Screw for high-strength plate without pre-punched hole

Abstract

The application discloses a screw for high-strength plate without a prefabricated hole and belongs to the field of screw processing. The screw comprises a driving end, a threaded part, a connecting section and a drilling section arranged in sequence from a head to a tail, the threaded part, the connecting section and the drilling section are arranged on a screw rod, and the screw rod is coaxially arranged with the driving end; the drilling end is provided with a tail arc, when a longitudinal section of the tail is designed as an R angle shape, the R angle size is designed in the range of R15-R25, and when the longitudinal section of the tail is designed as an angle, the double-side angle is designed in the range of 22-40 degrees. The patent improves the size and shape of the drilling position of the non-threaded section of the tail of the flow-drilling screw, that is, under the premise that the cold heading and the wire drawing process can be realized, the diameter difference of the circumscribed circle and the inscribed circle of the triangular cross section of the tail and the appropriate shape of the tail are optimized, so that the drilling penetration of the product to the flow-drilling function of the high-strength plate is enhanced, and the application does not increase the process cost and is convenient and effective to implement.

Description

Technical Field

[0001] This invention relates to the field of screw processing, and more particularly to a screw for high-strength plates without pre-drilled holes. Background Technology

[0002] With the continuous growth of new energy vehicles, the safety requirements for these products are also increasing. This is especially true for connections in specific locations, such as those between high-strength steel plates and aluminum plates or steel-aluminum hybrid plates. In these cases, the steel plates are typically pre-drilled or installed without pre-drilled holes, provided the tensile strength is below 500MPa and the thickness does not exceed 1.2mm. For connections between high-strength steel plates (600MPa-800MPa) and aluminum plates with a thickness greater than or equal to 1.2mm, pre-drilled holes are often used due to the difficulty of drilling through the high strength of the steel plate, and the differences in thermal conductivity and ductility between the steel and aluminum plates, which make it difficult to integrate the different installation parameters of the flow drill screws.

[0003] Pre-drilled holes increase the complexity of the process and result in excessively long processing times, making it difficult to meet the current demands for high-strength connections and rapid processing. In addition, there is a risk that the center of the installation positioning hole may be inaccurate after drilling, leading to connection failure. Furthermore, subsequent connection operations may cause secondary damage to the steel plate, affecting the overall connection strength. Summary of the Invention

[0004] To solve the above-mentioned technical problems, the present invention provides a screw for high-strength plates without pre-drilled holes.

[0005] The technical solution of this invention is: screws for high-strength plates without pre-drilled holes, comprising: The drive end, threaded part, connecting section and drilling section are arranged sequentially from head to tail. The threaded part, connecting section and drilling section are arranged on the screw, and the screw and drive end are arranged coaxially. The drilled end is designed with a rounded tail. When the longitudinal section of the tail is designed as an R-angle shape, the R-angle size design range is R15-R25. When the longitudinal section of the tail is designed as an angle, the bilateral angle design range is 22-40 degrees.

[0006] Furthermore, the radius (R) tolerance is 2mm, and the angle tolerance is within 3°.

[0007] Furthermore, the radius (R) angle is measured by shifting the radius 2mm from the tip of the product's end to the arc segment.

[0008] Furthermore, the difference in diameter between the circumcircle and incircle of the triangular cross-section of the tail arc and straight section is guaranteed to be at least 0.15mm and constant, with a maximum difference not exceeding 0.5mm. The difference measurement area extends from the point where the diameter of the tail circumcircle is at most 2mm greater to the axial section of the threaded area. The constant tolerance is within 0.05mm.

[0009] Furthermore, the differential is designed to be between 0.2 and 0.3 mm.

[0010] Furthermore, the driving end can be either an external drive or an internal drive slot. An external drive is an external hexagonal drive, driven by a wrench or socket; an internal drive is a flathead, Phillips, triangular, or internal hexagonal drive, connected and driven by a screwdriver, etc.

[0011] Furthermore, a receiving groove is provided on the side of the drive end near the threaded portion, and the receiving groove is located outside the screw diameter.

[0012] Furthermore, the threaded segment includes a thread tightening area and a self-tapping thread area, with the thread tightening area located near the drive end.

[0013] The beneficial technical effects of this invention are as follows: This patent improves the size and shape of the unthreaded section of the flow drill screw by designing and improving the drilling part. That is, under the premise that cold heading and thread rolling processes are feasible, the diameter difference between the circumcircle and the incircle of the triangular cross section of the tail and the appropriate tail shape are optimized by design to enhance the drilling penetration of the product for high-strength boards. This invention does not increase the process cost and is convenient and effective to implement. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of a screw.

[0015] Figure 2 This is a schematic diagram of the driver side.

[0016] Figure 3 This is a schematic diagram for measuring the diameter difference of screws.

[0017] Figure 4 It is a schematic diagram of a triangular cross section and its circumcircle and incircle (shown by dashed lines).

[0018] Figure 5 Product illustration with the tail section designed at an angle. Figure 6 This is a schematic diagram of a cold heading blank.

[0019] Figure 7Parameter settings for the contact panel stage of high-strength steel DP800 1.4mm + aluminum EN 1706 AC-43500-T7 4mm and high-strength steel DP600 1.2mm + aluminum EN 1706 AC-43500-T7 4mm.

[0020] Figure 8 for Figure 7 Parameter settings for the overlapping flow drilling stage. Figure 9 for Figure 7 Parameter settings for the tapping stage of lapped threads.

[0021] Figure 10 for Figure 7 Parameter settings for the tightening stage of the lapped thread.

[0022] Figure 11 , Figure 12 The graph shows the test connection results for high-strength steel DP800 1.4mm + aluminum EN 1706 AC-43500-T7 4mm.

[0023] Figure 13 This is a picture of the actual object after the first type of connection.

[0024] Figure 14 for Figure 13 A torn cross-section image after connection.

[0025] Figure 15 , Figure 16 The graph shows the test connection results for high-strength steel DP600 1.2mm + aluminum EN 1706 AC-43500-T7 4mm.

[0026] Figure 17 This is a picture of the actual object after the second type of connection.

[0027] Figure 18 This is a torn cross-section image after the second type of connection.

[0028] Figure 19 The parameter settings are for the contact panel stage of the actual measured aluminum material EN 1706 AC-43500-T7 4mm + high-strength steel DP600 1.2mm.

[0029] Figure 20 for Figure 19 Parameter settings for the overlapping flow drilling stage.

[0030] Figure 21 for Figure 19 Parameter settings for the tapping stage of lapped threads.

[0031] Figure 22for Figure 19 Parameter settings for the tightening stage of the lapped thread.

[0032] Figure 23-24 The graph shows the test connection results for aluminum material EN 1706 AC-43500-T7 4mm + high-strength steel DP600 1.2mm.

[0033] Figure 25 for Figure 23 Images of the connected product.

[0034] Figure 26 for Figure 25 A torn cross-section image after connection. Detailed Implementation

[0035] In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0036] See appendix Figure 1-26 The screw shown for high-strength plates without pre-drilled holes includes a drive end, a threaded portion, a connecting section, and a drilled section arranged sequentially from head to tail. The threaded portion, connecting portion, and drilled section are arranged on the screw rod, and the screw rod and the drive end are arranged coaxially. The drilled end is designed with a rounded tail. When the longitudinal section of the tail is designed as an R-angle shape, the R-angle size design range is R15-R25. When the longitudinal section of the tail is designed as an angle, the bilateral angle design range is 22-40 degrees.

[0037] Furthermore, the radius (R) tolerance is 2mm, and the angle tolerance is within 3°.

[0038] Furthermore, the radius (R) angle is measured by shifting the radius 2mm from the tip of the product's end to the arc segment.

[0039] Furthermore, the difference in diameter between the circumcircle and incircle of the triangular cross-section of the tail arc and straight section is guaranteed to be at least 0.15mm and constant, with a maximum difference not exceeding 0.5mm. The difference measurement area extends from the point where the diameter of the tail circumcircle is at most 2mm greater to the axial section of the threaded area. The constant tolerance is within 0.05mm.

[0040] Furthermore, the differential is designed to be between 0.2 and 0.3 mm.

[0041] Furthermore, the driving end can be either an external drive or an internal drive slot. An external drive is an external hexagonal drive, driven by a wrench or socket; an internal drive is a flathead, Phillips, triangular, or internal hexagonal drive, connected and driven by a screwdriver, etc.

[0042] Furthermore, a receiving groove is provided on the side of the drive end near the threaded portion, and the receiving groove is located outside the screw diameter.

[0043] Furthermore, the threaded segment includes a thread tightening area and a self-tapping thread area, with the thread tightening area located near the drive end.

[0044] This patent improves the size and shape of the unthreaded section of the flow drill screw by designing and refining the drilling area. Under the premise that cold heading and thread rolling processes are feasible, the difference between the diameters of the circumcircle and the incircle of the triangular cross section at the tail and the appropriate tail shape are optimized to enhance the drilling penetration of the product for high-strength boards. This invention does not increase process costs and is convenient and effective to implement.

[0045] See appendix Figure 3 The diagram shows the measurement of the diameter difference between the circumcircle and incircle of the triangular cross-section of the tail arc and straight section. Figure 4 This is a schematic diagram of the triangular cross-section of the tail arc and straight section. Measurements were taken using a coordinate measuring machine. Figure 3 The diameters of the circumcircle and incircle of the cross-section at point 1-1 are measured every 0.3-0.5 mm along the longitudinal direction of the product from point 1-1 up to point n. The circumcircle diameter at point n is at most 2 mm, but is usually 1-2 mm. The difference between the circumcircle and incircle diameters of each cross-section is calculated, ensuring that the difference is constant (within a constant tolerance of 0.05 mm) and meets the minimum requirement of 0.15 mm and the maximum requirement of 0.5 mm. The difference from point n to the tail tip will decrease and is not constant. Figure 4 A schematic diagram of a triangular cross section and its circumcircle and incircle (shown by dashed lines).

[0046]

[0047] Figure 1 The 11 measurement areas are designed with a radius (R) at the tail. The measurement should be taken by shifting the measurement area 2mm from the tip of the product's tail end before selecting the arc segment. The total length of the unthreaded section at the tail end (additional lengths at points 10 and 11 plus 2mm) must be greater than the total thickness of the mounting plate without pre-drilled holes. Figure 5 This is a schematic diagram of a product with an angled tail section. To ensure that the difference between the circumscribed circle diameter and the inscribed circle diameter of the tail section meets the requirements after thread rolling, both the self-tapping thread section and the tail forming section of the cold heading blank are designed with triangular cross-sections. Furthermore, to reduce the pressure during the thread rolling process and tail deformation, the cold heading blank is designed with a double-segment triangular cross-section. Figure 6 This is a schematic diagram of a cold heading blank.

[0048] To demonstrate the actual connection test results of the product and its potential applications, the following test results are used as actual test cases to illustrate the results of two high-strength steel + aluminum connections and one aluminum + high-strength steel connection. Figure 7-10To test the connection parameter settings for four stages of lap joint assembly of two types of high-strength steel + aluminum materials, one lap joint was 1.4mm high-strength steel DP800 + 4mm aluminum EN 1706 AC-43500-T7, and the other lap joint was 1.2mm high-strength steel DP600 + 4mm aluminum EN 1706 AC-43500-T7. Figure 7 Parameter settings for these two overlapping contact panel stages, Figure 8 Parameter settings for these two overlapping flow drilling stages. Figure 9 Parameter settings for the tapping stage of these two types of lap joint threads. Figure 10 Parameter settings for the tightening stage of these two types of lap joint threads. Figure 11 , Figure 12 The graph shows the test connection results for high-strength steel DP800 1.4mm + aluminum EN 1706 AC-43500-T7 4mm. Figure 13 This is a picture of the actual product after the link is established. Figure 14 This is a torn cross-sectional image after the connection. Figure 15 , Figure 16 The graph shows the test connection results for a 1.2mm high-strength steel DP600 + a 4mm aluminum alloy conforming to EN 1706 AC-43500-T7. Figure 17 This is a picture of the actual product after the link is established. Figure 18 This is a torn cross-sectional image after the connection. Figure 19-22 The connection parameter settings for the four stages of the actual measured assembly of aluminum material EN 1706 AC-43500-T7 4mm + high-strength steel DP600 1.2mm overlap are as follows: Figure 19 Parameter settings for this type of overlapping contact panel stage. Figure 20 Parameter settings for this type of overlapping flow drilling stage. Figure 21 Parameter settings for the tapping stage of this type of lap joint thread. Figure 22 The parameter settings for the thread tightening stage of this type of lap joint. Figure 23-24 The graph shows the test connection results for aluminum alloy EN1706 AC-43500-T7 4mm + high-strength steel DP600 1.2mm. Figure 25 This is a picture of the actual product after the link is established. Figure 26 This is a torn cross-sectional image after the connection.

[0049] The test results show that, using the screws of this application, a hybrid connection of high-strength steel plates with a tensile strength of 600-800 MPa and a thickness greater than or equal to 1.2 mm can be achieved with aluminum plates. Furthermore, from the attached... Figure 13-14 Hole-free connection of high-strength steel plates has been achieved in 17-18 and 25-26.

[0050] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A screw for high-strength plates without pre-drilled holes, characterized in that, include: The drive end, threaded part, connecting section and drilling section are arranged sequentially from head to tail. The threaded part, connecting section and drilling section are arranged on the screw, and the screw and drive end are arranged coaxially. The drilled end is designed with a rounded tail. When the longitudinal section of the tail is designed as an R-angle shape, the R-angle size design range is R15-R25. When the longitudinal section of the tail is designed as an angle, the bilateral angle design range is 22-40 degrees.

2. The screw for high-strength plates without pre-drilled holes according to claim 1, characterized in that: The radius (R) tolerance is 2mm.

3. The screw for high-strength plates without pre-drilled holes according to claim 1, characterized in that: The angular tolerance is within 3°.

4. The screw for high-strength plates without pre-drilled holes according to claim 1, characterized in that: The radius (R-angle) is measured by shifting the radius 2mm from the tip of the product's end along the arc segment.

5. The screw for high-strength plates without pre-drilled holes according to claim 1, characterized in that: The difference between the diameters of the circumcircle and incircle of the triangular cross-section of the tail arc and straight section is guaranteed to be at least 0.15mm and constant, and at most 0.5mm. The difference measurement area is the axial section from the point where the diameter of the tail circumcircle is at most 2mm greater to the threaded area.

6. The screw for high-strength plates without pre-drilled holes according to claim 5, characterized in that: The constant tolerance for the difference is within 0.05 mm.

7. The screw for high-strength plates without pre-drilled holes according to claim 5, characterized in that: The difference is designed to be between 0.2 and 0.3 mm.

8. The screw for high-strength plates without pre-drilled holes according to claim 1, characterized in that: The driving end can be either an external driving slot or an internal driving slot.

9. The screw for high-strength plates without pre-drilled holes according to claim 1, characterized in that: A receiving groove is also provided on the side of the drive end near the threaded portion, and the receiving groove is located outside the screw diameter.

10. The screw for high-strength plates without pre-drilled holes according to claim 1, characterized in that: The threaded section includes a sequential thread tightening area and a self-tapping thread area, with the thread tightening area located near the drive end.

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