A replaceable blade-type large-diameter composite sheet hole-reaming drill bit

Abstract

The present invention relates to the technical field of reaming drill bits, and in particular to a replaceable blade-wing type large-diameter composite piece reaming drill bit, comprising a drill bit, a limit device, a positioning device and a protective device. The bottom end of the outer side of the drill bit is provided with a limit device, and the limit device is fixedly connected to the drill bit. The bottom end of the limit device is provided with a positioning device, and the top end of the outer side of the drill bit is provided with a protective device. In the present invention, a positioning block and a first blade are set. This setting cooperates with the spiral connection between the positioning block and the first screw, the sliding connection between the upper clamping block and the lower clamping block, and the spiral connection between the second screw and the first blade and the lower clamping block. When the device is used to reame a hole in a harder soil layer, the blade can be quickly replaced and installed after reaming. The operation is simple, convenient and quick.

Description

Technical Field

[0001] The invention relates to the technical field of reaming drill bits, in particular to a replaceable blade-wing type large-diameter composite sheet reaming drill bit. Background Art

[0002] The reaming drill bit is composed of a cutting edge and a chip groove. The cutting edge is used for drilling. The drill bit drills a bottom hole, and the reaming drill expands the bottom hole drilled by the drill bit. With the continuous development of society, the application of reaming drill bits is increasing, and the application fields of reaming drill bits are becoming more and more extensive. However, some composite sheet reaming drill bits have some defects when used. Therefore, the demand for a replaceable blade-wing large-diameter composite sheet reaming drill bit is growing.

[0003] In the field of reaming drill bits, some reaming drill bits currently in use are particularly inconvenient when replacing the blades. Since they are installed by welding, the replacement is time-consuming and labor-intensive, and the operation is difficult. In addition, when replacing the blades, it is not possible to ensure that the blades are installed evenly, which will reduce the service life of the blades and affect the normal use of the drill bit. Moreover, when some reaming drill bits are in use, when the device is subjected to a large torque, it is not possible to avoid the breakage of the drill bit connection inside the device. Once the device breaks, the drill bit cannot be removed, which not only reduces the service life of the drill bit, but also increases the cost investment. Therefore, a replaceable blade-wing large-diameter composite sheet reaming drill bit is proposed to address the above problems. Summary of the invention

[0004] The object of the present invention is to provide a replaceable blade-wing type large-diameter composite piece reaming drill bit to solve the problems raised in the above-mentioned background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A replaceable blade-type large-diameter composite sheet reaming drill bit comprises a drill bit, a limit device, a positioning device and a protective device. The bottom end of the outer side of the drill bit is provided with a limit device, and the limit device is fixedly connected to the drill bit. The bottom end of the limit device is provided with a positioning device, and the top end of the outer side of the drill bit is provided with a protective device.

[0007] Preferably, the limiting device includes a fixed disk, an adjusting block, a threaded shaft and a limiting block. A fixed disk is provided at the bottom outer side of the drill bit, and the fixed disk is fixedly connected to the drill bit. The fixed disk is slidably connected to the positioning device. An adjusting block is provided at the top of the fixed disk, and the adjusting block passes through the fixed disk. The adjusting block is rotatably connected to the fixed disk. A threaded shaft is fixedly connected to the bottom end surface of the adjusting block, and the threaded shaft is rotatably connected to the fixed disk. The outer side of the threaded shaft is spirally connected to the limiting block.

[0008] Preferably, the positioning device includes a positioning block, a first screw, an upper clamping block, a lower clamping block, a second screw, a first blade wing, a second blade wing, a wear-resistant layer and a third screw, the bottom end of the limiting device is slidably connected with the positioning block, the inner side of the positioning block is spirally connected with the first screw, and the first screw passes through the positioning block and the drill bit, the first screw is spirally connected to the drill bit, the outer side of the positioning block is fixedly connected with the upper clamping block, the inner side of the upper clamping block is slidably connected with the lower clamping block, the surface of the lower clamping block away from the center of the drill bit is slidably connected with the first blade wing, and the first blade wing is slidably connected to the limiting device, the surface of the lower clamping block close to the drill bit is spirally connected with the second screw, the second screw passes through the lower clamping block and the first blade wing, and the second screw is spirally connected to the first blade wing.

[0009] Preferably, a second blade wing is slidably connected to the surface of the lower clamping block away from the center of the drill bit, and the second blade wing is slidably connected to the limiting device, a second screw is spirally connected to the surface of the lower clamping block close to the drill bit, and the second screw penetrates the lower clamping block and the second blade wing, the second screw is spirally connected to the second blade wing, a wear-resistant layer is slidably connected to the outer side of the second blade wing, a third screw is spirally connected to the outer side of the wear-resistant layer, the third screw penetrates the wear-resistant layer and the second blade wing, and the third screw is spirally connected to the wear-resistant layer and the second blade wing.

[0010] Preferably, the protection device includes a fixed sleeve, a connecting block, a spring, a pressure sensor and an electric telescopic rod, the outer top end of the drill bit is rotatably connected to the fixed sleeve, the inner top end of the drill bit is slidably connected to the connecting block, and the connecting block passes through the drill bit and the fixed sleeve, the connecting block is slidably connected to the fixed sleeve, a spring is provided on the right side of the connecting block, the left side of the front end surface of the connecting block is slidably connected to the pressure sensor, and the pressure sensor is fixedly connected to the fixed sleeve, the left end surface of the connecting block is slidably connected to the electric telescopic rod, and the electric telescopic rod is fixedly connected to the fixed sleeve.

[0011] Preferably, the surface of the limit block close to the center of the fixed disk is arranged in an inclined surface, and the limit block is slidably connected to the fixed disk and the positioning device.

[0012] Preferably, the surface of the lower clamping block close to the center of the drill bit is arranged in an arc surface, and the lower clamping block is slidably connected to the drill bit.

[0013] Preferably, there are two springs, and the springs are symmetrically arranged on the right side of the connecting block, and the springs are fixedly connected to the connecting block and the drill bit.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] 1. In the present invention, by providing a positioning block and a first blade, this arrangement cooperates with the spiral connection between the positioning block and the first screw, the sliding connection between the upper clamping block and the lower clamping block, and the spiral connection between the second screw and the first blade and the lower clamping block. When the device is used to expand a hole in a harder soil layer, the blade can be quickly replaced and installed after the hole is expanded, and the operation is simple, convenient and fast.

[0016] 2. In the present invention, by providing a positioning block and a second blade, this arrangement cooperates with the spiral connection between the positioning block and the first screw, the sliding connection between the upper clamping block and the lower clamping block, and the spiral connection between the second screw and the second blade and the lower clamping block. When the device is used to expand a hole in a softer soil layer, the blade can be quickly replaced and installed after the hole is expanded. The operation is simple, convenient and fast, and the cost investment is reduced while ensuring normal hole expansion.

[0017] 3. In the present invention, by setting the limit block, the fixed connection between the adjusting block and the threaded shaft, the spiral connection between the threaded shaft and the limit block, and the sliding connection between the limit block and the fixed plate are coordinated, so that when the blade is replaced, the blade is limited to an equal spacing, thereby ensuring the service life of the blade and the normal use of the drill bit;

[0018] 4. In the present invention, by setting up a connecting block and a pressure sensor, this setting cooperates with the elastic force of the spring on the connecting block, the sliding connection between the connecting block and the fixing sleeve, the drill bit and the electric telescopic rod, and the pressure sensor to sense the pressure. When the device is subjected to a large torque during use, the phenomenon of breakage at the connection of the device is avoided, thereby ensuring the service life of the drill bit and reducing the cost investment. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the overall structure of the first embodiment of the present invention;

[0020] Figure 2 is a schematic diagram of the overall structure of the second embodiment of the present invention;

[0021] Figure 3 This is a schematic diagram of the installation structure of the upper clamping block of the present invention;

[0022] Figure 4 This is a schematic diagram of the installation structure of the limit block of the present invention;

[0023] Figure 5 This is a schematic diagram of the installation structure of the lower clamping block of the present invention;

[0024] Figure 6 It is a schematic diagram of the installation structure of the wear-resistant layer of the present invention.

[0025] In the figure: 1-drill bit, 2-limiting device, 201-fixed plate, 202-adjusting block, 203-threaded shaft, 204-limiting block, 3-positioning device, 301-positioning block, 302-first screw, 303-upper clamping block, 304-lower clamping block, 305-second screw, 306-first blade wing, 307-second blade wing, 308-wear-resistant layer, 309-third screw, 4-protective device, 401-fixing sleeve, 402-connecting block, 403-spring, 404-pressure sensor, 405-electric telescopic rod. DETAILED DESCRIPTION

[0026] Embodiment 1:

[0027] See also Figure 1 , Figure 3 , Figure 4 and Figure 5 , the present invention provides a technical solution:

[0028] A replaceable blade-type large-diameter composite sheet reaming drill bit comprises a drill bit 1, a limiting device 2, a positioning device 3 and a protective device 4. The limiting device 2 is provided at the outer bottom end of the drill bit 1, and the limiting device 2 is fixedly connected to the drill bit 1. The limiting device 2 comprises a fixed disk 201, an adjusting block 202, a threaded shaft 203 and a limiting block 204. The outer bottom end of the drill bit 1 is provided with a fixed disk 201, and the fixed disk 201 is fixedly connected to the drill bit 1. The fixed disk 201 is slidably connected to the positioning device 3. The top of the fixed disk 201 is provided with an adjusting block 202, and the adjusting block 202 penetrates the fixed disk 201, and the adjusting block 202 is rotatably connected to the fixed disk 201. The bottom end surface of the adjusting block 202 is fixedly connected to the threaded shaft 203, and the threaded shaft 203 is rotatably connected to the fixed disk 201. The outer side of the groove shaft 203 is spirally connected to the limiting block 204, and the surface of the limiting block 204 close to the center of the fixed disk 201 is set in an inclined surface, and the limiting block 204 is slidably connected to the fixed disk 201 and the positioning device 3. This arrangement avoids the collision between the limit block 204 and the fixed disk 201 when the blade is installed by limiting, and ensures the normal limiting installation of the blade. This arrangement realizes the limiting of the blade with equal spacing when the blade is replaced, thereby ensuring the service life of the blade and the normal use of the drill bit. A positioning device 3 is provided at the bottom end of the limiting device 2, and the positioning device 3 includes a positioning block 301, a first screw 302, an upper clamping block 303, a lower clamping block 304, a second screw 305, a first blade wing 306, a second blade wing 307, a wear-resistant layer 308 and a third screw 309. The bottom end of the positioning device 2 is slidably connected with a positioning block 301, and a first screw 302 is spirally connected to the inner side of the positioning block 301, and the first screw 302 penetrates the positioning block 301 and the drill bit 1, and the first screw 302 is spirally connected to the drill bit 1, and an upper clamping block 303 is fixedly connected to the outer side of the positioning block 301, and a lower clamping block 304 is slidably connected to the inner side of the upper clamping block 303, and the surface of the lower clamping block 304 close to the center of the drill bit 1 is arranged in an arc surface, and the lower clamping block 304 is slidably connected to the drill bit 1, and this arrangement ensures the stability of the blade after positioning, and a first blade wing 306 is slidably connected to the surface of the lower clamping block 304 away from the center of the drill bit 1, and the first blade wing 306 is slidably connected to the limiting device 2, and a second screw 305 is spirally connected to the surface of the lower clamping block 304 close to the drill bit 1, and the second screw 305 penetrates the lower clamping block 304 and the first blade wing 306, and the second screw 305 is spirally connected to the first blade wing 306. This arrangement realizes the rapid replacement and installation of the blade after the hole is expanded when the device is used to expand a harder soil layer. The operation is simple, convenient and fast. A protective device 4 is provided at the top of the outer side of the drill bit 1. The protective device 4 includes a fixed sleeve 401, a connecting block 402, a spring 403, a pressure sensor 404 and an electric telescopic rod 405. The top of the outer side of the drill bit 1 is rotatably connected with the fixed sleeve 401, and the top of the inner side of the drill bit 1 is slidably connected with the connecting block 402, and the connecting block 402 penetrates the drill bit 1 and the fixed sleeve 401, and the connecting block 402 is slidably connected to the fixed sleeve 401. A spring 403 is provided on the right side of the connecting block 402, and the spring 403 has 2.The spring 403 is symmetrically arranged on the right side of the connecting block 402, and the spring 403 is fixedly connected to the connecting block 402 and the drill bit 1. This arrangement realizes the automatic resetting of the connecting block 402 after the electric telescopic rod 405 is reset. The pressure sensor 404 is slidably connected to the left side of the front end surface of the connecting block 402, and the pressure sensor 404 is fixedly connected to the fixed sleeve 401. The electric telescopic rod 405 is slidably connected to the left end surface of the connecting block 402, and the electric telescopic rod 405 is fixedly connected to the fixed sleeve 401. This arrangement avoids the phenomenon of fracture at the connection of the device when it is subjected to a large torque during use, thereby ensuring the service life of the drill bit 1 and reducing the cost investment.

[0029] 306, and the upper and lower clamping blocks 303 are fixed to the middle position of the adjacent first blade wing 306, and the upper and lower clamping blocks 303 are fixed to the middle position of the adjacent first blade wing 306, and the upper and lower clamping blocks 303 are fixed to the middle position of the adjacent first blade wing 306, and the upper and lower clamping blocks 303 are fixed to the middle position of the adjacent first blade wing 306, and the upper and lower clamping blocks 304 ... adjacent first blade wing 306, and the upper and lower clamping blocks 303 are fixed to the adjacent first blade wing 306, and the upper and lower clamping blocks 303 are fixed to the adjacent first blade wing 306, and the upper and lower clamping blocks 303 are fixed to the adjacent first blade wing 306, and the upper and lower clamping blocks 303 are fixed to the adjacent first blade wing 306, and the upper and lower clamping blocks 303 are fixed to the adjacent first blade wing 306, and the upper and lower clamping blocks 303 are fixed to the adjacent first blade After that, the device is connected, and then the pressure range sensed by the pressure sensor 404 is set through the external control mechanism, and then the device can be used. During the rotation of the device, the connecting block 402 will continuously squeeze the pressure sensor 404. When the pressure value sensed by the pressure sensor 404 reaches the set range, the external control mechanism will control the electric telescopic rod 405 to fully extend. At this time, the connecting block 402 is just completely retracted into the drill bit 1, and the spring 403 is compressed at this time. Then the fixing sleeve 401 will continue to rotate with the drill bit 1. The pressure value sensed by the pressure sensor 404 at this time is zero, indicating that the device is subjected to a large torque at this time, which protects the device and avoids the breakage of the connection of the drill bit 1. When the first blade wing 306 needs to be replaced, it is only necessary to remove the first screw 302, and then rotate the adjusting block 202 counterclockwise to remove the first blade wing 306. The operation is simple and convenient, saving time and effort.

[0030] Embodiment 2:

[0031] See also Figure 2 , Figure 3 , Figure 4 and Figure 6 , the present invention provides a technical solution:

[0032] A replaceable blade-type large-diameter composite sheet reaming drill bit, comprising a drill bit 1, a limiting device 2, a positioning device 3 and a protective device 4, wherein the limiting device 2 is provided at the outer bottom end of the drill bit 1, and the limiting device 2 is fixedly connected to the drill bit 1, the limiting device 2 comprises a fixed disk 201, an adjusting block 202, a threaded shaft 203 and a limiting block 204, the outer bottom end of the drill bit 1 is provided with a fixed disk 201, and the fixed disk 201 is fixedly connected to the drill bit 1, the fixed disk 201 is slidably connected to the positioning device 3, the top of the fixed disk 201 is provided with an adjusting block 202, and the adjusting block 202 penetrates the fixed disk 201, the adjusting block 202 is rotatably connected to the fixed disk 201, the bottom end surface of the adjusting block 202 is fixedly connected to the threaded shaft 203, and the threaded shaft 203 is connected to the fixed disk 2 01 rotation connection, the outer side of the threaded shaft 203 is spirally connected to the limit block 204, the surface of the limit block 204 close to the center of the fixed disk 201 is set in an inclined surface, and the limit block 204 is slidably connected with the fixed disk 201 and the positioning device 3. This arrangement avoids the collision between the limit block 204 and the fixed disk 201 when the blade is installed by the limit, and ensures the normal limit installation of the blade. This arrangement realizes the limit of the blade with equal spacing when the blade is replaced, thereby ensuring the service life of the blade and the normal use of the drill bit. A positioning device 3 is provided at the bottom end of the limit device 2, and the positioning device 3 includes a positioning block 301, a first screw 302, an upper clamping block 303, a lower clamping block 304, a second screw 305, a first blade wing 306, a second blade wing 307, The wear-resistant layer 308 and the third screw 309, the bottom end of the limiting device 2 is slidably connected with a positioning block 301, the inner side of the positioning block 301 is spirally connected with a first screw 302, and the first screw 302 penetrates the positioning block 301 and the drill bit 1, the first screw 302 is spirally connected to the drill bit 1, the outer side of the positioning block 301 is fixedly connected with an upper clamping block 303, the inner side of the upper clamping block 303 is slidably connected with a lower clamping block 304, the surface of the lower clamping block 304 close to the center of the drill bit 1 is arranged in an arc surface, and the lower clamping block 304 is slidably connected to the drill bit 1, this arrangement ensures the stability of the blade after positioning, the surface of the lower clamping block 304 away from the center of the drill bit 1 is slidably connected with a second blade wing 307, and the second blade wing 307 is slidably connected to the limiting device 2, the lower clamping block 304 is close to the drill A second screw 305 is spirally connected to the surface of the head 1, and the second screw 305 penetrates the lower block 304 and the second blade wing 307, the second screw 305 is spirally connected to the second blade wing 307, the outer side of the second blade wing 307 is slidably connected to a wear-resistant layer 308, the outer side of the wear-resistant layer 308 is spirally connected to a third screw 309, and the third screw 309 penetrates the wear-resistant layer 308 and the second blade wing 307, the third screw 309 is spirally connected to the wear-resistant layer 308 and the second blade wing 307. This arrangement realizes the rapid replacement and installation of the blade after the hole is expanded when the device is used to expand the soft soil layer. The operation is simple, convenient and fast. While ensuring normal expansion, it also reduces the cost investment. A protective device 4 is provided on the top of the outer side of the drill bit 1.The protective device 4 includes a fixing sleeve 401, a connecting block 402, a spring 403, a pressure sensor 404 and an electric telescopic rod 405. The outer top of the drill bit 1 is rotatably connected to the fixing sleeve 401, and the inner top of the drill bit 1 is slidably connected to the connecting block 402, and the connecting block 402 passes through the drill bit 1 and the fixing sleeve 401. The connecting block 402 is slidably connected to the fixing sleeve 401. A spring 403 is provided on the right side of the connecting block 402. There are two springs 403, and the springs 403 are symmetrically arranged on the right side of the connecting block 402. The spring 403 is fixed to the connecting block 402 and the drill bit 1. This arrangement realizes the automatic resetting of the connection block 402 after the electric telescopic rod 405 is reset. The pressure sensor 404 is slidably connected to the left side of the front end surface of the connection block 402, and the pressure sensor 404 is fixedly connected to the fixed sleeve 401. The electric telescopic rod 405 is slidably connected to the left end surface of the connection block 402, and the electric telescopic rod 405 is fixedly connected to the fixed sleeve 401. This arrangement avoids the phenomenon of fracture at the connection of the device when it is subjected to a large torque during use, thereby ensuring the service life of the drill bit 1 and reducing the cost investment.

[0033] Working process: All electrical appliances in the device are externally powered. When the device is used to drill holes in a low-hardness ground, first fix the lower clamping block 304 and the second blade wing 307 together by the second screw 305, fix the wear-resistant layer 308 and the second blade wing 307 together by the third screw 309, and then clamp the second blade wing 307 at the bottom of the fixed plate 201 to ensure that the arc surface of the lower clamping block 304 is in contact with the drill bit 1, and then use a screwdriver to turn the adjustment block 202 clockwise. At this time, the threaded shaft 2 03 will rotate, and the limit block 204 will continue to slide downward, thereby continuously squeezing the second blade wing 307 through the inclined surface of the limit block 204. When the adjustment block 202 cannot continue to rotate, the second blade wing 307 completes the limit, and then the positioning block 301 fixed with the upper clamping block 303 is clamped in the middle position of the adjacent second blade wing 307 to ensure that the upper clamping block 303 and the lower clamping block 304 are clamped together. After completing the above operations, the positioning block 301 is fixed to the drill bit 1 through the first screw 302 After the drill bit 1 is assembled, the device is connected, and then the pressure range sensed by the pressure sensor 404 is set through the external control mechanism, and then the device can be used. During the rotation of the device, the connecting block 402 will continuously squeeze the pressure sensor 404. When the pressure value sensed by the pressure sensor 404 reaches the set range, the external control mechanism will control the electric telescopic rod 405 to fully extend. At this time, the connecting block 402 is just completely retracted into the drill bit 1, and the spring 403 is compressed at this time. Then the fixed sleeve 401 will continue to rotate with the drill bit 1. The pressure value sensed by the pressure sensor 404 at this time is zero, indicating that the device is subjected to a large torque at this time, which protects the device and avoids the phenomenon of breakage at the connection of the drill bit 1. When the wear-resistant layer 308 on the outer side of the second blade wing 307 needs to be replaced, it is only necessary to remove the third screw 309 to remove the wear-resistant layer 308. The operation is simple and convenient, saving time and effort, and reducing the cost investment while ensuring normal hole expansion.

[0034] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. The above is only a preferred implementation of the present invention. It should be pointed out that due to the limitations of textual expression and the objective existence of infinite specific structures, ordinary technicians in this technical field can make several improvements, modifications or changes without departing from the principles of the present invention, and can also combine the above technical features in an appropriate manner; these improvements, modifications, changes or combinations, or the direct application of the inventive concept and technical solution to other occasions without improvement, should be regarded as the protection scope of the present invention.

Claims

1. A replaceable blade-type large-diameter composite sheet reaming drill bit, comprising a drill bit (1), a limit device (2), a positioning device (3) and a protective device (4), characterized in that: A limiting device (2) is provided at the bottom end of the outer side of the drill bit (1), and the limiting device (2) is fixedly connected to the drill bit (1); a positioning device (3) is provided at the bottom end of the limiting device (2); and a protective device (4) is provided at the top end of the outer side of the drill bit (1); the limiting device (2) comprises a fixed disk (201), an adjusting block (202), a threaded shaft (203) and a limiting block (204); a fixing disk (201) is provided at the bottom end of the outer side of the drill bit (1), and the fixing disk (201) is fixedly connected to the drill bit (1); and the fixing disk (201) and the positioning device (3) are connected to the bottom end of the limiting device (2). The fixing plate (201) is slidably connected to the device (3); an adjusting block (202) is provided at the top of the fixing plate (201), and the adjusting block (202) penetrates the fixing plate (201); the adjusting block (202) is rotatably connected to the fixing plate (201); a threaded shaft (203) is fixedly connected to the bottom end surface of the adjusting block (202), and the threaded shaft (203) is rotatably connected to the fixing plate (201); the outer side of the threaded shaft (203) is spirally connected to a limiting block (204); the positioning device (3) comprises a positioning block (301), a first screw (302), an upper clamp The limiting device (2) comprises a positioning block (303), a lower clamping block (304), a second screw (305), a first blade wing (306), a second blade wing (307), a wear-resistant layer (308) and a third screw (309), wherein the bottom end of the limiting device (2) is slidably connected with a positioning block (301), the inner side of the positioning block (301) is spirally connected with a first screw (302), and the first screw (302) passes through the positioning block (301) and the drill bit (1), the first screw (302) is spirally connected with the drill bit (1), and the outer side of the positioning block (301) is fixedly connected with an upper clamping block (301). A block (303) is provided, wherein a lower block (304) is slidably connected to the inner side of the upper block (303), a first blade wing (306) is slidably connected to the surface of the lower block (304) away from the center of the drill bit (1), and the first blade wing (306) is slidably connected to the limiting device (2), a second screw (305) is spirally connected to the surface of the lower block (304) close to the drill bit (1), and the second screw (305) passes through the lower block (304) and the first blade wing (306), and the second screw (305) is spirally connected to the first blade wing (306).

2. The replaceable blade-type large-diameter composite sheet reaming drill bit according to claim 1, characterized in that: A second blade wing (307) is slidably connected to the surface of the lower clamping block (304) away from the center of the drill bit (1), and the second blade wing (307) is slidably connected to the limiting device (2); a second screw (305) is spirally connected to the surface of the lower clamping block (304) close to the drill bit (1), and the second screw (305) penetrates the lower clamping block (304) and the second blade wing (307); the second screw (305) is spirally connected to the second blade wing (307); a wear-resistant layer (308) is slidably connected to the outer side of the second blade wing (307); a third screw (309) is spirally connected to the outer side of the wear-resistant layer (308), and the third screw (309) penetrates the wear-resistant layer (308) and the second blade wing (307); the third screw (309) is spirally connected to the wear-resistant layer (308) and the second blade wing (307).

3. The replaceable blade-type large-diameter composite sheet reaming drill bit according to claim 1, characterized in that: The protection device (4) comprises a fixing sleeve (401), a connecting block (402), a spring (403), a pressure sensor (404) and an electric telescopic rod (405); the outer top end of the drill bit (1) is rotatably connected to the fixing sleeve (401); the inner top end of the drill bit (1) is slidably connected to the connecting block (402), and the connecting block (402) penetrates the drill bit (1) and the fixing sleeve (401); the connecting block (402) is slidably connected to the fixing sleeve (401); a spring (403) is provided on the right side of the connecting block (402); the left side of the front end surface of the connecting block (402) is slidably connected to the pressure sensor (404), and the pressure sensor (404) is fixedly connected to the fixing sleeve (401); the left end surface of the connecting block (402) is slidably connected to the electric telescopic rod (405), and the electric telescopic rod (405) is fixedly connected to the fixing sleeve (401).

4. The replaceable blade-type large-diameter composite sheet reaming drill bit according to claim 1, characterized in that: The surface of the limit block (204) close to the center of the fixed disk (201) is arranged in an inclined surface, and the limit block (204) is slidably connected to the fixed disk (201) and the positioning device (3).

5. The replaceable blade-type large-diameter composite sheet reaming drill bit according to claim 1, characterized in that: The surface of the lower clamping block (304) close to the center of the drill bit (1) is arranged in the form of an arc surface, and the lower clamping block (304) is slidably connected to the drill bit (1).

6. The replaceable blade-type large-diameter composite sheet reaming drill bit according to claim 3, characterized in that: There are two springs (403), and the springs (403) are symmetrically arranged on the right side of the connecting block (402). The springs (403) are fixedly connected to the connecting block (402) and the drill bit (1).

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