Deep hole drilling tool for high-strength die steel and drilling process thereof

Abstract

The application relates to the technical field of deep hole machining, in particular to a deep hole drilling tool for high-strength die steel and a drilling process thereof. The deep hole drilling tool for high-strength die steel comprises a drilling tool body, a liquid inlet channel and a backflow channel are arranged on the drilling tool body, an annular slit is defined between the drilling tool body and a hole, and a throttle ring is coaxially arranged on the drilling tool body. In the machining process, the deep hole drilling tool for high-strength die steel synchronously delivers cutting fluid into the liquid inlet channel and the annular slit, the liquid inlet channel supplies the required cutting fluid for cutting, the inner chip removal and heat exchange and cooling of the deep hole machining are stably completed, the drilling tool body is supported by the cutting fluid entering the annular slit, and the pressure drop in the annular slit is greatly reduced under the action of the throttle ring, the support stability is improved, the problems such as hole mouth deformation and hole wall scratch are avoided, and the like.

Description

Technical Field

[0001] This invention relates to the field of deep hole machining technology, specifically to a high-strength mold steel deep hole drill and its drilling process. Background Technology

[0002] High-strength mold steel, as a high-performance steel designed specifically for mold manufacturing, has the core characteristics of extremely high strength, hardness, wear resistance and fatigue resistance. It can maintain stable dimensional accuracy and surface quality under extreme working conditions, thereby significantly extending the service life of molds and reducing production costs. It is now widely used in intelligent manufacturing, precision machinery, high-end equipment and other fields.

[0003] Currently, the main mature deep hole machining tools in the industry include gun drills, BTA drills (Boring and Trepanning Assoeiation), jet-suction drills, and DF drills (Double Feeder). Based on the chip removal method, they can be divided into two main categories: external chip removal and internal chip removal. Gun drills belong to the category of external chip removal deep hole machining tools; while BTA drills, jet-suction drills, and DF drills, although having different machining system structures, all belong to the category of internal chip removal deep hole machining tools and are the mainstream tool types for high-strength mold steel deep hole finishing.

[0004] In traditional BTA drilling tools, cutting fluid enters through the lubricator during machining, flowing along the gap between the inner wall of the deep hole and the drill pipe to the cutting position of the drill bit. It then flows through the gaps in the guide bars, lubricating them. The fluid, carrying chips cut by the cutting edge and heat generated during cutting, flows out through the hollow channels of the drill pipe, forming hydrostatic support based on a high-pressure oil film. This provides excellent heavy-duty performance. However, as the drilling depth increases, the frictional resistance along the outer annular slit continuously increases, and the oil pressure decreases significantly along the flow path. If the loss is compensated by increasing the inlet pressure, it will result in an excessively large axial pressure difference in the slit, leading to an excessively thick oil film in shallow holes and an insufficient oil film in deep holes. This causes drill pipe support imbalance, easy vibration and deviation, and defects such as borehole deformation and borehole wall scratches. Summary of the Invention

[0005] This invention provides a deep hole drill bit made of high-strength mold steel and its drilling process to solve the problem that the friction resistance along the outer annular slit of existing drill bits continuously increases with the increase of drilling depth, and the oil pressure decreases significantly along the drilling process.

[0006] The present invention discloses a deep hole drill for high-strength mold steel and its drilling process, which adopts the following technical solution: A deep hole drill for high-strength mold steel is used for drilling high-strength mold steel, comprising a drill body, one end of which is provided with a cutting edge, and a fluid inlet channel and a return channel are provided on the drill body. The fluid inlet channel is eccentrically arranged relative to the drill body, and the return channel is coaxially arranged with the drill body. The area between the cutting edge and the drill hole is called the cutting area, and the fluid inlet channel is connected to the return channel through the cutting area. An annular slit is defined between the outer peripheral wall of the drill body and the inner peripheral wall of the drill hole, and a throttling ring is coaxially arranged on the drill body. The two ends of the fluid inlet channel along the axial direction of the drill body are respectively called the first end and the second end, and the throttling ring is located between the first end and the second end. The gap between the throttling ring and the inner peripheral wall of the drill hole is smaller than the gap between the outer peripheral wall of the drill body and the inner peripheral wall of the drill hole.

[0007] Furthermore, the drill body includes a drill bit and a drill rod. The drill bit is located at one end of the drill rod and is coaxial with the drill rod. The cutting edge is located at the end of the drill bit away from the drill rod. A throttling ring is detachably installed on the drill bit. A first branch is opened on the drill rod, which is eccentrically positioned relative to the drill rod. A second branch is opened on the drill bit, which is eccentrically positioned relative to the drill bit and communicates with the first branch. The fluid inlet channel is defined by the first branch and the second branch. A return port is opened on the drill bit and extends through its axial direction. The return port communicates with the cutting area. The return channel is opened on the drill rod and is coaxial with the drill rod. The fluid inlet channel communicates with the return channel through the return port.

[0008] Furthermore, multiple guide blocks are spaced apart on the outer peripheral wall of the drill bit. The guide blocks are arranged along the axial direction of the drill bit and can contact the inner peripheral wall of the borehole.

[0009] Furthermore, one end of the throttle ring is provided with multiple connecting blocks, which are evenly distributed around the circumference of the throttle ring, and the connecting blocks are locked to the drill bit by bolts.

[0010] Furthermore, multiple Tesla valves are evenly distributed on the inner peripheral wall of the throttling ring, and these Tesla valves are installed in reverse on the inner peripheral wall of the throttling ring.

[0011] Furthermore, an adjusting ring is screwed onto the drill bit, and in the radial direction of the drill bit, the Tesla valve is located between the throttle ring and the adjusting ring and abuts against the outer peripheral wall of the adjusting ring.

[0012] Furthermore, a deep hole drill for high-strength mold steel also includes an orifice oil feeder. The orifice oil feeder is coaxially arranged with the drill rod and sleeved on the drill rod, and the orifice oil feeder abuts against the end face of the high-strength mold steel. A sealing ring is provided between the two. The orifice oil feeder can deliver cutting fluid to the annular slit and the fluid inlet channel respectively.

[0013] Furthermore, the orifice oil supply device includes a housing and multiple connecting rods. The housing has an inlet with a high-pressure valve. The multiple connecting rods are evenly distributed around the central axis of the housing, and an annular chamber is defined between the housing and the multiple connecting rods. Multiple one-way components are evenly distributed along the axial direction of the drill rod. The one-way components include multiple one-way valves. The multiple one-way valves are evenly distributed in the circumferential direction of the drill rod. The one-way valves open only when the drill rod is in the housing and allow the cutting fluid to enter the first branch.

[0014] Furthermore, the drill pipe has multiple mounting holes that communicate with the first branch. Each mounting hole corresponds to a one-way valve. The one-way valve includes a ball valve body and a protrusion. Both the ball valve body and the protrusion are arranged along the radial direction of the drill pipe and are fixedly connected. The ball valve body is installed in the corresponding mounting hole through a first elastic element. Part of the ball valve body is located in the first branch, while part of the ball valve body and the protrusion extend out of the mounting hole. The protrusion can abut against the connecting rod. The surface area of ​​the part of the ball valve body located in the first branch is greater than the surface area of ​​the part of the ball valve body extending out of the mounting hole.

[0015] This invention also provides a drilling process for a deep hole drill made of high-strength mold steel, which includes the following steps: S10: Align the drill body with the high-strength mold steel hole to be machined, and feed and cut through the cutting edge.

[0016] S20 synchronously delivers cutting fluid into the inlet channel and the annular slit.

[0017] S30, the cutting fluid entering the inlet channel is transported to the cutting area and returned through the return channel to cool the cutting environment and remove the chips generated during cutting; the cutting fluid entering the annular slit flows along the annular slit to the throttling ring to provide support for the drill body.

[0018] The beneficial effects of the present invention are as follows: During the processing of a high-strength mold steel deep hole drill bit, the present invention forms an independent and cooperative cooling and chip removal channel and a pressure stabilizing support channel by simultaneously delivering cutting fluid to the fluid inlet channel and the annular slit. One stream of cutting fluid is fed into the inlet channel, which transports the fluid to the cutting area, providing real-time cooling and lubrication to the cutting edge. Simultaneously, it carries away the chips and high-temperature heat generated during cutting, rapidly returning to the source via a return channel connected to the inlet channel. This inlet channel supplies the necessary cutting fluid for stable chip removal and heat exchange during deep hole machining, ensuring a low-temperature, clean machining environment in the cutting area. The other stream of cutting fluid flows into the annular slit, providing support for the drill bit body. When the cutting fluid reaches the throttling ring, it is blocked, reducing its flow rate and the amount of fluid exiting the annular slit. This significantly reduces the pressure drop within the annular slit, making the pressure difference more uniform in deeper holes, improving support stability, preventing vibration and deviation, and avoiding problems such as borehole deformation and borehole wall scratches.

[0019] Furthermore, by installing a Tesla valve on the throttling ring, the flow rate of cutting fluid passing between the throttling ring and the inner circumferential wall of the borehole can be kept as constant as possible throughout the drilling process. This can improve the flow rate variation caused by slight pressure drop to a certain extent, making the flow rate of cutting fluid entering the cutting area more stable and cleaning the chips more effectively. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is an installation state diagram of the drill body, which is an embodiment of a high-strength mold steel deep hole drill of the present invention. Figure 2 This is a structural diagram of the drill body and the high-strength mold steel, representing an embodiment of a deep hole drill made of high-strength mold steel according to the present invention. Figure 3 for Figure 2 A cross-sectional view of the structure shown; Figure 4 for Figure 3 Enlarged view of point A in the middle; Figure 5 for Figure 4 Enlarged view of point C in the middle; Figure 6 for Figure 3Enlarged view of point B in the middle; Figure 7 for Figure 6 Enlarged view of point D in the middle; Figure 8 This is a cross-sectional view of a drill bit according to an embodiment of a high-strength mold steel deep hole drill bit of the present invention; Figure 9 This is a schematic diagram of the adjusting ring of an embodiment of a high-strength mold steel deep hole drill bit according to the present invention; Figure 10 This is a schematic diagram of a throttling ring in an embodiment of a high-strength mold steel deep hole drill bit according to the present invention; Figure 11 This is a cross-sectional view of the orifice oil feeder of an embodiment of a high-strength mold steel deep hole drill of the present invention.

[0022] In the diagram: 100, high-strength mold steel; 200, drill body; 201, cutting edge; 202, fluid inlet channel; 203, return channel; 204, annular slit; 210, drill bit; 211, guide block; 212, second branch; 213, return port; 220, drill rod; 221, first branch; 230, throttling ring; 231, connecting block; 232, Tesla valve; 240, adjusting ring; 250, orifice oil feeder; 251, outer shell; 252, connecting rod; 253, high-pressure valve nozzle; 260, one-way valve; 261, ball valve body; 262, protrusion; 263, first elastic element; 300, frame; 310, workpiece clamping end; 320, drill mounting end. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] An embodiment of a high-strength mold steel deep hole drill bit of the present invention, such as... Figures 1 to 11 As shown.

[0025] A deep hole drill for high-strength mold steel is used to drill holes in high-strength mold steel 100. It includes a drill body 200, one end of which is provided with a cutting edge 201. The drill body 200 is provided with a fluid inlet channel 202 and a return channel 203. The fluid inlet channel 202 is eccentrically arranged relative to the drill body 200, and the return channel 203 is coaxially arranged with the drill body 200. The area between the cutting edge 201 and the drill hole is called the cutting area. The fluid inlet channel 202 is connected to the return channel 203 through the cutting area.

[0026] An annular slit 204 is defined between the outer peripheral wall of the drill bit body 200 and the inner peripheral wall of the borehole. A throttling ring 230 is coaxially mounted on the drill bit body 200. The two ends of the fluid inlet channel 202 along the axial direction of the drill bit body 200 are referred to as the first end and the second end, respectively. The throttling ring 230 is located between the first end and the second end, and does not restrict the cutting fluid in the fluid inlet channel 202 from entering the cutting area. The gap between the throttling ring 230 and the inner peripheral wall of the borehole is smaller than the gap between the outer peripheral wall of the drill bit body 200 and the inner peripheral wall of the borehole. Specifically, it can be considered that the throttling ring 230 is close to being in close contact with the inner peripheral wall of the borehole, but still leaves a certain gap, allowing only a small amount of cutting fluid to pass through.

[0027] Similar to existing technologies, a deep hole drill for high-strength mold steel also includes a frame 300, a workpiece clamping end 310, and a drill mounting end 320. The workpiece clamping end 310 and the drill mounting end 320 are both mounted on the frame 300. The drill body 200 is mounted on the drill mounting end 320, and the high-strength mold steel 100 to be processed is mounted on the workpiece clamping end 310.

[0028] During deep hole machining, the assembled drill body 200 is aligned with the hole to be machined in the high-strength mold steel 100 and fed for cutting. The drilling and cutting operation of the high-strength mold steel 100 is completed through the cutting edge 201 at the end of the drill body 200.

[0029] During the machining process, cutting fluid is simultaneously supplied to the inlet channel 202 and the annular slit 204, forming independent and collaborative cooling and chip removal channels and pressure-stabilizing support channels. One path of cutting fluid is sent into the inlet channel 202, and the cutting fluid is transported to the cutting area along the inlet channel 202 to cool and lubricate the cutting edge 201 in real time. At the same time, it carries away the chips and high-temperature heat generated during the cutting process, and is quickly discharged through the return channel 203 connected to the inlet channel 202. The cutting fluid required for cutting is supplied by the inlet channel 202, and the internal chip removal and heat exchange cooling of deep hole machining are stably completed, ensuring a low-temperature and clean machining environment in the cutting area. The other path of cutting fluid is introduced into the annular slit 204, and the cutting fluid flows along the annular slit 204 to form a high-pressure oil film, which provides support for the drill body 200. When the cutting fluid flows to the throttling ring 230, it is throttled. The throttling ring 230 reduces the flow rate of the cutting fluid, thereby decreasing the flow rate of the cutting fluid exiting through the annular slit 204. This significantly reduces the pressure drop within the annular slit 204. In other words, although the gap between the throttling ring 230 and the inner circumferential wall of the borehole is small, a small amount of cutting fluid still passes between the throttling ring 230 and the inner circumferential wall of the borehole due to the persistent gap. As the borehole depth increases, the oil pressure will still decrease to some extent along the drilling path. However, compared to traditional BTA drill bits, the degree of oil pressure decrease along the drilling path is significantly reduced, making the pressure difference between different parts of the borehole tend to be uniform when the borehole is deep. This improves support stability, prevents chatter and deviation, and avoids problems such as borehole deformation and borehole wall scratches.

[0030] In a further embodiment, the drill body 200 includes a drill bit 210 and a drill rod 220. The drill bit 210 is disposed at one end of the drill rod 220 and is coaxial with the drill rod 220. Specifically, the drill bit 210 is screwed to the drill rod 220, and a sealing ring is provided between the drill bit 210 and the drill rod 220. The diameters of both the drill rod 220 and the drill bit 210 are smaller than the diameter of the deep hole to be machined.

[0031] The cutting edge 201 is located at the end of the drill bit 210 away from the drill rod 220. Multiple guide blocks 211 are spaced apart on the outer peripheral wall of the drill bit 210. The guide blocks 211 are arranged along the axial direction of the drill bit 210 and can contact the inner peripheral wall of the borehole to support the inner wall of the borehole. A throttling ring 230 is detachably mounted on the drill bit 210. A first branch 221 is provided on the drill rod 220, eccentrically positioned relative to the drill rod 220. A second branch 212 is provided on the drill bit 210, eccentrically positioned relative to the drill bit 210 and communicating with the first branch 221. The fluid inlet channel 202 is defined by the first branch 221 and the second branch 212. The drill bit 210 has a return port 213 that extends through it along its axial direction. The return port 213 is connected to the cutting area. The return channel 203 is opened on the drill rod 220 and is coaxial with the drill rod 220. The fluid inlet channel 202 is connected to the return channel 203 through the return port 213.

[0032] The throttle ring 230 has multiple connecting blocks 231 at one end. The multiple connecting blocks 231 are evenly distributed around the circumference of the throttle ring 230. The connecting blocks 231 are locked to the drill bit 210 by bolts, so that the throttle ring 230 can be detachably installed on the drill bit 210.

[0033] By setting up the drill bit 210 and drill rod 220, when the cutting fluid is fed into the first branch 221 on the drill rod 220, it will be sent from the first branch 221 to the cutting area through the second branch 212 to cool and lubricate the cutting edge 201 in real time. At the same time, it will carry the chips and high-temperature heat generated by the cutting process and quickly return and discharge them through the return port 213 via the return channel 203 connected to the fluid inlet channel 202.

[0034] In a further embodiment, a plurality of Tesla valves 232 are evenly distributed on the inner peripheral wall of the throttling ring 230, and the plurality of Tesla valves 232 are installed in opposite directions on the inner peripheral wall of the throttling ring 230.

[0035] As is commonly known, the Tesla valve 232 is a one-way fluid valve without moving parts. Its core feature lies in achieving a one-way flow effect of low resistance in the forward direction and high resistance in the reverse direction through a fixed geometric structure. When the Tesla valve 232 is installed in the forward direction, the fluid enters in the preset forward direction, and the channel structure guides its smooth diversion and merging, resulting in low pressure drop and stable flow velocity. When the Tesla valve 232 is installed in the reverse direction, the fluid is forced to divert and undergoes violent deflection and backflow. The branched fluids collide, mix, and form vortices at the merging point, resulting in high flow resistance.

[0036] During the drilling process, the oil pressure at the fluid supply point is called P1, which remains constant. The end of the Tesla valve 232 closest to the annular slit 204 is called the front end, and the end of the Tesla valve 232 furthest from the annular slit 204 is called the rear end.

[0037] When the drilling depth is shallow, the oil pressure at the front end of Tesla valve 232 is P2, and the oil pressure at the rear end is P3 (connected to return channel 203, close to atmospheric pressure). When the drilling depth is deep, the oil pressure at the front end of Tesla valve 232 is P4, and the oil pressure at the rear end is still P3. Although the gap between the throttling ring 230 and the inner circumferential wall of the borehole is small, a small amount of cutting fluid still passes through this gap. This results in a certain degree of pressure attenuation along the drilling path as the drilling depth increases, i.e., P2 > P4. Furthermore, the pressure difference between the front and rear ends of the Tesla valve 232 is greater when the drilling depth is shallower than it is when the drilling depth is deeper; that is, P2-P3 > P4-P3. Consequently, the flow rate of cutting fluid passing through the gap between the throttling ring 230 and the inner circumferential wall of the borehole is greater when the drilling depth is shallower than it is when the drilling depth is deeper. This leads to a difference in the overall flow rate entering the cutting zone as the drilling depth increases, ultimately affecting the chip removal effect and resulting in incomplete chip removal.

[0038] In order to balance the flow rate of cutting fluid passing between the throttling ring 230 and the inner peripheral wall of the borehole, this embodiment sets up a Tesla valve 232 and allows the cutting fluid entering the annular slit 204 to flow in reverse within the Tesla valve 232. According to the principle of the Tesla valve 232, the greater the pressure difference between the inlet and outlet, the greater the resistance and the smaller the flow rate.

[0039] When the drilling depth is shallow, the oil pressure P2 (inlet) at the front end of Tesla valve 232 will be much greater than the oil pressure P3 (outlet) at the rear end of Tesla valve 232. This reduces the flow rate of cutting fluid between the throttle ring 230 and the inner circumferential wall of the borehole. When the drilling depth is deep, the pressure difference between the oil pressure P4 (inlet) at the front end of Tesla valve 232 and the oil pressure P3 (outlet) at the rear end of Tesla valve 232 will be smaller than when the drilling depth is shallow, thus reducing the flow rate of cutting fluid between the throttle ring 230 and the inner circumferential wall of the borehole. The flow rate of cutting fluid passing between the inner peripheral walls of the hole can be relatively increased, so that the flow rate of cutting fluid passing through Tesla valve 232 in shallow and deep holes tends to be balanced. Ultimately, the flow rate of cutting fluid passing between throttling ring 230 and the inner peripheral wall of the hole can be kept as constant as possible throughout the drilling process. This can improve the flow rate variation caused by slight pressure drop to a certain extent, make the flow rate of cutting fluid entering the cutting area more stable, and make the chip cleaning effect of cutting fluid more consistent during the drilling process.

[0040] Alternatively, in another possible embodiment, an adjusting ring 240 is screwed onto the drill bit 210, and in the radial direction of the drill bit 210, the Tesla valve 232 is located between the throttle ring 230 and the adjusting ring 240 and abuts against the outer peripheral wall of the adjusting ring 240.

[0041] In this embodiment, by setting an adjusting ring 240 and screwing the adjusting ring 240 to the drill bit 210, during installation, the throttle ring 230 is first put on the drill bit 210 and locked with bolts. Then, the adjusting ring 240 is inserted between the throttle ring 230 and the drill bit 210. Finally, the drill rod 220 is installed to fix it to the drill bit 210.

[0042] During use, the adjusting ring 240 can be rotated according to the required drilling depth to change its position on the drill bit 210, thereby changing the relative position between the adjusting ring 240 and the throttling ring 230, that is, the relative position between the adjusting ring 240 and the Tesla valve 232, thus changing the effective flow path of the cutting fluid within the Tesla valve 232. According to the principle of the Tesla valve 232, when the total channel length of the Tesla valve 232 is shortened, due to the dependence of reverse resistance on the superposition of multiple eddies, the shorter the flow path, the less sufficient the eddy formation and energy dissipation, resulting in increased reverse leakage and weakened unidirectionality. Therefore, when the cutting fluid enters the Tesla valve 232 from the annular slit 204 and flows in the reverse direction, the shorter the flow path of the cutting fluid within the Tesla valve 232, the greater the flow rate, allowing for optimal adjustment within different drilling depth ranges.

[0043] Specifically, during deep hole machining, the process can be divided into segments based on the machining depth. In the axial direction of the borehole, the shallower segment is called the first segment, and the deeper segment is called the second segment. In the first segment, rotating the adjusting ring 240 changes the length of the overlapping portion between the adjusting ring 240 and the Tesla valve 232, making the effective flow path of the Tesla valve 232 L1. After the first segment is completed, the drill body 200 is withdrawn entirely from the borehole, and the adjusting ring 240 is rotated to make the effective flow path of the Tesla valve 232 L2, where L1 > L2. Machining continues in the second segment, resulting in a lower flow rate of cutting fluid through the Tesla valve 232 during drilling in the first segment compared to the flow rate during drilling in the second segment. This segmented adjustment further regulates the flow rate of cutting fluid passing through the throttling ring 230 and the inner circumferential wall of the borehole, making the flow rate of cutting fluid entering the cutting area more stable.

[0044] In a further embodiment, a deep hole drill bit made of high-strength mold steel also includes a borehole oil feeder 250. The borehole oil feeder 250 is mounted on the frame 300, coaxially arranged with the drill rod 220 and sleeved on the drill rod 220, and the borehole oil feeder 250 abuts against the end face of the high-strength mold steel 100, with a sealing ring provided between them. The borehole oil feeder 250 can deliver cutting fluid to the annular slit 204 and the fluid inlet channel 202 respectively.

[0045] The orifice oil supply device 250 includes a housing 251 and multiple connecting rods 252. The housing 251 is cylindrical and hollow, with an inlet and a high-pressure valve 253 connected to an external oil pump. The multiple connecting rods 252 are evenly distributed around the central axis of the housing 251 and are sleeved on the drill rod 220. An annular chamber is defined between the housing 251 and the multiple connecting rods 252. A portion of the cutting fluid entering from the high-pressure valve 253 can enter the space between the drill rod 220 and the connecting rods 252 from the annular chamber, ultimately entering the annular slit 204. Multiple one-way components are evenly distributed along the axial direction of the drill rod 220. Each one-way component includes multiple one-way valves 260, which are evenly distributed in the circumferential direction of the drill rod 220. The one-way valves 260 open only when the drill rod 220 is at the housing 251, allowing the cutting fluid to enter the first branch 221.

[0046] Furthermore, the drill pipe 220 has multiple mounting holes that communicate with the first branch 221. Each mounting hole corresponds to a one-way valve 260. The one-way valve 260 includes a spherical valve body 261 and a protrusion 262. Both the spherical valve body 261 and the protrusion 262 are arranged radially along the drill pipe 220 and fixedly connected. Specifically, the spherical valve body 261 and the protrusion 262 are integrally formed. The spherical valve body 261 is installed in the corresponding mounting hole via a first elastic element 263. Part of the spherical valve body 261 is located within the first branch 221, while parts of the spherical valve body 261 and the protrusion 262 extend beyond the mounting hole. The protrusion 262 can abut against the connecting rod 252. The surface area of ​​the part of the spherical valve body 261 located within the first branch 221 is greater than the surface area of ​​the part of the spherical valve body 261 and the protrusion 262 extending beyond the mounting hole. The first elastic element 263 is arranged along the radial direction of the drill rod 220, and the first elastic element 263 is a compression spring.

[0047] In this embodiment, by setting a one-way valve 260, during use, the cutting fluid is delivered to the annular chamber through the high-pressure valve nozzle 253. A portion of the cutting fluid will enter the space between the drill rod 220 and the connecting rod 252 from the annular chamber, and finally enter the annular slit 204. Another portion of the cutting fluid can enter the first branch 221 through the one-way valve 260. Specifically, taking one of the one-way valves 260 as an example, when the drill rod 220 rotates and moves to the outer casing 251, the protrusion 262 on the one-way valve 260 abuts against the connecting rod 252, thereby opening the one-way valve 260 under the squeezing action of the connecting rod 252, allowing the cutting fluid to enter the first branch 221 through the mounting hole, thus achieving fluid supply. As the drill rod 220 continues to rotate and move away from the housing 251 and into the borehole, the part of the spherical valve body 261 and the protrusion 262 located outside the mounting hole come into the annular slit 204. For ease of explanation, the surface area of ​​the part of the spherical valve body 261 and the protrusion 262 located outside the mounting hole is referred to as S1, and the liquid pressure inside the annular slit 204 is referred to as P5.

[0048] The portion of the spherical valve body 261 located within the mounting hole is situated within the first branch 221. The surface area of ​​this portion of the spherical valve body 261 within the mounting hole is denoted as S2, and the liquid pressure within the first branch 221 is denoted as P6. The throttling ring 230 ensures that the liquid pressure within the annular slit 204 is almost unaffected. However, due to viscous resistance, the liquid pressure P6 within the first branch 221 will be less than the liquid pressure P5 within the annular slit 204. That is, P5 > P6, according to the formula... To prevent the one-way valve 260 from opening when it is in the first branch 221, the pressure F1 in the annular slit 204 needs to be equal to the pressure F2 in the first branch 221, that is, F1=F2. Therefore, in this embodiment, the surface area (S2) of the part of the spherical valve body 261 in the first branch 221 is set to be greater than the surface area (S1) of the part of the spherical valve body 261 and the protrusion 262 extending out of the mounting hole, and the elastic force of the first elastic element 263 is called F3, so that F1=F2+F3. This ensures that when the one-way valve 260 comes into the first branch 221, the one-way valve 260 is in the closed state, preventing the liquid in the annular slit 204 from flowing into the first branch 221.

[0049] By setting the orifice oil feeder 250, cutting fluid can be delivered to the annular slit 204 and the fluid inlet channel 202 respectively, and only one oil pump is needed, reducing costs.

[0050] Alternatively, two oil pumps can be used to deliver cutting fluid to the annular slit 204 and the fluid inlet channel 202 respectively.

[0051] This invention also provides a drilling process for a deep hole drill made of high-strength mold steel, which includes the following steps: S10, align the drill body 200 with the hole to be machined in the high-strength mold steel 100, and perform feed cutting through the cutting edge 201.

[0052] S20, cutting fluid is simultaneously delivered into the fluid inlet channel 202 and the annular slit 204.

[0053] S30, the cutting fluid entering the inlet channel 202 is transported to the cutting area and returned through the return channel 203 to cool the cutting environment and remove the chips generated during cutting. The cutting fluid entering the annular slit 204 flows along the annular slit 204 to the throttling ring 230 to provide support for the drill body 200. When the cutting fluid flows to the throttling ring 230, it will be blocked by the throttling ring 230, which will reduce the flow rate of the cutting fluid and reduce the flow rate of the cutting fluid flowing out of the annular slit 204. This will significantly reduce the pressure drop in the annular slit 204 and make the support more stable.

[0054] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A deep hole drill for high-strength mold steel, used for drilling holes in high-strength mold steel, characterized in that: The drill bit body includes a cutting edge at one end. It has a fluid inlet channel and a return channel. The fluid inlet channel is eccentrically positioned relative to the drill bit body, while the return channel is coaxially positioned with the drill bit body. The area between the cutting edge and the borehole is called the cutting zone, and the fluid inlet channel connects to the return channel through the cutting zone. An annular slit is defined between the outer peripheral wall of the drill bit body and the inner peripheral wall of the borehole. A throttling ring is coaxially positioned on the drill bit body. The two ends of the fluid inlet channel along the axial direction of the drill bit body are called the first end and the second end, respectively. The throttling ring is located between the first end and the second end. The gap between the throttling ring and the inner peripheral wall of the borehole is smaller than the gap between the outer peripheral wall of the drill bit body and the inner peripheral wall of the borehole.

2. The deep hole drilling tool made of high-strength mold steel according to claim 1, characterized in that: The drill bit body includes a drill bit and a drill rod. The drill bit is located at one end of the drill rod and is coaxial with the drill rod. The cutting edge is located at the end of the drill bit away from the drill rod. A throttling ring is detachably installed on the drill bit. A first branch is opened on the drill rod, which is eccentrically positioned relative to the drill rod. A second branch is opened on the drill bit, which is eccentrically positioned relative to the drill bit and communicates with the first branch. The fluid inlet channel is defined by the first branch and the second branch. A return port is opened on the drill bit and extends through its axial direction. The return port communicates with the cutting area. The return channel is opened on the drill rod and is coaxial with the drill rod. The fluid inlet channel communicates with the return channel through the return port.

3. The deep hole drilling tool made of high-strength mold steel according to claim 2, characterized in that: Multiple guide blocks are spaced apart on the outer peripheral wall of the drill bit. The guide blocks are arranged along the axial direction of the drill bit and can contact the inner peripheral wall of the borehole.

4. A deep hole drill bit made of high-strength mold steel according to claim 2, characterized in that: Multiple connecting blocks are provided at one end of the throttle ring. The multiple connecting blocks are evenly distributed around the circumference of the throttle ring, and the connecting blocks are locked to the drill bit by bolts.

5. A deep hole drill bit made of high-strength mold steel according to claim 2, characterized in that: Multiple Tesla valves are evenly distributed on the inner circumferential wall of the throttling ring, and the multiple Tesla valves are installed in opposite directions on the inner circumferential wall of the throttling ring.

6. A deep hole drill bit made of high-strength mold steel according to claim 5, characterized in that: An adjusting ring is screwed onto the drill bit, and in the radial direction of the drill bit, the Tesla valve is located between the throttle ring and the adjusting ring and abuts against the outer peripheral wall of the adjusting ring.

7. A deep hole drill bit made of high-strength mold steel according to claim 2, characterized in that: It also includes an orifice oil feeder, which is coaxially mounted with the drill rod and sleeved on the drill rod. The orifice oil feeder abuts against the end face of the high-strength mold steel, and a sealing ring is provided between the two. The orifice oil feeder can deliver cutting fluid to the annular slit and the fluid inlet channel respectively.

8. A deep hole drill bit made of high-strength mold steel according to claim 7, characterized in that: The orifice oil supply device includes a housing and multiple connecting rods. The housing has an inlet with a high-pressure valve. The multiple connecting rods are evenly distributed around the central axis of the housing, and an annular chamber is defined between the housing and the multiple connecting rods. Multiple one-way components are evenly distributed along the axial direction of the drill rod. The one-way components include multiple one-way valves. The multiple one-way valves are evenly distributed in the circumferential direction of the drill rod. The one-way valves open only when the drill rod is in the housing, allowing the cutting fluid to enter the first branch.

9. A deep hole drill bit made of high-strength mold steel according to claim 8, characterized in that: The drill pipe has multiple mounting holes that are connected to the first branch. Each mounting hole corresponds to a one-way valve. The one-way valve includes a ball valve body and a protrusion. Both the ball valve body and the protrusion are arranged along the radial direction of the drill pipe and are fixedly connected. The ball valve body is installed in the mounting hole corresponding to it through a first elastic element. Part of the ball valve body is located in the first branch, while part of the ball valve body and the protrusion extend out of the mounting hole. The protrusion can abut against the connecting rod. The surface area of ​​the ball valve body located in the first branch is greater than the surface area of ​​the ball valve body extending out of the mounting hole.

10. A drilling process for a high-strength mold steel deep hole drill bit, utilizing a high-strength mold steel deep hole drill bit as described in any one of claims 1 to 9, characterized in that, Includes the following steps: S10, align the drill body with the high-strength mold steel hole to be machined, and feed and cut through the cutting edge; S20, synchronously delivers cutting fluid into the fluid inlet channel and the annular slit; S30, the cutting fluid entering the inlet channel is transported to the cutting area and returned through the return channel to cool the cutting environment and remove the chips generated during cutting. The cutting fluid that enters the annular slit flows along the annular slit to the throttling ring, providing support for the drill bit body.

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