A fixture for providing a protective atmosphere for heating a workpiece

Abstract

The application relates to a clamp for providing a protective atmosphere for workpiece heating, a base is provided with a first pressing surface and a first groove, a first flow channel is arranged in the base, a first air port is formed in the side wall of the groove, and a second air port is formed in the side face; a material receiving plate is arranged in the first groove, the material receiving surface is coplanar with the first pressing surface, a first area is arranged on the material receiving surface, a heating port is communicated with a through groove to couple an external heat source; a lower pressing piece is provided with a second pressing surface and a second groove, and is matched with a non-heating part of the workpiece during clamping, so that the two grooves enclose an air cavity in the first area; a second flow channel of the lower pressing piece is provided with a plurality of third air ports in the groove bottom, and the other end is provided with a fourth air port; the third air ports are communicated with the first air ports and the air cavity. Accordingly, a uniform, positive pressure and directional overflow protective atmosphere is established around the part to be heated, the invasion of oxygen / water vapor is inhibited, the oxidation discoloration phenomenon is reduced, and the consistency and yield of wetting, conductivity and heat conduction are improved.

Description

Technical Field

[0001] This invention relates to a clamp, and more particularly to a clamp for providing a protective atmosphere for heating a workpiece. Background Technology

[0002] In processes such as reflow soldering, diffusion soldering / brazing, preformed solder activation, stress-relief annealing, and localized heat treatment, copper and copper alloy workpieces often require rapid heating and temperature stabilization in localized areas (the areas to be heated). These materials are extremely sensitive to oxygen / moisture: at medium to high temperatures, they easily form oxide films and exhibit surface discoloration such as blackening or yellowing, which in turn affects subsequent welding wetting, electrical / thermal conductivity, and appearance pass rate.

[0003] Existing technologies mostly employ whole-furnace protection (box / tunnel / muffle furnace) and N2 / Ar gas filling; or arrange bulky or open hot plates / top covers for local heating and supplemented by single-sided gas injection (e.g., top nozzle, annular nozzle or simple cover); or conventional clamping fixtures have upper and lower pressing surfaces to clamp non-heated parts, but the gas supply and exhaust ports are arranged in a single way (mostly one side gas inlet and overflow).

[0004] The aforementioned solutions generally suffer from drawbacks such as uneven protective gas coverage, difficulty in establishing stable positive pressure and directional overflow in the target area, poor adaptability to workpiece shape, and high gas consumption. Therefore, there is an urgent need to propose a fixture that provides a protective atmosphere for workpiece heating to solve these problems. Summary of the Invention

[0005] The purpose of this invention is to provide a clamp that can simultaneously clamp the non-heated part of the workpiece and create a controlled gas cavity around the heating zone. This environment is characterized by uniform, low-oxygen, stable positive pressure, and directional overflow of protective gas through the coordinated supply / exhaust of the upper and lower opposing, circumferentially multi-point supply and exhaust. This design effectively suppresses high-temperature oxidation and surface discoloration of the copper and copper alloy parts to be heated.

[0006] The technical solution adopted by the present invention to solve the above problems is: a fixture for providing a protective atmosphere for heating a workpiece, the workpiece including a part to be heated and a non-heated part held by the fixture, comprising:

[0007] The base has a first pressing surface, and a first groove is formed on the side of the first pressing surface of the base. A through groove is formed at the bottom of the first groove. A plurality of first flow channels are formed inside the base. One end of the first flow channel extends to the inner side wall of the first groove to form a first air port, and the other end of the first flow channel extends to the side of the base to form a second air port.

[0008] A material support plate has a material support surface, which is disposed in the first groove and the material support surface is coplanar with the first pressing surface; a first region is provided on the material support surface, which includes a heating zone located in the middle and a material support zone arranged around the heating zone; a heating port is provided at the heating zone of the material support plate, which is connected to the through groove for coupling with an external heat source;

[0009] The pressing component has a second pressing surface, and a second groove is formed on the side of the second pressing surface. In the clamping state, the second pressing surface is opposite to the first pressing surface and presses against the non-heated part of the workpiece, so that the first groove and the second groove together form an air cavity in the first area. The pressing component has a plurality of second flow channels. One end of the second flow channel extends to the bottom of the second groove to form a third air port, and the other end of the second flow channel extends to the side of the pressing component to form a fourth air port.

[0010] The number of third air ports is several, and they are evenly distributed in an array along the circumferential area of ​​the bottom of the second groove opposite to the material receiving area, so as to communicate with the air cavity together with the first air ports.

[0011] Preferably, the second air port is connected to a gas source for supplying protective gas, the first air port is used to introduce protective gas into the air chamber, the fourth air port is connected to a pumping device, and the third air port is connected to the air chamber to draw gas from the air chamber.

[0012] Preferably, the first flow channel and the extraction device are respectively provided with a pressure stabilizing / throttling unit. The pressure stabilizing / throttling unit is configured to adjust the air supply flow rate of the first air port to be greater than the extraction flow rate of the third air port under steady state, so that the static pressure in the air chamber is higher than the external air pressure.

[0013] Preferably, the fourth air port is connected to a gas source for supplying protective gas, the third air port is used to introduce protective gas into the air chamber, the second air port is connected to a pumping device, and the first air port is connected to the air chamber to draw gas from the air chamber.

[0014] Preferably, the second flow channel and the extraction device are respectively provided with a pressure stabilizing / throttling unit. The pressure stabilizing / throttling unit is configured to adjust the air supply flow rate of the third air port to be greater than the extraction flow rate of the first air port under steady state, so that the static pressure in the air chamber is higher than the external air pressure.

[0015] Preferably, an annular sealing ring and / or a labyrinth gap are provided between the outer periphery of the second groove and the outer periphery of the first groove, and an adjustable pressure stabilizing / throttling unit is provided between the first flow channel and the extraction device, so that the air chamber always maintains a positive pressure relative to the outside during operation.

[0016] Preferably, both the second and fourth air ports are connected to a gas source for supplying protective gas, and both the first and third air ports are used to introduce protective gas into the air cavity.

[0017] Preferably, an annular guide groove and / or a row of pressure relief holes are provided at the bottom of the second groove corresponding to the outer edge of the first region. The guide groove or row of pressure relief holes is connected to the outside of the fixture to form a directional pressure relief overflow path.

[0018] Preferably, the first flow channel and the second flow channel are respectively provided with adjustable flow rate throttling / pressure stabilizing units. The throttling / pressure stabilizing units are configured to make the total air supply flow rate of the first air port and the third air port greater than the flow rate overflowing through the pressure relief overflow path under steady state, so that the static pressure in the air chamber is higher than the external air pressure.

[0019] Preferably, the fixture further includes a pressure sensing element and a valve control unit; the sensing end of the pressure sensing element is connected to the air chamber, and the signal output end of the pressure sensing element is electrically connected to the valve control unit; the valve control unit is electrically connected to a throttling / pressure stabilizing unit disposed on the first flow channel and / or the second flow channel; the valve control unit is configured to adjust the opening of the throttling / pressure stabilizing unit according to the static pressure of the air chamber detected by the pressure sensing element, so that the total flow rate entering the air chamber in steady state is greater than the total flow rate overflowing through the pressure relief overflow path, and to maintain the static pressure in the air chamber within a set range higher than the external air pressure.

[0020] The beneficial effects of the embodiments of the present invention are as follows:

[0021] Because this invention employs techniques such as forming a first groove and a second groove on the base and the lower pressure member respectively, and jointly enclosing an air cavity in the first area of ​​the material-bearing surface; setting a first air port on the inner sidewall of the first groove; and evenly distributing a third air port in the circumferential area opposite to the material-bearing area along the bottom edge of the second groove; and achieving efficient coupling of the external heat source to the heating area through the through groove-heating port, it can establish a uniform, stable, positive pressure, and directional overflow protective gas environment around the part to be heated. This suppresses the entrainment of gaps and the intrusion of oxygen / water vapor from the source, effectively solving the technical problems of uneven protective gas coverage, difficulty in maintaining stable positive pressure and directional overflow, poor adaptability to workpiece shape, and high gas consumption caused by existing whole furnace gas filling, open single-sided jetting, or single supply and exhaust port arrangements. Thus, it achieves the technical effects of suppressing high-temperature oxidation and surface discoloration of copper and copper alloy parts to be heated, improving welding wetting and electrical / thermal conductivity consistency, improving process yield and repeatability, and enhancing adaptability to workpieces with different shapes without increasing the overall line size and gas consumption. Attached Figure Description

[0022] Figure 1A schematic top view of the base according to an embodiment of the present invention is shown.

[0023] Figure 2 A schematic side sectional view of the base in one embodiment of the present invention is shown.

[0024] Figure 3 A schematic top view of a material support plate according to an embodiment of the present invention is shown.

[0025] Figure 4 A schematic top view of a workpiece placed on a support plate according to an embodiment of the present invention is shown.

[0026] Figure 5 A schematic bottom view of the lower pressure member in one embodiment of the present invention is shown.

[0027] Figure 6 A schematic side view of the lower pressure member in one embodiment of the present invention is shown.

[0028] Figure 7 A schematic bottom view is shown in one embodiment of the present invention when the workpiece is located in the second groove.

[0029] Figure 8 A schematic top view of a workpiece according to an embodiment of the present invention is shown.

[0030] Figure 9 A schematic side view of a workpiece according to an embodiment of the present invention is shown.

[0031] Wherein: 10, base; 110, first pressing surface; 120, first groove; 130, through groove; 140, second air port; 150, first air port; 20, material support plate; 210, material support surface; 220, first area; 221, heating area; 222, material support area; 230, heating port; 30, pressing part; 310, second pressing surface; 320, second groove; 330, third air port; 40, workpiece; 410, part to be heated; 420, non-heated part. Detailed Implementation

[0032] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0033] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the scope of protection of this application. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0034] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art will understand the specific meaning of the above terms in this application based on the specific circumstances.

[0035] Figure 8 A schematic top view of a workpiece according to an embodiment of the present invention is shown; Figure 9 A schematic side view of a workpiece according to an embodiment of the present invention is shown. Please refer to... Figures 8 to 9 A preferred embodiment of this application provides a fixture for providing a protective atmosphere for heating a workpiece 40. The target workpiece 40 is a copper alloy, and its specific structure, as shown in the figure, includes a portion 410 to be heated and a non-heated portion 420 held by the fixture.

[0036] Figure 1 A schematic top view of the base in one embodiment of the present invention is shown; Figure 2 A schematic side sectional view of the base in one embodiment of the present invention is shown; Figure 3 A schematic top view of a material support plate according to an embodiment of the present invention is shown; Figure 4 A schematic top view of a workpiece placed on a support plate according to an embodiment of the present invention is shown. Figure 5 A schematic bottom view of the lower pressing member in one embodiment of the present invention is shown; Figure 6 A schematic side view of the lower pressing member is shown in one embodiment of the present invention; Figure 7A schematic bottom view is shown in one embodiment of the present invention, showing the workpiece located within the second groove. Please refer to... Figures 1 to 7 The fixture includes a base 10, a support plate 20, and a pressing member 30. The base 10 has a first pressing surface 110, and a first groove 120 is formed on the side of the first pressing surface 110. A through groove 130 is formed at the bottom of the first groove 120. The base 10 has several first flow channels, one end of which extends to the inner wall of the first groove 120 to form a first air vent 150, and the other end extends to the side of the base 10 to form a second air vent 140. The support plate 20 has a support surface 210, which is disposed within the first groove 120 and is coplanar with the first pressing surface 110. The support surface 210 has a first region 220, which includes a heating zone 221 located in the center and a support zone 22 surrounding the heating zone 221. 2; The heating zone 221 of the material support plate 20 is provided with a heating port 230, which is connected to the through groove 130 for coupling with an external heat source; The pressing member 30 has a second pressing surface 310, and a second groove 320 is opened on the side of the second pressing surface 310; In the clamping state, the second pressing surface 310 is opposite to the first pressing surface 110 and presses and cooperates with the non-heated part 420 of the workpiece 40, so that the first groove 120 and the second groove 320 are jointly enclosed in the first area 220 to form an air cavity; The pressing member 30 is provided with a plurality of second flow channels, one end of the second flow channel extends to the bottom of the groove 320 to form a third air port 330, and the other end of the second flow channel extends to the side of the pressing member 30 to form a fourth air port (not shown in the figure). The number of the third air ports 330 is several, and they are evenly distributed in an array along the circumferential area of ​​the bottom of the second groove 320 opposite to the material receiving area 222, so as to communicate with the air cavity together with the first air port 150.

[0037] Specifically:

[0038] The base 10 is provided with a first pressing surface 110, and a first groove 120 is formed on the side of the first pressing surface 110. The through groove 130 at the bottom of the first groove 120 extends along the thickness direction as a thermal coupling channel.

[0039] The base 10 has several first flow channels arranged inside. The first flow channels have first air ports 150 facing the inner wall of the first groove 120, and second air ports 140 are led out towards the side of the base 10 so as to connect with external pipelines.

[0040] The material support plate 20 is assembled in the first groove 120, and the material support surface 210 is substantially coplanar with the first pressing surface 110. The material support surface 210 defines a first region 220, the center of which is a heating zone 221, and the surrounding area is a material support zone 222. The material support plate 20 has a heating port 230 at the heating zone 221, which is connected to the through groove 130 to achieve efficient coupling of the external heat source.

[0041] The pressing member 30 has a second pressing surface 310, and a second groove 320 is formed on the side of the second pressing surface 310. In the clamping state, the second pressing surface 310 is opposite to the first pressing surface 110 and presses against the non-heated part 420 of the workpiece 40. The first groove 120 and the second groove 320 together form an air cavity in the first region 220. Several second flow channels are provided inside the pressing member 30. The second flow channels form a third air port 330 facing the bottom of the second groove 320, and a fourth air port is led out towards the side of the pressing member 30. The third air ports 330 are evenly distributed in an array along the circumferential area of ​​the bottom of the second groove 320 opposite to the material receiving area 222, and communicate with the air cavity together with the first air port 150, thereby establishing a uniform gas coverage around the part to be heated 410. Each component can be made of heat-resistant metal or composite material, and the mating surfaces are precision machined to ensure assembly accuracy and surface quality. The material receiving plate 20 can be an integral part or a replaceable part to adapt to different workpiece 40 shapes.

[0042] During use, the workpiece 40 is placed on the receiving surface 210, with the part to be heated 410 corresponding to the heating zone 221, and the non-heated part 420 positioned between the two pressing surfaces to form a reliable clamping. Protective gas is supplied or drawn from the first and second flow channels through external pipelines. The first gas port 150 supplies gas into the gas chamber from the side wall, and the third gas port 330 distributes gas circumferentially from the bottom of the tank. Together, they form a uniformly covered protective gas field around the first area 220. External heat source energy is coupled to the heating zone 221 through the through groove 130 and the heating port 230, achieving localized heating and heat preservation. After the operation is completed, the gas supply and heating are stopped. Once the workpiece 40 has cooled to the allowable temperature, the lower pressure piece 30 is released, and the workpiece 40 is removed.

[0043] The key design feature of this embodiment lies in the relative enclosure of the first groove 120 and the second groove 320, which ensures the formation of a controlled air cavity in the first region 220. The coplanar relationship between the material-bearing surface 210 and the first pressing surface 110 ensures the stability of the workpiece 40's positioning. The first air port 150 supplies air from the side wall, and the third air port 330 distributes air along the circumferential array at the bottom of the groove, working together to cover the area. The superposition of the two improves the uniformity of coverage. The through groove 130 and the heating port 230 form a thermal coupling path, ensuring that energy directly acts on the heating zone 221 and reducing the thermal impact on the clamping part. The second air port 140 and the fourth air port serve as external ports, facilitating the configuration and switching of supply and discharge with external pipelines. During assembly, it is essential to ensure the parallelism of the two pressing surfaces and the reliable positioning of the material-bearing plate 20 to avoid uneven flow field caused by clamping offset.

[0044] This embodiment is applicable to production scenarios involving localized heating of easily oxidized materials such as copper alloys, and is particularly suitable for situations requiring low oxygen protection within a limited clamping space and stable cycle time. The environment should be kept clean and dry, and the external pipeline should meet the requirements for clean gas supply and stable flow. The heat source can be either contact or non-contact, and the fixture can be adapted to workpieces 40 with different shapes and sizes by replacing the support plate 20.

[0045] In some optional embodiments, the array of the third air inlets 330 can be a single ring or multiple rings, or it can be staggered to improve circumferential uniformity. The first flow channel can be a single-path or multi-path structure, and a diffuser section can be provided near the first air inlet 150 to slow down the jet velocity. The heating port 230 can be used with heat source coupling components of different shapes, and the through groove 130 and the material support plate 20 can be of integral or separate structure for easy maintenance and replacement. The base 10 and the pressing component 30 can be made of materials with different thermal expansion characteristics to balance thermal deformation and maintain fitting accuracy.

[0046] In this embodiment, by employing the technical means of base 10 and pressing member 30 jointly enclosing an air cavity in the first region 220, supplying air from the side wall through the first air port 150 and coordinating air distribution along the circumferential array of the third air port 330 at the bottom of the groove, and achieving efficient coupling of the external heat source between the through groove 130 and the heating port 230, a protective gas environment with uniform coverage, stable positive pressure, and directional overflow characteristics can be established around the part to be heated 410. This effectively solves the technical problems of uneven gas coverage, difficulty in maintaining stable low oxygen content, and insufficient clamping adaptability in the existing solutions, thereby achieving the technical effects of suppressing high-temperature oxidation and surface discoloration, improving heating consistency and subsequent process repeatability, and taking into account energy consumption and cycle time.

[0047] In the first embodiment, the second air port 140 is connected to a gas source for supplying protective gas, the first air port 150 is used to introduce protective gas into the air chamber, the fourth air port is connected to an extraction device, and the third air port 330 is connected to the air chamber to draw gas from the air chamber. The first flow channel and the extraction device are each equipped with a pressure stabilizing / throttling unit. The pressure stabilizing / throttling unit is configured to adjust the gas supply flow rate of the first air port 150 to be greater than the extraction flow rate of the third air port 330 under steady-state conditions, so that the static pressure in the air chamber is higher than the external air pressure.

[0048] Specifically:

[0049] The base 10 has several first flow channels arranged inside. Each first flow channel has a first air port 150 facing the inner wall of the first groove 120, and a second air port 140 extending towards the side of the base 10 for connection to an external air source. The material support plate 20 is assembled within the first groove 120, with its material support surface 210 substantially coplanar with the first pressing surface 110. The material support surface 210 defines a first region 220, the center of which is a heating zone 221, and the surrounding area is a material support zone 222. The pressing member 30 has several second flow channels inside. Each second flow channel forms a third air port 330 facing the bottom of the second groove 320, and a fourth air port extending towards the side of the pressing member 30. The third air ports 330 are evenly distributed in an array along the circumferential area of ​​the bottom of the second groove 320 opposite to the material support zone 222, so that they communicate with the air cavity together with the first air ports 150. Each mating surface is preferably precision-processed to obtain a stable bonding relationship. The support plate 20 can be made of heat-resistant and thermally conductive metal or composite material to meet both support and heat conduction requirements.

[0050] The workpiece 40 is placed on the receiving surface 210, so that the part to be heated 410 corresponds to the heating zone 221 where the heating port 230 is located. After the lower pressing part 30 is closed, it forms a reliable clamping of the non-heated part 420, and a controlled air cavity is formed in the first region 220. The second air port 140 is connected to a protective gas source, so that the gas enters the air cavity through the first flow channel and the first air port 150. The fourth air port is connected to the extraction device, so that the gas in the air cavity is drawn into the second flow channel through the third air port 330 and discharged through the fourth air port. The first flow channel and the extraction device are respectively equipped with pressure stabilizing and throttling units, which are used to adjust the gas supply flow rate of the first air port 150 to be greater than the extraction flow rate of the third air port 330 under steady state, thereby maintaining the positive pressure state of the air cavity relative to the outside. The external heat source energy is coupled to the heating zone 221 through the through groove 130 and the heating port 230 to complete the heating, heat preservation and cooling process.

[0051] The key to the first embodiment lies in the fact that the opposing arrangement of the first groove 120 and the second groove 320 defines the geometric boundary of the air cavity, and the coplanar relationship between the material-bearing surface 210 and the first pressing surface 110 ensures the stability of the relative position between the part to be heated 410 and the supply and exhaust areas. The first air port 150 is located on the inner wall of the first groove 120 and can form a surface sweep flow, which helps to guide the gas entering the air cavity to the periphery of the part to be heated 410; the third air port 330 is evenly distributed in a circumferential array along the bottom of the second groove 320, which can evenly draw the gas in the air cavity from above, promoting a more uniform flow field distribution in the cavity. The pressure stabilization and throttling units, through the synergistic constraint of the supply and exhaust ratio, ensure that the cavity maintains a positive pressure characteristic, reducing the risk of backflow of external air from the boundary gaps. The through groove 130 and the heating port 230 form a direct thermal coupling path, reducing the thermal impact on the clamping part and ensuring heating efficiency and temperature field stability.

[0052] In some optional embodiments, the first flow channel may be provided with a diffuser section or a microporous throttling component near the first air port 150 to reduce the jet velocity and improve the uniformity within the cavity; the array of the third air port 330 may be optimized in density and partitioning in the circumferential direction according to the shape of the workpiece 40 to adapt to different material receiving area 222 contours; the pressure stabilizing and throttling unit may adopt an elastic thin film type pressure stabilizing structure or a porous plate type impedance structure to meet different flow rate and pressure settings; a heat-conducting block or a radiation window type coupling component may be used between the external heat source and the heating port 230 to improve energy transfer efficiency.

[0053] In this embodiment, by employing the technical means of connecting the second air port 140 to the air source, sending protective gas into the air chamber through the first air port 150, connecting the fourth air port to the extraction device and drawing gas from the air chamber through the third air port 330, and setting pressure stabilizing and throttling units on the first flow channel and the extraction device to maintain positive pressure in the chamber, a uniform and stable low-oxygen protective environment can be formed around the part to be heated 410. This effectively solves the problems of uneven coverage and backflow of external gas caused by single-sided jetting or a single arrangement of supply and exhaust ports, thereby achieving the technical effects of suppressing high-temperature oxidation and surface discoloration, improving heating consistency and subsequent process stability.

[0054] Furthermore, it should be noted that the flow direction of the bottom-feeding and top-extraction is in line with the natural buoyancy of the heated gas and the direction of the hot plume. This is conducive to the rapid removal of water vapor and volatiles above the heating zone 221, reducing the risk of eddy entrainment and redeposition. At the same time, it makes it easier for low-oxygen gas to maintain positive pressure coverage near the heating zone 221, thereby achieving a better balance between gas consumption and temperature uniformity.

[0055] In the second embodiment, the fourth air port is connected to a gas source for supplying protective gas, the third air port 330 is used to introduce protective gas into the air chamber, the second air port 140 is connected to an extraction device, and the first air port 150 is connected to the air chamber to draw gas from the air chamber. The second flow channel and the extraction device are each equipped with a pressure stabilizing / throttling unit. The pressure stabilizing / throttling unit is configured to adjust the gas supply flow rate of the third air port 330 to be greater than the extraction flow rate of the first air port 150 under steady-state conditions, so that the static pressure in the air chamber is higher than the external air pressure.

[0056] Specifically:

[0057] A first flow channel is provided inside the base 10. A first air port 150 is formed on the inner wall of the first groove 120, and a second air port 140 is formed on the side of the base 10 for connection to external pipelines. A second flow channel is provided inside the pressing member 30. A third air port 330 is formed on the bottom of the second groove 320, and a fourth air port is formed on the side of the pressing member 30. The third air ports 330 are arrayed along the circumferential area of ​​the bottom of the second groove 320 opposite to the material receiving area 222, for uniform gas distribution to the area above the air chamber. The second air port 140 is connected to a protective gas source via a pipeline, and the fourth air port is connected to a gas extraction device via a pipeline. The first air port 150 and the third air port 330 are directly connected to the air chamber. A pressure stabilizing and throttling unit is configured between the second flow channel and the extraction device to set and maintain the flow resistance and flow range on the extraction side.

[0058] The workpiece 40 is placed on the receiving surface 210, so that the part to be heated 410 corresponds to the heating area 221. After the pressing part 30 is closed, the first groove 120 and the second groove 320 enclose each other in the first area 220 to form an air cavity. The air source is turned on, and air is supplied to the second flow channel through the fourth air port. Protective gas enters the area above the air cavity from the third air port 330 to form a cover. At the same time, the exhaust device is turned on, and it is connected to the external exhaust through the second air port 140. The gas in the air cavity is introduced into the first flow channel through the first air port 150 and discharged. The exhaust side impedance is adjusted by the pressure stabilization and throttling unit so that the air supply flow rate of the third air port 330 is greater than the exhaust flow rate of the first air port 150 in steady state, thereby establishing a positive pressure environment relative to the outside in the air cavity and maintaining an orderly overflow characteristic.

[0059] The key to the second embodiment lies in the fact that the third air port 330 is located in the circumferential region of the bottom of the second groove 320, which can form a uniform air supply band above the heating zone 221; the first air port 150 is located on the inner sidewall of the first groove 120, which facilitates the guidance of gas away from the gas chamber in the area near the material receiving surface 210. The second air port 140 and the fourth air port serve as external ports for extraction and supply, respectively, and together with the pressure stabilization and throttling units, they form an adjustable supply-extraction ratio control link. Through the above relative arrangement, a protective gas field with uniform coverage and stable pressure can be established around the heating zone 221.

[0060] In some optional embodiments, the third air port 330 may be a single ring or multi-ring array, and a diffusion component may be provided to reduce the jet velocity and improve the coverage uniformity; a buffer section may be provided at the front end of the first air port 150 to smooth the backflow field; the pressure stabilization and throttling unit may be a needle valve type, diaphragm type or perforated plate type structure to meet different flow rate and pressure settings; vibration damping and buffer components may be added to the pipelines of the second air port 140 and the fourth air port to reduce the impact of pressure fluctuations on the flow field.

[0061] In this embodiment, by employing a fourth air port connected to the air source to supply air to the third air port 330 via the second flow channel, a second air port 140 connected to the extraction device to draw air back from the air chamber via the first air port 150, and a pressure stabilizing and throttling unit set between the second flow channel and the extraction device to ensure that the air supply flow rate of the third air port 330 is greater than the extraction flow rate of the first air port 150 under steady state, thereby maintaining positive pressure in the air chamber, the existing technical problems such as uneven coverage and backflow of external gas caused by unilateral air supply or imbalance of supply and exhaust ratio are effectively solved. This achieves the technical effect of forming a uniform and stable protective gas curtain above the heating zone 221 and maintaining positive pressure throughout the air chamber.

[0062] It should be noted that this embodiment adopts a top-down gas flow direction, which can preferentially form an air curtain above the heating zone 221, directly shielding the seepage of the gap at the upper boundary. At the same time, the water vapor and volatile components generated by heating are pressed along a predetermined path to the lower return end, reducing the roll-back and retention near the hot zone, reducing the peak value of convective cooling and helping to maintain the consistency of temperature and atmosphere, thereby achieving a better balance between protection effect, gas consumption and thermal uniformity.

[0063] Based on the first and second embodiments described above, an annular sealing ring and / or a labyrinth gap are provided between the outer periphery of the second groove 320 and the outer periphery of the first groove 120, and an adjustable pressure stabilizing / throttling unit is provided between the first flow channel and the extraction device, so that the air chamber always maintains a positive pressure relative to the outside during operation.

[0064] Specifically:

[0065] The annular sealing ring is embedded in the opposing annular steps or grooves. In the clamping state, it is axially pressed by the two pressing surfaces and produces continuous circumferential contact to form the first elastic sealing boundary between the air cavity and the outside.

[0066] The labyrinth gap is formed by overlapping annular ribs and annular steps, which alternately turn radially and axially to form a multi-level slender flow channel from the inside to the outside, used to limit the controlled overflow path and extend the equivalent length of the discharge channel.

[0067] An adjustable pressure stabilizing and throttling unit is installed on the connecting pipeline between the first flow channel and the extraction device. This pressure stabilizing and throttling unit is integrated with the first flow channel or adopts a series valve body structure and is connected to the inlet or pipeline of the extraction device. By adjusting the flow resistance, the supply and discharge ratio is set to ensure that the gas chamber is in a positive pressure state relative to the outside when it is working.

[0068] The sealing ring is preferably made of heat-resistant elastic material, and the labyrinth component is a heat-resistant ring that is integrally machined with the base or is replaceable. The contact surface is finely machined to obtain a stable fit and uniform compression.

[0069] During assembly, the annular sealing ring is positioned and aligned with the annular steps on both sides. After the clamps are closed, the sealing ring is axially compressed to form a circumferential elastic seal. Gas enters the gas chamber through the first flow channel and, driven by positive pressure, slowly overflows along the predetermined path of the labyrinth gap, making it difficult for external gas to enter in reverse. The extraction side uses an adjustable pressure stabilizing and throttling unit to set the extraction flow resistance, ensuring that the static pressure inside the gas chamber is higher than the ambient pressure and maintaining a stable overflow, preventing backflow at the boundary. After operation, the clamping is released, the sealing ring springs back, and the labyrinth component retains its original gap shape, facilitating reuse.

[0070] The key to this embodiment lies in the following: the annular sealing ring provides the first elastic seal, ensuring airtightness during pressure differential fluctuations; the labyrinth gap provides the second throttling, determining the overflow direction and discharge rate; and the adjustable pressure stabilizing and throttling unit, by changing the flow resistance on the extraction side or its connected pipeline, in conjunction with the flow rate setting on the supply side, stabilizes the static pressure of the gas chamber within the target range. These three elements work together to form a closed loop of sealing, throttling, and positive pressure control, ensuring that controlled overflow occurs only along the labyrinth path and suppressing boundary entrainment.

[0071] In some optional embodiments, the annular sealing ring can be a circular cross-section, lip-shaped, or encapsulated structure, and its installation position can be arranged in the annular groove on the side of the first groove 120 or the side of the second groove 320; the labyrinth clearance can adopt a stepped, sawtooth, or tortuous channel layout, and a collection groove is provided on the outside to guide the overflow gas to be discharged in a directional manner; the adjustable pressure stabilizing and throttling unit can be a needle valve type, diaphragm type, or multi-hole throttling type, and can be combined with pipeline quick couplings for maintenance and replacement. All of the above components can be modularly designed, which facilitates flexible combination for different working conditions.

[0072] In this embodiment, by employing a technique of setting an annular sealing ring and a labyrinth gap between the outer peripheries of the two grooves and configuring an adjustable pressure stabilizing and throttling unit between the first flow channel and the extraction device to maintain a positive pressure in the gas chamber relative to the outside during operation, the existing technical problems such as backflow at the boundary, entrainment of external gas, and instability of the protective airflow field are effectively solved. This achieves the technical effects of ensuring reliable sealing while forming a controllable overflow path, stabilizing the positive pressure of the gas chamber, providing uniform protective coverage, and improving the consistency and repeatability of the heating process.

[0073] In the third embodiment, both the second air port 140 and the fourth air port are connected to a gas source for supplying protective gas, and both the first air port 150 and the third air port 330 are used to introduce protective gas into the air cavity. An annular guide groove and / or a row of pressure relief holes are provided at the bottom of the second groove 320 corresponding to the outer edge of the first region 220. The guide groove or row of pressure relief holes is connected to the outside of the fixture to form a directional pressure relief overflow path. The first flow channel and the second flow channel are respectively provided with adjustable flow rate throttling / pressure stabilizing units. The throttling / pressure stabilizing units are configured to ensure that, under steady-state conditions, the total gas supply flow rate of the first air port 150 and the third air port 330 is greater than the flow rate overflowing through the pressure relief overflow path, thereby making the static pressure inside the air cavity higher than the external air pressure.

[0074] Specifically:

[0075] The second air port 140 is connected to the air source for supplying protective gas, and the fourth air port is also connected to the air source; the first air port 150 and the third air port 330 are respectively disposed on the inner side wall of the first groove 120 and the bottom of the second groove 320, and are both connected to the air cavity to introduce protective gas into the air cavity, thereby realizing bidirectional air supply from bottom to top.

[0076] The bottom of the second groove 320 forms an annular guide groove corresponding to the outer edge of the first region 220. Alternatively, several pressure relief hole arrays can be provided. The guide groove or pressure relief hole arrays are connected to the outside of the fixture, serving as a directional pressure relief overflow path.

[0077] The first and second flow channels are respectively equipped with adjustable flow throttling and pressure stabilizing units, which are used to set and maintain their respective air supply resistance and flow range, so that the total air supply entering the air chamber is greater than the flow overflowing through the pressure relief path, thereby establishing and maintaining a positive pressure environment relative to the outside world.

[0078] The flow channel can be an open annular channel or a stepped composite channel, and the pressure relief hole array can be arranged equidistantly or in zones along the circumference to obtain a uniform overflow ring to match the boundary morphology of different workpieces.

[0079] Workpiece 40 is positioned on the support surface 210, aligning the heated part 410 with the first region 220. After the gas source is turned on, protective gas enters the first and second flow channels through the second and fourth gas ports, respectively, and is simultaneously injected into the gas cavity through the first and third gas ports 150 and 330, forming a bidirectional coverage field from bottom to top and top to bottom. The gas inside the cavity overflows directionally to the outside of the fixture at the outer edge of the first region 220 along an annular guide groove or through a row of pressure relief holes. By adjusting the throttling and pressure stabilizing units on the first and second flow channels, the upper and lower gas supply is balanced, and the total supply is maintained at a level higher than the directional overflow, stably forming a positive pressure. This ratio is maintained during heating, heat preservation, and cooling processes to ensure coverage and a low oxygen content around the heated zone 221.

[0080] The key to the third embodiment lies in the geometrical clamping effect of the opposing arrangement of the first air port 150 and the third air port 330 on the heating zone 221, significantly shortening the transmission path of fresh gas to the target area; the annular guide groove or pressure relief hole array defines the overflow position and direction, suppressing disordered leakage and entrainment at the boundary; the throttling and pressure stabilizing unit achieves quantitative balancing of bidirectional air supply by changing the equivalent flow resistance of the upper and lower channels, thus controlling the static pressure in the cavity and the overflow rate. The three elements work together to form a flow field structure with uniform coverage, directional overflow, and constant positive pressure centered on the heating zone 221.

[0081] In some alternative embodiments, the annular guide groove can be narrow and deep or wide and shallow to match different overflow impedances; the pressure relief hole array can be a single ring or multiple rings and can be staggered to improve circumferential uniformity. A diffuser section can be added to the front end of the first air port 150 and the third air port 330 to reduce the peak jet velocity and further improve coverage uniformity.

[0082] In this embodiment, by employing a dual-path synchronous gas supply, arranging an annular guide groove or pressure relief hole array at the outer edge of the first region 220 to form a directional overflow path, and configuring adjustable flow throttling and pressure stabilizing units on the two flow channels to ensure that the total gas supply is greater than the overflow, thereby maintaining positive pressure inside the cavity, the existing technical problems such as uneven coverage and backflow caused by single-sided gas supply are effectively solved. This achieves the technical effect of forming a uniform, stable, and low-oxygen protective atmosphere around the heated part 410 and maintaining orderly overflow and constant positive pressure.

[0083] It should be noted that the bidirectional flow arrangement in this embodiment can distribute the gas supply kinetic energy on both the upper and lower sides, reduce the intensity of local jet scouring and eddy currents, shorten the path of fresh gas to the heating zone 221 and improve the replacement efficiency; at the same time, the directional overflow ring unifies the venting position and direction, suppresses disordered side leakage and entrainment, and makes the temperature field and atmosphere field more balanced, which is conducive to reducing gas consumption and improving the consistency and repeatability of the heating process.

[0084] Furthermore, the fixture also includes a pressure detection element and a valve control unit; the detection end of the pressure detection element is connected to the air chamber, and the signal output end of the pressure detection element is electrically connected to the valve control unit; the valve control unit is electrically connected to a throttling / pressure stabilizing unit disposed on the first flow channel and / or the second flow channel; the valve control unit is configured to adjust the opening of the throttling / pressure stabilizing unit according to the static pressure of the air chamber detected by the pressure detection element, so that the total flow rate entering the air chamber under steady state is greater than the total flow rate overflowing through the pressure relief overflow path, and to maintain the static pressure in the air chamber within a set range higher than the external air pressure.

[0085] Specifically:

[0086] Based on the third embodiment, the fixture is further equipped with a pressure detection element and a valve control unit. The detection end of the pressure detection element is connected to the gas chamber through a detection hole or conduit, preferably located in a static pressure zone away from the jet impact, and fixed to the fixture body with a sealed joint. The length and inner diameter of the conduit are selected according to the principles of low impedance and low hysteresis. The signal output end of the pressure detection element is electrically connected to the valve control unit via a shielded cable. The valve control unit is mounted on the side wall of the fixture or on an independent mounting bracket and is electrically connected to the throttling and stabilizing unit on the first flow channel and / or the second flow channel. The throttling and stabilizing unit adopts an adjustable structure and can be an electric needle valve, a proportional diaphragm assembly, or a porous damping mechanism, and is connected in series with the corresponding flow channel. The displacement of the valve stem or diaphragm is driven by the valve control unit. The valve control unit has a built-in target chamber pressure setting, filtering, and opening conversion module, and has failure self-locking and limit protection functions. The power supply and grounding are separately led out according to anti-interference requirements.

[0087] Before operation, the target cavity pressure and allowable bandwidth are set. After the gas source is turned on, pre-purification is performed. The valve control unit collects the static pressure signal of the gas cavity from the pressure detection element in real time. After filtering and comparison, the deviation is obtained, and the target opening degree of the throttling and pressure stabilizing unit of the first flow channel and / or the second flow channel is calculated and driven to ensure that the total flow rate entering the gas cavity is greater than the total flow rate overflowing through the directional pressure relief overflow path, forming and maintaining a positive pressure relative to the outside. During the heating and heat preservation stages, the valve control unit dynamically fine-tunes the opening degree according to the static pressure change to suppress the influence of load disturbance and pipeline fluctuation on the cavity pressure. During the cooling stage, the gas supply is reduced at a predetermined slope and positive pressure is maintained until the cavity temperature drops to the allowable value, after which it is shut off in an orderly manner. Throughout the process, the communication channel at the detection end remains unobstructed to avoid condensation and particle blockage.

[0088] The key to this embodiment lies in the fact that the pressure tapping position at the detection end determines the accuracy of the static pressure measurement, and it is necessary to avoid the near-jet zone of the first air port 150 and the third air port 330. The response time of the valve control unit and the flow resistance characteristics of the throttling and pressure stabilizing units together determine the closed-loop time constant. The opening adjustment amount should be monotonically controllable with the cavity pressure change to prevent overshoot and oscillation. The opening distribution of the first flow channel and the second flow channel affects the momentum of the upper and lower air supply and the uniformity of the flow field in the cavity. The valve control unit can use a distribution coefficient to coordinate the adjustment of the two channels to make the cavity pressure and the flow rate of the overflow path match stably.

[0089] In some optional embodiments, the pressure sensing element can be a diaphragm type, capacitive type, or piezoresistive type, and the sensing end can be averaged through a microporous plate or static pressure chamber; the valve control unit can integrate a setting and display interface or be connected to a higher-level control system; the throttling and pressure stabilizing unit can use a parallel microporous array to obtain near-linear flow characteristics; if only one of the first flow channel and the second flow channel has adjustable capability, the valve control unit can also be adjusted in a single channel and the other flow channel can be set to constant resistance; a pressure loss bypass can be added to maintain a limited positive pressure in the event of an abnormal power failure.

[0090] In this embodiment, a closed-loop control system consisting of a pressure detection element and a valve control unit is adopted. The detection end is connected to the gas chamber, and the valve control unit is electrically connected to the throttling and pressure stabilizing unit on the first and / or second flow channels. The opening is adjusted in real time according to the static pressure of the gas chamber to make the total flow rate entering the gas chamber greater than the total flow rate overflowing through the pressure relief overflow path, and to maintain the static pressure of the gas chamber within a set range higher than the external gas pressure. Therefore, this technical means effectively solves the existing technical problems such as pressure drift, backflow, and uneven coverage when relying on manual setting or open-loop mixing. As a result, it achieves the technical effect of maintaining stable positive pressure and uniform protective atmosphere under load changes and operating condition disturbances, improving process consistency and yield, and reducing debugging and maintenance costs.

[0091] The above description is merely illustrative of the invention. Those skilled in the art can make various modifications or additions to the described specific embodiments or use similar methods to replace them, as long as they do not depart from the content of this specification or exceed the scope defined by the claims, all of which should fall within the protection scope of this invention.

Claims

1. A fixture for providing a protective atmosphere for heating a workpiece, the workpiece comprising a portion to be heated and a non-heated portion held by the fixture, characterized in that, include: The base has a first pressing surface, and a first groove is formed on the side of the first pressing surface of the base. A through groove is formed at the bottom of the first groove. A plurality of first flow channels are formed inside the base. One end of the first flow channel extends to the inner side wall of the first groove to form a first air port, and the other end of the first flow channel extends to the side of the base to form a second air port. A material support plate has a material support surface, which is disposed in the first groove and the material support surface and the first pressing surface are located in the same plane; the material support surface is provided with a first region, which includes a heating zone located in the middle and a material support zone arranged around the heating zone; the heating zone of the material support plate is provided with a heating port, which is connected to the through groove for coupling with an external heat source; The pressing component has a second pressing surface, and a second groove is formed on the side of the second pressing surface. In the clamping state, the second pressing surface is opposite to the first pressing surface and presses against the non-heated part of the workpiece, so that the first groove and the second groove together form an air cavity in the first area. The pressing component has a plurality of second flow channels. One end of the second flow channel extends to the bottom of the second groove to form a third air port, and the other end of the second flow channel extends to the side of the pressing component to form a fourth air port. The number of third air ports is several, and they are evenly distributed in an array along the circumferential region of the bottom of the second groove opposite to the material receiving area; both the first air port and the third air port are connected to the air cavity, and the clamp is provided with an external pipeline connected to an air source and / or a pumping device, so that the total flow rate entering the air cavity under steady state is greater than the overflow flow rate at the boundary when the first pressing surface and the second pressing surface are closed, so that the static pressure of the air cavity is higher than the external air pressure.

2. The clamp according to claim 1, characterized in that, The second air port is connected to a gas source for supplying protective gas, the first air port is used to introduce protective gas into the air chamber, the fourth air port is connected to a pumping device, and the third air port is connected to the air chamber to draw gas from the air chamber.

3. The clamp according to claim 2, characterized in that, A pressure stabilizing / throttling unit is installed on the first flow channel and on the extraction pipeline connected to the fourth air port, respectively. The pressure stabilizing / throttling unit is configured to adjust the air supply flow rate of the first air port to be greater than the extraction flow rate of the third air port under steady state, so that the static pressure in the air chamber is higher than the external air pressure.

4. The clamp according to claim 1, characterized in that, The fourth air port is connected to a gas source for supplying protective gas, the third air port is used to introduce protective gas into the air chamber, the second air port is connected to a pumping device, and the first air port is connected to the air chamber to draw gas from the air chamber.

5. The clamp according to claim 4, characterized in that, A pressure stabilizing / throttling unit is installed on the second flow channel and on the extraction pipeline connected to the second air port, respectively. The pressure stabilizing / throttling unit is configured to adjust the air supply flow rate of the third air port to be greater than the extraction flow rate of the first air port under steady state, so that the static pressure in the air chamber is higher than the external air pressure.

6. The clamp according to any one of claims 1 to 5, characterized in that, An annular sealing ring and / or a labyrinth gap are provided between the outer periphery of the second groove and the outer periphery of the first groove, and an adjustable pressure stabilizing / throttling unit is provided on the exhaust pipe communicating with the air chamber so that the air chamber always maintains a positive pressure relative to the outside during operation.

7. The clamp according to claim 1, characterized in that, Both the second and fourth air ports are connected to a gas source for supplying protective gas, and both the first and third air ports are used to introduce protective gas into the air cavity.

8. The clamp according to claim 7, characterized in that: An annular guide groove and / or pressure relief hole array are provided at the bottom of the second groove corresponding to the outer edge of the first region. The guide groove or pressure relief hole array is connected to the outside of the fixture to form a directional pressure relief overflow path.

9. The clamp according to claim 8, characterized in that, The first flow channel and the second flow channel are respectively provided with adjustable flow rate throttling / pressure stabilizing units. The throttling / pressure stabilizing units are configured to make the total air supply flow rate of the first air port and the third air port greater than the flow rate overflowing through the pressure relief overflow path under steady state, so that the static pressure in the air chamber is higher than the external air pressure.

10. The clamp according to claim 9, characterized in that, The fixture further includes a pressure sensing element and a valve control unit; the sensing end of the pressure sensing element is connected to the air chamber, and the signal output end of the pressure sensing element is electrically connected to the valve control unit; the valve control unit is electrically connected to a throttling / pressure stabilizing unit disposed on the first flow channel and / or the second flow channel; the valve control unit is configured to adjust the opening of the throttling / pressure stabilizing unit according to the static pressure of the air chamber detected by the pressure sensing element, so that the total flow rate entering the air chamber under steady state is greater than the total flow rate overflowing through the pressure relief overflow path, and to maintain the static pressure in the air chamber within a set range higher than the external air pressure.

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