CN114769749B - Durable tap with stepped tooth shape - Google Patents
Durable tap with stepped tooth shape Download PDFInfo
- Publication number
- CN114769749B CN114769749B CN202210586083.1A CN202210586083A CN114769749B CN 114769749 B CN114769749 B CN 114769749B CN 202210586083 A CN202210586083 A CN 202210586083A CN 114769749 B CN114769749 B CN 114769749B
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- cutting
- tooth
- cutting tooth
- teeth
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- 230000036346 tooth eruption Effects 0.000 claims abstract description 46
- 230000002035 prolonged effect Effects 0.000 abstract description 9
- 238000003754 machining Methods 0.000 abstract description 8
- 238000002474 experimental method Methods 0.000 abstract description 6
- 238000000034 method Methods 0.000 description 6
- 230000008569 process Effects 0.000 description 6
- 239000011295 pitch Substances 0.000 description 4
- 238000005299 abrasion Methods 0.000 description 3
- 238000005553 drilling Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 210000004210 tooth component Anatomy 0.000 description 2
- 229910000851 Alloy steel Inorganic materials 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 230000008092 positive effect Effects 0.000 description 1
- 230000008521 reorganization Effects 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23G—THREAD CUTTING; WORKING OF SCREWS, BOLT HEADS, OR NUTS, IN CONJUNCTION THEREWITH
- B23G5/00—Thread-cutting tools; Die-heads
- B23G5/02—Thread-cutting tools; Die-heads without means for adjustment
- B23G5/06—Taps
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Milling Processes (AREA)
Abstract
The invention relates to a durable tap with a stepped tooth shape, wherein one tooth at the lowest end of a tap head is a screwing tooth, a cutting tooth section is arranged above the screwing tooth, the cutting tooth section comprises a plurality of cutting tooth groups which are adjacently arranged, and each cutting tooth group comprises at least one cutting tooth; the cutting cone angle of the cutting teeth in the upper cutting tooth set is larger than the cutting cone angle of the cutting teeth in the lower cutting tooth set. In the invention, the stress of each cutting tooth group is gradually reduced, and when one cutting tooth group below is excessively worn or one cutting tooth in one cutting tooth group is excessively worn, the machining of the cutting teeth in other cutting tooth groups above to the threaded holes is not influenced, so that the service life of the tap is prolonged, and the service life of the tap can be prolonged by three times maximally through experiments.
Description
Technical Field
The invention belongs to the technical field of screw tap structure improvement, and particularly relates to a durable screw tap with stepped tooth shapes.
Background
The screw tap includes tap head 5 and taper shank 6, and the tap head can set up straight flute and the spiral groove that is used for the chip removal, and straight flute tap can process the through-hole, and the spiral flute tap can process the blind hole, whichever flute profile's screw tap, its profile of tooth distribution is: the cutting tooth section comprises a plurality of cutting teeth with certain cutting widths and relief angles, and is mainly used for forming threaded holes, and the tooth shape of the calibration tooth section is complete and is mainly used for calibrating and polishing thread profiles. The cutting tooth section has the shape characteristics that: when the screw tap is used, the threaded holes are machined and molded gradually along with the expansion of the pitch diameter of the screw tap, and then the tooth segments are calibrated. In the structure, as the cutting cone angles of all the teeth in the cutting tooth sections are the same and the diameters are different, in the cutting machining process, all the cutting teeth are subjected to the same external force, so that the abrasion of all the cutting teeth in the cutting tooth sections is approximately the same, a tap needs to be replaced once the abrasion of part of the cutting teeth occurs, the tap can not continue to machine a threaded hole and can only be scrapped, and the use cost of a manufacturer can be increased.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a durable tap with a stepped tooth shape. In the tap, the screwing teeth are utilized to be screwed into a hole to be machined rapidly, the machining of the threaded hole is performed by utilizing the steps of a plurality of cutting teeth, the cutting cone angle of each cutting tooth group is gradually reduced, the rear angle of the cutting tooth of each cutting tooth group is gradually increased, through the mutual matching of the structures, the stress of each cutting tooth group is gradually reduced, and when a certain cutting tooth group below is excessively worn or a certain cutting tooth in one cutting tooth group is excessively worn, the machining of the cutting tooth in other cutting tooth groups above to the threaded hole is not influenced, so that the service life of the tap is prolonged, and through experiments, the service life of the tap can be prolonged by three times at most.
The technical scheme adopted by the invention is as follows:
a durable screw tap of ladder profile of tooth sets up cutting tooth section on the screw tap head, its characterized in that: one tooth at the lowest end of the tap head is a screwing tooth, a cutting tooth section is arranged above the screwing tooth, the cutting tooth section comprises a plurality of cutting tooth groups which are adjacently arranged, and each cutting tooth group comprises at least one cutting tooth;
the cutting cone angle of the cutting teeth in the upper cutting tooth set is smaller than the cutting cone angle of the cutting teeth in the lower cutting tooth set.
Further: each cutting tooth group comprises at least two cutting teeth.
Further: the cutting cone angles of all the cutting teeth in each cutting tooth set are the same.
Further: the cutting cone angle of each cutting tooth set is equal to the difference between the cutting cone angle of the adjacent cutting tooth set below the cutting cone angle and the average value of the cutting cone angles.
Further: the cutting cone angle average value is equal to the cutting cone angle of the lowermost cutting tooth group divided by the number of cutting tooth groups.
Further: the relief angle of all cutting teeth in the upper cutting tooth set is greater than the relief angle of all cutting teeth in the lower cutting tooth set.
Further: the relief angle of all cutting teeth in each cutting tooth set is the same.
Further: the number of the cutting tooth groups is 2-4.
Further: the cutting cone angle of the screwing teeth is 28-32 degrees.
The invention has the advantages and positive effects that:
According to the screw tap, the screwing teeth can be screwed into a hole to be machined rapidly, the machining of the threaded hole is performed by utilizing the steps of multiple cutting tooth components, the cutting taper angle of each cutting tooth group is gradually reduced, the rear angle of the cutting tooth of each cutting tooth group is gradually increased, through the mutual matching of the structures, the stress of each cutting tooth group is gradually reduced, and when one cutting tooth group below is excessively worn or one cutting tooth in one cutting tooth group is excessively worn, the machining of the cutting tooth in the other cutting tooth group above to the threaded hole is not affected, so that the service life of the screw tap is prolonged, and through experiments, the service life of the screw tap can be prolonged by three times at most.
Drawings
FIG. 1 is a schematic diagram of the structure of the present invention;
FIG. 2 is a schematic illustration of the variation of the cutting cone angle of the two cutter sets of FIG. 1;
Fig. 3 (a), (b) and (c) are radial sectional views of the teeth of the two cutting tooth sets.
Detailed Description
The invention will now be further illustrated by reference to the following examples, which are intended to be illustrative, not limiting, and are not intended to limit the scope of the invention.
As shown in the figure, the durable tap with stepped tooth form is provided with cutting tooth segments on the tap head 5, and the innovation of the invention is that: one tooth at the lowest end of the tap head is a screwing tooth 1, a cutting tooth section is arranged above the screwing tooth, the cutting tooth section comprises a plurality of cutting tooth groups which are adjacently arranged, each cutting tooth group comprises at least one cutting tooth, and a calibration tooth section is arranged above the cutting tooth section.
The cutting cone angle of the cutting teeth in the upper cutting tooth set is smaller than the cutting cone angle of the cutting teeth in the lower cutting tooth set. Each cutting tooth group comprises at least two cutting teeth. The cutting cone angles of all the cutting teeth in each cutting tooth set are the same.
The cutting cone angle of each cutting tooth set is equal to the difference between the cutting cone angle of the adjacent cutting tooth set below the cutting cone angle and the average value of the cutting cone angles. The cutting cone angle average value is equal to the cutting cone angle of the lowermost cutting tooth group divided by the number of cutting tooth groups.
The relief angle of all cutting teeth in the upper cutting tooth set is greater than the relief angle of all cutting teeth in the lower cutting tooth set. The relief angle of all cutting teeth in each cutting tooth set is the same.
The number of the cutting tooth groups is 2-4. The cutting cone angle of the screwing teeth is 28-32 degrees.
The chip groove of the tap may have a straight groove or a spiral groove, and the following description of each structure is given by the straight groove structure: as shown in fig. 1, 2 and 3, the cutting teeth are a group A and a group B, and the thread pitches and other parameters inside the group A and the group B, between the group A and the group B and the screwing teeth are processed according to national standards. The screwing teeth are used for guiding the tap head, have no rear angle, and can enable the tap head to quickly enter the hole of the standby machine when the tap head is fed, so that the subsequent cutting section can process threads on the inner wall of the hole. Of course, it is also possible for the screw-on teeth to have a smaller relief angle, so that small-sized cuts can be made.
The included angle between the generatrix of the teeth and the tap head axis is the cutting cone angle, such as the cutting cone angles alpha, beta, gamma in figure 2.
The total of five cutting teeth are needed for the cutting tooth segments according to the parameters of the holes to be machined, two adjacent to the screwing teeth 1 are arranged as a cutting group A, and three adjacent to the calibration tooth segments C are arranged as a cutting group B.
The parameters of the cutting cone angle are as follows:
1. And (3) screwing teeth: the cutting cone angle α is preferably 30 degrees;
2. cutting teeth group A, cutting cone angle beta is 8-10 degrees, preferably 8 degrees;
3. Cutting tooth set B: the cutting cone angle γ is 4 degrees.
As shown in fig. 3, the relief angle of all the cutting teeth 2 in the cutting group a is θ1, and the relief angle of all the cutting teeth 3 in the cutting group B is θ2, with θ1 being smaller than θ2.
The increase in pitch diameter of the plurality of cutting teeth also increases gradually as a result of the product thread data divided by the number of cutting teeth.
When the number of the cutting teeth is three, two cutting teeth are arranged in each cutting tooth group. The cutting cone angle beta of the first cutting tooth group close to the screwing tooth is 9 degrees, the average value is 9/3=3, the cutting cone angle gamma of the second cutting tooth group gamma above is 9-3=6 degrees, and the cutting cone angle delta of the third cutting tooth group delta close to the uppermost of the calibration tooth sections is 6-3=3 degrees. The relief angle of the cutting teeth of the first cutting tooth set, the second cutting tooth set, and the third cutting tooth set increases at a time.
When the number of the cutting teeth is four, the arrangement of the cutting cone angle and the relief angle is also designed according to the rule.
The use process of the invention is described with the structure of fig. 1:
The tap head is fed into the hole rapidly through the guiding action of the screwing teeth.
Cutting is carried out by the first cutting teeth of the first cutting tooth group, and the second cutting teeth are subjected to second cutting because of the increase of the pitch diameter;
And the second cutting tooth group enters the hole to continuously cut the shallow thread machined in advance, and the sequence is that the first cutting tooth to the third cutting tooth in the reorganization are sequentially subjected to expanding cutting.
When the third cutting tooth of the second cutting tooth set enters the hole, the processing of the threads passing through the second cutting tooth set is actually completed, and the subsequent calibration tooth segments perform the calibration of the threads.
After calibration, the tap head is withdrawn from the threaded hole.
From the above process, the stress process of the tap during cutting is as follows: the screwing teeth without back angle are guided to enter, and the external force is minimum. The cutting cone angles of all the cutting teeth of the first cutting tooth group to the second cutting tooth group become smaller gradually, which means that the cutting amount becomes smaller gradually, so that the stress becomes smaller gradually. The slower the wear of the cutting teeth is, the closer the calibration tooth segments are, whereas the same prior art arrangement of cutting cone angles results in simultaneous wear of all the cutting teeth.
When the cutting ability of a certain cutting tooth below is reduced due to abrasion, the stress of the adjacent cutting tooth above is increased, and the diameter expansion cutting can be continued, so that the service life of the tap is greatly prolonged.
Such as: when a threaded hole of a certain alloy steel part is machined, two groups of taps with the same material are subjected to drilling experiments, 10 taps with the same traditional cutting cone angles are used in a comparison group, five cutting teeth are used in a comparison group, five calibration teeth are used in a comparison group, and the structures shown in figures 1, 2 and 3 are used in an experiment group. The tap materials are the same, the same grinding wheel mill and cooling oil are used for processing, and parameters such as the rotating speed and the flow speed are the same during processing. Through testing, the average drilling number of the screw taps of the invention is three times that of the control group.
According to the screw tap, the screwing teeth can be screwed into a hole to be machined rapidly, the machining of the threaded hole is performed by utilizing the steps of multiple cutting tooth components, the cutting taper angle of each cutting tooth group is gradually reduced, the rear angle of the cutting tooth of each cutting tooth group is gradually increased, through the mutual matching of the structures, the stress of each cutting tooth group is gradually reduced, and when one cutting tooth group below is excessively worn or one cutting tooth in one cutting tooth group is excessively worn, the machining of the cutting tooth in the other cutting tooth group above to the threaded hole is not affected, so that the service life of the screw tap is prolonged, and through experiments, the service life of the screw tap can be prolonged by three times at most.
Claims (4)
1. A durable screw tap of ladder profile of tooth sets up cutting tooth section on the screw tap head, its characterized in that: one tooth at the lowest end of the tap head is a screwing tooth, a cutting tooth section is arranged above the screwing tooth, the cutting tooth section comprises a plurality of cutting tooth groups which are adjacently arranged, and each cutting tooth group comprises at least one cutting tooth;
the cutting cone angle of the cutting teeth in the upper cutting tooth group is smaller than that of the cutting teeth in the lower cutting tooth group;
Each cutting tooth group comprises at least two cutting teeth;
the cutting cone angles of all the cutting teeth in each cutting tooth group are the same;
The cutting cone angle of each cutting tooth group is equal to the difference between the cutting cone angle of the adjacent cutting tooth group below the cutting tooth group and the average value of the cutting cone angles;
the average value of the cutting cone angles is equal to the cutting cone angle of the lowest cutting tooth group divided by the number of the cutting tooth groups;
The relief angle of all cutting teeth in the upper cutting tooth set is greater than the relief angle of all cutting teeth in the lower cutting tooth set.
2. The stepped tooth durable tap according to claim 1 wherein: the relief angle of all cutting teeth in each cutting tooth set is the same.
3. The stepped tooth durable tap according to claim 1 or 2, wherein: the number of the cutting tooth groups is 2-4.
4. The stepped tooth durable tap according to claim 1 or 2, wherein: the cutting cone angle of the screwing teeth is 28-32 degrees.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210586083.1A CN114769749B (en) | 2022-05-27 | 2022-05-27 | Durable tap with stepped tooth shape |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210586083.1A CN114769749B (en) | 2022-05-27 | 2022-05-27 | Durable tap with stepped tooth shape |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114769749A CN114769749A (en) | 2022-07-22 |
| CN114769749B true CN114769749B (en) | 2024-07-30 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210586083.1A Active CN114769749B (en) | 2022-05-27 | 2022-05-27 | Durable tap with stepped tooth shape |
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| Country | Link |
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| CN (1) | CN114769749B (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101549422A (en) * | 2009-05-14 | 2009-10-07 | 沈阳飞机工业（集团）有限公司 | Special screw tap for machining titanium alloy |
| CN218362550U (en) * | 2022-05-27 | 2023-01-24 | 天津鸿生科技有限公司 | Stepped tooth-shaped straight-groove screw tap |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201279637Y (en) * | 2008-10-30 | 2009-07-29 | 四川天虎工具有限责任公司 | Forked square screw broaching tap |
| CN201350534Y (en) * | 2009-02-13 | 2009-11-25 | 上海申利螺纹工具有限公司 | Trapezoidal thread tap adopting stepped cutting |
| RU2505383C1 (en) * | 2012-08-09 | 2014-01-27 | Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования "Государственный университет - учебно-научно-производственный комплекс" (ФГБОУ ВПО "Госуниверситет-УНПК") | Device for internal thread cutting |
| CN107803562A (en) * | 2017-12-19 | 2018-03-16 | 兰州理工大学 | Single Zhi Shouyong reason heart screw taps and application method |
| CN108856917B (en) * | 2018-08-20 | 2024-01-09 | 圆兴(厦门)精密工具有限公司 | Screw tap |
| CN210524048U (en) * | 2019-06-20 | 2020-05-15 | 哈尔滨汽轮机厂有限责任公司 | Compound tool for efficiently machining threaded holes |
| CN215034241U (en) * | 2021-04-16 | 2021-12-07 | 河南一工钻业有限公司 | Improved variable helix angle screw tap |
-
2022
- 2022-05-27 CN CN202210586083.1A patent/CN114769749B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101549422A (en) * | 2009-05-14 | 2009-10-07 | 沈阳飞机工业（集团）有限公司 | Special screw tap for machining titanium alloy |
| CN218362550U (en) * | 2022-05-27 | 2023-01-24 | 天津鸿生科技有限公司 | Stepped tooth-shaped straight-groove screw tap |
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| Publication number | Publication date |
|---|---|
| CN114769749A (en) | 2022-07-22 |
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