CN111605197A

CN111605197A - Automatic material changing device and automatic material changing method for 3D printer

Info

Publication number: CN111605197A
Application number: CN202010544244.1A
Authority: CN
Inventors: 刘辉林; 唐京科; 敖丹军; 陈春; 严罗林
Original assignee: Shenzhen Chuangxiang 3D Technology Co Ltd
Current assignee: Shenzhen Chuangxiang 3D Technology Co Ltd
Priority date: 2020-06-15
Filing date: 2020-06-15
Publication date: 2020-09-01
Also published as: WO2021253791A1

Abstract

The invention discloses an automatic material changing device and an automatic material changing method for a 3D printer, wherein the device comprises an extrusion mechanism and a switching mechanism; the extruding mechanism comprises a driving wheel, a first driven wheel set, a second driven wheel set, a first rotating clamp, a second rotating clamp and an extension spring, one end of each of the first rotating clamp and the second rotating clamp is hinged with the cover body, and the other end of each of the first rotating clamp and the second rotating clamp is connected through the extension spring; the switching mechanism comprises a switching rod which is rotatably connected with the extrusion base and a switching handle which is fixedly connected with the switching rod; one end of the first rotating clamp close to the extension spring is fixedly connected with a first limiting column, and one end of the second rotating clamp close to the extension spring is fixedly connected with a second limiting column; when the switching handle is in an initial state, two ends of the switching rod are respectively abutted to the first limiting column and the second limiting column, so that the first driven wheel set and the second driven wheel set are both separated from the driving wheel. The invention has high automation degree, improves the working efficiency and saves the labor cost.

Description

Automatic material changing device and automatic material changing method for 3D printer

Technical Field

The invention relates to the field of 3D printing, in particular to an automatic material changing device and an automatic material changing method for a 3D printer.

Background

In the 3D printing process, an extruder is used for driving the material wires to enter the spray head, and then the molten material wires are extruded from the nozzle for printing. But the condition that the stock silk runs out can appear printing on the way, needs operating personnel to stick in for a long time and carries out manual reloading beside the printer, if do not in time change the charging tray, prints and will fail, has greatly reduced work efficiency and stock silk utilization ratio.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides an automatic material changing device and an automatic material changing method for a 3D printer.

In order to achieve the purpose, the invention adopts the following technical scheme: the automatic material changing device of the 3D printer comprises a cover body, an extrusion mechanism, a switching mechanism and a motor; an installation cavity is arranged in the cover body, and the extruding mechanism and the switching mechanism are installed in the installation cavity; the extrusion mechanism comprises a driving wheel, a first driven wheel set, a second driven wheel set, a first rotating clamp, a second rotating clamp and an extension spring; one ends of the first rotating clamp and the second rotating clamp are hinged with the cover body, and the other ends of the first rotating clamp and the second rotating clamp are connected through the extension spring; the driving wheel is positioned between the first rotating clamp and the second rotating clamp; an output shaft of the motor is connected with the driving wheel; the switching mechanism comprises a switching rod which is rotatably connected with the cover body and a switching handle which is fixedly connected with the switching rod; one end of the first rotating clamp close to the extension spring is fixedly connected with a first limiting column, and one end of the second rotating clamp close to the extension spring is fixedly connected with a second limiting column; the switching handle is to being close to when first driven wheelset rotates, first driven wheelset with the action wheel meshing, the switching handle is to being close to when second driven wheelset rotates, the second driven wheelset with the action wheel meshing.

The further technical scheme is as follows: the first driven wheel set comprises a first switching gear and a first extrusion bearing; the first switching gear is arranged above the first extrusion bearing, and a first bulge is arranged on the first switching gear; the second driven wheel set comprises a second switching gear and a second extrusion bearing; the second switching gear is arranged above the second extrusion bearing, and a second bulge is arranged on the second switching gear.

The further technical scheme is as follows: one end of the switching rod is also provided with a first blocking part, and the other end of the switching rod is also provided with a second blocking part.

The further technical scheme is as follows: one end of the switching rod is provided with a first inwards concave arc-shaped surface, and the first inwards concave arc-shaped surface forms a guide surface which is abutted against the first limiting column; the other end of the switching rod is provided with a second concave arc-shaped surface, and the second concave arc-shaped surface forms a guide surface which is abutted against the second limiting column.

The further technical scheme is as follows: the cover body comprises an extrusion base and an extrusion cover connected with the extrusion base; the extruding base is provided with the installation cavity, the through hole is located on the extruding base, the motor is fixed at the bottom of the extruding base, and an output shaft of the motor penetrates through the through hole to be connected with the driving wheel.

The further technical scheme is as follows: first switching gear all is equipped with first extension spring post on extruding the base, second switching gear all is equipped with second extension spring post on extruding the base, be connected with first spring between first switching gear and two first extension spring posts of extruding the base, second switching gear and two second spring posts of extruding the base are connected with the second spring between.

The further technical scheme is as follows: the device also comprises a first feeding pipe, a second feeding pipe, a first discharging pipe and a second discharging pipe; first inlet pipe and first discharging pipe are located respectively first driven wheelset and the middle both ends of action wheel, second inlet pipe and second discharging pipe are located respectively the second is driven wheelset and the middle both ends of action wheel.

The further technical scheme is as follows: the extrusion base is provided with a first fixing hole for fixing the first feeding pipe, a second fixing hole for fixing the first discharging pipe, a third fixing hole for fixing the second feeding pipe and a fourth fixing hole for fixing the second discharging pipe; the first fixing hole and the second fixing hole are positioned on the same axis, and the third fixing hole and the fourth fixing hole are positioned on the same axis; the mounting cavity is also internally provided with a supporting plate for supporting the first feeding pipe and the second feeding pipe, and the supporting plate is provided with a first supporting hole with the diameter corresponding to that of the first feeding pipe and a second supporting hole with the diameter corresponding to that of the second feeding pipe; the first support hole and the second support hole are arranged side by side.

The further technical scheme is as follows: the motor mounting plate is also included; the motor mounting plate is fixed in extrude the bottom of base, the motor with motor mounting plate fixed connection.

An automatic material changing method adopting the automatic material changing device of the 3D printer comprises the following steps:

monitoring a feeding channel which is working;

judging whether the feeding channel which is working is in a state of material breaking or not;

if so, the motor is controlled to drive the driving wheel to rotate reversely so as to withdraw the residual threads in the feeding channel, and the driven wheel set corresponding to the feeding channel is separated from the driving wheel under the action force of the driven wheel set corresponding to the feeding channel on the switching rod, so that the driven wheel set corresponding to the other feeding channel is meshed with the driving wheel.

Compared with the prior art, the invention has the beneficial effects that: according to the automatic material changing device of the 3D printer, the driven wheel set and the driving wheel are controlled to be meshed and separated through the switching handle, the automatic switching of the feeding channel is realized by utilizing the reverse rotation of the motor, so that the automatic material changing is completed, manual monitoring and material changing are not needed, the automation degree is high, the working efficiency is improved, and the labor cost is saved.

The foregoing description is only an overview of the technical solutions of the present invention, and in order to make the technical means of the present invention more clearly understood, the present invention may be implemented according to the content of the description, and in order to make the above and other objects, features, and advantages of the present invention more apparent, the following detailed description will be given of preferred embodiments.

Drawings

FIG. 1 is an assembly diagram of an embodiment of an automatic material changing device of a 3D printer according to the present invention;

FIG. 2 is an exploded view of an embodiment of an automatic material changing device of a 3D printer according to the present invention;

FIG. 3 is a schematic view of an installation structure of components in an installation cavity in an embodiment of the automatic material changing device of the 3D printer according to the invention;

FIG. 4 is a schematic view of an installation structure of components in an installation cavity in an embodiment of the automatic material changing device of the 3D printer according to the invention (an extrusion base is not shown);

FIG. 5 is a schematic view of a mounting structure of a sub-component inside a mounting cavity in an embodiment of the automatic material changing device of the 3D printer;

FIG. 6 is a schematic structural diagram of an extrusion base in an embodiment of an automatic material changing device of a 3D printer according to the present invention;

FIG. 7 is a schematic structural diagram of a switching mechanism in an embodiment of an automatic material changing device of a 3D printer according to the invention;

fig. 8 is a schematic structural diagram of a first driven wheel set in an embodiment of an automatic material changing device of a 3D printer according to the invention.

Reference numerals

1. A cover body; 11. extruding the cover; 12. extruding the base; 121. a mounting cavity; 122. a first tension spring column; 1221. a first spring; 123. a second tension spring column; 1231. a second spring; 124. a first fixing hole; 125. a second fixing hole; 126. a third fixing hole; 127. a fourth fixing hole; 128. a support plate; 1281. a first support hole; 1282. a second support hole; 129. a through hole; 2. a motor mounting plate; 3. a motor; 4. a first rotating clamp; 41. a first driven wheel set; 411. a first switching gear; 412. a first protrusion; 413. a first extrusion bearing; 42. a first limit post; 43. an extension spring; 5. a second rotating clamp; 51. a second driven wheel set; 52. a second limit post; 6. a switching mechanism; 61. a switch lever; 611. a first inner concave arc surface; 612. a first blocking portion; 613. a second concave arc-shaped surface; 614. a second blocking portion; 62. switching a handle; 7. a driving wheel; 8. a first feed tube; 9. a first discharge pipe; 10. a second feed tube; 20. a second discharge pipe; 30. a first feed channel; 40. a second feed channel.

Detailed Description

In order to more fully understand the technical content of the present invention, the technical solution of the present invention will be further described and illustrated with reference to the following specific embodiments, but not limited thereto.

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations and positional relationships based on those shown in the drawings, and are used only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be considered as limiting the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating 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 the present invention, "a plurality" means two or more unless specifically defined otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be connected or detachably connected or integrated; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

In the description herein, references to the description of the term "one embodiment," some embodiments, "" an example, "" a specific example, "" or "some examples," or the like, mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above should not be understood to necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples described in this specification can be combined and combined by one skilled in the art.

Example one

The invention provides an automatic material changing device of a 3D printer, please refer to FIGS. 1-5 and 8, the device comprises a cover body 1, an extrusion mechanism, a switching mechanism 6, a motor 3, a first feeding pipe 8, a second feeding pipe 10, a first discharging pipe 9 and a second discharging pipe 20; the cover body 1 comprises an extrusion base 12 and an extrusion cover 11 connected with the extrusion base 12; the extrusion base 12 is provided with a mounting cavity 121, and the extrusion mechanism, the switching mechanism 6, the feeding pipe and the discharging pipe are all mounted in the mounting cavity 121; the extruding mechanism comprises a driving wheel 7, a first driven wheel set 41, a second driven wheel set 51, a first rotating clamp 4, a second rotating clamp 5 and an extension spring 43; one ends of the first rotating clamp 4 and the second rotating clamp 5 are hinged with the extrusion base 12, and the other ends of the first rotating clamp 4 and the second rotating clamp 5 are connected through an extension spring 43; one end of the first rotating clamp 4 close to the extension spring 43 is fixedly connected with a first limit column 42, and one end of the second rotating clamp 5 close to the extension spring 43 is fixedly connected with a second limit column 52; the driving wheel 7 is positioned between the first rotating clamp 4 and the second rotating clamp 5, the extrusion base 12 is provided with a through hole 129, and an output shaft of the motor 3 positioned below the extrusion base 12 passes through the through hole 129 to be connected with the driving wheel 7; the first driven wheel group 41 includes a first switching gear 411 and a first extrusion bearing 413; the first switching gear 411 is arranged above the first extrusion bearing 413, and a first bulge 412 is arranged on the first switching gear 411; the second driven wheel set 51 comprises a second switching gear and a second extrusion bearing; the second switching gear is arranged above the second extrusion bearing, and a second bulge is arranged on the second switching gear; the switching mechanism 6 comprises a switching rod 61 which is rotatably connected with the extrusion base 12 and a switching handle 62 which is fixedly connected with the switching rod 61; one end of the switching rod 61 is provided with a first blocking part 612, and the other end of the switching rod 61 is also provided with a second blocking part 614; one end of the switching rod 61 is further provided with a first concave arc surface 611, and the first concave arc surface 611 forms a guide surface abutting against the first limit column 42; the other end of the switch rod 61 is further provided with a second concave arc surface 613, and the second concave arc surface 613 forms a guide surface abutting against the second limit post 52. When the first switching gear 41 rotates reversely, the first protrusion 412 contacts with the first blocking portion 612, and the switching handle 62 rotates in a direction away from the first driven wheel set 41, the first concave arc-shaped surface 611 of the switching rod 61 contacts with the first limiting column 42, so as to prevent the first rotating clamp 4 from approaching in a direction towards the driving wheel 7, so that the first switching gear 411 is separated from the driving wheel 7, and the second switching gear is engaged with the driving wheel 7; when the second switching gear rotates reversely, the second protrusion will contact with the second blocking portion 614, and the switching handle 62 rotates in a direction away from the second driven wheel set 51, and the second concave arc 613 of the switching rod 61 contacts with the second limiting 52 column for preventing the second rotating clamp from approaching to the driving wheel direction, so that the second switching gear is separated from the driving wheel 7, and the first switching gear 411 is engaged with the driving wheel 7. The first switching gear 411 and the extrusion base 12 are both provided with a first tension spring column 122, the second switching gear and the extrusion base 12 are both provided with a second tension spring column 123, a first spring 1221 is connected between the first switching gear 411 and the two first tension spring columns 122 of the extrusion base 12, and a second spring 1231 is connected between the second switching gear and the two second spring 1231 columns of the extrusion base 12; when the switching handle 62 is in an initial state, two ends of the switching rod 61 respectively abut against the first limiting column 42 and the second limiting column 52, so that the first driven wheel set 41 and the second driven wheel set 51 are both separated from the driving wheel 7, a separation space between the first extrusion bearing 413 of the first driven wheel set 41 and the driving wheel 7 forms a first feeding channel 30, the first feeding pipe 8 and the first discharging pipe 9 are respectively located at two ends of the first feeding channel 30, a separation space between the second extrusion bearing and the driving wheel 7 forms a second feeding channel 40, and the second feeding pipe 10 and the second discharging pipe 20 are respectively located at two ends of the second feeding channel 40; when the switching handle 62 rotates close to the first driven wheel set 41, the first switching gear 411 of the first driven wheel set 41 is meshed with the driving wheel 7, and when the switching handle 62 rotates close to the second driven wheel set 51, the second switching gear of the second driven wheel set 51 is meshed with the driving wheel 7; can be rotated in a forward direction or in a reverse direction by controlling the output shaft of the motor 3. Specifically, the principle that this device can realize automatic reloading is as follows:

one end of each of the first rotating clamp 4 and the second rotating clamp 5 is hinged to the extruding base 12, and the other end is connected through the extension spring 43, so that the extension spring 43 can provide a pulling force for drawing the first rotating clamp 4 and the second rotating clamp 5 together, when the switching handle 62 is at an initial position (when the switching handle 62 is not rotated leftwards or rightwards), two ends of the switching rod 61 are respectively abutted to the first limiting column 42 and the second limiting column 52 respectively arranged on the first rotating clamp 4 and the second rotating clamp 5, due to the abutting action, the switching rod 61 can counterbalance the pulling force generated by the extension spring 43, so that the first driven wheel set 41 and the second driven wheel set 51 are both separated from the driving wheel 7 when the switching handle 62 is at the initial position, thereby a first feeding channel is formed between the first extruding bearing 413 of the first driven wheel set 41 and the driving wheel 7, a second feeding channel is formed between the second extruding bearing of the second driven wheel set 51 and the driving wheel 7, when feeding, the material silk is added into the feeding pipe and penetrates into the feeding channel to complete feeding.

After the two feeding channels are fed, the 3D printing process may be started, specifically, for example, when the first feeding channel 30 starts to work, the switching handle 62 needs to be rotated to rotate the switching rod 61 toward the second position-limiting post 42, after the rotation, the end of the switching rod 61 that is originally abutted against the first position-limiting post 42 no longer forms an abutment (at this time, the second position-limiting post 52 and the other end of the switching rod 61 still maintain an abutment relationship), but the two ends are separated, and after the separation, due to the pulling force of the tension spring 43, the distance between the first extrusion bearing 413 of the first driven wheel set 41 and the driving wheel 7 is reduced, the driving wheel 7 is driven by the motor 3 to rotate in the forward direction, the driving wheel 7 drives the first extrusion bearing 413 of the first driven wheel set 41 to move (because the first extrusion bearing 413 has two inner and outer rings, the first switching gear 411 of the first driven wheel set 41 and the inner ring of the first extrusion bearing 413 are installed together, the actual driving pulley 7 moves the outer race of the first extrusion bearing 413 of the first driven pulley group 41, and therefore the switching gear is not moved. And because the end part of the switching rod 61 is an inward concave arc surface, the switching rod 61 cannot block the forward rotation of the first driven wheel set 41), and the material wire is extruded to the first discharge pipe 9 and is extruded by the nozzle after being heated.

If it is detected that the first feeding channel 30 is short of material, the motor 3 drives the driving wheel 7 to rotate reversely, when the driving wheel 7 drives the first extruding bearing 413 of the first driven wheel set 41 to rotate reversely, the filament remained in the first feeding channel 30 is ejected (since no filament exists between the first extruding bearing 413 of the first driven wheel set 41 and the driving wheel after the filament is ejected, the first switching gear 411 of the first driven wheel set 41 is engaged with the driving wheel 7), after the filament is ejected, the driving wheel 7 drives the first switching gear 411 to move, when the first switching gear 411 moves, the first protrusion 412 on the first switching gear 411 contacts with the first blocking portion 612 on the switching rod 61, the first protrusion 412 forces the switching rod 61 to move in a direction away from the first driven wheel set 41, the switching rod 61 abuts against the first limit column 42, and the switching rod 61 gives a certain resistance to the first limit column 52, prevent first driven wheelset 41 to be close to action wheel 7 to make first change gear 411 and action wheel 7 separation, the distance of second driven wheelset 51 and action wheel 7 reduces simultaneously, has realized automatic reloading with this, does not need artificial control, reloading, and degree of automation is high, has promoted work efficiency, has practiced thrift the human cost. In addition, there are many ways to detect the material shortage of the feeding channel, for example, a sensor may be disposed in the feeding channel to detect whether the feeding channel is short of material, and when the sensor detects that the material is short of material, the output shaft of the motor 3 is controlled to rotate reversely.

In addition, the first spring 1221 connected between the two first tension spring columns 122 and the second tension spring 1231 connected between the two second tension spring columns 123 can give a switching gear restraining force to the driven wheel when the driven wheel is separated from the driving wheel 7, so that the driven wheel and the driving wheel 7 can be kept in a separated state.

Referring to fig. 6, the extruding base 12 is provided with a first fixing hole 124 for fixing the first feeding pipe 8, a second fixing hole 125 for fixing the first discharging pipe 9, a third fixing hole 126 for fixing the second feeding pipe 10, and a fourth fixing hole 127 for fixing the second discharging pipe 20; the first fixing hole 124 and the second fixing hole 125 are located on the same axis, and the third fixing hole 126 and the fourth fixing hole 127 are located on the same axis. A supporting plate 128 for supporting the first feeding pipe 8 and the second feeding pipe 10 is further arranged in the mounting cavity 121, and a first supporting hole 1281 corresponding to the diameter of the first feeding pipe 8 and a second supporting hole 1282 corresponding to the diameter of the second feeding pipe 10 are formed in the supporting plate 128; the first support hole 1281 and the second support hole 1282 are arranged side by side.

In some embodiments, for example, in the present embodiment, please refer to fig. 1 and 2, the apparatus further includes a motor mounting plate 2; the motor mounting plate 2 is fixed at the bottom of the extrusion base 12, and the motor 3 is fixedly connected with the motor mounting plate 2.

Example two

The invention also provides an automatic material changing method of the automatic material changing device of the 3D printer, the method adopts the automatic material changing device of the 3D printer in the first embodiment, and concretely, the method comprises the following steps:

the first step is as follows: monitoring a feeding channel which is working;

the second step is that: judging whether the feeding channel which is working is in a state of material breaking or not;

the third step: if so, driving the driving wheel to rotate reversely by controlling the motor so as to withdraw the residual threads in the feeding channel, and separating the driven wheel set corresponding to the feeding channel from the driving wheel under the action of the driven wheel corresponding to the feeding channel on the switching rod so as to reduce the distance between the driven wheel corresponding to the other feeding channel and the driving wheel; if not, the first step is continuously executed.

Through monitoring the pay-off passageway, when the condition of taking place disconnected material, utilize the counter rotation of motor, realize the automatic switch-over of pay-off passageway to accomplish automatic reloading, do not need artificial control, reloading, degree of automation is high, has promoted work efficiency, has practiced thrift the human cost.

The technical contents of the present invention are further illustrated by the examples only for the convenience of the reader, but the embodiments of the present invention are not limited thereto, and any technical extension or re-creation based on the present invention is protected by the present invention. The protection scope of the invention is subject to the claims.

Claims

The automatic material changing device of the 3D printer is characterized by comprising a cover body, an extrusion mechanism, a switching mechanism and a motor; an installation cavity is arranged in the cover body, and the extruding mechanism and the switching mechanism are installed in the installation cavity; the extrusion mechanism comprises a driving wheel, a first driven wheel set, a second driven wheel set, a first rotating clamp, a second rotating clamp and an extension spring; one ends of the first rotating clamp and the second rotating clamp are hinged with the cover body, and the other ends of the first rotating clamp and the second rotating clamp are connected through the extension spring; the driving wheel is positioned between the first rotating clamp and the second rotating clamp; an output shaft of the motor is connected with the driving wheel; the switching mechanism comprises a switching rod which is rotatably connected with the cover body and a switching handle which is fixedly connected with the switching rod; one end of the first rotating clamp close to the extension spring is fixedly connected with a first limiting column, and one end of the second rotating clamp close to the extension spring is fixedly connected with a second limiting column; the switching handle is to being close to when first driven wheelset rotates, first driven wheelset with the action wheel meshing, the switching handle is to being close to when second driven wheelset rotates, the second driven wheelset with the action wheel meshing.
2. The 3D printer auto feed changer of claim 1, wherein the first driven wheel set comprises a first switching gear and a first extrusion bearing; the first switching gear is arranged above the first extrusion bearing, and a first bulge is arranged on the first switching gear; the second driven wheel set comprises a second switching gear and a second extrusion bearing; the second switching gear is arranged above the second extrusion bearing, and a second bulge is arranged on the second switching gear.
3. The automatic material changing device for the 3D printer according to claim 1, wherein one end of the switching rod is further provided with a first blocking portion, and the other end of the switching rod is further provided with a second blocking portion.
4. The automatic material changing device of the 3D printer according to claim 3, wherein one end of the switching rod is provided with a first concave arc-shaped surface, and the first concave arc-shaped surface forms a guide surface which is abutted with the first limiting column; the other end of the switching rod is provided with a second concave arc-shaped surface, and the second concave arc-shaped surface forms a guide surface which is abutted against the second limiting column.
5. The automatic reloading device of 3D printer as claimed in claim 2, wherein said cover body comprises an extrusion base, and an extrusion cover connected with the extrusion base; the extruding base is provided with the installation cavity, the through hole is located on the extruding base, the motor is fixed at the bottom of the extruding base, and an output shaft of the motor penetrates through the through hole to be connected with the driving wheel.
6. The automatic material changing device of the 3D printer according to claim 5, wherein the first switching gear and the extrusion base are both provided with a first tension spring column, the second switching gear and the extrusion base are both provided with a second tension spring column, a first spring is connected between the first switching gear and two first tension spring columns of the extrusion base, and a second spring is connected between the second switching gear and two second tension spring columns of the extrusion base.
7. The automatic refueling device for 3D printers according to any one of claims 1 to 6, further comprising a first feeding pipe, a second feeding pipe, a first discharging pipe, and a second discharging pipe; first inlet pipe and first discharging pipe are located respectively first driven wheelset and the middle both ends of action wheel, second inlet pipe and second discharging pipe are located respectively the second is driven wheelset and the middle both ends of action wheel.
8. The automatic material changing device for the 3D printer according to claim 7, wherein the extrusion base is provided with a first fixing hole for fixing the first feeding pipe, a second fixing hole for fixing the first discharging pipe, a third fixing hole for fixing the second feeding pipe, and a fourth fixing hole for fixing the second discharging pipe; the first fixing hole and the second fixing hole are positioned on the same axis, and the third fixing hole and the fourth fixing hole are positioned on the same axis; the mounting cavity is also internally provided with a supporting plate for supporting the first feeding pipe and the second feeding pipe, and the supporting plate is provided with a first supporting hole with the diameter corresponding to that of the first feeding pipe and a second supporting hole with the diameter corresponding to that of the second feeding pipe; the first support hole and the second support hole are arranged side by side.
9. The automatic reloading device of 3D printer according to claim 8, characterized in that it also comprises a motor mounting plate; the motor mounting plate is fixed in extrude the bottom of base, the motor with motor mounting plate fixed connection.
10. An automatic refueling method using the automatic refueling device of the 3D printer according to any one of claims 1 to 9, wherein the method comprises the following steps:

monitoring a feeding channel which is working;

judging whether the feeding channel which is working is in a state of material breaking or not;

if so, the motor is controlled to drive the driving wheel to rotate reversely so as to withdraw the residual threads in the feeding channel, and the driven wheel set corresponding to the feeding channel is separated from the driving wheel under the action force of the driven wheel set corresponding to the feeding channel on the switching rod, so that the driven wheel set corresponding to the other feeding channel is meshed with the driving wheel.