A PCD drill bit with a Y-shaped internal cooling channel

Abstract

A PCD drill bit with Y-shaped internal cooling hole relates to the technical field of drill bit. The PCD drill bit comprises a drill shank, a drill shaft and a drill tip. The drill tip is made of PCD material and is connected to the drill shaft. The drill tip is a multi-apex drill tip structure, and two spiral grooves are arranged in a first spiral direction. The drill shaft is provided with two chip removal curved surfaces connected to the two spiral grooves respectively. The spiral grooves and the chip removal curved surfaces are connected to form a spiral chip removal groove of the drill bit. The drill shank and the drill shaft are provided with cooling holes. The cooling holes are configured in a Y-shaped structure, and are provided with a cooling inlet, a cooling flow channel and two cooling outlets. The two cooling outlets are respectively connected to the two chip removal curved surfaces. The spiral chip removal groove is provided with a vein structure micro channel connected to the cooling outlet, so that the cooling liquid flows to the end of the drill tip. The side wall of the cooling flow channel is provided with a spiral rifling micro groove in a second spiral direction. The first spiral direction and the second spiral direction are opposite, so that the cooling liquid is further supplied to the drill tip through the spiral rifling micro groove when the spiral chip removal groove removes the chips.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of drill bits, in particular to a PCD drill bit with Y-shaped internal cooling hole. BACKGROUND

[0002] PCD drill bits are widely used in machining non-metallic materials such as non-ferrous metals, carbon fiber composites, ceramics, and quartz. During drilling, the traditional external cooling method cannot effectively deliver cooling liquid to the drilling area due to the semi-closed space of the drill bit, resulting in high concentration of cutting heat and poor chip removal. High cutting temperature accelerates the graphitization of diamond material, exacerbates tool wear, and shortens tool life. Meanwhile, the accumulation of chips in the spiral groove can scratch the machined surface, reducing the quality of the hole wall. The friction between the chips and the hole wall also generates secondary cutting heat, further deteriorating the cutting environment.

[0003] To improve cooling and chip removal, the prior art uses internal cooling, which sets up a cooling hole structure inside the drill bit. The cooling hole inlet is usually designed as a straight hole structure connected to the center hole of the spindle. The cooling hole flow channel adopts a cylindrical cross-sectional shape. The cooling hole outlet is set near the drill tip with a small diameter. This design aims to deliver cooling liquid directly to the machining area through the internal channel, reducing heat accumulation and chip accumulation.

[0004] However, the existing internal cooling hole design has obvious defects. The straight hole structure of the cooling hole inlet causes a sudden change in cross-section when the cooling liquid enters from the center hole of the spindle, resulting in a large flow rate loss, reducing the flow rate and flow rate of the cooling liquid. The cylindrical shape of the cooling flow channel causes the cooling liquid to vertically impact the hole wall under the action of centrifugal force during high-speed drilling, forming local turbulence and further causing flow rate loss, affecting cooling efficiency.

[0005] In addition, the cooling hole outlet has a small diameter, and the debris generated during drilling can easily adhere or tightly embed on the hole wall, blocking or closing the outlet, making it difficult for the cooling liquid to reach the drill tip machining area, and unable to achieve effective cooling and chip removal. SUMMARY

[0006] The present application provides a PCD drill bit with a Y-shaped internal cooling hole, aiming to improve at least one of the above technical problems.

[0007] To solve the above technical problems, the present application provides a PCD drill bit with a Y-shaped internal cooling hole, which comprises a drill shank, a drill rod and a drill tip. The drill tip is made of PCD material and is connected to the drill rod.

[0008] The drill tip is configured as a multi-top-angle drill tip structure and is provided with two spiral grooves in a first spiral direction. The drill rod is provided with two chip removal curved surfaces connected to the two spiral grooves respectively. The spiral groove and the chip removal curved surface are connected to form a spiral chip removal groove of the drill bit.

[0009] The drill shank and drill rod are provided with cooling holes. The cooling holes are Y-shaped and have a cooling inlet, a cooling channel, and two cooling outlets. The two cooling outlets are respectively connected to the two chip removal surfaces.

[0010] The spiral chip removal groove is provided with a vein-structured microchannel that connects to the cooling outlet, so that the coolant can flow to the end of the drill tip.

[0011] The sidewall of the cooling channel is provided with helical rifling microgrooves along the second helical direction. The first helical direction is opposite to the second helical direction, so that when the helical chip removal groove removes chips, the helical rifling microgrooves can further supply coolant to the drill tip.

[0012] As a further optimization, the leaf vein structure microchannel includes a main vein microchannel arranged along the spiral line of the spiral chip removal groove, and a first branch microchannel extending outward from the main vein microchannel. The main vein microchannel starts at the cooling outlet, extends along the middle of the spiral chip removal groove, and terminates in the machining area of ​​the drill tip. The first branch microchannel extends along the side of the spiral chip removal groove from the main vein microchannel to the back of the shovel next to the spiral chip removal groove.

[0013] As a further optimization, the leaf vein structure microchannel also includes a second branch microchannel extending outward from the main vein microchannel. The second branch microchannel extends along the side of the spiral chip removal groove, from the main vein microchannel to the back area of ​​the shovel next to the spiral chip removal groove.

[0014] The first branch microchannel and the second branch microchannel are spaced apart along the axis of the drill bit.

[0015] Each spiral chip removal groove is provided with one main pulse microchannel, two first branch microchannels, and two second branch microchannels. The two first branch microchannels are located on both sides of the main pulse microchannel. The two second branch microchannels are located on both sides of the main pulse microchannel.

[0016] As a further optimization, the angle between the first branch microchannel and the main pulse microchannel is 30 to 60 degrees. The angle between the second branch microchannel and the main pulse microchannel is 30 to 60 degrees. The width of the main pulse microchannel is 0.04 mm to 0.06 mm. The depth of the main pulse microchannel is 0.04 mm to 0.06 mm. The width of the first branch microchannel is 0.01 mm to 0.03 mm. The depth of the first branch microchannel is 0.01 mm to 0.03 mm. The width of the second branch microchannel is 0.01 mm to 0.03 mm. The depth of the second branch microchannel is 0.01 mm to 0.03 mm.

[0017] As a further optimization, the angle between the first branch microchannel and the main pulse microchannel is 45 degrees. The angle between the second branch microchannel and the main pulse microchannel is 45 degrees. The width and depth of the main pulse microchannel are both 0.05 mm. The width and depth of both the first branch microchannel and the second branch microchannel are both 0.02 mm.

[0018] As a further optimization, the number of helical rifling microgrooves is 4, 6, or 8, and they are arranged rotationally symmetrically. The helix angle of the helical rifling microgrooves is ≤15°.

[0019] The cross-sectional profile of the helical rifling microgrooves is rectangular. The raised portion of the helical rifling microgrooves is called the male groove, and its width is... The grooves in the spiral rifling are called recessed grooves, and their width is... The width of the bearish candlestick is greater than the width of the bullish candlestick. .

[0020] The difference in radius between the bullish and bearish candlesticks is called the rifling depth, and its depth is... Use rounded corners to connect the bearish and bullish candlesticks, with a radius of [missing information]. .

[0021] As a further optimization, the number of spiral grooves is 4. The helix angle of the rifling is a constant 10°.

[0022] Diameter of cooling channel The construction is 0.5mm, and the width and depth of the spiral groove rifling are both 0.025mm, so that the distance between the negative lines of two opposing spiral rifling microgrooves is... It is 0.55mm.

[0023] The spiral chip removal grooves spiral clockwise from the drill rod to the drill tip. The spiral rifling microgrooves spiral counterclockwise from the drill shank to the drill rod.

[0024] As a further optimization, the cooling inlet is constructed as a hyperbolic tapered inverted cone structure. The opening of the hyperbolic tapered inverted cone structure is used to connect with the central hole of the spindle, and the end of the hyperbolic tapered inverted cone structure is used to connect with the cooling channel, thereby increasing the flow rate and velocity of the coolant entering the cooling hole.

[0025] The model of the hyperbolic gradient inverted cone structure is as follows: .

[0026] The radius of curvature at the vertex is: .

[0027] .

[0028] In the formula, and These are the x and y coordinates of the hyperbolic gradient inverted cone structure curve, respectively. For the parameters of the first hyperbola, For the parameters of the second hyperbola, Let be the radius of curvature.

[0029] As a further optimization, the two spiral chip removal grooves and the two cooling outlets are all constructed in a centrally symmetrical distribution. Both cooling outlets are connected to the cooling flow channels to form a Y-shaped cooling hole structure.

[0030] The cooling channels are arranged along the central axis of the drill shank and drill rod, and the cooling inlet is located at the end of the drill shank. The cooling inlet, cooling channels, and cooling outlet are all manufactured by electrical discharge machining.

[0031] As further optimization, the drill shank diameter is 4 mm. The drill rod and drill tip diameters are 1 mm. The drill tip length is 1 mm. The length of the spiral chip flute is 4 mm. The cooling outlet is located on the chip removal surface 1.3 mm from the drill tip. The cooling outlet diameter is 0.4 mm.

[0032] As a further optimization, the drill shank and drill rod are made of cemented carbide. The drill tip is connected to the drill rod and drill shank by welding.

[0033] By adopting the above technical solution, the present invention can achieve the following technical effects:

[0034] The PCD drill bit of the present invention, by designing a multi-stage microchannel with a leaf vein structure at the Y-shaped outlet of the cooling hole, can still guide the coolant to the drill tip processing area and the back of the chisel area when the cooling hole outlet is blocked or closed, so as to cool the drill tip area in all directions and improve the cooling effect. Attached Figure Description

[0035] To more clearly illustrate the technical solutions of the specific embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0036] Figure 1 This is a front view of a PCD drill bit.

[0037] Figure 2 This is a half-section view of a PCD drill bit.

[0038] Figure 3 This is the first isometric view of the PCD drill bit.

[0039] Figure 4 This is the second isometric view of the PCD drill bit.

[0040] Figure 5 This is a top-view cross-sectional view of a PCD drill bit.

[0041] The markings in the diagram are: 1-Drill shank, 2-Drill rod, 3-Drill tip, 4-Helical groove, 5-Chip removal surface, 6-Vein structure microchannel, 7-Helical rifling microchannel, 8-Hyperbolic gradient inverted cone structure, 9-Cooling inlet, 10-Cooling channel, 11-Cooling outlet, 12-First branch microchannel, 13-Main vein microchannel, 14-Second branch microchannel. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0043] Depend on Figures 1 to 5 As shown, this embodiment of the invention provides a PCD drill bit with a Y-shaped internal cooling hole, which includes a drill shank 1, a drill rod 2, and a drill tip 3. The drill tip 3 is made of PCD material and is attached to the drill rod 2.

[0044] The drill tip 3 is constructed as a multi-apex drill tip and has two helical grooves 4 along the first helical direction. The drill rod 2 has two chip removal surfaces 5 that are respectively connected to the two helical grooves 4. The helical grooves 4 and the chip removal surfaces 5 are connected to form a helical chip removal groove.

[0045] The drill shank 1 and drill rod 2 are provided with cooling holes. The cooling holes are Y-shaped and have a cooling inlet 9, a cooling channel 10, and two cooling outlets 11. The two cooling outlets 11 are respectively connected to the two chip removal surfaces 5.

[0046] The spiral chip removal groove is provided with a leaf vein structure microchannel 6 that connects to the cooling outlet 11, so that the coolant can flow to the end of the drill tip 3.

[0047] The cooling channel 10 has spiral rifling microgrooves 7 arranged on its sidewall along the second spiral direction. The first spiral direction is opposite to the second spiral direction, so that when the spiral chip removal groove removes chips, the spiral rifling microgrooves 7 can further supply coolant to the drill tip 3.

[0048] This embodiment of a PCD drill bit with a Y-shaped internal cooling hole includes a drill shank 1, a drill rod 2, and a drill tip 3. The drill shank 1 and drill rod 2 are made of cemented carbide. The drill tip 3 is made of PCD material. The drill tip 3 is welded to the drill rod 2 and drill shank 1. A spiral chip removal groove and a multi-apex drill tip structure are provided near the drill tip 3.

[0049] This embodiment of a PCD drill bit with a Y-shaped internal cooling hole features a Y-shaped cooling hole designed at the center of the drill shank 1 and drill rod 2. The Y-shaped cooling hole includes a cooling inlet 9, a cooling channel 10, and a cooling outlet 11. This embodiment has only one cooling inlet 9, located at the end of the tool holder. During machining, the cooling inlet 9 connects to the spindle center hole, allowing coolant to enter the tool holder's cooling inlet 9 through the spindle center hole.

[0050] Since it is difficult to machine the cooling outlet 11 on the PCD drill tip 3, in this embodiment, the cooling outlet 11 of the cooling hole is designed on the chip removal curved surface 5 where the carbide drill rod 2 connects to the helical groove 4 of the PCD drill tip 3. It can be understood that the chip removal curved surface 5 is also part of the helical chip removal groove, only this part is set on the drill rod 2. The two bifurcated cooling outlets 11 are centrally symmetrically distributed, and the cooling outlets 11 are connected to the cooling flow channel 10 at the center of the drill rod 2 and the drill shank 1, forming a Y-shaped cooling hole structure.

[0051] Understandably, during drilling, the chips generated are discharged upwards along the spiral chip evacuation grooves. However, due to the cutting force, the chips easily adhere to the hole wall, and some chips are even tightly embedded in the hole wall under the cutting force, which can easily block or close the cooling outlet 11, making it difficult for the coolant to reach the machining area of ​​the drill tip 3. At the same time, during drilling, the back of the drill bit is in close contact with the hole wall, making it difficult for the coolant to reach the back of the drill bit to cool the drill bit.

[0052] Based on the above embodiments, in an optional embodiment of the present invention, in order to still be able to deliver coolant to the drilling area at the drill tip 3 when the cooling outlet 11 is blocked or closed, this embodiment designs a multi-stage leaf vein structure microchannel 6 on the spiral chip removal groove to connect the cooling outlet 11.

[0053] like Figure 3 and Figure 4As shown, the leaf vein structure microchannel 6 includes a main vein microchannel 13 arranged along the spiral line of the spiral chip removal groove, and a first branch microchannel 12 and a second branch microchannel 14 extending outward from the main vein microchannel 13. The main vein microchannel 13 starts at the cooling outlet 11, extends along the middle position of the spiral chip removal groove, and terminates in the processing area of ​​the drill tip 3. The branch microchannels extend along the side of the spiral chip removal groove from the main vein microchannel 13 to the backing area next to the spiral chip removal groove. The first branch microchannel 12 and the second branch microchannel 14 are spaced apart along the axial direction of the drill bit. In this embodiment, each spiral chip removal groove is provided with one main vein microchannel 13, two first branch microchannels 12, and two second branch microchannels 14. The two first branch microchannels 12 are located on both sides of the main vein microchannel 13. The two second branch microchannels 14 are located on both sides of the main vein microchannel 13.

[0054] Preferably, the angle between the first branch microchannel 12 and the main vein microchannel 13 is 30 to 60 degrees. The angle between the second branch microchannel 14 and the main vein microchannel 13 is 30 to 60 degrees. The width of the main vein microchannel 13 is 0.04 mm to 0.06 mm. The depth of the main vein microchannel 13 is 0.04 mm to 0.06 mm. The width of the first branch microchannel is 0.01 mm to 0.03 mm. The depth of the first branch microchannel is 0.01 mm to 0.03 mm. The width of the second branch microchannel is 0.01 mm to 0.03 mm. The depth of the second branch microchannel is 0.01 mm to 0.03 mm.

[0055] Specifically, the angle between the first branch microchannel 12 and the main pulse microchannel 13 is 45 degrees. The angle between the second branch microchannel 14 and the main pulse microchannel 13 is 45 degrees. The width and depth of the main pulse microchannel 13 are both 0.05 mm. The width and depth of both the first branch microchannel and the second branch microchannel are both 0.02 mm.

[0056] In this embodiment, the main vein microchannel 13 of the leaf vein structure starts at the cooling outlet 11 and ends at the drilling area of ​​the drill tip 3. The main vein has branching microchannels that extend to the back area of ​​the spiral chip removal groove. Through the design of the leaf vein structure microchannel 6, even when the cooling outlet 11 is blocked or closed, the coolant can still be guided to the drilling area and the back area of ​​the drill tip 3, providing all-around cooling to the drill tip 3 area, thereby improving cooling and chip removal efficiency.

[0057] Based on the above embodiments, in an optional embodiment of the present invention, such as Figure 5 As shown, This refers to the axis of the drill bit. For example...Figure 2 As shown, the cooling inlet 9 of the PCD drill bit is located at the end of the drill shank 1, and the cooling channel 10 is located at the center of the drill shank 1 and the drill rod 2. The cooling channel 10 is connected to the cooling inlet 9. The cross-sectional shape of the cooling channel 10 is cylindrical, and its diameter is... The construction thickness is 0.5mm.

[0058] On the sidewall of the cooling channel 10, spiral rifling microgrooves 7 are designed, spiraling counterclockwise from the drill shank 1 to the drill rod 2 (i.e., the direction of the chip removal grooves is right-handed, and the direction of the rifling is left-handed). Preferably, the number of spiral rifling microgrooves 7 is 4-8, and is an even number. The helix angle of the spiral rifling microgrooves 7 is ≤15°. During high-speed drilling, the coolant is subjected to centrifugal force, causing the coolant to flow counterclockwise downwards along the spiral rifling microgrooves 7, guiding the coolant from the cooling inlet 9 end to the cooling outlet 11 end of the cooling hole, rather than impacting the cooling hole wall in the vertical direction and creating turbulence, thereby increasing the flow velocity of the coolant in the cooling channel 10 and improving the cooling performance of the drill bit. The number of spiral rifling microgrooves 7 is even, and they are arranged rotationally symmetrically. The distance between the negative lines of two opposing spiral rifling microgrooves 7 is... The diameter is 0.55mm. Through the spiral rifling microgrooves 7, the drill bit can generate a propulsive force on the coolant in the cooling channel during operation, causing it to flow further towards the drill tip 3, thus improving the cooling effect and showing significant progress.

[0059] Based on the above embodiments, in an optional embodiment of the present invention, such as Figure 2 As shown, the cooling inlet 9 is constructed as a hyperbolic gradient inverted cone structure 8. The opening of the hyperbolic gradient inverted cone structure 8 is connected to the center hole of the spindle, and the end of the hyperbolic gradient inverted cone structure 8 is connected to the cooling channel 10, thereby increasing the flow rate and velocity of the coolant entering the cooling hole.

[0060] The model of hyperbolic gradient inverted cone structure 8 is as follows: .

[0061] The radius of curvature at the vertex is: .

[0062] In the formula, and These are the x and y coordinates of the hyperbolic gradient inverted cone structure 8, respectively. For the parameters of the first hyperbola, For the parameters of the second hyperbola, Let be the radius of curvature.

[0063] In this embodiment, the cooling inlet 9 is designed as a hyperbolic gradient inverted cone structure 8, which can reduce the abrupt change in cross-section when entering the tool holder cooling hole from the spindle center hole, thereby increasing the flow rate and velocity of the coolant entering the cooling hole. This has outstanding substantial features and significant progress.

[0064] The following example uses a specific drill bit size.

[0065] In a preferred embodiment, a PCD drill bit with a Y-shaped internal cooling hole is designed as follows: The PCD drill bit includes a drill shank 1, a drill rod 2, and a drill tip 3. The drill shank 1 and drill rod 2 are made of cemented carbide. The drill tip 3 is made of PCD material. The drill shank 1 and drill rod 2 are integral structures, and the drill tip 3 is welded to the drill rod 2 and drill shank 1. Preferably, the drill shank 1 has a diameter of 4 mm. The drill rod 2 and drill tip 3 have a diameter of 1 mm. The PCD drill tip 3 has a multi-apex structure and a length of 1 mm. A spiral chip removal groove with a length of 4 mm is provided near the drill tip 3. A chip removal curved surface 5 is provided on the drill rod 2. After the drill tip 3 and drill rod 2 are welded, the spiral chip removal groove and the chip removal curved surface 5 are connected to form a complete spiral groove 4.

[0066] A Y-shaped cooling hole is designed at the center of the drill shank 1 and drill rod 2. The Y-shaped cooling hole includes a cooling inlet 9, a cooling channel 10, and a cooling outlet 11. There are two cooling outlets 11, located in the chip removal curved surface 5 31.3 mm from the drill tip. The diameter of the cooling outlet 11 is 0.4 mm. The two branched cooling outlets 11 are centrally symmetrically distributed. The cooling outlets 11 are connected to the cooling channel 10, forming the Y-shaped cooling hole design.

[0067] A blade-vein structure microchannel 6, connected to the cooling outlet 11, is provided in the spiral chip removal groove. The blade-vein structure microchannel 6 includes a main vein microchannel 13 and multiple levels of branch microchannels. The branch microchannels are arranged around the main vein microchannel 13.

[0068] The main vein microchannel 13 of the leaf vein structure has a width and depth of 0.05 mm, starts at the cooling outlet 11, extends along the middle of the spiral chip removal groove, and ends at the machining area of ​​the drill tip 3.

[0069] In a preferred embodiment, a primary branch microchannel and a secondary branch channel are provided, both symmetrically distributed left and right. The width and depth of the branch microchannels are 0.02 mm, and the branch microchannels form a 45° angle with the main pulse microchannel 13, extending along the side of the spiral chip removal groove to the back areas on both sides of the spiral chip removal groove. This ensures that even when the cooling outlet 11 is blocked or closed, the coolant can still be guided to the machining area of ​​the drill tip 3 and the back area, providing all-round cooling to the drill tip 3 area, thereby improving the cooling effect.

[0070] The cooling channel 10 is located at the center of the drill shank 1 and the drill rod 2, and is connected to the cooling inlet 9. The cross-sectional shape of the cooling channel 10 is a cylinder with a diameter of 0.5 mm. The cooling inlet 9 and the cooling channel 10 on the drill shank 1, as well as the cooling outlet 11 on the drill rod 2, are all manufactured by electrical discharge machining. Then, the drill shank 1, the drill rod 2, and the drill tip 3 are welded together to form a PCD drill bit with a Y-shaped internal cooling hole.

[0071] Counterclockwise helical rifling microgrooves 7 are designed on the wall of the cooling channel 10. During drilling, centrifugal force causes the coolant to flow downwards along the helical rifling microgrooves 7, increasing the flow rate of the coolant in the cooling holes. The shape of the helical rifling microgrooves 7 in cross-section is as follows: Figure 5 As shown. The cross-sectional profile of the helical rifling microgroove 7 is approximately rectangular. The raised portion of the helical groove 4 is called the male groove, and its width is... The recessed groove is called a negative line, and its width is... In this embodiment, the width of the negative line is greater than the width of the positive line. This is to improve the effect of the spiral rifling microgrooves 7 on increasing the flow rate of the coolant.

[0072] The difference in radius between the bullish and bearish candlesticks is called the rifling depth, and its depth is... Use rounded corners to connect the bearish and bullish candlesticks, with a radius of [missing information]. To reduce stress concentration at the root of the rifling and reduce turbulence, in a preferred embodiment, the spiral rifling microgroove 7 is a uniform rifling, the number of spiral rifling microgrooves 7 is 4, the helix angle of the rifling is a fixed value of 10°, and the width and depth of the spiral rifling microgroove 7 are 0.05 mm.

[0073] The cooling inlet 9 is located at the end of the tool holder and is designed as a hyperbolic gradient inverted cone structure 8. The opening is used to connect with the center hole of the spindle, and the end of the hyperbolic gradient inverted cone structure 8 is used to connect with the cooling channel 10, thereby increasing the flow rate and velocity of the coolant entering the cooling hole.

[0074] The model of hyperbolic gradient inverted cone structure 8 is as follows: .

[0075] The radius of curvature at the vertex is: .

[0076] In this embodiment, the radius of curvature It is equal to the radius of the cooling channel 10, which is 0.5mm. Preferred, .

[0077] Obviously, the above detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to describe preferred embodiments, not all embodiments, and is not intended to limit the invention. Various modifications and variations can be made to the invention by those skilled in the art. Based on the embodiments of the invention, any modifications, equivalent substitutions, improvements, etc., made by those skilled in the art to all other embodiments obtained without inventive effort are within the scope of protection of the invention.

Claims

1. A PCD drill bit with a Y-shaped internal cooling hole, characterized in that, It includes a drill shank (1), a drill rod (2) and a drill tip (3); the drill tip (3) is made of PCD material and is attached to the drill rod (2); The drill tip (3) is constructed as a multi-apex drill tip structure and has two spiral grooves (4) arranged along the first spiral direction; the drill rod (2) is provided with two chip removal surfaces (5) respectively connected to the two spiral grooves (4); the spiral grooves (4) and the chip removal surfaces (5) are connected to form the spiral chip removal groove of the drill bit; The drill shank (1) and drill rod (2) are provided with cooling holes; the cooling holes are constructed in a Y-shape and are provided with a cooling inlet (9), a cooling channel (10) and two cooling outlets (11); the two cooling outlets (11) are respectively connected to the two chip removal surfaces (5). The spiral chip removal groove is provided with a leaf vein structure microchannel (6) that connects to the cooling outlet (11) so that the coolant can flow to the end of the drill tip (3). The cooling channel (10) has a spiral rifling microgroove (7) on its sidewall along the second spiral direction; the first spiral direction is opposite to the second spiral direction, so that when the spiral chip removal groove removes chips, the spiral rifling microgroove (7) can further supply coolant to the drill tip (3); The leaf vein structure microchannel (6) includes a main vein microchannel (13) arranged along the spiral line of the spiral chip removal groove, and a first branch microchannel (12) extending outward from the main vein microchannel (13); the main vein microchannel (13) starts at the cooling outlet (11), extends along the middle position of the spiral chip removal groove, and terminates at the processing area of ​​the drill tip (3); the first branch microchannel (12) extends along the side of the spiral chip removal groove from the main vein microchannel (13) to the back of the shovel next to the spiral chip removal groove. The cooling inlet (9) is constructed as a hyperbolic tapered inverted cone structure (8). The opening of the hyperbolic tapered inverted cone structure (8) is used to connect with the center hole of the spindle, and the end of the hyperbolic tapered inverted cone structure (8) is used to connect with the cooling channel (10), thereby increasing the flow rate and velocity of the coolant entering the cooling hole. The model of the hyperbolic gradient inverted cone structure (8) is as follows: ; The radius of curvature at the vertex is: ; ; In the formula, and These are the x and y coordinates of the hyperbola gradually changing inverted cone structure (8) curve, respectively. For the parameters of the first hyperbola, For the parameters of the second hyperbola, Let be the radius of curvature.

2. A PCD drill bit with a Y-shaped internal cooling hole according to claim 1, characterized in that, The leaf vein structure microchannel (6) also includes a second branch microchannel (14) extending outward from the main vein microchannel (13); the second branch microchannel (14) extends along the side of the spiral chip removal groove from the main vein microchannel (13) to the back area of ​​the shovel next to the spiral chip removal groove. The first branch microchannel (12) and the second branch microchannel (14) are spaced apart along the axial direction of the drill bit; Each spiral chip removal groove is provided with one main pulse microchannel (13), two first branch microchannels (12), and two second branch microchannels (14); the two first branch microchannels (12) are respectively located on both sides of the main pulse microchannel (13); the two second branch microchannels (14) are respectively located on both sides of the main pulse microchannel (13); The angle between the first branch microchannel (12) and the main vein microchannel (13) is 30 to 60 degrees; The angle between the second branch microchannel (14) and the main vein microchannel (13) is 30 to 60 degrees; The width of the main vein microchannel (13) is 0.04 mm to 0.06 mm; The depth of the main vein microchannel (13) is 0.04 mm to 0.06 mm; The width of the first branch microchannel is 0.01 mm to 0.03 mm; The depth of the first branch microchannel is 0.01 mm to 0.03 mm; The width of the second branch microchannel is 0.01 mm to 0.03 mm; The depth of the second branch microchannel is 0.01 mm to 0.03 mm.

3. A PCD drill bit with a Y-shaped internal cooling hole according to claim 2, characterized in that, The angle between the first branch microchannel (12) and the main vein microchannel (13) is 45 degrees; The angle between the second branch microchannel (14) and the main pulse microchannel (13) is 45 degrees; The width and depth of the main vein microchannel (13) are both 0.05 mm; The width and depth of both the first branch microchannel and the second branch microchannel are 0.02 mm.

4. A PCD drill bit with a Y-shaped internal cooling hole according to claim 1, characterized in that, The number of helical rifling microgrooves (7) is 4, 6 or 8, and they are arranged in a rotationally symmetrical manner; the helix angle of the helical rifling microgrooves (7) is ≤15°; The cross-sectional profile of the helical rifling microgroove (7) is rectangular; wherein, the raised part of the helical rifling microgroove (7) is called the male groove, and its width is The grooves (7) of the spiral rifling are recessed and called indentations, with a width of [missing information]. The width of the bearish candlestick is greater than the width of the bullish candlestick. ; The difference in radius between the bearish and bullish lines is called the rifling depth, and its depth is... Use rounded corners to connect the bearish and bullish candlesticks, with a radius of [missing information]. .

5. A PCD drill bit with a Y-shaped internal cooling hole according to claim 4, characterized in that, The number of microgrooves (7) in the helical rifling is 4; the helix angle of the rifling is a fixed value of 10°; Diameter of cooling channel (10) The construction is 0.5mm, and the width and depth of the spiral rifling microgrooves (7) are both 0.025mm, so that the distance between the negative lines of the two opposing spiral rifling microgrooves (7) is... It is 0.55mm; The spiral chip removal grooves rotate clockwise from the drill rod (2) to the drill tip (3); the spiral rifling microgrooves (7) rotate counterclockwise from the drill shank (1) to the drill rod (2).

6. A PCD drill bit with a Y-shaped internal cooling hole according to any one of claims 1 to 5, characterized in that, The two spiral chip removal grooves and the two cooling outlets (11) are all constructed to be centrally symmetrically distributed; the two cooling outlets (11) are connected to the cooling channel (10) to form a Y-shaped cooling hole; The cooling channel (10) is arranged along the central axis of the drill shank (1) and the drill rod (2), and the cooling inlet (9) is located at the end of the drill shank (1); the cooling inlet (9), the cooling channel (10), and the cooling outlet (11) are all made by electrical discharge machining.

7. A PCD drill bit with a Y-shaped internal cooling hole according to any one of claims 1 to 5, characterized in that, The drill shank (1) has a diameter of 4 mm; the drill rod (2) and drill tip (3) have a diameter of 1 mm; the drill tip (3) has a length of 1 mm; The length of the spiral chip removal groove is 4 mm; the cooling outlet (11) is located on the chip removal surface (5) 1.3 mm away from the drill tip (3); the diameter of the cooling outlet (11) is 0.4 mm.

8. A PCD drill bit with a Y-shaped internal cooling hole according to any one of claims 1 to 5, characterized in that, The drill shank (1) and drill rod (2) are made of cemented carbide; the drill tip (3) is connected to the drill rod (2) and drill shank (1) by welding.

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