TWI595950B - Screw tap - Google Patents

Description

Wire attack

The invention relates to a wire tapping, in particular to a wire tapping which can reduce the cutting resistance and is not easy to break during processing.

According to FIG. 1 and FIG. 2, it is a conventional extrusion wire tapping 1 and has a rod portion 2 at one end and a tooth portion 3 at the other end. The rod portion 2 is for holding an instrument, and the teeth are The outer edge of the portion 3 is provided with a plurality of cutting edges 4 along the axial direction. The periphery of each of the cutting edges 4 has four cutting points 5, and has a convex curved cutting surface 6 between the two adjacent cutting points 5. Among them, the extrusion tap 1 is a wire tap which is formed into a thread in a drill hole 7 by means of rotary compression molding, and is more suitable for use in a material having ductile plastic working, such as an aluminum alloy.

However, the radius of curvature of the cutting camber 6 determines the extent to which the tooth 3 occupies the bore 7 when the tooth 3 makes an internal thread in the bore 7. In short, when the outer diameter of the tooth portion 3 is fixed, the smaller the radius of curvature of the cutting curved surface 6, the more the area of the tooth portion 3 occupies the borehole 7, so that the extrusion tapping 1 is made when the internal thread is made. The resistance encountered by the tooth part 3 is increased, and the probability of squeezing the tapping and breaking 1 is increased; in addition, the squeezing wire tapping 1 does not generate chips during processing, so the groove is discharged when the tooth portion 3 has no swarf. The groove, but in order to provide smoothness during cutting, the gap between each cutting surface 6 and the bore 7 forms a groove 8 into which the cutting oil can be injected, so that the area of the area occupied by the tooth 3 is larger. More often, the smaller the groove 8, the less cutting oil it can inject.

In other conventional wire attacks, an oil groove is recessed in the axial direction of the tooth portion 3 to increase the amount of cutting oil injected, but once the tooth portion 3 is recessed, the structure of the tooth portion 3 is lowered. Strength, also facing the problem of increased probability of wire breakage.

Therefore, how to overcome the shortcomings of the prior art is the subject of the present invention.

In order to solve the above problems, the present invention discloses a wire tapping, wherein a thread segment of a tooth portion has a plurality of cutting edges, each cutting edge has four cutting points, and two cutting points have two symmetric cutting surfaces and It is located between the two cutting arc faces and is connected to one of the retreating planes, thereby providing a small cutting resistance, so that the wire tapping is not easily broken during processing.

In order to achieve the above object, the present invention provides a wire tapping having a stem portion at one end and a square columnar tooth portion at the other end, the outer edge of the tooth portion is circumferentially disposed with a thread segment, and the thread segment has a plurality of thread segments. a cutting edge, each of the edges of the blade has four cutting points, and two symmetrically arranged cutting arc surfaces between each two adjacent cutting points and a retracting plane between the two cutting arc surfaces and connected thereto, wherein The two cutting arcs are formed by the same radius.

Wherein, each of the two adjacent cutting points has an imaginary arc surface, and the imaginary arc surface is located outside the two cutting arc surfaces, and the curvature radius of the two cutting arc surfaces is larger than the radius of curvature of the imaginary curved surface.

Wherein, the vertical distance from the center position of the retreat plane to the imaginary arc surface is smaller than the length of the retreat plane.

Wherein, the vertical distance from the center position of the retreat plane to the imaginary arc surface is less than 1/2 of the length of the retreat plane.

Wherein, the length of the escape plane is less than 1/2 of the distance between two adjacent cutting points.

Thereby, the cutting edge of the invention occupies a small area of the borehole, reduces the resistance encountered when the tooth is rotated, and reduces the probability of wire breakage.

For the convenience of the description, the central idea expressed by the present invention in the column of the above summary of the invention is expressed by the specific embodiments. The various items in the embodiments are set forth in proportion to the description and not in the

Referring to FIG. 3 to FIG. 6, the wire tapping 100 of the present invention is an extruded wire tapping for tapping and twisting a thread 200 of a drill hole 200. The wire tap 100 has a rod portion 10 at one end and a square columnar tooth portion 20 at the other end. The rod portion 10 is held by a tapping device.

The tooth portion 20 has an outer edge which is circumferentially disposed with a threaded section 21. The threaded section 21 has a plurality of cutting edges 22, and the periphery of each of the cutting edges 22 has four cutting points 23, and is cut every two adjacent A cutting arc surface 24 having two symmetric arrangements between points 23 and between the two cutting arc surfaces 24 is connected to one of the retreating planes 25. Among them, the two cutting arc faces 24 are formed by the same radius.

In addition, there is an imaginary curved surface C between every two adjacent cutting points 23, the imaginary curved surface C is equal to the shape of the tooth of the conventional wire tapping tool, and the imaginary curved surface C is located outside the two cutting curved faces 24, And the radius of curvature of the two cutting arc faces 24 is larger than the radius of curvature of the imaginary arc surface C, so that the arcs of the two cutting arc faces 24 are more moderate, and closer to the central axis X of the cutting edge 22 than the imaginary arc surface C.

Further, the vertical distance D from the center position of the escape plane 25 to the imaginary curved surface C is smaller than the length L of the escape plane 25. In the present invention, the vertical distance D from the center position of the escape plane 25 to the imaginary curved surface C is less than 1/2 of the length L of the escape plane 25.

Further, the length L of the escape plane 25 is less than 1/2 of the distance L1 between the two adjacent cutting points 23.

As shown in FIG. 5 and FIG. 6, it is a schematic diagram of the state of use of the present invention. The wire tap 100 of the present invention is shown to be rotationally compression molded into the thread 200, wherein the cutting arc surface 24 of the cutting edge 22 has a curvature radius larger than the radius of curvature of the virtual arc surface C, so that the arc of the cutting arc surface 24 is relatively The relaxation, together with the relief plane 25, provides that the cutting edge 22 occupies a smaller area of the borehole 200 than the conventional wire tapping tool, thereby reducing the resistance encountered by the tooth 20 during rotation and reducing the tapping. The probability of 100 breaks.

Furthermore, through the formation of the relief plane 25, the gap between the cutting edge 22 and the inner wall of the borehole 200 is increased, so that the cutting oil injection flows or adheres as a path, and the lubrication effect in the wire tapping operation is provided, and the overall effect is enhanced. Durability. Therefore, the present invention retains the structural integrity, and the lubrication effect can be achieved without additionally making a concave oil groove or a slot.

While the invention has been described in terms of a preferred embodiment, the various embodiments may The above embodiments are merely illustrative of the invention and are not intended to limit the scope of the invention. All modifications or changes made without departing from the spirit of the invention are within the scope of the invention.

Conventional part
1‧‧‧Squeeze tapping
3‧‧‧Dental
5‧‧‧cutting point
7‧‧‧Drilling part of the invention
100‧‧ ‧ silk attack
20‧‧‧ teeth
22‧‧‧ cutting edge
24‧‧‧Cutting curved surface
C‧‧‧Imaginary curved surface
D‧‧‧Vertical distance
L1‧‧‧ distance
2‧‧‧ pole
4‧‧‧ cutting edge
6‧‧‧Cutting curved surface
8‧‧‧ trench
10‧‧‧ Rod
21‧‧‧Threaded section
23‧‧‧cutting point
25‧‧‧Withdrawal plane
X‧‧‧ central axis
L‧‧‧ length
200‧‧‧ drilling

[Fig. 1] is a schematic view showing the appearance of a conventional extrusion wire tap. [Fig. 2] is a schematic view showing a state in which a conventional extruded wire is tapped into a drilled hole. FIG. 3 is a schematic view showing the appearance of the wire tapping of the present invention. [Fig. 4] is a schematic view of the end portion of the wire tapping of the present invention. Fig. 5 is a schematic view showing the state of use of the present invention. [Fig. 6] is a schematic view showing the state in which the wire is made in the drill hole in the present invention.

100‧‧ ‧ silk attack

10‧‧‧ Rod

20‧‧‧ teeth

21‧‧‧Threaded section

22‧‧‧ cutting edge

Claims (5)

The utility model relates to a wire tapping, which has a rod portion at one end and a square columnar tooth portion at the other end. The outer edge of the tooth portion is circumferentially arranged with a thread segment having a plurality of cutting edges, each of which has a plurality of cutting edges. The peripheral system has four cutting points, two symmetrically arranged cutting arc surfaces between each two adjacent cutting points and a retreating plane between the two cutting arc surfaces, wherein the two cutting arc surfaces are connected They are formed at the same radius. The wire tap according to claim 1, wherein each of the two adjacent cutting points further has an imaginary arc surface, the imaginary arc surface is located outside the two cutting arc surfaces, and the radius of curvature of the two cutting arc surfaces The system is larger than the radius of curvature of the imaginary arc. The wire tapping of claim 2, wherein a vertical distance from a center position of the retreat plane to the imaginary arc surface is less than a length of the retreat plane. The wire tap according to claim 3, wherein a vertical distance from a center position of the retraction plane to the imaginary arc surface is less than 1/2 of a length of the retreat plane. The wire tap as claimed in claim 1, wherein the length of the retraction plane is less than 1/2 of the distance between two adjacent cutting points.