 to move within the pump chamber 21 to achieve liquid suction and discharge. At this time, the other end of the screw rod 6 is fixedly connected to the main shaft 51 of the motor 5. That is, the motor 5 directly drives the screw rod 6 to rotate, thereby driving the nut 4 and driving the plunger 3 to move within the pump chamber 21. In addition, since the control motor 5 rotates at a uniform speed, the screw rod 6 also rotates at a uniform speed, thereby driving the nut 4 to move at a uniform speed, so that the plunger 3 also moves at a uniform speed, thereby ensuring the uniform speed of liquid suction and discharge, ensuring the stability of the flow rate, and higher precision. Moreover, the total length of the matching structure of the nut 4 and the screw rod 6 only requires the length of the rack in the existing rack structure, and there is no need to set up a spur gear mechanism, a bevel gear mechanism, etc., which will cause the structure to be larger in volume. This is conducive to miniaturization, has fewer usage restrictions, and is more adaptable.

[0039] More specifically, a ceramic rod 7 is also provided between the nut 4 and the plunger 3. At this time, the two ends of the ceramic rod 7 are fixedly connected to the positioning nut 4 and the plunger 3 respectively, that is, the nut 4 and the plunger 3 are connected through the ceramic rod 7, which has good thermal insulation performance, high structural strength, good wear resistance, and longer service life.

[0040] More specifically, a center hole 31 is formed in the center of the plunger 3, and one end of the ceramic rod 7 is inserted into the center hole 31 and passes through it. At the same time, a sealing frame 32 is also provided on the end of the ceramic rod 7 that passes through the center hole 31, and one side of the sealing frame 32 is pressed against the plunger 3. That is, the sealing frame 32 is used to seal the gap where the ceramic rod 7 passes through the center hole 31, and the sealing performance is better. At the same time, a first sealing ring 33 is also provided on the outside of the sealing frame 32, and the first sealing ring 33 is pressed against the sealing frame 32, so that the sealing frame 32 can be pressed against the ceramic rod 7 through the first sealing ring 33, thereby achieving a seal between the sealing frame 32 and the ceramic rod 7, thereby ensuring the sealing performance of the connection between the ceramic plate and the plunger 3.

[0041] In addition, a socket is opened along the radial direction of the nut 4 at one end of the nut 4 close to the plunger 3. At this time, a connecting hole is opened along the axial direction of the end of the nut 4 connected to the ceramic rod 7, and the socket is connected to the connecting hole. At the same time, a limiting screw is arranged in the socket, and the end of the limiting screw is pressed tightly on the end of the ceramic rod 7 connected to the nut 4, which effectively ensures the connection reliability between the ceramic rod 7 and the nut 4 and prevents the ceramic rod 7 from falling off the nut 4.

[0042] More specifically, an avoidance hole 24 corresponding to the ceramic rod 7, the sealing frame 32 and the first sealing ring 33 is further provided on the inner wall of the pump chamber 21 of the pump head 2. Preferably, the inlet 22 or the outlet 23 is connected to the avoidance hole 24, which can not only reduce the processing amount and improve the structural utilization rate, but also prevent the problem that the end face of the plunger 3 cannot be completely fitted with the wall of the pump chamber 21 due to the protruding structure at the end of the plunger 3 due to the setting of the sealing structure on the plunger 3, thereby ensuring that the liquid in the pump chamber 21 can be completely discharged and avoiding liquid residue.

[0043] More specifically, the first limiting portion 12 in the pump body 1 is a guide rail protruding from the inner wall of the moving chamber 11, and the second limiting portion 41 is a concave sliding groove located on the surface of the nut 4, so that when the nut 4 is installed in the moving chamber 11, the guide rail slides in the sliding groove, thereby realizing the sliding of the nut 4 in the moving chamber 11.

[0044] More specifically, a plurality of expansion holes 34 connected to the pump chamber 21 are provided on the plunger 3 and located beside the central hole 31. Preferably, the plurality of expansion holes 34 are distributed in a circular array with the central hole 31 as the axis, so that the expansion holes 34 are evenly distributed on the plunger 3. At the same time, a deformable member is provided in the expansion hole 34, and an electromagnet 35 is provided at the end of the expansion hole 34 away from the pump chamber 21, while a permanent magnet 36 is provided on the side of the deformable member away from the pump chamber 21. The permanent magnet 36 cooperates with the electromagnet 35, that is, when current is passed through the electromagnet 35 and the direction of the current is changed, the electromagnet 35 will generate a magnetic field with the opposite magnetic pole direction, thereby attracting the permanent magnet 36 to approach the electromagnet 35 or pushing the permanent magnet 36 in the direction away from the electromagnet 35, thereby driving the deformable member to deform toward the expansion hole 34 or toward the side of the expansion hole 34. The pump chamber 21 is deformed. When the deformable member is deformed toward the expansion hole 34, part of the space of the expansion hole 34 is connected to the pump chamber 21, thereby expanding the volume of the pump chamber 21 and increasing the flow rate of the pump. When the deformable member is deformed toward the pump chamber 21, part of the space of the pump chamber 21 can be occupied by the deformable member, thereby reducing the volume of the pump chamber 21 and reducing the flow rate of the pump. That is, the pump flow rate can be adjusted without disassembling and replacing the original pump body 1, pump head 2, motor 5, nut 4, screw rod 6 and other structures. The adjustment is more convenient, there is no need to replace the pump, and the adaptability is better. It is worth noting that, since the movement and movement direction of the deformable member in the expansion hole 34 are controlled by the electromagnet 35, the floating installation of the deformable member in the expansion hole 34 is realized, and the deformation state of the deformable member can be adaptively adjusted following the movement direction of the plunger 3, that is, when the flow rate is increased, the deformable member can be pushed toward the side of the pump chamber 21 during the discharge process, so that the liquid in the expansion hole 34 can also be completely discharged to avoid residue, and then the electromagnet 35 can be controlled to appropriately reduce the current and weaken the magnetic field, so that the floating deformable member can also appropriately overcome the magnetic force when the end face of the plunger 3 abuts against the cavity wall of the pump chamber 21 and be pressed back to the expansion hole 34 by the plunger 3. In this way, the problem of liquid residue caused by the end of the plunger 3 not being able to fit the wall of the pump chamber 21 is avoided; similarly, when the flow rate is reduced, the deformable part can be pushed into the pump chamber 21 during the liquid suction process to avoid excessive liquid suction, and when discharging the liquid, the electromagnet 35 can be controlled to appropriately adjust the current to weaken the magnetic field, so that when the deformable part contacts the wall of the pump chamber 21 and the end of the plunger 3 does not contact the wall of the pump chamber 21, the plunger 3 can continue to move and compress the deformable part to retract into the expansion hole 34, avoiding the problem that the deformable part presses against the plunger 3 and the end face of the plunger 3 cannot contact the wall of the pump chamber 21, and also ensuring that the liquid can be completely discharged.

[0045] In addition, an air vent connected to the movable cavity 11 is provided on the electromagnet 35. The air vent connects the spaces on both sides of the electromagnet 35, ensuring that the deformable member can be deformed smoothly toward one side of the expansion hole 34, making the structural design more reasonable.

[0046] This embodiment provides two forms of deformable elements. Figure 2 Schematic diagram of another state of an embodiment of a miniature high-precision stepping plunger pump of the present invention; Figure 3 FIG. 1 is another state diagram of an embodiment of a micro high-precision stepping plunger pump of the present invention. Figure 1 、 Figure 2 ,as well as Figure 3 As shown, the deformable member is a piston 37. In this case, the piston 37 is slidably arranged in the expansion hole 34. At the same time, a plurality of second sealing rings 371 are provided between the outer wall of the piston 37 and the inner wall of the expansion hole 34, thereby achieving a seal between the piston 37 and the expansion hole 34, thereby ensuring the overall sealing performance of the plunger 3. At the same time, the permanent magnet 36 is embedded in the piston 37, thereby achieving an integrated arrangement of the permanent magnet 36 and the piston 37. In addition, a limiting edge is provided at the orifice of the expansion hole 34 close to one end of the pump chamber 21. At the same time, a locking edge is provided at the end of the piston 37 away from the pump chamber 21, and a plurality of second sealing rings 371 are located between the limiting edge and the locking edge, effectively preventing the piston 37 from falling out of the expansion hole 34 under the action of the electromagnet 35, and the structural design is more reasonable.

[0047] Figure 4 A schematic diagram of a state of another embodiment of a micro high-precision stepping plunger pump of the present invention; Figure 5 FIG. 1 is another schematic diagram of another embodiment of a micro high-precision stepping plunger pump of the present invention. Figure 4 and Figure 5 As shown, the deformable member is configured as a leather cup 38, which is easy to deform, has good elasticity, and a long service life. In this case, a limiting edge is provided at the opening of the expanded hole 34 at one end near the pump chamber 21. At the same time, a concave clamping groove is provided on the inner wall of the expanded hole 34, on the side of the pump chamber 21 facing away from the limiting edge. A snap ring 381 is provided in the clamping groove. When the leather cup 38 is installed in the expanded hole 34, the outer edge of the leather cup 38 is tightly attached to the limiting edge and is compressed by the snap ring 381. That is, the limiting edge and snap ring 381 ensure that the leather cup 38 is installed at the opening of the expanded hole 34, and the problem of the center of the expanded hole 34 being blocked and hindering the deformation of the leather cup 38 is also prevented. At the same time, a sealing gasket is provided between the leather cup 38 and the retaining ring 381, which effectively improves the overall sealing performance of the plunger 3, and the permanent magnet 36 is provided on the side of the leather cup 38 away from the pump chamber 21, so that the permanent magnet is provided between the leather cup 38 and the electromagnet 35, so that the permanent magnet and the electromagnet 35 are both isolated from the pump chamber 21 by the leather cup 38, and the structural design is more reasonable.

[0048] More specifically, a protruding guide plate 382 is provided on the inner wall of the expansion hole 34 and along the axial direction of the plunger 3, so that the arrangement direction of the guide plate 382 is also the axial direction of the plunger 3. At the same time, a slider 383 is slidably provided in the expansion hole 34 and on the guide plate 382, ​​so that the slider 383 can move back and forth on the guide plate 382. At the same time, the permanent magnet 36 is installed on the slider 383, and the slider 383 is connected to the side of the leather cup 38 away from the pump chamber 21, that is, the guide rail and the slider 383 provide guidance for the movement of the permanent magnet 36 in the expansion hole 34, thereby ensuring the stability of the movement of the permanent magnet 36 and thus ensuring the reliability of the deformation of the leather cup 38.

[0049] More specifically, a connecting block 384 is further provided on the side of the leather cup 38 facing away from the pump chamber 21. In this case, a push-pull rod 385 is provided between the slider 383 and the connecting block 384, that is, the push-pull rod 385 serves as a connecting structure between the slider 383 and the leather cup 38. At the same time, an embedded hole with an inward-retracted opening is opened on the connecting block 384, and one end of the push-pull rod 385 is fixedly connected to the slider 383. The other end of the push-pull rod 385 is arranged in a "T"-shaped head and embedded in the embedded hole, realizing a snap connection between the push-pull rod 385 and the connecting block 384, while also preventing the push-pull rod 385 and the connecting block 384 from falling off, and the structural design is more reasonable.

[0050] More specifically, a protection component is provided between the screw rod 6 and the main shaft 51 of the motor 5. At this time, the protection component includes a collar and a locking screw, and one end of the collar is fixedly connected to the screw rod 6 so that the collar and the screw rod 6 form an integral structure. At the same time, the other end of the collar is sleeved outside the main shaft 51, and a plurality of locking holes are opened on the collar along its radial direction. A locking screw is threadedly connected in each locking hole, and one end of the locking screw extends into the collar and abuts against the main shaft 51. During installation, the assembler ensures that the collar is in the correct position according to the column. The normal push-pull force required for the movement of the plunger 3 creates a pre-tightening force for the locking screw, ensuring that the main shaft 51 of the motor 5 can rotate with the pass ring under normal circumstances. When an unexpected situation such as the plunger 3 getting stuck occurs, the nut 4 will be unable to move, thereby making the screw rod 6 and the ring unable to rotate, which will cause a great burden on the motor 5 and cause the motor 5 to burn out. At this time, the rotation of the main shaft 51 of the motor 5 can be ensured by sliding the end of the locking screw on the outer wall of the main shaft 51, preventing the motor 5 from burning out, and having better safety protection performance.

[0051] The micro high-precision stepping plunger pump provided in this embodiment includes a pump body 1, a pump head 2, a plunger 3, a nut 4, a motor 5 and a screw 6. The pump head 2 with a pump cavity 21 and the motor 5 are respectively provided at both ends of the pump body 1 with a movable cavity 11, and the plunger 3 is slidably arranged in the pump cavity 21. The nut 4 with an internal threaded hole 42 is slidably arranged in the movable cavity 11 along the axial direction of the plunger 3. The screw 6 is connected to the internal threaded hole 42, the nut 4 is connected to the plunger 3, and the other end of the screw 6 is connected to the main shaft 51 of the motor 5. The screw 6 is driven to rotate by the motor 5. The driving nut 4 drives the plunger 3 to move in the pump chamber 21, changing the volume of the pump chamber 21 to achieve liquid suction and discharge, which not only realizes the coaxial arrangement of the plunger 3, nut 4, screw rod 6 and the main shaft 51 of the motor 5, but also ensures the stability of the moving speed of the plunger 3, ensures a smooth flow rate and higher precision. In addition, the length space occupied by the structure of the nut 4 and screw rod 6 is only the length of the rack in the original structure, avoiding the problem of large space occupation caused by the need to set up a spur gear mechanism, a bevel gear structure, etc., which is conducive to the miniaturization of the pump and has a wider range of uses.

[0052] The above are only preferred embodiments of the present invention and do not limit the implementation mode and protection scope of the present invention. For those skilled in the art, it should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. A miniature high-precision stepping plunger pump, characterized in that: include: A pump body, wherein the pump body has a moving cavity passing through both ends, and a first limiting portion extending from one end to the other end is provided on the inner wall of the moving cavity; A pump head, the pump head being mounted on one end of the pump body, the pump head being close to the pump body and being provided with a pump cavity communicating with the moving cavity, and the other end of the pump head being provided with an inlet and an outlet communicating with the pump cavity; a plunger, the plunger being slidably disposed in the pump chamber; a nut, the nut being coaxially arranged with the plunger, the nut being disposed in the movable cavity, and a second limiting portion being provided on an outer wall of the nut for circumferentially limiting the first limiting portion, one end of the nut being connected to the plunger, and the other end of the nut being provided with an internal threaded hole; a motor, the motor being arranged at an end of the pump body away from the pump head, and the main shaft of the motor being coaxially arranged with the plunger; a screw rod, one end of which is threadedly connected to the internal threaded hole of the nut, and the other end of which is fixedly connected to the main shaft of the motor; A ceramic rod is provided between the nut and the plunger, and two ends of the ceramic rod are fixedly connected to the nut and the plunger respectively; The plunger has a central hole, one end of the ceramic rod is inserted into the central hole and passes through it, and the end of the ceramic rod passing through the central hole is sleeved with a sealing frame, one side of the sealing frame abuts against the plunger, and at the same time, a first sealing ring is sleeved on the outside of the sealing frame, and the first sealing ring is pressed against the sealing frame; A plurality of expansion holes connected to the pump chamber are provided on the plunger and located beside the central hole. A deformable part is provided in the expansion hole. An electromagnet is provided at one end of the expansion hole facing away from the pump chamber. A permanent magnet is provided on the side of the deformable part facing away from the pump chamber, and the deformable part is deformed toward the pump chamber or the expansion hole.

2. The micro high-precision stepping plunger pump according to claim 1, characterized in that: The inner wall of the pump cavity of the pump head is provided with avoidance holes corresponding to the ceramic rod, the sealing frame and the first sealing ring.

3. The micro high-precision stepping plunger pump according to claim 1, characterized in that: The first limiting portion is a guide rail protruding from the inner wall of the moving cavity, and the second limiting portion is a sliding groove concave on the surface of the nut.

4. The micro high-precision stepping plunger pump according to claim 1, characterized in that: The deformable part is a piston, which is slidably arranged in the expansion hole, and a plurality of second sealing rings are arranged between the outer wall of the piston and the inner wall of the expansion hole. At the same time, the permanent magnet is embedded in the piston, and a limiting edge is provided at the orifice of the expansion hole close to one end of the pump chamber, and a clamping edge is provided at the end of the piston away from the pump chamber, and a plurality of second sealing rings are located between the limiting edge and the clamping edge.

5. The micro high-precision stepping plunger pump according to claim 1, characterized in that: The deformable part is a leather cup, and a limiting edge is provided at the orifice of the expansion hole close to one end of the pump chamber. At the same time, an inward-concave groove is provided on the inner wall of the expansion hole and on the side of the limiting edge away from the pump chamber, and a retaining ring is provided in the groove. Moreover, the outer edge of the leather cup is tightly attached to the limiting edge and is pressed by the retaining ring. At the same time, a sealing gasket is provided between the leather cup and the retaining ring, and the permanent magnet is provided on the side of the leather cup away from the pump chamber.

6. The micro high-precision stepping plunger pump according to claim 5, characterized in that: A protruding guide plate is provided on the inner wall of the expansion hole and along the axial direction of the plunger, and a slider is slidably provided on the guide plate. At the same time, the permanent magnet is mounted on the slider, and the slider is connected to the side of the leather cup away from the pump chamber.

7. The micro high-precision stepping plunger pump according to claim 6, characterized in that: The side of the leather cup facing away from the pump chamber is arranged on the connecting block, a push-pull rod is arranged between the slider and the connecting block, and an embedded hole with a retracted hole is opened on the connecting block. One end of the push-pull rod is fixedly connected to the slider, and the other end is arranged in a "T" shape and embedded in the embedded hole.

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