CN217793242U - Medical planing device capable of preventing negative pressure loss - Google Patents

Abstract

The utility model discloses a prevent medical planing device that negative pressure runs off, include: the planing cutter comprises an outer cutter pipe assembly and an inner cutter pipe assembly, the outer cutter pipe assembly comprises an outer cutter pipe and a cutter handle, and the tail end of the outer cutter pipe is inserted into a central hole of the cutter handle; the inner cutter tube assembly comprises an inner cutter tube and a connecting piece, and the inner cutter tube is arranged in the outer cutter tube and can rotate around the axis of the inner cutter tube; the handle comprises a handle shell, the head end of the handle shell is provided with a jack, and the cutter handle is inserted into the jack; further comprising: the at least two sealing rings are axially arranged between the outer wall of the handle and the inner wall of the insertion hole at intervals and used for sealing a gap between the handle and the handle shell. The medical planing device for preventing the negative pressure loss provided by the utility model can stabilize the sealing performance between the planing tool and the handle shell to be more than 98.5 percent, and can increase the sealing effect; moreover, the two sealing rings can ensure that the knife handle and the handle shell are matched more stably and reliably.

Description

Medical planing device capable of preventing negative pressure loss

Technical Field

The utility model relates to the technical field of medical equipment, especially, relate to a prevent medical planing device that negative pressure runs off.

Background

The planing tool is applied to arthroscopic surgery, ear-nose-throat surgery and other surgeries. The existing planing tool generally comprises an outer cutter pipe assembly and an inner cutter pipe assembly which is arranged in the outer cutter pipe assembly and can rotate relative to the outer cutter pipe assembly, an outer cutter head is arranged at the head end of the outer cutter pipe assembly, an inner cutter head is arranged at the head end of the inner cutter pipe assembly, when the inner cutter pipe assembly rotates relative to the outer cutter pipe assembly, the outer cutter head and the inner cutter head move relatively to cut off human tissues, and mixed liquid of the cut-off tissues and physiological saline is discharged from the inner cutter head through the inner cutter pipe of the inner cutter pipe assembly and then through a negative pressure suction system.

After the existing planing tool is installed and matched with a handle shell, a single end face sealing ring arranged at the tail part of an outer tool tube component is usually used for sealing, the sealing ring is matched with the handle shell and cannot realize complete and thorough sealing, and partial negative pressure often flows from gaps between an inner tool bit and an outer tool bit and between the inner tool tube and the outer tool tube during the operation of planing tissues, so that the suction and planing efficiency of the planing tool are reduced; meanwhile, the planed tissues such as human fascia enter the gaps between the inner cutter head and the outer cutter head as well as the inner cutter tube and the outer cutter tube, so that the normal operation of the cutter is influenced, and the planing efficiency and the suction efficiency of the cutter are further reduced.

SUMMERY OF THE UTILITY MODEL

To the above-mentioned prior art current situation, the utility model aims to solve the technical problem that a medical planing device that prevents negative pressure loss is provided to improve planing and suction efficiency.

In order to solve the technical problem, the utility model provides a prevent medical planing device of negative pressure loss which provides, include: the planing cutter comprises an outer cutter pipe assembly and an inner cutter pipe assembly, wherein the outer cutter pipe assembly comprises an outer cutter pipe and a cutter handle, the cutter handle is provided with a center hole which penetrates through the cutter handle along the axial direction, and the tail end of the outer cutter pipe is inserted into the center hole of the cutter handle; the inner cutter tube assembly comprises an inner cutter tube and a connecting piece, the inner cutter tube is arranged in the outer cutter tube and can rotate around the axis of the inner cutter tube, and the tail end of the inner cutter tube extends out of the tail end of the outer cutter tube and is connected with the head end of the connecting piece; the handle comprises a handle shell, the head end of the handle shell is provided with a jack, and the tool shank is inserted into the jack; further comprising: the sealing rings are axially arranged between the outer wall of the handle and the inner wall of the jack at intervals and are used for sealing a gap between the handle and the handle shell.

The medical planing device for preventing the negative pressure loss provided by the utility model has the advantages that the two sealing rings are arranged between the tool handle and the handle shell, so that the sealing performance between the planing tool and the handle shell is stabilized to be more than 98.5 percent, and the sealing effect can be improved; moreover, the two sealing rings can ensure that the knife handle is matched with the handle shell more stably and reliably.

In one embodiment, the outer peripheral surface of the tool shank is provided with at least two annular mounting grooves respectively, and at least two sealing rings are mounted in the at least two mounting grooves respectively.

In one embodiment, a seal is further included, the seal being disposed between the outer and inner blade tube assemblies for sealing a gap between the outer and inner blade tube assemblies.

In one embodiment, the center hole of the tool holder comprises a mounting hole section and a hole expanding section located on the rear side of the mounting hole section, the inner diameter of the hole expanding section is larger than that of the mounting hole section, the tail end of the outer tool tube is mounted in the mounting hole section, the inner tool tube comprises an extending section located in the hole expanding section, and the sealing element is arranged between the outer wall of the extending section and the inner wall of the hole expanding section.

In one embodiment, the sealing member includes an annular main body portion that is fitted over the extension section, and a cylindrical edge portion that extends from a radially outer end of the main body portion toward a trailing end side of the inner tool tube in an axial direction of the inner tool tube, and a radially inner end of the main body portion is provided with a first sealing portion that engages with an outer wall of the extension section, and the edge portion is provided with a second sealing portion that engages with an inner wall of the reamer section.

In one embodiment, the side of the main body part facing the head end of the inner cutter tube comprises at least one pressure-bearing inclined surface, the pressure-bearing inclined surface is annular and surrounds along the axis of the main body part, and the radial outer end of the pressure-bearing inclined surface is inclined towards the tail end side or the head end side of the inner cutter tube relative to the radial inner end of the pressure-bearing inclined surface.

In one embodiment, the pressure-bearing inclined surface includes a first inclined surface and a second inclined surface which are sequentially arranged from inside to outside from the center of the main body portion, a radially outer end of the first inclined surface is inclined toward a tail end side of the inner cutter pipe with respect to a radially inner end thereof, and a radially outer end of the second inclined surface is inclined toward a head end side of the inner cutter pipe with respect to a radially inner end thereof.

In one embodiment, at least one groove is arranged on the side surface of the main body part facing the tail end side of the inner cutter tube and/or the inner side surface of the edge part.

In one embodiment, the projecting section is provided with a sleeve of self-lubricating material.

In one embodiment, a thrust member is disposed within the reamer section to limit movement of the seal member toward the trailing end side of the inner cutter tube.

The advantageous effects of the additional features of the present invention will be explained in the detailed description of the preferred embodiments of the present description.

Drawings

Fig. 1 is a schematic structural view of a medical planing device according to a first embodiment of the present invention;

FIG. 2 is an enlarged partial view of FIG. 1 at M;

fig. 3 is a schematic view of a planing tool of the medical planing device shown in fig. 1;

FIG. 4 is an enlarged view of a portion of FIG. 3 at W;

FIG. 5 is a perspective view of a seal of the planing tool shown in FIG. 3;

FIG. 6 is a cross-sectional view of the seal shown in FIG. 5;

FIG. 7 is an enlarged view of a portion of FIG. 6 at A;

FIG. 8 is an enlarged partial view of FIG. 6 at B;

FIG. 9 is a perspective view of a thrust member of the planing tool shown in FIG. 3;

fig. 10 is a perspective view of a sealing member according to a second embodiment of the present invention;

FIG. 11 is a cross-sectional view of the seal shown in FIG. 10;

FIG. 12 is an enlarged partial view at C of FIG. 11;

fig. 13 is an enlarged partial view of fig. 11 at D.

Description of reference numerals:

1. a handle; 12. a handle housing; 121. a jack; 122. a suction channel; 13. a drive motor; 14. an output shaft; 15. a control valve; 2. a knife handle; 21. a central bore; 21a, a reaming section; 21b, a middle hole section; 21c, step surfaces; 21d, internal threads; 21e, mounting hole sections; 22. a first mounting groove; 23. a second mounting groove; 3. an outer cutter tube; 31. an outer cutter head; 4. an inner cutter tube; 41. an inner cutter head; 42. a protruding section; 5. a seal member; 51. a main body portion; 52. an edge portion; 53. a first sealing rib; 54. a second sealing rib; 55. a pressure bearing inclined plane; 55a, a first inclined plane; 55b, a second inclined plane; 57. a first groove; 58. a second groove; 59. parting grooves; 6. a thrust member; 61. an external thread; 62. an inner corner hole; 7. a first seal ring; 8. a second seal ring; 9. a retainer ring; 10. a connecting member; 101. a suction hole; 11. and (4) sleeving the sleeve.

Detailed Description

In order to make the above objects, features and advantages of the present invention more comprehensible, embodiments of the present invention are described in detail below with reference to the accompanying drawings. It is apparent that the specific details set forth in the following description are merely exemplary of the invention, which can be practiced in many other embodiments that depart from the specific details disclosed herein. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work all belong to the protection scope of the present invention.

When an element is referred to herein as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The directional terms front, rear, upper and lower are defined as the positions of the components in the drawings and the positions of the components relative to each other, and are used for the sake of clarity and convenience in technical solution. It is to be understood that the use of the directional terms should not be taken to limit the scope of the claims.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

Referring to fig. 1 and 2, a medical planing device according to a first embodiment of the present invention includes a handle 1 and a planing tool, wherein the handle 1 includes a handle housing 12 and a tool driving device, and the handle housing 12 is substantially cylindrical so as to be easily held by hand. The head end of the handle case 12 is provided with an insertion hole 121 into which a planing tool is inserted, and the tool driving device is provided in the handle case 12 at the rear side of the insertion hole 121. The exemplary tool driving device includes a driving motor 13, a transmission mechanism and a control circuit (not shown), wherein a rotating shaft of the driving motor 13 is in transmission connection with an input shaft of the transmission mechanism, and an output shaft 14 of the transmission mechanism is connected with the planing tool. The transmission mechanism can be a magnetic transmission mechanism or a gear transmission mechanism. A suction channel 122 is also provided on the handle housing 12, and a control valve 15 is provided on the suction channel 122.

Referring to fig. 3 to 4, an exemplary planing tool includes an outer cutter pipe assembly, an inner cutter pipe assembly and a sealing member 5, the outer cutter pipe assembly includes an outer cutter pipe 3 and a tool shank 2, one end of the outer cutter pipe 3 is a head end (i.e., an end far away from the tool shank 1), the other end is a tail end (i.e., an end close to the tool shank 1), an outer cutter head 31 is disposed at the head end of the outer cutter pipe 3, and an outer cutting window and outer cutting teeth disposed at an edge of the outer cutting window are disposed on the outer cutter head 31. The tool holder 2 is a cylindrical structure extending along the axial direction of the outer tool tube 3, a center hole 21 is formed in the center of the outer tool tube 3, and the tail end of the outer tool tube 3 is inserted into the head end of the center hole 21 of the tool holder 2.

As shown in fig. 2, the holder 2 is inserted into the insertion hole 121 formed in the head end of the handle case 12, and the seal rings 7 and 8 are provided between the holder 2 and the handle case 12 to seal the gap between the holder 2 and the handle case 12 and prevent the negative pressure from flowing out from the gap between the planing tool and the handle case 12. By way of example, the sealing rings include a first sealing ring 7 and a second sealing ring 8, and the first sealing ring 7 and the second sealing ring 8 are arranged at intervals along the axial direction of the tool shank 2. Through tests, two sealing rings are arranged between the tool shank 2 and the handle shell 12, so that the sealing performance between the planing tool and the handle 1 is stabilized to be more than 98.5% (namely, a nominal negative pressure value is-40 KPa, and the actually measured negative pressure of the tool bit is more than 39.5 KPa), and compared with an end face sealing ring arranged at the tail end of the tool shank, the sealing effect can be greatly improved; moreover, the two sealing rings can ensure that the tool handle 2 and the handle shell 12 are matched more stably and reliably. In this embodiment, the outer peripheral surfaces of the head end and the rear end of the tool holder 2 are respectively provided with an annular first mounting groove 22 and an annular second mounting groove 23, and the first sealing ring 7 and the second sealing ring 8 are respectively mounted in the first mounting groove 22 and the second mounting groove 23. As an alternative, more than two (e.g., 3) sealing rings may be further disposed between the outer wall of the tool holder and the inner wall of the insertion hole, a corresponding number of mounting grooves are disposed on the outer circumferential surface of the tool holder, and the more than two sealing rings are respectively mounted in the mounting grooves.

As shown in fig. 3 and 4, the inner cutter tube assembly includes an inner cutter tube 4 and a coupling 10, and the inner cutter tube 4 is disposed inside the outer cutter tube 3 and is rotatable about its axis. One end of the inner cutter tube 4 is a head end (i.e. the end far away from the handle 1), the other end is a tail end (i.e. the end close to the handle 1), the head end of the inner cutter tube 4 is provided with an inner cutter head 41, and the inner cutter head 41 is provided with an inner cutting window and inner cutting teeth arranged on the edge of the inner cutting window. The tail end of the inner knife pipe 4 extends out of the outer knife pipe 3 and is connected with the head end of the connecting piece 10, the rear end of the connecting piece 10 is connected with the output shaft 14, and the connecting piece 10 is provided with a suction hole 101 which penetrates in the radial direction. When the driving motor 13 works, the driving motor 13 drives the output shaft 14 to rotate, the output shaft 14 drives the connecting piece 10 to rotate, so as to drive the inner cutter tube 4 to rotate, when the inner cutter tube 4 rotates, the inner cutting teeth on the inner cutter head 41 and the outer cutting teeth on the outer cutter head 31 do relative motion to cut off soft tissues, the mixed liquid of the cut-off tissues and the physiological saline is sucked into the inner cutter tube 4 through the inner cutting window, and then the mixed liquid is sucked out through the suction hole 101 on the connecting piece 10 and the suction channel 122 on the handle shell 12, so that the cutting purpose is achieved.

As shown in fig. 2, a boss 102 is provided on the outer peripheral surface of the head end of the connecting member 10, a retaining ring 9 is provided in the rear end of the center hole 21 of the tool shank 2, the inner diameter of the retaining ring 9 is smaller than the outer diameter of the boss 102, and the inner tool tube assembly is prevented from falling off by the retaining ring 9.

As shown in fig. 3 and 4, a seal 5 is provided between the outer and inner knife tube assemblies for sealing a gap between the outer and inner knife tube assemblies. By arranging the sealing element 5 between the outer cutter pipe component and the inner cutter pipe component, the outer cutter pipe component and the inner cutter pipe component are well sealed, negative pressure is prevented from flowing from gaps between the inner cutter head 31 and the outer cutter head 31 and between the inner cutter pipe 3 and the outer cutter pipe 3 and entering the gaps, tissues and negative pressure are enabled to intensively pass through the suction channel 122 of the inner cutter pipe 4, the planing efficiency and the suction efficiency can be effectively improved, and cutter blockage is prevented; meanwhile, since the gap between the outer and inner blade tube assemblies before the sealing member 5 is communicated with the outside (i.e., high pressure region), and the gap between the outer and inner blade tube assemblies after the sealing member 5 is communicated with the negative pressure system (low pressure region), the pressures at the left and right sides of the sealing member 5 are different, thereby generating a pressure difference at the left and right sides of the sealing member 5, which can deform the sealing member 5 to achieve good sealing with the outer and inner blade tube assemblies.

As an example, the central hole 21 of the tool holder 2 includes a mounting hole section 21e that is engaged with the tail end of the outer tool tube 3 and a reaming section 21a located at the rear side of the mounting hole section 21e, the inner diameter of the reaming section 21a is larger than that of the mounting hole section 21e, the inner tool tube 4 includes a protruding section 42 located in the reaming section 21a, and the sealing member 5 is disposed between the outer wall of the protruding section 42 and the inner wall of the reaming section 21 a. Thus, the space for installing the seal 5 is large, and the seal 5 is convenient to install. Alternatively, the seal 5 may also be provided between the tube body of the inner cutter tube 4 and the tube body of the outer cutter tube 3 or between the inner cutter head 41 and the outer cutter head 31.

As shown in fig. 5 to 8, the exemplary sealing member 5 includes a ring-shaped main body portion 51 fitted over the protruding portion 42, and a cylindrical edge portion 52 formed by extending from a radially outer end of the main body portion 51 toward the trailing end side of the inner cutter pipe 4 in the axial direction of the inner cutter pipe 4, wherein a first sealing portion engaged with an outer wall of the protruding portion 42 is provided on a radially inner end of the main body portion 51, and a second sealing portion engaged with an inner wall of the expanding portion 21a is provided on the edge portion 52. In this way, the edge portion 52 and the main body portion 51 form a bowl-shaped structure, and the sealing member 5 of this bowl-shaped structure is easily deformed when a pressure difference is applied, and further, the first seal portion and the second seal portion of the sealing member 5 are deformed to achieve good sealing.

Preferably, the side of the main body 51 facing the head end of the inner cutter tube 4 includes at least one pressure-bearing slope 55, the pressure-bearing slope 55 is annular and surrounds along the axis of the main body 51, and the radially outer end of the pressure-bearing slope 55 is inclined toward the tail end side of the inner cutter tube 4 (or toward the head end side of the inner cutter tube 4) with respect to the radially inner end thereof. According to the pressure = pressure × area, under the same pressure, the larger the area is, the larger the pressure value is, so that the pressure applied to the sealing element 5 can be increased by providing the pressure-bearing inclined surface 55 on the side surface of the sealing element 5 contacting the high-pressure region, thereby increasing the deformation of the sealing element 5 and increasing the sealing effect.

As shown in fig. 6, the main body 51 is provided with at least one annular first groove 57 on the side facing the trailing end side of the inner tube 4, and the rim 52 is provided with at least one annular second groove 58 on the inner side. The first and second grooves 57, 58 make it easier for the seal 5 to deform when subjected to a pressure difference, resulting in a better seal.

As shown in fig. 6 and 7, the first sealing portion of the embodiment includes at least two first sealing ribs 53 arranged at intervals along the axial direction of the inner cutting tube 4, and the inner diameters of the at least two first sealing ribs 53 gradually decrease from the head end to the tail end of the inner cutting tube 4 (i.e., the inner diameter d1> d2> d3 shown in fig. 7), so that it is ensured that the interference between all the first sealing ribs 53 and the protruding section 42 is the same when the sealing member 5 is deformed by pressure, so as to achieve better sealing. As an example, the cross section of the first sealing rib 53 is semicircular, and a groove is provided between two adjacent first sealing ribs 53. The first sealing rib 53 of this structure has a good sealing effect.

As shown in fig. 6 and 8, the second sealing portion includes at least two second sealing ribs 54 arranged at intervals along the axial direction of the inner cutter tube 4, and the outer diameter of the second sealing ribs 54 gradually increases from the head end to the tail end of the inner cutter tube 4 (i.e., the outer diameter D1< D2< D3 shown in fig. 8), so that it can be ensured that the interference between all the second sealing ribs 54 and the inner wall of the reaming section 21a is the same when the sealing member 5 is deformed by pressure, so as to achieve better sealing. By way of example, the cross section of the second sealing rib 54 is a right trapezoid, and a groove is provided between two adjacent second sealing ribs 54. The second sealing rib 54 with the structure is easier to deform, has good sealing effect and high strength, and is not easy to damage.

As shown in fig. 4, the protruding section 42 is provided with a sleeve 11 made of self-lubricating material (such as vinylidene) for example, so that the sleeve 11 has a high surface finish, and can achieve a good fit seal with the first sealing portion of the sealing member 5, and the tool can maintain a good sealing effect in a long-term operation state.

As shown in fig. 4, a thrust piece 6 for restricting the movement of the seal 5 toward the trailing end side of the inner cutter tube 4 is provided in the reamer section 21a on the rear side of the seal 5 as an example. When the sealing element 5 is deformed by pressure difference, the thrust member 6 can prevent the sealing element 5 from moving to the right side, so that the sealing element 5 can only move in the radial direction, the first sealing rib 53 is reliably sealed with the outer wall of the extending part, and the second sealing rib 54 is reliably sealed with the inner wall of the reaming section 21a, thereby increasing the sealing effect.

As shown in fig. 4, the thrust member 6 is movably connected to the shank 2 in the axial direction of the reaming section 21a, the central bore 21 further includes an intermediate bore section 21b located between the reaming section 21a and the mounting bore section 21e, the inner diameter of the intermediate bore section 21b is smaller than the inner diameter of the reaming section 21a so as to form a stepped surface 21c between the intermediate bore section 21b and the reaming section 21a, and the stepped surface 21c is in sealing engagement with the side surface of the main body portion 51 facing the head end of the inner cutter tube 4. Thus, when the thrust member 6 is moved forward, the pressure-receiving inclined surface 55 of the seal member 5 engages with the stepped surface 21c to effect sealing, thereby achieving natural sealing without a pressure difference. The thrust member 6 is provided with an external thread 61 as an example, the inner wall of the central hole 21 is provided with an internal thread 21d which is matched with the external thread 61, and the thrust member 6 is connected with the tool shank 2 through the external thread 61 and the internal thread 21d, so that the position of the thrust member 6 can be adjusted by rotating the thrust member 6. For convenience of adjustment, the center of the thrust member 6 is provided with an adjustment hole 62, and the adjustment hole 62 may be a hexagon socket.

Fig. 10-13 show a schematic view of the seal 5 in another embodiment. As shown in the drawing, the structure of the seal member 5 in the present embodiment is substantially the same as that of the seal member 5 in the previous embodiment, except that the pressure-bearing slope 55 of the seal member 5 includes a first slope 55a and a second slope 55b arranged in this order from the center of the main body portion 51, the radially outer end of the first slope 55a is inclined toward the trailing end side of the inner cutter pipe 4 with respect to the radially inner end thereof, and the radially outer end of the second slope 55b is inclined toward the leading end side of the inner cutter pipe 4 with respect to the radially inner end thereof. In operation, first ramp 55a is subjected to an inwardly directed pressure F, FIG. 13 _{Inner part} Pressure F _{Inner part} The first sealing rib 53 is deformed to achieve a good sealing effect, and the second inclined surface 55b is pressed by an outward pressure F _{Outer cover} Pressure F _{Outer cover} The second sealing rib 54 is deformed to achieve a good sealing effect. Preferably, a parting groove 59 is provided between the first inclined surface 55a and the second inclined surface 55 b. When the first inclined surface 55a is subjected to the pressure F _{Inner part} The second inclined surface 55b is subjected to a pressure F _{Outer cover} When the sealing device is used, the first inclined surface 55a and the second inclined surface 55b are gradually closed, and the parting groove 59 is arranged between the first inclined surface 55a and the second inclined surface 55b, so that the first inclined surface 55a and the second inclined surface 55b are closed as much as possible, the deformation is increased, and a good sealing effect is realized.

The above embodiments only represent several embodiments of the present invention, and the description thereof is more specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the spirit of the present invention, several variations and modifications can be made, which are within the scope of the present invention.

Claims (10)

1. A medical planing device for preventing loss of negative pressure, comprising:

the planing cutter comprises an outer cutter pipe assembly and an inner cutter pipe assembly, wherein the outer cutter pipe assembly comprises an outer cutter pipe and a cutter handle, the cutter handle is provided with a center hole penetrating along the axial direction, and the tail end of the outer cutter pipe is inserted into the center hole of the cutter handle; the inner cutter tube assembly comprises an inner cutter tube and a connecting piece, the inner cutter tube is arranged in the outer cutter tube and can rotate around the axis of the inner cutter tube, and the tail end of the inner cutter tube extends out of the tail end of the outer cutter tube and is connected with the head end of the connecting piece;

the handle comprises a handle shell, the head end of the handle shell is provided with a jack, and the handle is inserted into the jack;

it is characterized by also comprising:

the at least two sealing rings are axially arranged between the outer wall of the handle and the inner wall of the insertion hole at intervals and used for sealing a gap between the handle and the handle shell.

2. The medical planing device for preventing the negative pressure from losing according to claim 1, wherein at least two annular mounting grooves are respectively formed on the outer peripheral surface of the hilt, and at least two sealing rings are respectively mounted in the at least two mounting grooves.

3. The medical planing device for preventing the loss of negative pressure as claimed in claim 1, further comprising a sealing member disposed between the outer and inner knife pipe assemblies for sealing a gap between the outer and inner knife pipe assemblies.

4. The medical planing device for preventing the negative pressure loss according to claim 3, wherein the central hole of the cutter handle comprises a mounting hole section and a reaming section located on the rear side of the mounting hole section, the inner diameter of the reaming section is larger than that of the mounting hole section, the tail end of the outer cutter tube is installed in the mounting hole section, the inner cutter tube comprises an extending section located in the reaming section, and the sealing element is arranged between the outer wall of the extending section and the inner wall of the reaming section.

5. The medical planing device for preventing negative pressure loss according to claim 4, wherein the sealing member includes a ring-shaped main body portion fitted over the protruding section and a cylindrical edge portion extending from a radially outer end of the main body portion toward a trailing end side of the inner cutter pipe in the axial direction of the inner cutter pipe, a first sealing portion engaged with an outer wall of the protruding section is provided on a radially inner end of the main body portion, and a second sealing portion engaged with an inner wall of the reaming section is provided on the edge portion.

6. The medical planing device for preventing the loss of negative pressure as claimed in claim 5, wherein the side of the main body portion facing the head end of the inner cutter pipe includes at least one pressure-bearing slope, the pressure-bearing slope is annular around the axis of the main body portion, and the radially outer end of the pressure-bearing slope is inclined with respect to the radially inner end thereof toward the tail end side or the head end side of the inner cutter pipe.

7. The medical planing device for preventing the loss of negative pressure as claimed in claim 6, wherein the pressure-bearing inclined surface includes a first inclined surface and a second inclined surface which are arranged in order from the center of the main body portion, the radially outer end of the first inclined surface is inclined toward the trailing end side of the inner cutter pipe with respect to the radially inner end thereof, and the radially outer end of the second inclined surface is inclined toward the leading end side of the inner cutter pipe with respect to the radially inner end thereof.

8. The medical planing device for preventing the loss of negative pressure as claimed in claim 5, wherein at least one groove is provided on the side of the main body portion facing the tail end side of the inner cutter tube and/or the inner side of the edge portion.

9. The medical planing device for preventing the loss of negative pressure as claimed in claim 4, wherein the protruding section is provided with a sleeve of self-lubricating material.

10. The medical planing device for preventing the loss of negative pressure as claimed in claim 4, wherein a thrust member is provided in the reaming section for limiting the movement of the sealing member toward the trailing end side of the inner cutter pipe.

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