CN210548318U

CN210548318U - Reducing step drill

Info

Publication number: CN210548318U
Application number: CN201921542046.0U
Authority: CN
Inventors: 刘健; 陈刚; 颜晓龙
Original assignee: Suzhou Ahno Precision Cutting Technology Co ltd
Current assignee: Suzhou Ahno Precision Cutting Technology Co ltd
Priority date: 2019-09-17
Filing date: 2019-09-17
Publication date: 2020-05-19
Anticipated expiration: 2029-09-17

Abstract

The utility model relates to a reducing ladder bores, including stalk portion and cutting portion. Wherein the cutting portion includes at least two outer circular edges each extending helically around an outer sidewall of the cutting portion. In the left-right direction, the outer circular blade is composed of a first cutting section and a second cutting section having different cutting diameters. The cutting edge of the outer circular blade is provided with a process groove for smooth transition of the first cutting section and the second cutting section. This results in the first cutting segment in the first drilling pass having a relatively small peripheral rake angle, which in turn results in excellent plunge. In addition, the requirement on the cutting diameter of the second cutting section is relaxed to a certain extent, namely, the core thickness value of the second cutting section is increased, so that the stepped drill has more excellent drilling rigidity, and the forming quality of the aperture of a workpiece is ensured.

Description

Reducing step drill

Technical Field

The utility model belongs to the technical field of the cutting tool makes technique and specifically relates to a reducing ladder bores.

Background

In the actual drilling process, the aperture of part work piece often has little reducing step face, for example car fuel sprayer, and its step face height value only has tens of silks, and has 10 ~ 15 inclination. In addition, since the workpiece is often made of stainless steel, high temperature nickel-based alloy, or the like, the helical angle of the drill needs to be strictly controlled in the preliminary machining stage. When the spiral angle value is larger, the cutting edge for forming the step surface is easy to wear; when the helix angle value is smaller, the forming roughness value of the aperture is lower, and the use requirement can not be met.

In the prior art, step correction or protective knife edges are added as means for solving the problems, so that good effects are achieved. However, there are also serious disadvantages. In the first improvement mode, the radial height of the forming step is extremely small, and the forming step has an inclination angle, so that correction and forming of the drill bit are not convenient. For the second improvement mode, when actually grinding the drill bit, it is difficult to ensure that the protection edge is only repaired at the step diameter-changing position, and the cost of the result is compromised that the protection edge needs to be repaired on the first step at the same time, so that the radial rake angle of the first step becomes smaller and even becomes negative, thereby affecting the forming quality of the workpiece. Thus, a skilled person is urgently needed to solve the above problems.

SUMMERY OF THE UTILITY MODEL

The to-be-solved technical problem of the utility model is to provide a reducing ladder bores that is used for little reducing step face machine-shaping specially, and is convenient for make.

In order to solve the technical problem, the utility model relates to a reducing ladder bores, including stalk portion and cutting portion. Wherein the cutting portion includes at least two outer circular edges each extending helically around an outer sidewall of the cutting portion. In the left-right direction, the outer circular blade is composed of a first cutting section and a second cutting section having different cutting diameters. The cutting edge of the outer circular blade is provided with a process groove for smooth transition of the first cutting section and the second cutting section.

As the technical proposal of the utility model is further improved, the peripheral edge front angle β of the first cutting segment is controlled to be 12-16 degrees, and the peripheral edge front angle beta of the second cutting segment is controlled to be 6-10 degrees.

As the further improvement of the technical proposal of the utility model, the helix angle gamma of the outer circular blade is controlled at 25-42 degrees.

As the technical proposal of the utility model is further improved, the total length of the process groove is controlled to be 1-1.5 mm. The process groove is a reducing arc groove, and the radius of each arc formed by the process groove is controlled to be 20-50 mm.

As the technical scheme of the utility model improve still further, the outer circle sword is until extending to the terminal surface of cutting portion in order to form the end sword, and its trailing angle delta is 10 ~ 18.

As a further improvement of the technical proposal of the utility model, the outer circular blade comprises a false blade which is formed by extending backwards from the cutting edge.

As the technical scheme of the utility model the further improvement, the width w of false blade is controlled at 0.2 ~ 0.5mm, and the control of false blade relief angle epsilon is at 2 ~ 5.

As a further improvement of the technical solution of the present invention, the outer diameter of the cutting portion is D, the length of the cutting portion is L, and then L is 3 to 5D.

As the technical scheme of the utility model the further improvement, the radial run-out and the axial run-out of cutting portion are all controlled within 0.005.

As the utility model discloses technical scheme's further improvement, the cutting blade of excircle sword is handled through the radius, and its radius of circle R control is at 0.3 ~ 0.5 mm.

Compare in the drilling cutter of traditional project organization the utility model discloses an among the technical scheme, the excircle sword is formed by first cutting section and second cutting section smooth transition to make the first cutting section that is in at first going into the drilling process have relatively less week sword anterior angle, and then make it have good incisional nature. In addition, the requirement on the cutting diameter of the second cutting section is relaxed to a certain extent, namely, the core thickness value of the second cutting section is increased, so that the stepped drill has more excellent drilling rigidity, and the forming quality of the aperture of a workpiece is ensured.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic structural diagram of the middle variable-diameter stepped drill of the present invention.

Fig. 2 is an enlarged view of a portion I of fig. 1.

Fig. 3 is a left side view of fig. 1.

3 fig. 3 4 3 is 3 a 3 sectional 3 view 3 a 3- 3 a 3 of 3 fig. 3 1 3. 3

Fig. 5 is a partial enlarged view II of fig. 4.

Fig. 6 is a partial section view of the outer circular blade in the variable diameter stepped drill of the present invention.

FIG. 7 is a partial sectional view of the end blade of the variable-diameter stepped drill of the present invention

1-a handle; 2-a cutting section; 21-outer circular edge; 211 — a first cutting segment; 212-a second cutting segment; 213-process groove; 214-a false margin; 22-end edge.

Detailed Description

In the description of the present invention, it should be understood that the terms "left", "right", "front", "back", 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 simplicity of description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and thus should not be construed as limiting the present invention.

The present invention will be described in detail with reference to the following embodiments, and fig. 1 shows a schematic structural diagram of a middle variable diameter stepped drill of the present invention, which includes a shank portion 1 and a cutting portion 2. Wherein the cutting part 2 comprises two outer circular edges 21, each extending helically around the outer side wall of the cutting part 2. In the left-right direction, the outer cutting edge 21 is constituted by a first cutting section 211 and a second cutting section 212 having different cutting diameters. A process groove 213 is formed on the cutting edge of the outer circular blade 21 to smoothly transition the first cutting segment 211 and the second cutting segment 212 (as shown in fig. 2). This results in the first cutting segment 211 having a relatively low peripheral rake angle during the first drilling pass, which results in excellent plunge performance. In addition, the requirement on the cutting diameter of the second cutting section 212 is relaxed to a certain extent, namely, the core thickness value of the second cutting section 212 is increased, so that the variable-diameter stepped drill has more excellent drilling rigidity, and the forming quality of the aperture of a workpiece is ensured.

Here, the number of the outer cutting edges 21 may be set to two as described above, and three, four, five, or the like may be selected according to actual conditions. Generally, as the number of the outer circular blades 21 increases, the forming process of the hole diameter of the workpiece becomes more stable.

as a further optimization of the above-described variable diameter step drill structure, it is preferable that the peripheral edge rake angle α of the first cutting segment 211 is controlled to 12 to 16 °, and the peripheral edge rake angle β of the second cutting segment 212 is controlled to 6 to 10 ° (as shown in fig. 4 and 5), so that smooth transition can be ensured as much as possible while ensuring the cutting rigidity of the outer circular edge 21, and the actual cutting force can be reduced to a certain extent, thereby reducing the cutting energy consumption and the amount of deformation of the variable diameter step drill itself during cutting, and improving the forming accuracy.

In order to improve the smooth transition of the first cutting segment 211 relative to the second cutting segment 212 and reduce the difficulty of machining and forming, the total length of the process groove 213 may be controlled to be 1-1.5 mm. In addition, the process groove 213 is required to be a reducing arc groove, and the radius of each arc is controlled to be 20-50 mm.

As known, the spiral angle is the included angle between the spiral line of the excircle of the variable-diameter step drill and the axis of the variable-diameter step drill after the spiral line is unfolded into a straight line. Generally, as the helix angle increases, the rake angle of the outer cutting edge 21 increases accordingly, thereby increasing the smoothness of chip discharge to some extent, however, the rigidity of the variable-diameter step drill decreases. Therefore, in consideration of both chip removal performance and cutting rigidity, the helix angle γ of the variable-diameter stepped drill is preferably controlled to be 25-42 ° (as shown in fig. 1).

Further, in order to further improve the axial cutting performance of the variable diameter step drill, an end cutting edge 22 (shown in fig. 1 and 3) may be provided at an end of the cutting portion 2, which is formed by extending the outer circular cutting edge 21 leftward along the cutting portion 2 and has a back angle δ of 10 to 18 ° (shown in fig. 7).

Moreover, a false blade 214 can be formed on the outer circular blade 21 and is formed by extending the cutting edge backwards (as shown in fig. 6), so that continuous grinding of the outer circular blade 21 and the end blade 22 is facilitated, formation of a blank groove is avoided, accuracy of a forming size is greatly improved, and in addition, by adopting the technical scheme for setting, reduction of roughness of parts is facilitated, and machining accuracy is improved. As proved by a lot of experimental data, generally speaking, the width w of the dummy blade 214 is preferably controlled to be 0.2-0.5 mm, and the clearance angle ε of the dummy blade 214 is preferably controlled to be 2-5 ° (as shown in FIG. 6).

Further, in order to further improve the machining accuracy of the variable diameter step drill and the roughness of the workpiece forming surface, it is also possible to control the total radial run-out and the total axial run-out of the cutting portion 2 to be within 0.005, and it is preferable to perform the machining by the electric discharge method.

In addition, in order to improve the strength of the variable-diameter stepped drill during high-speed cutting of a workpiece and improve the service life of the variable-diameter stepped drill, as a further optimization of the structure, the axial-to-radial ratio of the cutting portion 2 may be defined, and the following is specifically recommended: assuming that the length of the cutting portion 2 is L, L is 3 to 5D, where D represents the outer diameter of the cutting portion 2.

Moreover, the edge of the outer circular blade 21 can be rounded, and the radius R is controlled to be 0.3-0.5 mm (as shown in fig. 6), so that the stress state of the outer circular blade 21 in the cutting process can be effectively optimized, and the blade breakage phenomenon can be prevented.

In view of the smoothness of chip removal, it is necessary to control the ratio of the core thickness to the cutting portion 2, and the outer diameter of the cutting portion 2 is set to D, and the core thickness diameter is set to D, which is generally 50 to 55% D.

Finally, the cutting part 2 can be provided with a plurality of cutting edges for improving the abrasion resistance of the reducing step drill, prolonging the sharpening period of the reducing step drill and the likeIs provided with a wear-resistant coating (not shown in the figure), and preferably selects TiC, TiN and Al according to the material of the preprocessed workpiece₂O₃Or a composite coating.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A reducing step drill comprises a handle part and a cutting part; wherein the cutting portion includes at least two outer circular edges each extending helically around an outer sidewall of the cutting portion; the outer circular edge is composed of a first cutting section and a second cutting section with different cutting diameters along the left-right direction; and a process groove is formed on the cutting edge of the outer circular blade and used for smoothly transiting the first cutting section and the second cutting section.

2. the variable-diameter stepped drill according to claim 1, wherein the peripheral edge rake angle α of the first cutting segment is controlled to be 12 to 16 °, and the peripheral edge rake angle β of the second cutting segment is controlled to be 6 to 10 °.

3. The variable diameter stepped drill according to claim 1, wherein a helix angle γ of the outer circular edge is controlled to be 25 to 42 °.

4. The variable-diameter stepped drill according to any one of claims 1 to 3, wherein the total length of the process groove is controlled to be 1-1.5 mm; the process groove is a reducing arc groove, and the radius of each arc formed by the process groove is controlled to be 20-50 mm.

5. The variable diameter stepped drill according to claim 4, wherein the outer circular edge extends up to an end face of the cutting portion to form an end edge, and a trailing angle δ thereof is 10 to 18 °.

6. The variable diameter stepped drill according to claim 4, wherein the outer circular edge comprises a false margin extending rearwardly from the cutting edge thereof.

7. The variable diameter stepped drill according to claim 6, wherein the width w of the dummy land is controlled to be 0.2 to 0.5mm, and the dummy land relief angle ε is controlled to be 2 to 5 °.

8. The variable-diameter stepped drill according to claim 4, wherein the cutting portion has an outer diameter D, and the length L of the cutting portion is 3-5D.

9. The variable diameter stepped drill according to claim 4, wherein the full radial run-out and the full axial run-out of the cutting portion are controlled to be within 0.005.

10. The variable diameter stepped drill according to claim 4, wherein the cutting edge of the outer circular edge is rounded and the radius R of the circle is controlled to be 0.3-0.5 mm.