Hot air pen capable of recovering heat

Abstract

The invention provides a hot air pen capable of recovering heat. The hot air pen comprises an outer shell with an opening in the front end face, an inner shell with openings in the front end face and the rear end face, a fan arranged close to the rear end of the inner shell and an electric heating element arranged close to the front end of the inner shell. The air suction end of the fan opens towards the rear end of the inner shell, and the air outlet end opens towards the front end of the inner shell. An air inlet channel is formed between the outer shell and the inner shell; a front end opening of the outer shell is an air inlet; an air outlet channel is formed in the inner shell, a front end opening of the inner shell is an air outlet, and a rear end opening is an air suction opening. Due to the fact that the air inlet and the air outlet are located on the same side, hot air blown to a welding point and diffused after being heated can be sucked into the air inlet again through the fan, heat recovery is achieved, the waste heat utilization rate is increased, the adverse effect of the hot air on the working environment is reduced, and elements around the welding point are prevented from being heated and damaged. In addition, due to the fact that the reasonable heat insulation design is adopted, an operator can directly hold the front end of the pen body shell to work, the use safety is high, and operation is efficient.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic processing, and particularly relates to a hot air pen with heat recovery function. Background Art

[0002] In the electronic processing industry, a hot air gun is a commonly used welding tool for operations such as component welding, removal, and circuit board repair. Its working principle is to use an internal electric heating element to generate heat, and a fan blows hot air towards the component to be welded or removed for heating. Currently, most mainstream hot air guns on the market adopt a structure with the air inlet and outlet located at both ends. The air inlet is at the tail of the gun body to inhale cold air, and the air outlet is at the front end of the gun body to output hot air. The electric heating element heats the air between them, and the fan is located behind the electric heating element to blow out the hot air. However, this structure has obvious disadvantages:

[0003] 1. The hot air at the air outlet cannot be heat recovered

[0004] With the air inlet and outlet located at both ends, the hot air after heating is directly dissipated into the environment after being blown out, unable to be recycled, resulting in energy waste and possibly having an adverse impact on the working environment. When welding temperature-sensitive electronic components, the dissipation of hot air will lead to unstable welding quality.

[0005] 2. The hot air will spread after hitting the circuit board, causing overheating of the surrounding area

[0006] The hot air blown out by the hot air gun spreads rapidly after contacting the circuit board, causing unnecessary heating of the components around the welding point and possibly leading to overheating and damage of the surrounding components. This problem is particularly prominent in the welding of high-density and high-precision circuit boards. Existing solutions rely on operators to precisely control the distance and angle of the hot air gun, increasing the operation difficulty and complexity, and it is difficult to completely avoid the influence of heat on the surrounding components.

[0007] 3. It is difficult to cool down the gun body

[0008] The electric heating element is set at the front and close to the air outlet. The cold air enters the gun body from the rear air inlet and is heated at the front of the gun body, resulting in an increase in the temperature of the gun body and increasing the risk of scalding to the operator. To avoid scalding, a handle is generally set at the rear of the gun body, but the distance between the handle and the air outlet is relatively far, making it difficult for the operator to precisely control, increasing the operation difficulty. In addition, the high temperature of the gun body will also affect the performance and service life of the hot air gun, and the existing heat dissipation methods have limited effects and cannot effectively solve the problem of overheating of the gun body. Summary of the Invention

[0009] The purpose of the present invention is to provide a hot air pen with heat recovery function to effectively solve the problems that the existing hot air guns have significant disadvantages in aspects such as heat recovery and gun body cooling.

[0010] The technical solution of the present invention is realized as follows:

[0011] A heat - recoverable hot - air pen according to the present invention includes: a housing configured as a shell with an opening on the front end face and sealed on other faces; an inner shell configured as a shell with openings on both the front end face and the rear end face and sealed on other faces; a fan disposed in the inner shell and near the rear end face, the suction end of the fan facing the rear - end opening of the inner shell, the air - outlet end of the fan facing the front - end opening of the inner shell, and the fan being used to provide the power for air flow; a heating element disposed in the inner shell and near the front end face for heating air; the inner diameter of the housing is larger than the outer diameter of the inner shell so that an air - inlet channel is formed between the housing and the inner shell, and the front - end opening of the housing is configured as an air inlet; the interior of the inner shell is configured as an air - outlet channel, the front - end opening of the inner shell is configured as an air outlet, and the rear - end opening of the inner shell is configured as a suction port.

[0012] In some embodiments, the air outlet protrudes forward beyond the edge of the air inlet.

[0013] In some embodiments, a circuit board and an electrical connection structure are provided inside the rear end of the housing, and there is a gap between the rear end face of the inner shell and the bottom of the circuit board.

[0014] In some embodiments, the present invention further includes a heat - insulating sleeve with openings on both the front end face and the rear end face. The heat - insulating sleeve is disposed inside the housing and near the air inlet. The heat - insulating sleeve is cooperatively connected with the inner wall of the housing. The inner diameter of the heat - insulating sleeve is larger than the outer diameter of the inner shell so that the air - inlet channel is formed between the heat - insulating sleeve and the inner shell, and the air inlet is configured as the front - end opening of the heat - insulating sleeve.

[0015] Further, there is a gap between the heat - insulating sleeve and the housing, and the inner wall of the housing is provided with a plurality of rib plates extending into the gap to cooperatively connect with the outer wall of the heat - insulating sleeve.

[0016] In some embodiments, the inner shell includes an electric - heating - element housing, an air - duct housing, and a fan housing from the front end to the rear end. The heating element is installed in the electric - heating - element housing. The air - duct housing is a wind - collecting air duct that is narrow at the front and wide at the rear. The fan is installed in the fan housing. The electric - heating - element housing is connected to the air - duct housing, and the air - duct housing is connected to the fan housing by means of plug - in connection.

[0017] Further, the fan housing includes a motor base and a fan - blade sleeve. The front end of the motor base is plugged into the air - duct housing, the rear end of the motor base is sleeved with the fan - blade sleeve, and the suction port is opened on the rear end face of the fan - blade sleeve.

[0018] Furthermore, the fan includes fan blades and a motor. The motor is installed in the motor base, and the motor is located at the central position of the motor base. An air duct is formed between the motor and the inner wall of the motor base. The fan blades are installed in the fan blade sleeve.

[0019] In some embodiments, a connecting column extends backward from the outer wall of the rear end face of the fan blade sleeve. A circuit board is provided inside the rear end of the housing, and the circuit board is fixedly connected to the connecting column so that a gap is formed between the circuit board and the air suction port.

[0020] In some embodiments, the housing includes a first housing and a second housing. The first housing includes an annular portion at the front end, a semi-cylindrical cavity portion in the middle, and an end cover portion at the rear end. The inner housing is inserted into the housing from the cavity portion and fixed by screws. The second housing is designed to be coverable at the open end of the cavity portion to form a semi-cylindrical housing with an overall cylindrical shape together with the cavity portion. The connection between the second housing and the first housing is a sealed connection.

[0021] The beneficial effects of the present invention are as follows:

[0022] 1. Heat recovery and energy saving: The air inlet and the air outlet are on the same side. The hot air that is blown to the welding point and diffuses can be sucked in again by the fan from the air inlet, realizing heat recovery, improving the utilization rate of waste heat, reducing energy consumption, and reducing the adverse impact of hot air on the working environment.

[0023] 2. Protecting surrounding components: The air inlet can recover the diffused hot air, and the components around the welding point will not be damaged by heat, especially suitable for high-density and high-precision circuit board welding, improving the welding quality and stability.

[0024] 3. Reducing the temperature of the gun body and improving the operating performance: By setting the housing and the inner housing to form an annular air duct, after the heat generated by the electric heating element diffuses to the outside of the inner housing, it will be cooled and driven by the flowing air in the air inlet channel and flow into the air outlet channel of the inner housing again, greatly reducing the temperature of the housing. The operator can directly hold the front end of the pen body housing to perform operations, improving the operation fineness, reducing the operation difficulty, and being safe and efficient to use.

[0025] The present invention will be further described below with reference to the accompanying drawings. Description of the Drawings

[0026] Figure 1 It is a three-dimensional structural schematic diagram of Embodiment 1 of the present invention;

[0027] Figure 2 It is a cross-sectional structural schematic diagram of Embodiment 1 of the present invention;

[0028] Figure 3Schematic diagram of the connection structure between the heat insulation sleeve and the outer shell in the first embodiment of the present invention;

[0029] Figure 4 Schematic three - dimensional structure diagram of the second embodiment of the present invention;

[0030] Figure 5 Schematic cross - sectional structure diagram of the second embodiment of the present invention;

[0031] Figure 6 Schematic exploded structure diagram of the inner shell of the present invention;

[0032] Figure 7 Schematic diagram of the connection structure between the fan housing, the fan and the circuit board of the present invention;

[0033] Figure 8 Schematic exploded structure diagram of the outer shell of the present invention;

[0034] Figure 9 Schematic diagram of the hot air flow at the air outlet of the present invention;

[0035] Figure 10 Schematic diagram of the air flow between the air inlet channel and the air outlet channel of the present invention.

[0036] Reference numerals:

[0037] Outer shell 1;

[0038] Concave position 10, first housing 11, annular part 111, cavity part 112, end - cover part 113, docking convex edge 114, buckle position 115, second housing 12, buckle foot 121, screw hole column 13, rib plate 14, convex column 15, half - housing 16;

[0039] Air inlet 101, air inlet channel 102;

[0040] Inner shell 2;

[0041] Electric heating element housing 21, air duct housing 22, fan housing 23, motor seat 231, fan blade sleeve 232, screw hole seat 24, mounting plate 25, rib 26, screw hole 27, connecting column 28;

[0042] Air outlet 201, air outlet channel 202;

[0043] Air suction port 203;

[0044] Fan 3;

[0045] Fan blade 31, motor 32;

[0046] Electric heating element 4;

[0047] Electric heating wire 41, ceramic tube 42, wire 43;

[0048] Circuit board 5;

[0049] Electrical connection structure 51;

[0050] Heat insulation sleeve 6;

[0051] Through hole 61;

[0052] Push-button switch 7;

[0053] PCB board 71;

[0054] Circuit board 8;

[0055] Conductive elastic piece 9. Specific embodiments

[0056] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings, in which 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 by referring to the drawings are exemplary and are only used to explain the present invention and should not be construed as a limitation of the present invention.

[0057] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention. In addition, the features defined as "first" and "second" may explicitly or implicitly include one or more of such features, used to distinguish and describe features, without order or weight.

[0058] In the description of the present invention, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0059] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "cooperate", "be connected", "connect", "install" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0060] The hot air pen with heat recovery involved in the present invention mainly includes a housing 1, an inner housing 2, a fan 3 and a heating element 4. The front end face of the housing 1 is open, and the other faces are sealed. The shape is diverse, such as a cylindrical tube with a circular cross-section in the shape of a circular ring, a tube with a circular outer contour and a polygonal inner contour in the cross-section, a tube with a polygonal outer contour and a circular inner contour in the cross-section, etc. The front and rear end faces of the inner housing 2 are both open, and the other faces are sealed, and there are also various shapes. The fan 3 is arranged in the inner housing 2 and close to the rear end face. The air suction end of the fan 3 faces the rear end opening of the inner housing 2, and the air outlet end faces the front end opening of the inner housing 2. The fans 3 applied to hot air pens or hot air guns mainly include axial fans and centrifugal fans, which can be selected or designed according to requirements. The heating element 4 is arranged in the inner housing 2 and close to the front end face, and can be one or a combination of a metal heating wire 41, a ceramic heating element, a carbon fiber heating core, etc.

[0061] The inner diameter of the housing 1 is larger than the outer diameter of the inner housing 2. For example, Figure 2 or Figure 5 As shown, an air inlet channel 102 is formed between the housing 1 and the inner housing 2, and the front end opening of the housing 1 is the air inlet 101; an air channel 202 is formed inside the inner housing 2, the front end opening of the inner housing 2 is the air outlet 201, and the rear end opening of the inner housing 2 is the air suction port 203. This design with the air inlet 101 and the air outlet 201 on the same side enables the hot air that diffuses after the hot air blows to the welding point for heating to be sucked in by the fan 3 from the air inlet 101, realizing heat recovery, improving the utilization rate of waste heat, reducing the impact of hot air on the working environment, and at the same time avoiding damage to the components around the welding point due to heat. Therefore, compared with existing products, the present invention is more suitable for high-density and high-precision circuit board welding. In addition, the air inlet channel 102 is arranged on the outer ring, and the air outlet channel 202 is arranged inside. After the heat generated by the heating element 4 diffuses to the outside of the inner housing 2, it will be cooled and driven by the air in the air inlet channel 102 and flow into the air outlet channel 202 of the inner housing 2 again, reducing the temperature of the housing 1. The operator can directly hold the front end of the pen body housing 1 for operation, improving the operation fineness, reducing the operation difficulty, and being safe and efficient in use.

[0062] There are various situations for the relative height of the air outlet 201 and the air inlet 101. When they are flush or the air inlet 101 protrudes forward from the edge of the air outlet 201, it may affect the hot processing operation. In order to avoid the hot air blown out from the air outlet 201 being immediately sucked in by the air inlet 101, preferably, the air outlet 201 protrudes forward from the edge of the air inlet 101, such as Figure 2 or Figure 5As shown, the air outlet 201 is closer to the circuit board soldering point, and the hot air blown out can better melt the soldering point. The diffused hot air can also be sucked in by the air inlet 101 from the periphery of the air outlet 201 to achieve heat recovery and improve the utilization rate of waste heat. It can also play a preheating effect to quickly reach the set temperature of the hot air at the air outlet 201; at the same time, it can avoid damage to the components around the soldering point, and the operator can be closer to the circuit board for operation, further improving the operation accuracy.

[0063] In addition to the fan 3 and the heating element 4, the hot air pen also includes a control circuit part. The control circuit is used to control the power of the heating element 4 and the rotation speed of the fan 3, etc. The circuit board 5 serves as the carrier of the control circuit and can be arranged in the outer shell 1 or the inner shell 2. To avoid the influence of high temperature on the performance of the control circuit, it is preferably to arrange the circuit board 5 in the middle or rear part of the outer shell 1 or the inner shell 2. Further, to ensure that the circuit board 5 does not affect the air flow performance and is convenient for wire connection, in some embodiments, such as Figure 2 or Figure 5 As shown, the circuit board 5 and the electrical connection structure 51 are arranged inside the rear end of the outer shell 1, and there is a gap between the rear end face of the inner shell 2 and the bottom of the circuit board 5. This gap can prevent the air suction port 203 from being blocked, and the air in the air inlet channel 102 can enter the air suction port 203 from the gap. The cold air coming in from the air inlet channel 102 can also cool down the circuit board 5. The electrical connection structure 51 is a socket for wire connection, such as a Type-C interface, a USB interface, a DC interface, etc.

[0064] The fan 3, the heating element 4, etc. are installed in the inner shell 2. To ensure the smoothness of the air outlet channel 202 inside the inner shell 2, these electrical components are preferably installed in the middle position of the inner shell 2, and the air outlet channel 202 is located between the inner shell 2 and the electrical components. The inner shell 2 of the present invention can be composed of two half shells on the left and right, and these electrical components are connected to it through the connecting columns 28 extending from both sides inside one of the half shells of the inner shell 2, such as Figure 6As shown in the figure, a preferred structure of the inner shell 2 includes, in sequence from the front end to the rear end, an electric heating element housing 21, an air duct housing 22, and a fan housing 23. All three housings can be cylindrical, and adjacent housings are connected by plugging, or other methods such as screw threading or rotational snap connection can also be used. The electric heating element 4 is installed in the electric heating element housing 21, and the fan 3 is installed in the fan housing 23. The installation method is to set an installation plate 25 in the middle of the housing, with a gap formed between the outer contour of the installation plate 25 and the inner wall of the housing. The installation plate 25 is fixed in the middle of the housing by connecting narrow ribs 26 to the inner wall of the housing. The electric heating element 4 or the fan 3 is installed on the installation plate 25. The sizes of the electric heating element 4 and the fan 3 should be smaller than the inner cavity of the corresponding installation housing to ensure that the air outlet channel 202 in the inner shell 2 is not blocked. The air duct housing 22 is designed as a wind collecting duct that is narrow at the front and wide at the rear. When cold air passes through, the cross-sectional area gradually decreases and the flow rate gradually increases, enabling better entry into the electric heating element housing 21 for heating to meet the air outlet requirements. In some embodiments, a circuit board 8 is provided in the air duct housing 22 and fixed at the middle position of the air duct housing 22. The electric heating element 4 is installed on this circuit board 8 through wires. With this installation method, the electric heating element 4 does not need to be connected to the electric heating element housing 21 and is suspended in the middle of the electric heating element housing 21 through wires. The motor 32 is also electrically connected to this circuit board 8.

[0065] The structure of the outer shell 1 is diverse, such as being composed of symmetric left and right half shells, or being connected by a front half pen shell and a rear half pen shell like a writing pen, etc. As Figure 8 shown in the example, the outer shell 1 includes a first shell 11 and a second shell 12. The first shell 11 includes an annular part 111 at the front end, a semi-cylindrical cavity part 112 in the middle, and an end cover part 113 at the rear end. The inner shell 2 is placed into the outer shell 1 from the cavity part 112 and fixed by screws; the second shell 12 can be covered on the open end of the cavity part 112 to form a semi-cylindrical shell with an overall cylindrical shape together with the cavity part 112. The second shell 12 is hermetically connected to the first shell 11, and the connection can be snap connection or clamping. To improve the sealing performance, a sealing rubber edge or rubber ring can be provided at the connection.

[0066] Specific descriptions will be given for specific embodiments below.

[0067] Embodiment 1:

[0068] As Figures 1 to 3 shown, the heat-recoverable hot air pen of this embodiment includes an outer shell 1, a heat insulation sleeve 6, an inner shell 2, a fan 3, and an electric heating element 4.

[0069] Outer shell 1: The outer shape is similar to a cylindrical pen shell. The outer diameter of the front half is smaller than that of the rear half, and a concave position 10 for the operator to hold the hot air pen is provided in the front half; the front end face of the outer shell 1 is provided with an opening, while the rear end face and the arc surface are both sealed. The outer shell 1 of this embodiment includes a first shell 11 and a second shell 12, as Figure 8As shown, the first shell 11 includes a front annular portion 111, a semi-cylindrical cavity portion 112 in the middle, and an end cover portion 113 at the rear end. The heat insulating sleeve 6 and the inner shell 2 can be placed into the first shell 11 from the cavity portion 112; and the second shell 12 is designed to cover the open end of the cavity portion 112 to form a semi-cylindrical shell with the cavity portion 112 as a whole. The first shell 11 is provided with a docking flange 114 at the edge of the cavity portion 112, and two buckle positions 115 are provided on the docking flange 114; a buckle foot 121 is provided at the edge of the second shell 12, and the buckle foot 121 is buckled with the buckle position 115 to realize the sealed connection between the first shell 11 and the second shell 12. This buckling method is convenient for assembly and disassembly, and can ensure the sealing of the shell and reduce heat loss.

[0070] Inner shell 2: The outer shape is similar to that of outer shell 1, but the diameter of the rear half is large and the diameter of the front half is small. The overall outer diameter is smaller than the inner diameter of outer shell 1, and a gap is formed between inner shell 2 and outer shell 1. The front and rear faces of inner shell 2 both have openings, and the arc surface is sealed. The front opening is the air outlet 201, and the rear opening is the air intake 203. Figure 6 As shown, from the front end to the rear end, the electric heating element housing 21, the air duct housing 22 and the fan housing 23 are respectively included, and the fan housing 23 is further divided into a motor seat 231 and a fan blade cover 232. The electric heating element housing 21 is connected to the air duct housing 22, the air duct housing 22 is connected to the front end of the motor seat 231, and the rear end of the motor seat 231 is connected to the fan blade cover 232. The connection mode is realized by plugging, and the air duct housing 22 and the motor seat 231, the motor seat 231 and the fan blade cover 232 are also added with a snap-on buckle connection on the basis of plugging, so as to enhance the connection firmness and avoid the plug-in separation caused by the working vibration of the fan 3. The air duct housing 22 is a wind collecting air duct that is narrow in front and wide in the back. The air blown in by the fan 3 gradually increases its flow rate in it, and can better enter the electric heating element housing 21 for heating and meet the air outlet demand. The inner shell 2 is connected to the outer shell 1 by screws, and screw holes 24 are provided on both sides of the outer shell 22, and screw holes 13 are provided on both sides of the inner shell 11 of the outer shell 1. After the screw holes 24 are aligned with the screw holes 13, they are screwed together to fix the inner shell 2 on the first shell 11.

[0071] Fan 3: It is arranged in the inner shell 2 and close to the rear end surface. Figure 7As shown in the figure, the fan 3 includes a fan blade 31 and a motor 32. The motor 32 is installed at the middle position of the motor base 231. The specific installation method is that an installation plate 25 is arranged in the middle of the rear part of the motor base 231. There is a gap between the outer contour of the installation plate 25 and the inner wall of the motor base 231. The installation plate 25 is connected to the inner wall of the motor base 231 through 2 - 4 narrow ribs 26, and the installation plate 25 is fixed in the middle of the motor base 231. The installation plate 25 is provided with screw holes 27, and the motor 32 is fixed by screwing into the screw holes 27. The outer diameter of the motor 32 is similar to the outer diameter of the installation plate 25, and an air duct is formed between the motor 32 and the inner wall of the motor base 231. The fan blade 31 is installed in the fan blade sleeve 232, behind the motor 32. The rotating shaft of the motor 32 extends backward into the fan blade sleeve 232 to be connected with the fan blade 31 to drive it to rotate. The air suction end of the fan blade 31 faces the opening at the rear end of the inner shell 2, and the opening at the rear end of the inner shell 2 forms an air suction port 203. The air outlet end of the fan blade 31 faces the opening at the front end of the inner shell 2, that is, towards the direction where the motor 32 is located. This design enables the fan 3 to effectively suck air from the air suction port 203 and blow it towards the heating element 4 for heating.

[0072] Heating element 4: It is arranged in the inner shell 2 and close to the front end face. As Figure 2 shown in the figure, the heating element 4 is installed in the heating element housing 21. The heating element housing 21 is a cylindrical body. Its rear end is inserted into the front end of the air duct housing 22, and the front opening extends forward beyond the edge of the front opening of the outer shell 1. This front opening is the air outlet 201. The heating element 4 includes a heating wire 41 wound in a spiral shape and a hollow ceramic tube 42 located in the middle of the heating wire 41. Gaps are formed between the heating wire 41 and the inner wall of the heating element housing 21, and between the heating wire 41 and the ceramic tube 42. The cold air conveyed in the air duct housing 22 can be quickly heated to form hot air in these gaps. A circuit board 8 is arranged at the middle position in the air duct housing 22. The heating element 4 is connected to the circuit board 8 through a wire 43, suspending the heating wire 41 and the ceramic tube 42 in the middle of the heating element housing 21. One end of each of the two wires 43 is respectively connected to both ends of the heating wire 41, and the other ends are both connected to the circuit board 8. The motor 32 is also electrically connected to this circuit board 8. This suspended installation method enables the cold air to fully contact the heating wire 41, improving the heating efficiency, and at the same time facilitating the replacement and maintenance of the heating element 4.

[0073] Heat insulation sleeve 6: It is arranged inside the front half of the outer shell 1, with openings at both the front end face and the rear end face. Its overall length is approximately one-third of the length of the outer shell 1 and is basically the same as the length of the electric heating element housing 21. The front opening also extends beyond the edge of the front opening of the outer shell 1 and is connected in a fitting manner with the inner wall of the outer shell 1. The inner diameter of the heat insulation sleeve 6 is larger than the outer diameter of the inner shell 2, and there is a gap between the heat insulation sleeve 6 and the inner shell 2. The front half of the air inlet channel 102 is located in the gap between the heat insulation sleeve 6 and the inner shell 2, and the rear half is the gap between the outer shell 1 and the inner shell 2; the air inlet 101 is located at the front opening of the heat insulation sleeve 6. The heat insulation sleeve 6 can isolate the waste heat recovery and the hot air diffused from the inner shell 2 into the air inlet channel 102, preventing it from being rapidly and massively transferred to the outer shell 1 and reducing the temperature of the outer shell 1. The connection method between the heat insulation sleeve 6 and the outer shell 1 can be the same as the connection method between the inner shell 2 and the outer shell 1, that is, locked by screws, or the outer wall of the heat insulation sleeve 6 can be directly and completely fitted and installed with the inner wall of the outer shell 1. However, in order to simplify the connection and reduce the contact area between the heat insulation sleeve 6 and the outer shell 1 to reduce heat conduction, as Figure 3 shown in the embodiment, there is a gap between the heat insulation sleeve 6 and the outer shell 1. The inner wall of the outer shell 1 is provided with a plurality of rib plates 14 extending into the gap to be connected with the outer wall of the heat insulation sleeve 6, positioning the heat insulation sleeve 6 at the coaxial position with the outer shell 1. The contact area between the rib plates 14 and the heat insulation sleeve 6 is small, with less heat conduction, and there are gaps between the rib plates 14, forming a similar heat dissipation fin pattern, which can quickly dissipate the conducted heat energy and prevent it from being transferred to the outer shell 1. In addition, a convex column 15 protrudes from the inner wall of the outer shell 1, and a through hole 61 is opened on the heat insulation sleeve 6. The heat insulation sleeve 6 and the outer shell 1 are axially positioned by the cooperation of the convex column 15 and the through hole 61, preventing the heat insulation sleeve 6 from falling forward from the front opening of the outer shell 1.

[0074] As Figure 2 shown, the air outlet 201 of this embodiment protrudes more forward from the edge of the front opening of the outer shell 1 than the air inlet 101, that is, the front opening of the electric heating element housing 21 extends further forward than the front opening of the heat insulation sleeve 6, so that the air outlet 201 can be closer to the circuit board 5, which is more conducive to the welding operation. From Figure 2 it can be seen that the front half of the air inlet channel 102 of this hot air pen is the gap between the heat insulation sleeve 6 and the inner shell 2, and the rear half is the gap between the outer shell 1 and the inner shell 2; while the air outlet channel 202 is the air duct formed by the inner cavity of the inner shell 2.

[0075] Control circuit part: It includes a circuit board 5 and an electrical connection structure 51. The electrical connection structure 51 is installed on the circuit board 5, and the circuit board 5 is arranged inside the rear end of the outer shell 1. On the outer wall of the rear end face of the fan blade sleeve 232 of the inner shell 2, two connecting posts 28 extend backward. Threaded holes are provided on the connecting posts 28, and correspondingly two through holes 61 are provided on the circuit board 5. After aligning the through holes 61 with the connecting posts 28, screws are passed through the through holes 61 and screwed into the threaded holes to realize the connection and fixation of the circuit board 5 and the connecting posts 28, and at the same time form a gap between the circuit board 5 and the air suction port 203. The electrical connection structure 51 in this embodiment is a Type-C interface, and a strip-shaped through hole with the same shape as the Type-C interface is correspondingly provided on the rear end face of the outer shell 1 for the Type-C interface to extend out. In addition, a key switch 7 is provided on the outer shell 1. The inner side of the key switch 7 is connected with a PCB board 71. The PCB board 71 is fixed on the outer wall of the air duct housing 22 and is electrically connected to the circuit board 8. Conductive elastic pieces 9 are provided on the PCB board 71 and extend to the rear end of the outer shell 1 to be electrically connected to the circuit board 5. By pressing the key switch 7, the start and stop of the hot air pen, the adjustment of the temperature of the heating element 4, the adjustment of the rotation speed of the fan 3, etc. can be realized.

[0076] Working principle: The operator holds the concave position 10 at the front half of the outer shell 1 of the hot air pen and presses the key switch 7 to start the motor 32 and the heating element 4. The motor 32 drives the fan blade 31 to rotate, and the heating element 4 starts to heat. Under the suction force generated by the rotation of the fan blade 31, the outside air enters from the air inlet 101 of the heat insulation sleeve 6, moves along the air inlet channel 102 towards the rear end of the outer shell 1, and is sucked into the inner shell 2 by the fan blade 31 near the air suction port 203, and then enters the air duct housing 22 under the drive of the fan blade 31. After the air flow rate increases in the air duct housing 22, it enters the heating element housing 21, is heated by the heating element 4 and then blows out from the air outlet 201 to become hot air. The temperature of the initially blown hot air does not meet the operation requirements. When it diffuses, it will be sucked into the air inlet 101 again, and the heat dissipated by the inner shell 2 will also be sucked into the inner shell 2 and reheated and then blown out from the air outlet 201. In this way, the inhaled air is mixed with the hot air, the heating speed is accelerated, and the blown hot air quickly reaches the operation temperature. This design with the air inlet 101 and the air outlet 201 on the same side realizes heat recovery, achieves a preheating effect, reduces the preheating time, improves the waste heat utilization rate, reduces the impact of the hot air on the working environment, and avoids the components around the welding point from being damaged by heat. At the same time, the heat insulation sleeve 6 further insulates the outer shell 1, ensuring that the operator will not feel overheated when holding the outer shell 1, and can operate in a pen-holding style, with simpler operation and higher precision. Moreover, the cold air flowing in the air inlet channel 102 can continuously take away the heat transferred from the inner wall of the outer shell 1 and the outer wall of the inner shell 2, further reducing the temperature of the outer shell 1 and improving the safety and comfort of use.

[0077] Embodiment 2:

[0078] As Figure 4and Figure 5 As shown, the heat-recoverable hot air pen of this embodiment includes a housing 1, an inner housing 2, a fan 3, and a heating element 4.

[0079] Housing 1: Its outer shape is the same as that of the housing 1 in the first embodiment. The front end is open to serve as the air inlet 101 of the hot air pen. It is composed of two left and right half shells 16 butt-jointed. The butt-joint edge uses a buckle 121 to cooperate with a buckle position 115 for buckling. This butt-joint buckling method facilitates the assembly and disassembly of the housing 1 and can also ensure a certain degree of airtightness.

[0080] Inner housing 2: Its outer shape is the same as that of the inner housing 2 in the first embodiment. It is composed of two left and right half shells butt-jointed. The fan 3 and the heating element 4 are installed in the middle position of the inner housing 2. There are gaps between the fan 3 and the inner wall of the inner housing 2, and between the heating element 4 and the inner wall of the inner housing 2 to form an air duct. The inner housing 2 is also connected to the housing 1 by screws. This design enables air to flow smoothly inside the inner housing 2 and ensures the normal output of hot air.

[0081] Other components: The specific structures of the fan 3, the heating element 4, the circuit board 5, the electrical connection structure 51, and the key switch 7 are the same as those in the first embodiment.

[0082] This embodiment does not provide a heat insulation sleeve 6. The entire air inlet channel 102 is formed by the gap between the housing 1 and the inner housing 2, and the air outlet channel 202 is the inner cavity of the inner housing 2. The front end opening of the inner cavity protrudes forward beyond the front end opening edge of the housing 1, that is, the air outlet 201 is closer to the circuit board 5 being operated than the air inlet 101.

[0083] Working principle: The operator holds the concave position 10 at the front half of the hot air pen housing 1, presses the button switch 7 to start the motor 32 and the heating element 4. The motor 32 drives the fan blade 31 to rotate, and the heating element 4 starts to heat up. Under the suction force generated by the rotation of the fan blade 31, the outside air enters from the air inlet 101 of the housing 1, moves along the air inlet passage 102 towards the rear end of the housing 1, and is sucked into the inner housing 2 by the fan blade 31 near the air suction port 203. Then, it enters the position where the heating element 4 is located under the drive of the fan blade 31, is heated by the heating element 4, and is blown out from the air outlet 201 as hot air. The temperature of the initially blown hot air does not meet the operation requirements. When it diffuses, it will be sucked in again by the air inlet 101. The heat dissipated by the inner housing 2 will also be sucked into the inner housing 2, reheated, and then blown out from the air outlet 201. In this way, the inhaled air is mixed with the hot air, accelerating the heating speed, enabling the blown hot air to quickly reach the operation temperature. The same-side design of the air inlet 101 and the air outlet 201 realizes heat recovery, achieves a preheating effect, reduces the preheating time, improves the waste heat utilization rate, reduces the impact of hot air on the working environment, and avoids heat damage to the components around the welding point. Although there is no heat insulation sleeve 6 for further heat insulation, the air in the air inlet passage 102 between the housing 1 and the inner housing 2 flows rapidly, which can drive the hot air dissipated by the inner housing 2 to move towards the rear end of the housing 1 and re-enter the inner housing 2. Therefore, holding the housing 1 will not cause burns, and the pen-holding style operation can still be adopted, with simpler operation and higher precision. Due to the absence of the heat insulation sleeve 6, the structure of this embodiment is relatively more concise, reducing the number of components and lowering the production and maintenance costs.

[0084] Comparison of Embodiments and Applicable Scenarios

[0085] 1. Embodiment 1: A heat insulation sleeve 6 is provided, which can further reduce the temperature of the housing 1. During long-term continuous use, it can effectively avoid the risk of the housing 1 overheating and causing discomfort or even burns to the operator. Therefore, it is suitable for scenarios with long-term continuous use or high requirements for operation safety, such as large-scale circuit board welding operations. In such operations, the operator needs to hold the hot air pen for a long time for fine operations. The lower housing temperature can ensure the comfort and stability of the operation, reducing operation errors caused by discomfort due to hand heating.

[0086] 2. Embodiment 2: The heat insulation sleeve 6 is not provided, but the air flow in the air inlet passage 102 can also effectively reduce the temperature of the housing 1. Its structure is relatively simple, reducing the use of the heat insulation sleeve 6 and its related connection structures, and lowering the production cost. It is applicable to welding operation scenarios that are sensitive to cost and have a relatively short usage time, such as the daily repair work in small electronic repair shops. Under the premise of meeting the basic heat recovery and operation requirements, it can effectively control costs.

[0087] In the description of this specification, the descriptions referring to terms such as "embodiment", "example", etc. mean that the specific features, structures, materials or characteristics described in connection with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples.

[0088] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A heat-recoverable hot air pen, characterized in that: include: The housing is constructed as a shell having an opening on the front end surface and sealed on the other surfaces; An inner shell, which is constructed as a shell with openings on both the front and rear faces and sealed on the other faces; A fan is arranged in the inner shell and close to the rear end surface, the air suction end of the fan is opened toward the rear end of the inner shell, and the air outlet end of the fan is opened toward the front end of the inner shell, and the fan is used to provide power for air flow; An electric heating element, disposed in the inner shell and close to the front end surface, for heating air; The inner diameter of the outer shell is larger than the outer diameter of the inner shell, so that an air inlet channel is constructed between the outer shell and the inner shell, and the front end opening of the outer shell is constructed as an air inlet; the interior of the inner shell is constructed as an air outlet channel, the front end opening of the inner shell is constructed as an air outlet, and the rear end opening of the inner shell is constructed as an air intake.

2. The heat-recoverable hot air pencil according to claim 1, characterized in that: The air outlet protrudes forward from the edge of the air inlet.

3. The heat-recoverable hot air pencil according to claim 1, characterized in that: A circuit board and an electrical connection structure are arranged inside the rear end of the outer shell, and a gap is arranged between the rear end surface of the inner shell and the bottom of the circuit board.

4. The heat-recoverable hot air pencil according to claim 1, characterized in that: It also includes a heat-insulating sleeve with openings on both the front and rear faces, the heat-insulating sleeve is arranged inside the outer shell and close to the air inlet, the heat-insulating sleeve is cooperatively connected to the inner wall of the outer shell, the inner diameter of the heat-insulating sleeve is larger than the outer diameter of the inner shell, so that the air inlet channel is configured to be located between the heat-insulating sleeve and the inner shell, and the air inlet is configured to be located at the front end opening of the heat-insulating sleeve.

5. The heat-recoverable hot air pen according to claim 4, characterized in that: A gap is arranged between the heat-insulating sleeve and the outer shell, and a plurality of ribs extending into the gap are arranged on the inner wall of the outer shell to be matched and connected with the outer wall of the heat-insulating sleeve.

6. The heat-recoverable hot air pencil according to claim 1, characterized in that: The inner shell includes an electric heating element shell, an air duct shell and a fan shell from the front end to the rear end, the electric heating element is installed in the electric heating element shell, the air duct shell is a wind collecting duct that is narrow in the front and wide in the back, the fan is installed in the fan shell, and the electric heating element shell and the air duct shell, as well as the air duct shell and the fan shell are connected by plugging.

7. The heat-recoverable hot air pencil according to claim 6, characterized in that: The fan housing includes a motor base and a fan blade cover. The front end of the motor base is plugged into the air duct housing, the rear end of the motor base is sleeved with the fan blade cover, and the air suction port is arranged on the rear end surface of the fan blade cover.

8. The heat-recoverable hot air pencil according to claim 7, characterized in that: The fan comprises fan blades and a motor. The motor is installed in the motor base. The motor is located in the middle of the motor base. An air duct is formed between the motor and the inner wall of the motor base. The fan blades are installed in the fan blade sleeves.

9. The heat-recoverable hot air pencil according to claim 7, characterized in that: A connecting column is extended backward from the outer wall of the rear end surface of the fan cover, and a circuit board is arranged inside the rear end of the shell. The circuit board is connected and fixed to the connecting column to form a gap between the circuit board and the air suction port.

10. The heat-recoverable hot air pencil according to claim 1, characterized in that: The outer shell includes a first shell and a second shell, the first shell includes an annular portion at the front end, a semi-cylindrical cavity portion in the middle, and an end cover portion at the rear end, the inner shell is inserted into the outer shell from the cavity portion and fixed by screws; the second shell is designed to cover the open end of the cavity portion to form an overall cylindrical semi-cylindrical shell with the cavity portion, and the connection between the second shell and the first shell is a sealed connection.

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