CN219647521U

CN219647521U - Mechanism for reducing motor axial load and liquid transfer device for reducing motor axial load

Info

Publication number: CN219647521U
Application number: CN202320816600.XU
Authority: CN
Inventors: 玉智泰; 赵武军; 宋科; 李明
Original assignee: Xi'an Tianlong Science & Technology Co ltd
Current assignee: Xi'an Tianlong Science & Technology Co ltd
Priority date: 2023-04-13
Filing date: 2023-04-13
Publication date: 2023-09-08
Anticipated expiration: 2033-04-13

Abstract

The utility model discloses a mechanism for reducing the axial load of a motor and a liquid transfer device for reducing the axial load of the motor, which relate to the technical field of liquid transfer devices, wherein the mechanism for reducing the axial load of the motor comprises a shell accommodating an internal structure, one end of a screw rod is connected with the shell through a connecting bearing to form a bearing end, and the other end of the screw rod is connected with a driving motor through a coupler to form a cantilever end; the screw rod is connected with a driven part, and the driving motor can act on the screw rod and enable the driven part connected with the screw rod to drive the target piece to move along the axial direction of the screw rod. According to the mechanism for reducing the axial load of the motor and the liquid shifter for reducing the axial load of the motor, provided by the utility model, the structure that one end of the screw rod is the bearing end and the other end of the screw rod is the cantilever end is adopted, so that the axial load born by a driving motor connected with the cantilever end is greatly reduced, and the reliable high-precision long-term operation of the liquid shifter is effectively realized.

Description

Mechanism for reducing motor axial load and liquid transfer device for reducing motor axial load

Technical Field

The utility model relates to the technical field of pipettors, in particular to a mechanism for reducing axial load of a motor and the pipettor for reducing the axial load of the motor.

Background

Air displacement pipettes have the property of precise pipetting amounts, and are therefore widely used for transferring small volumes of liquid, such pipetting amounts typically being several to several tens of microliters, e.g. 5 μl, 10 μl, 15 μl, 20 μl, etc. Such pipettes typically use manual or electric actuation for air displacement fluid transfer or metering, with the actuation air displacement being typically implemented as a cylinder structure with a movable piston engagement, ensuring accurate fluid volume control by controlling the amount of piston rod displacement. The disposable pipetting consumable used with the pipetting device is usually injection molded by plastic and other materials, the pipetting pump is detachably connected with the consumable, liquid to be transferred is sucked into the consumable through displacement movement of the piston rod, then quantitative liquid is discharged at a required position to finish pipetting steps, the pipetting consumable after being used is unloaded, air lock exists between the pipetting device and the liquid to be transferred in the whole process, actual contact does not occur, pollution risks of the transferring, metering and other processes are very small, automation equipment is a great trend of future development in the fields of medical treatment, biotechnology and the like, and single or a plurality of motor-driven automation pipetting devices are configured in the equipment to be required for design.

The research on a motor-driven pipette is earlier, and U.S. patent No. 4399712a, which requires priority in 02 in 1981, discloses a scheme for physically changing the driving current of a driving motor, which uses adjustable resistors matched with sliding sheets to change the resistance value of a connecting circuit of the driving motor, so as to adjust the voltage division of the driving motor to adaptively obtain a proper driving force. US7585468B2 discloses a solution that enables the status of the drive motor to be known by means of a magnetic induction sensor, and thus a precise position control of the pipette. The technical solution disclosed in the european patent application EP1250956B1 shows in detail how the principle of air displacement is used to transfer or quantify an accurate amount of liquid to be transferred, and the corresponding air exchange time relationship curve is fitted and stored to accurately control the liquid transfer amount. US7314598B2 discloses a detailed structural design, which is still adopted in the design of pipettes which are widely used at present, wherein the design comprises the determination of pressure detection in the pipettes by pressure sensors, the limitation of movement limit positions of different limit position sensors for pistons, and the requirement of multiple sample automatic processing scenes formed by installing a plurality of pipettes in parallel. The utility model patent CN204412288U discloses a scheme of arranging a driving motor in the lower region of a shell of a liquid dispenser, and the utility model CN204314318U discloses a scheme of arranging a driving motor in the lower region of the shell of the liquid dispenser and driving a plug rod to reciprocate through belt wheel transmission. In the scheme disclosed in the utility model patent No. 112211856A, a motor is arranged at the upper part of a shell, and a belt wheel is also arranged to drive a plug rod to move. In practice, in the design of a motor-driven pipette, there will be a great limitation on the size of the motor due to space limitation, and the motor has a weak carrying capacity for additional loads, especially axial loads, and the axial loads also seriously affect the pipetting accuracy, so that the reliability of the motor is reduced due to the larger axial loads.

Therefore, how to develop a reliable load transmission mechanism, effectively reduce the axial load transmitted to the driving motor, and further realize reliable high-precision long-term operation of the pipettor is a technical problem to be solved in the field.

Disclosure of Invention

The utility model aims at: aiming at the problems, the utility model provides the mechanism for reducing the axial load of the motor and the liquid shifter for reducing the axial load of the motor, and the structure that one end of the screw rod is a bearing end and the other end of the screw rod is a cantilever end is adopted, so that the axial load born by a driving motor connected with the cantilever end is greatly reduced, and the reliable high-precision long-term operation of the liquid shifter is effectively realized.

The technical scheme adopted by the utility model is as follows:

the mechanism for reducing the axial load of the motor comprises a shell with an internal structure, wherein one end of a screw rod is connected with the shell through a connecting bearing to form a bearing end, and the other end of the screw rod is connected with a driving motor through a coupler to form a cantilever end; the screw rod is connected with a driven part, and the driving motor can act on the screw rod and enable the driven part connected with the screw rod to drive the target piece to move along the axial direction of the screw rod.

Further, the number of the connecting bearings is not less than two, and a plurality of the connecting bearings are arranged side by side along the axial direction of the screw rod.

Further, the driving motor and the coupler are connected to the outside of the shell through the mounting blocks, the cantilever end of the screw rod penetrates through the assembly hole on the shell to be matched with the coupler, and an annular gap is formed between the screw rod and the assembly hole.

Further, one side of the connecting bearing opposite to the cantilever end is provided with a plurality of compression nuts.

Further, one side of the connecting bearing opposite to the cantilever end is provided with a shaft end pressing cap for providing pressing force for the outer ring of the connecting bearing, the shell is provided with a pressing groove matched with the shaft end pressing cap, and the shaft end pressing cap can be assembled in the pressing groove through a connecting piece; the shaft end compression cap is provided with an assembly cavity for accommodating the compression nut, and when the shaft end compression cap is assembled with the shell, the compression nut is positioned in the assembly cavity and provides compression force for connecting the bearing inner ring.

The liquid transfer device for reducing the axial load of the motor comprises a shell with an internal structure, wherein the shell is provided with a liquid transfer consumable connecting part extending out of the range of the shell, one end of a plug rod is at least partially inserted into the liquid transfer consumable connecting part, further, the plug rod is connected to a screw rod through a sliding block assembly, one end of the screw rod is connected with a body through a connecting bearing to form a bearing end, and the other end of the screw rod is connected with a driving motor through a coupling to form a cantilever end; the driving motor can act on the screw rod and enable the sliding block assembly connected to the screw rod to drive the plug rod to move relative to the pipetting consumable connecting part along the axial direction of the screw rod.

Further, a pressing mechanism capable of providing pressing force for the connecting bearing is arranged on one side of the connecting bearing opposite to the cantilever end.

Further, the sliding block assembly comprises a connecting sliding block, a screw rod connecting piece and a plug rod connecting piece, wherein the screw rod connecting piece and the plug rod connecting piece are respectively arranged at two ends of the connecting sliding block, a sliding rail for providing motion constraint for the connecting sliding block is arranged in the shell, and the sliding rail is parallel to the screw rod; the screw rod is in threaded connection with the screw rod connecting piece, and one end of the plug rod is connected with the plug rod connecting piece through the assembly hole.

In summary, due to the adoption of the technical scheme, the beneficial effects of the utility model are as follows:

1. the utility model adopts the structure that one end of the screw rod is a bearing end and the other end is a cantilever end, so that most of axial load borne by the screw rod is balanced by the shell, only tiny axial load is transmitted to the driving motor through the coupler, and the reliable high-precision long-term operation of the liquid transfer device is effectively realized.

2. The utility model provides a plurality of connecting bearings to ensure higher reliability in the axial load sharing, if only one connecting bearing is arranged at the bearing end, the connecting bearing is only used for bearing the axial load when the pipetting consumable is unloaded, and the problems of safety and reliability such as the connecting bearing being pulled out, the inner ring being pulled out and the like are easily generated.

3. The screw rod sliding block structure is adopted in the liquid transfer device, and the sliding rail for providing motion constraint for the connecting sliding block is configured, so that the sliding rail also bears axial load, and the stability and reliability of the whole device are improved.

Drawings

FIG. 1 is a schematic illustration of the mechanism for reducing motor axial load of the present utility model;

FIG. 2 is a longitudinal cross-sectional view of the motor axial load reduction mechanism of the present utility model;

FIG. 3 is a schematic view of the structure of the pipette of the present utility model;

FIG. 4 is a schematic view showing the internal structure of the pipette of the present utility model;

FIG. 5 is a partially disassembled schematic illustration of a pipette of the present utility model;

FIG. 6 is a schematic view of the structure of the hold-down mechanism of the present utility model;

FIG. 7 is a schematic diagram of load transfer when the pipetting consumables of the utility model are unloaded.

The marks in the figure: 10-driving motor, 101-motor shaft, 13-installation block, 20-coupling, 30-shell, 301-lead screw, 3011-connection bearing, 3012-gland nut, 3013-shaft end gland cap, 311-annular gap, 32-slider assembly, 321-lead screw connecting piece, 33-cock stem, 40-pipetting consumable connecting piece, 401-sealing connecting piece, 50-pipetting consumable unloading piece, 501-slider abutting piece, 502-unloading connecting piece, 503-unloading sleeve.

Detailed Description

The present utility model will be described in detail with reference to the accompanying drawings.

The present utility model will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present utility model more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the utility model.

Example 1

1-2, the mechanism for reducing the axial load of the motor comprises a shell 30 containing an internal structure, wherein one end of a screw rod 301 is connected with the shell 30 through a connecting bearing 3011 to form a bearing end, and the other end of the screw rod is connected with a driving motor 10 through a coupler 20 to form a cantilever end; the screw 301 is connected with a driven part, and the driving motor 10 can act on the screw 301 and enable the driven part connected to the screw 301 to drive the target part to move along the axial direction of the screw 301.

The number of the connecting bearings 3011 is two, and the two connecting bearings 3011 are arranged side by side along the axial direction of the screw 301.

The driving motor 10 and the coupler 20 are connected to the outside of the shell 30 through the mounting block 13, the cantilever end of the screw rod 301 passes through the assembly hole on the shell 30 to be matched with the coupler 20, and an annular gap 311 is formed between the screw rod 301 and the assembly hole.

Two compression nuts 3012 are arranged on the side of the connecting bearing 3011 opposite to the cantilever end.

A shaft end pressing cap 3013 for providing pressing force for the outer ring of the connecting bearing 3011 is arranged on one side of the connecting bearing 3011 opposite to the cantilever end, a pressing groove matched with the shaft end pressing cap 3013 is formed in the shell 30, and the shaft end pressing cap 3013 can be assembled in the pressing groove through a connecting piece; the shaft end pressing cap 3013 is provided with an assembly cavity for accommodating the pressing nut 3012, and when the shaft end pressing cap 3013 is assembled with the shell 30, the pressing nut 3012 is positioned in the assembly cavity and provides pressing force for the inner ring of the connecting bearing 3011.

Fig. 2 is a longitudinal section view of a mechanism for reducing the axial load of a motor, a driving motor 10 is connected to a connecting hole of a coupling 20 through a motor shaft 101, one end of a screw rod 301 is connected to a connecting hole at the other end of the coupling 20, and the diameters of the two connecting holes of the coupling 20 are adjustable in the connecting structure, so that the diameters of the motor shaft 101 and the screw rod 301 can be adapted, and the size of the connecting holes can be adjusted through an aperture adjusting unit to realize detachable connection. The other end of the screw rod 301 is connected with the housing 30 through the connection bearing 3011, the connection bearing 3011 can balance most of the axial load received by the screw rod 301 and transfer the axial load to the connected housing 30, the connection bearing 3011 can be seen to be arranged as two or more in a longitudinal sectional view, the number of the connection bearings 3011 can be needless to be limited here, one end connected with the driving motor directly penetrates through the housing 30 and does not contain a bearing element, the end corresponds to a suspension cantilever state, the connection bearing 3011 basically does not bear the axial load in stress analysis, the axial load born by the screw rod 301 is balanced on the connection end of the connection bearing 3011, not less than 2 connection bearings 3011 can realize that the axial load balances most of the axial load received by the screw rod 301 in a small area at the end of the screw rod 301, namely a contact area of the connection bearing 3011 and transfer the axial load to the connected housing 30, thus the technical effect of only transferring the small axial load to the driving motor 10 is realized, the compression nut 3012 is arranged outside the connection bearing 3011, the compression nut is prevented from loosening during compression, the compression nut is further arranged as two or more compression nuts 3013 can be contained in the connection nut 3011, and the compression nut can be further fixed.

Example 2

The utility model provides a reduce pipettor of motor axial load, as shown in fig. 3, including the casing 30 of holding inner structure, it can be by the concatenation of metal material's meta-parts, also can be for the meta-parts concatenation of non-metal material or metal non-metal meta-parts combination concatenation forms, its outward appearance can be nearly cuboid structure, and its thickness direction's size is less than length and width direction size far away, whole can take on the platykurtic, so can satisfy the parallel cooperation of a plurality of modules in the pipettor, the scene of quick pipetting, the one end configuration of casing 30 has the pipetting consumable connecting portion 40 that stretches out the casing 30 scope, the tip of pipetting consumable connecting portion 40 is provided with sealed link 401, it can be spherical or other curved surface bulge form, be connected with pipetting consumable 100 interference fit under the drive of downforce, so can realize simple reliable quick sealed connection, pipetting consumable connecting portion 40 whole can be configured as the solid of revolution type, for example, the column body, its inside contains the air runner, the plug rod 33 can be in the axial direction of pipetting connecting portion 40 and reciprocal motion, the relative linear motion is done to the consumable 33 when the suction rod is used for the relative pipetting in the suction. The other end of the housing 30 opposite to the pipetting consumable connection part 40 is connected with a drive motor 10, and the drive motor 10 is limited to the housing 30 by a mounting block 13. The shell 30 is provided with an assembly notch, the mounting block 13 is matched with the assembly notch, the driving motor 10 is connected to the assembly notch of the shell 30 through the mounting block 13, and an accommodating space capable of arranging the coupler 20 is formed between the mounting block 13 and the assembly notch.

Fig. 4 illustrates an internal structure of the pipette, in which the driving motor 10 is connected to one end of the screw 301 through the coupling 20, the connection may be a detachable connection, the other end of the screw 301 is connected to the housing 30 through the connection bearing 3011, so that the screw 301 may rotate relative to the housing 30, one end of the slider assembly 32 is screwed to the screw 301, the other end is connected to the stopper rod 33, and the axis of the stopper rod 33 is parallel to the axis of the screw 301. The screw rod 301 may have a thread with a set pitch, the slider assembly 32 includes a connection slider, a screw rod connector 321 and a plug rod connector, the screw rod connector 321 and the plug rod connector are respectively disposed at two ends of the connection slider, a slide rail for providing motion constraint for the connection slider is disposed in the housing 30, and the slide rail is parallel to the screw rod 301 and may be parallel to the axis direction of the screw rod 301, so that the slider assembly 32 can perform sliding motion along the extending direction of the slide rail, and thus the reliability of the system operation is ensured due to the fact that the stress of the slider assembly 32 is smaller in the sliding process. The driving motor 10 may act on the screw 301 and make the slider assembly 32 connected to the screw 301 drive the stopper 33 to move along the axial direction of the screw 301 relative to the pipetting consumable connection portion 40. The stopper rod 33 and the pipetting consumable connecting part 40 cooperate with each other, the stopper rod 33 connected by the slider assembly 32 is at least partially inserted into the pipetting consumable connecting part 40, a stepped structure is arranged in the stopper rod 33, the stopper rod 33 is matched in an air flow channel in the pipetting consumable connecting part 40, a sealing structure is arranged at the top position of the pipetting consumable connecting part 40, the relative position of the sealing structure and the pipetting consumable connecting part 40 is fixed, the sealing structure is in friction motion cooperation with the stopper rod 33, the sealing reliability of the cooperation is high, when the slider assembly 32 drives the stopper rod 33 to slide up and down, the stopper rod 33 forms a suction and discharge effect on the original air in the pipetting consumable connecting part 40, further the suction effect of air displacement pipetting is realized, further the operations such as liquid suction and discharge can be realized through the pipetting consumable 100 connected with the pipetting consumable connecting part 40, and the low risk state of the pipetting body is ensured, and the cooperation of the stopper rod 33 and the pipetting consumable connecting part 40 is similar to the piston sealing cooperation. The pipette further comprises a pipetting consumable unloading part 50, the pipetting consumable unloading part 50 comprises a sliding block abutting part 501, an unloading connecting part 502 and an unloading sleeve 503, the unloading sleeve 503 is wrapped and arranged on the outer wall of the pipetting consumable connecting part 40, the end part of the unloading sleeve 503 is connected with the sliding block abutting part 501 through the unloading connecting part 502, the sliding block abutting part 501 is slidably connected with the shell 30, and the sliding block assembly 32 can abut against the sliding block abutting part 501 and acts on the sliding block abutting part 501 to enable the unloading sleeve 503 to move relative to the pipetting consumable connecting part 40 along the axial direction. When the pipetting consumables need to be unloaded (the unloading pipetting consumables are connected to the sealing connection end 401 and are not shown in the drawing), the driving motor 10 provides the pipetting consumables unloading driving force, the slider assembly 32 continues to move downwards, and contacts with the slider abutting piece 501, and after passing through the shell 30, the slider assembly is connected with the unloading sleeve 503 arranged outside the pipetting consumables connection part 40 through the unloading connection piece 502, so that the driving force of the motor is transmitted to the unloading sleeve 503 to generate relative movement with the pipetting consumables connection part 40, and the unloading sleeve 503 is almost flush with the lower part of the sealing connection end 401 along with the slider assembly 32, that is, the pipetting consumables can be basically abutted and detached from the pipetting consumables connection part 40, so as to finish the mechanical unloading of the pipetting consumables. The slider butt piece 501 department is provided with reset element, and when slider subassembly 32 upwards moves and no longer acts on slider butt piece 501, slider butt piece 501 can be through reset element upwards move, and then drives uninstallation sleeve 503 and upwards move, exposes sealed link 401, and sealed link 401 of being convenient for is connected with new pipetting consumables.

Fig. 5 illustrates a partially disassembled structure of the pipettor, when the pipettor is disassembled, the shaft end pressing cap 3013 can be disassembled first, then the screw 301 and the connecting bearing 3011 and related components connected thereto can be integrally extracted, and the connecting aperture of the coupler 20 needs to be adjusted before the extraction, so that the limit of the coupler 20 on the cantilever end of the screw 301 is released, and then the screw 301 can be rotated to withdraw from the housing 30.

The structure shown in fig. 6 simultaneously removes the screw 301 and the screw connector 321, and may not be required to be removed together in practice. One end of the screw rod 301 connected with the coupler 20 is a cantilever end, the cantilever end of the screw rod 301 passes through an assembly hole on the shell 30 to be matched with the coupler 20, and an annular gap 311 is formed between the screw rod 301 and the assembly hole. More preferably, the annular gap has a minimum gap size ranging from 0.5 mm to 2.5mm, so that the possibility of friction between the screw rod 301 and the shell 30 is avoided even if a certain axial load exists, the screw rod 301 operates more reliably, and the problems of overlarge internal stress caused by constraint of two end parts of the screw rod 301 and the like are avoided due to the design. Meanwhile, fig. 6 further illustrates that a boss structure is arranged at the bearing end of the screw rod 301, which can provide a clamping force for the connection bearing 3011, at least two connection bearings 3011 are sleeved on the screw rod 301, the inner ring of the connection bearings 3011 is abutted on the boss of the screw rod 301, the effect of no relative motion between the inner ring and the screw rod is achieved, a threaded part is arranged at the end part of the screw rod 301, two or more compression nuts 3012 are in threaded connection to compress the inner ring of the connection bearing 3011, a shaft end compression cap 3013 with an assembly cavity is arranged outside the compression nuts 3012, when the shaft end compression cap 3013 is assembled with the housing 30, the compression nuts 3012 are located in the assembly cavity, the shaft end compression cap 3013 can accommodate the compression nuts 3012 in a non-interfering manner, and the outer ring of the connection bearing 3011 can be compressed, so that the outer ring of the connection bearing 3011 and the housing are in a relatively static state, and most of axial loads can be transferred to the housing 30 through the support balance of at least two connection bearings 3011 in a small area of the bearing end.

Fig. 7 illustrates an axial load balancing effect diagram of the pipette according to the present utility model, which may be generated during unloading of the pipetting consumables, when the slider assembly 32 is not in contact with the slider abutment 501 of the pipetting consumable unloading section 50, the axial load is not suddenly changed, similar to a low axial load state in pipetting operations, and after the slider assembly 32 continues to abut downwards against the slider abutment 501, as shown in fig. 7, by force analysis of the slider assembly 32 and the screw rod 301, as shown by an arrow in fig. 7, the slider abutment 501 may generate a force on the slider assembly 32, the force is transferred to the screw rod 301 along the slider assembly 32, a load is formed along the axial direction of the screw rod 301, so that the driving motor 10 adopting a general connection design will bear the axial load, and the axial force will be serious under the accumulation effect of a long time and multiple times, the accuracy and reliability of the driving motor 10 may be seriously challenged, and the reliability of the driving motor 10 are enabled to be balanced by the housing 30 at the connection bearing 3011, only the axial load transferred to the driving motor 10, the small axial load can be transferred to the driving motor 10, even the small load can be ignored from the connection end of the small, and the connection end of the slider assembly can be almost ignored, the connection end of the cartridge 10 can be almost completely unloaded, and the consumable part can be almost completely unloaded from the end of the slider assembly is almost completely unloaded, and the end of the consumable part can be almost completely unloaded from the driving motor 10, and the consumable part can be almost completely unloaded, the end of the consumable part is almost completely unloaded, and the consumable part is completely can be completely unloaded, and the consumable part is almost completely loaded, and the consumable part is completely loaded, and the consumable in the consumable part is completely and the consumable.

The principles and embodiments of the present utility model have been described herein with reference to specific examples, which are intended to be merely illustrative of the methods of the present utility model and their core ideas. It should be noted that it will be apparent to those skilled in the art that various modifications and adaptations of the utility model can be made without departing from the principles of the utility model and these modifications and adaptations are intended to be within the scope of the utility model as defined in the following claims.

In the description of the present utility model, it should be noted that, directions or positional relationships indicated by terms such as "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., are directions or positional relationships based on those shown in the drawings, or are directions or positional relationships conventionally put in use of the inventive product, are merely for convenience of describing the present utility model and simplifying the description, and are not indicative or implying that the apparatus or element to be referred to must have a specific direction, be constructed and operated in a specific direction, and thus should not be construed as limiting the present utility model.

In the description of the present utility model, it should also be noted that, unless explicitly specified and limited otherwise, the terms "disposed," "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present utility model will be understood in specific cases by those of ordinary skill in the art.

Claims

1. The mechanism for reducing the axial load of the motor comprises a shell with an internal structure, and is characterized in that one end of a screw rod is connected with the shell through a connecting bearing to form a bearing end, and the other end of the screw rod is connected with a driving motor through a coupler to form a cantilever end; the screw rod is connected with a driven part, and the driving motor can act on the screw rod and enable the driven part connected with the screw rod to drive the target piece to move along the axial direction of the screw rod.

2. A mechanism for reducing axial load of a motor according to claim 1, wherein said number of said connecting bearings is not less than two, and a plurality of said connecting bearings are arranged side by side in the axial direction of the lead screw.

3. The motor axial load reducing mechanism according to claim 1, wherein the driving motor and the coupling are connected to the outside of the housing through a mounting block, the cantilever end of the screw rod passes through a mounting hole in the housing to be matched with the coupling, and an annular gap is formed between the screw rod and the mounting hole.

4. A motor axial load reducing mechanism according to claim 1, wherein the side of the connecting bearing opposite the cantilevered end is provided with a plurality of compression nuts.

5. The motor axial load reducing mechanism according to claim 4, wherein a shaft end pressing cap for providing pressing force for the outer ring of the connecting bearing is arranged on one side of the connecting bearing opposite to the cantilever end, a pressing groove matched with the shaft end pressing cap is formed in the shell, and the shaft end pressing cap can be assembled in the pressing groove through a connecting piece; the shaft end compression cap is provided with an assembly cavity for accommodating the compression nut, and when the shaft end compression cap is assembled with the shell, the compression nut is positioned in the assembly cavity and provides compression force for connecting the bearing inner ring.

6. The liquid transfer device for reducing the axial load of the motor comprises a shell with an internal structure, wherein the shell is provided with a liquid transfer consumable connecting part extending out of the range of the shell, and one end of a plug rod is at least partially inserted into the liquid transfer consumable connecting part; the driving motor can act on the screw rod and enable the sliding block assembly connected to the screw rod to drive the plug rod to move relative to the pipetting consumable connecting part along the axial direction of the screw rod.

7. The pipette for reducing axial load of a motor as defined in claim 6 wherein the number of said joint bearings is not less than two, and a plurality of said joint bearings are arranged side by side in the axial direction of the lead screw.

8. The pipette for reducing axial load of a motor as defined in claim 6 wherein, said drive motor and said coupling are connected to the outside of said housing by means of a mounting block, said cantilevered end of said screw rod is mated with said coupling by passing through a mounting hole in said housing, and an annular gap is formed between said screw rod and said mounting hole.

9. The pipette for reducing axial load of a motor as defined in claim 6 wherein a side of said connecting bearing opposite said cantilever end is provided with a hold down mechanism for providing hold down force to said connecting bearing.

10. The pipette for reducing axial load of a motor as defined in claim 6 wherein the slider assembly comprises a connecting slider, a screw rod connector and a plug rod connector, the screw rod connector and the plug rod connector being disposed at both ends of the connecting slider, respectively, a slide rail for providing motion constraint for the connecting slider being disposed in the housing, the slide rail being parallel to the screw rod; the screw rod is in threaded connection with the screw rod connecting piece, and one end of the plug rod is connected with the plug rod connecting piece through the assembly hole.