Expanding drill

Abstract

The expanding drill comprises an expanding drill body, a tool nose platform and a tail handle, a non-uniform stress field is formed in a cutting area through differential transverse section angles of a first transition blade and a second transition blade, cuttings are forced to be directionally bent and broken at the double transition blades, C-shaped broken cuttings are stably generated, and compared with a traditional design, the chip breaking point is uncontrollable, and the chip breaking rate is lt; 60%; according to the scheme, the chip breaking rate is gt; 95%; the axial directions of the three groups of chip flutes are designed at the same inclination angle, so that C-shaped chips are ensured to move along the uniform spiral direction; the first chip flute is used for receiving short chips generated in the center of a tool nose; the second chip flutes capture the middle parts of the C-shaped chips caving at the chip breaking points of the transition blades; the third chip flutes guide chip tails at the top ends of the second cutting edges to be discharged; the three-groove relay type chip removal eliminates chip flow interference and avoids winding a cutter.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of precision machining, more particularly to a reamer. BACKGROUND

[0002] Traditional reamer has two major pain points when machining ductile materials (such as stainless steel, superalloy): difficulty in chip breaking: long continuous chips wrap around the tool, requiring frequent downtime for cleaning, reducing machining efficiency; poor chip removal: existing chip flute structure is single, difficult to guide the chip to be directed out, easy to scratch the hole wall. Although individual solutions attempt to add a chip breaking table or complex flute type, for example, Patent No. CN216065692U, but often lead to: random chip breaking position, still producing irregular long chips; multi-flute angle difference causes chip removal path conflict, aggravating the risk of blockage.

[0003] Therefore, there is an urgent need for an integrated solution that can precisely control the chip breaking shape (such as C-shaped) and achieve directional chip removal. SUMMARY

[0004] The purpose of the present application is to provide a reamer, including a reamer body, a tool tip platform and a tail handle, by differentiating the horizontal cutting angle of the first and second transition edges, forming a non-uniform stress field in the cutting zone, forcing the chip to bend and break directionally at the double transition edges, and stably generating C-shaped chips. Compared with traditional design: chip breaking point is uncontrollable, chip breaking rate <60%; the chip breaking rate of the present solution is >95%; three groups of chip flutes are designed with the same inclination angle in the axial direction to ensure that the C-shaped chips move in a uniform spiral direction: the first chip flute receives the short chips generated by the tool tip center; the second chip flute captures the middle part of the C-shaped chips falling from the transition edge chip breaking point; the third chip flute guides the chip tail at the top end of the second cutting edge to be removed; three flute relay chip removal eliminates chip flow interference and avoids wrapping around the tool.

[0005] A reamer, comprising a reamer body, a nose platform and a shank, the rear end of the reamer body is connected with the front end of the shank, and the front end is connected with the rear end of the nose platform; the outer wall of the reamer body is provided with spiral-shaped chip flutes, and the adjacent chip flutes form a land; the nose platform is provided with a first cutting edge, the side of the land close to the chip flutes is provided with a second cutting edge, and the second cutting edge is connected with the first cutting edge at the head and tail; characterized in that: the first cutting edge is provided with a first transition edge and a second transition edge, the two transition edges have different horizontal cross-section angles and form a chip breaking stress concentration point, so that the chip is broken into a C shape and is easy to discharge; a first chip pocket communicating with the chip flutes is arranged between the center of the nose platform and the first transition edge; a second chip pocket communicating with the chip flutes is arranged between the first transition edge and the second transition edge; a third chip pocket communicating with the chip flutes is arranged between the second transition edge and the top end of the second cutting edge; the axial inclination angles of the first chip pocket, the second chip pocket and the third chip pocket are the same, the chip breaking stress point is accurately controlled by the differential angle of the double transition edges, the chip is forced to break into a C shape at a specific position, and directional guidance is realized by the directional guidance of the three groups of chip pockets with the same axial inclination angle, so that the integration of efficient chip breaking and directional chip discharge is realized, and the problem of long chip winding is solved.

[0006] Further, the groove bottom depths of the first chip pocket, the second chip pocket and the third chip pocket gradually decrease along the chip discharge direction, the gradient depth design matches the deformation amount when the chip is discharged, avoids the blockage of the chip pocket, and improves the smoothness of chip discharge.

[0007] Further, the inclination angle of the first cutting edge satisfies: the angle α from the center of the nose platform to the first transition edge section < the angle β from the first transition edge to the second transition edge section < the angle γ from the second transition edge to the top end of the second cutting edge, the three sections have increasing intensity angle design, the cutting resistance is gradually increased, stable chip breaking is realized by the transition edges, and the cutting heat load is dispersed.

[0008] Further, the second transition edge is connected with the top end of the second cutting edge, and a chamfer towards the top end of the second cutting edge is arranged at the connection position, the chamfer eliminates the stress concentration point, prevents the edge from being broken, and prolongs the tool life.

[0009] In some embodiments, the first cutting edge is connected with a relief angle on the side away from the chip flutes, the lower part of the relief angle is connected with the top part of the land, and an internal cooling hole penetrating through the reamer body to the shank is arranged in the relief angle, the internal cooling hole directly passes through the cutting area to realize targeted cooling and inhibit tool thermal deformation; the relief angle and the land are integrated to improve the structural rigidity.

[0010] Further, the relief angle is provided with a first avoidance position inclined to the land on the side away from the first cutting edge, so that the position of the outlet of the internal cooling hole is exposed, the avoidance position enlarges the spraying range of the cooling liquid, avoids the influence of the structure on the cooling efficiency, and reduces the tool mass.

[0011] In some embodiments, the land away from the second cutting edge side is provided with an auxiliary cutting edge, which enhances the radial support force, suppresses machining vibration and improves the hole wall quality.

[0012] In some embodiments, the reamer body is provided with a transition step at the connection with the shank, and the transition step is provided with an empty cutting groove on the connection side of the reamer body, which improves clamping stability and eliminates stress concentration to prevent root fracture.

[0013] The present application has the following beneficial effects: the present application provides a reamer, which includes a reamer body, a land and a shank, and forms a non-uniform stress field in the cutting area through the differential horizontal cross-section angles of the first and second transition edges, forces the chip to bend and break at the double transition edges, and stably generates C-shaped chips; compared with the traditional design, the chip breaking point is uncontrollable and the chip breaking rate is less than 60%; the chip breaking rate of the present application is greater than 95%; the three sets of chip grooves are designed with the same inclination angle in the axial direction to ensure that the C-shaped chips move in a unified spiral direction; the first chip groove receives the short chips generated by the center of the land; the second chip groove captures the middle part of the C-shaped chips falling from the chip breaking point of the transition edge; and the third chip groove guides the chip tail at the top end of the second cutting edge to discharge; the three-groove relay type chip removal eliminates chip flow interference and avoids winding the tool. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 Figure 1 is a structural schematic diagram of a reamer according to the present application.

[0015] Figure 2 Figure 2 is a schematic diagram of the tool head structure of a reamer according to the present application.

[0016] MAIN ELEMENT SYMBOL EXPLANATION

[0017] Reamer body 1, auxiliary cutting edge 10, transition step 11, empty cutting groove 12, land 2, first cutting edge 21, first transition edge 211, second transition edge 212, shank 3, chip removal groove 4, land 5, second cutting edge 51, first chip groove 61, second chip groove 62, third chip groove 63, clearance angle 7, internal cooling hole 8, chamfer 9.

[0018] The following specific embodiments will further illustrate the present application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0019] The following embodiments are described to assist in the understanding of the present application, and the embodiments are not and should not be interpreted as limiting the protection scope of the present application in any way.

[0020] In the following description, those skilled in the art will further recognize that the individual function units (which can include sub-units) can be described throughout this discussion as single function units, but those skilled in the art will recognize that the various function units, or portions thereof, can be divided into single function units, or can be integrated together, including integrated within a single system or component.

[0021] Also, connections between components or systems are not intended to be exclusive of each other but rather are intended to be illustrative of the various means by which the data can be communicated, modified, reformatted, or otherwise changed between the individual components. Embodiment 1

[0022] As shown in FIG. 1, it is a structural diagram of a reamer according to the present application; as shown in FIG. 2, it is a structural diagram of a cutter head of a reamer according to the present application. Figure 1 Figure 2 As shown in FIG. 1, it is a structural diagram of a reamer according to the present application; as shown in FIG. 2, it is a structural diagram of a cutter head of a reamer according to the present application.

[0023] ​The application discloses a reamer, which comprises a reamer body 1, a nose platform 2 and a shank 3, wherein the rear end of the reamer body 1 is connected with the front end of the shank 3, and the front end is connected with the rear end of the nose platform 2; the outer wall of the reamer body 1 is provided with spiral-shaped chip removal grooves 4, and the adjacent chip removal grooves 4 form a land 5; the nose platform 2 is provided with a first cutting edge 21, one side of the land 5 close to the chip removal groove 4 is provided with a second cutting edge 51, and the second cutting edge 51 is connected with the first cutting edge 21 in a head-to-tail mode; the first cutting edge 21 is provided with a first transition edge 211 and a second transition edge 212, the two transition edges have different horizontal cross-section angle and form a chip breaking stress concentration point, so that the chip is broken into a C shape; a first chip pocket 61 which is communicated with the chip removal groove 4 is arranged between the center of the nose platform 2 and the first transition edge 211; a second chip pocket 62 which is communicated with the chip removal groove 4 is arranged between the first transition edge 211 and the second transition edge 212; a third chip pocket 63 which is communicated with the chip removal groove 4 is arranged between the second transition edge 212 and the top end of the second cutting edge 51; the axial inclination angles of the first, second and third chip pockets 61, 62 and 63 are the same. The differential angle double transition edges accurately control the chip breaking stress point, force the chip to break into a C shape at a specific position, and realize the integration of efficient chip breaking and directional chip removal by cooperating with the directional guidance of the three groups of axial same-inclination chip pockets, so that the problem of long chip winding is solved; the groove bottom depths of the first, second and third chip pockets 61, 62 and 63 gradually decrease along the chip removal direction, the gradient depth design matches the deformation amount when the chip is discharged, avoids the chip pocket blockage, improves the chip removal smoothness, the rear angle 7 away from the first cutting edge 21 side is provided with a first avoidance position 71 which is inclined to the land 5, so that the outlet position of the internal cooling hole 8 is exposed, the avoidance position enlarges the cooling liquid injection range, avoids the structural shielding from affecting the cooling efficiency, simultaneously reduces the tool quality, and the top end connection position of the second transition edge 212 and the second cutting edge 51 is provided with a chamfer 9 which is directed to the top end of the second cutting edge 51, the chamfer 9 eliminates the stress concentration point, prevents the edge from being broken, and prolongs the tool life.

[0024] The inclination angle of the first cutting edge 21 satisfies that the angle from the center of the nose platform 2 to the first transition edge 211 is smaller than the angle from the first transition edge 211 to the second transition edge 212, and the angle from the second transition edge 212 to the top end of the second cutting edge 51 is the largest, three-section increasing strength angle design gradually increases the cutting resistance, and the transition edges realize stable chip breaking and simultaneously disperse the cutting heat load.

[0025] The first cutting edge 21 is connected with a clearance 7 away from the chip flute 4, the lower part of the clearance 7 is connected with the top of the land 5, and the clearance 7 is provided with an internal cooling hole 8 penetrating through the drill body 1 to the shank 3. The internal cooling hole 8 is straight through the cutting area, realizes targeted cooling, and inhibits tool thermal deformation; the clearance 7 is integrated with the land 5 to improve the structural rigidity; the land 5 is provided with an auxiliary cutting edge 10 away from the second cutting edge, the auxiliary cutting edge 10 enhances the radial support force, inhibits machining vibration, improves the hole wall quality; the drill body 1 is provided with a transition step 11 at the connection with the shank 3, and the transition step 11 is provided with an empty flute 12 at the connection with the drill body, the transition step improves the clamping stability, and the empty flute eliminates stress concentration and prevents root fracture.

[0026] Although the present application has disclosed multiple aspects and embodiments, other aspects and embodiments will be apparent to those skilled in the art, and several modifications and improvements can be made without departing from the concept of the present application, which all belong to the protection scope of the present application. The aspects and embodiments disclosed in the present application are only used for illustration, and are not intended to limit the present application, and the actual protection scope of the present application is subject to the claims.

Claims

1. A reamer, comprising a reamer body (1), a cutting edge platform (2), and a tail shank (3), wherein the rear end of the reamer body (1) is connected to the front end of the tail shank (3), and the front end is connected to the rear end of the cutting edge platform (2); the outer wall of the reamer body (1) is provided with a spiral chip removal groove (4), and a cutting back (5) is formed between adjacent chip removal grooves (4); the cutting edge platform (2) is provided with a first cutting edge (21), and the cutting back (5) is provided with a second cutting edge (51) on the side near the chip removal groove (4), and the second cutting edge (51) is connected end-to-end with the first cutting edge (21); characterized in that: The first cutting edge (21) is provided with a first transition edge (211) and a second transition edge (212). The two transition edges have different transverse cutting angles and form a chip breaking stress concentration point, causing the chip to break into a C-shape. The center of the tool tip platform (2) and the first transition edge (211) are provided with a first chip receiving groove (61) that connects to the chip removal groove (4). The first transition edge (211) and the second transition edge (212) are provided with a second chip receiving groove (62) that connects to the chip removal groove (4). The second transition edge (212) and the top of the second cutting edge (51) are provided with a third chip receiving groove (63) that connects to the chip removal groove (4). The first, second, and third chip receiving grooves (61, 62, 63) have the same axial inclination angle.

2. The reamer according to claim 1, characterized in that: The bottom depth of the first chip groove (61), the second chip groove (62) and the third chip groove (63) gradually decreases along the chip removal direction.

3. The reamer according to claim 1, characterized in that: The tilt angle of the first cutting edge (21) satisfies: the angle α from the center of the tool tip platform (2) to the first transition edge (211) < the angle β from the first transition edge (211) to the second transition edge (212) < the angle γ from the second transition edge (212) to the tip of the second cutting edge (51).

4. The reamer according to claim 1, characterized in that: The first cutting edge (21) is connected to a rear corner (7) on the side away from the chip groove (4). The lower part of the rear corner (7) is connected to the top of the back of the tool (5), and the rear corner (7) is provided with an internal cooling hole (8) that penetrates the main body (1) of the reamer to the tail shank (3).

5. The reamer according to claim 4, characterized in that: The back angle (7) is provided with a first clearance position (71) inclined towards the back of the tool (5) on the side away from the first cutting edge (21), so that the outlet position of the internal cooling hole (8) is exposed.

6. The reamer according to claim 1, characterized in that: The second transition edge (212) is provided with a chamfer (9) at the connection point between the tip of the second cutting edge (51) and the tip of the second cutting edge.

7. The reamer according to claim 1, characterized in that: The back of the blade (5) is provided with an auxiliary cutting edge (10) on the side away from the second cutting edge (51).

8. The reamer according to claim 1, characterized in that: The connection between the main body (1) and the tail shank (3) of the reamer is provided with a transition step (11), and a hollow tool groove (12) is opened on the side of the transition step (11) and the main body (1) of the reamer.

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