CN219763465U

CN219763465U - Milling mobile phone capable of preventing cutter from breaking

Info

Publication number: CN219763465U
Application number: CN202321007298.XU
Authority: CN
Inventors: 郭毅军; 陈亚洁; 唐杰
Original assignee: Chongqing Xishan Science and Technology Co Ltd
Current assignee: Chongqing Xishan Science and Technology Co Ltd
Priority date: 2023-04-27
Filing date: 2023-04-27
Publication date: 2023-09-29
Anticipated expiration: 2033-04-27

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 mobile phone capable of preventing cutter from breaking

Technical Field

The utility model relates to the technical field of surgical instruments, in particular to a milling hand machine capable of preventing a cutter from being broken.

Background

In neurosurgery, it is sometimes necessary to mill the skull bone with a medical milling device, which includes a milling handpiece and a milling cutter driven thereby, the milling cutter being rotated at a high speed to cut the skull bone.

The existing milling hand machine generally comprises a handle body, a main shaft, a boot rod barrel and a boot, wherein the main shaft is connected in the handle body in a matched mode through a bearing, one end of the boot rod barrel is fixedly connected with the main shaft in the axial direction, the boot is detachably and fixedly connected with the boot rod barrel, one end of a milling cutter is inserted into the main shaft, and the other end of the milling cutter is in movable fit with a boot foot of the boot. The outer ring of the bearing limits the axial movement of the bearing through a limiting piece, and the limiting piece is arranged in the handle body and is in threaded connection with the inner wall of the handle body.

However, when the milling mobile phone runs at a high speed, the rotation of the main shaft can loosen the threaded connection between the limiting piece and the inner wall of the handle body, so that the bearing and the main shaft can move along the axial direction, and further the problem that a milling cutter connected with the main shaft is easy to break is caused.

Disclosure of Invention

The utility model mainly aims to provide a milling mobile phone capable of preventing a cutter from being broken, and aims to solve the problem that a milling cutter driven by the milling mobile phone is easy to break.

In order to achieve the above object, the present utility model provides a milling machine capable of preventing a cutter from breaking, comprising:

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.

Optionally, the limiting member includes:

the support part is sleeved outside the main shaft assembly, one end of the support part is abutted against the outer ring, and the other end of the support part extends in a direction away from the bearing;

the positioning part is arranged on the periphery of the supporting part, a step structure is arranged on the inner wall of the accommodating channel corresponding to the positioning part, a positioning hole is formed in the positioning part, and the positioning piece passes through the positioning hole and is in threaded connection with the step structure.

Optionally, the positioning hole includes a first sub-hole and a second sub-hole that are communicated, the second sub-hole is disposed on a side of the first sub-hole that faces away from the stepped structure, and a diameter of the second sub-hole is greater than a diameter of the first sub-hole.

Optionally, the milling machine further includes:

the end baffle piece is fixed at one end of the handle body far away from the positioning piece;

the lock sleeve is sleeved on the handle body and the end baffle piece and is in threaded connection with the periphery of the handle body, the end baffle piece and the lock sleeve jointly encircle to form a containing cavity, and the volume of the containing cavity is adjustable due to the axial movement of the lock sleeve along the handle body;

the blocking piece is arranged in the accommodating cavity and sleeved on the handle body.

Optionally, the lock sleeve has adjacent first lateral wall and second lateral wall, the end keeps off the piece and has adjacent third lateral wall and fourth lateral wall, first lateral wall the second lateral wall the fourth lateral wall and the handle body surrounds jointly and forms the chamber of acceping, first lateral wall with third lateral wall butt, the second lateral wall with fourth lateral wall sets up relatively, through the motion of lock sleeve makes the second lateral wall is close to or keeps away from the fourth lateral wall, the separation member has the arc wall, the separation member passes through the arc wall butt second lateral wall with fourth lateral wall.

Optionally, the barrier is annular with an opening.

Optionally, the blocking member is a steel wire retainer ring for holes.

Optionally, the first side wall is provided with a first mounting groove corresponding to the blocking member, the first mounting groove is recessed in a direction away from the accommodating cavity, and the blocking member is partially arranged inside the first mounting groove.

Optionally, the spindle assembly includes:

the first end of the connecting shaft is used for connecting the driving piece;

the sleeve is sleeved at the second end of the connecting shaft;

the connecting pin is connected with the sleeve and the second end of the connecting shaft, and the inner ring of the bearing is sleeved outside the sleeve and covers the connecting pin.

Optionally, a second mounting groove is formed in the outer periphery of the sleeve, and a retainer ring is arranged in the second mounting groove and abuts against the inner ring to limit axial movement of the bearing.

The milling mobile phone in one technical scheme of the embodiment of the utility model comprises a handle body, a main shaft assembly, a bearing, a limiting piece and a positioning piece, wherein the main shaft assembly is used for connecting a driving piece and a milling cutter, an inner ring of the bearing is sleeved outside the main shaft assembly, and the peripheral surface of an outer ring of the bearing is abutted with the inner wall of a containing channel, so that the main shaft assembly is guaranteed to rotate well in the containing channel. One end of the limiting piece is abutted against the side wall of the outer ring of the bearing, and the other end of the limiting piece is fixed on the inner wall of the accommodating channel through the positioning piece, so that the bearing is limited to move in the axial direction. The limiting piece is attached to the inner wall of the accommodating channel, no threaded connection is arranged between the limiting piece and the inner wall of the accommodating channel, coaxiality of the limiting piece and the handle body can be improved, vibration in the work of the milling mobile phone is reduced, and meanwhile machining difficulty of the limiting piece and the handle body can be reduced. The locating piece is fixed in a threaded or welded mode, the connecting strength of the locating piece is not influenced by rotation of the main shaft assembly basically, so that the bearing and the main shaft assembly are difficult to move in the axial direction, and the possibility of cutter breakage of the milling cutter is reduced.

Drawings

In order to more clearly illustrate the embodiments of the present utility model or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, and it is obvious that the drawings in the following description are only some embodiments of the present utility model, and other drawings may be obtained according to the structures shown in these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a partial cross-sectional view of one embodiment of a milling cutter head for preventing breakage in accordance with the present utility model;

FIG. 2 is an enlarged view of a portion of FIG. 1 at A;

FIG. 3 is a partial cross-sectional view of a second embodiment of a milling cutter head for preventing breakage in accordance with the present utility model;

FIG. 4 is a partial enlarged view at B in FIG. 3;

FIG. 5 is a partial cross-sectional view III of one embodiment of a milling cutter head for preventing breakage in accordance with the present utility model;

fig. 6 is a partial enlarged view at C in fig. 5.

Reference numerals illustrate:

the achievement of the objects, functional features and advantages of the present utility model will be further described with reference to the accompanying drawings, in conjunction with the embodiments.

Detailed Description

The following description of the embodiments of the present utility model will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

It should be noted that all directional indicators (such as up, down, left, right, front, and rear … …) in the embodiments of the present utility model are merely used to explain the relative positional relationship, movement, etc. between the components in a particular posture (as shown in the drawings), and if the particular posture is changed, the directional indicator is changed accordingly.

In the present utility model, unless specifically stated and limited otherwise, the terms "connected," "affixed," and the like are to be construed broadly, and for example, "affixed" may be a fixed connection, a removable connection, or an integral body; can be mechanically or electrically connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present utility model can be understood by those of ordinary skill in the art according to the specific circumstances.

In addition, if there is a description of "first", "second", etc. in the embodiments of the present utility model, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In addition, the meaning of "and/or" as it appears throughout includes three parallel schemes, for example "A and/or B", including the A scheme, or the B scheme, or the scheme where A and B are satisfied simultaneously. In addition, the technical solutions of the embodiments may be combined with each other, but it is necessary to base that the technical solutions can be realized by those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should be considered to be absent and not within the scope of protection claimed in the present utility model.

The existing milling hand machine generally comprises a handle body, a main shaft, a boot rod barrel and a boot protection boot, wherein the main shaft is connected in the handle body in a matched mode through a bearing, one end of the boot rod barrel is fixedly connected with the main shaft in the axial direction, the boot protection boot is detachably and fixedly connected with the boot rod barrel, one end of a milling cutter is inserted into the main shaft, and the other end of the milling cutter is in movable fit with the boot protection boot foot. The outer ring of the bearing limits the axial movement of the bearing through a limiting piece, and the limiting piece is arranged in the handle body and is in threaded connection with the inner wall of the handle body. When the milling mobile phone works, the motor can drive the main shaft to rotate at a high speed, and because the limiting piece is in threaded connection with the inner wall of the handle body, no matter the rotation direction of the threaded connection is the same as or opposite to the rotation direction of the main shaft, the threaded connection of the limiting piece and the inner wall of the handle body can be possibly caused to be loose when the main shaft rotates, so that the limiting piece can not limit the axial movement of the bearing, the bearing and the main shaft can move in the axial direction, and further the milling cutter and the main shaft are connected to be loose to break the cutter, and a large medical accident risk exists.

The utility model provides a milling mobile phone capable of preventing a cutter from being broken.

Referring to fig. 1 and 3, fig. 1 is a partial cross-sectional view of a first embodiment of a milling cutter for preventing a knife break according to the present utility model, and fig. 3 is a partial cross-sectional view of a second embodiment of a milling cutter for preventing a knife break according to the present utility model.

In an embodiment of the present utility model, the milling machine capable of preventing a cutter from being broken includes:

a handle body 100 provided with a receiving channel;

the main shaft assembly 200 is arranged in the accommodating channel;

bearing 300, bearing 300 has inner ring 310 and outer ring 320, inner ring 310 is set up outside main shaft assembly 200, outer ring 320 is abutted against inner wall of the accommodating channel;

the limiting piece 400, one end of the limiting piece 400 is abutted with the outer ring 320, and the other end of the limiting piece 400 extends towards the direction away from the bearing 300;

the positioning member 500 connects one end of the stopper 400 away from the bearing 300 and the shank 100.

The milling hand machine in one technical scheme of the embodiment of the utility model comprises a handle body 100, a spindle assembly 200, a bearing 300, a limiting piece 400 and a positioning piece 500, wherein the spindle assembly 200 is used for connecting a driving piece and a milling cutter, an inner ring 310 of the bearing 300 is sleeved outside the spindle assembly 200, the peripheral surface of an outer ring 320 of the bearing 300 is abutted with the inner wall of a containing channel, and therefore the spindle assembly 200 is guaranteed to rotate well in the containing channel. One end of the stopper 400 abuts against the side wall of the outer ring 320 of the bearing 300, and the other end of the stopper 400 is fixed to the inner wall of the receiving channel through the positioning member 500, thereby restricting the movement of the bearing 300 in the axial direction. The locating part 400 laminating holds the inner wall of passageway, does not have threaded connection between locating part 400 and the inner wall of holding the passageway, can improve the axiality of locating part 400 and handle body 100, reduces the vibration of milling the cell-phone during operation, can also reduce the processing degree of difficulty of locating part 400 and handle body 100 simultaneously. The limiting piece 400 and the handle body 100 are not in threaded connection, so that the connection with the handle body 100 is not loosened due to the rotation of the spindle assembly 200, the positioning piece 500 can directly penetrate through the limiting piece 400 and the handle body 100 and is fixed in a threaded connection or welding mode, the connection strength of the positioning piece 500 is not basically influenced by the rotation of the spindle assembly 200, the bearing 300 and the spindle assembly 200 are difficult to move in the axial direction, and the possibility of cutter breakage of the milling cutter is reduced.

Optionally, the limiter 400 includes:

a supporting portion 410 sleeved outside the spindle assembly 200, wherein one end of the supporting portion 410 abuts against the outer ring 320, and the other end of the supporting portion 410 extends in a direction away from the bearing 300;

the positioning part 420 is arranged on the periphery of the supporting part 410, the inner wall of the accommodating channel is provided with a step structure corresponding to the positioning part 420, the positioning part 420 is provided with a positioning hole 421, and the positioning piece 500 passes through the positioning hole 421 and is in threaded connection with the step structure.

Referring to fig. 4, in the present embodiment, the limiting member 400 includes a supporting portion 410 and a positioning portion 420, the supporting portion 410 is attached to an inner wall of the accommodating channel, and mainly plays a role in limiting movement of the bearing 300, and the positioning portion 420 is disposed on an outer periphery of the supporting portion 410 and is used for connecting with the handle body 100. In order to facilitate the use of the user, the milling mobile phone needs to have a certain length, so that the length of the spindle assembly 200 is longer, and the bearing 300 needs to be arranged at the relative middle position of the spindle assembly 200 to ensure the rotation of the spindle assembly 200, so that the support part 410 and the positioning part 420 are arranged to conveniently limit the bearing 300 and fix the limiting piece 400. The inner wall of the accommodating channel is provided with a step structure corresponding to the positioning part 420, the positioning part 420 is provided with a positioning hole 421 corresponding to the positioning piece 500, and the positioning piece 500 passes through the positioning hole 421 to be in threaded connection with the step structure, so that the structure is simple and the processing is convenient.

Optionally, the positioning hole 421 includes a first sub-hole 4211 and a second sub-hole 4212, where the first sub-hole 4211 is connected, and the second sub-hole 4212 is disposed on a side of the first sub-hole 4211 facing away from the step structure, and a diameter of the second sub-hole 4212 is larger than a diameter of the first sub-hole 4211.

Referring to fig. 4, in the present embodiment, the positioning hole 421 includes a first sub-hole 4211 and a second sub-hole 4212, the first sub-hole 4211 is disposed at a side of the positioning portion 420 facing the step structure, and a diameter of the second sub-hole 4212 is larger than a diameter of the first sub-hole 4211. 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, so that on one hand, the aesthetic degree of the milling machine is improved, and on the other hand, the exposed screw head can be prevented from scratching the user. The circumference array of locating hole 421 is equipped with a plurality ofly, corresponds every locating hole 421 and is equipped with a setting element 500, can improve the joint strength between locating part 400 and the handle body 100, further reduces the likelihood of breaking the sword.

Optionally, the milling machine further includes:

an end stop 600 fixed to an end of the shank 100 remote from the positioning member 500;

the lock sleeve 700 is sleeved on the handle body 100 and the end baffle 600 and is in threaded connection with the periphery of the handle body 100, the end baffle 600 and the lock sleeve 700 jointly enclose to form a containing cavity, and the volume of the containing cavity is adjustable due to the axial movement of the lock sleeve 700 along the handle body 100;

the blocking member 800 is disposed inside the accommodating cavity and sleeved on the handle body 100.

Referring to fig. 2, 5 and 6, in this embodiment, the milling machine further includes an end stop 600, a lock sleeve 700 and a blocking member 800, and the lock sleeve 700 can move along the axial direction of the handle 100 through the threaded connection between the lock sleeve 700 and the handle 100, the lock sleeve 700 moves away from the end stop 600, so that the milling cutter can be locked with the spindle assembly 200, and the lock sleeve 700 moves towards the direction close to the end stop 600, so that the milling cutter can be separated from the spindle assembly 200. The end stop 600 is used for preventing the lock sleeve 700 from being separated from the handle body 100, and in this embodiment, the end stop 600 is a nut, is screwed with one end of the handle body 100, and is fixed with the handle body 100 by welding or bonding, so that the spindle assembly 200 can be prevented from rotating, and the nut is prevented from loosening and falling off, so that the lock sleeve 700 cannot be prevented from being separated from the handle body 100. When the milling cutter needs to be separated from the spindle assembly 200, the user turns the lock sleeve 700 to move towards the direction approaching the end stop 600, and the lock sleeve 700 is turned by hands, so that the friction coefficient is larger due to the self material of the lock sleeve 700, when the lock sleeve 700 is tightly attached to the end stop 600, the static friction force between the lock sleeve 700 and the end stop 600 is easily larger, and then the lock sleeve 700 is turned towards the direction far away from the end stop 600, so that the problem of more laborious and even dead locking can occur. The blocking member 800 is sleeved on the handle body 100 and is arranged between the lock sleeve 700 and the end baffle 600 to separate the lock sleeve 700 and the end baffle 600, and the friction coefficient between the blocking member 800 and the lock sleeve 700 and the friction coefficient between the blocking member 800 and the end baffle 600 are smaller, so that the blocking member 800 and the lock sleeve 700 are difficult to block, and meanwhile, the blocking member 800 and the end baffle 600 are difficult to block, so that the possibility that the lock sleeve 700 is blocked at a position close to the end baffle 600 is reduced.

Optionally, the lock sleeve 700 has a first side wall 710 and a second side wall 720 adjacent to each other, the end shield 600 has a third side wall 610 and a fourth side wall 620 adjacent to each other, the first side wall 710, the second side wall 720, the fourth side wall 620 and the handle body 100 collectively enclose a receiving cavity, the first side wall 710 abuts against the third side wall 610, the second side wall 720 is opposite to the fourth side wall 620, the second side wall 720 is close to or far from the fourth side wall 620 by movement of the lock sleeve 700, the barrier 800 has an arc wall, and the barrier 800 abuts against the second side wall 720 and the fourth side wall 620 by the arc wall.

Referring to fig. 2, in the present embodiment, the lock sleeve 700 has a first side wall 710 and a second side wall 720 that are adjacent to each other, the end shield 600 has a third side wall 610 and a fourth side wall 620 that are adjacent to each other, and the first side wall 710, the second side wall 720, the fourth side wall 620 and the handle body 100 jointly enclose to form a receiving cavity, so that the lock sleeve 700 can also play a certain role in protecting, and the possibility that liquid enters the interior of the milling machine from between the lock sleeve 700 and the handle body 100 during the working or cleaning and disinfecting process of the milling machine is reduced. The third side wall 610 and the fourth side wall 620 adjacent to the end stop 600 form edges, when the lock sleeve 700 drives the stop 800 to abut against the end stop 600, the end stop 600 abuts against the arc wall of the stop 800 through the edges, so that the force transmission direction between the stop 800 and the end stop 600 is inclined to the axial direction of the lock sleeve 700, that is, the positive pressure between the stop 800 and the end stop 600 is reduced, the static friction force between the stop 800 and the end stop 600 is reduced, and the problem of blocking between the stop 800 and the end stop 600 is not easy to occur.

Alternatively, the barrier 800 is ring-shaped with an opening.

In this embodiment, the blocking member 800 is in a ring shape with an opening, when the milling machine is sterilized at high temperature, the milling machine is generally separated from the spindle assembly 200, i.e. the lock sleeve 700 is located near the end blocking member 600 with a high probability, i.e. the lock sleeve 700 is in a state of abutting the blocking member 800 and the blocking member 800 abuts the end blocking member 600, the lock sleeve 700, the handle body 100, the end blocking member 600 and the like are slightly expanded due to the high temperature, the lock sleeve 700, the blocking member 800 and the end blocking member 600 are mutually extruded, so that positive pressure between the lock sleeve 700 and the blocking member 800 and between the blocking member 800 and the end blocking member 600 is increased, the lock sleeve 700 is easy to be blocked, the blocking member 800 is in a ring shape with an opening, a space for the lock sleeve 700, the blocking member 800 and the end blocking member 600 to be expanded due to the high temperature is reserved, and the possibility of blocking the lock sleeve 700 and the end blocking member 600 is reduced.

Alternatively, the barrier 800 is a circlip 900 for holes.

In this embodiment, the blocking member 800 is a hole steel wire retainer ring 900, and the end face of the lock sleeve 700 is isolated from the end face of the end blocking member 600 by the hole steel wire retainer ring 900, so that the possibility that the lock sleeve 700 is blocked due to too tight contact with the end blocking member 600 during screwing is reduced, and the hole steel wire retainer ring 900 is easy to select, easy to purchase and low in cost.

Alternatively, the first sidewall 710 is provided with a first mounting groove 711 corresponding to the blocking member 800, the first mounting groove 711 is recessed in a direction away from the accommodating cavity, and the blocking member 800 is partially disposed inside the first mounting groove 711.

Referring to fig. 2, in the present embodiment, a first mounting groove 711 is provided on the first side wall 710 corresponding to the blocking member 800, and the blocking member 800 is disposed in the first mounting groove 711, so that the blocking member 800 is convenient to limit on one hand, and easy to process on the other hand.

Optionally, the spindle assembly 200 includes:

a connection shaft 210, a first end of the connection shaft 210 being used for connecting a driving member;

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

the connection pin 230, the connection sleeve 220 and the second end of the connection shaft 210, and the inner ring 310 of the bearing 300 is sleeved outside the sleeve 220 and covers the connection pin 230.

Referring to fig. 2, in the present embodiment, the spindle assembly 200 includes a connecting shaft 210, a sleeve 220 and a connecting pin 230, a first end of the connecting shaft 210 is connected with a driving member, which may be a motor or a speed reducer, and a second end of the connecting shaft 210 is connected with the sleeve 220, so that the problems of large processing difficulty, difficulty in ensuring coaxiality and the like are easily caused by too long spindle size of the milling machine, and the processing difficulty can be reduced and the manufacturing precision can be improved by two-stage design of the connecting shaft 210 and the sleeve 220, thereby ensuring that the spindle assembly 200 can rotate stably at a high speed and further reducing the possibility of cutter breakage. One end of the sleeve 220 is sleeved at the second end of the connecting shaft 210, the other end of the sleeve 220 is used for fixing a milling cutter, and the connecting pin 230 penetrates through the connecting shaft 210 and the sleeve 220, so that the sleeve 220 and the connecting shaft 210 are fixed, the structure is simple, and the assembly and the disassembly are convenient. The inner ring 310 of the bearing 300 is sleeved outside the sleeve 220 and covers the connection pin 230, and can prevent the connection pin 230 from being removed during high-speed operation.

Optionally, the outer circumference of sleeve 220 is provided with a second mounting groove, in which a retainer ring 900 is provided, retainer ring 900 abutting inner ring 310 to limit axial movement of bearing 300.

Referring to fig. 2, in the embodiment, the retainer ring 900 is used to limit the axial movement of the inner ring 310 of the bearing 300, a second mounting groove is formed on the outer periphery of the sleeve 220 corresponding to the retainer ring 900, a part of the retainer ring 900 is located in the second mounting groove, and another part of the retainer ring 900 extends out of the second mounting groove to abut against the side wall of the inner ring 310 of the bearing 300, so that the limit of the bearing 300 is realized, the structure is simple, and the disassembly and assembly are convenient.

The foregoing description is only of the optional embodiments of the present utility model, and is not intended to limit the scope of the utility model, and all the equivalent structural changes made by the description of the present utility model and the accompanying drawings or the direct/indirect application in other related technical fields are included in the scope of the utility model.

Claims

1. A milling machine capable of preventing a cutter from being broken, comprising:

a handle body provided with a receiving channel;

the main shaft assembly is arranged in the accommodating channel;

2. The anti-breaking milling machine of claim 1, wherein the stop comprises:

3. The hand milling machine for preventing a knife break according to claim 2, wherein the positioning hole comprises a first sub-hole and a second sub-hole which are communicated, the second sub-hole is arranged on one side of the first sub-hole away from the step structure, and the diameter of the second sub-hole is larger than that of the first sub-hole.

4. The break-preventing milling cutter hand piece of claim 1, further comprising:

5. The anti-breaking milling machine of claim 4, wherein the sleeve has first and second adjacent side walls, the end stop has third and fourth adjacent side walls, the first, second, fourth and shank together enclose the receiving cavity, the first side wall is in abutment with the third side wall, the second side wall is disposed opposite the fourth side wall, the second side wall is moved toward or away from the fourth side wall by movement of the sleeve, the stop has an arcuate wall, and the stop abuts the second and fourth side walls by the arcuate wall.

6. The break-preventing milling machine of claim 5 wherein the barrier is annular with an opening.

7. The break-preventing milling machine of claim 6 wherein the barrier is a hole wire retainer ring.

8. The hand milling machine for preventing a knife break according to claim 5, wherein the first side wall is provided with a first mounting groove corresponding to the blocking member, the first mounting groove is recessed in a direction away from the accommodating cavity, and the blocking member is partially arranged in the first mounting groove.

9. The anti-breaking milling machine of claim 1, wherein the spindle assembly comprises:

the first end of the connecting shaft is used for connecting the driving piece;

the sleeve is sleeved at the second end of the connecting shaft;

10. The break-preventing milling machine of claim 9, wherein the outer circumference of the sleeve is provided with a second mounting groove, and a retainer ring is provided in the second mounting groove, and the retainer ring abuts against the inner ring to limit the axial movement of the bearing.