Preheating device and preheating method for workpiece

Abstract

The present invention relates to a preheating device and a preheating method for a workpiece. Specifically, the preheating device comprises: a base (20); a heating unit (30), which is composed of heating bodies (31) arranged on the base (20), wherein the heating bodies (31) form a heating body array, wherein the heating bodies (31) can work individually to form a desired preheating profile. Through the preheating device, after the heating bodies of the heating unit are selected, the area to be preheated of the workpiece can be accurately matched to achieve efficient preheating, and the flexibility of the preheating device is improved.

Description

Technical Field

[0001] The invention relates to a preheating device and a preheating method for a workpiece. Background Art

[0002] Due to its low technical cost, high assembly efficiency and good bonding strength, welding technology is widely used in the field of plastic parts assembly.

[0003] For example, friction welding is a well-known welding technique, offering fast cycle times and requiring no independent heat source. However, a significant drawback of friction welding in industrial production is the generation of weld impurities, known as slag, during the welding process. This can lead to weld failure rates as high as 5%. Furthermore, friction welding imposes stringent requirements on product design. If a product's key structural design fails to meet these requirements, the defect rate due to weld impurities will further increase.

[0004] To solve the problem of welding impurities, a preheating process is usually used before welding, that is, the part of the plastic part to be welded is preheated to skip the primary stage of friction welding heating, thereby reducing the brittle damage of the material and achieving the purpose of clean welding.

[0005] For example, document US2016107372 discloses a plastic preheating structure for a plastic welding device, which includes a bracket, at least one first preheating device, and a pivot mechanism, through which the at least one first preheating device can be pivoted to a preheating position relative to the first surface of the bracket, so that the bite edge of a first component can be bypassed and the first component can be heated by the first preheating device.

[0006] However, in the plastic preheating structure known from US2016107372, the preheating process is integrated into the welding equipment and fixture, which is not conducive to the efficiency of friction welding. In addition, this plastic preheating structure has a high cost investment. Summary of the Invention

[0007] Therefore, the object of the present invention is to provide a preheating device which can be flexibly and cost-effectively adapted to the region of a workpiece to be preheated so as to achieve uniform preheating.

[0008] Another object of the present invention is to provide a method for preheating a workpiece.

[0009] This objective is achieved by a preheating device comprising a base and a heating unit. The heating unit comprises heating elements arranged on the base, forming a heating element array. The heating elements can operate individually to create a desired preheating profile. This enables efficient preheating by selecting the appropriate heating element to match the area to be preheated, eliminating the need to design a separate preheating device for each workpiece, thereby increasing the flexibility of the preheating device.

[0010] The preheating device may further include a shield, which is arranged above the heating unit and has a predetermined opening whose shape matches the desired preheating profile, so that heat radiation from the uncovered heated body can be transmitted outward through the opening. This enables the heat radiation emitted by the heating body of the heating unit to be directed in a direction.

[0011] Preferably, the shade comprises an inner section and an outer section arranged on either side of the opening, and a bridge portion connecting the inner section and the outer section. Such a shade can be punched in one piece, or the parts can be prefabricated from suitable materials and then connected to form the shade, such as by welding or other suitable means.

[0012] In the use state, the bridge portion of the shade is arranged directly above the heating element, so that the heat radiation emitted by the heating element can be reflected by the bridge portion towards both sides thereof, thereby achieving uniform preheating.

[0013] In use, the bridging portion of the shade can be positioned between two adjacent heating elements, with the height of the bridging portion being lower than the plane where the highest points of the two heating elements are located. In other words, the bridging portion is positioned between the housings of the heating elements, lowered relative to the sections on either side of it. This maximizes the unimpeded passage of heat radiation from the heating elements through the opening, thereby achieving efficient utilization of the heat radiation.

[0014] The height of the heating body can be adjusted. To this end, the heating body may have a spring mechanism so that the height can be adjusted by deformation of the spring mechanism. In this case, a shield with an opening that matches the contour of the workpiece can be covered on the heating unit, and then the shield is pressed down. When the corresponding heating body is adjusted to be below the opening of the shield, the shield is fixed, and preheating of the part of the workpiece that needs to be preheated can be started. Alternatively, the heating body has a spiral mechanism so that the height can be adjusted by rotating the spiral mechanism. After selecting the corresponding heating body, by adjusting the height of the heating body to a suitable position, the relevant parts of the workpiece can be preheated in conjunction with the shield if necessary. This can further enhance the flexibility of the preheating device. Other solutions that can achieve height adjustment of the heating body are also feasible.

[0015] The preheating device may also be provided with a heat radiation reflection mechanism. The heat radiation reflection mechanism may be a heat radiation reflection layer or a first heat radiation reflection cover provided on the heating element. The heat radiation reflection mechanism may also be a second heat radiation reflection cover provided at the opening of the shade. By providing the heat radiation reflection mechanism, heat radiation emitted by the heating element is reflected toward the opening, further improving the utilization rate of heat radiation, thereby shortening the time required to preheat the workpiece.

[0016] The preheating device also has a control device, which can select and activate the heating body to be operated.

[0017] By using the preheating device according to the present invention, after selecting the heating body of the heating unit, and in cooperation with the shield when necessary, the area to be preheated of the heated workpiece can be accurately matched to achieve efficient preheating, and the flexibility of the preheating device is improved.

[0018] A method for preheating a workpiece in the above-mentioned preheating device is also proposed, comprising the following steps: selecting a corresponding heating body from an array of heating bodies formed by single heating bodies in a heating unit of the preheating device according to the contour of the workpiece to be preheated; adjusting the height of the heating body to match the height of the contour of the workpiece to be preheated; placing the workpiece to be preheated above the selected heating body; and triggering the selected heating body to work so as to preheat the contour of the workpiece to be preheated.

[0019] In this method, the height of the heating body is adjusted by covering the heating unit with a mask having an opening matching the contour of the workpiece to be preheated and pressing the heating body downward to deform the spring mechanism of the heating body.

[0020] Alternatively, the height of the heating body is adjusted by rotating the screw mechanism.

[0021] Preferably, the operation of the heating element is triggered by a control device. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be further described below with reference to the accompanying drawings, wherein:

[0023] Figure 1 A schematic diagram showing the working principle of the preheating device according to the present invention;

[0024] Figure 2 shows a schematic cross-sectional view of a preheating device according to the present invention;

[0025] Figure 3 A schematic diagram showing the outline of the area to be preheated formed by using a mask having a first opening, wherein the mask is not shown;

[0026] Figure 4A schematic diagram showing the outline of the area to be preheated formed by using a shade having a second opening, wherein the shade is not shown;

[0027] Figure 5 Shows the corresponding Figure 4 A schematic illustration of a mask with an outline of the area to be preheated;

[0028] Figure 6 shows a schematic diagram of a light emitting unit;

[0029] Figure 7 A schematic diagram of a mask is shown;

[0030] Figure 8 shows another schematic representation of a light emitting unit; and

[0031] Figure 9 Another schematic illustration of a lighting unit is shown. DETAILED DESCRIPTION

[0032] The following describes embodiments of the present invention by way of example. As will be appreciated by those skilled in the art, the embodiments described may be modified in various ways without departing from the spirit of the present invention. Therefore, the drawings and description are illustrative and non-restrictive in nature. Hereinafter, the same reference numerals generally indicate elements with the same or similar functions.

[0033] The preheating device 1 according to the present invention comprises a base 20 and a heating unit 30. The heating unit 30 is formed by heating bodies 31 arranged on the base 20, wherein the heating bodies 31 form a heating body array. The heating bodies 31 can work individually to form a desired preheating profile.

[0034] Figure 1 The figure shows a schematic diagram of the working principle of the preheating device 1 according to the present invention. Here, the heating body 31 to be operated can be selected from the heating body array according to the contour of the workpiece to be preheated. When the power is turned on, the selected heating body 31 can form the desired preheating contour, and the formed preheating contour matches the contour of the part 11 to be preheated of the workpiece 10. Figure 1 Two different preheating profiles are shown in FIG. 3 which are formed by the selected heating body 31. It should be mentioned that the preheating profile is not limited to Figure 1 The linear preheating profile shown in FIG. 1 may also be a point preheating profile or a surface preheating profile.

[0035] In the preheating device 1, a shield 40 may be further arranged above the heating unit 30. The shield 40 at least partially covers the heating element 31 and has an opening 404. A workpiece 10 is placed on the shield 40, with the portion 11 of the workpiece 10 to be preheated located above the opening 404, that is, within the range of heat radiation from the heating element 31 below the opening 404. This allows the portion 11 of the workpiece 10 to be preheated to be preheated by the heat radiation from the heating element 31 during operation. The shield 40 and the heating unit 30 will be further described below. Figure 3 and Figure 4 The preheating profiles formed by the selected heating elements 31 after being covered by the mask 40 are schematically shown, wherein the mask 40 has different openings 404 and the unselected heating elements 31 are not visible due to being covered.

[0036] Figure 2 A side view of an embodiment of a preheating device 1 according to the present invention is schematically shown. The preheating device 1 includes a base 20, a heating unit 30 and a shield 40. The workpiece 10 is placed on the shield 40. The shield 40 is provided with an opening 404, which is located above the selected heating body 31, wherein the direction of the opening 404 corresponds to the direction of the portion 11 of the workpiece 10 to be preheated. In addition, the contour of the shield 40 can also be matched with the contour of the workpiece 10. In particular, when the workpiece 10 is a special-shaped part, the shield 40 and its opening 404 are not on the same plane. Correspondingly, the heating body 31 can be arranged along Figure 2 The heating element 31 can be moved in the direction of the double arrow shown in FIG. , that is, the height can be adjusted vertically so that the top surface of the heating element 31 matches the surface contour of the shade. In this case, the height position of the heating element 31 can be actively or passively adjusted when the preheating device 1 is in use.

[0037] Figure 2 1 shows an example of a heating body 31 of a heating unit 30 of a preheating device 1 , the height of which is adjustable. Figure 6 A diagram of such a heating body 31 is shown. Figure 6 As can be seen, the heating body 31 includes a housing 301, a heat radiator 302 disposed in the housing 301, and a guide sleeve 306. Furthermore, the heating body 31 also includes a first baffle 303 fixedly connected to the housing 301, a second baffle 305 fixedly connected to the guide sleeve 306, and a spring 304 disposed between the first baffle 303 and the second baffle 305. The housing 301 of the heating body 31 can move within the guide sleeve 306 under the action of the spring 304 and the guidance of the guide sleeve 306. To this end, the shade 40 may be provided with a structure acting on the first baffle 303, such as in Figure 2The pressure plate 405 is shown in FIG. When the preheating device 1 is in use, the mask 40 equipped with the pressure plate 405 is placed above the heating unit 30. The pressure plate 405 abuts against the first baffle 303 of each heating element 31. The spring 304 of the heating element 31 is compressed to a corresponding degree to match the contour of the pressure plate 405, and the housing 301 moves a corresponding distance in the guide sleeve 306. This ensures that the upper surface of the heating element array matches the contour of the mask, and ultimately matches the contour of the workpiece and the portion of the workpiece to be preheated.

[0038] Apart from Figure 6 In addition to the heating body 31 with a spring shown in FIG, the heating body 31 may also have other embodiments. For example, Figure 9 shows another embodiment of a heating element 31. This heating element 31 also comprises a housing 301, a heat radiator 302 disposed within the housing 301, and a guide sleeve 306. However, the housing 301 and the guide sleeve 306 are screwed together. Therefore, the height of the heating element 31 can be adjusted by screwing the housing 301 into or out of the guide sleeve 306. After the height of each heating element 31 is generally adjusted, a preformed shield having a predetermined opening is placed above the heating unit 30. The workpiece 10 is then placed on the shield to begin the preheating process.

[0039] Of course, in addition to the heating body 31 of the above embodiment, other embodiments of the heating body 31 whose height direction can be adjusted can be considered.

[0040] In order to improve the utilization rate of the heat radiation of the luminous body 30 , a heat radiation reflection mechanism may be provided at the luminous body 30 and / or the shade 40 .

[0041] The heat radiation reflection mechanism can be arranged at the luminous body 30. Figure 8 As shown in FIG, a first heat radiation reflector 307 may be provided at the heating body 31. The first heat radiation reflector 307 may be placed at the first baffle 303. Here, the first heat radiation reflector 307 reflects the heat radiation emitted by the heat radiating body 302 toward the opening in the direction indicated by the arrow, thereby improving the utilization rate of the heat radiation.

[0042] When the housing 301 of the light emitting body 30 is made of a transparent bulb (e.g., a quartz bulb), a reflective layer, such as a gold plating layer, can be applied to the housing, for example, on its surface, and a transparent, transparent portion can be left at the top of the housing. This can also improve the utilization and concentration of thermal radiation.

[0043] In addition, the heat radiation reflection mechanism can also be provided at the shade 40. Figure 7As shown in FIG, the shield 40 is provided with a conical second heat radiation reflector at its opening 404, which can also be used as a pressure plate 405, which radiates the heat of the heating body 31 as shown in FIG. Figure 7 The direction indicated by the middle arrow is reflected toward the opening, thereby improving the utilization rate and concentration of heat radiation.

[0044] Reference below Figure 5 Schematically illustrating a shield 40 for a preheating device 1, wherein a schematic top view of the shield 40 is shown. The shield 40 comprises an outer section 401, an inner section 402, a bridge 403 connecting the outer section 401 and the inner section 402, an opening 404 between the outer section 401, the inner section 402 and the bridge 403, and an optional pressure plate 405. The direction of the opening 404 shown here corresponds to Figure 4 The direction of the selected heating element 31 to be activated is, in other words, the direction of the contour of the portion 11 of the workpiece 10 to be heated. It should be noted that the direction of the opening of the shield can be designed according to the direction of the specific portion of the workpiece to be heated, and the contour shape of the shield needs to match the shape of the workpiece. In other words, the shield is not limited to a flat shape and can also be a curved surface. In particular, for heating units with a spring structure, the shield has a pressure plate to adjust the corresponding heating element of the heating unit to the desired height. The pressure plate can be cylindrical or truncated conical, and it presses against the cover of the heating element connected to the spring or a related component of the cover to achieve the height adjustment of the heating element through the compression of the spring.

[0045] In the use state, the bridge portion 403 of the shade 40 can be arranged directly above the selected heating body 31 , which helps to evenly transmit heat radiation along the direction of the opening.

[0046] Alternatively, in the use state, the bridge portion 403 of the shade 40 may not be located on a continuous surface relative to the inner section 401 and the outer section 402 of the shade. Specifically, the bridge portion 403 is sunken relative to the outer section 401 and the inner section 402 in the use position and is located between the housings 301 of the adjacent heating bodies 31, as shown in FIG. Figure 5 As shown, the heat radiation emitted by the heat radiator 302 is transmitted through the opening 404 without being blocked by the bridge portion 403 , which is conducive to fully utilizing the heat radiation emitted by the heat radiator 302 and quickly and evenly preheating the portion 11 of the workpiece 10 to be preheated.

[0047] It should be noted here that the opening 404 of the shield 40 is not limited to the annular opening shown in the accompanying drawings, but can be configured in other ways as needed. For example, an open-loop linear opening or a planar opening can be configured, and the number of the openings is not limited to one but can be multiple, as long as the direction of the openings matches the corresponding part of the workpiece to be preheated.

[0048] The heating element 31 can be an infrared bulb, which can provide energy radiation that can be accurately controlled. Especially when the bulb is coated with a reflective coating, the angle of the thermal radiation can be controlled. Of course, other forms of heating elements are also feasible.

[0049] The preheating device 1 may further comprise a control device, which can select and trigger the heating body to be operated, for example, disconnecting and connecting the power supply of the heating body.

[0050] The present invention is not limited to the above-described configuration, and various other variations are also possible. Although the present invention has been described with reference to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, may devise other embodiments that do not depart from the scope of the invention disclosed herein. Therefore, the scope of the present invention shall be limited solely by the appended claims.

Claims

1. A preheating device (1), comprising: base (20); A heating unit (30) is composed of a heating body (31) arranged on the base (20), wherein the heating body (31) forms a heating body array, Wherein, the heating body (31) can work alone to form the desired preheating profile; The preheating device (1) further comprises a shield (40) which is arranged above the heating unit (30) and has a predetermined opening (404), the shape of the opening (404) matching the desired preheating profile, so that heat radiation from the uncovered heating body (31) can be transmitted outward through the opening (404); The shield (40) further comprises an inner section (402) and an outer section (401) arranged on both sides of the opening (404), and a bridge portion (403) connecting the inner section (402) and the outer section (401).

2. The preheating device (1) according to claim 1, characterized in that The bridge portion (403) of the shield (40) is arranged directly above the heating body (31).

3. The preheating device (1) according to claim 1, characterized in that The bridge portion (403) of the shade (40) is arranged between two adjacent heating bodies (31), wherein the height of the bridge portion (403) is lower than the surface where the highest parts of the two heating bodies (31) are located.

4. The preheating device (1) according to any one of claims 1 to 3, characterized in that The height of the heating body (31) can be adjusted.

5. The preheating device (1) according to claim 4, characterized in that The heating body (31) has a spring mechanism so that the height can be adjusted by deformation of the spring mechanism.

6. The preheating device (1) according to claim 4, characterized in that The heating body (31) has a screw mechanism so that the height can be adjusted by rotating the screw mechanism.

7. The preheating device (1) according to claim 4, characterized in that The preheating device (1) is provided with a heat radiation reflection mechanism.

8. The preheating device (1) according to claim 7, characterized in that The heat radiation reflection mechanism is a heat radiation reflection layer or a first heat radiation reflection cover (307) provided at the heating body (31).

9. The preheating device (1) according to claim 7, characterized in that The heat radiation reflection mechanism is a second heat radiation reflection cover arranged at the opening (404) of the shade (40).

10. The preheating device (1) according to claim 4, characterized in that The preheating device (1) also has a control device, which selects and triggers the heating body (31) to be operated.

11. A method for preheating a workpiece in a preheating device (1) according to claim 1, comprising the following steps: Selecting a corresponding heating body (31) from a heating body array formed by individual heating bodies (31) of a heating unit (30) of the preheating device (1) according to the contour of a workpiece to be preheated; Adjusting the height of the heating body (31) to match the height of the contour of the workpiece to be preheated; Placing the workpiece to be preheated above the selected heating body (31); The selected heating body (31) is triggered to work so as to preheat the contour of the workpiece that needs to be preheated.

12. The method according to claim 11, characterized in that The height of the heating body (31) is adjusted by covering the heating unit (30) with a cover (40) having an opening matching the contour of a workpiece to be preheated and pressing down the heating body (31) to deform a spring mechanism of the heating body (31).

13. The method according to claim 11, characterized in that The height of the heating body (31) is adjusted by rotating the screw mechanism.

14. The method according to any one of claims 11 to 13, characterized in that The operation of the heating body (31) is triggered by a control device.

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