Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K7/00—Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical driving motors or auxiliary dynamo-electric machines
  • H02K7/14—Structural association with mechanical loads, e.g. with hand-held machine tools or fans
  • H02K7/145—Hand-held machine tool
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K1/00—Details of the magnetic circuit
  • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
  • H02K1/22—Rotating parts of the magnetic circuit
  • H02K1/27—Rotor cores with permanent magnets
  • H02K1/2706—Inner rotors
  • H02K1/272—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis
  • H02K1/274—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis the rotor consisting of two or more circumferentially positioned magnets
  • H02K1/2753—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis the rotor consisting of two or more circumferentially positioned magnets the rotor consisting of magnets or groups of magnets arranged with alternating polarity
  • H02K1/278—Surface mounted magnets; Inset magnets
  • H02K1/2783—Surface mounted magnets; Inset magnets with magnets arranged in Halbach arrays
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
  • A61B17/32—Surgical cutting instruments
  • A61B17/320016—Endoscopic cutting instruments, e.g. arthroscopes, resectoscopes
  • A61B17/32002—Endoscopic cutting instruments, e.g. arthroscopes, resectoscopes with continuously rotating, oscillating or reciprocating cutting instruments
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
  • A61C1/00—Dental machines for boring or cutting ; General features of dental machines or apparatus, e.g. hand-piece design
  • A61C1/02—Dental machines for boring or cutting ; General features of dental machines or apparatus, e.g. hand-piece design characterised by the drive of the dental tools
  • A61C1/06—Dental machines for boring or cutting ; General features of dental machines or apparatus, e.g. hand-piece design characterised by the drive of the dental tools with electric drive
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K1/00—Details of the magnetic circuit
  • H02K1/02—Details of the magnetic circuit characterised by the magnetic material
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K1/00—Details of the magnetic circuit
  • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
  • H02K1/22—Rotating parts of the magnetic circuit
  • H02K1/27—Rotor cores with permanent magnets
  • H02K1/2706—Inner rotors
  • H02K1/272—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis
  • H02K1/2726—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis the rotor consisting of a single magnet or two or more axially juxtaposed single magnets
  • H02K1/2733—Annular magnets
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K21/00—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets
  • H02K21/12—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with stationary armatures and rotating magnets
  • H02K21/14—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with stationary armatures and rotating magnets with magnets rotating within the armatures
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K21/00—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets
  • H02K21/12—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with stationary armatures and rotating magnets
  • H02K21/14—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with stationary armatures and rotating magnets with magnets rotating within the armatures
  • H02K21/16—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with stationary armatures and rotating magnets with magnets rotating within the armatures having annular armature cores with salient poles
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K7/00—Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical driving motors or auxiliary dynamo-electric machines
  • H02K7/003—Couplings; Details of shafts
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
  • A61B2017/00367—Details of actuation of instruments, e.g. relations between pushing buttons, or the like, and activation of the tool, working tip, or the like
  • A61B2017/00398—Details of actuation of instruments, e.g. relations between pushing buttons, or the like, and activation of the tool, working tip, or the like using powered actuators, e.g. stepper motors, solenoids
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
  • A61B17/22—Implements for squeezing-off ulcers or the like on the inside of inner organs of the body; Implements for scraping-out cavities of body organs, e.g. bones; Calculus removers; Calculus smashing apparatus; Apparatus for removing obstructions in blood vessels, not otherwise provided for
  • A61B2017/22079—Implements for squeezing-off ulcers or the like on the inside of inner organs of the body; Implements for scraping-out cavities of body organs, e.g. bones; Calculus removers; Calculus smashing apparatus; Apparatus for removing obstructions in blood vessels, not otherwise provided for with suction of debris
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B2217/00—General characteristics of surgical instruments
  • A61B2217/002—Auxiliary appliance
  • A61B2217/005—Auxiliary appliance with suction drainage system
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
  • A61C1/00—Dental machines for boring or cutting ; General features of dental machines or apparatus, e.g. hand-piece design
  • A61C1/02—Dental machines for boring or cutting ; General features of dental machines or apparatus, e.g. hand-piece design characterised by the drive of the dental tools

Definitions

• the present invention relates to the field of micromotors intended for dental or surgical applications. It relates more specifically to a micromotor for a microdebrider provided with a cannulated shaft.
• Surgical or dental motors having a conventional (rotor-stator) architecture, generally having a permanent magnet located in the rotor or in the bipolar magnetization stator or a radial multipolar magnetization.
• a conventional (rotor-stator) architecture generally having a permanent magnet located in the rotor or in the bipolar magnetization stator or a radial multipolar magnetization.
• the presence of several magnetic poles makes it possible to obtain a more constant torque but requires the presence of blocks or laminations of ferromagnetic material with low coercivity at the level of the rotor (of the mu-metal type, or preferably iron silicon or mild steel which saturate less quickly) in order to close the field lines between the poles, and thus not lose flux intensity, the latter being correlated to the motor torque applied.
• a drive shaft be empty in the center so as to allow the aspiration of debris generated during the tissue ablation operation along an integrated rectilinear channel, in order to on the one hand to avoid having to arrange another dedicated evacuation channel, which generates additional space and complicates the cleaning operations, and on the other hand that such a channel cannot become clogged; this is the case for example for a micro-debrider, which is usually referred to as a “shaver”.
• the drive shaft is integral with the rotor and is not connected to the latter by a gear mechanism, it is necessary to provide a certain thickness made of magnetic material in order to achieve magnetic shielding.
• Halbach gratings are also known, which are used for example in brushless motors, in order to confine the magnetic flux towards the center.
• These motors have better efficiencies and produce higher torques than a conventional magnetic arrangement, while achieving self-shielding vis-à-vis the outside. Nevertheless, such motors are difficult to miniaturize because, in order to avoid end effects, and because of the difficulty of manufacturing a cylinder having a continuously varying field, they are generally designed in segments.
• Cylindrical Halbach gratings can also be used to make magnetic couplers, such as for example in the context of one of the variants of a heart pump described in the patent document US8596999.
• Micromotors are also known for surgical handpieces provided with a central cannula intended to receive a drilling tool, such as those described in the document CA3073178. There is therefore a need for a solution free from these known limitations. Summary of the invention
• An object of the present invention is to propose a solution making it possible to optimize the torque of a motor having a cannulated shaft (for example a microdebrider or shaver.
• Another object of the present invention is to allow the production of a multipolar rotor of more efficient construction, providing better efficiencies in terms of transmission.
• a rotary micromotor arranged to actuate an abrasive blade of a surgical or dental tool, comprising a rotor cooperating with a stator, the rotary motor being characterized in that the rotor has a tubular part central hollow, and includes an outwardly polarized Halbach grating.
• An advantage of the proposed solution is to maximize the volume available for magnets by dispensing with an internal shielding sheath made of magnetic material.
• Another advantage of the proposed solution is to allow a reduction in the inertia of the rotor.
• Yet another advantage conferred by this solution is to densify the magnetic field lines on the periphery of the shaft, which makes it possible to increase the applied torque and therefore the driving power at the same time.
• the hollow central tubular part of the rotor is a cannulated shaft, the internal wall of which is adapted to form a suction channel for a micro-debrider. It is thus possible to improve the performance of such a motor compared to a conventional solution using radially oriented magnets while at the same time optimizing the given diameter of the internal duct of a cannulated shaft according to the desired flow properties.
• the internal wall of the cannulated shaft is made of an austenitic stainless steel material.
• An advantage of this solution is to facilitate the cleaning and sterilization process without requiring an additional or dedicated sheath.
• the internal wall of the cannulated shaft is made of a material and/or covered with a layer of hydrophobic and/or anti-microbial coating.
• An advantage of this solution is to facilitate the flow of fluid and/or to contrast the deposition of blood and/or proteins and/or to have an antimicrobial action.
• the internal wall of the cannulated shaft can therefore, for example, be coated with a polymer based on fluorides or with a thin layer based on titanium oxide (Ti02) or other chemical compounds of titanium.
• said internal wall of the cannulated shaft is covered with alternating hydrophobic and hydrophilic layers.
• the micromotor also comprises a device for coupling to the abrasive blade which is arranged along the axis of rotation of the rotor.
• a direct-drive arrangement dispenses with any intermediate gear mechanism between the motor and the blade, which minimizes space in the handpiece on the one hand and power losses on the other hand thanks to direct transmission.
• the rotor is formed by a single multipolar ring.
• Such a one-piece construction is advantageous for the rotor because it does not require having to combine previously magnetized blocks of material, thus avoiding segment-by-segment assembly.
• the rotor is formed by a plurality of multipolar rings, that is to say at least 2.
• the rotor is formed by 2 or more multipolar rings that can be mounted axially one on the other, either simply glued together, or driven on the same cannulated shaft. This therefore has little effect on the assembly process, which is then carried out in segments; however, such a method of assembling several magnets axially makes it possible to create longer motors because there is a manufacturing constraint on the ratios of the dimensions of the magnets.
• This solution also makes it possible to reduce the current induced in the rotor, which goes in the direction of a reduction in losses (same concept as the lamination of the ferromagnetic parts).
• the rotor is formed by a magnetized plate of non-uniform thickness.
• the stator is of the slotted type.
• the volume of the stator is greater due to the presence of the teeth, and consequently the volume of the rotor is more limited and therefore the advantage conferred by the arrangement of a Halbach network even more relevant for maximizing the section of the hollow tubular part of the rotor potentially used as an internal suction channel while preserving engine efficiency.
• the present invention otherwise relates to a rotor for a rotary motor taken separately from the stator, characterized in that it comprises an outwardly biased Halbach network, this element being able to be produced and sold separately from the rest of the motor.
• FIG. 1 is a schematic view of a tool using a cannulated shaft as in the context of the present invention
• FIGS. 2A and 2B are schematic views respectively illustrating a solution using a Halbach network, as in the context of the present invention and a solution using a radial arrangement of magnets, without shielding;
• FIG. 3A and 3B respectively illustrate sectional views of a motor respectively using a radial arrangement of magnets and an internal shielding sheath, and on the contrary a Halbach network for the rotor.
• FIG. 4A and 4B illustrate variants respectively with and without slot (slotted and slotless) that can be used in the context of the present invention.
• micromotor according to the present invention, in which it is integrated into a microdebrider 1.
• FIG 1 is a schematic view of such a surgical tool, which is often referred to as a "shaver", aimed at eliminating or respectively removing material M such as soft tissue, via a rotary milling/grinding tool such as an abrasive blade 4, which here is directly coupled to a rotary motor 10 via a coupling device 14 such as for example a coupling nose (male element) introduced into an orifice of the blade (female element).
• the motor 10 is conventionally composed of a stator 12 arranged concentrically around a rotor 11, the hollow central tubular part of which is formed by a cannulated shaft 111, the inner wall 111 A of which constitutes a rectilinear duct corresponding to the suction channel 2 of the microdebrider.
• this duct consists of a material or a coating layer intended to facilitate the flow of a fluid sucked in by a pump 3 located behind a filter unit 5 where the waste material is evacuated in the direction of the arrow illustrated on the abrasive blade 4, and which corresponds to the path of the fluid and of the debris of material M sucked into the interior of the blade 4, which therefore itself also has a hollow shape.
• a pump 3 located behind a filter unit 5 where the waste material is evacuated in the direction of the arrow illustrated on the abrasive blade 4, and which corresponds to the path of the fluid and of the debris of material M sucked into the interior of the blade 4, which therefore itself also has a hollow shape.
• layers or a surface treatment rendering the internal wall 111 A hydrophobic according to a preferred embodiment, it is even possible to alternate hydrophilic and hydrophobic regions in order to separate the deposition of blood and/or of proteins removed or respectively torn off during the debriding operation, which will make it possible to facilitate the cleaning operations.
• the suction channel 2 is made of austenitic stainless steel, for example of 316L or 1.4301 type steel, in order to allow sterilization operations while avoiding any corrosion.
• the internal wall 111 A of the cannulated shaft 111 forming the suction channel 2 may preferably be coated with a polymer based on fluorides or with a thin layer of titanium oxide (Ti02) or other compounds. titanium chemicals in order to have an anti-microbial action.
• Ti02 titanium oxide
• the microdebrider 1 as illustrated in FIG. 1 has the advantage of not requiring any gear mechanism for the transmission of the rotation of the motor to the rotary milling tool, that is to say to the abrasive blade.
• the rotary motor 10 using an outwardly oriented Halbach network according to the invention makes it possible to have maximum efficiency while at the same time increasing the useful diameter of the suction channel 2, which constituted two parameters that could not be optimized simultaneously.
• Figures 2A and 2B make it possible to explain the operation of a Halbach network compared to a conventional magnetization solution.
• the magnetized system does not consist of 2 pairs of poles or several pairs, but of a combination of 'blocks' or 'zones' magnetized according to inclinations adapted to naturally cause the closing of the field lines without the need for the presence of soft ferromagnetic materials (soft steel, mu-metal).
• the Halbach array 61 uses a series of polarized magnets aimed at eliminating field lines inside the cylinder and doubling the field strength (arrows corresponding to magnetic field B doubled) compared to a conventional magnetization scheme with a radially polarized magnet 6, as illustrated in FIG.
• the outwardly biased Halbach 61 grating is made up of bipolar permanent magnets or multipolar permanent magnets.
• the rotor according to the invention can therefore be made, for example, according to one of the following embodiments:
• a rotor consisting exclusively of one or more permanent magnets
• a rotor consisting of a cannulated shaft made of diamagnetic, paramagnetic or 'weakly' ferromagnetic materials (magnetic permeability typically less than 100) located in the center of the rotor and extending in the axial direction, and one or more permanent magnets located outside the cannulated shaft. According to this embodiment, the permanent magnets are glued or driven onto the inner cannulated shaft.
• a rotor made up of one or more permanent magnets and a tube made of diamagnetic, paramagnetic or 'weakly' ferromagnetic materials (magnetic permeability typically less than 100) located outside of the set of permanent magnets. According to this embodiment, the permanent magnets are glued or driven into the outer tube.
• the rotor according to the invention has a percentage by mass of ferromagnetic material, permanently non-magnetized, preferably less than 10%.
• the rotor according to the invention has a percentage by mass of permanently magnetized ferromagnetic material, preferably greater than 70%.
• the maximum magnetic induction field at a distance of 2 mm from the outer surface of the rotor according to the invention, taken independently of the presence of a stator (that is to say for example for a rotor taken in isolation before assembly or on a spare part following a disassembly-reassembly operation) will preferably be greater than 0.1 T, and even more preferably between 0.2 and 0.3 T.
• Figures 3A and 3B illustrate how, in the context of the present invention, it is possible both to increase the diameter of the suction channel 2 and to increase the torque of the rotary motor thanks to the confinement of the magnetic field towards the periphery.
• the rotor 11 uses a radial arrangement of magnets 60 cooperating with the coils 121 of the stator 12 of which one can also see the lamination layers 122 of a segment.
• the rotor 11 is separated from the rotor by a gap, commonly called air gap 8, and inside it is formed a shielding layer 7 of ferromagnetic material.
• This thickness differential allows to increase by the same amount the diameter of the suction channel 2 located inside the rotor 111 and whose internal wall 111 A of the cannulated shaft that it forms, without however affecting the performance of the motor, given that the field lines redirected towards the exterior by the Halbach matrix 61 make it possible to densify the field lines at the periphery and consequently to proportionally increase the engine torque, and therefore the transmission efficiency.
• the inside diameter of the hollow central tubular part of the rotor according to the invention is preferably greater than 3 mm, and the motor torque is preferably between 10 and 100 mNm, according to a particularly preferred variant it is between 20 and 25 mNm. Thanks to such a configuration for the engine, it is now possible to jointly optimize these two previously antagonistic parameters and which therefore required a choice of prioritization.
• the rotor 111 can be formed by a single multipolar ring and thus be produced in an entirely one-piece configuration.
• it may be made by at least 2 multipolar rings driven onto the cannulated shaft 111 and also be made up of a plurality of magnetic plates of non-uniform thicknesses, in order to go into the direction of a reduction in losses according to the same concept as the lamination of the ferromagnetic parts of the stator 121, such as those corresponding to the elements 122 illustrated in FIGS. 3A and 3B.
• the multipolar ring on the basis of a magnetized plate of non-uniform thickness; in the case of a single ring, this may take the form of a fluted shape and in the case of a plurality of rings placed end-to-end according to an assembly segment by segment, the thicknesses may vary between the different segments, so to form a multi-stage cylinder with always the same objective of varying the field as continuously as possible along the cylinder, and thus to optimize the performance in terms of resulting torque for driving the rotor.
• FIGS. 4A and 4B illustrate two variants of stator which can be used within the framework of the present invention, that is to say which can cooperate with a rotor 11 in which a Halbach matrix is arranged.
• the stator 12 comprises lamination layers 122 and coils 121 cooperating with the rotor 11, preferably constituting a cannulated shaft at the center of which is arranged a suction channel 2.
• FIGS. 4A and 4B are only intended to describe two different types of stator 12, namely with or without slots (“slotted” or “slotless”) ).
• the rotor 11 is spaced with respect to the stator 12 by an air gap 8 towards the inside thereof.
• the yoke of the stator consists of a sheath in the form of a ring
• different series of coils are arranged in slots 124 located between teeth 123 of the stator.
• the slotted model is radially more voluminous, and consequently the use of a Halbach network for the rotor making it possible to recover this internal space trimmed by the stator 12 is all the more indicated - this is the reason why the size of the rotor 11 in Figure 4A has been intentionally shown to be substantially larger than that of Figure 4B.

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• Health & Medical Sciences (AREA)
• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Life Sciences & Earth Sciences (AREA)
• Surgery (AREA)
• Animal Behavior & Ethology (AREA)
• General Health & Medical Sciences (AREA)
• Veterinary Medicine (AREA)
• Public Health (AREA)
• Molecular Biology (AREA)
• Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
• Biomedical Technology (AREA)
• Medical Informatics (AREA)
• Heart & Thoracic Surgery (AREA)
• Orthopedic Medicine & Surgery (AREA)
• Oral & Maxillofacial Surgery (AREA)
• Dentistry (AREA)
• Epidemiology (AREA)
• Iron Core Of Rotating Electric Machines (AREA)
• Connection Of Motors, Electrical Generators, Mechanical Devices, And The Like (AREA)

Applications Claiming Priority (2)

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• 2021
  • 2021-07-07 CN CN202180048710.XA patent/CN115776872B/zh active Active
  • 2021-07-07 KR KR1020237000261A patent/KR102610075B1/ko active IP Right Grant
  • 2021-07-07 EP EP21743114.7A patent/EP4179611A1/de active Pending
  • 2021-07-07 WO PCT/EP2021/068894 patent/WO2022008618A1/fr unknown
  • 2021-07-07 US US18/013,004 patent/US11848587B2/en active Active

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