CN211939393U - Positive and negative shredding awl - Google Patents

Abstract

The utility model provides a positive and negative awl of shredding relates to screw tap technical field. The positive and negative thread cutting cone comprises a threaded section for cutting threads, wherein the threaded section is provided with a cutting groove and a cutting part, and is characterized in that the cutting part is provided with a cutting front angle and a cutting back angle, the cutting front angle and the cutting back angle are both positioned on a cutting circle which takes the rotating axis of the threaded section as the center, the distance between the cutting part and the cutting circle is a fall, and the fall increases from the cutting front angle to the cutting back angle and then decreases. The cutting relief angle can play a role in correcting the deformation of the thin-wall workpiece in the process of reversely rotating and withdrawing the screw tap.

Description

Positive and negative shredding awl

Technical Field

The utility model relates to a screw tap technical field particularly, relates to a positive and negative awl that shreds.

Background

The screw tap is a cutting tool for processing internal threads, and currently, the screw tap occupies a main position in the internal thread processing, and different screw tap structures are required to deal with the internal threads due to the diversity of the internal thread processing conditions.

In the prior art, the internal thread processing difficulty of a thin-wall workpiece is very high. Due to the thin wall of the workpiece, the screw tap in the prior art has a large contact area with the workpiece, so that the workpiece deforms seriously; or the contact area of the screw tap and the workpiece is small, so that the screw tap has no correction function after the workpiece is deformed. In view of the above, the inventors of the present invention have made a study of the prior art and then have made the present application.

SUMMERY OF THE UTILITY MODEL

The utility model provides a positive and negative shredding awl aims at improving prior art, and the screw tap can not fine processing thin wall work piece internal screw thread problem.

In order to solve the technical problem, the utility model provides a positive and negative awl that shreds, including the screw thread section for cutting the screw thread, this screw thread section is provided with cutting groove and cutting part. The cutting part is provided with cutting rake angle and cutting relief angle, cutting rake angle with cutting relief angle all is located with screw thread section axis of rotation is the cutting circle at center, the cutting part with distance between the cutting circle is the drop, the drop certainly cutting rake angle arrives cutting relief angle's direction increases earlier and then reduces.

As a further optimization, the drop height becomes smaller from the cutting rake angle to the intermediate position of the cutting rake angle and the cutting relief angle; the fall increases in the direction from the intermediate position between the cutting rake angle and the cutting relief angle to the cutting relief angle.

As a further optimization, the transition between the cutting front angle and the cutting rear angle is a circular arc surface transition with the center facing outwards.

As a further optimization, the threaded section is provided with four cutting grooves, and the cutting grooves are all arranged on the threaded section by taking the rotating axis of the threaded section as the center.

By adopting the technical scheme, the utility model discloses can gain following technological effect:

the utility model discloses a screw tap, internal thread of processing thin wall work piece that can be fine. Specifically, when the screw tap is used for machining threads in a forward rotation mode, threads are cut by the cutting front angle, and the cutting rear angle does not contact a workpiece due to elastic deformation in the machining process. After the threads are machined on the cutting front angle, the screw tap reverses and retreats from the threaded hole, and the deformation of the thin-wall workpiece is easily caused in the process of machining the threads by the screw tap through the cutting front angle; in the process of reversely retreating from the threaded hole, the cutting back angle of the screw tap can cut the machined thread, and the deformation of the thin-wall workpiece is corrected, so that the machining yield of the internal thread of the thin-wall workpiece is increased.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention, and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

Fig. 1 is a schematic structural diagram of a tap according to an embodiment of the present invention;

fig. 2 is a schematic cross-sectional view of a thread segment of the tap according to an embodiment of the present invention;

FIG. 3 is a schematic cross-sectional view of a first thread segment of a prior art tap;

FIG. 4 is a schematic cross-sectional view of a second thread segment of a prior art tap;

FIG. 5 is a schematic cross-sectional view of a third thread segment of a prior art tap;

the labels in the figure are: 1-a thread section; 2-a shank segment; 3-cutting a groove; 4-a cutting portion; 5-cutting the rake angle; 6-cutting relief angle; 7-fall; 8-first stage; 9-second section.

Detailed Description

To make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the drawings of the embodiments of the present invention are combined to clearly and completely describe the technical solutions of the embodiments of the present invention, and obviously, the described embodiments are some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention. Thus, the following detailed description of the embodiments of the present invention, presented in the accompanying drawings, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and to simplify the description, but do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," and "fixed" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

In the present disclosure, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may comprise direct contact between the first and second features, or may comprise contact between the first and second features not directly. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

The invention will be described in further detail with reference to the following detailed description and accompanying drawings:

as shown in fig. 1 and 2, in the present embodiment, a positive and negative thread cutting tap includes a handle section 2 and a thread section 1, wherein the handle section 2 can drive the thread section 1 to rotate, and the thread section 1 is provided with a thread for cutting. The threaded section 1 is provided with a cutting groove 3 and a cutting portion 4, and in the present embodiment, the threaded section 1 is provided with 4 cutting grooves 3, and the cutting grooves 3 are all arranged on the threaded section 1 by taking the rotation axis of the threaded section 1 as the center. The cutting portion 4 is a screw thread spirally formed on the screw thread section 1, and the screw threads are separated by 4 cutting grooves 3 to form 4 regions, and each region is composed of a plurality of cutting portions 4 which are arranged up and down in an accumulated manner.

As shown in fig. 2, in the present embodiment, the cutting portion 4 is provided with a cutting rake angle 5 and a cutting relief angle 6, the cutting rake angle 5 and the cutting relief angle 6 are both located on a cutting circle centered on the rotational axis of the screw flight 1, the distance between the cutting portion 4 and the cutting circle is a drop 7, and the drop 7 increases and then decreases in the direction from the cutting rake angle 5 to the cutting relief angle 6. In the present embodiment, the transition between the cutting rake angle 5 and the cutting relief angle 6 is a circular arc surface transition with the center facing outward, and the radius of the transition circular arc is R. The fall 7 is decreased from the cutting front angle 5 to the middle position of the cutting front angle 5 and the cutting rear angle 6; the difference 7 increases from the intermediate position between the cutting rake angle 5 and the cutting relief angle 6 to the cutting relief angle 6. .

In the specific working process, when the tap of the embodiment is used for machining threads in the forward rotation mode, the cutting front angle 5 cuts threads, and the cutting rear angle 6 does not contact with a workpiece because elastic deformation exists in the machining process. After the thread is machined on the cutting front angle 5, the screw tap reversely rotates and retreats from the threaded hole, and the deformation of the thin-wall workpiece is easily caused in the process that the screw tap machines the thread through the cutting front angle 5. In the process of reversely retreating from the threaded hole, the cutting back angle 6 of the screw tap of the scheme can cut the machined thread and correct the deformation of the thin-wall workpiece, so that the machining yield of the internal thread of the thin-wall workpiece is increased.

Compared with the taps in the prior art, the taps in 3 figures are all taps in the prior art as shown in fig. 3, 4 and 5. Where the tap of fig. 3 has no drop 7 in transition between the cutting rake 5 and cutting relief 6 angles, such taps are typically used for tapping small diameter threads. Among these, the tap of fig. 4 has a step 7 at the transition between the cutting rake angle 5 and the cutting relief angle 6, and the step 7 is larger closer to the cutting relief angle 6, and is generally used for work hardening materials and harder materials. In the tap of fig. 5, the transition between the cutting rake angle 5 and the cutting relief angle 6 of the tap is divided into a first segment 8 and a second segment 9, the first segment 8 has no drop 7, and the second segment 9 has a drop 7 and the drop 7 is larger closer to the cutting relief angle 6. This type of tap is suitable for use in the manufacture of large diameter internal threads, the first section 8 providing wear resistance to the tap and the second section 9 reducing the contact area between the tap and the workpiece to reduce heat.

However, the taps of the prior art described above are difficult to meet the requirement for machining the internal thread of the thin-walled workpiece, or the contact area between the cutting portion 4 of the tap and the workpiece is too large, which results in severe deformation of the workpiece; or the contact area of the cutting part 4 of the tap and the workpiece is too small, so that the workpiece is deformed, and the tap has no correction function.

According to the technical scheme of the embodiment, the screw tap has the fall 7 in transition between the cutting front angle 5 and the cutting rear angle 6, so that on one hand, the contact area between the screw tap and a workpiece is not too large, and meanwhile, because the distances from the cutting front angle 5 and the cutting rear angle 6 to the rotating axis of the threaded section 1 are the same, in the process that the screw tap reversely rotates and retreats, the cutting rear angle 6 can correct the deformation of the thin-wall workpiece, and the processing qualification rate of the internal thread of the thin-wall workpiece is greatly improved.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (4)

1. The utility model provides a positive and negative shredding cone, includes screw thread section (1) for cutting the screw thread, and this screw thread section (1) is provided with cutting groove (3) and a plurality of cutting part (4), its characterized in that, cutting part (4) are provided with cutting rake angle (5) and cutting relief angle (6), cutting rake angle (5) with cutting relief angle (6) all are located with screw thread section (1) axis of rotation is the cutting circle at center, cutting part (4) with distance between the cutting circle is drop (7), drop (7) certainly cutting rake angle (5) to the direction of cutting relief angle (6) increases earlier and then reduces.

2. A positive and negative cutting tap according to claim 1, wherein said drop (7) decreases from said front cutting angle (5) to a position intermediate said front cutting angle (5) and said rear cutting angle (6); the fall (7) increases from the intermediate position between the cutting rake angle (5) and the cutting relief angle (6) to the direction of the cutting relief angle (6).

3. A positive and negative cutting tap according to claim 1, wherein the transition between said front cutting angle (5) and said rear cutting angle (6) is a circular arc transition with the center facing outwards.

4. The positive and negative thread cutting awl according to claim 1, wherein the thread section (1) is provided with four cutting grooves (3), and the cutting grooves (3) are formed in the thread section (1) centering on a rotation axis of the thread section (1).

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