Multi-station film suction printing machine

Abstract

A support assembly of the multi-station film suction printing machine comprises a seat body and a suction printing table assembly installed in the seat body, two sliding rails are symmetrically arranged between the two ends of a framework of the seat body, sliding blocks are arranged on the two sides of the bottom face of the suction printing table assembly, a rack is arranged between the two sliding blocks, and the two sliding blocks are arranged on the two sliding rails in a matched and sliding mode in a sleeved mode. A motor is vertically and fixedly mounted in the middle of the framework to drive the rack; the air supply assembly is installed at one end of an upper end opening of the seat body and comprises an outer cover body and an inner cover body, the inner cover body is connected to a lower end opening of the outer cover body, the lower end opening of the inner cover body is connected with a mirror reflection plate, a plurality of small air supply holes are densely distributed in the mirror reflection plate, and a plurality of heating pipes are installed on the bottom face of the mirror reflection plate side by side. The top plate of the inner cover body is provided with an air supply outlet, and an air supply cylinder is connected between the axial flow fan on the top plate of the outer cover body and the air supply outlet; the suction printing machine can automatically return to the material taking position and the material loading position after finishing transfer printing at the heat transfer printing position, so that the automation degree of heat transfer printing is improved, and the heat transfer printing efficiency is improved.

Description

Technical Field

[0001] The utility model relates to the field of printing machines, in particular to a multi-station film blotting machine. Background Art

[0002] Film thermal transfer machine is a device used to print patterns or texts onto mobile phone cases, keycaps, clothing and other items through thermal transfer technology. When using the film thermal transfer machine, first, use thermal transfer ink to print the pattern or text onto thermal sublimation paper or thermal transfer film, tear off the protective film on the surface of the object to be printed (such as a mobile phone case), and put it on the transfer jig, then place the printed film in the transfer frame, press the transfer frame on the mobile phone case, lock it, push the transfer frame into the film thermal transfer machine, preheat and heat it, so that the pattern or text on the film is transferred to the object, and after the heating is completed, take out the object and cool it down to get the printed finished product. The current film thermal transfer machine usually has a flip-top locking structure. After completing the printing of a batch of substrates, the lid is opened to take out the substrates, and then the substrates are replaced for thermal transfer. The degree of automation and efficiency are relatively low, which is not conducive to mass printing. In addition, the heat generated by the thermal transfer heating tube above is mainly concentrated in the surrounding area of ​​the heating tube, resulting in high energy consumption and uneven heating of different positions of the film, affecting the quality of heating transfer, which needs to be improved. Utility Model Content

[0003] In order to solve the above problems, the utility model provides a multi-station film blotting machine.

[0004] The technical scheme of the utility model is: a multi-station film blotting machine, including a support assembly and an air supply assembly; the support assembly includes a seat body and a blotting table assembly installed in the seat body, two slide rails are symmetrically arranged between the two ends of the frame of the seat body, the frame is formed by welding and fixing square steel pipes, sliders are arranged on both sides of the bottom surface of the blotting table assembly, a rack is arranged between the two sliders, the length of the rack is consistent with the width of the blotting table assembly, the two sliders are matched and slidably sleeved on the two slide rails, the slide rails are circular guide columns, a reduction motor is vertically fixedly installed in the middle of the frame, and a gear meshing with the upper rack is installed on the output shaft of the motor;

[0005] The air supply assembly matches the size of the suction table assembly and is installed at one end of the port on the seat body.

[0006] The air supply component includes an outer housing and an inner housing. The outer housing is of a square structure as a whole. The inner housing is connected to the lower port of the outer housing. A mirror reflector is connected to the lower port of the inner housing. The mirror reflector is in a horizontal state during operation. The mirror reflector is densely provided with a number of air supply small holes. A number of heating tubes are arranged side by side on the bottom surface of the mirror reflector. Pipe clamps are provided on both sides of the mirror reflector. The heating tubes are installed between the pipe clamps at both ends. An air supply port is provided on the top plate of the inner housing, and an axial flow fan is correspondingly installed on the top plate of the outer housing. An air supply cylinder is connected between the axial flow fan and the air supply port.

[0007] Preferably, the imprinting table component includes a vacuum base, a vacuum plate and a pressing edge cover. The vacuum plate is fitted and installed in the accommodation groove inside the vacuum base. A number of transverse wide grooves are evenly provided in the middle of the bottom surface of the vacuum plate. A longitudinal wide groove is provided in the middle of the transverse wide grooves. The transverse wide grooves and the longitudinal wide groove form a vacuum channel with the bottom of the accommodation groove. A number of stepped suction holes are densely provided in both the transverse wide grooves and the longitudinal wide grooves. A connection hole corresponding to the junction of the transverse wide grooves and the longitudinal wide grooves is provided in the middle of the vacuum base. A vacuum joint is installed in the connection hole. The pressing edge cover is hinged to the vacuum base through a hinge. The pressing edge cover is in a square frame shape with a hollow structure in the middle. An upper sealing strip is provided on the bottom surface of the pressing edge cover, and a lower sealing strip is correspondingly provided on the upper surface of the vacuum base. An electric heating plate is fixedly installed on the bottom surface of the vacuum base. The heating plate is a cast aluminum electric heating plate, and the size of the electric heating plate is larger than the size of the vacuum base.

[0008] Preferably, a number of suction cups are evenly provided on the edge part of the electric heating plate, and the suction cups correspond to the bottom surface of the edge part of the pressing edge cover.

[0009] Preferably, a square frame groove is provided on the edge part of the bottom surface of the vacuum plate. The square frame groove is communicated with the transverse wide grooves through connection groove A, and the square frame groove is communicated with the longitudinal wide groove through connection groove B. A number of suction holes are respectively provided along their own length directions in the square frame groove, connection groove A and connection groove B.

[0010] Preferably, a number of support blocks are evenly provided on the upper surface of the vacuum plate through screws. A positioning hole for docking with the suction hole is provided in the middle of the support block, and transition rounded corners are provided at the corners of the support block.

[0011] Preferably, the imprinting table component is installed in a hollow heat insulation housing and is connected to the slide rail through the heat insulation housing. The side surface and the bottom surface of the seat body are both covered with a heat preservation shell. The heat preservation shell is of a sandwich shell structure and is provided with a hollow cavity inside.

[0012] Preferably, the a number of air supply small holes are arranged in rows, the distance between each row of air supply small holes is the same, each row of air supply small holes is vertically aligned with the heating tube, and a thermal resistance sensor is vertically installed in the middle of the mirror reflector.

[0013] Preferably, an L-shaped flange is provided at the edge of the lower port of the inner housing body. A groove structure is formed between the L-shaped flange and the side plate of the inner housing body. At the L-shaped flange, there is an ear plate corresponding to the inner side surface of the inner housing body. A support is fixedly connected to the inner side surface of the inner housing body. The support is of a channel steel structure. The ear plate is connected to the inner side surface of the support. The ear plate is of a folded plate structure. And a cross brace plate is provided at the bottom surface of the support. The cross brace plate supports on the port surface of the inner housing body.

[0014] Preferably, a vertical plate is provided at the lower port of the inner housing body. The inner side surface of the vertical plate is an auxiliary mirror panel. The auxiliary mirror panel and the mirror reflection panel are butted up and down.

[0015] Preferably, the outer housing body includes a housing body and an inner housing body connected to each other. A gap is provided between the housing body and the inner housing body to form a heat insulation cavity. And a cross brace plate is provided at the upper part of the housing body to provide auxiliary support for the axial flow fan through the cross brace plate.

[0016] The beneficial technical effects of the present utility model are as follows:

[0017] (1) The suction machine can drive the suction printing table assembly to reciprocate through the rack and the guide rail mechanism. After the suction printing table assembly moves to the heat transfer position to complete the transfer, it can automatically return to the material taking and loading positions, improving the automation degree of heat transfer and the heat transfer efficiency.

[0018] (2) The fan in the suction machine sends air into the inner housing body through the air supply cylinder. Under the action of the air supply holes at the bottom of the inner housing body, the air is evenly distributed to the surfaces of each heating tube. The heat around the heating tube is evenly sent to the surface of the film below, avoiding heat concentration and improving the uniformity of heating the film. The heating transfer effect is better.

[0019] (3) Mirror reflection plates are provided at the top and side parts of the heating tubes of the suction machine. The heat is reflected downward to the surface of the film through mirror reflection, which can further improve the heat utilization rate and the heating uniformity. Description of the Drawings

[0020] Figure 1 is the three-dimensional structure schematic diagram of the present utility model;

[0021] Figure 2 is Figure 1 the sectional structure schematic diagram in the A-A direction of

[0022] Figure 3 is the three-dimensional structure schematic diagram of the support assembly;

[0023] Figure 4 is Figure 3 the sectional structure schematic diagram in the B-B direction of

[0024] Figure 5It is a three-dimensional structural schematic diagram of the suction printing table assembly;

[0025] Figure 6 It is Figure 5 C-C direction sectional structural schematic diagram of;

[0026] Figure 7 It is Figure 5 D-D direction sectional structural schematic diagram of;

[0027] Figure 8 It is a three-dimensional structural schematic diagram of the vacuum plate;

[0028] Figure 9 It is one of the three-dimensional structural schematic diagrams of the air supply assembly;

[0029] Figure 10 It is Figure 9 E-E direction sectional structural schematic diagram of;

[0030] Figure 11 It is Figure 10 F-F direction sectional structural schematic diagram of;

[0031] Figure 12 It is the three-dimensional structural schematic diagram of the air supply assembly after removing the outer cover

[0032] Figure 13 The second three-dimensional structural schematic diagram of the air supply assembly.

[0033] In the figure, 01. Support assembly, 02. Air supply assembly, 1. Seat body, 11. Heat preservation shell, 12. Travel switch, 13. Trigger baffle, 2. Suction printing table assembly, 21. Vacuum seat, 22. Vacuum plate, 221. Transverse wide groove body, 222. Longitudinal wide groove body, 223. Square groove body, 224. Connecting groove A, 225. Connecting groove B, 226. Suction hole, 227. Vacuum joint, 23. Pressing edge cover, 231. Hinge, 232. Upper sealing strip, 233. Lower sealing strip, 24. Electric heating plate, 25. Suction cup, 26. Support block, 261. Positioning hole, 27. Heat insulation shell, 31. Motor, 32. Gear, 33. Rack, 34. Slide block, 35. Slide rail,

[0034] 4. Outer cover, 41. Axial flow fan, 42. Air supply cylinder, 43. Support, 431. Cross brace plate, 441. Outer shell body, 442. Inner shell body, 45. Heat insulation door, 5. Inner cover, 51. Mirror reflection plate, 511. Air supply small hole, 52. Heating pipe, 53. Inner sleeve, 54. Thermal resistance sensor, 55. L-shaped flanging, 56. Hanging ear plate, 57. Auxiliary mirror panel, 58. Maintenance cover, 59. Air supply port. Specific implementation mode

[0035] Example 1, see the attached drawings of the specification Figures 1-8, a multi-station film blotting machine, including a support assembly 01 and an air supply assembly 02; the support assembly is designed to include a base body 1 and a blotting table assembly 2 installed in the base body 1, the side and bottom surfaces of the base body are covered with an insulation shell 11, and the insulation shell 11 is used as a whole to isolate the heat transfer between the base and the outside world, reduce the heat loss rate, and help reduce energy consumption, two slide rails 35 are symmetrically arranged between the two ends of the frame of the base body 1, sliders 34 are arranged on both sides of the bottom surface of the blotting table assembly 2, and a rack 33 is arranged between the two sliders along the width direction of the blotting table assembly, and the two sliders 34 are matched and slidably mounted on the two slide rails 35, and the blotting table assembly 2 can slide along the two slide rails through the sliders, and a motor 31 is vertically fixedly installed in the middle of the frame, and a gear 32 meshing with the rack 33 above is installed on the output shaft of the motor 31, and the motor 31 drives the gear 32 to rotate, and the gear drive drives the blotting table assembly 2 to slide back and forth along the slide rail 35 through the rack 33. The air supply component 02 matches the size of the suction table component and is installed at one end of the port on the base body 1.

[0036] A travel switch 12 is provided on the frame in the middle of the base body 1, and a trigger baffle 13 corresponding to the travel switch 12 is provided at the bottom of the outer side of the blotting table assembly 2. The baffle is used to trigger the forming switch, and the motor 31 is controlled by the travel switch, thereby controlling the blotting table assembly 2 to stop moving after reaching the thermal transfer station.

[0037] The printing table assembly 2 is designed to include a vacuum seat 21 and a vacuum plate 22. The vacuum plate is matched and installed in a receiving groove inside the vacuum seat. The receiving groove is used to place the printing material. A plurality of transverse wide grooves 221 are evenly arranged in the middle of the bottom surface of the vacuum plate 22. A longitudinal wide groove 222 is arranged in the middle of the transverse wide groove. A negative pressure channel is formed between the transverse wide groove, the longitudinal wide groove and the groove bottom of the receiving groove. A plurality of suction holes 226 are densely distributed in the transverse wide groove 221 and the longitudinal wide groove 222. A plurality of suction holes 226 are densely distributed in the transverse wide groove 221 and the longitudinal wide groove 222. A plurality of suction holes 226 are densely distributed in the middle of the vacuum seat 21. A plurality of suction holes 226 are densely distributed in the transverse wide groove 221 and the longitudinal wide groove 2 ... There is a corresponding connecting hole at the bottom, which is connected to the negative pressure channel. A vacuum joint 227 is installed in the connecting hole, and the vacuum joint is connected to the vacuum pump. The vacuum pump is used to evacuate each negative pressure channel. A plurality of support blocks 26 are evenly provided on the upper surface of the vacuum plate 22 through screws. A positioning hole 261 is provided in the middle of the support block and is connected to the suction hole 226. The substrate is placed on the support block, and the substrate is supported by the support block 26 to avoid deformation due to negative pressure. At the same time, the suction force generated by the positioning hole 261 can adsorb and fix the substrate to keep it in a stable state.

[0038] An electric heating plate 24 is fixedly mounted on the bottom surface of the vacuum seat 21 . The size of the electric heating plate is larger than that of the vacuum seat 21 . The vacuum seat is heated by the electric heating plate 24 .

[0039] The bottom edge part of the vacuum plate 22 is provided with a square frame groove 223. The square frame groove communicates with the transverse wide groove 221 through a connecting groove A 224, and communicates with the longitudinal wide groove 222 through a connecting groove B 225. Suction holes 226 are provided in the square frame groove 223, the connecting groove A 224, and the connecting groove B 225. Each wide groove is concentrated in the support block 26 area, used to make the negative pressure relatively concentrated in the area where the printing substrate is placed, generate a greater adsorption force on the film in this area, improve the suction printing effect. The square frame groove 223 and the relatively narrow grooves such as the connecting grooves are distributed on the edge part, generate an adsorption force on the film at the edge part, and control the overall stability of the film.

[0040] The suction printing table assembly 2 is installed in the hollow heat insulation housing 27, and is connected to the slide rail 35 through the heat insulation housing 27. The heat insulation housing provides heat preservation effect for the suction printing table assembly 2, and together with the heat insulation shell 11 on the base body 1 described above, forms a two-stage heat preservation structure.

[0041] When the suction printing table assembly 2 works, the pressing edge cover 23 is opened upward, each printing substrate is sequentially placed on each support block 26, the film is covered at the upper port of the vacuum seat 21, and then the pressing edge cover 23 is covered downward. Each suction cup 25 sucks and fixes the pressing edge cover 23 tightly. At this time, the sealing strip between the pressing edge cover 23 and the vacuum seat 21 presses the edge part of the film tightly. Each pattern on the film corresponds to each printing substrate respectively. Then the negative pressure pump is started, and vacuum is pumped into the vacuum channel from the vacuum joint 227. Negative pressure is generated on the surface of the vacuum plate 22, and the film is sucked tightly on the surface of the printing substrate. Then the motor 31 is started to drive the gear 32 to rotate, and the gear drive drives the suction printing table assembly 2 to move along the slide rail 35 towards the air supply assembly 02 through the rack 33. After moving in place, the electric heating plate 24 and the air supply assembly 02 are simultaneously turned on for heat transfer printing.

[0042] The suction printing table assembly 2 is provided with a pressing edge cover 23. The pressing edge cover is hinged to the vacuum seat 21 through a hinge 231 and can be turned up and down. An upper sealing strip 232 is provided on the bottom surface of the pressing edge cover, and a lower sealing strip 233 is correspondingly provided on the upper surface of the vacuum seat 21. A plurality of suction cups 25 are evenly provided at the edge part of the electric heating plate 24, and the suction cups correspond to the bottom surface of the edge part of the pressing edge cover 23. When the pressing edge cover 23 is used, it is turned up, then the film is horizontally placed at the upper port of the vacuum seat 21, and then the pressing edge cover 23 is pressed downward. The edge part of the film is pressed tightly between the upper sealing strip 232 and the lower sealing strip 233. At this time, the evenly arranged suction cups 25 adsorb on the bottom surface of the pressing edge cover 23, making the film in a fixed state in the vacuum seat 21, and the film will not have a large displacement due to negative pressure during the vacuum pumping and transfer process, ensuring that the printing substrates at multiple workstations can be vertically aligned with each pattern on the film, and ensuring the heat transfer printing effect.

[0043] Example two, see the attached instructions Figures 9-13, on the basis of the first embodiment, the air supply component is designed to include an outer housing 4 and an inner housing 5 with a certain taper. The inner housing 5 is highly connected to the lower port of the outer housing 4. At the lower port of the inner housing 5, a mirror reflector 51 is connected. A plurality of heating tubes 52 are arranged side by side on the bottom surface of the mirror reflector 51. The spacing between these heating tubes 52 is the same. At the lower port of the inner housing 5, there is a vertical plate. The inner side surface of this vertical plate is an auxiliary mirror panel 57. The auxiliary mirror panel 57 and the mirror reflector 51 are butt-jointed up and down. Mirrors are formed on the top and side of the heating tubes 52 by the mirror reflector 51. The heat is reflected downward to the surface of the film through mirror reflection, avoiding heat concentration in the area of the heating tubes 52 and improving the heat utilization rate and heating uniformity.

[0044] At the edge of the lower port of the inner housing 5, there is an L-shaped flange 55. At this L-shaped flange 55, there is an ear plate 56 corresponding to the inner side surface of the inner housing 5. The anti-deformation strength of the inner housing 55 is improved through this L-shaped flange 55. The inner side surface of the inner housing 5 is fixedly connected with a support 43. The ear plate 56 is connected to the inner side surface of the support 43. And at the bottom surface of the support 43, there is a cross brace 431. The cross brace 431 supports on the port surface of the inner housing 5. The cross brace 431 can play a role in assisting the support of the inner housing 5 and improving its stability when installed in the outer housing 4.

[0045] The outer housing 4 includes an outer shell 441 and an inner shell 442 that are connected to each other. A gap is provided between the outer shell 441 and the inner shell 442 to form a heat insulation cavity. This design enables the outer housing 4 to have a heat preservation and insulation effect. Combined with the inner housing 5, it can effectively avoid the loss of heat from the heating tubes 52.

[0046] On one side surface of the outer housing 4, there is a heat insulation door 45. On the inner housing 5 at the corresponding position of the heat insulation door 45, there is a maintenance cover 58. After the heat insulation door 45 is opened, the maintenance personnel can face the maintenance cover directly, and maintenance operations can be conveniently carried out through this maintenance cover.

[0047] A number of air supply small holes 511 are densely arranged on the mirror reflector 51. On the top plate of the inner housing 5, there is an air supply port 59. On the top plate of the outer housing 4, an axial flow fan 41 is correspondingly installed. A ventilation tube 42 is connected between the axial flow fan 41 and the air supply port 59. The air is sent into the ventilation tube 42 through the axial flow fan 41, and then enters the interior of the inner housing 5 from the ventilation tube 42. The air supply small holes 511 evenly distribute the air to the surfaces of each heating tube 52. The heat around the heating tubes 52 is evenly sent to the lower film surface, avoiding heat concentration and improving the heat utilization efficiency.

[0048] A thermal resistance sensor 54 is vertically installed in the middle of the mirror reflector 51. The heating temperature is monitored in real time through this thermal resistance sensor 54, and the constancy of the heating temperature is ensured through signal feedback.

[0049] A number of air supply small holes 511 are arranged in rows, and the air supply small holes 511 in each row are directly opposite to the heating pipe 52 up and down. In this way, air can be directly sent from the air supply small holes 511 to the surface of the heating pipe 52, and the air supply efficiency to the heating pipe 52 is higher, which is more conducive to sending heat from the surface of the heating pipe 52 downward to the surface of the film. An inner sleeve 53 is connected at the air supply port 59, and the inner sleeve 53 is fitted and installed at the lower port of the air supply cylinder 42. This sleeve connection structure is conducive to the assembly, disassembly and maintenance of the inner cover body 5, and improves the flexibility and convenience of use.

Claims

1. A multi-station film blotting machine, characterized by: It includes a support assembly and an air supply assembly; The support assembly includes a seat body and a blotting table assembly installed in the seat body. Two slide rails are symmetrically arranged between the two ends of the frame of the seat body. Slide blocks are arranged on both sides of the bottom surface of the blotting table assembly. A rack is arranged between the two slide blocks. The two slide blocks are matched and slidably mounted on the two slide rails. A motor is vertically fixedly installed in the middle of the frame. A gear meshing with the rack above is installed on the output shaft of the motor. The air supply assembly matches the size of the suction table assembly and is installed at one end of the port on the seat body. The air supply assembly includes an outer cover body and an inner cover body. The inner cover body is connected to the lower port of the outer cover body. A mirror reflector is connected to the lower port of the inner cover body. The mirror reflector is densely covered with a number of air supply holes. A number of heating tubes are installed side by side on the bottom surface of the mirror reflector. An air supply port is arranged on the top plate of the inner cover body. An axial flow fan is correspondingly installed on the top plate of the outer cover body. An air supply tube is connected between the axial flow fan and the air supply port.

2. A multi-station film blotting machine according to claim 1, characterized in that: The printing table assembly includes a vacuum seat, a vacuum plate and a pressure edge cover. The vacuum plate is matched and installed in the accommodating groove inside the vacuum seat. A plurality of transverse wide grooves are evenly arranged in the middle of the bottom surface of the vacuum plate. A longitudinal wide groove is arranged in the middle of the transverse wide groove. A plurality of suction holes are densely distributed in the transverse wide groove and the longitudinal wide groove. A connecting hole corresponding to the intersection of the transverse wide groove and the longitudinal wide groove is arranged in the middle of the vacuum seat. A vacuum joint is installed in the connecting hole. The pressure edge cover is hinged to the vacuum seat through a hinge. An upper sealing strip is arranged on the bottom surface of the pressure edge cover. A lower sealing strip is arranged correspondingly on the upper surface of the vacuum seat. An electric heating plate is fixedly installed on the bottom surface of the vacuum seat. The size of the electric heating plate is larger than that of the vacuum seat.

3. A multi-station film blotting machine according to claim 2, characterized in that: A plurality of suction cups are evenly arranged on the edge of the electric heating plate, and the suction cups correspond to the bottom surface of the edge of the edge pressing cover.

4. The multi-station film blotting machine according to claim 2, characterized in that: A square frame groove body is provided at the bottom edge of the vacuum plate. The square frame groove body is connected to the transverse wide groove body through a connecting groove A, and the square frame groove body is connected to the longitudinal wide groove body through a connecting groove B. Suction holes are provided in the square frame groove body, the connecting groove A and the connecting groove B.

5. The multi-station film blotting machine according to claim 2, characterized in that: A plurality of support blocks are evenly arranged on the upper surface of the vacuum plate through screws, and a positioning hole that is connected to the air suction hole is arranged in the middle of the support block.

6. The multi-station film blotter according to claim 1, characterized in that: The blotting table assembly is installed in a hollow heat-insulating shell and connected to the slide rail through the heat-insulating shell. The side and bottom surfaces of the seat body are covered with heat-insulating shells.

7. The multi-station film blotter according to claim 1, characterized in that: The plurality of air supply holes are arranged in rows, the air supply holes in each row are directly opposite to the heating tube up and down, and a thermal resistance sensor is vertically installed in the middle of the mirror reflection plate.

8. The multi-station film blotter according to claim 1, characterized in that: An L-shaped flange is provided on the edge of the lower port of the inner cover body, and a hanging ear plate corresponding to the inner side of the inner cover body is provided at the L-shaped flange. A support is fixedly connected to the inner side of the inner cover body, and the hanging ear plate is connected to the inner side of the support. A cross brace is provided on the bottom surface of the support, and the cross brace is supported on the port surface of the inner cover body.

9. The multi-station film blotter according to claim 1, characterized in that: A vertical plate is provided at the lower end of the inner cover body, the inner side surface of the vertical plate is an auxiliary mirror plate, and the auxiliary mirror plate and the mirror reflection plate are butted up and down.

10. The multi-station film blotter according to claim 1, characterized in that: The outer cover comprises an outer shell and an inner shell which are connected to each other, and a gap is provided between the outer shell and the inner shell to form a heat insulation cavity.

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