Special tooth embedded blade broach

Abstract

The utility model discloses a broach with a special tooth embedded blade, which solves the problems that the service life of the existing broach is short due to the fact that the special tooth is easy to abrade in the broaching process to cause meat falling and strain at an outlet, and the existing broach is lack of special structural design in the radial direction and is not capable of improving the performance of individual teeth. The cutter comprises a cylindrical cutter body, a cutter strip groove is formed in the outer wall of the cutter body in the direction parallel to the central axis, a cutter strip is arranged in the cutter strip groove and connected to the cutter body through a bolt, and a plurality of special key grooves are formed in the cutter strip at equal intervals to form special teeth. The cutter further comprises a plurality of rows of spline cutting teeth, each row of spline cutting teeth is arranged on the outer wall of the cutter body, and the two ends of each row of spline cutting teeth are located on the two sides of the corresponding cutter strip groove respectively. A plurality of splines are arranged on each row of spline cutting teeth at equal intervals to form the spline cutting teeth; the broach is an assembly type broach, the blade can be replaced according to the actual use condition, and the economic cost is reduced.

Description

Technical Field

[0001] This utility model relates to broaches, specifically to a broach with a special toothed insert. Background Technology

[0002] In the past two years, with more and more people wearing special teeth (such as...) Figure 1 The image shows the production of a broaching part with a slender 2.5mm trapezoidal groove. The broaching of its internal splines presents increasingly prominent problems: due to the height and narrow width of the special teeth (2.5mm trapezoidal groove), the corresponding broaching tooth root strength is weak, and the stress concentration at the tooth tip is significant. Therefore, during broaching, the 2.5mm trapezoidal groove is prone to wear, resulting in issues such as material loss at the exit and scoring. Sharpening does not improve the situation, leading to a low single-cycle lifespan. Furthermore, the height and narrow width of the special teeth and the weak tooth root strength cause frequent abnormal tooth breakage due to vibration during broaching. This further reduces the overall lifespan of the broach and results in significant material waste for such large tools. Currently, all broaching structures are improved in the axial direction or by combining different materials in the tool body to enhance broach performance. There are no special structural designs in the radial direction, nor are there any performance improvements specifically for individual teeth. Therefore, existing structures cannot effectively address this problem.

[0003] Patent CN103878447A discloses a precision large-scale, modular composite involute internal gear broach, including a broach body on which coarse cutting teeth, fine cutting teeth, and calibration teeth are mounted. The broach sharpening method in this patent is a low-cost, high-efficiency method. The precision large-scale, modular composite involute internal gear broach allows for disassembly and replacement of damaged teeth (unlike traditional broaches where damaged teeth cannot be replaced, leading to tool scrap). Worn teeth can be repeatedly sharpened without affecting product dimensions and precision requirements, thus increasing tool life by more than 15 times compared to domestically produced broaches and more than 5 times compared to imported broaches. In summary, this significantly improves tool life and product quality, reduces processing costs, enhances product market competitiveness, increases enterprise profits, and promotes enterprise development. However, the entire broach in this patent is assembled into disc-shaped inserts, making it impossible to even out the lifespan of each disc-shaped insert, and the broach has high manufacturing costs and is difficult to manufacture.

[0004] Patent CN206169391U discloses an assembled carbide broach, including a tool holder on which multiple inserts are mounted. Each insert has multiple cutting teeth, and the inserts are detachably connected to the tool holder. This broach detachably mounts and fixes the inserts to the tool holder, and the inserts are interchangeable. When the broach reaches the end of its service life or one insert is damaged, the damaged or discarded insert can be removed, a new insert installed, and after adjustment, it becomes a new broach. This means the tool holder can be reused multiple times, reducing the manufacturing and usage costs of the broach. However, this patented broach is for machining keyways and cannot achieve special structural designs in the radial direction or performance improvements for individual teeth. Utility Model Content

[0005] The purpose of this invention is to solve the problems of existing broaches where special teeth are easily worn during broaching, resulting in cutter chipping and scratches at the exit, leading to a short broach life. Furthermore, existing broaches lack special radial structural designs and do not address the performance improvement of individual teeth. This invention provides a broach with a special tooth insert.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A special toothed broach is characterized by comprising a cylindrical broach body and multiple broaches. The outer wall of the broach body has multiple circumferentially oriented grooves parallel to the central axis, and these grooves correspond circumferentially to the special teeth of the internal spline to be machined. The broaches are respectively disposed within these grooves, and each broach has multiple special teeth formed by special keyways at equal intervals. The outer wall of the broach body has multiple rows of spline cutting teeth arranged axially at equal intervals, with each row of spline cutting teeth arranged circumferentially along the outer wall of the broach body.

[0008] The multiple special teeth on the broach bar correspond to the axial positions of multiple rows of spline cutting teeth, which can improve the overall broach life.

[0009] Furthermore, the blade body includes a front shank, a front guide portion, a blade body portion, a rear guide portion, and a rear shank connected in sequence;

[0010] Multiple blade grooves are arranged circumferentially along the outer wall of the blade body;

[0011] The multiple rows of spline cutting teeth are evenly spaced along the axial direction on the outer wall of the tool body.

[0012] Furthermore, the tooth rise of each row of spline cutting teeth is 0.03 mm to 0.05 mm.

[0013] Furthermore, the tooth rise of the special teeth on the blade is 0.02mm to 0.04mm.

[0014] Furthermore, the blade groove is provided with multiple bolt holes, and the blade is connected to the blade groove of the blade body by multiple bolts passing through the multiple bolt holes, which can increase the stability of the overall structure.

[0015] Furthermore, the spacing between two adjacent bolt holes is 175mm~185mm.

[0016] Furthermore, the blade is made of M35 material and the blade body is made of M32 material, which improves the wear resistance of the structure and increases the life of a single broaching pass.

[0017] Furthermore, the length of the blade body is 1780mm~1790mm, and the length of the blade strip is 1120mm~1130mm.

[0018] The beneficial effects of this utility model are:

[0019] (1) This utility model provides a special toothed insert broach that can replace the insert according to the actual use, thereby improving the radial structure and solving the problem that the special teeth of the existing broach are easily worn during the broaching process, resulting in the loss of material at the exit and scratches, which leads to a short broach life.

[0020] (2) This utility model provides a special toothed broach with special teeth that match the spline cutting teeth, thereby improving the overall broach life.

[0021] (3) This utility model provides a special toothed insert broach. The insert is made of M35 material and the body is made of M32 material, which increases its wear resistance and improves the life of a single broaching operation. At the same time, it can also prevent the broach cost from increasing too much (the overall material of the broach increases the price by about 30%, while the insert price increases by about 7%), thereby reducing the cost of a single broaching tool. Attached Figure Description

[0022] Figure 1 This is a cross-sectional view of a broach with irregularly shaped teeth in the background art, perpendicular to its central axis.

[0023] Figure 2 This is a schematic diagram of an embodiment of a special toothed insert broach of the present invention.

[0024] In the figure, 1-tool body; 2-tool bar; 3-spline cutting teeth. Detailed Implementation

[0025] The technical solution of this utility model will be clearly and completely described below with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are only some embodiments of this utility model, and 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.

[0026] like Figure 2 As shown, this embodiment of a special toothed broach includes a cylindrical blade body 1. The outer wall of the blade body 1 has grooves along a direction parallel to the central axis, and multiple grooves correspond to the circumferential positions of the special teeth of the internal spline to be processed. Multiple blades 2 are respectively disposed within the multiple grooves. Multiple threaded holes are equally spaced within the grooves, and multiple bolt holes extending into the grooves are equally spaced on the blades 2. The blades 2 are connected to the grooves of the blade body 1 by multiple bolts 4 passing through the bolt holes. By providing multiple threaded holes, the stability of the connection is increased, facilitating the broaching and grinding of the blades 2.

[0027] In this embodiment, multiple special keyways are equally spaced on the blade 2 to form special teeth. The shape of the special teeth is set according to actual needs. In this embodiment, the special teeth are small trapezoidal grooves with a slender shape and a minimum width of 2.5mm. The blade 2 is detachably connected to the blade body 1 by multiple bolts 4. During use, when the blade 2 is worn, only the blade 2 needs to be replaced, reducing the economic loss caused by replacing the broach.

[0028] In this embodiment, the material used for the cutter bar 2 is M35, and the material used for the cutter body 1 is M32. This increases their wear resistance and improves their single broaching life. At the same time, it also prevents the cost of the broach from increasing too much (the overall material change of the broach increases the price by about 30%, while the price of the insert bar increases by about 7%), thereby reducing the cost of a single broaching tool.

[0029] In this embodiment, multiple rows of spline cutting teeth 3 are equally spaced along the axial direction on the outer wall of the cutter body 1, and each row of spline cutting teeth 3 is arranged along the circumference of the outer wall of the cutter body 1. Multiple splines are equally spaced on each row of spline cutting teeth 3 to form spline cutting teeth. The multiple rows of spline cutting teeth 3 are parallel to each other, and the spline cutting teeth on each row of spline cutting teeth 3 are arranged opposite to a special tooth on the cutter bar 2, so that the number of spline cutting teeth processed in a single operation matches the special tooth, thereby improving the overall broaching life.

[0030] This embodiment of a special toothed broach eliminates the integral tooth structure of the original broach and adopts an assembly method. The teeth for broaching the special teeth (2.5mm small trapezoidal groove) are made into a rack cutter similar to a single-key broach, while the remaining broaches are manufactured using normal broaches. Then, the special toothed rack cutter is assembled onto the original broach (e.g., Figure 2 (As shown). This structure can effectively improve the above-mentioned abnormal problems: when the special tooth (2.5mm small trapezoidal groove) rack cutter has abnormal tooth breakage, the corresponding cutter bar 2 can be replaced, and broaching can continue, improving the utilization rate of the cutter body material and the normal teeth (spline cutting teeth 3) of the broach, thereby improving the overall life of the broach.

[0031] In this embodiment, the cutter body 1 includes a front shank, a front guide, a cutter body, a rear guide, and a rear shank connected in sequence; it realizes the broaching of the internal spline cutting teeth 3, while the part corresponding to the special teeth is designed and manufactured into a keyway shape to cooperate with the special tooth cutter bar part.

[0032] Multiple tool grooves are arranged circumferentially along the outer wall of the tool body; multiple rows of spline cutting teeth 3 are arranged axially at equal intervals on the outer wall of the tool body.

[0033] In this embodiment, the cutter bar 2 is designed according to the design method of the keyway cutter, and the non-cutting part of the cutter bar 2 is designed to fit the shape of the keyway of the broach body.

[0034] In this embodiment, the tooth rise of each row of spline cutting teeth 3 is 0.04 mm, and the tooth rise of the special teeth on the cutter bar 2 is 0.03 mm. The tooth rise of each row of spline cutting teeth 3 is higher than that of the special teeth, which can reduce the force on the special teeth.

[0035] The distance between the two connected bolt holes is 180mm, which increases the stability of the connection of the blade 2.

[0036] The length of the blade body 1 is 1785mm, and the length of the blade strip 2 is 1125mm.

[0037] This embodiment provides a special toothed insert broach (model SJ17-02148A) and an existing broach (model SJ17-02148) for parts machining tests. The comparison results are shown in Table 1.

[0038] Table 1

[0039]

[0040] This broach's single-batch lifespan was increased from 800 pieces to the same as a standard broach (1200 pieces), and its total lifespan increased from 8000 pieces to 13000 pieces, a 62.5% improvement, while the broach price only increased by 7%. This resulted in a reduction in the cost per tool from 5.3 yuan / piece to 3.5 yuan / piece, a 33.8% reduction. The cost reduction effect is significant. It also improved the material utilization rate of large broach bodies, reduced the scrap rate and tool change frequency in normal batch processing, and greatly improved the overall broaching efficiency.

[0041] The above description is merely a specific embodiment of this utility model and the effects of using such specific embodiments. However, the protection scope of this utility model is not limited thereto. Any changes or substitutions within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the scope of the claims.

Claims

1. A special toothed insert bar broach, characterized by: The application relates to a cylindrical cutter body (1) and a plurality of cutter strips (2), wherein a plurality of cutter strip grooves parallel to the central axis are formed on the outer wall of the cutter body (1) in the circumferential direction, the plurality of cutter strip grooves correspond to the circumferential positions of special teeth of an inner spline to be machined, the plurality of cutter strips (2) are arranged in the plurality of cutter strip grooves respectively, a plurality of special teeth formed by special key grooves are arranged on the cutter strip (2) at equal intervals, a plurality of rows of spline cutting teeth (3) are arranged on the outer wall of the cutter body (1) at equal intervals in the axial direction, and each row of spline cutting teeth (3) is arranged along the circumference of the outer wall of the cutter body (1). The plurality of special teeth on the cutter strip (2) correspond to the axial positions of the plurality of rows of spline cutting teeth (3) respectively.

2. The special toothed insert bar broach according to claim 1, wherein: The cutter body (1) comprises a front handle, a front guide part, a cutter body part, a rear guide part and a rear handle which are connected in sequence. The plurality of cutter strip grooves are arranged on the outer wall of the cutter body part in the circumferential direction. The plurality of rows of spline cutting teeth (3) are arranged on the outer wall of the cutter body part at equal intervals in the axial direction.

3. The special toothed insert bar broach according to claim 1, wherein: The tooth rise of each row of spline cutting teeth (3) is 0.03 mm-0.05 mm.

4. The special tooth insert bar broach of claim 1 wherein: The tooth rise of the special teeth on the cutter strip (2) is 0.02 mm-0.04 mm.

5. The special toothed insert bar broach according to claim 1 or 4, characterized in that: A plurality of bolt holes are arranged in the cutter strip grooves, and the cutter strip (2) is connected in the cutter strip grooves of the cutter body (1) by a plurality of bolts (4) penetrating through the plurality of bolt holes respectively.

6. The special tooth insert bar broach of claim 5 wherein: The interval between two adjacent bolt holes is 175 mm-185 mm.

7. The special tooth insert bar broach of claim 1 wherein, The material of the cutter strip (2) is M35, and the material of the cutter body (1) is M32.

8. The special tooth insert bar broach of claim 1 wherein, The length of the cutter body (1) is 1780 mm-1790 mm, and the length of the cutter strip (2) is 1120 mm-1130 mm.

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