Infusion driving mechanism and infusion device

Abstract

According to the infusion driving mechanism and the infusion device, force generated during phase change of memory alloy serves as driving force, and the device is small in size and low in cost. The infusion driving mechanism comprises a screw rod, an indexing structure, a shifting structure and a shape memory alloy part, wherein one end of the screw rod is connected to the piston; the indexing structure is arranged on the screw and is coaxial with the screw; the stirring structure is connected with the shape memory alloy part, and the shape memory alloy part drives the stirring structure to move in the axial direction of the screw during phase change; the shifting structure is provided with a shifting part, the shifting part can make contact with one of the multiple protrusions on the indexing structure, and at the contact position, the shifting part is provided with an inclined face or the protrusions are provided with inclined faces, so that when the shifting structure moves in the direction parallel to the axial direction of the screw, inclined component force is generated, and therefore the shifting part can shift the one of the protrusions. The indexing structure rotates under the condition that the indexing structure is axially fixed, and then the indexing wheel drives the screw rod to rotate; the screw pushes the piston in the axial direction when rotating.

Description

Technical Field

[0001] The utility model relates to the field of mechanical technology, in particular to an infusion drive mechanism and an infusion device. Background Art

[0002] With the development of society and the improvement of living standards, the incidence of metabolic diseases such as diabetes is getting higher and higher. One of the coping methods is to use various infusion devices to inject drugs, such as insulin, into the human body. If the drug infusion device is designed as a patch, which is attached to the human body and continuously performs intelligent infusion, it can bring great convenience to the lives of diabetics.

[0003] In various infusion devices, drugs need to be injected into the human body according to a certain rhythm. At present, motors are mainly used as power sources, but motors are expensive, have low direct driving force, and require gear sets for variable speed transmission. This makes the existing patch-type infusion devices large in size and high in cost, so it is necessary to find a driving method that can take into account the requirements of cost, volume and accuracy.

[0004] Shape memory alloy is a new functional material with deformation recovery ability. Under the action of temperature and load, shape memory alloy can undergo phase change and generate recovery stress, and can return to the initial state after the load is removed. Specifically, under heating, shape memory alloy can shrink autonomously, so it can be used as a power source for various transmission mechanisms. The mainstream shape memory alloy currently used is nickel-titanium alloy. Utility Model Content

[0005] In view of this, the utility model proposes an infusion drive mechanism and an infusion device, which use the force generated by the phase change of the memory alloy as the driving force, and the device has a small size and low cost. The utility model provides the following technical solutions:

[0006] An infusion drive mechanism is used to push a piston inside a medicine reservoir to infuse a medicine solution, and the infusion drive mechanism comprises a screw, a graduation structure, a toggle structure, and a shape memory alloy, wherein: one end of the screw is connected to the piston, the outer peripheral surface of the piston is non-circular and is in sealing contact with the inner surface of the medicine reservoir; the graduation structure is connected to the screw by a thread, and the two are coaxial; the toggle structure is connected to the shape memory alloy, and the shape memory alloy generates displacement when the phase changes, driving the toggle structure to move along the axial direction of the screw; the toggle structure has a toggle part, the graduation structure is connected to the shape memory alloy, and the toggle part is connected to the shape memory alloy. The graduation structure has a plurality of protrusions, and the toggle part can contact one of the plurality of protrusions on the graduation structure, and at the contact position, the toggle part has an inclined surface or the protrusion has an inclined surface, and this inclined surface is not parallel or perpendicular to the axis of the screw, so that when the toggle structure moves in a direction parallel to the axial direction of the screw, an oblique component force is generated, so that the toggle part can toggle one of the protrusions, so that the graduation structure produces a single-direction rotation when the axial direction is fixed, and the rotation of the graduation structure then drives the screw axially forward through the thread; when the screw moves forward, it pushes the piston axially.

[0007] Optionally, the indexing structure further includes a indexing wheel and a nut, the nut is threadedly connected to the screw rod, the indexing wheel is sleeved on the outer circumference of the nut and the two are rigidly fixed.

[0008] Optionally, the toggle structure includes a connecting piece, a slider, a guide rail, and a toggle head, wherein: the connecting piece is fixed on the slider and fixedly connected to the shape memory alloy piece; the slider can slide on the guide rail and cannot rotate relative to the guide rail; the toggle head serves as the toggle part and is fixedly connected to the slider.

[0009] Optionally, the shape memory alloy component is a shape memory alloy wire, the first end of the shape memory alloy wire is fixed at a first fixed point, the second end is fixed at a second fixed point, and the connecting member is fixed at the middle of the shape memory alloy wire, thereby dividing the shape memory alloy wire into two sections; the shape memory alloy wire has a portion parallel to the guide rail, thereby generating a displacement parallel to the guide rail during phase change.

[0010] Optionally, the connecting piece is a crimping sheet, which is crimped to the middle part of the shape memory alloy wire.

[0011] Optionally, it also includes an energy storage element for applying voltage and current to both ends of the shape memory alloy wire between the connecting member and the first fixed point, and applying voltage and current to the shape memory alloy wire between the connecting member and the second fixed point.

[0012] Optionally, the energy storage element is a connector of a battery and a super capacitor, the battery is used to charge the super capacitor, and the super capacitor is used to apply voltage and current to the shape memory alloy wire after charging.

[0013] Optionally, the dividing wheel has two groups of convex teeth, the convex teeth in each group are distributed circumferentially along the outer surface of the dividing wheel and there are gaps between adjacent convex teeth; there is space between the two groups of convex teeth in the axial direction of the dividing wheel, and the convex teeth in this group are axially aligned with the gaps between the convex teeth in the other group.

[0014] Optionally, the side surface of each of the convex teeth close to the axial middle part of the outer surface is the inclined surface, and all of the inclined surfaces are oriented in a first circumferential direction. The paddle portion is a rod-shaped object, and its end portion alternately contacts the inclined surfaces of the two groups of convex teeth and slides on the inclined surfaces when it reciprocates along the axial direction of the dividing wheel from the space, so that the dividing wheel rotates in a second direction, and the second direction is opposite to the first direction; or, the paddle portion is a rod-shaped object, and its end portion has two adjacent inclined surfaces facing the second circumferential direction of the dividing wheel. When this end portion reciprocates along the axial direction of the dividing wheel from the space, the two groups of convex teeth alternately contact the inclined surfaces of the paddle portion and slide on the inclined surfaces, so that the dividing wheel rotates in the second direction.

[0015] Optionally, the piston includes a piston body and a sealant, and the sealant wraps the piston body using a rubber encapsulation process.

[0016] An infusion device comprises a shell, wherein the infusion drive mechanism of the utility model is arranged inside the shell.

[0017] The housing has two limiting parts extending from the inner wall thereof toward the inside of the housing, and the indexing wheel is located between the two limiting parts so as to be axially limited.

[0018] Optionally, the shape memory alloy component is a shape memory alloy wire, the connecting component is fixed to the middle of the shape memory alloy wire, the first end is fixed to a first fixed point, and the second end is fixed to a second fixed point; the first fixed point and the second fixed point are located in the shell.

[0019] According to the technical solution of the utility model, a memory alloy wire is used to drive the toggle head to toggle the indexing wheel, and the piston is pushed through the nut, screw and other components, so that the contraction force of the memory alloy wire during phase change is applied to the piston. The contraction direction of the memory alloy wire is parallel to the screw, so the structure of the infusion drive mechanism in the embodiment of the utility model is relatively compact, which is conducive to the miniaturization of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] For the purpose of illustration and not limitation, the present invention will now be described according to its preferred embodiments, in particular with reference to the accompanying drawings, in which:

[0021] Figure 1 is a schematic diagram of the overall structure of the infusion drive mechanism of the embodiment of the utility model;

[0022] Figure 2 is an overall exploded view of the infusion drive mechanism in the embodiment of the utility model;

[0023] Figure 3 It is a schematic diagram of the structure of the shift block in the embodiment of the utility model;

[0024] Figure 4 It is a schematic diagram of the toggle structure in the embodiment of the utility model;

[0025] Figure 5A and Figure 5B It is a schematic diagram of the crimping of the shape memory alloy member in the embodiment of the utility model;

[0026] Fig. 6A , Figure 6B , Figure 6C It is a schematic diagram of a structure of a dividing wheel in an embodiment of the utility model;

[0027] Figure 7 It is a schematic diagram of the motion relationship between the first toggle head and the convex teeth in the embodiment of the utility model;

[0028] Figure 8 It is a schematic diagram of the component force generated by the inclined surface in the embodiment of the utility model;

[0029] Fig. 9 It is a schematic diagram of the first method of moving the indexing wheel in the embodiment of the utility model;

[0030] Fig.10 It is a schematic diagram of the second method of moving the indexing wheel in the embodiment of the utility model;

[0031] Fig.11 It is a schematic diagram of the motion relationship between the second toggle head and the convex teeth in the embodiment of the utility model;

[0032] Fig.12 It is a schematic diagram of the rotation of the indexing wheel driving the piston to move in the embodiment of the utility model;

[0033] Fig.13 is a schematic diagram of a piston structure in an embodiment of the utility model;

[0034] Fig.14 It is a schematic diagram of a process of the infusion drive control method according to an embodiment of the present invention.

[0035] In the figure:

[0036] 1. Infusion drive mechanism; 2. Shape memory alloy part; 21. First shape memory alloy wire; 22. Second shape memory alloy wire; 3. Shift block; 31. Crimping piece; 32. Slide groove; 33. Shift head; 301. Left inclined surface; 302. Right inclined surface; 4. Guide rail; 5. Indexing wheel; 501. First inclined surface; 502. Second inclined surface; 511. First convex tooth; 512. Second convex tooth; 513. Third convex tooth; 514. Fourth convex tooth; 521. Gap; 522. Support surface; 531. First straight surface; 54. Wheel hole; 53. Convex rib; 6. Nut; 7. Screw; 8. Piston; 81. Piston body; 82. Seal; 9. Medicine reservoir; 01. First fixed point; 02. Second fixed point; 03. First fixed column; 04. Second fixed column. DETAILED DESCRIPTION

[0037] In the implementation of the utility model, the force generated by the memory alloy during phase change drives the shift block to move linearly. When the shift block shifts the dividing wheel axially along the outer circumference of the dividing wheel, one of the two has an inclined surface at the contact position, so that the force of the shift block shifting generates a component force in the tangential direction of the outer circumference of the dividing wheel, and the oblique component force causes the dividing wheel to rotate; the dividing wheel is fixed in the axial direction, and the nut and the screw in the dividing wheel are in a threaded connection relationship. One end of the screw is a piston in the medicine storage container, and the piston is non-circular to limit its rotation. Therefore, when the dividing wheel drives the nut to rotate, the dividing wheel itself cannot move axially, thereby driving the screw. Since the piston at one end of the screw cannot rotate, the screw can only move along its own axial direction when driven, thereby pushing the piston forward or backward. The following is an example of an implementation method for realizing the above functions in conjunction with the accompanying drawings.

[0038] Figure 1 It is a schematic diagram of the overall structure of the infusion drive mechanism of the embodiment of the utility model. Figure 2 FIG. 1 is an overall exploded view of the infusion drive mechanism in the embodiment of the utility model. The infusion drive mechanism can be arranged in an infusion device to drive the piston in the infusion device. Figure 1 and Figure 2 As shown, the infusion drive mechanism 1 includes a shape memory alloy member 2, a shift block 3, a guide rail 4, a dividing wheel 5, a nut 6, and a screw 7. One end of the screw 7 is fixedly connected to a piston 8, which is located in a drug storage container 9 of an infusion device (not shown in its entirety).

[0039] The shift block 3 and the guide rail 4 constitute a shifting structure, wherein the structure of the shift block 3 is as follows: Figure 3 As shown, Figure 3 3 is a schematic diagram of the structure of the shift block in the embodiment of the utility model, wherein the shift block 3 includes a crimping piece 31, a slide groove 32, and a shift head 33. The slide groove 32 is in a rectangular shape, with a crimping piece 31 extending outwardly on one side and a shift head 33 extending outwardly on the opposite side of the side.

[0040] Figure 1 and Figure 2 The partial structure of the shape memory alloy member 2 is shown, and the overall structure of the shape memory alloy member 2 is shown in Figure 4 middle, Figure 4 It is a schematic diagram of the toggle structure in the embodiment of the utility model. The toggle structure includes a toggle block 3 and a guide rail 4. The slide groove 32 is sleeved on the guide rail 4. The former can slide back and forth on the latter, but cannot rotate around the sliding direction.

[0041] The shape memory alloy member 2 specifically adopts a filament structure, a middle portion of which is crimped into a crimping piece 31 made of a metal material. Figure 5A and Figure 5B Schematic diagram of the crimping of shape memory alloy parts in the embodiment of the utility model, wherein Figure 5A The state to be crimped is shown, and the crimping sheet 31 is bent along the direction of the arrow to clamp the shape memory alloy member 2. Figure 5B In this way, on the one hand, the pulling force of the shape memory alloy member 2 can be transmitted to the shift block 3, and on the other hand, the crimping piece 31 of the shift block 3 is also the electrical connection point of the shape memory alloy member 2.

[0042] See also Figure 4 The two ends of the wire-shaped shape memory alloy member 2 are fixed, namely, fixed to the first fixed point 01 and the second fixed point 02 inside the infusion device, so that the shape memory alloy member 2 is divided into two sections, namely, the first shape memory alloy wire 21 and the second shape memory alloy wire 22, as shown in the figure. In order to reduce the size of the product, the two sections of the shape memory alloy wire are respectively bypassed by the first fixed column 03 and the second fixed column 04, which are also fixed objects inside the infusion device.

[0043] The first fixed point 01 and the second fixed point 02 are made of metal. When power is supplied between the crimping piece 31 and the first fixed point 01, the first shape memory alloy wire 21 generates heat due to its own resistance, and after reaching the phase transition temperature, it changes from martensite to austenite, and contracts according to the previously trained state. The second shape memory alloy wire 22 is stretched, and the shift block 3 moves to the lower left of the perspective in the figure. After power is stopped, the first shape memory alloy wire 21 and the second shape memory alloy wire 22 maintain the current position. If the shift block 3 needs to continue to move, power is supplied between the crimping piece 31 and the second fixed point 02, and the second shape memory alloy wire 22 generates heat due to its own resistance, and contracts after reaching the phase transition temperature. The first shape memory alloy wire 21 is stretched, and the shift block 3 moves to the upper right of the perspective in the figure. It can be seen that the shape memory alloy part 2 can make the shift block 3 reciprocate. It can also be seen from the description below that this reciprocating motion can make the screw move axially in a single direction.

[0044] The structure and movement relationship between the indexing wheel 5 and the shifting head 33 are described below. Fig. 6A , Figure 6B , Figure 6C Schematic diagram of a structure of a dividing wheel in an embodiment of the utility model, wherein Fig. 6A For a stereogram, Figure 6B is the front view, Figure 6C is a side view. As shown in the figure, the indexing wheel 5 is wheel-shaped, with a wheel hole 54 in the middle, and two groups of convex teeth distributed circumferentially on the outer surface. Each group of convex teeth is wound around the indexing wheel 5 in a circle, and there is a gap between adjacent convex teeth. For example, there is a gap 521 between the first convex tooth 511 and the second convex tooth 512. The two circles of convex teeth are staggered, that is, one group of convex teeth is aligned with the gap between the other group of convex teeth, for example, the third convex tooth 513 is aligned with the gap 521.

[0045] The side surface of each convex tooth near the axial middle of the outer surface of the indexing wheel 5 is an inclined surface, such as the first inclined surface 501 and the second inclined surface 502. The orientation of all inclined surfaces is consistent. In the embodiment of the utility model, the orientation of the inclined surface is defined as follows: the orientation of the inclined surface is parallel to the tangent of the circumference of the indexing wheel 5 and forms an acute angle with the vertical line away from the inclined surface (that is, this vertical line is a ray). For example, see Figure 6C , from the surface of the first inclined surface 501, a vertical line L1 perpendicular to the first surface extends away from the first inclined surface 501, as shown by the arrow above, and the angle θ between the vertical line L1 and the downward (according to the viewing angle in the figure) tangential indicator line L2 is an acute angle, so the first inclined surface 501 is oriented downward, as shown by the arrow at the lower end of the tangential indicator line L2. The inclined surface here can be a plane or a curved surface with some curvature. If a curved surface is used, the vertical line in the definition of the inclined surface orientation refers to the vertical line of the plane determined by the two parallel straight sides of the curved surface.

[0046] Figure 7 This is a schematic diagram of the first type of movement relationship between the toggle head and the convex teeth in the embodiment of the utility model. For ease of understanding, the convex teeth of the indexing wheel are flattened from a circular shape to a strip shape, and only one pair of convex teeth (filled with oblique lines) is selected for illustration; the toggle head is also simplified and filled with black.

[0047] like Figure 7 As shown in the four stages A, B, C, and D of FIG. 1 , when the first shape memory alloy wire 21 pulls the shift block 3 to move to the left, the shift head hits the inclined surface of the left row of convex teeth, that is, starting from stage A, the inclined surface generates a component force, such as Figure 8 As shown, Figure 8 It is a schematic diagram of the component force generated by the inclined surface of the embodiment of the utility model, wherein when the toggle head 33 moves to the right and presses against the fourth protruding tooth 514, the action force F1 of the toggle head 33 and the supporting force F2 generated by the inclined surface of the fourth protruding tooth serving as the supporting surface 522 are colinear and opposite. Since the supporting force F2 is perpendicular to the supporting surface 522, the direction of F1 is also oblique with respect to the movement direction of the toggle head. F1 can be decomposed into an upward component force F11 and a leftward component force F12.

[0048] According to the previous description, the toggle head can only move left and right but not up and down, and the convex tooth can only rotate but not move left and right. Therefore, the component force F11 generated by the inclined surface pushes the convex tooth to rotate with the entire indexing wheel, which is reflected in Figure 7 The middle is the position of one convex tooth upward, that is, stage B. Figure 7 In the figure, arrows are used near the components to indicate their movement direction. Stage C is similar to stage D. When the second shape memory alloy wire 22 pulls the shift block 3 to move to the right, the shift head hits the inclined surface of the right row of convex teeth. Due to the component force generated by the inclined surface, the convex teeth are pushed to rotate with the entire indexing wheel, and the rotation direction is consistent with the direction of stage A and stage B, which is reflected in Figure 7 In the position of moving up a convex tooth again. In the straight line reciprocating motion of the shifting block so constantly, the indexing wheel 5 rotates continuously, rotating the distance of a convex tooth at each time.

[0049] Fig. 6A , Figure 6B , Figure 6C The indexing wheel 5 and the toggle structure shown are the same as those shown in Fig. 9 middle, Fig. 9 is a schematic diagram of the first method of moving the indexing wheel in the embodiment of the utility model, and Figure 7 According to the above description, Fig. 9 When the toggle head 33 is toggled back and forth left and right according to the viewing angle shown in the figure, the indexing wheel 5 rotates in the direction of the arrow.

[0050] According to the above principle, the protruding teeth and the toggle head may have other structures, as long as one of them has an inclined surface at the contact portion. Fig.10 Schematic diagram of the second method of moving the indexing wheel in the embodiment of the utility model. Fig.11 is a schematic diagram of the motion relationship between the second toggle head and the convex teeth in the embodiment of the utility model, and Fig.10 Correspondingly, the convex teeth being moved are filled with oblique lines, and the moving head is simplified to a black triangle. Fig.10 As shown in FIG. 1 , the inclined planes are located on the toggle head 33, and are two adjacent surfaces of the toggle head 33, namely the left inclined plane 301 and the right inclined plane 302. Obviously, when the toggle head 33 is toggled back and forth, the indexing wheel 5 can also rotate in the direction of the arrow in the figure, thereby cyclically experiencing Fig.11 Stage A to Stage D in the.

[0051] Fig.12The schematic diagram of the piston movement driven by the rotation of the indexing wheel in the embodiment of the utility model. According to the above various ways of turning the indexing wheel 5, the indexing wheel 5 can be rotated unidirectionally in the direction indicated by the curved arrow in the figure. Due to the spiral connection between the nut 6 and the screw 7, the screw 7 cannot rotate because it is connected to the piston 8 of the non-rotating body. Therefore, the screw 7 moves forward in the direction indicated by the straight arrow in the figure, and the screw pushes the piston to push the medicine liquid in the medicine reservoir out for infusion.

[0052] When processing the indexing wheel 5 and the nut 6, the two are processed separately in consideration of the processing difficulty. The indexing wheel 5 is formed by plastic injection molding, which is convenient for forming its convex teeth. The nut 6 is made of copper alloy, which helps it to have both good mechanical strength and low friction coefficient when it and the screw 7 are in spiral motion with each other.

[0053] Fig.13 Schematic diagram of the piston structure in the embodiment of the utility model. Fig.13 As shown, the piston 8 is composed of a piston body 81 and a sealing member 82. The piston body is made of plastic material, and the sealing member is made of rubber material. The sealing member 82 can be independent of the piston body 81, and the two are subsequently assembled to obtain the piston 8; or they can be made into one piece through a rubber coating process. In the embodiment of the utility model, in order to reduce the volume of the product, the width of the piston 8 is made as narrow as possible, so it is preferred to use a rubber coating process to make the piston body 81 and the sealing member 82 into an integrated form.

[0054] The infusion drive mechanism in the embodiment of the utility model can be arranged in the housing of the infusion device, the housing of the infusion device can be designed to a required shape and size, and a limiting structure of the indexing wheel 5 is arranged in the housing, and the realization of the aforementioned first fixed point 01 and the second fixed point 02 and the first fixed column 03 and the second fixed column 04 can be realized by various structures extending from the inner wall of the housing. A battery and related electronic components are also arranged in the housing, including a controller. The controller is used to execute the control method of the infusion drive mechanism in the embodiment of the utility model.

[0055] The toggle head 33 should be able to achieve the required toggle distance when toggling. Figure 8 For example, the toggle head 33 is preferably able to slide across the entire width of the inclined surface and then stop. Because the first shape memory alloy wire 21 or the second shape memory alloy wire 22 generates heat and undergoes phase change when energized, and the resistance changes during the phase change, when the resistance change value of the shape memory alloy wire in the current phase change is measured to be greater than a preset value within a certain period of time, it is considered that the toggle head 33 has completed the toggle of the required distance. The energization time of the shape memory alloy part can be determined. For ease of measurement, the resistance of the shape memory alloy wire can be measured by measuring the current intensity in the shape memory alloy wire under a given voltage.

[0056] Fig.14is a schematic diagram of a process of the infusion drive control method according to an embodiment of the present utility model, such as Fig.14 As shown, two positions A and B are determined on the designed trajectory of piston movement. First, the shape memory alloy part 2 is energized N times at the set energization rate, and then the sensing means is used to measure whether the piston reaches position A. If it has not reached, it is energized N times again and then measured. If it reaches the predetermined position A, a "low liquid alarm" signal is output.

[0057] After the "low liquid medicine alarm" signal is output, the device continues to energize M times at the set energization rate, and then uses the sensing means to measure whether the piston has reached position B. If it has not reached position B, it will be energized M times again and then measured. If it reaches the predetermined position B, the "liquid medicine exhausted" signal is output, requiring the user to replace the device. The control method described above can ensure that the user can sense the lack of liquid medicine in time, while reducing the waste of liquid medicine.

[0058] According to the technical solution of the embodiment of the utility model, a memory alloy wire is used to drive the toggle head to toggle the indexing wheel, and the piston is pushed through the nut, screw and other components, so that the contraction force of the memory alloy wire during phase change is applied to the piston. The contraction direction of the memory alloy wire is parallel to the screw, so the structure of the infusion drive mechanism in the embodiment of the utility model is relatively compact, which is conducive to the miniaturization of the product.

[0059] From the perspective of the entire infusion mechanism, the minimum infusion accuracy is the infusion volume driven by the contraction of the memory alloy piece once; when the memory alloy piece contracts once, it drives the shift block to move a convex tooth position of the indexing wheel, and then the rotation of the indexing wheel drives the screw to move forward a short distance, and this distance pushes the piston to infuse a certain volume of liquid medicine. If the number of convex teeth in a single circle of the indexing wheel is N (N is a natural number), the number of convex teeth in two circles is 2N; the lead of the screw is L, and the cross-sectional area of ​​the medicine chamber of the medicine reservoir is S, then the infusion accuracy P = L × S / 2N. It can be seen that because L can be reduced by using a fine-tooth screw, and N can be increased by increasing the number of convex teeth of the indexing wheel, a fairly high infusion accuracy can be achieved. For example, if U100 insulin is used as an injection solution, L = 0.4mm, S = 125mm, and N = 50, then P is 0.5 cubic millimeters of insulin injected per injection, that is, 0.05 units of insulin, and the accuracy meets medical requirements.

[0060] The above specific implementations do not constitute a limitation on the protection scope of the present utility model. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions may occur depending on design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present utility model shall be included in the protection scope of the present utility model.

Claims

1. An infusion drive mechanism, used to push the piston inside the medicine reservoir to infuse the medicine, characterized in that: The infusion drive mechanism includes a screw, a graduation structure, a toggle structure, and a shape memory alloy part, wherein: One end of the screw is connected to the piston, the outer peripheral surface of the piston is non-circular and is in sealing contact with the inner surface of the medicine reservoir; The indexing structure is connected to the screw rod through threads, and the two are coaxial; The toggle structure is connected to the shape memory alloy part, and the shape memory alloy part generates displacement when the phase changes, driving the toggle structure to move along the axial direction of the screw; The toggle structure has a toggle part, and the dividing structure has multiple protrusions. The toggle part can contact one of the multiple protrusions on the dividing structure, and at the contact position, the toggle part has an inclined surface or the protrusion has an inclined surface, and this inclined surface is not parallel or perpendicular to the axis of the screw, so that when the toggle structure moves parallel to the axial direction of the screw, an oblique component force is generated, so that the toggle part can toggle one of the protrusions, so that the dividing structure produces a single direction of rotation when the axial direction is fixed, and the rotation of the dividing structure then drives the screw axially forward through the thread; when the screw moves forward, it pushes the piston axially.

2. The infusion drive mechanism according to claim 1, characterized in that: The indexing structure also includes a indexing wheel and a nut. The nut is threadedly connected to the screw rod. The indexing wheel is sleeved on the outer peripheral surface of the nut and the two are rigidly fixed.

3. The infusion drive mechanism according to claim 1, characterized in that: The toggle structure includes a connecting piece, a slider, a guide rail, and a toggle head, wherein: The connecting piece is fixed on the slider and is fixedly connected to the shape memory alloy piece; The slider can slide on the guide rail but cannot rotate relative to the guide rail; The toggle head serves as the toggle part and is fixedly connected to the slider.

4. The infusion drive mechanism according to claim 3, characterized in that: The shape memory alloy piece is a shape memory alloy wire, a first end of the shape memory alloy wire is fixed to a first fixed point, a second end of the shape memory alloy wire is fixed to a second fixed point, and the connecting piece is fixed to the middle of the shape memory alloy wire, thereby dividing the shape memory alloy wire into two sections; The shape memory alloy wire has a portion parallel to the guide rail so as to generate a displacement parallel to the guide rail during phase change.

5. The infusion drive mechanism according to claim 4, characterized in that: The connecting piece is a crimping sheet, which is crimped to the middle part of the shape memory alloy wire.

6. The infusion drive mechanism according to claim 4, characterized in that: It also includes an energy storage element for applying voltage and current to both ends of the shape memory alloy wire between the connecting member and the first fixed point, and applying voltage and current to the shape memory alloy wire between the connecting member and the second fixed point.

7. The infusion drive mechanism according to claim 6, characterized in that: The energy storage element is a connection body of a battery and a super capacitor. The battery is used to charge the super capacitor, and the super capacitor is used to apply voltage and current to the shape memory alloy wire after charging.

8. The infusion drive mechanism according to claim 2, characterized in that: The indexing wheel has two groups of convex teeth, the convex teeth in each group are distributed circumferentially along the outer surface of the indexing wheel and there are gaps between adjacent convex teeth; There is a space between the two groups of convex teeth in the axial direction of the indexing wheel, and the convex teeth of one group are aligned with the gaps between the convex teeth of the other group along the axial direction.

9. The infusion drive mechanism according to claim 8, characterized in that: The side surface of each of the convex teeth close to the axial middle of the outer surface is the inclined surface, and all the inclined surfaces are oriented in a first circumferential direction. The shifting portion is a rod-shaped object, and its end portion alternately contacts the inclined surfaces of the two groups of convex teeth and slides on the inclined surfaces when reciprocating along the axial direction of the indexing wheel from the space, so that the indexing wheel rotates in a second direction, and the second direction is opposite to the first direction; Alternatively, the toggle portion is a rod-shaped object, whose end has two adjacent inclined surfaces facing the second circumferential direction of the dividing wheel. When this end reciprocates along the axial direction of the dividing wheel from the space, the two groups of convex teeth alternately contact the inclined surfaces of the toggle portion and slide on the inclined surfaces, causing the dividing wheel to rotate in the second direction.

10. The infusion drive mechanism according to any one of claims 1 to 7, characterized in that: The piston comprises a piston body and a sealant, and the sealant wraps the piston body by using a rubber encapsulation process.

11. An infusion device, comprising a housing, characterized in that: The infusion drive mechanism according to any one of claims 1 to 10 is arranged in the housing.

12. The infusion device according to claim 11, characterized in that The housing has two limiting parts extending from the inner wall thereof toward the inside of the housing, and the indexing wheel is located between the two limiting parts so as to be axially limited.

13. The infusion device according to claim 11 or 12, characterized in that: The shape memory alloy piece is a shape memory alloy wire, the connecting piece is fixed to the middle of the shape memory alloy wire, the first end is fixed to the first fixed point, and the second end is fixed to the second fixed point; The first fixing point and the second fixing point are located inside the housing.

Images