CN219763465U - Milling mobile phone capable of preventing cutter from breaking - Google Patents

Abstract

The utility model discloses a milling mobile phone capable of preventing a cutter from being broken, wherein the milling mobile phone comprises: a handle body provided with a receiving channel; the main shaft assembly is arranged in the accommodating channel; the bearing is provided with an inner ring and an outer ring, the inner ring is sleeved outside the main shaft assembly, and the outer ring is abutted against the inner wall of the accommodating channel; one end of the limiting piece is in butt joint with the outer ring, and the other end of the limiting piece extends in a direction away from the bearing; and the locating piece is connected with one end, far away from the bearing, of the limiting piece and the handle body so as to limit the limiting piece to rotate around the axial direction of the spindle assembly. The technical scheme of the utility model solves the problem that the milling cutter driven by the milling mobile phone is easy to break.

Description

Milling handpiece to prevent tool breakage

Technical field

The utility model relates to the technical field of surgical instruments, in particular to a milling handpiece that prevents knife breakage.

Background technique

In neurosurgery, it is sometimes necessary to use a medical milling device to mill the skull. The medical milling device includes a milling handpiece and a milling cutter driven by it. The milling cutter rotates at high speed to cut the skull.

Existing milling handpieces generally include a handle body, a spindle connected to the handle body through bearings, a shoe rod barrel with one end fixedly connected to the spindle in the axial direction, and a guard shoe detachably fixedly connected to the shoe rod barrel. One end of the milling cutter is inserted into the handle body. The other end of the main shaft is dynamically matched with the boot foot of the protective boot. The outer ring of the bearing limits the axial movement of the bearing through a stopper, which is inside the handle body and is threadedly connected to the inner wall of the handle body.

However, when this kind of milling handpiece is running at high speed, the rotation of the spindle may loosen the threaded connection between the stopper and the inner wall of the handle, causing the bearing and spindle to move in the axial direction, causing the milling cutter connected to the spindle to easily break. question.

Utility model content

The main purpose of the utility model is to provide a milling handpiece that prevents cutter breakage, aiming to solve the problem that the milling cutter driven by the milling handpiece is easy to break.

In order to achieve the above purpose, the utility model proposes a milling handpiece that prevents cutter breakage, including:

The handle body is provided with a receiving channel;

A spindle assembly located inside the accommodation channel;

Bearing, the bearing has an inner ring and an outer ring, the inner ring is sleeved on the outside of the main shaft assembly, and the outer ring is in contact with the inner wall of the receiving channel;

A stopper, one end of the stopper is in contact with the outer ring, and the other end of the stopper extends in a direction away from the bearing;

A positioning member connects an end of the limiting member away from the bearing and the handle body.

Optionally, the limiting member includes:

A support portion is sleeved on the outside of the spindle assembly, one end of the support portion abuts the outer ring, and the other end of the support portion extends in a direction away from the bearing;

A positioning part is provided on the outer periphery of the support part. The inner wall of the receiving channel is provided with a ladder structure corresponding to the positioning part. The positioning part is provided with a positioning hole. The positioning piece passes through the positioning hole and the positioning part. Ladder structure screw connection.

Optionally, the positioning hole includes a first sub-hole and a second sub-hole that are connected, and the second sub-hole is provided on a side of the first sub-hole away from the ladder structure. The diameter of the hole is larger than the diameter of the first sub-hole.

Optionally, the milling handpiece also includes:

An end stopper, fixed to one end of the handle body away from the positioning member;

The lock sleeve is sleeved on the handle body and the end stop, and is threadedly connected to the outer periphery of the handle body. The handle body, the end stop and the lock sleeve together form a receiving cavity. The axial movement of the lock sleeve along the handle body makes the volume of the receiving cavity adjustable;

The blocking member is located inside the receiving cavity and sleeved on the handle body.

Optionally, the lock sleeve has an adjacent first side wall and a second side wall, the end stop has an adjacent third side wall and a fourth side wall, the first side wall, the The second side wall, the fourth side wall and the handle body together form the receiving cavity, the first side wall is in contact with the third side wall, and the second side wall is in contact with the third side wall. The four side walls are arranged oppositely, and the movement of the lock sleeve causes the second side wall to approach or move away from the fourth side wall. The blocking member has an arc-shaped wall, and the blocking member resists the arc-shaped wall through the arc-shaped wall. Connecting the second side wall and the fourth side wall.

Optionally, the barrier is in the shape of a ring with an opening.

Optionally, the barrier is a wire retaining ring for holes.

Optionally, the first side wall is provided with a first installation groove corresponding to the barrier member, the first installation groove is recessed in a direction away from the receiving cavity, and the barrier member is partially provided on the first installation groove. inside the tank.

Optionally, the spindle assembly includes:

A connecting shaft, the first end of which is used to connect the driving member;

A sleeve, set on the second end of the connecting shaft;

A connecting pin connects the sleeve and the second end of the connecting shaft. The inner ring of the bearing is sleeved on the outside of the sleeve and covers the connecting pin.

Optionally, a second installation groove is provided on the outer periphery of the sleeve, and a retaining ring is provided in the second installation groove. The retaining ring abuts the inner ring to limit the axial movement of the bearing.

A milling handpiece in a technical solution of an embodiment of the present invention includes a handle body, a spindle assembly, a bearing, a limiting member and a positioning member. The spindle assembly is used to connect the driving member and the milling cutter. The inner ring of the bearing is set on the outside of the spindle assembly. , the peripheral surface of the outer ring of the bearing is in contact with the inner wall of the receiving channel, thereby ensuring that the spindle assembly rotates well in the receiving channel. One end of the limiting member is in contact with the side wall of the outer ring of the bearing, and the other end of the limiting member is fixed to the inner wall of the receiving channel through the positioning member, thereby limiting the axial movement of the bearing. The limiting piece fits the inner wall of the receiving channel, and there is no threaded connection between the limiting piece and the inner wall of the receiving channel, which can improve the coaxiality of the limiting piece and the handle body, reduce vibration during the operation of the milling handpiece, and at the same time reduce The processing difficulty of the stopper and handle body. There is no threaded connection between the limiter and the handle body, so the connection with the handle body will not become loose due to the rotation of the spindle assembly. The positioning piece can directly penetrate the limiter and the handle body and be fixed by screwing or welding. , the connection strength of the positioning piece is basically not affected by the rotation of the spindle assembly, making it difficult for the bearing and spindle assembly to move in the axial direction, thereby reducing the possibility of the milling cutter breaking.

Description of the drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description These are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on the structures shown in these drawings without exerting creative efforts.

Figure 1 is a partial cross-sectional view of an embodiment of a milling handpiece that prevents cutter breakage according to the present invention;

Figure 2 is a partial enlarged view of point A in Figure 1;

Figure 3 is a partial cross-sectional view 2 of an embodiment of a milling handpiece that prevents cutter breakage according to the present invention;

Figure 4 is a partial enlarged view of B in Figure 3;

Figure 5 is a partial cross-sectional view 3 of an embodiment of a milling handpiece that prevents cutter breakage according to the present invention;

Figure 6 is a partial enlarged view of position C in Figure 5.

Explanation of reference numbers:

The realization of the purpose, functional features and advantages of the present utility model will be further described with reference to the embodiments and the accompanying drawings.

Detailed ways

The technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only some of the embodiments of the present utility model, not all of them. Example. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present utility model.

It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present invention are only used to explain the relationship between various components in a specific posture (as shown in the accompanying drawings). The relative position relationship, movement conditions, etc., if the specific posture changes, the directional indication will also change accordingly.

In this utility model, unless otherwise expressly stipulated and limited, the terms "connection" and "fixing" should be understood in a broad sense. For example, "fixing" can be a fixed connection, a detachable connection, or an integral body; It can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be an internal connection between two elements or an interactive relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as instructions or instructions. implying its relative importance or implicitly specifying the quantity of the technical feature indicated. Therefore, features defined as "first" and "second" may explicitly or implicitly include at least one of these features. In addition, the meaning of "and/or" appearing in the entire text includes three parallel solutions. Taking "A and/or B" as an example, it includes solution A, or solution B, or a solution that satisfies both A and B at the same time. In addition, the technical solutions in various embodiments can be combined with each other, but it must be based on the realization by those of ordinary skill in the art. When the combination of technical solutions is contradictory or cannot be realized, it should be considered that such a combination of technical solutions does not exist. , nor is it within the protection scope required by this utility model.

Existing milling handpieces generally include a handle body, a spindle connected to the handle body through bearings, a shoe rod barrel with one end fixedly connected to the spindle in the axial direction, and a guard shoe detachably fixedly connected to the shoe rod barrel. One end of the milling cutter is inserted into the handle body. The other end of the main shaft is dynamically matched with the foot of the boot. The outer ring of the bearing limits the axial movement of the bearing through a stopper, which is inside the handle body and is threadedly connected to the inner wall of the handle body. When the milling handpiece is working, the motor drives the spindle to rotate at high speed. Due to the threaded connection between the stopper and the inner wall of the handle body, regardless of whether the rotation direction of the threaded connection is the same as or opposite to the rotation direction of the spindle, the stopper may be caused when the spindle rotates. The threaded connection with the inner wall of the handle is loose, so that the stopper cannot limit the axial movement of the bearing, causing the bearing and spindle to move in the axial direction, which in turn causes the connection between the milling cutter and the spindle to loosen and break the cutter. There is a large medical risk. Risk of accidents.

The utility model proposes a milling handpiece that prevents cutter breakage.

Please refer to Figures 1 and 3. Figure 1 is a partial cross-sectional view of an embodiment of a milling handpiece that prevents cutter breakage according to the present invention. Figure 3 is a partial cross-sectional view of an embodiment of a milling handpiece that prevents cutter breakage according to the present invention.

In the embodiment of the present invention, the milling handpiece that prevents tool breakage includes:

The handle body 100 is provided with a receiving channel;

The spindle assembly 200 is located inside the receiving channel;

Bearing 300. The bearing 300 has an inner ring 310 and an outer ring 320. The inner ring 310 is sleeved on the outside of the spindle assembly 200, and the outer ring 320 is in contact with the inner wall of the receiving channel;

Limiting member 400, one end of the limiting member 400 is in contact with the outer ring 320, and the other end of the limiting member 400 extends in a direction away from the bearing 300;

The positioning member 500 connects the end of the limiting member 400 away from the bearing 300 and the handle body 100 .

The milling handpiece in a technical solution of the embodiment of the present invention includes a handle body 100, a spindle assembly 200, a bearing 300, a limiting member 400 and a positioning member 500. The spindle assembly 200 is used to connect the driving member and the milling cutter. The inner part of the bearing 300 The ring 310 is sleeved on the outside of the main shaft assembly 200, and the peripheral surface of the outer ring 320 of the bearing 300 is in contact with the inner wall of the receiving channel, thereby ensuring that the main shaft assembly 200 rotates well in the receiving channel. One end of the limiting member 400 is in contact with the side wall of the outer ring 320 of the bearing 300, and the other end of the limiting member 400 is fixed to the inner wall of the receiving channel through the positioning member 500, thereby limiting the axial movement of the bearing 300. The limiter 400 fits the inner wall of the accommodation channel, and there is no threaded connection between the limiter 400 and the inner wall of the accommodation channel, which can improve the coaxiality between the limiter 400 and the handle body 100, reduce vibration during the operation of the milling handpiece, and at the same time The processing difficulty of the limiting member 400 and the handle body 100 can also be reduced. There is no threaded connection between the limiter 400 and the handle body 100, so the connection with the handle body 100 will not be loose due to the rotation of the spindle assembly 200. The positioner 500 can directly penetrate the limiter 400 and the handle body 100, and pass through Fixed by screwing or welding, the connection strength of the positioning member 500 is basically not affected by the rotation of the spindle assembly 200, making it difficult for the bearing 300 and the spindle assembly 200 to move in the axial direction, thus reducing the possibility of the milling cutter breaking.

Optionally, the limiting member 400 includes:

The support part 410 is sleeved on the outside of the spindle assembly 200. One end of the support part 410 contacts the outer ring 320, and the other end of the support part 410 extends in a direction away from the bearing 300;

The positioning part 420 is provided on the outer periphery of the support part 410. The inner wall of the receiving channel is provided with a ladder structure corresponding to the positioning part 420. The positioning part 420 is provided with a positioning hole 421. The positioning member 500 passes through the positioning hole 421 and is screwed to the ladder structure.

Please refer to Figure 4. In this embodiment, the limiter 400 includes a support part 410 and a positioning part 420. The support part 410 fits the inner wall of the receiving channel and mainly functions to limit the movement of the bearing 300. The positioning part 420 is provided on the support part. The outer periphery of 410 is used to connect with the handle body 100. In order to facilitate the use of the user, the milling handpiece needs to have a certain length, which makes the spindle assembly 200 longer. In order to ensure the rotation of the spindle assembly 200, the bearing 300 needs to be set at a relatively middle position of the spindle assembly 200. Therefore, the support part 410 and the positioning part 410 are provided. The portion 420 can not only facilitate the positioning of the bearing 300, but also facilitate the fixing of the limiting member 400 itself. The inner wall of the receiving channel is provided with a ladder structure corresponding to the positioning part 420. The positioning part 420 is provided with a positioning hole 421 corresponding to the positioning member 500. The positioning member 500 passes through the positioning hole 421 and is screwed to the ladder structure. The structure is simple and the processing is easy.

Optionally, the positioning hole 421 includes a first sub-hole 4211 and a second sub-hole 4212 that are connected. The second sub-hole 4212 is provided on the side of the first sub-hole 4211 away from the stepped structure. The diameter of the second sub-hole 4212 is larger than The diameter of the first sub-hole 4211.

Please refer to Figure 4. In this embodiment, the positioning hole 421 includes a first sub-hole 4211 and a second sub-hole 4212. The first sub-hole 4211 is provided on the side of the positioning portion 420 facing the ladder structure. The diameter of the second sub-hole 4212 is is larger than the diameter of the first sub-hole 4211. Specifically in this embodiment, the positioning member 500 is a countersunk head screw, and the second sub-hole 4212 can hide the head of the countersunk head screw. On the one hand, it improves the aesthetics of the milling handpiece, and on the other hand, it prevents the exposed screw head from being scratched. harm the user. There are multiple positioning holes 421 in a circumferential array, and a positioning member 500 is provided corresponding to each positioning hole 421, which can improve the connection strength between the limiting member 400 and the handle body 100, and further reduce the possibility of the knife breaking.

Optionally, the milling handpiece also includes:

The end stop 600 is fixed to the end of the handle body 100 away from the positioning member 500;

The lock sleeve 700 is sleeved on the handle body 100 and the end stop 600 and is threadedly connected to the outer periphery of the handle body 100. The handle body 100, the end stop 600 and the lock sleeve 700 together form a receiving cavity. The lock sleeve 700 extends along the handle The axial movement of the body 100 makes the volume of the receiving cavity adjustable;

The blocking member 800 is located inside the receiving cavity and sleeved on the handle body 100 .

Please combine Figure 2, Figure 5 and Figure 6. In this embodiment, the milling handpiece also includes an end stop 600, a lock sleeve 700 and a barrier 800. Through the threaded connection between the lock sleeve 700 and the handle body 100, the lock sleeve 700 can move along the axial direction of the handle body 100. The lock sleeve 700 moves in the direction away from the end stop 600, so that the milling cutter and the spindle assembly 200 can be locked. The lock sleeve 700 moves in the direction close to the end stop 600. The milling cutter can be separated from the spindle assembly 200 . The end stop 600 is used to prevent the lock sleeve 700 from being separated from the handle body 100. Specifically in this embodiment, the end stop 600 is a nut, which is screwed to one end of the handle body 100, and is connected to the handle body by welding or bonding. 100 is fixed to prevent the spindle assembly 200 from rotating, causing the nut to loosen and fall off, and thus unable to prevent the lock sleeve 700 from being separated from the handle body 100. When it is necessary to separate the milling cutter from the spindle assembly 200, the user twists the lock sleeve 700 and moves it toward the end stop 600. In order to facilitate manual twisting, the lock sleeve 700 has a large friction coefficient due to its material. When the lock sleeve 700 and the end stop 600 are in close contact, it is easy to cause a large static friction force between the lock sleeve 700 and the end stop 600. When the lock sleeve 700 is twisted in the direction away from the end stop 600, it will be more laborious or even stuck. Dead question. The barrier member 800 is sleeved on the handle body 100 and is arranged between the lock sleeve 700 and the end stop 600 to isolate the lock sleeve 700 and the end stop 600. The friction coefficient between the barrier member 800 and the lock sleeve 700 and The friction coefficient between the barrier member 800 and the end stopper 600 is small, so that it is difficult to get stuck between the barrier member 800 and the lock sleeve 700, and at the same time, it is difficult to get stuck between the barrier member 800 and the end stopper 600, thereby reducing the lock. The possibility of sleeve 700 getting stuck near end stop 600.

Optionally, the lock sleeve 700 has adjacent first side walls 710 and second side walls 720, the end stop 600 has adjacent third side walls 610 and fourth side walls 620, the first side wall 710, the The two side walls 720 , the fourth side wall 620 and the handle body 100 together form a receiving cavity. The first side wall 710 is in contact with the third side wall 610 . The second side wall 720 and the fourth side wall 620 are arranged oppositely. The movement of the sleeve 700 causes the second side wall 720 to approach or move away from the fourth side wall 620. The barrier member 800 has an arc-shaped wall, and the barrier member 800 abuts the second side wall 720 and the fourth side wall 620 through the arc-shaped wall.

Please refer to Figure 2. In this embodiment, the lock sleeve 700 has adjacent first side walls 710 and second side walls 720, and the end stop 600 has adjacent third side walls 610 and fourth side walls 620. The one side wall 710, the second side wall 720, the fourth side wall 620 and the handle body 100 together form a receiving cavity, so that the lock sleeve 700 can also play a certain protective role. During the process of milling the mobile phone or cleaning and disinfecting, The possibility of liquid entering the inside of the milling handpiece between the self-locking sleeve 700 and the handle body 100 is reduced. The adjacent third side wall 610 and the fourth side wall 620 of the end stop 600 form an edge. When the lock sleeve 700 drives the barrier 800 to contact the end stop 600, the end stop 600 contacts the barrier 800 through the edges. The arc-shaped wall makes the direction of force transmission between the barrier 800 and the end stop 600 inclined to the axial direction of the lock sleeve 700, that is, the positive pressure between the barrier 800 and the end stop 600 is reduced, thereby reducing The static friction force between the blocking member 800 and the end blocking member 600 is reduced, so that the blocking problem between the blocking member 800 and the end blocking member 600 is less likely to occur.

Optionally, the barrier 800 is in the shape of a ring with an opening.

In this embodiment, the blocking member 800 is in the shape of a ring with an opening. When the milling handpiece is subjected to high-temperature sterilization, the milling cutter is generally separated from the spindle assembly 200, that is, the lock sleeve 700 will most likely be located close to the end stop 600. That is, the lock sleeve 700 is in a state of contacting the barrier member 800 and the barrier member 800 is in contact with the end stopper 600. The high temperature will cause the lock sleeve 700, the handle body 100, the end stopper 600, etc. to expand slightly in volume. 700, the barrier 800 and the end stop 600 will squeeze each other, which will increase the positive pressure between the lock sleeve 700 and the barrier 800 and between the barrier 800 and the end stop 600, causing the lock sleeve 700 to easily appear. The blocking member 800 is in the shape of a ring with an opening, so that the receiving cavity is not completely closed, leaving space for the volume expansion of the lock sleeve 700, the blocking member 800 and the end stop 600, so that the lock sleeve 700 and the blocking member 800 are And the space between the end stops 600 is less affected by high temperature, which reduces the possibility of the lock sleeve 700 getting stuck.

Optionally, the barrier 800 is a hole wire retaining ring 900 .

In this embodiment, the barrier 800 is a hole steel wire retaining ring 900. The hole steel wire retaining ring 900 isolates the end face of the lock sleeve 700 from the end face of the end stop 600, thereby reducing the distance between the lock sleeve 700 and the end stop when screwing. The possibility of the component 600 being stuck due to tight contact is eliminated. The wire retaining ring 900 for the hole is easy to select, easy to purchase and low in price.

Optionally, the first side wall 710 is provided with a first installation groove 711 corresponding to the barrier member 800. The first installation groove 711 is recessed in a direction away from the receiving cavity, and the barrier member 800 is partially disposed inside the first installation groove 711.

Please refer to Figure 2. In this embodiment, the first side wall 710 is provided with a first installation groove 711 corresponding to the barrier member 800. The barrier member 800 is disposed in the first installation groove 711. On the one hand, it is convenient to limit the barrier member 800. On the other hand, it is easy to process.

Optionally, spindle assembly 200 includes:

Connecting shaft 210, the first end of the connecting shaft 210 is used to connect the driving member;

The sleeve 220 is sleeved on the second end of the connecting shaft 210;

The connecting pin 230 connects the sleeve 220 and the second end of the connecting shaft 210 . The inner ring 310 of the bearing 300 is sleeved on the outside of the sleeve 220 and covers the connecting pin 230 .

Please refer to Figure 2. In this embodiment, the spindle assembly 200 includes a connecting shaft 210, a sleeve 220 and a connecting pin 230. The first end of the connecting shaft 210 is connected to a driving component, which can be a motor or a reducer, etc., and the third end of the connecting shaft 210 is connected to a driving component. The two ends are connected to the sleeve 220. If the spindle size of the milling handpiece is too long, it will easily lead to problems such as difficulty in processing and difficulty in ensuring coaxiality. By connecting the shaft 210 and the sleeve 220 in two sections, the difficulty of processing can be reduced and the manufacturing accuracy can be improved. This ensures that the spindle assembly 200 can stably rotate at high speed, further reducing the possibility of tool breakage. One end of the sleeve 220 is sleeved on the second end of the connecting shaft 210, and the other end of the sleeve 220 is used to fix the milling cutter. The connecting pin 230 passes through the connecting shaft 210 and the sleeve 220, thereby realizing the connection between the sleeve 220 and the connecting shaft 210. Fixed, simple structure, easy to assemble and disassemble. The inner ring 310 of the bearing 300 is sleeved on the outside of the sleeve 220 and covers the connecting pin 230, which can prevent the connecting pin 230 from coming out during high-speed operation.

Optionally, a second installation groove is provided on the outer periphery of the sleeve 220 , and a retaining ring 900 is provided in the second installation groove. The retaining ring 900 abuts the inner ring 310 to limit the axial movement of the bearing 300 .

Please refer to Figure 2. In this embodiment, the axial movement of the inner ring 310 of the bearing 300 is limited by a retaining ring 900. A second installation groove is provided on the outer periphery of the sleeve 220 corresponding to the retaining ring 900. A part of the retaining ring 900 is located on the second mounting groove. In the installation groove, another part of the retaining ring 900 extends out of the second installation groove to abut the side wall of the inner ring 310 of the bearing 300, thereby limiting the position of the bearing 300. The structure is simple and easy to disassemble and assemble.

The above are only optional embodiments of the present utility model, and do not limit the patent scope of the present utility model. Under the inventive concept of the present utility model, equivalent structural transformations can be made by using the contents of the description and drawings of the present utility model. Or directly/indirectly used in other related technical fields are included in the scope of patent protection of this utility model.

Claims (10)

1. A milling handpiece that prevents tool breakage, which is characterized by including: The handle body is provided with a receiving channel; A spindle assembly located inside the accommodation channel; Bearing, the bearing has an inner ring and an outer ring, the inner ring is sleeved on the outside of the main shaft assembly, and the outer ring is in contact with the inner wall of the receiving channel; A stopper, one end of the stopper is in contact with the outer ring, and the other end of the stopper extends in a direction away from the bearing; A positioning member connects an end of the limiting member away from the bearing and the handle body. 2. The milling handpiece for preventing cutter breakage according to claim 1, wherein the limiting member includes: A support portion is sleeved on the outside of the spindle assembly, one end of the support portion abuts the outer ring, and the other end of the support portion extends in a direction away from the bearing; A positioning part is provided on the outer periphery of the support part. The inner wall of the receiving channel is provided with a ladder structure corresponding to the positioning part. The positioning part is provided with a positioning hole. The positioning piece passes through the positioning hole and the positioning part. Ladder structure screw connection. 3. The milling handpiece for preventing cutter breakage according to claim 2, wherein the positioning hole includes a first sub-hole and a second sub-hole that are connected, and the second sub-hole is provided on the first sub-hole. The side of the sub-hole is away from the step structure, and the diameter of the second sub-hole is larger than the diameter of the first sub-hole. 4. The milling handpiece for preventing cutter breakage according to claim 1, characterized in that the milling handpiece further includes: An end stopper, fixed to an end of the handle body away from the positioning member; The lock sleeve is sleeved on the handle body and the end stop, and is threadedly connected to the outer periphery of the handle body. The handle body, the end stop and the lock sleeve together form a receiving cavity. The axial movement of the lock sleeve along the handle body makes the volume of the receiving cavity adjustable; The blocking member is located inside the receiving cavity and sleeved on the handle body. 5. The milling handpiece for preventing cutter breakage according to claim 4, wherein the lock sleeve has an adjacent first side wall and a second side wall, and the end stop has an adjacent third side wall. The first side wall, the second side wall, the fourth side wall and the handle body together form the receiving cavity, and the first side wall and the third side wall Three side walls are in contact with each other, the second side wall is opposite to the fourth side wall, and the movement of the lock sleeve causes the second side wall to approach or move away from the fourth side wall, and the barrier member It has an arc-shaped wall, and the barrier member abuts the second side wall and the fourth side wall through the arc-shaped wall. 6. The milling handpiece for preventing cutter breakage according to claim 5, wherein the blocking member is in the shape of a ring with an opening. 7. The milling handpiece for preventing cutter breakage according to claim 6, wherein the blocking member is a wire retaining ring for holes. 8. The milling handpiece to prevent tool breakage according to claim 5, wherein the first side wall is provided with a first installation groove corresponding to the barrier member, and the first installation groove faces away from the receiving cavity. The direction of the barrier is recessed, and the barrier member is partially disposed inside the first installation groove. 9. The milling handpiece that prevents tool breakage according to claim 1, wherein the spindle assembly includes: A connecting shaft, the first end of which is used to connect the driving member; A sleeve, set on the second end of the connecting shaft; A connecting pin connects the sleeve and the second end of the connecting shaft. The inner ring of the bearing is sleeved on the outside of the sleeve and covers the connecting pin. 10. The milling handpiece for preventing cutter breakage according to claim 9, wherein a second installation groove is provided on the outer periphery of the sleeve, and a retaining ring is provided in the second installation groove, and the retaining ring resists The inner ring is connected to limit the axial movement of the bearing.