Round steel center hole drilling device

Abstract

The invention discloses a round steel center hole drilling device and belongs to the technical field of round steel center hole drilling, the round steel center hole drilling device comprises a feeding assembly, a punching assembly and a discharging assembly, the punching assembly comprises a drilling unit, a workpiece rotation driving unit and a plurality of rollers which are sequentially arranged at the top of a conveying frame, and the drilling unit comprises a drill bit; the drill bit is fixedly connected with a telescopic part of the telescopic power device, a shell of the telescopic power device is in transmission connection with the second rotating power device, the workpiece rotating driving unit comprises a mounting base fixedly connected with the fixing frame, a chuck is rotationally connected to the mounting base, and a chuck body of the chuck is in transmission connection with the first rotating driving device fixed to the mounting base. The ends of every two adjacent rollers are in transmission connection, one roller is in transmission connection with a third rotary driving device, and the diameter of each roller is gradually increased from the middle to the two sides. By means of the round steel center hole drilling device of the structure, it can be guaranteed that a drilled hole is located in the center of the end face of round steel.

Description

Technical Field

[0001] The invention belongs to the technical field of round steel center hole drilling, and in particular relates to a round steel center hole drilling device. Background Art

[0002] Round steel refers to a solid long steel strip with a circular cross section, which is used to manufacture mechanical parts or seamless steel pipe blanks. Round steel needs to be turned during processing, and in order to facilitate lathe clamping, a center hole needs to be processed on the end face of the round steel. In the prior art, drilling is mainly performed in the center of the round steel ingot by a drilling device, but the drilling device has the following problems when used: Since the round steel may bend during production, the center hole is not in the center of the round steel end face during processing, and it is impossible to check all of them during the quality inspection process or the inspection accuracy is not enough, resulting in the round steel after drilling cannot be used in some occasions with higher requirements due to the inaccurate position of the center hole.

[0003] In order to solve the above problems, it is necessary to provide a new type of round steel center hole drilling device. Summary of the invention

[0004] The object of the present invention is to provide a device for drilling a center hole of a round steel, which can ensure that the drilled hole is located in the middle of the end surface of the round steel.

[0005] To achieve the above-mentioned objectives, the present invention provides a round steel center hole drilling device, comprising a loading component, a punching component and a unloading component, the punching component comprising a drilling unit, a workpiece rotation drive unit and a plurality of rollers which are sequentially arranged on the top of a conveying frame, the drilling unit comprising a drill bit, the drill bit being fixedly connected to the telescopic portion of a telescopic power device, the outer shell of the telescopic power device being transmission-connected to a second rotation power device, the outer shell of the telescopic power device being rotationally connected to a power box located on the conveying frame, the workpiece rotation drive unit comprising a mounting seat fixedly connected to the fixed frame, a chuck being rotationally connected to the mounting seat, a chuck body of the chuck being transmission-connected to a first rotation drive device fixed on the mounting seat, the ends of two adjacent rollers being transmission-connected, one of the rollers being transmission-connected to a third rotation drive device, and the diameter of the rollers gradually increasing from the middle to both sides.

[0006] Preferably, a pressure roller assembly is also provided on the conveying frame, and the pressure roller assembly includes a support frame fixedly connected to the conveying frame, a vertically arranged lifting drive device is fixedly connected to the support frame, the telescopic end of the lifting drive device is fixedly connected to the mounting frame, a pressure roller is rotatably connected to the mounting frame, and the pressure roller is parallelly arranged above a roller wheel close to the mounting seat.

[0007] Preferably, a first self-centering steady rest and a second self-centering steady rest are further provided on the conveying rack. The first self-centering steady rest and the second self-centering steady rest are respectively located between two roller wheels. The distance from the first self-centering steady rest to the mounting seat is less than the distance from the second self-centering steady rest to the mounting seat. The first self-centering steady rest and the second self-centering steady rest are both on the same straight line as the roller wheels.

[0008] Preferably, the loading assembly includes a storage rack and a material lifting rack. The top surface height of the storage rack gradually decreases from the end far away from the material lifting rack to the end close to the material lifting rack. The material lifting rack includes a bracket, a fixing plate and a lifting plate. There are multiple fixing plates which are fixedly connected to the top surface of the bracket. Two lifting plates are provided between adjacent two fixing plates. The lifting plates are arranged parallel to the fixing plates. The lifting plates are fixedly connected to the telescopic part of a hydraulic cylinder vertically fixed on the bracket. The top surfaces of the fixing plate and the lifting plate are both stepped. The top surface of each step on the fixing plate and the lifting plate is an inclined surface inclined downward towards the conveying rack. The step corners on the fixing plate and the lifting plate are arranged staggeredly.

[0009] Preferably, the ends of adjacent two roller wheels are connected by a first chain in a transmission manner. One of the roller wheels is connected to a third rotation driving device by a second chain in a transmission manner. A chain cover corresponding to the first chain and the second chain is provided on the conveying rack. The top surface of the chain cover is smoothly connected to the top surface of the fixing plate.

[0010] Preferably, the unloading assembly includes an unloading rack and a turning plate. The top surface height of the unloading rack gradually decreases from the end close to the conveying rack to the end far away from the conveying rack. There are multiple turning plates. Each turning plate is located between two roller wheels. The turning plate includes a material lifting section and a driving section which are integrally connected. The end of the material lifting section far away from the driving section is rotatably connected to the conveying rack through a rotating connecting seat. The top end of the rotating connecting seat is provided with a rotating shaft which is rotatably connected to one end of the material lifting section. The rotating shaft is flush with the top end of the unloading rack. The height of the end of the material lifting section connected to the driving section is lower than the height of the roller wheels. The driving section is fixedly connected to the bottom surface of the material lifting section. The bottom of each driving section is connected to the same connecting rod. The connecting rod is hinged to the telescopic part of a turning driving device.

[0011] Preferably, a groove is provided on the conveying rack between the drilling unit and the workpiece rotation driving unit. The bottom end of the groove is provided with an opening. A limiting block corresponding to the central through hole of the chuck body is provided in the groove. A through groove opposite to the drill bit is provided on the limiting block.

[0012] Therefore, the present invention adopts a round steel center hole drilling device with the above structure, and has the following beneficial effects: 1. The rotation of the chuck and the drill bit can ensure that the drilled hole is located exactly in the center of the end face of the round steel: when the drill bit is not on the same straight line as the central axis of the round steel, a round hole will not be drilled on the end face of the round steel, thereby ensuring the position accuracy of the center hole.

[0013] 2. The use of the pressure roller assembly can realize the conveying of round steel with a shorter length, and thus enable the device to process the center hole of short round steel.

[0014] 3. The first self-centering center rest is used to center the round steel with a shorter length, and the second self-centering center rest is used to center the round steel with a longer length, improving the position stability of the round steel before and during contact with the drill bit.

[0015] The technical solution of the present invention will be further described in detail below with reference to the drawings and embodiments. Description of the Drawings

[0016] Figure 1 It is a schematic structural diagram of an embodiment of a round steel center hole drilling device of the present invention; Figure 2 It is a schematic structural diagram of an embodiment of a workpiece rotation drive unit in a round steel center hole drilling device of the present invention; Figure 3 It is a schematic structural diagram of an embodiment of a pressure roller assembly in a round steel center hole drilling device of the present invention; Figure 4 It is a schematic structural diagram of an embodiment of a turning plate in a round steel center hole drilling device of the present invention Figure 5 It is a schematic structural diagram of an embodiment of a first self-centering center rest in a round steel center hole drilling device of the present invention.

[0017] In the figure: 1. Drilling unit; 101. Drill bit; 102. Telescopic power device; 103. Second rotary power device; 104. Power box; 2. Workpiece rotation drive unit; 201. Mounting seat; 202. Chuck; 203. First rotary drive device; 3. Roller; 4. Sprocket; 5. Chain cover; 6. Groove; 7. Opening; 8. Limit block; 9. Pressure roller assembly; 901. Support frame; 902. Lifting drive device; 903. Pressure roller; 904. Mounting frame; 10. First self-centering steady rest; 1001. Housing; 1002. Oil cylinder; 1003. Lifting frame; 1004. Bottom wheel; 1005. First convex column; 1006. Transmission plate; 1007. Arc-shaped groove; 1008. Connecting groove; 1009. Claw arm; 1010. Side wheel; 1011. Second convex column; 11. Second self-centering steady rest; 12. Storage rack; 13. Material lifting rack; 131. Support; 132. Fixed plate; 133. Lifting plate; 14. Material discharging rack; 15. Flipping plate; 151. Material lifting section; 152. Driving section; 16. Rotary connecting seat; 17. Rotating shaft; 18. Connecting rod; 19. Flipping drive device; 20. Conveyor rack. Detailed implementation manners

[0018] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0019] In order to make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific implementation manners. Embodiment

[0020] Refer to Figures 1-5As shown, this embodiment provides a round steel center hole drilling device, including a feeding assembly, a punching assembly and a unloading assembly, and the punching assembly includes a drilling unit 1, a workpiece rotation drive unit 2 and a plurality of rollers 3 arranged in sequence on the top of the conveying frame 20. The drilling unit 1 includes a drill bit 101, and the drill bit 101 is fixedly connected to the telescopic part of the telescopic power device 102. The telescopic power device 102 can be a hydraulic telescopic cylinder connected to a gasoline base station, and the drill bit 101 and the telescopic part of the telescopic power device 102 can be detachably connected to facilitate the replacement of the drill bit 101. The outer shell of the telescopic power device 102 is transmission-connected to the second rotating power device 103, and the second rotating power device 103 can be a motor, and the transmission connection method can be a chain connection. The outer shell of the telescopic power device 102 is rotationally connected to the power box 104 located on the conveying frame 20, and the power box 104 is used to realize the installation and positioning of the telescopic power device 102. The second rotating power device 103 can drive the telescopic power device 102 to rotate and thus the drill bit 101 to rotate. During the rotation of the drill bit 101, it can be telescoped under the drive of the telescopic power device 102, and the telescopic power device 102 is used to control the drilling depth.

[0021] The workpiece rotation driving unit 2 includes a mounting seat 201 fixedly connected to a fixed frame, and a chuck 202 is rotatably connected to the mounting seat 201, and the chuck 202 is used to clamp the round steel. The chuck body of the chuck 202 is transmission-connected to a first rotation driving device 203 fixed to the mounting seat 201, and the first rotation driving device 203 can be a motor, and the first rotation driving device 203 can drive the chuck 202 to rotate.

[0022] The diameter of the roller 3 gradually increases from the middle to both sides, so that the round steel is more stable when being transported on the roller 3. When in use, after the roller 3 transports the round steel to the right place, the chuck 202 can clamp the round steel, and the drill bit 101 can process the center hole of the round steel. The ends of two adjacent rollers 3 are connected by transmission, and the transmission connection method can be connected by a first chain transmission. One of the rollers 3 is connected by transmission with the third rotary drive device, and the transmission connection method can be connected by a second chain transmission, and the third rotary drive device can be a motor. A sprocket 4 compatible with the first chain and / or the second chain structure is fixedly provided on one end of the roller 3 and the output shaft of the third rotary drive device. A chain cover 5 corresponding to the first chain and the second chain is provided on the conveying frame 20, and the chain cover 5 can protect the first chain and the second chain.

[0023] The conveying rack 20 is provided with a groove 6 located between the drilling unit 1 and the workpiece rotation driving unit 2. The bottom end of the groove 6 is provided with an opening 7, and the opening 7 can discharge the round steel chips falling into the groove 6 during the central hole machining process. A limiting block 8 corresponding to the central through hole of the chuck body is arranged in the groove 6, and a through groove opposite to the drill bit 101 is arranged on the limiting block 8. The limiting block 8 can limit the round steel, ensure the stability of the final position of the round steel conveying, and further ensure that the machining depth of the central hole is only controlled by the telescopic power device 102, ensuring the accuracy of the machining depth of the central hole.

[0024] During use, the rotation of the roller 3 is used to convey the round steel. When the round steel is conveyed to the limiting block 8, the chuck 202 is activated to clamp the round steel. Subsequently, the first rotation power device and the second rotation power device 103 are activated to rotate the round steel and the drill bit 101. At the same time, the telescopic power device 102 is activated to drive the drill bit 101 to drill into the round steel, completing the machining of the central hole. During the machining of the central hole, as long as a round hole is drilled, it can be ensured that the round hole is located at the center of the end face of the round steel. When the round steel is bent to a certain extent due to unqualified production quality and the central axis of the drill bit 101 and the round steel are not on the same straight line, the drill bit 101 cannot drill a round hole. At this time, the operator can clearly identify the unqualified product and remove it.

[0025] In a further preferred solution, the conveying rack 20 is further provided with a pressure roller assembly 9. The pressure roller assembly 9 includes a support frame 901 fixedly connected to the conveying rack 20, and a vertically arranged lifting driving device 902 is fixedly connected to the support frame 901. The end of the telescopic part of the lifting driving device 902 is fixedly connected to the mounting frame 904. The lifting driving device 902 can be a cylinder, a hydraulic cylinder or an electric telescopic rod. A pressure roller 903 is rotatably connected to the mounting frame 904, and the pressure roller 903 is arranged parallel above one roller 3 close to the mounting seat 201.

[0026] During use, the pressure roller 903 is used to press the short round steel towards the roller 3, and then the rotation of the roller 3 is used to pinch and convey the short round steel, avoiding the situation that the roller 3 cannot convey the round steel forward due to the short length and light weight of the round steel.

[0027] Further preferred solution, the conveying frame 20 is further provided with a first self-centering center rest 10 and a second self-centering center rest 11. The first self-centering center rest 10 and the second self-centering center rest 11 are respectively located between two rollers 3. The distance from the first self-centering center rest 10 to the mounting seat 201 is less than the distance from the second self-centering center rest 11 to the mounting seat 201. The first self-centering center rest 10 and the second self-centering center rest 11 are both on the same straight line as the rollers 3. During use, the first self-centering center rest 10 is used to center and support the shorter round steel, and the second self-centering center rest 11 is used to center and support the longer round steel, improving the position stability of the round steel before and when it contacts the drill bit 101.

[0028] Wherein, both the first self-centering center rest 10 and the second self-centering center rest 11 include a housing 1001 fixedly connected to the conveying frame 20. The bottom end of the housing 1001 is fixedly connected with an oil cylinder 1002. The top end of the telescopic part of the oil cylinder 1002 is connected to a lifting frame 1003 located inside the housing 1001. The top end of the lifting frame 1003 passes through the housing 1001 and is rotatably connected to a bottom wheel 1004. Both sides of the lifting frame 1003 are respectively slidably connected to an arc-shaped groove 1007 on a transmission plate 1006 through a first convex column 1005. The bottom end of the transmission plate 1006 is rotatably connected to the housing 1001 through a rotating shaft. The top end of the transmission plate 1006 is provided with a connecting groove 1008. The top of the housing 1001 is provided with claw arms 1009 symmetrically arranged on both sides of the bottom wheel 1004. The middle of the claw arms 1009 is rotatably connected to the housing 1001. The top end of the claw arms 1009 is rotatably connected to side wheels 1010. The bottom end of the claw arms 1009 is located inside the housing 1001, and the claw arms 1009 are slidably connected to the connecting groove 1008 through a second convex column 1011. When the first self-centering center rest 10 and the second self-centering center rest 11 are working, the oil cylinder 1002 drives the lifting frame 1003 to rise and fall, thereby realizing the lifting of the bottom wheel 1004 and the mutual approach or mutual separation between the two side wheels 1010. After the bottom wheel 1004 rises and the two side wheels 1010 approach each other, the centering and supporting effect on the round steel can be realized. After the bottom wheel 1004 descends and the two side wheels 1010 move away from each other, the release of the round steel can be realized.

[0029] Further preferred solution, the feeding component includes a storage rack 12 and a material lifting rack 13. The top surface height of the storage rack 12 gradually decreases from the end far away from the material lifting rack 13 to the end close to the material lifting rack 13, so that the round steel on the storage rack 12 can spontaneously move towards the material lifting rack 13 under the action of gravity. The material lifting rack 13 includes a bracket 131, a fixing plate 132 and a lifting plate 133. There are multiple fixing plates 132 which are fixedly connected to the top surface of the bracket 131, and the top surface of the fixing plate 132 is smoothly connected to the top surface of the chain cover 5. There are two lifting plates 133 between two adjacent fixing plates 132. The lifting plates 133 are arranged parallel to the fixing plates 132 and are fixedly connected to the telescopic part of the hydraulic cylinder vertically fixed on the bracket 131. The lifting plates 133 can perform lifting movements driven by the hydraulic cylinder. The top surfaces of the fixing plate 132 and the lifting plate 133 are both stepped. The top surface of each step on the fixing plate 132 and the lifting plate 133 is an inclined surface inclined downward towards the conveying rack 20, and the step corners on the fixing plate 132 and the lifting plate 133 are arranged staggeredly.

[0030] During use, the top surface width of each step of the fixing plate 132 and the lifting plate 133 is designed to only accommodate the length of one round steel. Each time the lifting plate 133 lifts the round steel, the round steel can move to a higher step of the fixing plate 132 under the action of the inclined surface. When the round steel moves to the highest step, the round steel rolls over the chain cover 5 under the action of the inclined surface and enters the roller 3.

[0031] Further preferred solution, the discharging component includes a discharging rack 14 and a turning plate 15. The top surface height of the discharging rack 14 gradually decreases from the end close to the conveying rack 20 to the end far away from the conveying rack 20. There are multiple turning plates 15, and each turning plate 15 is located between two rollers 3. The turning plate 15 includes a material lifting section 151 and a driving section 152 which are integrally connected. The material lifting section 151 is used to lift the round steel from the roller 3 and turn it onto the discharging rack 14, and the driving section 152 is used to transmit the turning power. One end of the material lifting section 151 far away from the driving section 152 is rotatably connected to the conveying rack 20 through a rotary connecting seat 16. The top of the rotary connecting seat 16 is provided with a rotating shaft 17 rotatably connected to one end of the material lifting section 151, and the rotating shaft 17 is flush with the top end of the discharging rack 14. The height of the end of the material lifting section 151 connected to the driving section 152 is lower than the height of the roller 3, and the driving section 152 is fixedly connected to the bottom surface of the material lifting section 151. The bottom of each driving section 152 is connected to the same connecting rod 18, and the connecting rod 18 is hinged to the telescopic part of the turning driving device 19.

[0032] In use, the flipping drive device 19 can be a hydraulic cylinder. The telescopic part of the hydraulic cylinder drives the connecting rod 18 to push the connecting rod 18, causing the end of the material lifting section 151 connected to the drive section 152 to tilt upward, thereby flipping the round steel on the roller 3 onto the blanking rack 14. A conveyor belt or a collection box is arranged at the blanking rack 14 to achieve the conveying, transfer, or collection of the round steel.

[0033] Therefore, by adopting the above-described structure for a round steel center hole drilling device, the present invention can ensure that the drilled hole is located exactly in the center of the end face of the round steel.

[0034] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention.

[0035] The above-described embodiments are only for describing the preferred mode of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solution of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A device for drilling a center hole of round steel, characterized in that: The invention comprises a loading assembly, a punching assembly and a unloading assembly, wherein the punching assembly comprises a drilling unit (1), a workpiece rotation driving unit (2) and a plurality of rollers (3) which are sequentially arranged on the top of a conveying frame (20), the drilling unit (1) comprises a drill bit (101), the drill bit (101) is fixedly connected to the telescopic part of a telescopic power device (102), the housing of the telescopic power device (102) is transmission-connected to a second rotation power device (103), the housing of the telescopic power device (102) is connected to a power box located on the conveying frame (20), and the housing of the telescopic power device (102) is connected to a power box located on the conveying frame (20). (104) rotationally connected, the workpiece rotation driving unit (2) comprises a mounting seat (201) fixedly connected to the conveying frame (20), a chuck (202) is rotationally connected to the mounting seat (201), the chuck body of the chuck (202) is transmission-connected to a first rotation driving device (203) fixed to the mounting seat (201), the ends of two adjacent rollers (3) are transmission-connected, one of the rollers (3) is transmission-connected to a third rotation driving device, and the diameter of the rollers (3) gradually increases from the middle to both sides.

2. The round steel center hole drilling device according to claim 1, characterized in that: The conveying frame (20) is also provided with a pressure roller assembly (9), the pressure roller assembly (9) comprising a support frame (901) fixedly connected to the conveying frame (20), a vertically arranged lifting drive device (902) fixedly connected to the support frame (901), a telescopic end of the lifting drive device (902) fixedly connected to a mounting frame (904), a pressure roller (903) rotatably connected to the mounting frame (904), and the pressure roller (903) is arranged in parallel above one of the roller wheels (3) close to the mounting seat (201).

3. The round steel center hole drilling device according to claim 1, characterized in that: The conveying frame (20) is also provided with a first self-centering center frame (10) and a second self-centering center frame (11); the first self-centering center frame (10) and the second self-centering center frame (11) are respectively located between two rollers (3); the distance between the first self-centering center frame (10) and the mounting seat (201) is smaller than the distance between the second self-centering center frame (11) and the mounting seat (201); and the first self-centering center frame (10) and the second self-centering center frame (11) are both located on the same straight line as the rollers (3).

4. The round steel center hole drilling device according to claim 1, characterized in that: The loading assembly comprises a material storage rack (12) and a material lifting rack (13); the height of the top surface of the material storage rack (12) gradually decreases from an end away from the material lifting rack (13) to an end close to the material lifting rack (13); the material lifting rack (13) comprises a bracket (131), a fixed plate (132) and a lifting plate (133); the fixed plate (132) is provided with a plurality of and fixedly connected to the top surface of the bracket (131); two lifting plates (133) are provided between two adjacent fixed plates (132); The lifting plate (133) is arranged in parallel with the fixed plate (132), and the lifting plate (133) is fixedly connected to the telescopic part of the hydraulic cylinder vertically fixed on the bracket (131). The top surfaces of the fixed plate (132) and the lifting plate (133) are both step-shaped, and the top surfaces of each step on the fixed plate (132) and the lifting plate (133) are both inclined surfaces inclined downward toward the conveying frame (20), and the step corners on the fixed plate (132) and the lifting plate (133) are staggered.

5. The round steel center hole drilling device according to claim 4, characterized in that: The ends of two adjacent rollers (3) are connected via a first chain transmission, one of the rollers (3) is connected to the third rotation drive device via a second chain transmission, and the conveyor frame (20) is provided with a chain cover (5) corresponding to the first chain and the second chain, and the top surface of the chain cover (5) is smoothly connected to the top surface of the fixing plate (132).

6. The round steel center hole drilling device according to claim 1, characterized in that: The material unloading assembly comprises a material unloading frame (14) and a flip plate (15), the top surface height of the material unloading frame (14) gradually decreases from an end close to the conveying frame (20) to an end away from the conveying frame (20), a plurality of flip plates (15) are provided, each of the flip plates (15) is located between two of the rollers (3), and the flip plate (15) comprises an integrally connected material lifting section (151) and a driving section (152), and the end of the material lifting section (151) away from the driving section (152) is rotatably connected to the conveying frame (20) via a rotating connecting seat (16). The top of the rotating connecting seat (16) is provided with a rotating shaft (17) rotatably connected to one end of the lifting section (151), and the rotating shaft (17) is flush with the top of the unloading frame (14). The height of one end of the lifting section (151) connected to the driving section (152) is lower than the height of the roller (3). The driving section (152) is fixedly connected to the bottom surface of the lifting section (151), and the bottom of each driving section (152) is connected to the same connecting rod (18), and the connecting rod (18) is hinged to the telescopic part of the flip driving device (19).

7. The round steel center hole drilling device according to claim 1, characterized in that: The conveying frame (20) is provided with a groove (6) located between the drilling unit (1) and the workpiece rotation driving unit (2); an opening (7) is provided at the bottom end of the groove (6); a limit block (8) is provided in the groove (6) and is arranged corresponding to the central through hole of the chuck body; and a through groove is provided on the limit block (8) and is arranged opposite to the drill bit (101).

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