Spline centering broach

Abstract

The utility model relates to a broach, in particular to a spline centering broach. The broach comprises a front handle, a broach body and a rear handle which are sequentially connected from front to back. The peripheral surface of the cutter body comprises a press polish section, a rough broaching round hole section, a rough broaching spline section, a finish broaching spline section and a finish broaching round hole section which are sequentially connected from front to back; the finish broaching round hole section comprises a plurality of groups of spline guide teeth and finish broaching round hole teeth which are arranged in the circumferential direction; the outer diameter of the spline guide teeth is larger than that of the finish broaching round hole teeth, and the multiple sets of spline guide teeth and the multiple sets of finish broaching round hole teeth are sequentially arranged at intervals in the direction from the front handle to the rear handle. A first gap is formed between the tooth side face of the spline guide tooth and the side face of the machined spline groove, and a second gap is formed between the large-diameter outer surface of the spline guide tooth and the groove bottom face of the machined spline groove. According to the spline broach, a brand new broach body structure is adopted, and the defect that the concentricity is low when an existing spline broach is used for machining large-tooth-height internal splines is well overcome through accurate matching between the spline guide teeth and the machined spline grooves.

Description

Technical Field

[0001] The utility model relates to a broach, in particular to a spline centering broach. Background Art

[0002] At present, the structure of the broach body of the commonly used broaches at home and abroad is generally: round hole guide section → rough round hole section → fine round hole section → rough spline section → fine spline section. Due to the poor rigidity and easy deformation of thin-walled parts, the problem of large taper of round hole and spline teeth thickness is easy to appear after broaching with this structure; and there are many special-shaped teeth in thin-walled parts, and the workpiece often has large spline tooth cumulative error and large outer diameter runout after processing, resulting in low concentricity between the spline pitch circle and the round hole, which seriously affects the quality of the parts.

[0003] Chinese patent CN201338133Y discloses a combined involute spline broach, comprising a tool rod, a front guide sleeve, a small-diameter centering involute spline broach, a plane broach, a strip guide strip and a rear guide sleeve. The small-diameter centering involute spline broach sleeve is arranged on the tool rod, the front guide sleeve is sleeved on the outer end of the small-diameter centering involute spline broach on the tool rod and fixedly connected to the tool rod, the strip guide strip and the plane broach are respectively fixedly connected to the tool rod, and the rear guide sleeve is sleeved on the outer ends of the strip guide strip and the plane broach on the tool rod and fixedly connected to the tool rod.

[0004] The combined involute spline broach adopts a small-diameter centering involute spline broach. Although it can improve the concentricity between the spline pitch circle and the circular hole after processing to a certain extent, its concentricity is still relatively low and it is difficult to meet actual usage requirements. Utility Model Content

[0005] The utility model aims to solve the technical problem that the existing spline broaches have low concentricity between the spline pitch circle and the circular hole after processing and are difficult to meet the actual use requirements, and provide a spline centering broach.

[0006] In order to solve the above technical problems, the technical solutions provided by the utility model are as follows:

[0007] A spline centering broach, which is special in that:

[0008] It includes a front handle, a knife body and a rear handle which are sequentially connected from front to rear;

[0009] The outer peripheral surface of the cutter body includes a calendering section, a rough-drawn round hole section, a rough-drawn spline section, a fine-drawn spline section and a fine-drawn round hole section which are sequentially connected from front to back;

[0010] The precision-drawn circular hole section comprises a plurality of groups of spline guide teeth arranged in the circumferential direction and a plurality of groups of precision-drawn circular hole teeth arranged in the circumferential direction; the outer diameter of the spline guide teeth is larger than the outer diameter of the precision-drawn circular hole teeth, and the plurality of groups of spline guide teeth and the plurality of groups of precision-drawn circular hole teeth are sequentially spaced from the front handle to the rear handle;

[0011] A first gap is provided between the tooth side surface of the spline guide tooth and the side surface of the processed spline groove, and a second gap is provided between the large diameter outer surface of the spline guide tooth and the groove bottom surface of the processed spline groove.

[0012] Furthermore, the spline guide teeth are negative rake angle spline guide teeth.

[0013] Furthermore, the front cutting edge angle A of the spline guide tooth is -75°, and the top cutting edge angle B is -85°.

[0014] Furthermore, the first gap is 0.005 mm, and the width of the second gap is 0.1 mm.

[0015] Furthermore, the tooth thickness S of the spline guide tooth T For: S T =S C -0.01;

[0016] In the formula, S C is the tooth thickness of the machined spline teeth.

[0017] Outer diameter D of spline guide teeth T For: D T =D ei -0.2;

[0018] Where D ei It is the major diameter of the processed spline teeth.

[0019] Compared with the prior art, the utility model has the following beneficial effects:

[0020] 1. The utility model adopts a brand-new tool body structure - calendering section + rough-drawn round hole section + rough-drawn spline section + fine-drawn spline section + fine-drawn round hole section, and adopts a fine-drawn round hole section of a spline guide tooth + fine-drawn round hole tooth structure. After the fine-drawn spline section is used to achieve fine processing of the spline groove, the precise cooperation between the spline guide tooth and the processed spline groove can better overcome the disadvantage of low concentricity of the existing spline broach when processing large tooth height internal splines, and achieve the purpose of extremely high concentricity between the spline pitch circle and the fine-drawn round hole after processing, and the concentricity is less than 0.015mm, which meets the actual use requirements of high precision.

[0021] 2. The structures of the various groups of spline guide teeth in the utility model are the same, which is simpler to manufacture and has a lower cost than the traditional high and low teeth.

[0022] 3. The spline guide teeth in the utility model are only used for guiding but not for processing, so the broaching force of the round hole part of the traditional high and low tooth broach is smaller, the processing defects are less, and the service life is longer. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the structure of an embodiment of the utility model;

[0024] Figure 2 It is a partial structural schematic diagram of the precision-drawn circular hole segment in the embodiment of the utility model;

[0025] Figure 3 for Figure 2 Left view of .

[0026] Explanation of the accompanying drawings: 1-front handle, 2-blade body, 21-calendering section, 22-rough-drawn round hole section, 23-rough-drawn spline section, 24-fine-drawn spline section, 25-fine-drawn round hole section, 251-spline guide tooth, 252-fine-drawn round hole tooth, 3-rear handle. DETAILED DESCRIPTION

[0027] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0028] See also Figure 1 The present embodiment is a spline centering broach, comprising a front handle 1, a tool body 2 and a rear handle 3 connected in sequence from front to back; wherein the outer circumferential surface of the tool body 2 comprises a calendering section 21, a rough-drawn circular hole section 22, a rough-drawn spline section 23, a fine-drawn spline section 24 and a fine-drawn circular hole section 25 connected in sequence from front to back.

[0029] Specifically, due to the special structure of precision-drawn round holes, the precision-drawn round hole section in the commonly used broach structure usually adopts the staggered broaching of spline precision-drawn teeth and round hole teeth. Due to the existence of the side clearance of the broach teeth, it is actually the part of the spline precision-drawn teeth close to the large diameter that is broached alternately with the round hole teeth, and the coaxiality of the spline pitch circle and the small diameter round hole cannot be strictly guaranteed. Especially when the spline tooth height is large, the difference between the broached part of the spline teeth and the pitch circle is larger, and the broaching accuracy is also worse.

[0030] This embodiment adopts a special fine-drawn round hole segment 25, see Figure 1 and Figure 2The precision-drawn circular hole segment 25 includes a plurality of groups of spline guide teeth 251 arranged along the circumferential direction and a plurality of groups of precision-drawn circular hole teeth 252 arranged along the circumferential direction. The outer diameter of the spline guide teeth 251 is greater than the outer diameter of the precision-drawn circular hole teeth 252. In the present embodiment, the number of the spline guide teeth 251 and the precision-drawn circular hole teeth 252 are both 2 groups for illustration. In other embodiments of the present invention, those skilled in the art may also make specific settings according to the tool size, such as 3, 4, etc.

[0031] Two groups of spline guide teeth 251 and two groups of precision-drawn round hole teeth 252 are arranged in sequence from the front handle 1 to the rear handle 3. That is, a spline guide tooth 251 is arranged first, and then a precision-drawn round hole tooth 252 is arranged, and so on. In this embodiment, a total of two groups of spline guide teeth 251 and two groups of precision-drawn round hole teeth 252 are arranged; the front tooth is the spline guide tooth 251, and the rear tooth is the precision-drawn round hole tooth 252. The spline guide tooth 251 in this embodiment is specifically a spline guide tooth with a negative rake angle and without drawing the full tooth profile. Specifically, the front cutting edge angle A of the spline guide tooth 251 is -75°, and the top cutting edge angle B is -85°; the tooth thickness ST of the spline guide tooth 251 is SC-0.01, and the outer diameter DT is Dei-0.2; wherein SC is the tooth thickness of the processed spline tooth, and Dei is the major diameter of the processed spline tooth.

[0032] The above-mentioned precision-drawn circular hole segment 25 can fully place the precision-drawn circular hole tooth 252 in a theoretical position that is strictly concentric with the spline, and use the spline to position the precision-drawn circular hole to ensure that when the workpiece is aligned with the minor diameter, the spline cumulative error has good accuracy. After drawing, the concentricity of the spline minor diameter and the pitch circle is less than 0.015mm, and the runout of the part outer diameter is increased to no more than 0.015mm.

[0033] At the same time, in order to avoid the spline guide teeth 251 and the processed spline groove from interfering with each other, thereby causing the processed spline groove to be squeezed and damaged, see Figure 3 A first gap is provided between the tooth side surface of the spline guide tooth 251 and the side surface of the processed spline groove, and the first gap is 0.005 mm; a second gap is provided between the large diameter outer surface of the spline guide tooth 251 and the groove bottom surface of the processed spline groove, and the width of the second gap is 0.1 mm.

[0034] Combined with traditional design methods, the remaining parameter designs of the involute spline broach are completed (such as the involute broach design part in the <Tool Design Manual> edited by Yuan Zhejun and Liu Huaming published by Machinery Industry Press).

[0035] In addition to the above-mentioned structure, the remaining calendering section 21, the rough-drawn circular hole section 22, the rough-drawn spline section 23, and the fine-drawn spline section 24 are all existing structures.

[0036] The above is only a specific implementation of the utility model, but the protection scope of the utility model is not limited thereto. Any changes or replacements within the technical scope disclosed in the utility model should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model should be based on the protection scope recorded in the claims.

Claims

1. A spline centering broach, characterized in that: It comprises a front handle (1), a knife body (2) and a rear handle (3) which are connected in sequence; The outer peripheral surface of the knife body (2) comprises a calendering section (21), a rough-drawn circular hole section (22), a rough-drawn spline section (23), a fine-drawn spline section (24) and a fine-drawn circular hole section (25) which are sequentially connected from the front handle (1) to the rear handle (3); The fine-drawn circular hole segment (25) comprises a plurality of groups of spline guide teeth (251) arranged along the circumferential direction and a plurality of groups of fine-drawn circular hole teeth (252) arranged along the circumferential direction; The outer diameter of the spline guide teeth (251) is greater than the outer diameter of the finely drawn round hole teeth (252), and a plurality of groups of the spline guide teeth (251) and a plurality of groups of finely drawn round hole teeth (252) are sequentially arranged at intervals in the direction from the front handle (1) to the rear handle (3); A first gap is provided between the tooth side surface of the spline guide tooth (251) and the side surface of the processed spline groove, and a second gap is provided between the large-diameter outer surface of the spline guide tooth (251) and the groove bottom surface of the processed spline groove.

2. A spline centering broach according to claim 1, characterized in that: The spline guide teeth (251) are negative rake angle spline guide teeth.

3. A spline centering broach according to claim 2, characterized in that: The front cutting edge angle A of the spline guide tooth (251) is -75°, and the top cutting edge angle B is -85°.

4. A spline centering broach according to any one of claims 1 to 3, characterized in that: The width of the first gap is 0.005 mm, and the width of the second gap is 0.1 mm.

5. A spline centering broach according to claim 4, characterized in that: The tooth thickness S of the spline guide tooth (251) is T for: S T =S C -0.01; Where: S C is the thickness of the machined spline teeth.

6. A spline centering broach according to claim 5, characterized in that: The outer diameter D of the spline guide tooth (251) T for: D T =D ei -0.2; Where: D ei It is the major diameter of the processed spline teeth.

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