Composite spline broach

Abstract

A composite spline broach comprises a circular cutting tooth part and a spline tooth part, and the circular cutting tooth part comprises circular rough cutting teeth, circular fine cutting teeth and circular calibration teeth which are sequentially arranged; the circular calibration teeth comprise two rows of calibration teeth which are arranged in a front-back adjacent mode, each row of calibration teeth is provided with a chip separating groove, the chip separating grooves are formed in the middle of the tooth thickness of the spline teeth, and the chip separating grooves of the two adjacent rows of calibration teeth are arranged in a staggered mode in the circumferential direction. The scrap iron is broken and curled in the direction of the scrap separating groove in the cutting process.

Description

Technical field

[0001] The present application relates to the field of mechanical processing technology, and in particular to a composite spline broach. [Background Technology]

[0002] A compound spline broach features circular teeth at the front and spline teeth at the rear, enabling the machining of both a circular hole and a spline groove in a single broaching operation. In existing technology, the circular cutting teeth of a compound spline broach comprise roughing teeth, finishing teeth, and calibration teeth. Chip splitters are typically ground into the roughing and finishing teeth to break and curl the resulting chips, facilitating their timely removal.

[0003] However, in existing technology, circular calibrating teeth are typically not ground with chip grooves. While this can avoid chip groove marks on workpieces with smaller diameters, the cutting process produces a continuous ring of chips that do not break or curl. This continuous ring of chips not only affects the surface finish of the workpiece but also requires manual cleaning after each broaching, which is time-consuming and labor-intensive, seriously affecting processing efficiency. [Utility Model Content]

[0004] In view of this, an embodiment of the present application provides a composite spline broach that can solve the technical problem in the prior art that the iron chips generated by the circular calibration teeth cannot be broken and curled, require manual cleaning and affect the surface quality of the workpiece.

[0005] The composite spline broach provided in the embodiment of the present application includes:

[0006] a circular cutting tooth portion and a spline tooth portion, wherein the circular cutting tooth portion comprises a circular rough cutting tooth, a circular fine cutting tooth and a circular calibration tooth which are arranged in sequence;

[0007] The circular calibration teeth include two rows of calibration teeth arranged adjacent to each other in front and back, and each row of the calibration teeth is provided with a chip groove, and the chip groove is arranged in the middle part of the tooth thickness of the spline teeth. The chip grooves of the two adjacent rows of calibration teeth are staggered in the circumferential direction so that the iron chips are broken and curled along the direction of the chip groove during the cutting process.

[0008] Optionally, a first chip groove is provided on both the circular rough cutting teeth and the circular fine cutting teeth, the width of the first chip groove is 0.5-1.0mm, and the depth is 0.8-1.2mm; the chip groove on the circular calibration tooth has a width of 0.5-1.2mm, a depth of 0.3-0.8mm, and an opening inclination angle of 30-60 degrees, which is used to control the degree of curling of the iron chips.

[0009] Optionally, the total length of the circular cutting tooth portion is 80-120 mm, wherein the axial length of the circular rough cutting teeth is 30-40 mm, the axial length of the circular fine cutting teeth is 20-30 mm, and the axial length of the circular calibration teeth is 30-50 mm.

[0010] Optionally, the diameter difference between the roughing teeth, the fine-cutting teeth and the calibration teeth is 0.01-0.08. The roughing teeth 11 have 6-12 teeth, the fine-cutting teeth 12 have 3-5 teeth, and the calibration teeth 13 have 3-5 teeth.

[0011] Optionally, the axial length of the spline tooth portion is 200-600 mm, and includes 30-120 equally spaced spline teeth, and the spline teeth are arranged parallel to the broach axis.

[0012] Optionally, the cross-sections of the first chip dividing groove and the chip dividing groove are V-shaped, the groove bottom of the V-shaped groove is in an arc transition, and the radius of the groove bottom arc is 0.2-0.5mm, so as to enhance the strength of the chip dividing groove and extend the service life.

[0013] Optionally, the angle between the bottom surface of the chip groove of the circular calibration tooth and the radial center line of the broach is 15-30 degrees, which is used to adjust the flow direction and curling diameter of the iron chips.

[0014] Optionally, the transition between the tooth top and tooth root of the spline tooth is provided with a chamfer, and the radius of the chamfer is 0.3-0.8mm; the tooth surface of the spline tooth is provided with a friction-reducing groove, and the depth of the friction-reducing groove is 0.05-0.1mm, which is used to reduce cutting resistance and improve the processing surface quality.

[0015] Optionally, the rake face of the chip dividing groove of the circular calibration tooth is treated with a hard alloy coating, the thickness of the hard alloy coating is 2-5 μm, and the hard alloy coating is made of TiAlN or TiCN to improve wear resistance and cutting performance.

[0016] Optionally, a micro texture is provided on the tooth surface of the spline tooth part, and the micro texture is periodically arranged pits or stripes, the pits have a depth of 3-8 μm and a diameter of 20-50 μm, which are used to store cutting fluid and improve cutting conditions; or the stripes have a depth of 5-10 μm, a width of 30-60 μm, and an inclination angle of 30-60 degrees.

[0017] The embodiments of the present application have the following beneficial effects:

[0018] 1) By providing chip-dividing grooves on the circular calibration teeth and staggering the chip-dividing grooves of two adjacent rows of calibration teeth, the iron chips can be broken and curled, avoiding the generation of continuous ring-shaped iron chips, thus eliminating the need for manual cleaning of iron chips and improving processing efficiency;

[0019] 2) Since the spline tooth can remove the mark left on the workpiece surface by the chip breaker groove, the surface finish of the final workpiece is not affected;

[0020] 3) The size of the chip breaker groove of the round alignment tooth is smaller than that of the round cutting tooth, and a specific inclination angle is adopted, so that the breaking and curling of the iron filings can be better controlled;

[0021] 4) By setting micro-texture and friction-reducing groove on the surface of the spline tooth, and coating the rake face of the chip breaker groove, the cutting conditions are further improved, and the machining quality is improved. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiments will be briefly introduced as follows:

[0023] Figure 1 is the overall structure schematic diagram of the composite spline broach provided by the present application;

[0024] Figure 2 is the cross-sectional view of A-A in Figure 1 , showing the chip breaker groove structure of the round cutting tooth;

[0025] Figure 3 is the cross-sectional view of B-B in Figure 1 , showing the chip breaker groove structure of the round alignment tooth and its staggered arrangement mode;

[0026] Figure 4 is the chamfer and friction-reducing groove structure schematic diagram of the spline tooth.

[0027] In the drawings:

[0028] 1-round cutting tooth part; 11-round rough cutting tooth; 12-round finish cutting tooth; 13-round alignment tooth;

[0029] 2-spline tooth part; 21-spline tooth;

[0030] 4-chip breaker groove; DETAILED DESCRIPTION

[0031] The technical solutions of the present application will be further described in detail below in combination with the drawings. In the description of the drawings, it should be noted that the terms "center", "vertical", "horizontal", "upper", "lower", "front", "rear", etc. indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore cannot be understood as a limitation on the present application.

[0032] As Figure 1As shown, the composite spline broach provided by the embodiment of the present application comprises a round cutting tooth part 1 and a spline tooth part 2. The round cutting tooth part 1 comprises a round rough cutting tooth 11, a round finish cutting tooth 12 and a round calibration tooth 13 arranged in sequence from front to back. The total length of the round cutting tooth part 1 can be 80-120mm, the axial length of the round rough cutting tooth 11 is 30-50mm, the axial length of the round finish cutting tooth 12 is 20-30mm, and the axial length of the round calibration tooth 13 is 30-40mm.

[0033] According to an embodiment of the present application, the first parting groove is arranged on the round rough cutting tooth 11 and the round finish cutting tooth 12. Figure 2 As shown, the width of the first parting groove is 0.5-1.0mm, and the depth is 0.5-1.2mm. The first parting groove penetrates the cutting edge, and is used to break and curl the iron filings during cutting. The cross section of the first parting groove and the parting groove 4 are both V-shaped, and the bottom of the V-shaped groove is provided with a circular arc transition, and the radius of the circular arc transition is 0.2-0.5mm. The circular arc transition structure at the bottom of the groove can enhance the strength of the parting groove, avoid stress concentration, effectively prolong the service life of the broach, and at the same time can improve the flow state of the cutting chip, so that the cutting chip is more easily broken and curled.

[0034] According to an embodiment of the present application, the number of teeth of the round rough cutting tooth 11, the round finish cutting tooth 12 and the round calibration tooth 13 increases in sequence. Specifically, the difference in the number of diameters between adjacent tooth rows is 0.01-0.08. The number of teeth of the round rough cutting tooth 11 is 6-12, the number of teeth of the round finish cutting tooth 12 is 3-5, and the number of teeth of the round calibration tooth 13 is 3-5. The gradual increase in the diameter can make the cutting load uniformly distributed, and improve the stability of the broaching process.

[0035] The core of the present application lies in the structural design of the round calibration tooth 13. As shown, Figure 3 The round calibration tooth 13 comprises two rows of calibration teeth arranged in front and back, and each row of calibration tooth is provided with a parting groove 4. The parting groove 4 is arranged at the middle part of the tooth thickness of the spline tooth 21, and the parting grooves 4 of the adjacent two rows of calibration teeth are arranged in the circumferential direction. Compared with the first parting groove, the size of the parting groove 4 is smaller, the width is 0.5-1.0mm, the depth is 0.3-0.8mm, and the opening inclination angle is 30-60 degrees. Through this design, the iron filings generated during the cutting of the round calibration tooth 13 can be broken and curled along the direction of the parting groove 4, avoiding the generation of continuous ring-shaped iron filings. At the same time, due to the small size of the parting groove 4 and the staggered arrangement in the circumferential direction, the influence on the workpiece surface can be reduced. Further, the included angle between the groove bottom surface of the parting groove 4 and the broach radial center line is 15-30 degrees, and this inclination angle design is conducive to adjusting the flow direction of the iron filings and controlling the curling diameter of the iron filings.

[0036] To further enhance cutting performance, the rake face of the chip splitter 4 in the embodiment of the present application is treated with a cemented carbide coating. The cemented carbide coating has a thickness of 2-5 μm and can be made of TiAlN or TiCN. This coating not only enhances the wear resistance of the chip splitter 4 but also improves its cutting performance and service life.

[0037] The axial length of the spline tooth part 2 is 200-600mm, and includes 30-120 equally spaced spline teeth 21. The spline teeth 21 are arranged parallel to the axis of the broach, and the transition between the tooth top and the tooth root is provided with a rounded corner (such as Figure 4 ), the radius of the fillet is 0.3-0.8mm. This fillet design can avoid stress concentration and improve the strength of the spline teeth 21.

[0038] In a preferred embodiment of the present application, the fillet radius at the transition between the tooth top and the tooth root of the spline tooth 21 is 0.3-0.8 mm, and a friction-reducing groove is provided on the tooth surface, and the depth of the friction-reducing groove is 0.05-0.1 mm. By setting a suitable fillet radius, stress concentration at the tooth top and the tooth root can be avoided, and the strength and durability of the spline tooth can be improved. The provision of the friction-reducing groove can reduce the friction resistance during the cutting process, reduce the generation of cutting heat, and thus improve the surface quality of the workpiece. In addition, a microstructure is also provided on the tooth surface of the spline tooth portion 2. The microstructure can take two forms: one is a periodically arranged pit with a depth of 3-8 μm and a diameter of 20-50 μm; the other is a stripe with a depth of 5-10 μm, a width of 30-60 μm, and an inclination angle of 30-60 degrees. These microtextures can store cutting fluid, improve cutting conditions, and further improve processing quality.

[0039] In actual application, when the composite spline broach is performing broaching, the circular rough cutting teeth 11 are first used for rough machining to remove most of the material of the workpiece. At this time, the first chip groove can break and curl the iron chips generated by cutting to facilitate discharge. Then the circular fine cutting teeth 12 are used for fine machining to further improve the dimensional accuracy and surface quality of the inner hole of the workpiece. Finally, the circular calibration teeth 13 perform the final calibration. Due to the design of the staggered chip grooves 4, the iron chips generated during the calibration process can also be broken and curled, without the need for manual cleaning. At the same time, the subsequent spline teeth 21 will remove the traces left by the chip grooves 4 on the workpiece surface when machining the spline grooves, thereby ensuring the surface finish of the final workpiece.

[0040] The composite spline broaches of the present invention address the problem of circular calibration teeth generating continuous rings of iron chips in the prior art by providing staggered chip-splitting grooves on the circular calibration teeth, using specific size and angle parameters. Furthermore, optimized designs such as friction-reducing grooves, microstructures, and a carbide coating further enhance the broach's machining performance. This composite spline broach not only improves machining efficiency and reduces manual intervention, but also ensures workpiece quality, possessing significant practical value.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A composite spline broach, characterized in that: include: a circular cutting tooth portion and a spline tooth portion, wherein the circular cutting tooth portion comprises a circular rough cutting tooth, a circular fine cutting tooth and a circular calibration tooth which are arranged in sequence; The circular calibration teeth include two rows of calibration teeth arranged adjacent to each other in front and back, and each row of the calibration teeth is provided with a chip groove, and the chip groove is arranged in the middle part of the tooth thickness of the spline teeth. The chip grooves of the two adjacent rows of calibration teeth are staggered in the circumferential direction so that the iron chips are broken and curled along the direction of the chip groove during the cutting process.

2. The composite spline broach according to claim 1, characterized in that: The circular rough cutting teeth and the circular fine cutting teeth are both provided with a first chip dividing groove, the width of the first chip dividing groove is 0.5-1.0mm, and the depth is 0.5-1.2mm; the chip dividing groove on the circular calibration tooth is 0.4-1.2mm in width, 0.3-0.8mm in depth, and the opening inclination angle is 30-60 degrees, which is used to control the curling degree of the iron chips.

3. The composite spline broach according to claim 2, characterized in that: The total length of the circular cutting tooth portion is 80-120 mm, wherein the axial length of the circular rough cutting teeth is 30-50 mm, the axial length of the circular fine cutting teeth is 20-30 mm, and the axial length of the circular calibration teeth is 30-40 mm.

4. The composite spline broach according to claim 3, characterized in that: The number of teeth of the circular rough cutting teeth is 6-10, the number of teeth of the circular fine cutting teeth is 2-4, and the number of teeth of the circular calibration teeth is 4-6.

5. The composite spline broach according to claim 4, characterized in that: The axial length of the spline tooth portion is 200-600 mm, and includes 30-120 equally spaced spline teeth, and the spline teeth are arranged parallel to the axis of the broach.

6. The composite spline broach according to claim 5, characterized in that: The cross-sections of the first chip dividing groove and the chip dividing groove are V-shaped, the groove bottom of the V-shaped groove is in an arc transition, and the radius of the groove bottom arc is 0.2-0.5mm, so as to enhance the strength of the chip dividing groove and extend the service life.

7. The composite spline broach according to claim 6, characterized in that: The angle between the bottom surface of the chip groove of the circular calibration tooth and the radial center line of the broach is 15-30 degrees, which is used to adjust the flow direction and curling diameter of the iron chips.

8. The composite spline broach according to claim 7, characterized in that: The transition between the tooth top and tooth root of the spline teeth is provided with a chamfer, and the radius of the chamfer is 0.2-0.5mm; the tooth surface of the spline teeth is provided with a friction-reducing groove, and the depth of the friction-reducing groove is 0.05-0.1mm, which is used to reduce cutting resistance and improve the processing surface quality.

9. The composite spline broach according to claim 8, characterized in that: The rake face of the chip groove of the circular calibration tooth is treated with a hard alloy coating. The thickness of the hard alloy coating is 2-5 μm. The hard alloy coating is made of TiAlN or TiCN to improve wear resistance and cutting performance.

10. The composite spline broach according to claim 9, characterized in that: A microstructure is provided on the tooth surface of the spline tooth part, and the microstructure is periodically arranged pits or stripes, the depth of the pits is 3-8μm, the diameter is 20-50μm, and it is used to store cutting fluid and improve cutting conditions; or the stripes are 5-10μm deep, 30-60μm wide, and have an inclination angle of 30-60 degrees.

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