Internal hole spiral broach

Abstract

The utility model discloses a kind of inner hole helical broach, including gradually variable taper tool body, shallow chip flute, double circular arc cutter tooth, thread cooling channel, through-hole, connecting section and deep chip flute;The shallow chip flute and deep chip flute are opened on the outer wall of gradually variable taper tool body, gradually variable taper tool body is provided with gradually variable thread on outer wall, double circular arc cutter tooth is set on gradually variable thread;The utility model is with structured design, the gradually variable taper tool body of the device is contacted with helical inner hole by diameter gradually variable design, cutting force is greatly dispersed, effectively suppresses processing vibration, ensure the consistency precision of helical surface, the differentiating design of deep shallow chip flute, according to chip quantity self-adapting adjustment chip space of roughing and finishing stage, accommodate a large amount of chip when roughing through deep groove, avoid accumulation, ensure cutting stability when finishing through shallow groove, reduce the interference to machined surface, significantly improve the smoothness of chip removal and surface quality.

Description

Technical Field

[0001] This utility model relates to the field of spiral broaching technology, and in particular to an internal spiral broaching tool. Background Technology

[0002] In the field of machining, the machining of internal helical surfaces often relies on internal helical broaches. However, their performance is limited by traditional structures and suffers from many defects. Firstly, there is a contradiction between machining accuracy and efficiency. Traditional straight-tube broaches have line contact with the helical inner hole, and during high-speed cutting, uneven force causes periodic vibrations, resulting in waviness on the machined surface. The surface roughness can only be maintained above Ra 1.6μm, and the helix angle error is large, failing to meet the assembly requirements of precision parts. Secondly, the chip removal system uses a uniform groove design, which easily leads to chip accumulation and edge formation during roughing, causing more than 30% of workpieces to be scrapped due to scratches. Furthermore, during finishing, the groove is too deep... Firstly, the high-speed steel cutting tool suffers from several problems. Firstly, the machining stability is severely compromised, reducing production efficiency by 40%. Secondly, the cutting edges are often single-circular or right-angle transitions, resulting in a stress concentration factor as high as 3.5 when machining high-strength alloys such as 40CrNiMoA, and a chipping rate exceeding 35%. Thirdly, the linear cooling system is poorly matched to the spirally distributed cutting teeth, leading to cutting zone temperatures often reaching 800 to 1000 degrees Celsius. This causes the hardness of the high-speed steel cutting teeth to drop from 62 HRC to below 55 HRC, doubling the thermal wear rate. Furthermore, the lack of a reference positioning in the clamping structure further exacerbates tool wear, limiting its application in deep hole and complex spiral surface machining. Utility Model Content

[0003] The purpose of this invention is to provide an internal spiral broach to solve the problems mentioned in the background art.

[0004] To solve the above-mentioned technical problems, this utility model provides the following technical solution: an internal spiral broach, comprising a tapered broach body, wherein a shallow chip removal groove and a deep chip removal groove are provided on the outer wall of the tapered broach body, and a tapered thread is provided on the outer wall of the tapered broach body, wherein double arc broach teeth are provided on the tapered thread, wherein a large arc is provided at the front end of the double arc broach teeth, and a small arc is provided at the rear end of the double arc broach teeth.

[0005] As a further technical solution of this utility model, the tapered cutter body is provided with a threaded cooling channel, the end of the tapered cutter body is provided with a through hole, and the front end of the tapered cutter body is provided with an outlet.

[0006] As a further technical solution of this utility model, the end of the gradient conical cutter body is provided with a connecting section, a reference ring is fixedly connected to the connecting section, a rear shank is fixedly connected to one side of the outer surface of the reference ring, and a positioning ring is provided at the end of the rear shank.

[0007] As a further technical solution of this utility model, a straight cooling channel is provided in the connecting section, the reference ring, the rear handle and the positioning ring.

[0008] As a further technical solution of this utility model, a clamping groove is provided on the outer wall of the reference ring, and a hollow groove is provided on the outer wall of the rear handle.

[0009] As a further technical solution of this utility model, a tool relief groove is provided on the outer wall of the positioning ring.

[0010] As a further technical solution of this utility model, a fastening ring is provided on one outer surface of the positioning ring, and a sealing ring is provided on the other outer surface of the positioning ring.

[0011] Compared with the prior art, the beneficial effects achieved by this utility model are as follows: This utility model adopts a structured design. The tapered cutter body of this device, through its tapered diameter design, forms surface contact with the spiral inner hole, significantly dispersing the cutting force, effectively suppressing machining vibration, and ensuring the consistent accuracy of the spiral surface. The differentiated design of the deep and shallow chip removal grooves can adaptively adjust the chip space according to the amount of chips in the roughing and finishing stages. During roughing, the deep grooves accommodate a large amount of chips, preventing accumulation, while during finishing, the shallow grooves ensure cutting stability, reduce interference with the machined surface, and significantly improve chip removal smoothness and surface quality. Furthermore, the device's double arc... The cutting teeth utilize a small arc at the front end to ensure cutting sharpness, while a large arc at the rear end disperses edge stress, preventing edge chipping during cutting of hard and brittle materials and extending tool life. The composite cooling channel extends along the spiral trajectory of the tool body, precisely covering all cutting areas and promptly dissipating cutting heat, reducing the impact of thermal wear on the cutting tooth performance. In the clamping and positioning structure, the reference ring and positioning ring ensure the relative positional accuracy between the tool and the machine tool. The clamping groove and retraction groove facilitate quick clamping and smooth tool retraction. The sealing ring and fastening ring improve the sealing performance of the cooling system, making it adaptable to internal hole machining and deep hole scenarios with various spiral parameters, significantly improving its versatility and practicality. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a three-dimensional structural diagram of the present invention;

[0014] Figure 2 for Figure 1 Enlarged structural diagram of region A in the middle;

[0015] Figure 3 This is a cross-sectional three-dimensional structural diagram of the present invention.

[0016] In the diagram: 1. Gradient tapered cutter body; 2. Shallow chip removal groove; 3. Gradient thread; 4. Double circular arc cutter teeth; 5. Threaded cooling channel; 6. Through hole; 7. Exit; 8. Connecting section; 9. Reference ring; 10. Clamping groove; 11. Rear shank; 12. Empty groove; 13. Positioning ring; 14. Retraction groove; 15. Straight cooling channel; 16. Large circular arc; 17. Small circular arc; 18. Sealing ring; 19. Fastening ring; 20. Deep chip removal groove. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0018] Please see the appendix Figure 1 -Appendix Figure 3This utility model provides an embodiment of an internal spiral broach, comprising a tapered broach body 1, with shallow chip removal grooves 2 and deep chip removal grooves 20 on the outer wall of the tapered broach body 1, tapered threads 3 on the outer wall of the tapered broach body 1, and double arc cutting teeth 4 on the tapered threads 3. The front end of the double arc cutting teeth 4 is provided with a large arc 16, and the rear end of the double arc cutting teeth 4 is provided with a small arc 17. A threaded cooling channel 5 is provided inside the tapered broach body 1, a through hole 6 is provided at the end of the tapered broach body 1, and a through hole 6 is provided at the front end of the tapered broach body 1. The tool has an outlet 7. One end of the threaded cooling channel 5 is connected to the through hole 6, and the other end extends to the front end of the tapered cutter body 1 and is connected to the outlet 7, forming a cooling passage that runs through the cutter body. This allows the coolant to be transported from the end of the cutter body to the front cutting area. The end of the tapered cutter body 1 is provided with a connecting section 8, and a reference ring 9 is fixedly connected to the connecting section 8. A rear shank 11 is fixedly connected to one side of the outer surface of the reference ring 9. A positioning ring 13 is provided at the end of the rear shank 11. The connecting section 8, the reference ring 9, the rear shank 11, and the positioning ring 13 are coaxially arranged, forming the rear end support and positioning mechanism of the tool. The positioning components ensure the overall structural rigidity and clamping accuracy of the tool. Direct cooling channels 15 are provided within the connecting section 8, reference ring 9, rear shank 11, and positioning ring 13. These channels sequentially pass through the connecting section 8, reference ring 9, rear shank 11, and positioning ring 13, and communicate with the through hole 6 at the end of the tapered tool body 1, forming a channel for coolant to enter the tool body from the rear end. A clamping groove 10 is provided on the outer wall of the reference ring 9, and a slot 12 is provided on the outer wall of the rear shank 11. The clamping groove 10 is used to cooperate with the machine tool clamping mechanism to fix the tool. 2. The shank 11 is used to reduce its weight and provide temporary space for coolant or chips to flow. The outer wall of the positioning ring 13 is provided with a tool retraction groove 14, which provides clearance space for the tool to exit after machining and avoids interference between the tool and the workpiece. A fastening ring 19 is provided on one outer surface of the positioning ring 13 and a sealing ring 18 is provided on the other outer surface of the positioning ring 13. The fastening ring 19 is used to enhance the tightness of the connection between the positioning ring 13 and the machine tool, and the sealing ring 18 is used to prevent coolant leakage in the cooling channel and ensure the sealing of the cooling system.

[0019] Working Principle: Using this invention, the connecting section 8 at the end of the tapered cutter body 1 is first fixed to the machine tool via the clamping groove 10 of the reference ring 9. The positioning ring 13 ensures the coaxiality of the tool and the workpiece. A fastening ring 19 on one side of the positioning ring 13 enhances clamping stability, while a sealing ring 18 on the other side ensures the sealing of the cooling system, preventing coolant leakage. The machine tool drives the tool to rotate and feed axially. The tapered thread 3 on the outer wall of the tapered cutter body 1 drives the double-arc cutting teeth 4 to cut into the inner hole of the workpiece. The small arc 17 at the rear end of the double-arc cutting teeth 4 directly contacts the workpiece material, achieving precise cutting with a sharp cutting edge. The large arc 16 at the front end disperses cutting stress, preventing edge chipping and guiding the chips towards the chip removal groove. The tapered cutter body 1's diameter gradually increases with the increase of the feed rate, gradually expanding the inner hole size, ultimately forming a spiral inner hole that meets the precision requirements. The large amount of cutting material generated during rough machining... Chips are discharged through the deep chip removal groove 20, while fine chips from finishing are discharged through the shallow chip removal groove 2. The differentiated design of the deep and shallow grooves adapts to the chip removal requirements of different cutting stages, preventing chip accumulation and scratching of the machined surface. Coolant enters from the locating ring 13, the back shank 11, the reference ring 9, and the connecting section 8 through the straight cooling channel 15, flows into the thread cooling channel 5 through the through hole 6 at the end of the tapered cutter body 1, is transported along the spiral trajectory to the front end of the cutter body, and finally reaches the cutting area of ​​the double circular arc cutter teeth 4 through the outlet 7, reducing the cutting temperature in real time and reducing tool wear. After machining, the tool retracts in the opposite direction along the axial direction. The empty groove 12 can reduce the amount of material used and reduce the weight of the tool without weakening the strength of the core load-bearing part of the back shank 11. The tool retraction groove 14 on the outer wall of the locating ring 13 provides clearance space for the tool retraction process, avoids interference between the tool and the workpiece, and ensures a smooth and damage-free retraction process.

[0020] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0021] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0022] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. An internal spiral broach, comprising a tapered broach body (1), characterized in that: The outer wall of the tapered cutter body (1) is provided with a shallow chip removal groove (2) and a deep chip removal groove (20). The outer wall of the tapered cutter body (1) is provided with a tapered thread (3). The tapered thread (3) is provided with a double arc cutter tooth (4). The front end of the double arc cutter tooth (4) is provided with a large arc (16), and the rear end of the double arc cutter tooth (4) is provided with a small arc (17).

2. The internal spiral broach according to claim 1, characterized in that: The tapered cutter body (1) has a threaded cooling channel (5) inside, a through hole (6) at the end of the tapered cutter body (1), and an outlet (7) at the front end of the tapered cutter body (1).

3. The internal spiral broach according to claim 2, characterized in that: The end of the tapered cutter body (1) is provided with a connecting section (8), and a reference ring (9) is fixedly connected to the connecting section (8). A rear shank (11) is fixedly connected to one side of the outer surface of the reference ring (9), and a positioning ring (13) is provided at the end of the rear shank (11).

4. The internal spiral broach according to claim 3, characterized in that: The connecting section (8), the reference ring (9), the rear handle (11), and the positioning ring (13) are all provided with direct cooling channels (15).

5. The internal spiral broach according to claim 4, characterized in that: The outer wall of the reference ring (9) is provided with a clamping groove (10), and the outer wall of the rear handle (11) is provided with a hollow groove (12).

6. The internal spiral broach according to claim 4, characterized in that: The outer wall of the positioning ring (13) is provided with a tool relief groove (14).

7. The internal spiral broach according to claim 6, characterized in that: A fastening ring (19) is provided on one outer surface of the positioning ring (13), and a sealing ring (18) is provided on the other outer surface of the positioning ring (13).

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