A new type of spiral groove hard alloy reaming tool and its efficient chip removal structure

Abstract

The present application relates to the technical field of metal cutting tools, in particular to a novel spiral flute hard alloy reaming tool and its efficient chip removal structure, comprising a reamer and a main cutting edge arranged at the bottom of the reamer, a cutting group arranged at the lower part of the reamer, the cutting group comprising two chip removal grooves one and two arranged around the surface of the reamer, the size of the chip removal groove one being larger than that of the chip removal groove two; wherein: the height of the edge is lower than the secondary cutting edge, and the secondary cutting edge and the edge form an inclined plane angle alpha for assisting the sliding of the chips into the chip removal groove two; the secondary cutting edge is flush with the surface of the reamer and is aligned with the two ends of the main cutting edge, through the angle alpha design between the edge and the secondary cutting edge of the chip removal groove one, cooperating with the stepped structure that the edge is lower than the secondary cutting edge, the retention space of the chips in the transition area is completely eliminated, and the spiral scratches caused by the chips scraping of the traditional tool are avoided, providing a high-precision reference surface for subsequent tapping.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metal cutting tools, in particular to a new type of spiral groove hard alloy reaming tool and its efficient chip removal structure. BACKGROUND

[0002] The reamer is a rotating tool with one or more teeth to remove a thin layer of metal from the surface of a machined hole. The reamer is a rotating finishing tool with straight or spiral blades, used for hole expansion or hole repair.

[0003] The traditional reaming tool generally adopts a whole vertical chip removal groove structure design, and the main cutting edge and the secondary cutting edge are distributed in steps along the tool axis: the main cutting edge undertakes the main cutting task, and forms an initial hole type on the workpiece through spiral feeding motion, while the secondary cutting edge follows closely behind and realizes hole diameter calibration and surface finishing by precise fitting with the hole wall, providing a reference hole wall meeting the tolerance requirements for the subsequent tapping process.

[0004] In the actual reaming process, the main cutting edge will leave metal burrs on the hole wall after cutting, accompanied by a large amount of small particle fine chips. The secondary cutting edge of the traditional reaming tool is designed to be flush with the tool surface, i.e. without height difference or flow guide slope, and the junction between the secondary cutting edge and the chip removal groove forms a right angle transition zone. The structure of this area is closed, resulting in the retention of chips. When the secondary cutting edge finishes the hole wall, some fine chips will be squeezed and embedded in the gap between the edge of the secondary cutting edge and the chip removal groove. The vertical chip removal groove lacks directional flow guiding ability and cannot remove these chips in time. As the reaming tool continues to rotate, the retained chips will be rotated by the tool surface and will slide relative to the hole wall, causing continuous scratching of the hole wall by the edges of the chips, forming spiral scratches. Such scratches have a great impact on the subsequent tapping process. When the tap is inserted into the hole wall with scratches, stress concentration will occur at the intersection of the thread profile and the scratches, causing the collapse of the tooth top. If the depth of the scratches is deep, it will cause the deviation of the thread diameter, resulting in poor tapping caused by scratches, which may cause the loosening of the bolt connection and safety accidents.

[0005] Therefore, there is an urgent need for a new type of spiral groove hard alloy reaming tool and its efficient chip removal structure to improve the shortcomings of the prior art. SUMMARY

[0006] The present application aims to provide a new type of spiral groove hard alloy reaming tool and its efficient chip removal structure. By designing the included angle alpha between the edge of the chip removal groove and the secondary cutting edge, and combining the stepped structure with the edge lower than the secondary cutting edge, the retention space of the chips in the transition area is completely eliminated, avoiding the spiral scratches caused by the chips scratching of the traditional tool, and providing a high-precision reference surface for the subsequent tapping, to solve the problems raised in the above background technology, i.e.

[0007] Traditional reaming tools form a closed right-angle transition zone due to the flush design of the secondary cutting edge and the chip flute, which causes debris to be retained and scratch the hole wall when the tool rotates. These scratches can cause stress concentration, tooth crest collapse or diameter deviation during subsequent tapping, and even safety accidents due to loose connections.

[0008] To achieve the above object, the application provides a new type of spiral flute hard alloy reaming tool and its efficient chip removal structure, which comprises a reamer and a main cutting edge arranged at the bottom of the reamer, wherein the lower part of the reamer is provided with a cutting group, the cutting group comprises two chip flutes, i.e. chip flute one and chip flute two,

[0009] The size of the chip flute one is larger than that of the chip flute two;

[0010] A secondary cutting edge and an edge are arranged between the chip flute one and the chip flute two, the secondary cutting edge is located at the lower notch of the chip flute two, and the edge is located at the upper port of the chip flute one, wherein:

[0011] The height of the edge is lower than that of the secondary cutting edge, and an inclined surface with an angle a is formed between the secondary cutting edge and the edge to assist the sliding of the debris into the chip flute two;

[0012] The secondary cutting edge is flush with the surface of the reamer and aligned with the two ends of the main cutting edge.

[0013] In the above technical solution, the reamer realizes efficient machining through the double-chip flute design of the lower cutting group, the larger chip flute one cooperates with the main cutting edge to complete the main cutting operation, and the secondary cutting edge of the chip flute two synchronously polishes the hole wall, which is flush with the surface of the reamer and aligned with the two ends of the main cutting edge, ensuring the polishing accuracy; the angle a between the edge at the upper port of the chip flute one and the secondary cutting edge eliminates the debris retention space, avoiding the scratch of the hole wall caused by the debris driven by the tool rotation, and the structure that the edge is lower than the secondary cutting edge makes the chip flute two form an auxiliary flow channel and a local low-pressure area, when the chip flute one is partially blocked, the siphon effect generated by the low-pressure area can drive the debris to be directionally discharged through the chip flute two, realizing the coordinated and efficient cutting, polishing and chip removal.

[0014] On this basis, when the reamer is working, the main cutting edge at the lower end is flush with the outer peripheral surface, and the debris generated by cutting can directly enter the larger chip flute one and be directionally discharged towards the tail along the spiral path; the chip flute one and the chip flute two form a hierarchical chip removal structure with a 2:1 notch width ratio and a 0.5-1mm slot depth difference, large-particle debris is preferentially discharged through the chip flute one, and the chip flute one and the chip flute two decrease the slot depth and cross-sectional area at a shrinkage rate of 15%-20% per 10mm length from the cutting area to the tail, and the negative pressure suction effect is generated by the cross-sectional shrinkage to accelerate the flow of debris towards the tail.

[0015] The angle a between the upper end edge of the first chip removal groove and the secondary cutting edge is 5-15 degrees, and the height difference is 0.2-0.5 mm, which avoids the accumulation of chips in the transition area and forms a local low-pressure area in the second chip removal groove; when the first chip removal groove is partially blocked, the low-pressure area generates a siphon effect to guide the fine chips to be discharged through the second chip removal groove, and the design that the secondary cutting edge is flush with the reamer surface can polish the hole wall, thereby realizing the cooperation of high-efficiency chip removal and high-quality machining.

[0016] In another technical solution, the reamer surface is provided with a wear-resistant coating, the end of the edge is provided with a circular arc transition structure to reduce the obstruction to the chips, the reamer body is made of a whole cemented carbide material, the spiral directions of the first chip removal groove and the second chip removal groove are the same, and the two chip removal grooves are alternately distributed on the reamer surface.

[0017] This technical solution, the reamer is made of a whole cemented carbide material, has high strength and high rigidity, and can withstand the cutting force and impact load in high-speed cutting; the wear-resistant coating on the surface can reduce wear during cutting, maintain the cutting edge accuracy and service life. The first chip removal groove and the second chip removal groove with the same spiral direction are alternately distributed on the reamer surface, forming an orderly chip removal channel, so that the chips flow along a unified spiral path, avoiding chip removal disorder. At the same time, the end of the edge of the first chip removal groove is provided with a circular arc transition structure, which eliminates the right-angle obstruction and allows the chips to smoothly pass through the edge area into the chip removal groove, further improving the chip removal smoothness, and cooperating with the alternating groove design, realizing the synergistic effect of uniform dispersion of cutting force and efficient chip removal.

[0018] Compared with the prior art, the beneficial effects of the present application are:

[0019] The novel spiral groove cemented carbide reaming tool and the efficient chip removal structure thereof completely eliminate the retention space of the chips in the transition area through the angle a design between the edge of the first chip removal groove and the secondary cutting edge, and the stepped structure that the edge is lower than the secondary cutting edge, avoiding the spiral scratches caused by the chip scraping of the traditional tool, and providing a high-precision reference surface for subsequent tapping;

[0020] The size-differentiated double-chip removal groove design forms a primary and secondary shunt channel, and the large-particle chips generated by the primary cutting edge can be quickly discharged through the first chip removal groove; at the same time, the local low-pressure area formed by the height difference of the edge of the second chip removal groove can guide the fine chips to be discharged in a directional manner through the siphon effect when the first chip removal groove is partially blocked, so that the chip removal efficiency is improved;

[0021] The improvement of the chip removal smoothness reduces the friction and impact of the chips on the cutting edge, and the reduced cutting resistance of the double-groove shunt reduces the wear rate of the primary cutting edge and the secondary cutting edge, thereby prolonging the service life of the reamer. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1The overall structure schematic diagram of the embodiment;

[0023] Figure 2 The front view structure schematic diagram of the reamer of the embodiment;

[0024] Figure 3 The spiral partial enlarged structure schematic diagram of the embodiment;

[0025] Figure 4 The bottom view structure schematic diagram of the reamer of the embodiment;

[0026] Figure 5 The flute one and flute two pitch structure schematic diagram of the embodiment.

[0027] The meanings of various labels in the figure are as follows:

[0028] 100, reamer;

[0029] 110, clamping part; 111, anti-skid notch;

[0030] 120, cutting group; 121, flute one; 122, flute two; 123, sub cutting edge; 124, edge; 130, main cutting edge. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0032] For the conventional reamer, the sub cutting edge 123 is flush with the flute, forming a closed right angle transition zone, which causes the debris to be retained and scraped along the hole wall to produce scratches during the rotation of the tool. These scratches can cause stress concentration, tooth top collapse or diameter deviation during subsequent tapping, and even cause safety accidents due to loose connection. Please refer to Figures 1-5 The present embodiment provides a new spiral flute hard alloy reamer and its efficient chip removal structure, which comprises a reamer 100 and a main cutting edge 130 arranged at the bottom of the reamer 100. The lower part of the reamer 100 is provided with a cutting group 120, which comprises two flutes one 121 and two flutes two 122 arranged around the surface of the reamer 100,

[0033] The size of the flute one 121 is larger than that of the flute two 122;

[0034] The secondary cutting edge 123 is located at the lower notch of the second chip flute 122, and the edge 124 is located at the upper port of the first chip flute 121, wherein:

[0035] The height of the edge 124 is lower than that of the secondary cutting edge 123, and the secondary cutting edge 123 and the edge 124 form an inclined angle α for assisting the chips to slide into the second chip flute 122;

[0036] The secondary cutting edge 123 is flush with the surface of the reamer 100 and aligned with both ends of the main cutting edge 130.

[0037] In implementation, the new spiral flute hard alloy reaming tool realizes efficient chip removal and scratch prevention through the double-chip flute structure of the lower cutting group 120, as follows:

[0038] The first chip flute 121 with larger size is the main chip removal channel, and cooperates with the second chip flute 122 with smaller size to form a staged chip removal system.

[0039] The secondary cutting edge 123 at the lower notch of the second chip flute 122 is flush with the surface of the reamer 100 and aligned with both ends of the main cutting edge 130, which can polish the hole wall.

[0040] The angle α between the edge 124 at the upper port of the first chip flute 121 and the secondary cutting edge 123, combined with the height difference between the edge 124 and the secondary cutting edge 123, eliminates the jamming area of the chips in the transition area and avoids the scratch of the hole wall by the chips rotating with the tool.

[0041] At the same time, when the cooling fluid carrying the chips flows from the deep groove area of the inlet of the second chip flute 122 to the narrow outlet shallow groove area, the fluid cross-sectional area decreases, causing the flow rate to increase sharply, and then the fluid static pressure in this area decreases significantly, forming a local low-pressure area, which produces strong suction force on the chips and fluid. When the first chip flute 121 is partially blocked, a pressure difference is formed between the first chip flute 121 and the second chip flute 122, causing the cooling fluid to carry the chips along the area between the edge 124 and the secondary cutting edge 123 to the second chip flute 122 for directional discharge, ensuring that the chips are removed in time during the cutting process.

[0042] Referring to Figure 2As shown, the reamer 100 is made of tungsten carbide alloy material, and the clamping portion 110 at the upper portion of the reamer 100 is connected with the output end of the electric drill through the anti-skid groove 111 extending downward along the outer surface in the axial direction, and the protrusion of the output end connection port of the electric drill is matched with the anti-skid groove 111, so that the tool is prevented from relative sliding during high-speed rotation cutting. Meanwhile, the two spiral chip removal grooves cooperatively realize the chip removal function: the chip removal groove one 121 with larger size serves as a main chip removal channel, and can accommodate and guide more cutting chips, and the chip removal groove two 122 with smaller size serves as an auxiliary channel, and cooperates to complete the chip removal, so as to improve the overall chip removal efficiency through the differentiated size design, and ensure the stable cutting process.

[0043] Figure 3 In the embodiment, the edge 124 at the upper port of the chip removal groove one 121 and the secondary cutting edge 123 are arranged at an angle a of 5°-15° with respect to the vertical line. When the chips are removed along the spiral groove under the driving of the cooling liquid, the chips will be thrown outward to the hole wall under the action of centrifugal force. The inclined flow guide surface with the angle a of 5-15 degrees can generate a centripetal force directed to the tool axis for the flowing chips and cooling liquid. This force effectively offsets the centrifugal effect, forces the chip to shrink inwardly tightly adhering to the flow guide surface, so as to completely avoid the friction and scraping of the chips with the machined hole wall, and ensures the surface quality of the hole. If the angle is less than 5 degrees, the guiding force is insufficient, and if the angle is greater than 15 degrees, the chip removal resistance will be significantly increased and even lead to blockage.

[0044] Meanwhile, the radial height of the edge 124 is lower than that of the secondary cutting edge 123 by 0.2-0.5 mm. If the height difference is less than 0.2 mm, the heat deformation or chip accumulation may rub against the hole wall, and if the height difference is greater than 0.5 mm, the chips lose the guidance constraint and are easy to separate from the guide surface and lose the effective guidance.

[0045] When the fine chips generated by the secondary cutting edge 123 for hole wall polishing move to the chip removal groove two 122 under the action of centrifugal force, the inclined surface formed by the angle a forces the chips to slide into the cavity of the chip removal groove two 122 along the predetermined track, and the height difference between the edge 124 and the secondary cutting edge 123 completely eliminates the chip retention caused by the traditional right angle. This structure ensures that the chips timely separate from the secondary edge area, and avoids the hard chips from pressing the hole wall during rotation.

[0046] In addition, referring to Figure 3As shown, based on the design of the flute one 121 and the flute two 122, the cross-sectional area of the double flute decreases gradually from the cutting zone to the tail, forming an accelerating channel when the liquid flows. Under normal working conditions, the large cross-section of the flute one 121 dominates the chip removal, and the flute two 122 is responsible for guiding the small particles. When the flute one 121 is blocked, the coolant and chips generated in the cutting zone cannot be discharged through the main channel. At this time, the flute two 122 acts as an auxiliary channel. The gradually decreasing cross-sectional area from the cutting zone to the tail of the flute two 122 significantly increases the flow rate of the coolant due to space compression. The continuous flute two 122 generates a local low pressure in the slot area due to the contraction of the cross-sectional area, triggering the siphon effect to press the coolant into the flute two 122, forming a continuous suction effect, and the retained chips are carried along the spiral path of the flute two 122, so that the tool still maintains the chip removal function under extreme conditions, reducing the probability of abnormal downtime caused by chip blocking.

[0047] Referring to Figure 4 As shown, during operation of the reaming tool, the main cutting edge 130 at the lower end is flush with the outer surface of the reamer 100 and directly contacts the workpiece during reaming to cut chips, which can smoothly enter the flute one 121 and be directed to the tail of the reamer 100 along the spiral path of the flute one 121, avoiding chip accumulation in the cutting zone.

[0048] At the same time, the surface of the reamer 100 is coated with a titanium-based wear-resistant coating according to the prior art, which improves the surface hardness of the drill bit and reduces wear on the cutting edge and surface during cutting, greatly extending the time the main cutting edge 130 can remain sharp and ensuring cutting efficiency.

[0049] Referring to Figure 5 As shown, during operation of the reamer 100, the two flutes of the lower cutting group 120 work together to achieve a staged chip removal function: the larger flute one 121 acts as the main chip removal channel, responsible for guiding the main cutting chips, while the smaller flute two 122 acts as an auxiliary channel, diverting some fine chips. The two flutes are distributed around the surface of the reamer 100, forming a complementary chip removal system to prevent congestion in a single flute during high-load cutting.

[0050] The flute one 121 and the flute two 122 have a slot width ratio of W1:W2=2:1 and a slot depth difference of 0.5-1mm to form a staged chip removal structure: the flute one 121 can quickly accommodate and guide a large number of main cutting chips due to its larger chip space and flow cross-section; the flute two can achieve directional flow of small particle chips through the design of a narrow slot and shallow slot depth. This size-differentiated optimization design not only ensures the functional division of the primary and secondary chip removal channels, but also improves the overall chip removal efficiency through synergistic effect, effectively reducing the probability of chip retention on the tool surface.

[0051] The new type of spiral groove hard alloy reaming tool and its efficient chip removal structure in this embodiment, first, the lower cutting group 120 of the reamer 100 contains two spiral chip removal grooves with different sizes: the larger size chip removal groove one 121 and the smaller size chip removal groove two 122. The lower groove opening of the chip removal groove two 122 is provided with a secondary cutting edge 123 flush with the surface of the reamer 100 and aligned with the two ends of the main cutting edge 130. The included angle α between the upper port edge 124 of the chip removal groove one 121 and the secondary cutting edge 123 ensures that the chips cut from the hole wall cannot wedge or be stuck in the narrow area between the secondary cutting edge 123 and the edge 124, completely eliminating the chip retention phenomenon that may occur at this point in the traditional design, thereby effectively preventing the scratch of the processed hole wall caused by the stuck chips during tool rotation, and significantly improving the surface quality.

[0052] At the same time, the height of the edge 124 is 0.2-0.5mm lower than that of the secondary cutting edge 123, and the smaller size chip removal groove two 122, combined with the height difference between the groove opening secondary cutting edge 123 and the edge 124 of the chip removal groove one 121, naturally forms an auxiliary flow channel under low pressure and siphon phenomenon. When the machining process encounters increased chip removal resistance such as chip winding or viscous material causing partial blockage or poor chip removal of the main chip removal groove one 121, a lower air pressure space than the chip removal groove one 121 will be generated under the flow of cooling liquid in the chip removal groove two 122. The blocked chips and cooling liquid are sucked and driven through the standby channel of the chip removal groove two 122 to be directed out, realizing cooperative chip removal and greatly enhancing the reliability and adaptability of chip removal in harsh working conditions.

[0053] The upper part of the tool is provided with a clamping part 110 with an axial anti-slip groove opening 111 to enhance the clamping stability. The main cutting edge 130 at the end of the reamer 100 is flush with the surface, and the generated chips are mainly discharged along the spiral path of the chip removal groove one 121 to the tail. The two chip removal grooves have the same spiral direction and are alternately distributed, and the width and depth of the chip removal groove one 121 are significantly greater than those of the chip removal groove two 122, the width ratio is about W1:W2=2:1, the depth difference is 0.5-1mm, and from the cutting area to the tail, the depth of the two grooves gradually decreases, and the opening cross-sectional area shrinks at a rate of 15%-20% per 10mm length, which helps to guide the smooth flow of chips and prevent accumulation in the groove. Moreover, as the chips move backward, the shrinking structure naturally exerts a certain extrusion and guiding effect on the chips, and in combination with the surface wear-resistant coating and the circular arc transition at the end of the edge 124, it ensures that the chips can be continuously, quickly and low-resistance discharged from the machining area, and finally realizes efficient, stable and high-quality reaming machining.

[0054] The above shows and describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited to the above-mentioned embodiments, and the above-mentioned embodiments and descriptions in the specification are only preferred examples of the present application and are not intended to limit the present application. Various changes and improvements can be made to the present application without departing from the spirit and scope of the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A novel helical groove carbide reaming tool and its efficient chip removal structure, comprising a reamer (100) and a main cutting edge (130) disposed at the bottom of the reamer (100), wherein the lower part of the reamer (100) is provided with a cutting assembly (120), the cutting assembly (120) comprising two chip removal grooves, a first chip removal groove (121) and a second chip removal groove (122), which are helically oriented in the same direction and alternately distributed around the surface of the reamer (100), characterized in that: The ratio of the width of the opening of the first chip removal groove (121) to the width of the opening of the second chip removal groove (122) is 2:1, and the depth of the first chip removal groove (121) is 0.5-1mm greater than that of the second chip removal groove (122). A secondary cutting edge (123) and an edge (124) are provided between the first chip removal groove (121) and the second chip removal groove (122). The secondary cutting edge (123) is located at the lower opening of the second chip removal groove (122), and the edge (124) is located at the upper opening of the first chip removal groove (121). The height of the edge (124) is 0.2-0.5 mm lower than that of the secondary cutting edge (123), and a 5°-15° inclined plane angle α is formed between the secondary cutting edge (123) and the edge (124) to guide the chips away from the hole wall and slide into the chip removal groove (122); the depth of the chip removal groove (121) and the chip removal groove (122) gradually decreases from the cutting area to the tail of the reamer (100), and the cross-sectional area of ​​the groove opening shrinks synchronously at a shrinkage rate of 15%-20% per 10 mm of length; Chip removal groove one (121) is the main chip removal channel, through which large chips generated by the main cutting edge (130) are discharged; chip removal groove two (122) is an auxiliary channel used to divert some fine chips. When a partial blockage occurs in chip removal groove one (121), a pressure difference is formed between chip removal groove one (121) and chip removal groove two (122), causing coolant carrying debris to flow along the area between the edge (124) and the secondary cutting edge (123) into chip removal groove two (122) for directional discharge.

2. The novel spiral groove cemented carbide reaming tool and its high-efficiency chip removal structure according to claim 1, characterized in that: The upper part of the reamer (100) is provided with a clamping part (110) for clamping, and the outer surface of the clamping part (110) is provided with an anti-slip groove (111) extending downward along the axial direction of the reamer (100).

3. The novel spiral groove cemented carbide reaming tool and its high-efficiency chip removal structure according to claim 1, characterized in that: The surface of the reamer (100) is provided with a wear-resistant coating.

4. The novel spiral groove cemented carbide reaming tool and its high-efficiency chip removal structure according to claim 1, characterized in that: The end of the edge (124) is provided with a rounded transition structure, and the secondary cutting edge (123) and the edge (124) are integrally formed.

5. The novel spiral groove cemented carbide reaming tool and its high-efficiency chip removal structure according to claim 1, characterized in that: The reamer (100) body is made of cemented carbide material.

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