FDS screw, screw machining method and plate connecting method

Abstract

The invention relates to an FDS screw, a screw machining method and a plate connecting method. The FDS screw comprises a head part and a rod body arranged below the head part, a groove is formed in the side, close to the rod body, of the head part, and the groove is annularly formed along the rod body; the FDS screw further comprises a housing which can be distorted and deformed under stress. And one end of the housing is sleeved on the rod body, and the other end of the housing extends into the groove. According to the FDS screw, chippings generated during tapping of the FDS screw can be timely and smoothly discharged out of the joint position under the combined action of lateral component force generated when the chippings are extruded by the curved surface and centrifugal force of the housing during high-speed rotation, the chippings are prevented from being accumulated below the head, and the service life of the FDS screw is prolonged. And meanwhile, a metal lining, a housing and a part of scraps which are not discharged completely generated during punching of the plate can be plugged into the groove, so that the head of the FDS screw is completely attached to the plate, the contact between the joint of the head of the FDS screw and the air is isolated, and the electrochemical reaction at the joint of the FDS screw is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of screws, and in particular to an FDS screw, a screw processing method and a plate connecting method. Background Art

[0002] In recent years, with the gradual rise of new energy vehicles, "lightweight" has become a development trend. High-strength steel, aluminum, and magnesium alloy materials are widely used in white bodies. For the connection of dissimilar materials, FDS screws (also known as flow drill screws, hot melt self-tapping screws) can replace traditional welding to achieve better connection effects. FDS screws have many advantages for the connection between abnormal materials, but there are also some disadvantages. For example, the front and back sides of the plates connected by FDS screws have large protrusions, and the debris generated on the front side will accumulate under the head of the FDS screw, resulting in a gap between the head of the FDS screw and the connected plate, so that the connection part is in contact with the air, resulting in a decrease in the corrosion resistance of the joint. In some FDS screw designs, a flange head is used, and a chip groove is provided under the flange head. This chip groove design allows part of the chips generated by the FDS screw tapping the plate to be discharged, and part of it will accumulate in the groove. At this time, there is a possibility that the chips cannot fill the chip groove, and the chips themselves have a large contact area with the air, and there is still a possibility of electrochemical corrosion, which affects the strength and life of the FDS screw connection joint. Summary of the invention

[0003] Based on this, it is necessary to provide an FDS screw, a screw processing method and a plate connection method to address the problem that there is a gap between the head of the existing FDS screw and the connected plate, which causes the connecting part to come into contact with the air and leads to a decrease in the corrosion resistance of the joint.

[0004] An FDS screw comprises a head and a rod body arranged below the head, a groove is provided on a side of the head close to the rod body, and the groove is arranged in an annular manner along the rod body;

[0005] The FDS screw also includes a cover shell that can be twisted and deformed under force; one end of the cover shell is sleeved on the rod body, and the other end extends into the groove; the internal space of the cover shell and the groove together form a cavity, and the outer surface of the cover shell has a curved surface protruding from the cavity; the cover shell is used to discharge the debris generated when the screw is tapped, using the lateral force generated by the curved surface squeezing the debris and the centrifugal force when the cover shell rotates to discharge the debris out of the joint; when the cover shell is deformed under force, the cover shell is compressed into the groove.

[0006] As a preferred example, one end of the cover shell abuts against the inner wall of the groove; the inner wall of the groove is an arc-shaped surface and is used to guide the cover shell to enter the groove when the cover shell is deformed.

[0007] As a preferred example, the cover shell is in the shape of a pot cover as a whole; the open end of the cover shell is connected to the groove.

[0008] As a preferred example, the cover shell and the rod body are connected by spot welding, and there are at least three welding spots between the two.

[0009] As a preferred example, the end of the head away from the rod body is arranged as a smooth portion, and a hexagonal recessed groove for transmitting power is provided in the middle of the smooth portion.

[0010] As a preferred example, the end of the rod body close to the head is a smooth portion and is connected to the cover shell; the middle position of the rod body is a threaded portion; and the end of the rod body away from the head is a cone portion.

[0011] A method for processing an FDS screw, which processes the FDS screw as described above; the method for processing the FDS screw comprises the following steps:

[0012] A groove is machined on an ordinary FDS screw; a cover shell that has been machined in advance is placed on the rod body, and one end of the cover shell extends into the groove; and the cover shell and the rod body are welded using a spot welding process.

[0013] As a preferred example, during spot welding, there are at least three welding points for connection between the cover shell and the rod body, and the multiple welding points are evenly distributed along the ring of the rod body.

[0014] A method for connecting plates, using the FDS screws as described above; the method for connecting plates comprises the following steps:

[0015] Put the plates together, and use the rotary feed device to drive the FDS screw to rotate and move toward the plate until the cone of the FDS screw passes through all the plates;

[0016] The rotation speed of the rotary feed device is reduced, and the FDS screw continues to move downward, and the threaded portion of the FDS screw taps the thread in the perforation of the plate; while tapping, the debris generated by the thread contacts the cover; the lateral force generated by the cover squeezing the debris, and the centrifugal force of the cover during high-speed rotation, work together to enable the debris to be discharged from the joint position in a timely and smooth manner;

[0017] The rotary feed device maintains a uniform rotation speed. During this process, the metal bushing squeezes the cover shell, causing the cover shell to deform into the groove, and eventually the protruding metal bushing, cover shell and some debris that have not been discharged are all stuffed into the groove until the FDS screw reaches the set tightening torque on the plate.

[0018] As a preferred example, when the plates are attached to each other, pressure is applied to the plates through a pressure ring; the FDS screws connect the plates inside the pressure ring.

[0019] The beneficial effect of the present invention is that: through the design of the groove and the cover shell, the present invention enables the debris generated by the FDS screw during tapping to utilize the lateral force generated when the curved surface squeezes the debris, and the centrifugal force of the cover shell during high-speed rotation. The two work together to enable the debris to be discharged from the joint position in a timely and smooth manner, preventing the debris from accumulating under the head. At the same time, the metal bushing, cover shell and some debris that are not discharged cleanly when punching the plate will be stuffed into the groove, so that the FDS screw head and the plate are completely fitted, isolating the contact between the FDS screw head joint and the air, reducing the electrochemical reaction at the FDS screw joint, and better adapting to the hydrochloric acid corrosion environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the three-dimensional structure of the FDS screw in the embodiment;

[0021] Figure 2 A schematic cross-sectional view of an FDS screw in an embodiment;

[0022] Figure 3 It is a structural schematic diagram of the cover shell in the embodiment;

[0023] Figure 4 Schematic diagram of the relationship between the FDS screw and the plate in the hole forming stage in the embodiment;

[0024] Figure 5 Schematic diagram of the relationship when the FDS screws complete the plate connection in the embodiment.

[0025] In the figure: head 1, cover shell 2, smooth part 3, threaded part 4, cone part 5, plate 6, metal bushing 7. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] It should be noted that when a component is referred to as being "mounted on" another component, it may be directly on the other component or there may be a central component. When a component is considered to be "set on" another component, it may be directly set on the other component or there may be a central component at the same time. When a component is considered to be "fixed to" another component, it may be directly fixed on the other component or there may be a central component at the same time.

[0028] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "or / and" used herein includes any and all combinations of one or more of the related listed items.

[0030] Please refer to Figure 1 and Figure 2 In this embodiment, an FDS screw is proposed, which includes a head 1, a rod body and a cover shell 2 arranged below the head 1. Among them, a smooth portion is set at one end of the head 1 away from the rod body, and a hexagonal countersink groove for transmitting power is opened in the middle position of the smooth portion. Some existing FDS screws have a mushroom head with an arc-shaped head 1. The head 1 of the FDS screw is not stable enough when the cutter head is positioned, and because of the arc-shaped top design, the depth at the edge below the head 1 is limited. In order not to affect the strength of the screw, a chip groove cannot be opened at the edge of the head 1, resulting in the need for the traditional mushroom head FDS screw to pre-open a hole for the plate 6 close to the head 1 during assembly. The FDS screw head 1 in this solution is designed with a platform-shaped top design, which, in conjunction with the hexagonal countersink groove design, can conveniently and stably position the cutter head and reduce the pre-opening process. On the other hand, a groove is opened at one end of the head 1 close to the rod body. The groove is arranged in a ring along the rod body. On the one hand, the groove can accommodate some debris, and can also accommodate part of the metal bushing 7 generated by the plate 6 when drilling.

[0031] The rod body is also different from a conventional screw. The end of the rod body close to the head 1 is a smooth portion 3, which is used to connect with the housing 2. The middle of the rod body is a threaded portion 4, which is used to tap the plate 6 and screw with the plate 6. The end of the rod body away from the head 1 is a cone 5, which is used to apply high downward pressure to the surface of the plate 6 under high-speed rotation, while generating extremely high friction heat to melt the metal, and then the cone 5 penetrates the plate 6 to finally form a perforation.

[0032] One of the key points in this solution is the design of the housing 2. The housing 2 is a thin shell structure and can be twisted and deformed when subjected to a large external force. Figure 3As shown, the cover shell 2 as a whole can be set to be in the shape of a pot cover. The cover shell 2 is sleeved on the rod body as a whole, and one end of the opening of the cover shell 2 extends to the inside of the groove and abuts against the inner wall of the groove. Matching this, the inner wall of the groove abutting against the cover shell 2 can be set to an arc surface, and the arc design guides the cover shell 2 to be able to twist and compress into the groove when it is compressed and deformed. The other end of the cover shell 2 is sleeved on the rod body and fixed to the rod body. It should be mentioned that the cover shell 2 needs to be separated from the rod body and compressed into the groove in the end, so the connection between the cover shell 2 and the rod body can be spot welded. The cover shell 2 and the rod body are connected by multiple welding points, which ensures a certain connection strength while allowing the cover shell 2 to be separated from the rod body under force. The design of the above-mentioned cover shell 2 makes the internal space of the cover shell 2 and the groove form a cavity together, and at this time the outer surface of the cover shell 2 has a curved surface protruding from the cavity. As shown Figure 4 As shown, the curved surface relative to the feed direction of the FDS screw enables the chips generated by the FDS screw during tapping to utilize the lateral force generated when the curved surface squeezes the chips, as well as the centrifugal force of the cover 2 during high-speed rotation. The two work together to enable the chips to be discharged from the joint position in a timely and smooth manner, thereby preventing the chips from accumulating under the head 1. On the other hand, when the FDS screw penetrates the plate 6, most of the hot-melted plate 6 will form a metal bushing 7 with a thickness of 1 to 3 times that of the plate 6 above and below the drill hole. Part of the metal bushing 7 will protrude above the plate 6. The partially protruding metal bushing 7 will also affect the gap between the FDS screw head 1 and the plate 6. In this embodiment, Figure 5 As shown, as the FDS screw is continuously tapped, the protruding metal bushing 7 squeezes the cover 2, causing the cover 2 to deform into the groove, and eventually the protruding metal bushing 7, the cover 2, and some debris that have not been completely discharged are all stuffed into the groove. In this way, no obstacles will be generated between the head 1 and the plate 6, and no gap will be generated, so that the FDS screw head 1 and the plate 6 are completely fitted, isolating the FDS screw head 1 from contact with the air at the joint. In addition, the cover 2, metal bushing 7, etc. squeezed into the groove will also generate an upward pre-tightening force on the head 1, thereby helping the FDS screw to be connected to the plate 6 more firmly and not easily loosened.

[0033] In other embodiments, other connection methods may be used between the cover 2 and the rod body, such as integral welding or adhesive bonding. Even if the connection strength of some connection methods is too strong, so that the cover 2 is not separated from the rod body, the cover 2 is still deformed by force, and part of it extends into the groove, and part of it is directly squeezed into the gap between the rod body and the metal bushing 7, which serves to isolate the screw joint from contact with the air.

[0034] In another embodiment, a method for processing an FDS screw is also provided, which processes the above-mentioned FDS screw. The method for processing the FDS screw comprises the following steps:

[0035] A groove is machined on an ordinary FDS screw. The pre-machined cover 2 is placed on the rod body, and one end of the cover 2 extends into the groove. The cover 2 and the rod body are welded using a spot welding process. During spot welding, there are at least three welding points for connection between the cover 2 and the rod body, and the multiple welding points are evenly distributed along the ring of the rod body.

[0036] In another embodiment, a method for connecting plates 6 is also proposed, which uses the FDS screws described above to connect the plates 6. Taking the connection of two plates 6 as an example, the method for connecting plates 6 includes the following steps:

[0037] (1) Positioning stage: The hexagonal cutter head in the middle of the rotating feed device is positioned and engaged with the hexagonal countersunk groove of the FDS screw head 1. The force of the screw rotation is transmitted from the cutter head to the nail head through the hexagonal countersunk groove, thereby driving the entire nail body, and using the pressure ring to press the connected plate 6 by pressing the pressure ring downward, so that the plate 6 will not jump or deviate during the penetration stage.

[0038] (2) Penetration stage: The FDS screw rotates at high speed and rubs the plate 6 to generate high temperature, which reaches 500-600℃ (the screw has a special coating that is not affected by high temperature), softening the metal and punching holes. The whole stage lasts until the FDS screw passes through the lower plate.

[0039] (3) Hole forming stage: In the thermoplastic deformation stage, the rotation speed is reduced, the FDS screw moves downward, and the contact area between the cone 5 of the FDS screw and the plate 6 increases. Under the axial and rotational forces, the molten metal material of the plate 6 flows thermoplastically in the axial and radial directions to form a ring neck and a metal bushing 7, forming a through hole larger than the thickness of the plate 6, preparing for the next stage.

[0040] (4) Thread forming stage: The rotation speed of the FDS screw is further reduced, and threads are tapped on the ring neck and the metal bushing 7. Part of the generated debris falls off from the lower plate, and part is discharged from the joint in a timely and smooth manner through the cover 2 design of the FDS screw head 1. While preventing waste accumulation, it better isolates the inside of the joint from contact with the air, reduces the electrochemical reaction inside the joint, and makes the joint more adaptable to the hydrochloric acid corrosion environment.

[0041] (5) Screwing-in phase: The FDS screw maintains a uniform rotation speed.

[0042] (6) After the FDS screw reaches the set tightening torque, the protruding metal bushing 7, the cover 2 and some debris that have not been discharged are all stuffed into the groove, so that there is no gap between the head 1 and the plate 6, which isolates the joint from the air to a greater extent, prevents the occurrence of electrochemical corrosion, and increases the strength of the joint. Then the connection of the plate 6 is completed.

[0043] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0044] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. An FDS screw, comprising a head (1) and a rod body arranged below the head (1), characterized in that: A groove is provided on a side of the head (1) close to the rod body, and the groove is arranged in a ring shape along the rod body; The FDS screw further comprises a cover shell (2) which can be deformed by twisting under force; one end of the cover shell (2) is sleeved on the rod body, and the other end extends into the groove; the internal space of the cover shell (2) and the groove together form a cavity, and the outer surface of the cover shell (2) has a curved surface protruding from the cavity; the cover shell (2) is used to discharge debris generated when the screw is tapped out of the joint by using the lateral force generated by squeezing the debris on the curved surface and the centrifugal force when the cover shell (2) rotates; when the cover shell (2) is deformed by force, the cover shell (2) is compressed into the groove.

2. The FDS screw according to claim 1, characterized in that: One end of the cover shell (2) abuts against the inner wall of the groove; the inner wall of the groove is an arc-shaped surface and is used to guide the cover shell (2) into the groove when the cover shell (2) is deformed.

3. The FDS screw according to claim 1, characterized in that: The cover shell (2) is in the shape of a pot cover as a whole; the open end of the cover shell (2) is connected to the groove.

4. The FDS screw according to claim 1, characterized in that: The cover shell (2) and the rod body are connected by spot welding, and there are at least three welding points between the two.

5. The FDS screw according to claim 1, characterized in that: The end of the head (1) away from the rod body is arranged as a smooth portion, and a hexagonal recessed groove for transmitting power is provided in the middle of the smooth portion.

6. The FDS screw according to claim 1, characterized in that: The end of the rod body close to the head (1) is a smooth portion (3) connected to the cover shell (2); the middle position of the rod body is a threaded portion (4); and the end of the rod body away from the head (1) is a cone portion (5).

7. A method for processing an FDS screw, characterized in that: The FDS screw according to any one of claims 1 to 6 is processed; the processing method of the FDS screw The following steps are involved: A groove is machined on an ordinary FDS screw; a cover shell (2) that has been machined in advance is sleeved on the rod body, and one end of the cover shell (2) extends into the groove; and the cover shell (2) and the rod body are welded using a spot welding process.

8. The method for processing FDS screws according to claim 7, characterized in that: During spot welding, there are at least three welding points for connection between the cover shell (2) and the rod body, and the multiple welding points are evenly distributed along the ring shape of the rod body.

9. A method for connecting plates, characterized in that: The FDS screw according to any one of claims 1 to 6 is used; the plate connection method comprises the following steps: The plates are placed against each other, and the FDS screw is driven by the rotary feed device to rotate and move toward the plate until the cone (5) of the FDS screw passes through all the plates; The rotation speed of the rotary feed device is reduced, and the FDS screw continues to move downward, and the threaded portion (4) of the FDS screw taps a thread in the perforation of the plate; while tapping the thread, the debris generated by the thread contacts the cover (2); the lateral force generated when the cover (2) squeezes the debris, and the centrifugal force of the cover (2) during high-speed rotation, both work together to enable the debris to be discharged from the joint position in a timely and smooth manner; The rotary feed device maintains a uniform rotation speed. During this process, the metal bushing (7) squeezes the cover shell (2), causing the cover shell (2) to deform into the groove, and finally the protruding metal bushing (7), the cover shell (2) and some debris that have not been discharged are all stuffed into the groove until the FDS screw reaches the set tightening torque on the plate.

10. The method for connecting plates according to claim 9, characterized in that: When the plates are attached to each other, pressure is applied to the plates through the pressure ring; the FDS screw connects the plates inside the pressure ring.

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