Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K5/00—Casings; Enclosures; Supports
  • H02K5/24—Casings; Enclosures; Supports specially adapted for suppression or reduction of noise or vibrations
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K5/00—Casings; Enclosures; Supports
  • H02K5/04—Casings or enclosures characterised by the shape, form or construction thereof
  • H02K5/20—Casings or enclosures characterised by the shape, form or construction thereof with channels or ducts for flow of cooling medium

Definitions

• the invention relates to an electric motor making it possible to reduce the noise pollution generated during its use.
• current electric motors include a rotor integral with a shaft and a stator which surrounds the rotor.
• the stator is mounted in a housing which has bearings for the rotational mounting of the shaft.
• the rotor comprises a body formed by a stack of sheets or pole wheels (claw pole) held in the form of a package by means of a suitable fixing system.
• the rotor body has internal cavities housing permanent magnets.
• the stator comprises a body formed by a stack of sheets forming a ring, the inner face of which is provided with teeth delimiting in pairs a plurality of notches open towards the interior of the stator body and intended to receive phase windings.
• phase windings pass through the notches of the stator body and form buns projecting on either side of the stator body.
• the phase windings can for example consist of a plurality of U-shaped conductor segments, the free ends of two adjacent segments being connected together by welding.
• the pack of sheets is clamped axially between a front flange and a rear flange mounted coaxially with the shaft.
• Each flange has the overall shape of a disc extending in a radial plane perpendicular to the axis of the shaft.
• Each flange comprises a central orifice for coaxial mounting on the shaft and several through holes intended to receive fixing screws axially passing through the entire package of sheets, said screws being secured to the flanges by means of nuts.
• the front and rear flanges are generally formed from a non-magnetic material which conducts heat, for example a metal.
• the housing usually has front and rear bearings assembled together.
• the bearings define an internal cavity in which the rotor and stator are housed.
• Each of the bearings centrally carries a ball bearing for the rotational mounting of the rotor shaft.
• noises can be of a mechanical nature and result from shocks or friction between the mechanical parts during the rotation of the rotor. They can also be magnetic and be generated by the magnetic forces produced by the currents flowing in the electric motor. Indeed, these magnetic forces can make vibrate the structure of the electric motor at audible frequencies (from 20 Hz to 20 kHz), and these vibrations are transmitted to the ambient air by the structure, generating noise.
• the solutions currently envisaged generally consist in optimizing the design or the material constituting the mechanical parts used in the engine so as to limit mechanical noise.
• these solutions do not make it possible to reduce magnetic noise.
• One of the aims of the invention is therefore to propose a solution to the problem of noise pollution generated by electric motors as described above, and, in particular, to propose a solution making it possible to reduce both mechanical noise and magnetic noise.
• the invention relates to an electric motor comprising a rotor mounted on a shaft, a stator arranged around the rotor, a front bearing and a rear bearing interconnected by fixing means, said front and rear bearings forming a cavity.
• internal housing in which the rotor and stator are housed the electric motor further comprising a bell-shaped soundproofing cover completely covering the rear bearing and a portion of the front bearing extending axially from an end face of said bearing front, the sound insulation cover being configured to dampen mechanical and magnetic noise generated by the motor.
• the electric motor will reduce the noise pollution generated during its use.
• the mechanical and magnetic noises generated by the motor will be absorbed by the soundproofing cover covering the rear bearing and part of the front bearing.
• the engine of the invention comprises one or more of the following optional characteristics considered alone or in combination:
• the soundproofing cover is made of plastic material.
• the material constituting the soundproofing cover is chosen from a silicone material, an inorganic polyurethane, a polyurethane-based foam, and a polyamide-based foam.
• the soundproofing cover consists of three layers, respectively a lower layer of plastic, an intermediate layer of fibrous material or foam, and an upper layer of plastic, foam or fibrous material.
• the soundproofing cover is in the form of a structure formed of three layers, namely two outer layers of plastic material and an inner layer of foam.
• the soundproofing cover is separated from the part of the front bearing extending axially by sealing elements.
• the sealing elements consist of annular seals housed at least partially inside annular grooves formed at the periphery of the part of the front bearing extending axially.
• the soundproofing cover forms with the front bearing at least one internal channel (9) for circulating liquid inside which circulates a cooling liquid.
• the internal liquid circulation channel has a substantially cylindrical shape, the axis of which is parallel to the axis defined by the rotor shaft.
• the soundproofing cover is equipped with at least one liquid inlet pipe and at least one liquid outlet pipe, said inlet and outlet pipes fluidly communicating with the internal liquid circulation channel .
• the front and rear bearings are made of metal.
• the front bearing is in aluminum and the rear bearing is in steel.
• the fixing means are screws.
• FIG. 1 is an exploded perspective view of an electric motor according to a particular embodiment of the invention
• FIG. 2 is a longitudinal sectional view of the engine of FIG. 1.
• Figures 1 and 2 show an electric motor 1 according to the invention comprising two parts, respectively a first part 10 and a second part 20, connected together, in particular by means of screws 21, the second part 20 housing and almost completely covering the first part 10.
• the first part 10 comprises a casing in which are housed a rotor 11 integral in rotation with a shaft 12 and an annular stator 13 which surrounds the rotor 11 coaxially with the shaft 12.
• the casing comprises in particular a front bearing 14 and a rear bearing 15 connected to each other by means of screws 16.
• the bearings 14, 15 are hollow in shape and each centrally carry a ball bearing 17 and 18 respectively for the rotational mounting of the shaft 12.
• Chignons 19 project axially on either side of the stator body 13 and are housed in the space intermediate separating the stator 13 from the respective bearings 14, 15.
• the front and rear bearings 14, 15 will advantageously be made of metal. In an advantageous configuration of the invention, the front bearing 14 will be made of aluminum, while the rear bearing 15 will be made of steel.
• the rotor 11 comprises a body formed by a bundle of sheets 2 made of a ferromagnetic material, in particular steel, as well as a plurality of permanent magnets 3 intended to be housed in a plurality of internal cavities. formed inside the packet of sheets 2, each internal cavity housing a permanent magnet 3.
• the packet of sheets 2 is mounted coaxially on the shaft 12 mounted to rotate around an X axis. force inside a central opening of the sheet metal pack 2 so as to rotate the rotor body with the shaft 12.
• the packet of sheets 2 is formed by an axial stack of sheets which extend in a radial plane perpendicular to the X axis of the shaft 12.
• a plurality of fixing holes are made in the packet of sheets. sheets 2 to allow the passage of fixing bolts 4 of the sheets of the package. These fixing holes are through so that it is possible to pass a bolt 4 inside each hole.
• a first end of the bolts 4 bears against the external face of a front end flange 5, while the other end of the bolts bears against the outer face of a rear end flange 6.
• the sheet metal pack 2 is clamped axially between the front end flange 5 and the rear end flange 6.
• flanges 5, 6 make it possible to ensure balancing of the rotor 11 while allowing good retention of the magnets 3 inside their respective cavity. Balancing can be done by adding or removing material. The material removal can be carried out by machining, while the addition of material can be carried out by implanting elements in openings provided for this purpose and distributed along the circumference of the flanges 5, 6.
• the second part 20 of the motor 1 consists of a bell-shaped cover which, in the mounted position of the motor shown in figure 2, completely covers the rear bearing 15 and a cylindrical part 142 of the front bearing 14 which extends axially from there. an end face 141 of said front bearing 14, said face 141 having the shape of a disc aligned in a plane perpendicular to the axis X of the shaft 12.
• the cover 20 rests at an end edge 24 on a shoulder 143 defined by the end face 141.
• the main function of the cover 20 is to attenuate the noises generated by the motor 1.
• it will advantageously be made of a plastic material. possessing increased sound absorption capacities.
• the cover 20 may advantageously be formed of a silicone material, of a polymer material based on inorganic polyurethane, of a polyurethane-based foam, of a polyamide-based foam. It may also have a complex structure formed of three layers, namely two outer layers of plastic material and an inner layer of foam. Thus configured, the cover 20 will make it possible to absorb the noises, both mechanical and magnetic, generated by the motor 1 during its operation.
• the cover 20 may consist of 3 layers, respectively a lower layer of plastic, an intermediate layer of fibrous material or foam, and an upper layer of plastic, foam or material. fibrous. This particular configuration will thus make it possible to define a mass - spring - mass system.
• the cover 20 has a shape substantially complementary to that of the cylindrical part 142 of the front bearing 14 so that, in the mounted position of the motor, this part 142 is in sealed contact with the internal wall 25 of the cover 20, the sealing being ensured by two seals 8 of annular shape which are housed inside two annular grooves 7 formed at the periphery of the part 142.
• the grooves 7 are arranged in on either side of an annular zone 144 of thinner part 142.
• the annular zone 144 forms with the internal wall 25 of the cover 20 an internal channel 9 for circulating liquid, said channel 9 having a substantially cylindrical shape. the axis of which is parallel to the axis X defined by the shaft 12 of the rotor 11.
• the channel 9 thus allows the circulation of a cooling liquid, such as for example water, glycol or an oil, around from ie cylindrical 142 of the bearing 14.
• a cooling liquid such as for example water, glycol or an oil
• the heat given off by the stator 13 and transmitted to the front bearing 14 can be directly transferred to the cooling liquid circulating in the internal channel 9.
• Faster cooling of the stator 13 can thus be obtained.
• the heat transfer to the coolant is further improved in the case where the front bearing 14 is made of a material having high thermal conductivity, such as aluminum for example, and the cover 20 is made of a material with high thermal conductivity. low thermal conductivity, such as a plastic for example.
• the cooling liquid will be supplied through a liquid inlet pipe 22 formed at the periphery of the cover 20, said inlet pipe 22 opening into the internal channel 9.
• the cooling liquid will exit. through a tubing of liquid outlet 23 formed at the periphery of cover 20, said outlet pipe 23 also opening into internal channel 9.
• the invention is obviously not limited to the configuration of the invention as described above.
• the internal diameter of the cover 20 may be greater than the external diameter of the part 142 of the front bearing 14.
• the internal channel 9 and the pipes inlet and outlet 22, 23 will be absent and the cooling of the stator 13 by means of a cooling liquid will not be ensured.

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• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Motor Or Generator Frames (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=70804757

Family Applications (1)

Country Status (3)

Family Cites Families (5)

• 2020
  • 2020-03-04 FR FR2002190A patent/FR3108001B1/fr active Active
• 2021
  • 2021-02-17 WO PCT/FR2021/050281 patent/WO2021176157A1/fr unknown
  • 2021-02-17 EP EP21711614.4A patent/EP4115506A1/de active Pending

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