Injection pump

Abstract

The utility model discloses an injection pump which comprises a controller, a first driving motor, a second driving motor, a rotary transmission component, a linear transmission component, a sample injector and a rotary valve, the first driving motor can be controlled to drive the push rod of the sample injector to do reciprocating motion through the rotary transmission assembly and the linear transmission assembly so as to suck fluid into the sample injector or discharge the fluid out of the sample injector; the second driving motor can be controlled to switch the fluid inlet and / or the fluid outlet of the sample injector through the rotary valve; the linear transmission assembly comprises a precise screw rod connected to the rotary transmission assembly and a back-clearance-free nut arranged on the precise screw rod in a sleeving mode, the back-clearance-free nut and a push rod of the sample injector are relatively fixed, the rotary transmission assembly is connected between the first driving motor and the screw rod, and the first driving motor controls the rotation of the rotary transmission assembly to drive the precise screw rod to rotate. And the non-backlash nut is driven to do reciprocating motion along the precise screw rod. Therefore, the axial clearance between the nut and the screw rod is eliminated, and the control precision of the injection pump is improved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the precise fluid control equipment technical field, specifically about a syringe pump. BACKGROUND

[0002] A precise syringe pump for laboratory is a high-precision flow control device, which is widely used in multiple scientific research fields, including pharmaceutical test, chemical test, biological test, food science test, mass spectrum analysis and microfluidics, etc. For example, in the pharmaceutical test research, the precise syringe pump is used for accurately delivering drugs, conducting pharmacokinetics and pharmacodynamics research, and accurately controlling the addition of drug ingredients in the drug formula and preparation process; in the mass spectrum analysis, the syringe pump is used for accurately controlling the introduction of samples to obtain high-quality analysis results; in the biological field, the syringe pump is used for cell culture, tissue engineering and biochemical experiments, and accurately controls the delivery of bioactive substances.

[0003] In the existing syringe pump, the cooperation of the screw rod and the nut is usually used as the mechanism for transmitting kinetic energy, and due to the machining precision between the screw rod and the nut, axial movement gap inevitably exists, which affects the flow control precision of the syringe pump.

[0004] The information disclosed in this BACKGROUND section is only intended to increase an understanding of the general background of the application, and should not be taken as an acknowledgement or any form of suggestion that this information forms prior art that is already known to those of ordinary skill in the art. SUMMARY

[0005] The utility model aims at providing a syringe pump, which can solve the problem that the flow control precision of the prior art syringe pump is affected by the machining precision of the screw rod and the nut.

[0006] In order to achieve the above-mentioned purpose, the technical scheme provided by a specific embodiment of the utility model is as follows:

[0007] A syringe pump, the syringe pump comprising a controller, a first drive motor, a second drive motor, a rotary transmission assembly, a linear transmission assembly, a sample injector and a rotary valve;

[0008] The first drive motor can be controlled by the controller to drive the push rod of the sample injector to reciprocate through the rotary transmission assembly and the linear transmission assembly, and then suck fluid into the sample injector or discharge fluid out of the sample injector;

[0009] The second drive motor can be controlled by the controller to switch the fluid inlet and / or fluid outlet of the sample injector through the rotary valve;

[0010] The linear transmission assembly comprises a precision lead screw connected to the rotary transmission assembly and a backlash-free nut sleeved on the precision lead screw, the backlash-free nut and the push rod of the sample injector are fixed relative to each other, the rotary transmission assembly is drivingly connected between the first driving motor and the lead screw, and the first driving motor drives the backlash-free nut to reciprocate along the precision lead screw by controlling the rotation of the rotary transmission assembly.

[0011] In one or more embodiments of the utility model, the backlash-free nut comprises a first nut and a second nut connected to each other, the first nut comprises a first abutting surface facing the second nut, and the second nut comprises a second abutting surface facing the first nut.

[0012] The backlash-free nut further comprises an elastic member abutting between the first abutting surface and the second abutting surface, and the elastic member has a force for moving the first nut and the second nut away from each other.

[0013] In one or more embodiments of the utility model, the second nut comprises a cap and a cap head movably connected along the axial direction thereof, the second abutting surface is formed on the cap, and the cap head is located on the side of the cap away from the first nut and threadedly connected with the lead screw.

[0014] In one or more embodiments of the utility model, the inner cavity of the cap is provided with a hollow conical compression member, and the compression member has a gradually decreasing opening inner diameter in the direction away from the cap head.

[0015] The cap head comprises a boss which can be fitted into the opening of the compression member, and the outer side edge of the boss can be attached to the inner wall of the opening of the compression member.

[0016] In one or more embodiments of the utility model, the injection pump further comprises a rack, the lower end of the precision lead screw is fixed on the rack through a bearing sleeve, the upper end of the precision lead screw is sleeved in a sleeve bearing, and the sleeve bearing is axially fitted with a wave spring.

[0017] In one or more embodiments of the utility model, the precision lead screw is parallel to the output shaft of the first driving motor, the backlash-free nut is drivingly connected with the push rod of the sample injector through a connecting member; and the injection pump further comprises a guide shaft parallel to the precision lead screw, and the connecting member is slidably sleeved on the guide shaft.

[0018] In one or more embodiments of the utility model, the push rod of the sample injector is arranged in parallel and at intervals with the linear bearing, the connecting member comprises a horizontal connecting arm between the push rod of the sample injector and the precision lead screw, and the horizontal connecting arm has a first position at the bottom end and a second position at the top end.

[0019] When the horizontal connecting arm is in the first position, the push rod of the sample injector is in a maximum stretched state;

[0020] When the horizontal connecting arm is in the second position, the push rod of the sample injector is in a maximum advanced state.

[0021] In one or more embodiments of the present application, the syringe pump further comprises a proximity sensor mounted on the first driving motor, and the proximity sensor is used to detect the position of the back-lash-free nut to determine the zero point position of the sample injector.

[0022] In one or more embodiments of the present application, the syringe pump comprises a first encoder for monitoring the rotation angle of the first driving motor, and the controller is used to compare the rotation pulse for controlling the rotation of the first driving motor with the feedback pulse of the first encoder to perform rotation pulse compensation on the first driving motor.

[0023] In one or more embodiments of the present application, the syringe pump comprises a second encoder for monitoring the rotation angle of the second driving motor, and the controller is used to compare the rotation pulse for controlling the rotation of the second driving motor with the feedback pulse of the second encoder to perform rotation pulse compensation on the second driving motor.

[0024] In one or more embodiments of the present application, the syringe pump further comprises a communication module in communication with an external device, and the communication module is RS485 and / or CANopen.

[0025] Compared with the prior art, the syringe pump of the present application drives the push rod of the sample injector to reciprocate through the first driving motor, the rotary transmission assembly and the linear transmission assembly, and the second driving motor can switch the fluid inlet and / or fluid outlet of the sample injector through the rotary valve, so as to realize the suction of fluid into the sample injector or the discharge of fluid out of the sample injector. In this process, since the linear transmission assembly adopts the combination of the precision lead screw and the back-lash-free nut, the axial gap between the nut and the precision lead screw can be eliminated, and the accuracy of the flow control of the syringe pump is ensured. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical scheme in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments described in the present application, and other drawings can also be obtained according to these drawings without creative labor for those skilled in the art.

[0027] Figure 1 It is an embodiment of the structure of the syringe pump of the present application.

[0028] Figure 2 Figure 1 is a combination structure diagram of the first driving motor and the first synchronous wheel of the injection pump in an embodiment of the present application;

[0029] Figure 3 Figure 2 is a combination structure diagram of the first driving motor, the rotary transmission assembly and the linear transmission assembly of the injection pump in an embodiment of the present application;

[0030] Figure 4 Figure 3 is a combination structure diagram of the linear transmission assembly of the injection pump and the sample injector in an embodiment of the present application;

[0031] Figure 5 Figure 4 is a combination structure diagram of the second driving motor and the rotary valve of the injection pump in an embodiment of the present application;

[0032] Figure 6 Figure 5 is a structure schematic diagram of the linear transmission assembly of the injection pump in an embodiment of the present application;

[0033] Figure 7 Figure 6 is a sectional view of the linear transmission assembly along the A-A direction shown in Figure 5; Figure 6

[0034] Figure 8 Figure 7 is a structure schematic diagram of the thread cooperation of the first nut, the second nut and the precision screw rod of the injection pump in an embodiment of the present application. DETAILED DESCRIPTION

[0035] In order to make the person skilled in the art better understand the technical scheme in the present application, the technical scheme in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by the person skilled in the art without creative labor should belong to the protection scope of the present application.

[0036] Reference Figure 1 The injection pump 100 in an embodiment of the present application is introduced, which comprises a controller 11, a first driving motor 20, a second driving motor 30, a rotary transmission assembly 40, a linear transmission assembly 50, a sample injector 60 and a rotary valve 70.

[0037] Reference Figure 2 and Figure 5 ​The first drive motor 20 can be controlled by the controller 11 to drive the push rod 61 of the injector 60 to reciprocate through the rotary transmission assembly 40 and the linear transmission assembly 50, thereby sucking fluid into the injector 60 or discharging fluid from the injector 60. The second drive motor 30 can be controlled by the controller 11 to switch the fluid inlet and / or fluid outlet of the injector 60 through the rotary valve 70.

[0038] With ginseng Figure 2 and Figure 3 Specifically, the rotary transmission assembly 40 includes a first synchronous wheel 41 connected to the output end of the first drive motor 20, and a second synchronous wheel 42 in transmission connection with the first synchronous wheel 41. The second synchronous wheel 42 is connected to the linear transmission assembly 50 to convert the rotary driving force of the first drive motor 20 into a linear driving force. It can be seen that the first synchronous wheel 41 is essentially a driving wheel directly connected to the first drive motor 20, while the second synchronous wheel 42 is a driven wheel indirectly driven by the first synchronous wheel 41. The linear transmission assembly 50 includes a precision screw 51 and a backlash-free nut 52 that fits on the precision screw 51. The precision screw 51 is parallel to the output shaft of the first drive motor 20 and can be mounted on the axis of the second synchronous wheel 42. In this way, when the precision screw 51 rotates forward and backward with the second synchronous wheel 42, the backlash-free nut 52 fitted thereon can reciprocate up and down along the precision screw 51 under the guidance of the thread.

[0039] In the present embodiment, the first drive motor 20 and the second drive motor 30 can both be stepper motors. The controller 11 can be integrated on the PCB board 10 to connect with an internal or external power supply to realize the motor control function described in each embodiment of the present application. Generally, the controller 11 can be an integrated circuit including a microcontroller (MCU). It is well known to those skilled in the art that the microcontroller 11 can include a central processing unit (CPU), a read-only memory module (ROM), a random access memory module (RAM), a timing module, a digital-to-analog conversion module (A / D Converter), and several input / output ports. Of course, the control device can also use other forms of integrated circuits, such as application-specific integrated circuits (ASIC) or field-programmable gate arrays (FPGA).

[0040] With ginseng Figure 6 and Figure 7In the embodiment, the backlash-free nut 52 comprises a first nut 521 and a second nut 522 connected to each other, the first nut 521 comprises a first abutting surface 5211 facing the second nut 522, and the second nut 522 comprises a second abutting surface 5221 facing the first nut 521. The backlash-free nut 52 further comprises an elastic member 523 abutting between the first abutting surface 5211 and the second abutting surface 5221, and the elastic member 523 has a force to separate the first nut 521 and the second nut 522 from each other.

[0041] Fig. 1 shows a schematic diagram of an injection pump according to the present application. Figure 8 Fig. 2 shows a schematic diagram of a state where the first nut 521 and the second nut 522 of the backlash-free nut 52 are threadedly engaged with the precision lead screw 51, and the elastic member 523 is substantially always in an elastically compressed state between the first abutting surface 5211 and the second abutting surface 5221. Under the abutment of the elastic member 523, the upper surface of the inner circle thread of the first nut 521 abuts against the lower surface of the thread of the lead screw 51, and at the same time, the lower surface of the inner circle thread of the second nut 522 abuts against the upper surface of the thread of the lead screw 51. In this way, no matter whether the backlash-free nut 52 moves upward or downward along the precision lead screw 51, there will be no clearance allowance between the axial direction of the backlash-free nut 52 and the thread of the precision lead screw 51, and the driving force of the driving mechanism can be precisely fed back to the movement stroke of the backlash-free nut 52, thereby improving the accuracy of the flow control of the injection pump.

[0042] Specifically, in the embodiment, the second nut 522 comprises a cap 5222 and a cap head 5223 movably connected along the axial direction of the second nut 522, the second abutting surface 5221 is formed on the cap 5222, and the cap head 5223 is located on the side of the cap 5222 away from the first nut 521, and the cap head 5223 is threadedly connected with the lead screw 51. That is, the part of the second nut 522 threadedly engaged with the precision lead screw 51 is the cap head 5223, the cap 5222 is movably connected with the cap head 5223 along the axial direction, and when the second abutting surface 5221 is pressed by the elastic member 523, the pressure is indirectly transmitted to the cap head 5223, thereby improving the reliability of the elastic member 523 to eliminate the axial clearance between the first nut 521, the second nut 522 and the thread of the precision lead screw 51.

[0043] Furthermore, the inner cavity of the cap 5222 of the second nut 522 is also provided with a hollow frustum-shaped pressing member 5224, which has an opening inner diameter that gradually decreases in the direction away from the cap head 5223. The cap head 5223 includes a boss 5225 that can fit within the opening of the pressing member 5224, and the outer edge of the boss 5225 can fit against the inner wall of the opening of the pressing member 5224. Through the guidance of the inner wall of the pressing member 5224, the direction of the force applied by the cap 5222 to the cap head 5223 can be made more parallel to the axial direction of the precision screw 51, ensuring that the first nut 521 and the second nut 522 in the backlash-free nut 52 are better axially attached to the threads of the corresponding precision screw 51.

[0044] In a further transmission structure, the backlash-free nut 52 is connected to the push rod 61 of the sample injector 60 through the connecting piece 54. In this way, when the backlash-free nut 52 reciprocates up and down along the precision screw 51, it can simultaneously drive the push rod 61 of the sample injector 60 to reciprocate up and down. Figure 4 As shown, when the push rod 61 of the injector 60 moves upward, the fluid is discharged from the injector 60 to the outside of the injector 60; conversely, when the push rod 61 of the injector 60 moves downward, the fluid is sucked into the injector 60 from the outside of the injector 60.

[0045] The syringe pump also includes a frame 101. The lower end of the precision screw 51 is fixed to the frame 101 via a bearing sleeve. The upper end of the precision screw is sleeved within a sleeve bearing, and a wave spring (not shown) is installed axially in the sleeve bearing. This arrangement ensures that the wave spring can axially tension the sleeve bearing, preventing it from moving up and down during use.

[0046] Continue to cooperate with Figure 4 In this embodiment, the injection pump 100 also includes a guide shaft 53 parallel to the precision screw 51, and the connecting member 54 is slidably fitted on the guide shaft 53. The guide shaft 53 is used to accurately guide the movement direction of the backlash-free nut 52 together with the precision screw 51, so as to ensure smoother control of the push rod 61 of the injector 60. Specifically, the push rod 61 of the injector 60 is arranged parallel to and spaced apart from the precision screw 51, and the connecting member 54 includes a horizontal connecting arm 541 located between the push rod 61 of the injector 60 and the precision screw 51, and the horizontal connecting arm 541 has a first position located at the bottom end and a second position located at the top end. When the horizontal connecting arm 541 is in the first position, the push rod 61 of the injector 60 is in a maximum tension state; and when the horizontal connecting arm 541 is in the second position, the push rod 61 of the injector 60 is in a maximum propulsion state.

[0047] To further improve the precision of the syringe pump 100, in an embodiment, the syringe pump 100 can further comprise a first encoder 22 for monitoring the rotation angle of the first drive motor 20, and the controller 11 is configured to compare the rotation pulses for controlling the rotation of the first drive motor 20 with the feedback pulses of the first encoder 22, so as to perform rotation pulse compensation for the first drive motor 20. Similarly, the syringe pump 100 can further comprise a second encoder 31 for monitoring the rotation angle of the second drive motor 30, and the controller 11 is configured to compare the rotation pulses for controlling the rotation of the second drive motor 30 with the feedback pulses of the second encoder 31, so as to perform rotation pulse compensation for the second drive motor 30.

[0048] In an embodiment, the syringe pump 100 can further cooperate with an external weighing module (not shown in the figure, for example, a precision balance) for detecting the sample fluid mass of the sample injector 60, and determining the precision and / or accuracy of the syringe pump 100 based on the sample fluid mass. For example, the weighing module can collect a certain amount of data of the sample fluid of the sample injector 60, and compare the sample fluid mass based on these data and the corresponding instructions of the controller 11, so as to determine the precision and accuracy of the syringe pump 100.

[0049] In an embodiment, the syringe pump 100 further comprises a proximity sensor 21 mounted on the first drive motor 20, which is configured to detect the position of the backlash-free nut 52 to determine the zero point position of the sample injector 60. The type of proximity sensor 21 can be selected according to the actual application scenario, for example, an inductive proximity sensor, a capacitive proximity sensor, an ultrasonic proximity sensor, an infrared proximity sensor, an optoelectronic proximity sensor, a magnetic proximity sensor, and a LiDAR proximity sensor, etc., which are not limited in the present application.

[0050] In an embodiment, the syringe pump 100 further comprises a communication module for communicating with external devices, which is RS485 and / or CANopen. The communication module can be similarly integrated with the controller 11 on the PCB board 10, so that the PCB board 10 can be connected to a computer or other external devices, so as to update the control program of the syringe pump 100, and realize firmware upgrade.

[0051] In the use process of the injection pump provided in the above embodiment, the PCB 10 (controller 11) drives the push rod 61 of the sample injector 60 through the first drive motor 20, the rotary transmission assembly 40 and the linear transmission assembly 50, and at the same time, the PCB 10 (controller 11) also drives the rotary valve 70 to rotate through the second drive motor 30 and the shaft coupling 71. In this process, with the rotation of the rotary valve 70, the sample injector 60 corresponds to switch different sample inlets or outlets, and cooperates with the reciprocating movement of the push rod 61 to suck fluid from the specified sample inlet or discharge fluid from the specified sample outlet. In the overall transmission structure, the linear transmission assembly adopts the combination of the backlash-free nut and the precision screw rod, which can better eliminate the movement gap between the nut and the precision screw rod in the axial direction, and ensure the accurate control of the fluid suction or discharge flow of the injection pump.

[0052] It is obvious for those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or essential characteristics of the present application. Therefore, the embodiments should be regarded as exemplary and non-limiting, and the scope of the present application is defined by the appended claims rather than the above description, and all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present application. Any reference signs in the claims should not be regarded as limiting the claims involved.

[0053] In addition, it should be understood that although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the description manner of the specification is only for the sake of clarity, and those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that those skilled in the art can understand.

Claims

1. A syringe pump, characterized in that: The injection pump includes a controller, a first drive motor, a second drive motor, a rotary transmission assembly, a linear transmission assembly, an injector and a rotary valve; The first drive motor can be controlled by the controller to drive the push rod of the injector to reciprocate through the rotary transmission component and the linear transmission component, thereby sucking fluid into the injector or discharging fluid from the injector; The second driving motor can be controlled by the controller to switch the fluid inlet and / or fluid outlet of the injector through the rotary valve; The linear transmission assembly includes a precision screw connected to the rotary transmission assembly and a backlash-free nut sleeved on the precision screw. The backlash-free nut and the push rod of the injector are fixed relative to each other. The rotary transmission assembly is connected between the first drive motor and the screw. The first drive motor drives the backlash-free nut to reciprocate along the precision screw by controlling the rotation of the rotary transmission assembly.

2. The injection pump according to claim 1, characterized in that The backlash-free nut includes a first nut and a second nut connected to each other, the first nut includes a first abutting surface facing the second nut, and the second nut includes a second abutting surface facing the first nut; The backlash-free nut further includes an elastic member abutting between the first abutting surface and the second abutting surface, wherein the elastic member has a force that forces the first nut and the second nut to move away from each other.

3. The injection pump according to claim 2, characterized in that The second nut includes a cap and a cap head movably connected along its axial direction, the second abutting surface is formed on the cap, the cap head is located on a side of the cap away from the first nut, and the cap head is threadedly connected to the screw rod.

4. The injection pump according to claim 3, characterized in that The inner cavity of the cap is provided with a hollow frustum-shaped pressing piece, and the pressing piece has an opening inner diameter that gradually decreases in the direction away from the cap head; The cap head comprises a boss which can be matched in the opening of the pressing piece, and the outer edge of the boss can be fitted to the inner wall of the opening of the pressing piece.

5. The injection pump according to claim 1, characterized in that The injection pump also includes a frame, the lower end of the precision screw is fixed to the frame through a bearing sleeve, the upper end of the precision screw is sleeved in a sleeve bearing, and a wave spring is axially mounted on the sleeve bearing.

6. The injection pump according to any one of claims 1 to 5, characterized in that The precision screw is parallel to the output shaft of the first drive motor, and the backlash-free nut is connected to the push rod of the injector through a connecting piece; the injection pump also includes a guide shaft parallel to the precision screw, and the connecting piece can be slidably fitted on the guide shaft.

7. The injection pump according to claim 6, characterized in that The push rod of the injector is arranged parallel to and spaced apart from the linear bearing, the connecting member includes a horizontal connecting arm located between the push rod of the injector and the precision screw, the horizontal connecting arm having a first position located at the bottom end and a second position located at the top end; When the horizontal connecting arm is located at the first position, the push rod of the injector is in a maximum stretching state; When the horizontal connecting arm is located at the second position, the push rod of the injector is in a maximum advancement state.

8. The injection pump according to claim 1, characterized in that The injection pump further comprises a proximity sensor mounted on the first drive motor, wherein the proximity sensor is used to detect the position of the backlash-free nut to determine the zero position of the injector.

9. The injection pump according to claim 1, characterized in that The injection pump includes a first encoder for monitoring the rotation angle of the first drive motor, and the controller is used to compare the rotation pulse for controlling the rotation of the first drive motor with the feedback pulse of the first encoder to perform rotation pulse compensation on the first drive motor; And / or, the injection pump includes a second encoder for monitoring the rotation angle of the second drive motor, and the controller is used to compare the rotation pulse for controlling the rotation of the second drive motor and the feedback pulse of the second encoder to perform rotation pulse compensation for the second drive motor.

10. The injection pump according to claim 1, characterized in that The injection pump further includes a communication module for communicating with an external device, and the communication module is RS485 and / or CANopen.

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