Self-piercing rivet and connection structure
By designing a sealing thread section and a forming thread section on the self-tapping screw and setting a sealing layer on the outer surface, the problem of insufficient sealing and fastening of self-tapping screws during connection is solved, achieving efficient sealing and reliable fastening effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- ARNOLD FASTENERS (SHENYANG) CO LTD
- Filing Date
- 2025-07-10
- Publication Date
- 2026-07-21
AI Technical Summary
Existing self-tapping screws cannot simultaneously guarantee reliable fastening and sealing of the connection interface when connecting components.
Design a self-tapping screw whose screw includes a sealing thread section and a forming thread section. The external thread cross-sectional area and major diameter of the sealing thread section are larger than those of the forming thread section, and a sealing layer is provided on the outer surface. When screwed in, the sealing thread section is pressed against the inner groove wall, and the sealing performance is enhanced by the combination of the annular groove and the sealing layer.
Without significantly increasing the installation torque, self-tapping screws achieve good sealing and threaded connection performance, simplify the fastening process, and improve the sealing of the connection interface.
Smart Images
Figure CN224533214U_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to the field of fastener technology, and more specifically to a self-tapping screw and connection structure. Background Technology
[0002] Self-tapping screws are widely used to achieve detachable connections between components. When screwed into the components to be connected, the self-tapping screw creates an internal thread while simultaneously securing its own external thread to that internal thread. In addition to ensuring a reliable fastening effect, such self-tapping screws must also meet the sealing requirements of the connection interface.
[0003] It should be noted that the content described herein is only to provide background information in relation to this disclosure and does not necessarily belong to the prior art. Utility Model Content
[0004] Depending on the specific aspects, the purpose of this disclosure is to provide an improved self-tapping screw and a connection structure including such a self-tapping screw, wherein the self-tapping screw can achieve a fastening connection with better sealing performance.
[0005] In addition, this disclosure is also intended to address or mitigate other technical problems existing in the prior art.
[0006] According to a first aspect of this disclosure, a self-tapping screw is provided, comprising a head and a screw extending from the head along an axial direction, the screw including a sealing thread section and a forming thread section, wherein the sealing thread section is closer to the head than the forming thread section, a sealing layer is provided on the outer surface of the sealing thread section, wherein, in a cross-section along the axial direction, the cross-sectional area of the external thread of the sealing thread section is greater than the cross-sectional area of the external thread of the forming thread section, and wherein the sealing layer of the sealing thread section can be pressed against the wall of an inner slot formed by the forming thread section.
[0007] According to some embodiments of this disclosure, optionally, the cross-sectional area of the external thread of the sealing thread section is 0.05 mm larger than the cross-sectional area of the external thread of the forming thread section. 2 up to 0.5mm 2 ;
[0008] And / or, the major diameter of the external thread of the sealing thread section is 0.05 mm to 0.5 mm larger than the major diameter of the external thread of the forming thread section.
[0009] According to some embodiments of this disclosure, optionally, the thickness of the sealing layer at the sealing thread section is 0.04 mm to 1 mm.
[0010] According to some embodiments of this disclosure, optionally, an annular groove is provided on the bottom surface of the head facing the screw, the annular groove surrounding the screw externally and one end connected to the screw.
[0011] According to some embodiments of this disclosure, optionally, a sealing layer with a thickness of 0.4 mm to 1.25 mm is provided on the inner wall of the annular groove.
[0012] According to some embodiments of this disclosure, optionally, a sealing layer with a thickness of 0.05 mm to 0.7 mm is provided on the portion of the bottom surface of the head surrounding the annular groove.
[0013] According to some embodiments of this disclosure, optionally, a tapered entry section is provided at the end of the screw away from the head, which gradually narrows in the direction away from the head.
[0014] According to some embodiments of this disclosure, optionally, a rod section is provided between the head and the sealing thread section, and the rod section is not threaded on its outer surface.
[0015] According to a second aspect of this disclosure, a connection structure is also proposed, comprising a first component, a second component, and the aforementioned self-tapping screw for connecting the first component and the second component, wherein an inner groove is formed in the first component and the second component by the shaped threaded section, and the sealing threaded section presses its sealing layer against the wall surface of the inner groove.
[0016] According to some embodiments of this disclosure, optionally, a boss is provided on the surface of one of the first component and the second component facing away from the other component, and the boss is passed through by the self-tapping screw in the connected state.
[0017] According to some implementations, self-tapping screws can improve the sealing of the connection interface while ensuring reliable connection strength. Attached Figure Description
[0018] Referring to the accompanying drawings, the above and other features of this disclosure will become apparent, wherein,
[0019] Figure 1 An embodiment of a connection structure according to the present disclosure is shown, which includes a self-tapping screw according to an embodiment of the present disclosure;
[0020] Figure 2 The enlarged view shows the external threads of a self-tapping screw according to another embodiment, respectively belonging to the sealing thread section and the forming thread section. Detailed Implementation
[0021] The present disclosure will now be described more fully with reference to the accompanying drawings, which illustrate exemplary embodiments thereof. However, the present disclosure may be implemented in various forms and should not be construed as being limited to the embodiments set forth herein. The foregoing embodiments are intended to make the disclosure herein complete and thorough, so as to more fully convey the scope of protection of the present disclosure to those skilled in the art.
[0022] In this specification, terms such as “comprising” and “including” indicate that, in addition to the units and steps that are directly and explicitly stated in the specification and claims, the technical solutions of this disclosure do not exclude the presence of other units and steps that are not directly or explicitly stated.
[0023] Unless otherwise specified, terms such as “first” and “second” do not indicate the order of units in terms of time, space, size, etc., but are merely used to distinguish between units.
[0024] refer to Figure 1 The diagram shows a cross-sectional view of a connection structure according to an embodiment of the present disclosure. The connection structure 1 includes a first component 11, a second component 12, and a self-tapping screw 100 for fastening the two components together, particularly for a detachable fastening connection. The first component 1 and the second component 2 are sheet metal; exemplarily, the sheet metal may be made of aluminum, steel, composite metal sheet metal, or may be made of plastic or other non-metallic sheet metal. It should be noted that the two components to be connected are not necessarily made of the same material.
[0025] from Figure 1 As can be seen, the self-tapping screw 100, such as a flow drill screw (FDS), generally includes a head 110 and a threaded rod 120 extending from the head along an axial direction, wherein the axial direction is parallel to the length direction of the self-tapping screw and passes through the center of the head; that is, this axial direction can also be referred to as the central axis and is shown by a dashed line in the figure. The threaded rod 120 is essentially a round rod, that is, it has a substantially circular cross-section perpendicular to the axial direction. Alternatively, the threaded rod may have a substantially triangular cross-section or other types of cross-section.
[0026] An external thread is provided on a portion of the outer surface of the screw 120, comprising a sealing thread section 121 (which is outlined in dashed lines in the drawings) and a forming thread section 122, wherein a sealing layer (not shown) is provided on the outer surface of the sealing thread section (i.e., on the surface of its external thread). Exemplarily, this sealing layer may be a sealant layer. When the self-tapping screw 100 is screwed in, the forming thread section 122, which is farther from the head 110, correspondingly taps an inner groove (i.e., an internal thread) in the first member 11 and the second member 12, and the external thread (i.e., the external thread) of the sealing thread section 122 then thread-fits into the inner groove. Here, by making the cross-sectional area of the external thread of the sealing thread section 121 larger than the cross-sectional area of the external thread of the forming thread section 122 (or, more specifically, larger than the cross-sectional area of the inner groove hole tapped by the external thread of the forming thread section 122), wherein the cross-sectional area is measured in the plane in the aforementioned axial direction, the sealing layer of the sealing thread section 121 can be squeezed into the inner groove hole and pressed against the wall of the inner groove hole, wherein the external thread of the sealing thread section performs secondary forming of the inner groove hole tapped by the forming thread section.
[0027] In this embodiment, since the cross-sectional area of the sealing thread section is larger than that of the forming thread section, the sealing layer can fill the entire inner groove and thereby achieve better sealing of the connection interface (between the self-tapping screw and the component to be connected).
[0028] Here, the cross-sectional area of the external thread in the sealing thread section refers to the external thread without a sealing layer, specifically the area of the entire external thread from its minor diameter to its major diameter. By analogy, the cross-sectional area of the external thread in the formed thread section is the area of the entire external thread from its minor diameter to its major diameter. See also... Figure 2 It schematically shows the external thread 1211 of the sealing thread section and the external thread 1221 of the forming thread section.
[0029] Specifically, in some embodiments, the cross-sectional area of the external thread of the sealing thread section 121 is 0.05 mm larger than the cross-sectional area of the external thread of the forming thread section. 2 up to 0.5mm 2 Specifically, the cross-sectional area of the external thread in the sealing thread section 121 is 0.13 mm larger than that of the external thread in the forming thread section. 2 Up to 0.25mm 2 This is to ensure that threaded connection performance and space for sealant are both achieved without significantly increasing installation torque.
[0030] In other embodiments, the difference in the cross-sectional area of the external threads of the sealing thread section 121 and the forming thread section 122 manifests as a difference in their major diameters. Specifically, refer to... Figure 2The major diameter of the external thread in the sealing thread section 121 is larger than that in the forming thread section 122, for example, by 0.05 mm to 0.5 mm. Specifically, the major diameter of the external thread in the sealing thread section 121 is 0.1 mm to 0.3 mm larger than that in the forming thread section 122, so as to balance threaded connection performance and space for sealant accommodation without significantly increasing installation torque.
[0031] In other embodiments, the difference in cross-sectional area between the external threads of the sealing thread section 121 and the forming thread section 122 manifests as a difference in their shapes, particularly a deviation in their thread angles. It can be configured such that, for the same major diameter, the external threads of the forming thread section 122 have a smaller thread angle than the sealing thread section 121. In this embodiment, it is also advantageous for the forming thread section to tap internal threads in the components to be connected.
[0032] It should be noted that the difference in cross-sectional area between the sealing thread section 121 and the forming thread section 122 can also be presented in other ways, and is not limited to the embodiments described above. For example, external threads can differ in both major diameter and thread angle.
[0033] In some embodiments, the thickness of the sealing layer of the sealing thread section 121 can be from 0.04 mm to 1 mm. Specifically, the thickness of the sealing layer of the sealing thread section 121 can be from 0.04 mm to 0.55 mm. Here, the thickness of the sealing layer can be determined based on the difference in cross-sectional area between the external threads of the sealing thread section 121 and the formed thread section 122, or the difference in cross-sectional area between the external threads of the sealing thread section 121 and the formed thread section 122 can be determined based on a predetermined sealing layer thickness.
[0034] from Figure 1 It can also be seen that at the end of the screw 120 away from the head 110, there is a tapping section 123 with or without external threads, which is generally tapered and gradually narrows away from the head. When screwing in the self-tapping screw, the tapping section can directly tap into the component to be connected without having to form a pre-drilled hole beforehand, thereby simplifying the fastening connection process.
[0035] Alternatively, external threads may be provided on at least a portion of the outer surface of the insertion section 123, for example only on the section furthest from the head 110 or on its entire outer surface, which may have a small tooth angle to facilitate insertion into the component to be connected. Furthermore, it is also possible that the insertion section 123 undergoes additional hardening treatment to facilitate insertion into the component to be connected.
[0036] In addition, a shank section (not shown in the drawings for clarity) is provided between the sealing thread section 121 and the head 110, and its outer surface is not threaded. Debris generated when the self-tapping screw 100 is screwed into the component to be connected can be collected between the shank section and the inner slot.
[0037] from Figure 1 It can also be seen that an annular groove 111 is provided on the bottom surface of the head 110 facing the screw 120, which surrounds the screw 120 on the outside and one end is connected to the screw 120 (that is, the side of the annular groove adjacent to the screw 120 transitions to the outer surface of the screw 120, specifically, it can transition to the outer surface of the aforementioned unthreaded rod section), thereby collecting the debris generated when the self-tapping screw 100 is screwed into the component to be connected.
[0038] To further ensure the sealing of the connection interface, a sealing layer is provided on the inner wall of the annular groove 111. This layer can be a sealant layer and its thickness can be from 0.4 mm to 1.25 mm, particularly from 0.5 mm to 0.9 mm. Alternatively, a sealing layer is provided on the bottom surface of the head 110, in the area surrounding the annular groove 111. This layer can be a sealant layer and its thickness can be from 0.05 mm to 0.7 mm, particularly from 0.15 mm to 0.45 mm. Alternatively, the sealing layer can be provided on both the inner wall of the annular groove and on the bottom surface in the area surrounding the annular groove 111. In this way, a sealing contact is achieved between the head of the self-tapping screw 100 and the surface of the first member 11.
[0039] from Figure 1 It can also be seen that the head 110 of the self-tapping screw 100 also has an operating portion 112, which is a recessed portion, for cooperating with a screwing tool to screw the self-tapping screw into the component to be connected. Alternatively, the operating portion can also be implemented as a protrusion extending from the body of the head 110. Or, the outer surface of the head 110 has an operating surface for cooperating with a screwing tool; exemplarily, the upper part of the head is implemented as a hexagonal nut shape, which serves as the operating portion.
[0040] Furthermore, regarding one embodiment of the connection structure according to this disclosure, from Figure 1As can be seen, a boss (not shown as a reference numeral for clarity) is provided on the surface of the second member 12 opposite to the first member 11. This boss is passed through by the self-tapping screw 100, and the sealing layer of the sealing thread section 121 is pressed against the wall of the inner slot formed therein. This boss helps to improve the strength of the fastening connection, which is particularly advantageous when the components to be connected are thin plates. It should be noted that a boss may be provided on the surface of the first member 11 facing the head 110 of the self-tapping screw 100, or simultaneously on the surface of the second member 12 opposite to the first member 11 and on the surface of the first member 11 facing the head 110 of the self-tapping screw 100.
[0041] from Figure 1 It can also be seen that, in the connected state, the sealing thread section 121 is located only in the second member 12. However, it is also feasible for the sealing thread section 121 to extend only a portion of the thickness of the second member 12 along the axial direction, that is, the external threads of the sealing thread section 121 (including the sealing layer thereon) only have a sealing fit with a portion of the inner groove formed by the shaped thread section 122 of the second member 12. Alternatively, the sealing thread section 121 may extend to the entire thickness of the second member 12 along the axial direction and a portion of the thickness of the first member 11 along the axial direction. In the embodiments of this disclosure, the fit length between the sealing thread section and the inner groove in the member to be connected is not limited and can be selected according to the specific circumstances.
[0042] The embodiments and examples presented herein are provided to illustrate embodiments of this disclosure and its particular applications, thereby enabling those skilled in the art to implement and use this disclosure. However, those skilled in the art should understand that the above description and examples are provided for ease of illustration and example only. The descriptions presented are not intended to cover all aspects of this disclosure or to limit this disclosure to its precise forms.
Claims
1. A self-tapping screw comprising a head and a threaded rod extending axially from the head, the threaded rod including a sealing thread section and a forming thread section, wherein, The sealing thread section is closer to the head than the forming thread section. A sealing layer is provided on the outer surface of the sealing thread section. The sealing thread section is characterized in that, in the cross-section along the axial direction, the cross-sectional area of the external thread of the sealing thread section is greater than the cross-sectional area of the external thread of the forming thread section. The sealing layer of the sealing thread section can be pressed against the wall of the inner groove formed by the forming thread section.
2. The self-tapping screw according to claim 1, characterized in that, The cross-sectional area of the external thread in the sealing thread section is 0.05 mm larger than the cross-sectional area of the external thread in the forming thread section. 2 up to 0.5mm 2 ; And / or, the major diameter of the external thread of the sealing thread section is 0.05 mm to 0.5 mm larger than the major diameter of the external thread of the forming thread section.
3. The self-tapping screw according to claim 1, characterized in that, The thickness of the sealing layer in the sealing thread section is 0.04 mm to 1 mm.
4. The self-tapping screw according to claim 1, characterized in that, An annular groove is provided on the bottom surface of the head facing the screw, the annular groove surrounds the screw on the outside and one end is connected to the screw.
5. The self-tapping screw according to claim 4, characterized in that, A sealing layer with a thickness of 0.4 mm to 1.25 mm is provided on the inner wall of the annular groove.
6. The self-tapping screw according to claim 4, characterized in that, A sealing layer with a thickness of 0.05 mm to 0.7 mm is provided on the portion of the bottom surface of the head that surrounds the annular groove.
7. The self-tapping screw according to claim 1, characterized in that, A tapered entry section is provided at the end of the screw away from the head, which gradually narrows in the direction away from the head.
8. The self-tapping screw according to claim 1, characterized in that, A rod section is also provided between the head and the sealing thread section, and no threads are provided on its outer surface.
9. A connection structure, characterized in that, It includes a first component, a second component, and a self-tapping screw according to any one of claims 1 to 8, the self-tapping screw being used to connect the first component and the second component, wherein an inner groove is formed in the first component and the second component by the shaped thread section, and the sealing thread section is pressed against the wall surface of the inner groove with its sealing layer.
10. The connection structure according to claim 9, characterized in that, A boss is provided on the surface of one of the first and second components that is opposite to the other component, and the boss is passed through by the self-tapping screw in the connected state.