CN215444700U - Self-tapping screw - Google Patents

Abstract

The utility model discloses a self-tapping screw, which comprises a first component and a second component, wherein the first component is positioned in the second component and is processed into a main body, the main body is provided with a tip part, a rod part with external threads and a head part with a driving groove, the tip part is connected with the head part through the rod part, the tip part is the part of the first component, and the hardness of the first component is greater than that of the second component; the utility model ensures the strength, reduces the production cost and has stable structure.

Description

Self-tapping screw

Technical Field

The present invention relates to a self-tapping screw.

Background

Self-tapping screws generally refer to pointed, coarse, hard-textured screws. Since the self-tapping screw does not need to be drilled on a fixture in the fastening process, the requirement on the hardness of the self-tapping screw is high, the corresponding production cost is increased, and how to reduce the overall production cost on the premise of ensuring the hardness becomes a problem which needs to be solved urgently by a person skilled in the art.

Disclosure of Invention

The utility model mainly solves the technical problem of providing a self-tapping screw.

The technical scheme adopted by the utility model for solving the technical problems is as follows: the utility model provides a self-tapping screw, wherein, includes first part and second part, and the first part is located the processing of second part and forms the main part, is equipped with the tip, takes the pole portion of external screw thread and has the head of driving groove on the main part, and the tip passes through the pole portion to be connected with the head, and the tip is the part of first part, and the hardness of first part is greater than the hardness of second part.

With such a self-tapping screw arrangement, since the hardness of the first member is greater than that of the second member, the cost of the first member is higher than that of the second member, for example, the first member is a conventional material, and then the production cost is reduced by the arrangement of the second member. The point portion is the part of first part to guarantee that self tapping screw is whole when boring into the fixture, normal level is guaranteed to its intensity, and through first part and the combination of second part, at self tapping pivoted in-process, the wearability that is located outside second part is less than the wearability of first part, so formed the autogenous grinding effect, make the sharpness of external screw thread better, promoted holistic automatic speed.

Wherein the drive slot is also part of the first part.

The driving groove is also part of the first part, so that the stability of the external driving tool is kept at a normal level and the external driving tool is not easy to wear during driving. In a similar way, when the material of the second part is consistent with that of normal production, the same processing cost is ensured, and the self-tapping screw adopting the structure has higher strength, low cost and good drilling effect.

Wherein the cross-sectional dimension of the first member is two-thirds to four-fifths of the cross-sectional dimension of the shaft portion.

The limitation of the size of the cross section is adopted, so that the overall strength is further ensured not to be influenced by adopting poor materials.

Wherein the external threads are arranged at equal intervals.

Wherein the external threads are arranged at variable intervals.

Wherein the pitch of the external thread is gradually increased from the tip.

The external thread of the tip part is denser, so that the self-tapping screw can be driven into a fixed object at a higher speed.

Wherein the pitch of the external thread is gradually reduced from the tip.

Adopt the point portion to be dredged, the terminal denser setting of pole portion for self tapping screw is at fixed in-process, and the piece of inside production can be discharged outside the self tapping screw fast, thereby prevents the overheated fracture that takes place of pole portion.

Wherein, the tip part is provided with an inwards concave cambered surface.

Through the setting of indent cambered surface for the sharpness of point portion is better, imbeds in the fixture more easily, realizes the prepositioning effect.

Wherein, the driving groove is a straight groove, a cross groove or a meter-shaped groove.

The driving groove can be adjusted according to actual requirements.

Drawings

FIG. 1 is a cross-sectional view showing the fitting of a first member to a second member in embodiment 1 of the present invention;

FIG. 2 is a schematic structural view of a main body in embodiment 1 of the present invention;

FIG. 3 is a sectional view of a main body in embodiment 1 of the utility model;

FIG. 4 is a sectional view of a main body in embodiment 2 of the utility model;

fig. 5 is a sectional view of the body in embodiment 3 of the present invention.

Detailed Description

Example 1:

referring to fig. 1-3, a self-tapping screw includes a first member 1 and a second member 2, the first member 1 and the second member 2 being formed to form a body 3.

The specific structure is that, in the initial state, the first component 1 is embedded in the second component 2 to form a steel wire structure, that is, the two components cooperate to form a steel wire, and the processing of the composite material herein is the prior art, and thus the details are not repeated in this embodiment. Here, the strength of the first member 1 is greater than that of the second member 2, so that the wear resistance of the first member 1 is greater than that of the second member 2. As a simple example, the reduction of the processing costs is achieved when the first component 1 is a normal self-tapping carbon steel and the second component 2 is a cheaper carbon steel with respect to the normal carbon steel, whereby the same strength is achieved, where the higher the price, the stronger the carbon steel. For another example, when the second component 2 is a carbon steel with normal tapping screws and the first component 1 is a carbon steel which is relatively expensive compared to the normal carbon steel, the strength of the second component is much stronger than that of the first component on the premise of not greatly reducing the cost, so that the second component is in active advantage in the process of market competition. Furthermore, the first member 1 and the second member 2 are coaxially arranged.

The wire is machined to form a body 3, the body 3 being provided with a tip 31, a shank 32 with external threads 321 and a head 33 with a drive groove 331.

The tip 31 is mainly a part of the first member 1, and the second member 2 covered on the tip 31 is completely eliminated by processing, so that the tip 31 is formed by the part of the first member 1, and the strength of the tip 31 is ensured, so that the tip can enter the fixture more quickly in the drilling process. Further, the tip 31 is provided with a concave arc 311. Through the setting of indent cambered surface 311 for the sharpness of point 31 is better, imbeds in the fixture more easily, realizes the prepositioning effect.

The rod 32 is provided with an external thread 321, and in this embodiment, the external thread 321 extends from the tip 31 to the top end of the rod 32 at equal intervals. Here, the external thread 321 is a combination of the second component 2 and the first component 1, the first component 1 is located inside the second component 2, when the tapping screw starts to be drilled into a fixed object, in the rotating process, because the wear resistance of the second component 2 is smaller than that of the first component 1, the second component 2 is worn, and the first component 1 located inside is gradually exposed to form a self-grinding effect, so that the overall sharpness of the external thread 321 is increased, and the tapping drilling efficiency is higher.

The shape of the head 33 can be defined according to practical requirements, such as a frustum shape, a truncated cone shape, and the like, and in this embodiment, the head 33 is arranged in a truncated cone shape. The head 33 is provided with a driving groove 331, and the driving groove 331 is used for realizing an integral rotation effect in cooperation with an external driving tool. The driving groove 331 is a straight groove, a cross groove or a cross groove. The driving slot 331 can be adjusted according to actual requirements. In the embodiment, the driving recess 331 is a cross recess.

The head 33 is larger in size than the shaft 32 as a whole, and the driving groove 331 is a part of the first member 1, so that the external driving tool is stable and is not easily worn during driving.

The cross-sectional dimension of the first component 1 is two thirds to four fifths of the cross-sectional dimension of the stem portion 32. The limitation of the size of the cross section is adopted, so that the overall strength is further ensured not to be influenced by adopting poor materials. In this embodiment, the cross-sectional dimension of the first member 1 is seven-tenth of the cross-sectional dimension of the shaft portion 32.

With such a self-tapping screw arrangement, since the hardness of the first member 1 is greater than that of the second member 2, the cost of the first member 1 is higher than that of the second member 2, for example, the first member 1 is a conventional material, and then the production cost is reduced by the arrangement of the second member 2. The point 31 is the part of first part 1 to guarantee that self tapping screw is whole when boring into the fixture, its intensity guarantees normal level, and through first part 1 and the combination of second part 2, at self tapping pivoted in-process, the wearability that is located outside second part 2 is less than the wearability of first part 1, so formed the autogenous grinding effect, make the sharpness of external screw thread 321 better, promoted holistic automatic speed.

Example 2:

referring to fig. 4, embodiment 2 is different from embodiment 1 in that the external threads 321 are provided at a variable pitch, and the pitch of the external threads 321 is gradually increased from the tip 31. The use of the dense external thread 321 of the tip 31 allows the self-tapping screw to be driven into a fixture at a faster speed.

Example 3:

referring to fig. 5, embodiment 3 is different from embodiment 1 in that the external threads 321 are provided at a variable pitch, and the pitch of the external threads 321 is gradually reduced from the tip 31. Adopt sharp portion 31 to be sparser, the terminal denser setting of pole portion 32 for self tapping screw is at fixed in-process, and the piece of inside production can be discharged outside the self tapping screw fast, thereby prevents that pole portion 32 from overheated emergence fracture.

Claims (9)

1. A self-tapping screw characterized in that: including first part and second part, first part is located the processing of second part and forms the main part, is equipped with the tip in the main part, the pole portion of outband screw thread and has the head in drive groove, and the tip passes through the pole portion to be connected with the head, and the tip is the part of first part, and the hardness of first part is greater than the hardness of second part.

2. A self-tapping screw as defined in claim 1, wherein: the drive slot is also part of the first part.

3. A self-tapping screw as defined in claim 1, wherein: the cross-sectional dimension of the first member is two-thirds to four-fifths of the cross-sectional dimension of the shaft.

4. A self-tapping screw as defined in claim 1, wherein: the external threads are arranged at equal intervals.

5. A self-tapping screw as defined in claim 1, wherein: the external threads are arranged at variable intervals.

6. A self-tapping screw as defined in claim 5, wherein: the pitch of the external thread gradually increases from the tip.

7. A self-tapping screw as defined in claim 5, wherein: the pitch of the external thread is gradually reduced from the tip.

8. A self-tapping screw as defined in claim 1, wherein: the tip part is provided with an inward concave cambered surface.

9. A self-tapping screw as defined in claim 1, wherein: the driving groove is a straight groove, a cross groove or a meter-shaped groove.

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