A composite heat flow drill screw

Abstract

The invention discloses a composite hot-fluid drill screw, comprising a head, a rod threaded section and a tip; the head is used to connect with an external tool; the rod threaded section is used to self-drill a plate; the tip is used to penetrate the plate; the rod threaded section and the tip are made of different metal materials, and the ends of the two are connected and fixed by welding. By making the rod threaded section and the tip with two different materials, different plates can be handled and different usage scenarios can be met, and costs can be saved at the same time. This design enables the screw to perform well under various complex conditions, improves its applicability and reliability, and has significant economic and social benefits.

Description

Technical Field

[0001] The invention belongs to the technical field of thermal flow drill screws, in particular to a composite thermal flow drill screw. Background Art

[0002] Flow drill screws can complete the connection operation of dissimilar materials on a single side, and the holes formed on site can maintain sealing after connecting multiple parts; the hot melt self-tapping process eliminates the need to pre-drill holes, pre-set nuts or threads on the parts, simplifying the manufacturing process and reducing costs. Based on the above advantages, flow drill screws and hot melt self-tapping processes are widely used in products such as steel-aluminum hybrid bodies and battery pack trays;

[0003] The composite heat flow drill screw transmits heat to the plate to be connected through high-speed rotation, causing friction heat to produce plastic deformation, and then self-drilling and screwing. Figure 1 As shown, at the beginning of the tightening process, the hot-drill screw is placed on the surface of the plate (usually an aluminum plate or a thin steel plate), and the installation tool outputs a high speed and applies pressure to the hot-drill screw①, so that the tip of the high-speed rotating screw applies downward pressure to the surface of the workpiece, and at the same time generates extremely high friction heat to melt the plate②, and then the top of the screw penetrates the material to form a perforation, and continues to rotate to expand the perforation③, when the threaded section of the screw contacts the plate, the screw begins to tap the thread④⑤, and after the thread is formed, the screw is tightened according to the preset torque until the fastening connection is completed⑥;

[0004] In practical applications, for installation plates of different materials, such as high-strength plates, aluminum plates, etc., metal materials with stronger wear resistance are required to penetrate the plates. However, it is difficult to form threads on metal materials with strong wear resistance, and the cost is very high. In addition, existing screws cannot be customized, which means they cannot meet most usage scenarios. Summary of the invention

[0005] The object of the present invention is to provide a composite hot flow drill screw to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A composite hot-flow drill screw comprises a head, a shank threaded section and a tip;

[0008] The head is used to connect with an external tool;

[0009] The threaded section of the rod is used for self-tapping of the plate;

[0010] The pointed end is used to penetrate the plate;

[0011] The rod thread section and the tip are made of different metal materials, and the ends of the two are connected and fixed by welding.

[0012] Beneficial effects of the present invention:

[0013] The present invention makes the threaded section and the tip of the rod part using two different materials, which can cope with different plates and meet different usage scenarios, while saving costs. This design enables the screw to perform well under various complex conditions, improves its applicability and reliability, and has significant economic and social benefits.

[0014] According to a further technical solution, the end of the tip portion and the end of the threaded section of the rod portion are both provided with mutually matching concave and convex structures.

[0015] According to a further technical solution, the end of the tip portion and the end of the threaded section of the rod portion are both plane.

[0016] According to a further technical solution, the tip portion is made of tungsten steel alloy.

[0017] According to a further technical solution, the threaded section of the rod is made of corrosion-resistant steel.

[0018] According to a further technical solution, a plurality of concave points are arranged on the outer periphery of the lower end portion of the tip portion.

[0019] According to a further technical solution, a through hole is provided at the center axis of the threaded section of the rod, one end of the through hole extends to the end face of the tip portion, and the other end extends to the head portion to communicate with the outside.

[0020] A method of use, which is used for fixing ultra-high strength steel plates, includes the above-mentioned composite hot flow drill screw, and the specific steps are as follows:

[0021] In the first step, the head of the screw is clamped by a tool, and the other end of the screw contacts the ultra-high strength steel plate and keeps it vertical to the ultra-high strength steel plate. At the same time, a pressure rod is provided in the tool and penetrates into the through hole, and the end of the pressure rod contacts the end surface of the tip;

[0022] In the second step, the tool applies pressure to the screw, and the head and the end surface of the tip of the screw are simultaneously subjected to pressure, and the pressure is concentrated at the contact point between the tip and the ultra-high-strength steel plate, so that a groove fixing point is formed on the ultra-high-strength steel plate;

[0023] The third step is to use tools to make the screw rotate at high speed and continuously apply pressure to the ultra-high-strength steel plate, so that huge friction is generated between the ultra-high-strength steel plate and the tip. The tip is made of tungsten steel alloy, so that the tip can withstand 900-1000°C. During this process, the ultra-high-strength steel plate is in a hot red and soft state, so that the tip penetrates the ultra-high-strength steel plate. At the same time, when the ultra-high-strength steel plate is in a hot red state, the threaded section of the rod contacts it, making it easier for the ultra-high-strength steel plate to form threads.

[0024] Beneficial effects of the present invention:

[0025] When the present invention applies pressure to the screw, the pressure rod penetrates into the through hole of the threaded section of the rod and abuts against the end face of the tip, so that the force directions of the two remain consistent and the two are not easily deformed. In addition, the applied force can be directly transmitted to the tip, so that the ultra-high strength steel plate forms a groove fixing point.

[0026] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 : Schematic diagram of the use process of the present invention.

[0028] Figure 2 : The overall structure of the present invention Figure 1 .

[0029] Figure 3 : Schematic diagram of the threaded section and tip portion of the rod of the present invention.

[0030] Figure 4 : The overall structure of the present invention Figure 2 . DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0032] Please refer to Figure 1-4 ;

[0033] The hot-drill screw of the present invention adopts a composite structure, which is intended to adapt to different plates and use environments, and can effectively save costs. Specifically, it includes a head 1, a rod threaded section 2 and a tip 3; wherein the head 1 is used to connect with an external tool, the rod threaded section 2 is used to self-drill the plate, and the tip 3 is used to penetrate the plate. The rod threaded section 2 and the tip 3 are made of different metal materials, and the ends of the two are connected and fixed by welding;

[0034] Assuming that the hot-fluid drill screw is used in an ultra-high-strength steel plate, when in use, the tool is connected to the head 1, and a high output speed and pressure are applied, so that the high-speed rotating screw tip 3 applies downward pressure to the workpiece surface. In this process, extremely high friction heat will be generated between the tip 3 and the ultra-high-strength steel plate. The ultra-high-strength steel plate can withstand extremely high temperatures, while ordinary hot-fluid drill screws are usually made of stainless steel or alloy. Before they pass through the ultra-high-strength steel plate, their tip 3 will melt and deform due to the high temperature and cannot continue. Therefore, it is thought that a higher-strength metal is used to make hot-fluid drill screws, among which tungsten steel is preferably used, which has a high hardness of 82.0 to 93.6. HRA, equivalent to 69-81HRC, good red hardness, up to 900-1000℃, no deformation when maintaining 60HRC, and good wear resistance, but because of these characteristics, it is very difficult to process the thread and the cost is very high. Therefore, in this embodiment, the tip 3 is made of tungsten steel, and the rod thread section 2 is made of stainless steel. The whole screw is welded together. The characteristics of tungsten steel can be used without deformation at extremely high temperatures and can pass through ultra-high strength steel plates. At the perforation, the ultra-high strength steel plates will produce extremely high temperatures and soften. At this time, the rod thread section 2 enters the through hole 21 to easily achieve self-tapping and achieve connection and fixation;

[0035] To expand further, a huge friction force needs to be generated to penetrate the ultra-high-strength steel plate. The outer periphery of the traditional tip is relatively smooth, and it is difficult to generate a huge friction force, resulting in a very long time to penetrate the ultra-high-strength steel plate. In order to solve this problem, in this embodiment, a plurality of concave points 31 are provided on the outer periphery of the lower end part of the tip to increase the friction force between the tip and the ultra-high-strength steel plate, so that it can generate high temperature more quickly, so as to penetrate the ultra-high-strength steel plate in a shorter time.

[0036] Assuming that it is used in a relatively harsh environment, the environment has a certain degree of corrosion. At this time, the more important parts are the head 1 and the rod threaded section 2, which are responsible for the subsequent screw removal, because these two parts need to be corrosion-resistant, and these two parts are preferably integrally formed and made of corrosion-resistant steel. In this embodiment, the tip 3 is not so important. It is mainly used to penetrate the plate. After the rod threaded section 2 is fixed to the plate, the task is completed. After a period of subsequent use, it will not affect the fixing effect of the rivet even if it is corroded. Therefore, in this embodiment, the tip 3 is made of ordinary stainless steel. Of course, the plate used in this embodiment is a plate of ordinary thickness and material, and only a corrosion-resistant layer is coated on its surface, etc. The tip 3 made of stainless steel can penetrate it; the cost of corrosion-resistant steel is higher than that of ordinary steel, and the use of a segmented structure can effectively save costs;

[0037] In the present invention, the rod threaded section 2 and the tip portion 3 are made of two different materials, which can cope with different plates and meet different usage scenarios, while saving costs. This design enables the screw to perform well under various complex conditions, improves its applicability and reliability, and has significant economic and social benefits.

[0038] There are many welding methods in the present invention, among which friction welding and eddy current welding are more commonly used. In this embodiment, the end of the tip portion 3 and the end of the rod threaded section 2 are provided with mutually matching concave-convex structures, and the ends of the two parts can be aligned through the concave-convex structure. Then, the coil is energized to generate eddy currents at the connection between the two to form a large amount of heat melting to achieve a fixed connection, and then grinding can be performed.

[0039] Alternatively, the end of the tip portion 3 and the end of the rod thread segment 2 are both flat, the tip portion 3 and the rod thread segment 2 are clamped by fixtures respectively, the two are coaxially aligned, and then the ends of the two are in contact with each other, and the two fixtures are started to rotate in opposite directions, so that the contact point of the tip portion 3 and the rod thread segment 2 is rubbed at high speed to generate a large amount of heat, and finally melted and fixed, and then polished;

[0040] The above two welding methods can fully fix the rod thread section 2 and the tip portion 3 together to avoid breakage during high-speed rotation and friction.

[0041] It is necessary to apply a large pressure to the screw during use. Since the screw is made of two different metals, its stress structure is destroyed, and the pressure it can withstand is less than that of an integrally formed screw. Therefore, after a certain pressure is applied to it, it will bend. In order to solve this problem, in the embodiment of the utility model, a through hole 21 is provided at the center axis position of the threaded section of the rod. One end of the through hole 21 extends to the end face of the tip, and the other end extends to the head to communicate with the outside. The through hole 21 can be first formed at the threaded section of the rod, or it can be formed by turning the hole after the screw is formed.

[0042] In one embodiment, the tip is made of tungsten steel, which is extremely difficult to process and it is difficult to ensure that it is aligned with the through hole 21 of the rod threaded section after processing. Therefore, only the through hole 21 is formed at the rod threaded section to compensate for the lack of stress.

[0043] When in use, the head of the screw is clamped by a tool, and the other end of the screw is in contact with the ultra-high strength steel plate and kept vertically therewith. At the same time, a pressing rod is provided in the tool and passes through the through hole 21, and the end of the pressing rod is in contact with the end face of the tip and in contact at the center of the end face of the tip. The threaded section of the rod is subjected to the same force as the tip, and the threaded section of the rod will not bend relative to the tip.

[0044] The present invention also discloses a method of use, which is used for fixing an ultra-high strength steel plate, comprising the above-mentioned composite hot flow drill screw, and the specific steps are as follows:

[0045] In the first step, the head of the screw is clamped by a tool, and the other end of the screw contacts the ultra-high strength steel plate and keeps it vertical to the ultra-high strength steel plate. At the same time, a pressing rod is provided in the tool and penetrates into the through hole 21, and the end of the pressing rod contacts the end surface of the tip;

[0046] In the second step, the tool applies pressure to the screw, and the head and the end surface of the tip of the screw are simultaneously subjected to pressure, and the pressure is concentrated at the contact point between the tip and the ultra-high-strength steel plate, so that a groove fixing point is formed on the ultra-high-strength steel plate;

[0047] The third step is to use tools to make the screw rotate at high speed and continuously apply pressure to the ultra-high-strength steel plate, so that huge friction is generated between the ultra-high-strength steel plate and the tip. The tip is made of tungsten steel alloy, so that the tip can withstand 900-1000°C. During this process, the ultra-high-strength steel plate is in a hot red and soft state, so that the tip penetrates the ultra-high-strength steel plate. At the same time, when the ultra-high-strength steel plate is in a hot red state, the threaded section of the rod contacts it, making it easier for the ultra-high-strength steel plate to form threads.

[0048] Based on the above-mentioned usage method, when pressure is applied to the screw, since the pressure rod penetrates into the through hole of the threaded section of the rod and abuts against the end face of the tip, the force directions of the two remain consistent and the two are not easily deformed. In addition, the applied force can be directly transmitted to the tip, so that the ultra-high-strength steel plate forms a groove fixing point.

[0049] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0050] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementations that can be understood by those skilled in the art.

Claims

1. A composite hot-flow drill screw, comprising a head (1), a shank threaded section (2) and a tip (3), characterized in that: The head (1) is used to connect with an external tool; The rod threaded section (2) is used for self-tapping of the plate, and a through hole (21) is provided at the center axis of the rod threaded section (2), one end of the through hole (21) extends to the end surface of the tip portion (3) close to the head, and the other end extends to the head (1) to communicate with the outside world; The tip (3) is used to penetrate the plate, and the tip (3) is made of tungsten steel alloy. The rod thread section (2) and the tip portion (3) are made of different metal materials, and the ends of the two are connected and fixed by welding; The composite hot flow drill screw is used to fix the ultra-high strength steel plate. The specific steps are as follows: In the first step, the head (1) of the screw is clamped by a tool, and the other end of the screw contacts the ultra-high strength steel plate and is kept vertically above the ultra-high strength steel plate. At the same time, a pressing rod is provided in the tool and penetrates into the through hole (21), and the end of the pressing rod contacts the end surface of the tip portion (3) close to one end of the head, the rod thread section and the tip portion are subjected to the same force, and the rod thread section will not bend relative to the tip portion; In the second step, the tool applies pressure to the screw, and the end surface where the head and tip of the screw contact the ultra-high-strength steel plate are simultaneously subjected to pressure, and the pressure is concentrated at the contact point between the tip and the ultra-high-strength steel plate, so that a groove fixing point is formed on the ultra-high-strength steel plate; The third step is to use a tool to rotate the screw at a high speed and continuously apply pressure to the ultra-high strength steel plate, so that a huge friction force is generated between the ultra-high strength steel plate and the tip. The tip is made of tungsten steel alloy material, so that the tip can withstand 900-1000°C. During this process, the ultra-high strength steel plate is in a hot red and soft state, so that the tip (3) penetrates the ultra-high strength steel plate. At the same time, when the ultra-high strength steel plate is in a hot red state, the rod thread section (2) contacts it, making it easier for the ultra-high strength steel plate to form threads.

2. A composite hot flow drill screw according to claim 1, characterized in that: The end of the tip portion (3) and the end of the rod threaded section (2) are both provided with mutually matching concave and convex structures.

3. The composite hot flow drill screw according to claim 1, characterized in that: The end of the tip portion (3) and the end of the rod threaded section (2) are both flat.

4. The composite hot flow drill screw according to claim 1, characterized in that: The rod thread section (2) is made of corrosion-resistant steel.

5. The composite hot flow drill screw according to claim 1, characterized in that: A plurality of concave points (31) are arranged on the outer periphery of the lower end portion of the tip portion (3).

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