Extrusion mechanism and 3D printer

Abstract

The utility model provides a kind of extrusion mechanism and 3D printer, belong to 3D printing technical field.Extrusion mechanism includes frame body, driving wheel and at least two extrusion wheels;Frame body is equipped with installation space;Driving wheel is at least partially housed in installation space, and is rotatably connected with frame body;At least two extrusion wheels are housed in installation space, are all drivingly connected with driving wheel and interval is formed between two adjacent extrusion wheels to form the conveying channel of consumable.The extrusion mechanism provided by the utility model is drivingly connected with extrusion wheel and driving wheel, to drive extrusion wheel synchronous rotation by driving wheel, to form the conveying channel of consumable between two adjacent extrusion wheels, to make extrusion wheel provide extrusion force and thrust to consumable in conveying channel in the process of rotation, guarantee the fluency and stability of conveying consumable, to guarantee printing quality.

Description

Technical Field

[0001] This utility model relates to the field of 3D printing technology, and in particular to an extrusion mechanism and a 3D printer. Background Technology

[0002] Existing extrusion technology relies on the friction between the extrusion wheel's cylindrical surface and the filament to propel the filament. This results in a small contact area and low friction. At high-speed feeding and when higher extrusion force is required, slippage and poor mechanism stability are common. Increasing friction by reducing the filament channel size would lead to severe filament deformation, preventing it from entering the heating channel. Utility Model Content

[0003] In view of this, the purpose of this utility model is to overcome the shortcomings of the prior art and provide an extrusion mechanism and a 3D printer.

[0004] In a first aspect, this utility model provides an extrusion mechanism, comprising:

[0005] The frame has installation space.

[0006] The drive wheel is at least partially housed in the mounting space and rotatably connected to the frame.

[0007] At least two extrusion wheels are housed in the installation space, both of which are drivenly connected to the drive wheel, and a consumable delivery channel is formed between two adjacent extrusion wheels.

[0008] In some embodiments, the at least two extrusion wheels include a first extrusion wheel and a second extrusion wheel, the opposing walls of the first extrusion wheel and the second extrusion wheel being parallel to each other and forming the delivery channel of the consumable.

[0009] In some embodiments, the first extrusion wheel and the second extrusion wheel are coaxially arranged and rotatably connected to the frame.

[0010] In some embodiments, the extrusion mechanism includes a tensioning mechanism connected to the frame and rotatably connected to the first extrusion wheel and the second extrusion wheel, the tensioning mechanism being able to adjust the distance between the first extrusion wheel and the second extrusion wheel.

[0011] In some embodiments, the tensioning mechanism includes a bolt and a tensioning element, the tensioning element being disposed on the side of the first extrusion wheel opposite to the second extrusion wheel;

[0012] One end of the bolt passes through the second extrusion wheel and the first extrusion wheel in sequence and is threadedly connected to the frame. One end of the tensioner abuts against the first extrusion wheel, and the other end of the tensioner abuts against the frame.

[0013] In some embodiments, the extrusion mechanism includes a drive unit, the output shaft of which is coaxially connected to the drive wheel.

[0014] In some embodiments, the frame includes a first connector and a second connector, wherein the second connector has a connecting platform on the side facing the first connector;

[0015] The first connector is connected to the second connector via the connecting platform to define the installation space between the first connector and the second connector.

[0016] In some embodiments, the connecting platform is provided with a guide channel that is at least partially housed within the conveying channel.

[0017] In some embodiments, the extrusion wheel has a friction surface on the side facing the conveying channel;

[0018] The friction surface includes a plurality of racks, which are arranged at equal intervals, with one end of each rack facing the axis of the extrusion wheel;

[0019] And / or the friction surface includes a plurality of protrusions, and the plurality of protrusions are arranged in an array.

[0020] Secondly, this utility model provides a 3D printer, including a nozzle, a melting mechanism, and the aforementioned extrusion mechanism.

[0021] The embodiments of this utility model have the following advantages: The extrusion mechanism provided in this application drives the extrusion wheel to rotate synchronously through the drive wheel, and forms a material conveying channel between two adjacent extrusion wheels. This allows the extrusion wheel to provide extrusion force and thrust to the material in the conveying channel during rotation. This not only increases the contact area between the material and the extrusion wheel and reduces slippage between the material and the extrusion wheel, but also improves the pushing force on the material, ensuring the smoothness and stability of material conveying, thereby ensuring printing quality.

[0022] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This diagram shows a structural schematic of an extrusion mechanism according to some embodiments of the present invention;

[0025] Figure 2 An exploded view of an extrusion mechanism provided by some embodiments of the present invention is shown;

[0026] Figure 3 An exploded view of an extrusion mechanism provided by some embodiments of the present invention is shown below;

[0027] Figure 4 This diagram shows a structural schematic of an extrusion mechanism provided by some embodiments of the present invention from another perspective;

[0028] Figure 5 It shows Figure 4 Sectional view of section AA;

[0029] Figure 6 It shows Figure 4 Sectional view of the middle BB section;

[0030] Figure 7 It shows Figure 4 A cross-sectional view of the central CC section.

[0031] Explanation of key component symbols:

[0032] 100 - Frame; 110 - Installation space; 120 - First connector; 130 - Second connector; 140 - Connecting platform; 141 - Relief groove; 142 - Guide channel; 200 - Drive wheel; 300 - Extrusion wheel; 310 - First extrusion wheel; 320 - Second extrusion wheel; 330 - Friction surface; 331 - Rack; 400 - Conveying channel; 500 - Tensioning mechanism; 510 - Tensioning element; 520 - Bolt; 600 - Drive device; 700 - First bearing; 800 - Second bearing; 900 - First connecting part; 1000 - Second connecting part; 910 - First connecting ring; 920 - Groove; 1010 - Second connecting ring; 1020 - Boss. Detailed Implementation

[0033] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0034] It should be noted that when an element is said to be "fixed" to another element, it can be directly on the other element or there may be an intervening element. When an element is said to be "connected" to another element, it can be directly connected to the other element or there may be an intervening element. Conversely, when an element is said to be "directly" on another element, there is no intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0035] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0036] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the template description is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0038] like Figures 1 to 5 As shown, some embodiments of this utility model provide an extrusion mechanism, mainly applied in the field of 3D printing technology, to ensure the stability of material extrusion during the printing process, thereby improving printing quality.

[0039] The extrusion mechanism includes a frame 100, a drive wheel 200, and at least two extrusion wheels 300.

[0040] The frame 100 is provided with an installation space 110. The drive wheel 200 is at least partially housed in the installation space 110 and is rotatably connected to the frame 100. That is, the drive wheel 200 can rotate relative to the frame 100. The frame 100 can provide support and limit the drive wheel 200 to ensure the stability of the drive wheel 200 in the installation space 110.

[0041] It is understood that in some embodiments, the drive wheel 200 is partially housed in the mounting space 110. In other embodiments, the drive wheel 200 is completely housed in the mounting space 110, and the position of the drive wheel 200 in the mounting space 110 can be specifically set according to the actual situation.

[0042] At least two extrusion wheels 300 are housed in the installation space 110. Each extrusion wheel 300 is connected to the drive wheel 200, meaning that the drive wheel 200 can drive the extrusion wheels 300 to rotate synchronously during rotation. A consumable conveying channel 400 is formed between two adjacent extrusion wheels 300. Understandably, during the rotation of the extrusion wheels 300, consumables are drawn into the conveying channel 400. Friction is generated between the consumables and the inner wall of the extrusion wheels 300. This friction provides a squeezing and propelling effect on the consumables passing through the conveying channel 400, ensuring the smoothness and stability of consumable conveying.

[0043] It is understandable that the number of extrusion wheels 300 can be any number of two or more values, and can be set according to the actual situation.

[0044] For example, in some embodiments, there are two extrusion wheels 300, which are spaced apart to form a consumable delivery channel 400.

[0045] In other embodiments, there are three extrusion wheels 300, which are spaced apart to form two consumable conveying channels 400. That is, in this embodiment, consumables can be conveyed through two conveying channels 400 to improve the conveying efficiency of consumables.

[0046] In some other embodiments, the number of extrusion wheels 300 is N, where N is a positive integer greater than three, and the N extrusion wheels 300 are spaced apart to form N-1 consumable conveying channels 400, so as to further improve the conveying efficiency of consumables and increase the diversity of consumable conveying by the extrusion mechanism to meet the different needs of users during use.

[0047] like Figures 1 to 7As shown, in some embodiments, at least two extrusion wheels 300 include a first extrusion wheel 310 and a second extrusion wheel 320. The opposing walls of the first extrusion wheel 310 and the second extrusion wheel 320 are parallel to each other and are spaced apart to form a consumable conveying channel 400, so as to ensure the consistency of the width of the conveying channel 400, thereby ensuring the stability of the extrusion pressure and friction on the consumable during the rotation of the first extrusion wheel 310 and the second extrusion wheel 320, thereby ensuring the stability and smoothness of conveying the consumable.

[0048] like Figures 4 to 6 As shown, in some embodiments, the first extrusion wheel 310 and the second extrusion wheel 320 are coaxially arranged and rotatably connected to the frame 100. Both the first extrusion wheel 310 and the second extrusion wheel 320 are connected to the drive wheel 200 for transmission, so that the frame 100 provides support and fixation for the first extrusion wheel 310 and the second extrusion wheel 320, ensuring the stability of the first extrusion wheel 310 and the second extrusion wheel 320 during rotation relative to the frame 100. That is, the drive wheel 200 can drive the first extrusion wheel 310 and the second extrusion wheel 320 to rotate synchronously during rotation.

[0049] like Figure 5 As shown, in some embodiments, the extrusion mechanism includes a tensioning mechanism 500, which is connected to the frame 100 and rotatably connected to the first extrusion wheel 310 and the second extrusion wheel 320. That is, the first extrusion wheel 310 and the second extrusion wheel 320 can rotate relative to the tensioning mechanism 500 to ensure the stability of the synchronous rotation of the first extrusion wheel 310 and the second extrusion wheel 320 driven by the drive wheel 200 during rotation.

[0050] In this embodiment, the tensioning mechanism 500 can adjust the distance between the first extrusion wheel 310 and the second extrusion wheel 320. It can be understood that since the first extrusion wheel 310 and the second extrusion wheel 320 form a conveying channel 400 at an interval, the width of the conveying channel 400 is adjusted by adjusting the distance between the first extrusion wheel 310 and the second extrusion wheel 320 through the tensioning mechanism 500.

[0051] like Figure 5 As shown, in some embodiments, the tensioning mechanism 500 includes a bolt and a tensioning element 510, which is disposed on the side of the first extrusion wheel 310 away from the second extrusion wheel 320.

[0052] One end of the bolt passes through the second extrusion wheel 320 and the first extrusion wheel 310 in sequence and is threadedly connected to the frame 100. One end of the tensioning member 510 abuts against the first extrusion wheel 310, and the other end of the tensioning member 510 abuts against the frame 100, so as to provide elastic force to the first extrusion wheel 310 through the tensioning member 510, thereby increasing the friction between the consumable and the first extrusion wheel 310 and the second extrusion wheel 320, thereby ensuring that the consumable can be extruded normally.

[0053] In some embodiments, the bolt, the first extrusion wheel 310, and the second extrusion wheel 320 are coaxially connected, and the first extrusion wheel 310 and the second extrusion wheel 320 are rotatably connected to the bolt, so as to provide support for the first extrusion wheel 310 and the second extrusion wheel 320 through the bolt, so as to ensure the stability of the first extrusion wheel 310 and the second extrusion wheel 320 during rotation relative to the frame 100.

[0054] It should be noted that the tensioning element 510 can be a spring, a torsion spring, or elastic rubber. In this embodiment, the elastic element is a spring.

[0055] In this embodiment, a first bearing 700 is provided between the first extrusion wheel 310 and the bolt 520. The first bearing 700 is sleeved on the bolt 520 to reduce the frictional force during the rotation of the first extrusion wheel 310 relative to the bolt 520 and ensure the smoothness of the rotation of the first extrusion wheel 310 relative to the bolt 520.

[0056] In addition, a second bearing 800 is provided between the second extrusion wheel 320 and the bolt 520. The second bearing 800 is sleeved on the bolt 520 to reduce the frictional force during the rotation of the second extrusion wheel 320 relative to the bolt 520 and ensure the smooth rotation of the second extrusion wheel 320 relative to the bolt 520.

[0057] like Figures 1 to 7 As shown, in some embodiments, the extrusion mechanism includes a drive device 600, the output shaft of which is coaxially connected to the drive wheel 200. During the operation of the drive device 600, the output shaft drives the drive wheel 200 to rotate coaxially, thereby driving the extrusion wheel 300 to rotate synchronously through the drive wheel 200, ensuring the stability of the extrusion wheel 300 during rotation.

[0058] like Figures 1 to 6 As shown, in some embodiments, the frame 100 includes a first connector 120 and a second connector 130. The connection method between the first connector 120 and the second connector 130 includes any one of snap-fit, adhesive, or bolt connection, which can be specifically set according to the actual situation.

[0059] The second connector 130 has a connecting platform 140 on the side facing the first connector 120, and the connecting platform 140 is located on the edge of the second connector 130.

[0060] In this embodiment, the first connector 120 is connected to the second connector 130 via the connecting platform 140, so that the connecting platform 140 provides support, spacing and fixation between the first connector 120 and the second connector 130, thereby defining an installation space 110 between the first connector 120 and the second connector 130.

[0061] The first connector 120 and the second connector 130 can be one of a connecting plate, a connecting platform 140, or a connecting frame, and can be specifically set according to the actual situation.

[0062] like Figure 4 and Figure 7 As shown, in some embodiments, the connecting platform 140 is provided with a guide channel 142, which is at least partially housed within the transport channel 400. The guide channel 142 provides guidance and restraint for the consumables, ensuring smooth and stable movement of the consumables within it. It is understood that in some embodiments, the guide channel 142 is partially housed within the transport channel 400. In other embodiments, the guide channel 142 is completely housed within the transport channel 400.

[0063] Understandably, since the guide channel 142 is at least partially housed within the transport channel 400, that is, the inner walls of the first extrusion wheel 310 and the second extrusion wheel 320 are at least partially formed in the channel wall of the guide channel 142, the filament passing through the guide channel 142 can contact the inner walls of the first extrusion wheel 310 and the second extrusion wheel 320 to increase the friction with the filament. This enhances the extrusion force and thrust on the filament during the rotation of the first extrusion wheel 310 and the second extrusion wheel 320, preventing slippage between the first extrusion wheel 310 and the second extrusion wheel 320 and the filament, and also increasing the thrust on the filament, ensuring the smoothness and stability of the filament's movement in the transport channel 400, thereby guaranteeing print quality.

[0064] like Figure 2 As shown, in this embodiment, the connecting platform 140 is provided with a relief groove 141 on the side facing the extrusion wheel 300 to provide space for the extrusion wheel 300 and prevent the extrusion wheel 300 from contacting the connecting platform 140 during rotation. The guide channel 142 passes through the relief groove 141, so that a part of the extrusion wheel 300 can be accommodated in the relief groove 141 and contact a part of the consumable material passing through the guide channel 142. During the rotation of the extrusion wheel 300, the consumable material is squeezed out by friction, thereby ensuring the smoothness and stability of the consumable material movement in the conveying channel 400.

[0065] like Figure 2 and Figure 3As shown, in some embodiments, the extrusion wheel 300 is provided with a friction surface 330 on the side facing the conveying channel 400, so that the consumable entering the conveying channel 400 can contact the friction surface 330. The friction surface 330 increases the friction with the consumable, thereby increasing the extrusion force and thrust on the consumable during the rotation of the first extrusion wheel 310 and the second extrusion wheel 320. This not only avoids slippage between the extrusion wheel 300 and the consumable, but also increases the thrust on the consumable, ensuring the smoothness and stability of the consumable's movement in the conveying channel 400, thereby ensuring print quality.

[0066] In addition, such as Figure 2 and Figure 3 As shown, in some embodiments of this utility model, the friction surface 330 includes a plurality of racks 331, which are arranged at equal intervals. By arranging the plurality of racks 331 at equal intervals, the consistency of the frictional force exerted on the consumable by any two adjacent racks 331 is ensured, and the uniformity of the force on the consumable between the first extrusion wheel 310 and the second extrusion wheel 320 is ensured.

[0067] One end of the rack 331 faces the axis of the extrusion wheel 300, so that when the rack 331 contacts the consumable, the included angle between them can be between 45° and 90°, thereby increasing the friction between the rack 331 and the consumable. It can be understood that by reducing the distance between two adjacent racks 331, the density of the racks 331 is increased, thereby effectively increasing the contact area between the rack 331 and the consumable per unit area, increasing the friction between the rack 331 and the consumable per unit area, thereby increasing the thrust of the friction surface 330 on the consumable, and improving the stability and smoothness of the consumable's flow in the conveying channel 400.

[0068] In other embodiments, the friction surface 330 includes a plurality of protrusions arranged in an array, and the distance between two adjacent protrusions is equal to ensure the consistency of the frictional force exerted on the consumable by any two adjacent protrusions, and to ensure the uniformity of the force on the consumable between the first extrusion wheel 310 and the second extrusion wheel 320.

[0069] The distance between two adjacent protrusions can be set according to the actual situation. It can be understood that by reducing the distance between two adjacent protrusions, the density of the protrusions can be increased, thereby effectively increasing the contact area between the protrusions and the consumables per unit area, increasing the friction between the protrusions and the consumables per unit area, thereby increasing the thrust of the friction surface 330 on the consumables, and improving the stability and smoothness of the consumables' movement in the conveying channel 400.

[0070] like Figure 2 and Figure 3As shown, in this embodiment, the first extrusion wheel 310 has a friction surface 330 on the side facing the second extrusion wheel 320, and / or the second extrusion wheel 320 has a friction surface 330 on the side facing the first extrusion wheel 310.

[0071] It is understood that in some embodiments, the first extrusion wheel 310 has a friction surface 330 on the side facing the second extrusion wheel 320, or the second extrusion wheel 320 has a friction surface 330 on the side facing the first extrusion wheel 310. In other embodiments, the first extrusion wheel 310 has a friction surface 330 on the side facing the second extrusion wheel 320, and the second extrusion wheel 320 has a friction surface 330 on the side facing the first extrusion wheel 310.

[0072] In this embodiment, friction surfaces 330 are provided on both the first extrusion wheel 310 and the second extrusion wheel 320. This means that the consumable material passing through the conveying channel 400 can contact the friction surfaces 330, thereby increasing the friction between the consumable material and the friction surface 330. This enhances the extrusion force and thrust on the consumable material during the rotation of the first extrusion wheel 310 and the second extrusion wheel 320. This not only prevents slippage between the first extrusion wheel 310 and the second extrusion wheel 320 and the consumable material, but also increases the thrust on the consumable material, ensuring the smoothness and stability of the consumable material conveying, thus guaranteeing printing quality.

[0073] It should be noted that the friction surface 330 on the first extrusion wheel 310 and the friction surface 330 on the second extrusion wheel 320 are parallel to each other to ensure that the friction force between the first extrusion wheel 310 and the consumable is equal to the friction force between the second extrusion wheel 320 and the consumable, so as to ensure the stability of the consumable during its movement in the conveying channel 400 and avoid pulling on the consumable.

[0074] like Figure 2 and Figure 3 As shown, in some embodiments of this utility model, the first extrusion wheel 310 is provided with a first connecting part 900 on the side facing the second extrusion wheel 320, and the second extrusion wheel 320 is provided with a second connecting part 1000 on the side facing the first extrusion wheel 310. The first connecting part 900 and the second connecting part 1000 are connected to connect the first extrusion wheel 310 and the second extrusion wheel 320, so that the first extrusion wheel 310 and the second extrusion wheel 320 can rotate synchronously to ensure the stability and smoothness of the extrusion of consumables.

[0075] Specifically, in this embodiment, the first connecting part 900 is a first connecting ring 910, and the inner wall of the first connecting ring 910 is provided with a groove 920. The second connecting part 1000 is a second connecting ring 1010, and the outer wall of the second connecting ring 1010 is provided with a boss 1020. The first connecting ring 910 is sleeved on the second connecting ring 1010, the boss 1020 is received in the groove 920, and the outer wall of the boss 1020 contacts the groove wall of the groove 920. The outer wall of the second connecting ring 1010 contacts the inner wall of the first connecting ring 910, ensuring the stability of the connection between the first connecting part 900 and the second connecting part 1000 and preventing shaking. This connects the first connecting part 900 and the second connecting part 1000, ensuring the stability of the connection between the first extrusion wheel 310 and the second extrusion wheel 320.

[0076] In addition, some embodiments of this utility model provide a 3D printer, including a nozzle, a melting mechanism, and an extrusion mechanism as described in any of the above embodiments. The extrusion mechanism and the nozzle are connected through the melting mechanism, that is, the extrusion mechanism feeds the consumable into the melting mechanism, and after melting, it is extruded by the nozzle for printing.

[0077] It should be noted that the 3D printer provided in this embodiment has the beneficial effects of the extrusion mechanism in any of the above embodiments, which will not be described in detail here.

[0078] In all examples shown and described herein, any specific values ​​should be interpreted as merely exemplary and not as limitations; therefore, other examples of exemplary embodiments may have different values.

[0079] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0080] The embodiments described above are merely examples of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of this utility model. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these modifications and improvements all fall within the protection scope of this utility model.

Claims

1. An extrusion mechanism, characterized in that, include: The frame has installation space. The drive wheel is at least partially housed in the mounting space and rotatably connected to the frame. At least two extrusion wheels are housed in the installation space, both of which are drivenly connected to the drive wheel, and a consumable conveying channel is formed between two adjacent extrusion wheels; The extrusion wheel has a friction surface on one side facing the conveying channel, and the friction surface is used to contact the consumables entering the conveying channel.

2. The extrusion mechanism according to claim 1, characterized in that, The at least two extrusion wheels include a first extrusion wheel and a second extrusion wheel, with the opposing walls of the first extrusion wheel and the second extrusion wheel being parallel to each other and forming the conveying channel of the consumable.

3. The extrusion mechanism according to claim 2, characterized in that, The first extrusion wheel and the second extrusion wheel are coaxially arranged and rotatably connected to the frame.

4. The extrusion mechanism according to claim 2, characterized in that, The extrusion mechanism includes a tensioning mechanism, which is connected to the frame and rotatably connected to the first extrusion wheel and the second extrusion wheel. The tensioning mechanism is capable of adjusting the distance between the first extrusion wheel and the second extrusion wheel.

5. The extrusion mechanism according to claim 4, characterized in that, The tensioning mechanism includes a bolt and a tensioning element, the tensioning element being disposed on the side of the first extrusion wheel opposite to the second extrusion wheel; One end of the bolt passes through the second extrusion wheel and the first extrusion wheel in sequence and is threadedly connected to the frame. One end of the tensioner abuts against the first extrusion wheel, and the other end of the tensioner abuts against the frame.

6. The extrusion mechanism according to any one of claims 1 to 5, characterized in that, The extrusion mechanism includes a drive unit, the output shaft of which is coaxially connected to the drive wheel.

7. The extrusion mechanism according to claim 6, characterized in that, The frame includes a first connector and a second connector, and the second connector has a connecting platform on the side facing the first connector; The first connector is connected to the second connector via the connecting platform to define the installation space between the first connector and the second connector.

8. The extrusion mechanism according to claim 7, characterized in that, The connecting platform is provided with a guide channel, which is at least partially contained within the conveying channel.

9. The extrusion mechanism according to claim 1, characterized in that, The friction surface includes a plurality of racks, which are arranged at equal intervals, with one end of each rack facing the axis of the extrusion wheel; And / or the friction surface includes a plurality of protrusions, and the plurality of protrusions are arranged in an array.

10. A 3D printer, characterized in that, It includes a nozzle, a melting mechanism, and an extrusion mechanism as described in any one of claims 1 to 9.

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