TWI826157B - Low extrusion resistance screw tap - Google Patents

Abstract

A low extrusion resistance screw tap includes a shaft portion and a thread section. The thread section includes a plurality of teeth surrounding the central axis. The periphery of each tooth includes two first cutting edges and two second cutting edges, wherein a first distance is formed between the two first cutting edges, and a second distance is formed between the two second cutting edges, wherein the first distance is greater than the second distance. Therefore, the periphery of the toothed periphery of the screw tap contains unequal side lengths, so as to achieve a smaller extrusion resistance, thereby lowering the fracture possibility of the screw tap during processing.

Description

Tap with low extrusion resistance

The present invention relates to an extrusion type thread tap, in particular to a thread tap with low extrusion resistance.

As shown in Figure 1, it is a top view of a conventional extrusion type tap 1, which is mainly a tool for forming internal threads in a hole A through plastic processing.

The described thread tap 1 has a tooth portion 2, the cross section of the tooth portion 2 is an equal square, the peripheral ring of the tooth portion 2 is provided with four edge tooth portions 3, and each two adjacent edge tooth portions 3 have an extrusion. Pressure point 4. During the forming process, the four extrusion points 4 of the wire tap 1 will come into contact with the hole A and generate resistance. That is to say, there are four force application points of the wire tap 1 on the inner wall of the hole A. In this way, the extrusion The resistance is large, making the wire tap 1 prone to breakage during processing.

In order to solve the above problems, the present invention discloses a low extrusion resistance thread tap. The peripheral edges of the rib teeth are arranged with unequal lengths, which can provide smaller extrusion resistance and make the tap less likely to break during processing.

To achieve the above object, an embodiment of the present invention provides a tap with low extrusion resistance, which includes a rod portion and a thread segment. The threaded segment extends along one of the mandrels of the rod and is formed at one end of the rod. The threaded segment is provided with a plurality of rib teeth around the mandrel. The periphery of each rib tooth has four extrusion points and two spaced apart ribs. The first cutting edge and two second cutting edges connected between the two first cutting edges, and there is an extrusion point between the adjacent first cutting edges and the second cutting edges, and the threaded section has a through mandrel. and a first transverse axis and a second transverse axis that are not perpendicular to each other. The first transverse axis passes through two of the extrusion points that are far away from each other. The second transverse axis passes through the other two extrusion points that are far away from each other. The first transverse axis passes through the other two extrusion points that are far away from each other. There is a first spacing angle and a second spacing angle between the axis and the second transverse axis. The first spacing angle faces the first cutting edge, the second spacing angle faces the second cutting edge, and the first spacing angle is greater than the second spacing angle. horn.

In another embodiment of the present invention, the first spacing angle is greater than 90 degrees, and the second spacing angle is less than 90 degrees.

In another embodiment of the present invention, the first spacing angle is 93 degrees, and the second spacing angle is 87 degrees.

In another embodiment of the present invention, each first cutting edge includes a first relief surface and first arc edges located on both sides of the first relief surface, and each second cutting edge includes a second relief surface. and second arc edges located on both sides of the second concession surface, and the distance between the two first concession surfaces is greater than the distance between the two second concession surfaces.

In another embodiment of the present invention, the distance between the two first relief surfaces is 1.04mm, and the distance between the two second relief surfaces is 1mm.

In another embodiment of the present invention, the maximum outer diameter of the thread segment is 1.245mm, and the root diameter of the thread segment is 0.95mm.

Another embodiment of the present invention provides a thread tap with low extrusion resistance, which includes a rod portion and a thread segment. The threaded section extends along a mandrel of the shaft and is formed at one end of the shaft. The threaded section is provided with a plurality of ribs around the periphery of the mandrel. The periphery of each rib has four extrusion points and two spacers. There is a first cutting edge provided and two second cutting edges connected between the two first cutting edges, and there is an extrusion point between the adjacent first cutting edge and the second cutting edge, and the threaded segment has A first transverse axis and a second transverse axis passing through the mandrel, a first spacing angle and a second spacing angle between the first transverse axis and the second transverse axis, the first spacing angle facing the first cutting edge, The second spacing angle faces the second cutting edge, and the first spacing angle is greater than the second spacing angle, and there is a first distance between the two first cutting edges, a second distance between the two second cutting edges, and the first The distance is greater than the second distance.

In this way, the present invention adopts the unequal distribution design of the first pitch angle and the second pitch angle. Therefore, during the tapping operation, the force application point is only located at the two diagonal pressing points of the edge teeth, thereby Provides smaller extrusion resistance, making the tap less likely to break during processing.

Exemplary embodiments of the present invention are described in detail below with reference to the accompanying drawings. It is not intended to limit the technical principles of the present invention to the specifically disclosed embodiments, but the scope of the present invention is limited only by the scope of the patent application and covers substitutions, modifications and equivalent.

Please refer to FIG. 2 to FIG. 3 , which is a thread tap 100 with low extrusion resistance according to the present invention. It is an extrusion tap including a rod portion 10 and a thread segment 20 . The threaded section 20 extends along a spindle X of the rod portion 10 and is formed at one end of the rod portion 10 . The rod portion 10 is clamped and fixed by the tapping tool in order to drive the threaded section 20 to tap the internal thread of the hole A.

The thread section 20 is provided with a plurality of rib teeth 21 around the mandrel X. The periphery of each rib tooth 21 has four extrusion points 22 and two spaced apart first cutting edges 23 and two connected to the two first cutting edges 23 . A second cutting edge 24 between the cutting edges 23 . In the embodiment of the present invention, there is a pressing point 22 between the adjacent first cutting edge 23 and the second cutting edge 24 . The maximum outer diameter B of the threaded section 20 is 1.245mm, and the root diameter C of the threaded section 20 is 0.95mm.

There is a first distance D1 between the two first cutting edges 23 , and there is a second distance D2 between the two second cutting edges 24 . The first distance D1 is greater than the second distance D2, so that the four-sided width of the edge teeth 21 is of unequal length.

In the embodiment of the present invention, each first cutting edge 23 includes a first relief surface 231 and first arc edges 232 located on both sides of the first relief surface 231, and one end of each first arc edge 232 is connected to the first relief surface. The other end of the surface 231 is connected to the one pressing point 22 . Each second cutting edge 24 includes a second relief surface 241 and second arc edges 242 located on both sides of the second relief surface 241. One end of each second arc edge 242 is connected to the second relief surface 241, and the other end is connected to Said one squeeze point 22. It should be noted that there is one pressing point 22 between the adjacent first cutting edge 23 and the second cutting edge 24 and between the first arc edge 232 and the second arc edge 242 . The distance between the two first relief surfaces 231 is defined as the first distance D1, and the distance between the two second relief surfaces 241 is defined as the second distance D2. And the distance between the two first relief surfaces 231 (first distance D1) is 1.04 mm, and the distance between the two second relief surfaces 241 (the second distance D2) is 1 mm.

Specifically, through the arrangement of each first relief surface 231 and each second relief surface 241, the gap between the edge teeth 21 and the inner wall of the hole A is increased, so that more cutting fluid can be injected and the tapping 100 operation can be provided. Better lubrication effect.

In the embodiment of the present invention, the thread section 20 has a first transverse axis Y1 and a second transverse axis Y2 that pass through the mandrel X and are not perpendicular to each other. The first transverse axis Y1 passes through two of the extrusion points 22 that are far away from each other. , the second transverse axis Y2 passes through two other extrusion points 22 that are far away from each other. Furthermore, as shown in the figure, the four extrusion points 22 of the present invention are based on the upper right corner and are respectively the first extrusion point 221, the second extrusion point 222, and the third extrusion point 223 in the clockwise direction. and fourth squeeze point 224. The first transverse axis Y1 passes through the first extrusion point 221 and the third extrusion point 223, and the second transverse axis Y2 passes through the second extrusion point 222 and the fourth extrusion point 224.

There is a first spacing angle θ1 and a second spacing angle θ2 between the first transverse axis Y1 and the second transverse axis Y2. The first spacing angle θ1 faces the first cutting edge 23 and the second spacing angle θ2 faces the second cutting edge. 24, and the first spacing angle θ1 is greater than the second spacing angle θ2. In the embodiment of the present invention, the sum of the first spacing angle θ1 and the second spacing angle θ2 is 180 degrees. Preferably, the first spacing angle θ1 is greater than 90 degrees, and the second spacing angle θ2 is less than 90 degrees. More preferably, the first pitch angle θ1 is 93 degrees, and the second pitch angle θ2 is 87 degrees.

To further explain, the first spacing angle θ1 is the angle formed by the line connecting the first extrusion point 221 to the mandrel X and the second extrusion point 222 to the mandrel X, or the angle from the third extrusion point 223 to The angle formed by the mandrel X and the line connecting the fourth extrusion point 224 to the mandrel X. The second spacing angle θ2 is the angle formed by the line connecting the first extrusion point 221 to the mandrel X and the fourth extrusion point 224 to the mandrel X, or from the second extrusion point 222 to the mandrel X and the third The angle formed by the line connecting the three extrusion points 223 to the mandrel X.

As shown in FIG. 3 , the present invention adopts an unequal distribution design of the first spacing angle θ1 and the second spacing angle θ2 between the first transverse axis Y1 and the second transverse axis Y2. Therefore, the four extrusion points 22 are Compared with the inner wall of the hole A, the inner wall is slightly moved inward, forming an unequal diagonal division of the edge teeth 21. During the tapping operation, the force application point is only located at the two diagonal extrusion points 22 of the edge teeth 21. (such as the first extrusion point 221 and the third extrusion point 223, or the second extrusion point 222 and the fourth extrusion point 224), thereby providing smaller extrusion resistance, making it difficult for the thread tap 100 to process Breakage occurs.

Please refer to Figure 4, which is a comparison table of the torque test of the thread tap of the present invention and the thread tap of the comparative example using the brand Kistler-9273 dynamometer (torque sensor). It shows that the maximum torque endured by the thread tap of the invention is 20N-mm, the maximum torque endured by the comparative example wire tap is 31.42N-mm. It can be seen that the resistance of the wire tap of the present invention is less than that of the comparative example wire tap, which makes the wire tap of the present invention less likely to break during processing.

Please refer to 5 again, which is a comparison table of the internal thread thread filling rate (%) of the thread tap of the present invention and the comparative example thread tap. It shows that the thread tapping of the invention can obtain the internal thread thread thread filling rate of 87.13%, compared with the comparative example. The thread filling rate of the internal thread of the wire tapping is very high at 86.44%, which can better achieve the expected tapping effect.

Although the present invention has been described with a preferred embodiment, those skilled in the art can make various modifications without departing from the spirit and scope of the present invention. The aforementioned embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. All modifications or changes that do not violate the spirit of the present invention fall within the scope of the patent application of the present invention.

1: Silk tapping 2: Teeth 3: Edge tooth part 4: Squeeze point A:hole 100: Silk attack 10: Rod 20: Thread section 21: Edge teeth 22: squeeze point 221: First squeeze point 222: Second squeeze point 223: The third squeeze point 224: The fourth squeeze point 23: First cutting edge 231:First concession surface 232: First arc edge 24: Second cutting edge 241:Second concession surface 242:Second arc edge X: mandrel B: Maximum outer diameter C: root diameter D1: first distance D2: second distance Y1: the first horizontal axis Y2: The second horizontal axis θ1: first spacing angle θ2: second spacing angle

[Figure 1] is a schematic diagram of a conventional extrusion type thread tapping in a hole. [Fig. 2] is a schematic diagram of the appearance of the low extrusion resistance tapping of the present invention. [Fig. 3] is a schematic diagram of the appearance of the low extrusion resistance tapping of the present invention in a hole. [Fig. 4] is a comparison table of the maximum torque of tappings of the present invention and comparative examples. [Fig. 5] is a comparison table of thread filling rates of internal threads of the present invention and comparative examples.

A:hole

21: Edge teeth

22: squeeze point

221: First squeeze point

222: Second squeeze point

223: The third squeeze point

224: The fourth squeeze point

23: First cutting edge

231:First concession surface

232: First arc edge

24: Second cutting edge

241:Second concession surface

242:Second arc edge

X: mandrel

B: Maximum outer diameter

C: root diameter

D1: first distance

D2: second distance

Y1: the first horizontal axis

Y2: The second horizontal axis

θ1: first spacing angle

θ2: second spacing angle

Claims (7)

A low extrusion resistance tapping, which includes: a shaft; and A threaded section extends along a mandrel of the shaft and is formed at one end of the shaft. The threaded section is provided with a plurality of rib teeth around the mandrel, and the periphery of each rib tooth has four extrusions. point and two spaced apart first cutting edges and two second cutting edges connected between the two first cutting edges, and there is a gap between the adjacent first cutting edges and the second cutting edges. An extrusion point, the thread section has a first transverse axis and a second transverse axis that pass through the mandrel and are not perpendicular to each other, the first transverse axis passes through two of the extrusion points that are far away from each other, and the third The two transverse axes pass through two other extrusion points that are far away from each other. There is a first spacing angle and a second spacing angle between the first transverse axis and the second transverse axis. The first spacing angle faces the first cutting edge, the second spacing angle faces the second cutting edge, and the first spacing angle is greater than the second spacing angle. The thread tap with low extrusion resistance as claimed in claim 1, wherein the first spacing angle is greater than 90 degrees, and the second spacing angle is less than 90 degrees. The thread tap with low extrusion resistance as claimed in claim 2, wherein the first pitch angle is 93 degrees and the second pitch angle is 87 degrees. The thread tap with low extrusion resistance as claimed in claim 1 or 2, wherein each first cutting edge includes a first relief surface and first arc edges located on both sides of the first relief surface, and each of the first relief surfaces The second cutting edge includes a second relief surface and second arc edges located on both sides of the second relief surface. The distance between the two first relief surfaces is greater than the distance between the two second relief surfaces. The thread tap with low extrusion resistance as described in claim 4, wherein the distance between the two first relief surfaces is 1.04mm, and the distance between the two second relief surfaces is 1mm. The thread tap with low extrusion resistance as claimed in claim 5, wherein the maximum outer diameter of the thread segment is 1.245mm, and the root diameter of the thread segment is 0.95mm. A low extrusion resistance tapping, which includes: a shaft; and A threaded section extends along a mandrel of the shaft and is formed at one end of the shaft. The threaded section is provided with a plurality of ribs around the periphery of the mandrel, and each of the ribs has four edges on its periphery. The extrusion point and two spaced apart first cutting edges and two second cutting edges connected between the two first cutting edges, and the adjacent first cutting edge and the second cutting edge are There is an extrusion point in between, the thread segment has a first transverse axis and a second transverse axis passing through the mandrel, and there is a first spacing angle and a first spacing angle between the first transverse axis and the second transverse axis. second spacing angle, the first spacing angle faces the first cutting edge, the second spacing angle faces the second cutting edge, and the first spacing angle is greater than the second spacing angle, and the two first cutting edges There is a first distance between the two second cutting edges, and there is a second distance between the two second cutting edges, and the first distance is greater than the second distance.

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