Coronary disc type broaching tool, combined broaching tool and method for machining barrel rifling through combined broaching tool

Abstract

The invention relates to the technical field of cutters, and discloses a crown-shaped disc type broach, a combined broach and a method for machining barrel rifling thereof.The crown-shaped disc type broach comprises a broach body, a broach back, broach teeth and an inner hole, the broach body is of a disc type structure, and the multiple broach teeth are arranged on the outer surface of the broach body in the circumferential direction to form a crown-shaped disc type structure; the inner hole is formed in the center of the cutter body, the cutter back is arranged on one side of the cutter body, and an annular positioning protrusion is arranged at the position, corresponding to the inner hole, of the other side of the cutter body and used for positioning and installing the cutter body. According to the crown-shaped disc type broach, the broach body is of a disc type structure, and the broach teeth are arranged in the circumferential direction of the outer surface of the broach body; compared with an existing broaching tool with 16 tool teeth, the broaching tool has the advantages that the number of the tool teeth is convenient to set, 48 tool teeth can be achieved, more barrel rifling broaching requirements can be met at a time, and the broaching efficiency is improved by at least 50%.

Description

Technical Field

[0001] The present invention belongs to the technical field of cutting tools, and particularly relates to a crown disc broach for rifling processing of gun barrels. Background Art

[0002] The gun barrel is a key part of guns and cannons. The rifling processing of the inner wall of the gun barrel is one of the important processing procedures. The quality of the rifling processing directly affects the firing power of the projectile. Conventional rifling tools consist of multiple inlaid blade groups on a cylindrical tool body. The blades expand radially to complete the processing in the depth direction of the rifling. When the rifling depth is relatively deep, the blades need to be replaced to meet the processing in the depth direction. Moreover, when the number of rifling in the gun barrel is large, due to the need for the tool body to have sufficient strength, it is impossible to arrange the same number of blades as the rifling. Therefore, at least two indexings are required in the circumferential direction of the gun barrel rifling to complete the processing of all riflings. The tools using this method have the disadvantages of complex structure, difficult to guarantee the accuracy after rifling processing, fast tool wear, uncontrollable tool adjustment and replacement, and slow efficiency. The present invention aims at the existing technical problems and provides a crown disc rifling broach with simple structure, which can ensure the rifling processing accuracy, is not easy to wear, is easy to operate, and has high efficiency. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a crown disc rifling broach for gun barrel rifling processing in view of the current situation of the existing technology.

[0004] The specific solution of the present invention is as follows:

[0005] A crown disc broach includes a tool body, a tool back, tool teeth and an inner hole. The tool body adopts a disc structure, and a plurality of the tool teeth are arranged in the circumferential direction on the outer surface of the tool body to form a crown disc structure; the inner hole is arranged at the central position of the tool body, and the tool back is arranged at one side position of the tool body. In order to meet a large broaching force, the broach must have sufficient strength and stiffness, so the tool back structure is set; a ring-shaped positioning protrusion is provided at the position corresponding to the inner hole on the other side of the tool body for the positioning and installation of the tool body.

[0006] Further, a positioning keyway is provided on the ring-shaped positioning protrusion for realizing key connection between the tool body and the power tool rod.

[0007] Further, the positioning keyway adopts an end face layout or an axial layout.

[0008] Further, a tool face, a main cutting edge, a land, and a tool flank are sequentially arranged on the tool teeth; secondary cutting edges are arranged on both sides of the main cutting edge, and tool sub-flanks are arranged on both sides of the tool flank.

[0009] Furthermore, the front of the blade teeth is tilted inwards and has a front angle in the vertical direction, and the rear of the blade teeth is tilted downwards and has a rear angle in the horizontal direction.

[0010] Furthermore, a knife groove is provided between adjacent teeth, and the depth of the knife groove decreases from the front of the tooth to the back of the tooth.

[0011] Furthermore, rounded corners are provided on both sides of the top of the cutter teeth for transition, and chamfers are provided at the connection between the cutter teeth and the cutter grooves for transition.

[0012] A crown-disc combination broach comprises n crown-disc broaches, wherein the sizes of the n crown-disc broaches are d, d+af, d+2af, d+3af, d+4af, ..., d+(n-1)af in sequence; wherein the diameter of the latter broach is af larger than that of the former broach.

[0013] Furthermore, the last broach of the n crowned disc broaches is a finishing tool, and the edge of the secondary cutting edge is ground to a side clearance angle of 0.5-1° in the normal direction to improve the surface quality of the two broached side surfaces of the workpiece.

[0014] A method for machining barrel rifling with a crowned disc combined broach comprises the following steps:

[0015] 1) Determine the total number of barrel grooves m and the total depth of barrel grooves (n-1)af;

[0016] 2) Determine the depth af of all rifling cuts made by the crowned disc broach at one time;

[0017] 3) Determine the number of broach teeth m and the number of broaches n by the total depth of the rifling (n-1) af, the total number m and the depth af of one broaching;

[0018] 4) Calculate the diameter size d of each broach, and the diameter of the subsequent broach is greater than the diameter of the previous broach by a value af;

[0019] 5) Perform broaching while reciprocating in one go, and complete all the rifling depths in one go. Replace the crown cutter discs in sequence, perform broaching while reciprocating in multiple passes, until the rifling reaches its final depth.

[0020] Furthermore, the one-time reciprocating turning and broaching process is as follows:

[0021] S1: Insert the head of the knife bar into the barrel fitting from one end of the barrel fitting and pass it out of the barrel fitting from the other end;

[0022] S2: Install a crowned disc broach with a diameter of d onto the head of the tool shank;

[0023] S3: The tool bar drives the crowned disc broach to penetrate from the other end of the barrel fitting and exit from one end of the barrel fitting;

[0024] S4: remove the crowned disc broach with a diameter of d;

[0025] S5: The head of the knife bar is inserted into the barrel fitting from one end of the barrel fitting and is inserted out of the barrel fitting from the other end of the barrel fitting;

[0026] S6: Install the crowned disc broach with a diameter of d+af onto the head of the tool bar; proceed with S2-S6 in sequence until the crowned disc broach with a diameter of d+(n-1)af is removed to complete the broaching of all rifling of the barrel.

[0027] The beneficial effects of the present invention are as follows:

[0028] 1) The present invention adopts a crowned disc broach, that is, the blade body adopts a disc structure, and the teeth are arranged in the circumferential direction of the outer surface of the blade body; compared with the existing broach with 16 teeth, the number of teeth of the present invention is convenient for processing and setting, and can be 48 teeth, which can meet more barrel rifling broaching requirements at one time, and at least improve the processing efficiency by 50%.

[0029] 2) Thanks to the crowned disc structure, the present invention enables the cutter teeth to be directly processed in the circumferential direction of the cutter body, and all the cutter teeth can be processed at one time on the CNC, making the manufacturing more convenient, and the processing of the cutter teeth parameters more precise, effectively improving the broaching quality of the barrel rifling.

[0030] 3) The crowned disc structure of the present invention can realize combined processing, that is, using multiple groups of different sizes, and the diameter of the latter broach is larger than that of the previous broach by a value af, to complete the processing of the total depth of the rifling.

[0031] 4) The crown-shaped disc structure tool of the present invention has a finishing knife, which is reasonably designed at various angles to meet high-precision processing requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the overall structure of the present invention (positioning keyway end surface layout);

[0033] Figure 2 It is a schematic diagram of the overall structure of the present invention (axial layout of the positioning keyway);

[0034] Figure 3 It is a schematic diagram of the blade structure of the present invention;

[0035] Figure 4 It is a side structural schematic diagram of the present invention;

[0036] Figure 5 It is a schematic diagram of the longitudinal cross-section structure of the present invention;

[0037] Figure 6 Schematic diagram of the broach combination structure of the present invention;

[0038] Figure 7 Schematic diagram of the barrel processing flow of the present invention;

[0039] In the figure: 1, tool body; 2, tool back; 3, tool teeth; 301, rake face of tool teeth; 302, main cutting edge; 303, land; 304, flank of tool teeth; 305, secondary cutting edge; 306, secondary flank of tool teeth; 307, rake angle; 308, land width; 309, clearance angle; 310, tool tooth width; 311, fillet; 312, chamfer; 4, inner hole; 5, positioning protrusion; 6, positioning keyway. Specific embodiments

[0040] The following further describes the present invention in conjunction with the accompanying drawings of the specification.

[0041] As Figure 1 , 2 shown, a crown disc broach includes a tool body 1, a tool back 2, tool teeth 3, an inner hole 4, a positioning protrusion 5 and a positioning keyway 6;

[0042] The tool body 1 adopts a disc structure, and a number of tool teeth 3 are equidistantly arranged in the circumferential direction on the outer surface of the tool body 1. In this embodiment, the number of tool teeth 3 is 48; while the maximum number of tool teeth for existing barrel rifling processing is 16, that is, the present invention can process 48 rifling lines in one broaching, and the existing one can process at most 16 rifling lines in one broaching. The efficiency of the present invention in one broaching can be increased by at least 50%.

[0043] The tool back 2 is arranged on one side of the tool body 1, and a ring-shaped positioning protrusion 5 is provided at the position corresponding to the inner hole 4 on the other side of the tool body 1. A positioning keyway 6 is provided on the positioning protrusion 5. As Figure 1 shown, the positioning keyway can be a face layout. As Figure 2 shown, the positioning keyway can also be an axial layout. In other embodiments, structures such as positioning pin holes can also be used to realize the positioning and installation of the broach and the tool rod.

[0044] A tool groove 7 is provided between adjacent tool teeth 3, and the depth of the tool groove 7 decreases sequentially from the rake face 301 of the tool teeth to the flank 304 of the tool teeth, which is convenient for effective material discharge along the broaching direction during the broaching process and improves the smoothness during the broaching process.

[0045] As Figure 3 , 4, as shown in the tool teeth 3 structure in Figure 5, the tool teeth 3 are successively provided with a rake face 301, a main cutting edge 302, a land 303, and a flank 304; on both sides of the main cutting edge 302 are secondary cutting edges 305, and on both sides of the flank 304 are secondary flanks 306; the rake face 301 is inclined inward to form a rake angle 307 in the vertical direction, and the flank 304 is inclined downward to form a clearance angle 309 in the horizontal direction.

[0046] Setting the rake angle 307 can reduce the cutting force, lower the cutting temperature, improve the machining efficiency and tool life. During the use of the tool, it will be worn and damaged, and it can be used continuously after grinding the rake angle. When the diameter of the disk broach is smaller than the pre-set diameter, through dressing grinding, it can be used as a new tool for the previous disk broach. For example, d + 2af can be replaced by d + af, and the tool life is increased several times compared with conventional tools.

[0047] The main function of the clearance angle 309 is to reduce the friction between the flank of the broach and the workpiece, thereby improving the machining efficiency and surface quality. Specifically, the clearance angle can reduce the friction between the flank of the tool and the machined surface during cutting, thereby reducing the cutting force and cutting temperature and prolonging the service life of the tool. In addition, the clearance angle can also affect the sharpness and strength of the cutting edge. An appropriate clearance angle design can make the cutting edge sharper, reduce vibration and quality defects on the machined surface.

[0048] The land 303 of the broach plays multiple roles in the broach, mainly including guiding, calibrating the diameter, and finishing the machined surface.

[0049] Guiding function: The land can help the broach maintain the correct path during machining, prevent the tool from skewing, and ensure the machining accuracy and surface quality.

[0050] Calibrating the diameter: The land is convenient for controlling the diameter of the tool during manufacturing, ensuring the dimensional stability of the tool during machining.

[0051] Finishing function: The land can finish the machined surface and improve the smoothness and flatness of the machined surface.

[0052] As Figure 6 shown, this embodiment provides a crown disk combined broach, that is, the combined broach is formed by combining multiple (multiple groups) crown disk broaches. The sizes of n crown disk broaches are successively d, d + af, d + 2af, d + 3af, d + 4af,..., d + (n - 1)af; the last broach of the n crown disk broaches is a finishing broach, and the normal side clearance angle of the cutting edge is ground by 1°; where the diameter of the latter broach is larger than that of the previous broach by af; the n crown disk broaches achieve the total depth machining of the gun barrel rifling through n broaching operations.

[0053] As Figure 7As shown, a method for machining barrel rifling with a crowned disc combination broach comprises the following steps:

[0054] 1) Determine the total number of barrel grooves m and the total depth of barrel grooves (n-1)af;

[0055] 2) Determine the depth af of all rifling cuts made by the crowned disc broach at one time;

[0056] 3) Determine the number of broach teeth m and the number of broaches n by the total depth of the rifling (n-1) af, the total number m and the depth af of one broaching;

[0057] 4) Calculate the diameter size d of each broach, and the diameter of the subsequent broach is greater than the diameter of the previous broach by a value af;

[0058] 5) Perform broaching while reciprocating in one go, and complete the first depth of all rifling in one go. Replace the crown cutter disc in sequence, perform multiple reciprocating broaching while rotating, until the final depth of the rifling is completed.

[0059] The process of one reciprocating turning and broaching is as follows:

[0060] S1: Insert the head of the knife bar into the barrel fitting from one end of the barrel fitting and pass it out of the barrel fitting from the other end;

[0061] S2: Install a crowned disc broach with a diameter of d onto the head of the tool shank;

[0062] S3: The tool bar drives the crowned disc broach to penetrate from the other end of the barrel fitting and exit from one end of the barrel fitting;

[0063] S4: remove the crowned disc broach with a diameter of d;

[0064] S5: The head of the knife bar is inserted into the barrel fitting from one end of the barrel fitting and is inserted out of the barrel fitting from the other end of the barrel fitting;

[0065] S6: Install the crowned disc broach with a diameter of d+af onto the head of the tool bar; proceed with S2-S6 in sequence until the crowned disc broach with a diameter of d+(n-1)af is removed to complete the broaching of all rifling of the barrel.

[0066] The number of teeth of the crowned disc broach of the present invention is consistent with the number of rifling of the workpiece, and one broaching can complete one af depth of all rifling. The existing dispersed blades are limited by the rigidity of the body, and can only install 16 blades, and three broachings are required to complete one af depth broaching of all rifling.

[0067] Each structural element of the cutting teeth of the coronal broach of the present invention, such as the rake face of the cutting tooth, the main cutting edge, the land, the flank of the cutting tooth, the secondary cutting edge, the secondary flank of the cutting tooth, etc., is arranged on the disk and completed under the same process equipment and process, forming various angles such as the rake angle, clearance angle, secondary clearance angle, main cutting edge angle of the tool, and strong dimensional consistency such as the cutting tooth width, R angle, C angle, etc. Compared with the dispersed layout of conventional inserts, it is easier to manufacture and the manufacturing accuracy is easier to guarantee.

[0068] When the coronal cutter head of the present invention broaches the rifling of the gun barrel, the rifling depth is broached by multiple groups of coronal cutters. The grouped coronal cutter heads rotate and broach while reciprocating once, and all the rifling is broached to a certain depth in one pass. Then the coronal cutter heads are replaced successively, and the rifling is broached while rotating and reciprocating multiple times until the final depth of the rifling is broached; only the generating motion of the reciprocating motion and the rotational motion is required, without a circumferential feed structure, and the structure is compact.

Claims

1. A crowned disc broach, characterized in that: The invention comprises a knife body (1), a knife back (2), knife teeth (3) and an inner hole (4); the knife body (1) adopts a disc structure, and a plurality of the knife teeth (3) are arranged in the circumferential direction of the outer surface of the knife body (1) to form a crown-shaped disc structure; the inner hole (4) is arranged at the center of the knife body (1), the knife back (2) is arranged at one side of the knife body (1), and the other side of the knife body (1) is provided with an annular positioning protrusion (5) at a position corresponding to the inner hole (4) for positioning and installing the knife body (1).

2. A crowned disc broach according to claim 1, characterized in that: The annular positioning protrusion (5) is provided with a positioning keyway (6) for realizing a key connection between the tool body and the power tool rod; the positioning keyway (6) adopts an end surface layout or an axial layout.

3. A crowned disc broach according to claim 1, characterized in that: The tooth (3) is provided with a tooth front face (301), a main cutting edge (302), a cutting edge band (303), and a tooth rear face (304) in sequence; both sides of the main cutting edge (302) are auxiliary cutting edges (305), and both sides of the tooth rear face (304) are tooth auxiliary rear faces (306).

4. A crowned disc broach according to claim 3, characterized in that: The front face (301) of the blade teeth is tilted inwards and has a front angle (307) in the vertical direction, and the rear face (304) of the blade teeth is tilted downwards and has a rear angle (309) in the horizontal direction.

5. A crowned disc broach according to claim 3, characterized in that: A knife groove (7) is provided between adjacent knife teeth (3), and the depth of the knife groove (7) decreases gradually from the front face (301) of the knife tooth to the rear face (304) of the knife tooth.

6. A crowned disc broach according to claim 5, characterized in that: Rounded corners (311) are arranged on both sides of the top of the blade tooth (3) for transition, and chamfers (312) are arranged at the connection between the blade tooth (3) and the blade groove (7) for transition.

7. A crown-disc combined broach, characterized in that: It comprises n crown-disc broaches as described in any one of claims 1-6, and the sizes of the n crown-disc broaches are d, d+af, d+2af, d+3af, d+4af, ..., d+(n-1)af in sequence; wherein the diameter of the latter broach is af larger than that of the former broach.

8. A crowned disc broach according to claim 7, characterized in that: The last broach of the n crown-shaped disc broaches is a finishing tool, and the edge of the secondary cutting edge (305) is ground to a side clearance angle of 0.5-1° in the normal direction to improve the surface quality of the two broached sides of the workpiece.

9. A method for machining barrel rifling using a crowned disc combined broach as claimed in claim 8, characterized in that: The steps include: 1) Determine the total number of barrel grooves m and the total depth of barrel grooves (n-1)af; 2) Determine the depth af of all rifling cuts made by the crowned disc broach at one time; 3) Determine the number of broach teeth m and the number of broaches n by the total depth of the rifling (n-1) af, the total number m and the depth af of one broaching; 4) Calculate the diameter size d of each broach, and the diameter of the subsequent broach is greater than the diameter of the previous broach by a value af; 5) Perform broaching while reciprocating in one go, and complete the first depth of all rifling in one go. Replace the crown cutter disc in sequence, perform multiple reciprocating broaching while rotating, until the final depth of the rifling is completed.

10. A method for machining barrel rifling using a crowned disc combined broach as claimed in claim 9, characterized in that: The one-time reciprocating turning and broaching process is as follows: S1: Insert the head of the shank into one end of the barrel fitting and pass it out from the other end of the barrel fitting; S2: Install a crowned disc broach with a diameter of d onto the head of the tool shank; S3: The tool bar drives the crowned disc broach to penetrate from the other end of the barrel fitting and exit from one end of the barrel fitting; S4: remove the crowned disc broach with a diameter of d; S5: The head of the knife bar is inserted into the barrel fitting from one end of the barrel fitting and is inserted out of the barrel fitting from the other end of the barrel fitting; S6: Install the crowned disc broach with a diameter of d+af onto the head of the tool bar; proceed with S2-S6 in sequence until the crowned disc broach with a diameter of d+(n-1)af is removed to complete the broaching of all rifling of the barrel.

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