Gear internal spline push broach

Abstract

The utility model discloses a gear internal spline push broach which comprises a guide column, the front end of the guide column close to the end is provided with front guide teeth, the middle of the guide column is sequentially provided with a cutting guide portion and a cutting correction portion from front to back, the rear end of the guide column close to the end is provided with rear guide teeth, and the end face of the rear end is fixedly connected with a handle portion. The front end of the front guide tooth is of a conical structure, and a plurality of first cutting edges with the heights sequentially increased are arranged on the inclined face of the conical structure. By means of the first cutting edge, a gear hole can be cut firstly in the moving process of the front guide teeth, the front guide teeth are made to be completely matched with the gear hole, the front guide teeth are prevented from excessively extruding the gear hole, large extrusion stress on the gear hole is avoided, and the probability that cracks are generated in a gear is reduced; the inner diameter of the spline groove can be corrected and cut through the third cutting edge, and the precision of the inner diameter of the spline groove is guaranteed.

Description

Technical Field

[0001] The utility model relates to the technical field of gear processing, in particular to an internal spline broach for gears. Background Art

[0002] In the process of gear processing, when the gear is heat-treated, the problem of deformation of the reference hole will occur. Therefore, in order to ensure the quality of tooth profile finishing, the reference hole must be corrected. For gears with internal splines, a spline broach is generally used to correct the reference hole. For example, in patent CN213379320U, an internal spline broaching tool for gears is disclosed, which includes: a front guide member of the tool; a cutting member is integrally arranged at the rear end of the front guide member of the tool; the cutting member further includes a broach; the broach is fixedly arranged outside the cutting member; the number of the broaches is set to twelve groups; a calibration member is integrally arranged at the rear end of the cutting member; the calibration member further includes calibration teeth; the calibration teeth are fixedly arranged outside the calibration member. When the tool is in use, the broach can only correct and cut the outer diameter and side wall of the spline, and cannot correct and cut the inner diameter of the spline located at the bottom of the broach. On the other hand, since the radius of the arc teeth on the front guide member of the tool is greater than the inner diameter of the gear spline, when the front guide member of the tool is inserted into the spline, an extrusion force will be generated on the inner diameter of the gear. If it is forcibly inserted, it may cause an increase in the internal stress of the gear, generate a large extrusion stress, and in severe cases, it may cause cracks inside the gear, posing a safety hazard. Summary of the Utility Model

[0003] The purpose of the utility model is to provide an internal spline broach for gears, which has the advantages that the inner diameter of the spline can be corrected and cut through the third cutting edge, the preliminary trimming of the spline groove can be completed when the guide post moves through the first cutting edge, the gear hole diameter can be gradually enlarged to make the front guide teeth fully fit the gear hole diameter, and no large extrusion stress will be generated on the gear.

[0004] In order to achieve the above purpose, the technical scheme adopted by the utility model is: an internal spline broach for gears, including a guide post, a front guide tooth is arranged near the end of the front end of the guide post, a cutting guide part and a cutting correction part are arranged in sequence from front to back in the middle of the guide post, a rear guide tooth is arranged near the end of the rear end of the guide post, and a handle part is fixedly connected to the end face of the rear end. The front end of the front guide tooth is a conical structure, and a plurality of first cutting edges with gradually increasing heights are arranged on the inclined surface of the conical structure.

[0005] Furthermore, a plurality of groups of cutting groups are installed along the axial direction of the guide post on both the cutting guide part and the cutting correction part. Each group of cutting groups includes a plurality of cutting teeth, and the plurality of cutting teeth are arranged in a circumferential arrangement along the outer wall of the guide post. The upper end of the cutting tooth is a second cutting edge. Among them, the second cutting edge on the cutting guide part is flush with the highest first cutting edge in height, and the height of the second cutting edge on the cutting correction part increases in sequence.

[0006] Further, a third cutting edge for cutting the inner diameter of the spline is provided at the gap between several circumferentially arranged cutting teeth, and the heights of the third cutting edges on the cutting and correcting portion increase successively.

[0007] Further, the height increase amount between adjacent first cutting edges is 0.1 - 0.6 mm, and the connection line of the vertices of the first cutting edges is an involute.

[0008] Further, the height increase amount between adjacent second cutting edges and the height increase amount between adjacent third cutting edges on the cutting and correcting portion are both 0.1 - 0.3 mm, and the connection lines of the vertices of the second cutting edges and the connection lines of the vertices of the third cutting edges at this position are involutes with the same linear shape.

[0009] Further, a chip fluting is provided between adjacent groups of cutting groups.

[0010] Further, the number of the front guiding teeth, the cutting teeth of each cutting group, and the rear guiding teeth is the same, and they are arranged on the same straight line.

[0011] Compared with the prior art, the advantages of the present utility model are as follows:

[0012] Through the first cutting edge, the gear hole can be cut in advance during the movement of the front guiding teeth, so that the front guiding teeth are fully adapted to the gear hole, avoiding excessive extrusion of the gear hole by the front guiding teeth, avoiding generating large extrusion stress on the gear hole, and reducing the probability of cracks generated inside the gear; through the third cutting edge, the inner diameter of the spline groove can be corrected and cut to ensure the accuracy of the inner diameter of the spline groove. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a schematic structural view of the present utility model;

[0014] Figure 2 is Figure 1 the b-b view of

[0015] Figure 3 is Figure 1 the enlarged view of part A of

[0016] In the figure: 1, guiding column; 2, front guiding teeth; 3, cutting guiding portion; 4, cutting and correcting portion; 5, rear guiding teeth; 6, handle portion; 7, first cutting edge; 8, cutting teeth; 9, second cutting edge; 10, third cutting edge; 11, chip fluting. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] The present utility model will be further described below.

[0018] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts belong to the scope of protection of this application.

[0019] Therefore, the following detailed description of the embodiments of this application provided in the drawings is not intended to limit the scope of this application that is claimed, but merely represents selected embodiments of this application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts belong to the scope of protection of this application.

[0020] Please refer to Figures 1 - 3

[0021] A gear internal spline broach includes a guide post 1. At the front end of the guide post 1 near the end, a front guide tooth 2 is provided. In the middle of the guide post 1, a cutting guide part 3 and a cutting correction part 4 are successively arranged from front to back. At the rear end of the guide post 1 near the end, a rear guide tooth 5 is provided, and a handle part 6 is fixedly connected to the end face at the rear end. The front end of the front guide tooth 2 is of a conical structure, and several first cutting edges 7 with gradually increasing heights are provided on the inclined surface of the conical structure.

[0022] The front guide tooth 2 is arranged at a position 2 - 4 cm backward from the front end face of the guide post 1. The outer diameter of the guide post 1 is slightly smaller than the inner diameter of the gear spline, facilitating the front end of the guide post 1 to move in the reference hole of the gear and achieving the rapid positioning of the guide post 1. The inclination angle of the conical structure is 2° - 3°, and the guiding effect is achieved through this inclination angle.

[0023] The height increase amount between each group of adjacent first cutting edges 7 is 0.1 - 0.6 mm, and the connection line of the vertices of several first cutting edges 7 is an involute. The height of the first cutting edge 7 with the lowest height is 0.5 mm. When the front guide tooth 2 moves in the gear spline, the reference hole of the gear is gradually and slowly corrected through the first cutting edges 7 arranged in an involute. Specifically: when the front guide tooth 2 moves forward, first, the inner diameter of the gear spline groove is cut by the lowest first cutting edge 7 to slightly expand the gear hole diameter. When the adjacent next first cutting edge 7 moves into the gear spline groove, the gear hole diameter is slightly expanded again. Repeating this way, the gear hole can be cut in layers and the gear hole can be slightly expanded in layers, avoiding large extrusion stress on the inner diameter of the gear spline when the front guide tooth 2 moves forward.

[0024] Specifically, in this embodiment, a plurality of sets of cutting groups are installed along the axial direction of the guiding column 1 on both the cutting guiding portion 3 and the cutting correction portion 4. Each set of cutting groups includes a plurality of cutting teeth 8, and the plurality of cutting teeth 8 are arranged in a circumferential direction along the outer wall of the guiding column 7. The upper end of the cutting tooth 8 is a second cutting edge 9. Among them, the height of the second cutting edge 9 on the cutting guiding portion 3 is flush with the height of the first cutting edge 7 with the maximum height, and the height of the second cutting edge 9 on the cutting correction portion 4 increases successively.

[0025] According to the thickness of the processed gear, the cutting guiding portion 3 is located at 0.5 - 1 cm behind the rear end of the front guiding tooth 2, as long as the distance is less than the thickness of the gear, ensuring that the rear end of the front guiding tooth 2 and the front end of the cutting guiding portion 3 can be simultaneously located in the gear hole to achieve the guiding function of the front guiding tooth 2; 4 - 10 sets of cutting groups are provided on the cutting guiding portion 3. In this embodiment, preferably 4 sets of cutting groups are provided. After the front guiding tooth 2 passes through the gear hole, the outer diameter and side wall of the spline groove are further slightly corrected by the second cutting edge 9 on the cutting guiding portion 3; the cutting correction portion 4 is provided with 3 sets of cutting groups, and the height increase amount between adjacent second cutting edges 9 on the cutting correction portion 4 is 0.1 - 0.3 mm. The connection line of the vertices of the plurality of second cutting edges 9 is an involute. The gear spline groove is corrected layer by layer through the second cutting edge 9. Of course, according to the actual size and processing accuracy requirements of the gear, several different sets of gear groups can also be set. For example, 6 sets of cutting groups are provided on the cutting guiding portion 3, and 12 sets of cutting groups are provided on the cutting correction portion 4, etc.

[0026] The front end face and the rear end face of the cutting tooth 8 are both arc-shaped structures and are recessed towards the vertical center line of the cutting tooth 8. That is to say, a chip groove 11 is formed between the front end face and the rear end face of adjacent cutting teeth 8. The rear end face of the chip groove is an arc-shaped structure (i.e., the front end face of the latter cutting tooth 8 among adjacent cutting teeth 8). The chips after cutting and correction by the second cutting edge 9 will slide down into the chip groove 11 through this arc-shaped structure and move out of the gear hole through the gap between adjacent cutting teeth 8, avoiding chip blockage.

[0027] A third cutting edge 10 for cutting the inner diameter of the spline is provided at the gap between the circumferentially arranged plurality of cutting teeth 8, and the height of the third cutting edge 10 on the cutting correction portion 4 increases successively. For the plurality of third cutting edges 10, the height increase amount between adjacent second cutting edges 9 and the height increase amount between adjacent third cutting edges 10 on the cutting correction portion 4 are both 0.1 - 0.3 mm, and the connection line of the vertices of the second cutting edges 9 at this position and the connection line of the vertices of the third cutting edges 10 are both involutes with the same linear shape. The inner diameter of the spline groove can be cut and corrected through the third cutting edge 10.

[0028] The number of the front guiding teeth 2, the cutting teeth 8 of each set of cutting groups, and the rear guiding teeth 5 is the same and they are arranged on the same straight line.

[0029] The first cutting edge 7, the second cutting edge 9, and the third cutting edge 10 are all made of high-hardness alloy materials, such as tungsten steel materials, which have the advantages of good hot hardness, wear resistance, good strength and ductility, high temperature resistance, corrosion resistance, etc., and are convenient for the cutting and correction of gears.

[0030] Principle of the present utility model:

[0031] During use, first insert the front end of the guide post 1 into the gear hole, and then apply a thrust force to the handle part 6 at the rear end of the guide post 1 through an existing press, so that the front guide teeth 1, the cutting guide part 3, the cutting and correction part 4, and the rear guide teeth 5 sequentially pass through the gear hole, and correct and cut the gear spline groove. Among them, through the first cutting edge 7, the gear hole can be cut one step ahead during the movement of the front guide teeth 1, so that the front guide teeth 1 are fully adapted to the gear hole, avoiding excessive extrusion of the gear hole by the front guide teeth, avoiding generating a large extrusion stress on the gear hole, and reducing the probability of cracks generated inside the gear; through the third cutting edge 10, the inner diameter of the spline groove can be corrected and cut to ensure the accuracy of the inner diameter of the spline groove. Finally, after the cutting and correction are completed, the smooth retraction of the push knife is realized through the rear guide teeth 5.

[0032] In this article, specific examples are used to elaborate on the principle and implementation mode of the present utility model. The description of the above embodiments is only used to help understand the method and its core idea of the present utility model; at the same time, for those of ordinary skill in the art, according to the idea of the present utility model, there will be changes in the specific implementation mode and application scope. It is possible to make changes and improvements to the present utility model without exceeding the concept and scope defined by the appended claims. In summary, the content of this specification should not be construed as a limitation to the present utility model.

Claims

1. A gear internal spline broach, characterized in that: It includes a guide post (1). At the front end of the guide post (1) near the end, a front guide tooth (2) is provided. In the middle of the guide post (1), a cutting guide part (3) and a cutting correction part (4) are arranged in sequence from front to back. At the rear end of the guide post (1) near the end, a rear guide tooth (5) is provided, and a handle part (6) is fixedly connected to the end face at the rear end. The front end of the front guide tooth (2) is a conical structure, and a plurality of first cutting edges (7) with gradually increasing heights are provided on the inclined surface of the conical structure.

2. The internal spline broach for gear according to claim 1, characterized in that: In the cutting guide part (3) and the cutting correction part (4), a plurality of groups of cutting groups are installed along the axial direction of the guide post (1). Each group of cutting groups includes a plurality of cutting teeth (8), and the plurality of cutting teeth (8) are arranged in a circumferential direction on the outer wall of the guide post (1). The upper end of the cutting tooth (8) is a second cutting edge (9). Among them, the second cutting edge (9) on the cutting guide part (3) is flush with the first cutting edge (7) with the maximum height, and the height of the second cutting edge (9) on the cutting correction part (4) increases in sequence.

3. A gear internal spline broach according to claim 2, characterized in that: A third cutting edge (10) for cutting the inner diameter of the spline is provided at the gap between the plurality of circumferentially arranged cutting teeth (8), and the height of the third cutting edge (10) on the cutting correction part (4) increases in sequence.

4. A gear internal spline broach according to claim 3, characterized in that: The height increase amount between adjacent first cutting edges (7) is 0.1 - 0.6 mm, and the connection line of the vertices of the first cutting edges (7) is an involute.

5. A gear internal spline broach according to claim 4, characterized in that: The height increase amount between adjacent second cutting edges (9) and the height increase amount between adjacent third cutting edges (10) on the cutting correction part (4) are both 0.1 - 0.3 mm, and the connection line of the vertices of the second cutting edges (9) and the connection line of the vertices of the third cutting edges (10) at this position are involutes with the same linear shape.

6. A gear internal spline broach according to claim 5, characterized in that: A chip groove (11) is provided between adjacent groups of cutting groups.

7. A gear internal spline broach according to claim 6, characterized in that: The number of the front guide teeth (2), the cutting teeth (8) of each group of cutting groups, and the rear guide teeth (5) is the same, and they are arranged on the same straight line.

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