A self-chip-removal drill for deep hole machining

Abstract

The present application relates to the technical field of drilling tools, in particular to a self-chip-removal drilling tool for deep hole machining, comprising an outer tube, an inner tube and a drill bit; the outer tube is internally provided with a mounting hole, the front end of the outer tube is a cutting end, and the rear end of the outer tube is provided with a liquid inlet groove; the inner tube is arranged in the mounting hole, the inner cavity of the inner tube constitutes a chip removal channel, an annular flow channel is formed between the outer wall of the inner tube and the inner wall of the mounting hole, the rear end of the inner tube is provided with a plurality of crescent grooves, the drill bit is connected to the inside of the front end of the outer tube, and an annular gap is formed between the drill bit and the inner wall of the outer tube, a plurality of helical grooves are arranged on the drill bit, the helical grooves are in communication with the annular flow channel and the annular gap at the same time, and the annular gap is in communication with the chip removal channel; when the cutting chip at the front end of the drill bit accumulates or the chip removal is not smooth, resulting in an increase in the rotational resistance moment of the drill bit, the drill bit can be elastically twisted in the circumferential direction relative to the outer tube, the flow of the cooling liquid flowing through the helical grooves is reduced, the flow of the cooling liquid flowing through the crescent grooves is increased, and the self-adaptive adjustment of the chip removal capacity under abnormal working conditions is realized.

Description

Technical Field

[0001] This invention relates to the field of drilling tools, and in particular to a self-drilling drill for deep hole machining. Background Technology

[0002] Deep hole machining typically refers to hole machining techniques where the ratio of hole depth to hole diameter is greater than or equal to 5 or even 10. It has wide applications in aerospace, automotive manufacturing, mold making, energy equipment, and defense industries. Currently, self-drum drilling tools are commonly used for deep hole machining. Their working principle is to use high-pressure cutting fluid to force the chips generated in the cutting zone to be discharged through internal or external chip removal channels of the drill bit, thereby achieving continuous machining.

[0003] However, during deep hole machining, the generation and removal of chips is a dynamic and fluctuating process. The diameter of the oil passage in existing drill bits is a fixed value. Once chips accumulate at the front end due to uneven material distribution or tool wear during machining, the chip removal resistance will increase sharply. Since the oil passage cannot be adjusted in real time, the chips cannot be removed in time, which leads to continuous blockage of the chip removal channel and ultimately damage to the drill bit. Summary of the Invention

[0004] Therefore, it is necessary to provide a self-drilling tool for deep hole machining to address the technical problem that current self-drilling tools are prone to continuous blockage of the chip removal channel.

[0005] The above objectives are achieved through the following technical solutions: A self-ejecting chip removal drill for deep hole machining includes an outer tube, an inner tube, and a drill bit. The outer tube has an axially extending mounting hole, defining the axis of the outer tube as extending in a front-to-back direction. The front end of the outer tube is the cutting end, and the rear end has a fluid inlet groove. The inner tube is coaxially disposed within the mounting hole, its inner cavity forming a chip removal channel. An annular flow channel is formed between the outer wall of the inner tube and the inner wall of the mounting hole. The rear end of the inner tube has multiple rearwardly inclined crescent-shaped grooves, which communicate with the chip removal channel. The annular flow channel and the crescent-shaped grooves are both connected to the fluid inlet groove. The drill bit is detachably connected to the front end of the outer tube, and the drill bit is flush with the inner wall of the outer tube. An annular gap is formed between the inner tube and the outer tube. The front end of the inner tube is inserted into the rear end of the drill bit and sealed. The drill bit is provided with multiple circumferentially distributed spiral grooves. The spiral grooves are connected to both the annular flow channel and the annular gap. The annular gap is connected to the chip removal channel. When the chips accumulate at the front end of the drill bit or the chip removal is not smooth, causing the rotational resistance torque on the drill bit to increase, the drill bit can generate circumferential elastic torsion relative to the outer tube. This causes the liquid flow area of ​​the spiral grooves to automatically decrease, the flow rate of coolant flowing through the spiral grooves into the annular gap to decrease, and the flow rate of coolant flowing through the crescent grooves into the chip removal channel to increase, thereby enhancing the suction effect in the chip removal channel.

[0006] Furthermore, a connector is coaxially provided at the rear end of the outer tube. The connector is used to connect to an external feeding mechanism. The connector is provided with a liquid inlet, which corresponds to and communicates with the liquid inlet groove. A locking nut is coaxially sleeved on the outer tube. The locking nut is used to connect with the connector by threads. A clamping sleeve is also provided between the connector and the outer tube. The clamping sleeve has a split structure. The locking nut can push the clamping sleeve along the axial direction of the outer tube, so that the clamping sleeve is inserted into the interior of the connector, thereby the clamping sleeve can retract and clamp the outer tube.

[0007] Furthermore, the clamping sleeve has an outer conical surface, and the connector has an inner conical surface, with the outer conical surface and the inner conical surface slidingly engaging along the axial direction of the outer tube.

[0008] Furthermore, the rear end of the outer tube is provided with an adjustment component, which enables the inner tube to move back and forth relative to the drill bit, thereby adjusting the fluid flow area of ​​the spiral groove. The adjustment component includes a threaded sleeve fitted on the outer tube, which is fixedly connected to the rear of the connector. The rear end of the inner tube is threadedly connected with a first adjusting nut and a second adjusting nut. The first adjusting nut is located in front of the second adjusting nut. A screw ring is clamped between the first adjusting nut and the second adjusting nut. The screw ring is threadedly connected to the inside of the threaded sleeve and can rotate relative to the first adjusting nut and the second adjusting nut. By rotating the screw ring, the inner tube can be moved back and forth relative to the drill bit.

[0009] Furthermore, a positioning sleeve is also threadedly connected inside the screw sleeve. The positioning sleeve is sleeved outside the second adjusting nut, and the positioning sleeve and the screw ring are engaged in a stop-fitting manner along the axial direction of the outer tube.

[0010] Furthermore, multiple positioning platforms are evenly distributed circumferentially inside the front end of the outer tube. The positioning platforms are detachably installed inside the front end of the outer tube by bolts. The positioning platforms are used to position the drill bit so that the drill bit is centered inside the front end of the outer tube.

[0011] Furthermore, the drill bit is connected to the front end of the outer tube via a thread, and the direction of the thread is configured so that the drill bit can automatically tighten into the outer tube under the action of the rotational resistance torque.

[0012] Furthermore, the drill bit has a cutting edge at its front end, which is used to cut deep holes. The drill bit also has an opening, and the annular gap is connected to the chip removal channel through the opening.

[0013] Furthermore, the crescent groove is provided in two sets, front and back, each set containing multiple crescent grooves evenly distributed along the circumference of the inner tube, and the two sets of crescent grooves are arranged alternately along the circumference of the inner tube.

[0014] Furthermore, the drill bit is made of an elastic metal material, namely spring steel.

[0015] The beneficial effects of this invention are: The self-ejecting chip removal drill bit for deep hole machining provided by this invention prevents the drill bit from undergoing circumferential elastic torsion due to the rotational resistance torque during normal cutting. However, when chip accumulation at the drill bit's tip or poor chip removal increases the rotational resistance torque, the drill bit will undergo circumferential elastic torsion relative to the outer tube. This automatically reduces the coolant flow area of ​​the spiral groove, decreasing the amount of coolant flowing to the cutting end while allowing more coolant to be injected at high speed into the chip removal channel through the crescent groove. This enhances the suction force within the chip removal channel, preventing continuous chip accumulation at the bottom of the hole and utilizing the instantaneously increased suction force to remove the chips. This achieves adaptive adjustment of chip removal capacity under abnormal working conditions, preventing damage to the drill bit. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of a self-discharging chip drill for deep hole machining according to an embodiment of the present invention; Figure 2 A side view of a self-discharging chip drill for deep hole machining provided in an embodiment of the present invention; Figure 3 for Figure 2 Schematic diagram of the AA section; Figure 4 for Figure 3 Enlarged view of the structure at point X; Figure 5 for Figure 3 Enlarged view of the structure at point Y in the middle; Figure 6 This is a schematic diagram of the drill bit structure in a self-discharging chip drill for deep hole machining according to an embodiment of the present invention; Figure 7 This is a schematic diagram of the outer tube structure of a self-drilling deep hole drilling tool provided in an embodiment of the present invention; Figure 8 This is a schematic diagram of the connector and threaded sleeve in a self-drilling tool for deep hole machining provided in an embodiment of the present invention.

[0017] in: 100. Outer tube; 101. Positioning platform; 102. First internal thread; 200. Inner tube; 201. Crescent groove; 300. Drill bit; 301. Cutting edge; 302. Opening; 303. Spiral groove; 304. First external thread; 305. Liquid inlet groove; 400. Connector; 401. Clamping sleeve; 402. Locking nut; 403. Liquid inlet; 500. Screw sleeve; 501. First adjusting nut; 502. Screw ring; 503. Positioning sleeve; 504. Second adjusting nut. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings.

[0019] like Figures 1 to 8 As shown in the figure, an embodiment of the present invention provides a self-discharging chip removal drill for deep hole machining, including an outer tube 100, an inner tube 200, and a drill bit 300. The outer tube 100 has an axially extending mounting hole, defining the axis of the outer tube 100 as extending in the front-rear direction. The front end of the outer tube 100 is the cutting end, and the rear end of the outer tube 100 has a fluid inlet groove 305, which is an annular groove. The inner tube 200 is coaxially disposed within the mounting hole, and its inner cavity forms a chip removal channel. An annular flow channel is formed between the outer wall of the inner tube 200 and the inner wall of the mounting hole. The rear end of the inner tube 200 has multiple rearwardly inclined crescent grooves 201, which communicate with the chip removal channel. The annular flow channel and the crescent grooves 201 are both connected to the fluid inlet groove 305. The drill bit 300 is detachably connected to the outer tube. Inside the front end of the inner tube 100, an annular gap is formed between the drill bit 300 and the inner wall of the outer tube 100. The front end of the inner tube 200 is inserted into the rear end of the drill bit 300 and sealed. The drill bit 300 is provided with a plurality of circumferentially distributed spiral grooves 303. The spiral grooves 303 are simultaneously connected to the annular flow channel and the annular gap. The annular gap is connected to the chip removal channel. When the chips at the front end of the drill bit 300 accumulate or chip removal is obstructed, causing the rotational resistance torque on the drill bit 300 to increase, the drill bit 300 can generate circumferential elastic torsion relative to the outer tube 100. This causes the liquid flow area of ​​the spiral grooves 303 to automatically decrease, the flow rate of coolant flowing through the spiral grooves 303 into the annular gap to decrease, and the flow rate of coolant flowing through the crescent grooves 201 into the chip removal channel to increase, thereby enhancing the suction effect in the chip removal channel.

[0020] Specifically, the spiral groove 303 has circular grooves at both ends to facilitate machining; and the spiral groove 303 is radially penetrating the drill bit 300. During use, a portion of the coolant entering through the inlet groove 305 enters the annular flow channel, passes through the spiral groove 303 into the annular gap, and is then sprayed towards the front end of the drill bit 300. The coolant carries the chips through the entire chip removal channel of the inner tube 200 and is discharged backward. The other portion enters the chip removal channel through the crescent groove 201 and forms a jet, creating a low-pressure zone in the chip removal channel behind the outlet of the crescent groove 201. This low-pressure zone increases the pressure difference before and after the chip removal channel, thereby applying a suction force to the chips and coolant at the front end of the drill bit 300, causing the coolant to carry the cuttings and accelerate outward through the chip removal channel.

[0021] When the drill bit 300 is cutting normally, the resistance torque experienced by the drill bit 300 will not cause it to undergo circumferential elastic torsion. When the accumulation of chips at the tip of the drill bit 300 or poor chip removal leads to an increase in the rotational resistance torque experienced by the drill bit 300, the drill bit 300 will undergo circumferential elastic torsion relative to the outer tube 100. This will automatically reduce the fluid flow area of ​​the spiral groove 303, thereby reducing the amount of coolant flowing to the cutting end and allowing more coolant to be injected at high speed into the chip removal channel through the crescent groove 201. This will enhance the suction force within the chip removal channel, thus preventing chips from continuously accumulating at the bottom of the hole and using the instantaneously increased suction force to remove the chips. This achieves adaptive adjustment of chip removal capacity under abnormal working conditions, preventing damage to the drill bit.

[0022] Furthermore, a connector 400 is coaxially provided at the rear end of the outer tube 100. The connector 400 is used to connect to an external feeding mechanism. The connector 400 is provided with a liquid inlet 403, which corresponds to and communicates with the liquid inlet groove 305. A locking nut 402 is coaxially sleeved on the outer tube 100. The locking nut 402 is used to connect with the connector 400 by threads. A clamping sleeve 401 is also provided between the connector 400 and the outer tube 100. The clamping sleeve 401 has a split structure. The locking nut 402 can push the clamping sleeve 401 along the axial direction of the outer tube 100, so that the clamping sleeve 401 is inserted into the interior of the connector 400, thereby the clamping sleeve 401 can retract and clamp the outer tube 100. The process of locking the nut 402 to the connector 400 by threading it together allows the clamping sleeve 401 to contract and clamp the outer tube 100, thereby achieving a fixed connection between the connector 400 and the outer tube 100. This locking method is stable and reliable, and the segmented structure can adapt to the slight dimensional deviation of the outer tube 100, achieving uniform force application and avoiding the outer tube 100 from being crushed or out of round due to excessive local stress.

[0023] Specifically, the external feed mechanism is the machine tool spindle, which provides the driving force to feed the outer tube 100 in the back-and-forth direction. The liquid inlet 403 can be connected to the coolant storage tank through an external pipeline.

[0024] Furthermore, the clamping sleeve 401 has an outer conical surface, and the connector 400 has an inner conical surface. The outer conical surface and the inner conical surface slide in fit along the axial direction of the outer tube 100. The conical surface fit can efficiently convert the axial locking force of the locking nut 402 into a uniform radial clamping force.

[0025] Furthermore, the outer tube 100 is provided with an adjustment component at its rear end. The adjustment component enables the inner tube 200 to move back and forth relative to the drill bit 300, thereby adjusting the liquid flow area of ​​the spiral groove 303. The adjustment component includes a threaded sleeve 500 sleeved on the outer tube 100. The threaded sleeve 500 is fixedly connected to the rear of the connector 400. The rear end of the inner tube 200 is threadedly connected to a first adjusting nut 501 and a second adjusting nut 504. The first adjusting nut 501 is located in front of the second adjusting nut 504. A screw ring 502 is held between the first adjusting nut 501 and the second adjusting nut 504. The screw ring 502 is threadedly connected to the inside of the threaded sleeve 500 and can rotate relative to the first adjusting nut 501 and the second adjusting nut 504. By rotating the screw ring 502, the inner tube 200 can be moved back and forth relative to the drill bit 300.

[0026] Specifically, the axial end face of the screw ring 502 is provided with an insertion hole for inserting a pin, thereby facilitating the rotation of the screw ring 502 within the screw sleeve 500. By rotating the screw ring 502 to move it back and forth, and using the clamping of the first adjusting nut 501 and the second adjusting nut 504, the inner tube 200 can be moved back and forth relative to the drill bit 300. When the inner tube 200 moves backward, its front end will block the spiral groove 303 on the drill bit 300, thereby reducing the fluid flow area; thus, the initial flow distribution ratio (i.e., the ratio of the liquid flow rate of the spiral groove 303 to the liquid flow rate of the crescent groove 201) can be preset according to the actual working conditions such as the machining diameter and material of the deep hole, improving the versatility of this self-discharging drill for deep hole machining.

[0027] Furthermore, a positioning sleeve 503 is threadedly connected inside the threaded sleeve 500. The positioning sleeve 503 is fitted outside the second adjusting nut 504, and the positioning sleeve 503 and the threaded ring 502 are engaged in a stop-fitting manner along the axial direction of the outer tube 100. The positioning sleeve 503 can prevent the threaded sleeve 500 from axially moving during working vibration, so as to keep the relative position of the front end of the inner tube 200 and the spiral groove 303 stable.

[0028] Furthermore, multiple positioning platforms 101 are evenly distributed circumferentially inside the front end of the outer tube 100. These positioning platforms 101 are detachably mounted inside the front end of the outer tube 100 using bolts. The positioning platforms 101 are used to position the drill bit 300, ensuring that the drill bit 300 is centered inside the front end of the outer tube 100. The positioning platforms 101 ensure the coaxiality of the drill bit 300 and the outer tube 100 by centering the drill bit 300 inside the front end of the outer tube 100; and the detachable mounting of the positioning platforms 101 facilitates the assembly and disassembly of the drill bit 300.

[0029] Furthermore, the drill bit 300 is threaded to the front end of the outer tube 100. The direction of the thread is configured so that the drill bit 300 can automatically tighten into the outer tube 100 under the action of the rotational resistance torque. Thus, during the circumferential elastic torsion and subsequent reset of the drill bit 300, the threaded connection maintains a self-locking state, preventing loosening due to vibration or torque fluctuations. Specifically, the outer circumferential surface of the drill bit 300 is provided with a first external thread 304, and the front end of the outer tube 100 is provided with a first internal thread 102. The first external thread 304 and the first internal thread 102 are threadedly connected, facilitating the assembly and disassembly of the drill bit 300. When the drill bit 300 wears out, only the drill bit 300 needs to be replaced, without replacing the entire outer tube 100 and inner tube 200.

[0030] Furthermore, the drill bit 300 has a cutting edge 301 at its front end, which is used to cut the workpiece to form a deep hole. The drill bit 300 also has an opening 302, through which the annular gap communicates with the chip removal channel. The cutting edge 301 is a carbide tooth, which is responsible for cutting metal. The opening 302 allows the coolant in the annular gap to carry the chips into the chip removal channel.

[0031] Furthermore, the crescent grooves 201 are provided in two sets, front and rear, each set containing multiple crescent grooves 201 evenly distributed along the circumference of the inner tube 200. The two sets of crescent grooves 201 are staggered along the circumference of the inner tube 200. This arrangement can avoid interference and energy cancellation between multiple coolant jets in the same cross section, thereby making the suction effect on the coolant in the chip removal channel more sustained and improving the suction effect. Each crescent groove 201 is a conical through hole, with its front end diameter larger than its rear end diameter. When the coolant passes through the crescent groove 201, it flows in from the flared end at the front end and flows out from the constricted end at the rear end, so that the coolant accelerates the formation of a jet.

[0032] Furthermore, the drill bit 300 is made of an elastic metal material, namely spring steel. This facilitates the circumferential elastic torsion of the drill bit 300 relative to the outer tube 100. The area on the drill bit 300 with the spiral groove 303 can be heat-treated. After appropriate heat treatment, the spring steel can generate elastic torsion under a large torque and return to its original shape after unloading.

[0033] Based on the above embodiments, the usage principle and working process of the embodiments of the present invention are as follows: First, based on the machining diameter of the deep hole and the material of the workpiece, the axial position of the inner tube 200 in the outer tube 100 is adjusted by adjusting the component, so that the front end of the inner tube 200 forms a predetermined degree of obstruction on the spiral groove 303 on the drill bit 300, thereby preset the initial flow distribution ratio between the spiral groove 303 and the crescent groove 201.

[0034] Then, the workpiece to be processed is driven to rotate by the machine tool, and the outer tube 100 is driven to make axial feed motion by the feed mechanism of the machine tool. Coolant is delivered to the inlet tank 305 through the external pipeline. After entering the inlet tank 305, the coolant is divided into two paths. One path passes through the annular flow channel, the spiral groove 303 and the annular gap to reach the front end of the drill bit 300, which cools and lubricates the cutting area in the deep hole. Then, it carries the chips and enters the chip removal channel through the opening 302 and is discharged backward. The other path is injected at high speed into the chip removal channel through the crescent groove 201 at the rear end of the inner tube 200 to form a jet. A low-pressure area is generated at the rear end of the chip removal channel, which applies a suction force to the coolant carrying the chips to accelerate chip removal. When the chips accumulate at the front end of the drill bit 300 or chip removal is not smooth, it will cause the drill bit 300 to experience rotational resistance torque. As the volume increases, the drill bit 300 will undergo circumferential elastic torsion relative to the outer tube 100, causing the fluid passage area of ​​the spiral groove 303 to automatically decrease. This allows more coolant to flow through the crescent groove 201 into the chip removal channel, enhancing the suction force within the chip removal channel and forcefully sucking out the accumulated chips. After the accumulated chips are discharged, the rotational resistance torque on the drill bit 300 decreases accordingly. Under the action of its own elastic restoring force, the drill bit 300 resets, and the fluid passage area of ​​the spiral groove 303 automatically returns to its initial value, achieving automatic restoration of flow distribution. This cycle repeats continuously, enabling adaptive adjustment of chip removal capacity under abnormal working conditions throughout the deep hole machining process, thus preventing damage to the drill bit.

[0035] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still make modifications to the technical solutions described in the foregoing embodiments without creative effort, or make equivalent substitutions for some of the technical features. 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 self-discharging chip drill for deep hole machining, characterized in that, include: The outer tube has an axially penetrating mounting hole inside it, defining the axis of the outer tube as extending in the front-to-back direction. The front end of the outer tube is a cutting end, and the rear end of the outer tube is provided with a liquid inlet groove. The inner tube is coaxially disposed in the mounting hole. The inner cavity of the inner tube forms a chip removal channel. An annular flow channel is formed between the outer wall of the inner tube and the inner wall of the mounting hole. The rear end of the inner tube is provided with multiple backward-inclined crescent grooves. The crescent grooves are connected to the chip removal channel. The annular flow channel and the crescent grooves are both connected to the liquid inlet tank. The drill bit is detachably connected to the front end of the outer tube, and an annular gap is formed between the drill bit and the inner wall of the outer tube. The front end of the inner tube is inserted into the rear end of the drill bit and sealed. The drill bit is provided with multiple circumferentially distributed spiral grooves, which are simultaneously connected to the annular flow channel and the annular gap. The annular gap is connected to the chip removal channel. When the accumulation of chips at the tip of the drill bit or poor chip removal leads to an increase in the rotational resistance torque on the drill bit, the drill bit can undergo circumferential elastic torsion relative to the outer tube. This causes the liquid flow area of ​​the spiral groove to automatically decrease, reducing the flow rate of coolant flowing through the spiral groove into the annular gap, while increasing the flow rate of coolant flowing through the crescent groove into the chip removal channel, thereby enhancing the suction effect in the chip removal channel.

2. The self-discharging chip drill for deep hole machining according to claim 1, characterized in that, The outer tube has a connector coaxially mounted at its rear end. The connector is used to connect to an external feeding mechanism. The connector has a liquid inlet that corresponds to and communicates with the liquid inlet groove. A locking nut is coaxially mounted on the outer tube. The locking nut is used to connect to the connector via a thread. A clamping sleeve is also provided between the connector and the outer tube. The clamping sleeve has a split structure. The locking nut can push the clamping sleeve along the axial direction of the outer tube, so that the clamping sleeve is inserted into the interior of the connector, thereby allowing the clamping sleeve to retract and clamp the outer tube.

3. The self-discharging chip drill for deep hole machining according to claim 2, characterized in that, The clamping sleeve has an outer conical surface, and the connector has an inner conical surface. The outer conical surface and the inner conical surface slide together along the axial direction of the outer tube.

4. The self-discharging chip drill for deep hole machining according to claim 2, characterized in that, The outer tube has an adjustment component at its rear end, which allows the inner tube to move back and forth relative to the drill bit, thereby adjusting the fluid flow area of ​​the spiral groove. The adjustment component includes a threaded sleeve fitted on the outer tube, which is fixedly connected to the rear of the connector. The rear end of the inner tube is threadedly connected to a first adjusting nut and a second adjusting nut. The first adjusting nut is located in front of the second adjusting nut. A screw ring is clamped between the first adjusting nut and the second adjusting nut. The screw ring is threaded inside the threaded sleeve and can rotate relative to the first adjusting nut and the second adjusting nut. By rotating the screw ring, the inner tube can be moved back and forth relative to the drill bit.

5. The self-discharging chip drill for deep hole machining according to claim 4, characterized in that, The threaded sleeve is also threadedly connected to a positioning sleeve, which is sleeved outside the second adjusting nut and is engaged with the threaded ring along the axial direction of the outer tube.

6. The self-discharging chip drill for deep hole machining according to claim 1, characterized in that, Multiple positioning platforms are evenly distributed circumferentially inside the front end of the outer tube. The positioning platforms are detachably installed inside the front end of the outer tube by bolts. The positioning platforms are used to position the drill bit so that the drill bit is centered inside the front end of the outer tube.

7. The self-discharging chip drill for deep hole machining according to claim 1, characterized in that, The drill bit is connected to the front end of the outer tube by a thread, and the direction of the thread is configured so that the drill bit can be automatically tightened into the outer tube under the action of the rotational resistance torque.

8. The self-discharging chip drill for deep hole machining according to claim 1, characterized in that, The drill bit has a cutting edge at its front end, which is used to cut deep holes. The drill bit also has an opening, and the annular gap is connected to the chip removal channel through the opening.

9. The self-discharging chip drill for deep hole machining according to claim 1, characterized in that, The crescent groove is provided in two sets, front and back. Each set contains multiple crescent grooves evenly distributed along the circumference of the inner tube. The two sets of crescent grooves are arranged alternately along the circumference of the inner tube.

10. The self-discharging chip drill for deep hole machining according to claim 1, characterized in that, The drill bit is made of an elastic metal material, namely spring steel.

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