JP5013751B2 - Electric motor - Google Patents

Description

  The present invention relates to an electric motor used as a spindle motor of a machine tool, and more particularly to cooling of the electric motor.

  As machine tool spindles rotate at high speed, many small and medium-sized machine tools have built-in motors that drive the spindle directly from the main spindle drive to a spindle unit driven by a separate motor. It can be seen.

  There are two types of built-in motors, one using a synchronous motor and the other using an induction motor. In the synchronous motor, the rotor (rotor) does not generate heat theoretically, but in addition to high cost, peeling of the permanent magnet on the rotor side by centrifugal force becomes a problem. For this reason, most of them are now based on induction motors.

  In the case of an induction motor, since current flows through the rotor and heat is generated, it is necessary to cool the rotor in addition to the stator.

  Built-in motor cooling can be classified into several categories. In an induction motor, the primary side (stator side) and the secondary loss (rotor loss) with large iron loss and copper loss are usually cooled separately. Cooling the primary side iron core part with cooling water (or oil) from the outside is almost established and not technically difficult. On the other hand, the secondary side rotates at high speed, and various measures have been proposed for secondary side cooling. The secondary side cooling is roughly classified into a method for liquid cooling the rotor (rotary main shaft) and a method for air cooling the rotor.

For example, compressed air is injected from one end into an axial through groove of a sleeve that fixes a rotor of a built-in motor to a main shaft, and the rotor is cooled by being put on the air flow in the through groove by fins at both ends of the sleeve. For example, Patent Document 1), there is one that injects a cooling liquid onto at least one of a stator, a rotor, and a spindle (for example, Patent Document 2).
JP-A-7-185994 JP-A-9-154257

  Since the method of liquid cooling the rotor (rotating main shaft) uses a heat medium having a large heat capacity, a large cooling effect can be expected. However, a device that delivers a liquid phase heat medium to a shaft that rotates at high speed, for example, a rotary joint, is required. The rotary joint has a limit on the upper limit of the rotational speed and has a short life.

On the other hand, the method of air-cooling the rotor can deliver the heat medium in a non-contact manner, and thus does not cause the limitation of the number of rotations and the problem of life as in the case of liquid cooling. However, depending on how to form a passage for air, become those cooling effect of the rotating element is significantly different.

  Normally, the annular gap formed between the outer periphery of the rotor and the inner circumference of the stator that is used as an air passage is narrow, and the air that follows the rotor rotating in the annular gap is between the yokes of the stator. Since it collides with the groove at a high speed and generates a high pressure, it is difficult for air to flow through the annular gap and a sufficient cooling effect cannot be expected.

  The problem to be solved by the present invention is to allow the rotor to be sufficiently cooled by air cooling.

An electric motor according to the present invention includes a rotor attached to a rotating shaft and provided with short-circuiting rings at both ends in the axial direction, and a stator attached to a motor housing, wherein the rotating shaft and the rotor outside circumference of the rotating shaft but to be fitted, provided a helical groove extending across the axial direction, fixed mounted to a portion of the rotary shaft adjacent to an end of the rotor, communicating with the spiral groove An annular ring having a groove, provided with an intake ring member having one end of the groove open to the outer peripheral surface, attached to a rotary shaft bracket fixedly attached to one end of the motor housing, and disposed on the outer periphery of the rotary shaft an inner member attached to the rotary shaft bracket is constituted by an outer annular member is disposed on the outer periphery of said inner member, an annular nozzle hole you open in the radial direction of the rotary shaft, the intake Li It provided to face at intervals at one end of the groove of the grayed member, characterized in that blowing air into one end of the groove of the intake ring member from the annular nozzle hole.

An electric motor according to the present invention includes a rotor attached to a rotating shaft and provided with short-circuiting rings at both ends in the axial direction, and a stator attached to a motor housing. A plurality of vent holes penetrating in the axial direction, one end of the plurality of vent holes communicating with a plurality of inlet holes opened on the outer peripheral surface of the one short-circuited ring, The other end of the motor is connected to a plurality of outlet holes opened on the outer peripheral surface of the other short-circuiting ring, and is attached to a rotary shaft bracket fixedly attached to one end of the motor housing, and is disposed on the outer periphery of the rotary shaft. and an annular inner member that is attached to the rotating shaft bracket is constituted by an outer annular member is disposed on the outer periphery of said inner member, an annular nozzle hole you open in a radial direction of said rotary shaft, said plurality Pieces It provided to face at a distance to the inlet hole, characterized in that blowing air into said plurality of inlet holes from the annular nozzle hole.

The electric motor according to the present invention includes an annular inner member that is attached to the rotating shaft bracket and is disposed on the outer periphery of the rotating shaft, and an annular outer member that is attached to the rotating shaft bracket and is disposed on the outer periphery of the inner member. , from the annular nozzle hole which opens in the radial direction of the rotary shaft, at one end of the groove of a suction ring member, or, from which blows air into a plurality of inlet holes of the short-circuit ring body, the air spiral groove or As a result , the rotor flows well and the rotor is cooled effectively.

  Embodiment 1 of an electric motor according to the present invention will be described with reference to FIG.

  The electric motor 10 is, for example, a spindle motor (built-in motor) of a machine tool, and is fixed to the cylindrical motor housing 11, the rotary shaft bracket 12 fixedly attached to one end of the motor housing 11, and the other end of the motor housing 11. The rear cover 13 is attached to form a cylindrical space-like motor chamber 14.

  A rotation shaft (rotor shaft) 15 is disposed at the center of the motor chamber 14 so as to be rotatable around its own central axis. A rotor 16 is fixedly mounted on the outer periphery of the rotating shaft 15. A cylindrical stator 21 is fixedly attached to the inner periphery of the motor housing 11. Both the rotor 16 and the stator 21 are in the motor chamber 14, and the rotor 16 is concentrically disposed inside the stator 21.

  The rotor 16 is provided with a rotor body 17 made of a laminated plate (silicon steel plate), a plurality of secondary conductor rods 18 penetrating the rotor body 17 in the axial direction, and a plurality of secondary conductor rods 18 provided at both left and right ends of the rotor body 17. The secondary conductor rod 18 is composed of short-circuited rings (end rings) 19 and 20 that are conductively connected to each other, and is fixedly attached to the rotary shaft 15 by shrink fitting or the like. The secondary conductor rods 18 are arranged at equal intervals around the central axis of the rotor 16 and have a predetermined skew angle for suppressing torque cogging.

  The stator 21 includes a stator body 22 made of a laminated plate and a stator coil 23 wound around the stator body 22. The winding 24 of the stator coil 23 is wound around a plurality of yokes 25 formed on the stator body 22 (see FIG. 2). The yokes 25 each extend in the axial direction, are provided at equal intervals in the circumferential direction of the stator body 22, and there are yoke grooves 26 between the adjacent yokes 25.

  The plurality of yoke grooves 26 may exist on the inner periphery of the stator main body 22 and may be inclined with respect to the generatrix direction of the stator outer periphery with a predetermined skew angle.

  An annular gap (air gap) 27 is formed between the outer periphery of the rotor body 17 and the inner periphery of the stator body 22 having the yoke grooves 26. The annular gap 27 is desirably small in order to minimize the magnetic loss of the electric motor 10.

  A stator cooling sleeve 31 is mounted on the outer periphery of the motor housing 11. A spiral groove is formed on the inner periphery of the stator cooling sleeve 31 and cooperates with the outer periphery of the motor housing 11 to define a spiral cooling water passage 32. The stator cooling sleeve 31 is formed with a cooling water inlet 33 communicating with one end of the cooling water passage 32 and a cooling water outlet 34 communicating with the other end of the cooling water passage 32.

  Thereby, cooling water enters the cooling water passage 32 from the cooling water inlet 33, and the cooling water flows through the cooling water passage 32, while cooling the stator body 22 from the outside via the motor housing 11. The cooling water that has flowed through the cooling water passage 32 finishes cooling the stator body 22 and is discharged to the outside from the cooling water outlet 34.

An air nozzle 41 is provided on the rotating shaft bracket 12 side in the motor chamber 14. Air nozzle 41 is constituted by an annular outer member 42 and inner member 43, constitute a ring-shaped nozzle hole 44 in the outer member 42 and inner member 43. The annular injection hole 44 is at the tip of the flange-shaped portion of the outer member 42 and the inner member 43 and opens in the axial direction, is concentric with the annular gap 27, and has the same diameter as one opening end 27 </ b> A in the axial direction of the annular gap 27. It faces the opening end 27A with a small gap in the direction position.

  The annular injection hole 44 communicates with an air inlet 48 formed in the rotary shaft bracket 12 by air passages 45 and 46 formed in the outer member 42 and the inner member 43 and an air passage 47 formed in the rotary shaft bracket 12. is doing.

  The air nozzle 41 is supplied with compressed air (pressurized air) from the air inlet 48 and ejects air from the annular injection hole 44 toward the annular gap 27. The air ejected from the annular nozzle 44 toward the annular gap 27 enters the annular gap 27 from one open end 27A of the annular gap 27 and flows in the annular gap 27 as an axial air flow. 16 and the stator 21 are cooled. The air flowing through the annular gap 27 flows out of the annular gap 27 from the other opening end 27B in the axial direction of the annular gap 27 and is discharged out of the motor chamber 14 through the exhaust hole 29 formed in the rear cover 13.

  As described above, the compressed air blows out from the annular nozzle hole 44 of the air nozzle 41 opened toward the opening end 27A of the annular gap 27, so that even if the compressed air is at a relatively low pressure, the annular gap is generated by the jet flow velocity energy. 27 flows directly into the air gap 27 and flows favorably in the annular gap 27 as an axial air flow.

  If the yoke groove 26 of the stator 21 is inclined with respect to the generatrix direction of the outer periphery of the stator with a predetermined skew angle, a screw pump action is generated in the annular gap 27 as the rotor 16 rotates, and the annular gap 27 The axial air flow inside becomes stronger and better.

  For these reasons, even if the compressed air blown out from the annular injection hole 44 is at a low pressure, the air cooling of the rotor 16 and the stator 21 is efficiently performed by the axial air flow that flows favorably in the annular gap 27. In addition, since high air pressure is not required, the compressed air jetted from the annular nozzle hole 44 toward the annular gap 27 lubricates the bearings of the rotary shaft 15 provided before and after the rotor 16 (air oil lubrication, oil mist lubrication). , Grease lubrication) is not adversely affected.

  Note that the compressed air blown out from the annular nozzle hole 44 may be temperature-controlled, and the rotor 16 is fixed when the air temperature of the axial airflow flowing through the annular gap 27 is low. The child 21 is air-cooled better.

  The axial gap a between the flange tip surface of the air nozzle 41 having the annular nozzle hole 44 and the end surfaces of the rotor body 17 and the stator body 22 facing the flange tip surface parallel to the flange tip surface is set to a minimum necessary small value. An axial non-contact type seal is formed between the end surface of the air nozzle 41 and the end surfaces of the rotor body 17 and the stator body 22. Thereby, the air loss in the air delivery part between the air nozzle 41 and the annular space | gap 27 is stopped to the minimum, and useless air consumption is reduced.

In this embodiment, an extended cooling water passage 49 is formed in the outer member 42 of the air nozzle 41. Expansion cooling water passage 49, the communication hole 50 formed in the stator cooling sleeve 31 in one communicates with the cooling water passage (upstream side) 32, the cooling water passage by communicating hole 51 formed in the stator cooling sleeve 31 at the other The cooling water communicates with the (downstream side) 32 and the cooling water from the cooling water inlet 33 is diverted.

  Thereby, the cooling water flows through the extended cooling water passage 49, and the outer member 42 is cooled. The outer surface 42A on the stator 21 side of the outer member 42 is located close to the end of the stator coil 23, and cools the stator coil 23 by radiation. The cooling effect of the stator coil 23 by the cooling water flowing through the extended cooling water passage 49 is preferably such that the outer member 42 has good heat transfer and good radiation heat absorption. Therefore, the outer member 42 is made of a copper alloy or the like, and the outer surface 42A is subjected to a black matte surface treatment. Further, the outer surface 42A of the outer member 42 on the stator 21 side is expanded in surface area by grooving or the like, so that the cooling effect of the stator coil 23 is improved.

  FIG. 3 shows a first modification of the electric motor according to the first embodiment. 3, parts corresponding to those in FIG. 1 are denoted by the same reference numerals as those in FIG. 1, and description thereof is omitted.

  In this embodiment, circumferential grooves (annular grooves) 52 and 53 are formed on the outer periphery of one end of the rotor body 17 and the inner periphery of one end of the stator body 22, respectively.

  The distal end side of the flange-shaped portion of the outer member 42 and the inner member 43 of the air nozzle 41 enters the circumferential grooves 52 and 53, and the annular injection hole 44 is concentric with the annular gap 27 in the circumferential grooves 52 and 53. Thus, a small axial gap b is provided at the same radial position at one opening end 27A in the axial direction of the annular gap 27 and faces the opening end 27A.

  There is a small radial gap c in the radial direction between the outer member 42 and the flange portion of the inner member 43 and the circumferential grooves 52 and 53. The radial gap c is set to a necessary minimum value, and a radial non-contact seal is formed between the flange-shaped portion of the air nozzle 41 and the rotor body 17 and the stator body 22. Thereby, also in this embodiment, the air loss in the air delivery part between the air nozzle 41 and the annular gap 27 is minimized, and wasteful air consumption is reduced.

  The modification 1 shown in FIG. 3 differs from the first embodiment shown in FIG. 1 only in the type of the non-contact type seal in the air delivery section described above. Same as 1. Therefore, also in this modification, the same effect as that of the first embodiment shown in FIG. 1 can be obtained.

FIG. 4 shows a second modification of the electric motor according to the first embodiment. 4 , parts corresponding to those in FIG. 1 are denoted by the same reference numerals as those in FIG. 1, and description thereof is omitted.

  In the second modification shown in FIG. 4, in addition to the configuration of the first embodiment, a plurality of rotor bodies 17 extending across the axial direction on the outer peripheral surface of the rotor body 17 each with a predetermined skew angle. The ventilation groove 35 is formed.

  The ventilation groove 35 having a skew angle causes a screw pump action in the annular gap 27 as the rotor 16 rotates, and the axial air flow in the annular gap 27 becomes stronger and better. The stator 21 is air-cooled more efficiently.

  Note that the air nozzle 41 can be omitted if a sufficient axial air flow is generated in the annular gap 27 by the screw pump action of the ventilation groove 35.

  A second embodiment of the electric motor according to the present invention will be described with reference to FIG. In FIG. 5 as well, portions corresponding to those in FIG. 1 are denoted by the same reference numerals as those in FIG. 1, and description thereof is omitted.

  In the second embodiment, the air nozzle 61 that blows air into the annular gap 27 includes a nozzle pipe 62 that is installed so as to penetrate the axial middle portion of the stator body 22 in the radial direction. There are four nozzle tubes 62 at a plurality of positions in the circumferential direction of the stator body 22, for example, at a rotation angle position of 90 degrees, and each has a circular hole 63 that opens into the annular gap 27.

  Each nozzle pipe 62 communicates with an air inlet 66 formed in the stator cooling sleeve 31 by a communication hole 64 formed in the motor housing 11 and a circumferential groove (annular groove) 65 formed in the stator cooling sleeve 31. Yes.

Each nozzle pipe 62 is supplied with compressed air (pressurized air) from an air inlet 65, and ejects air from an injection hole 63 to an intermediate portion in the axial direction of the annular gap 27. Almost half of the air jetted from the nozzle hole 63 to the intermediate portion in the axial direction of the annular gap 27 flows into the opening end 27A as an axial air flow in the annular gap 27, and the rotor 16 and the stator 21 are passed between them. cooling the remainder flows to the opposite side of the opening end 27B and the open end 27A of the annular gap 27 as axial air flow, respectively, during which cooling the rotor 16 and stator 21.

  The air flowing through the annular gap 27 flows out of the annular gap 27 from each of the open ends 27A and 27B of the annular gap 27, and the exhaust holes 28 formed in the motor housing 11 and the exhaust holes 29 formed in the rear cover 13 are discharged. Each is discharged out of the motor chamber 14.

  As described above, the compressed air is relatively low in pressure because the compressed air is blown directly from the nozzle hole 63 of the air nozzle 61 opened in the axial direction intermediate portion of the annular gap 27 to the axial direction intermediate portion of the annular gap 27. However, it flows directly into the annular gap 27 and flows favorably in the annular gap 27 as an axial air flow.

  Thereby, even if the compressed air which blows off from the nozzle hole 63 is a low pressure, the air cooling of the rotor 16 and the stator 21 is efficiently performed by the axial airflow which flows favorably in the annular gap 27. Moreover, since high air pressure is not required, the compressed air that is jetted from the nozzle hole 63 toward the annular gap 27 is used to lubricate the bearings of the rotary shaft 15 provided before and after the rotor 16 (air oil lubrication, oil mist lubrication, (Grease lubrication) is not adversely affected.

  Embodiment 3 of the electric motor according to the present invention will be described with reference to FIG. In FIG. 6 as well, portions corresponding to those in FIG. 1 are denoted by the same reference numerals as those in FIG. 1, and description thereof is omitted.

  In the third embodiment, a spiral groove 71 is formed on the outer periphery of a portion where the rotary shaft 15 is fitted to the rotor 16 as a groove extending across the fitting portion in the axial direction. In this embodiment, two spiral grooves 71 are provided with a rotational direction phase difference of 180 degrees.

  An air supply ring member 72 is concentrically fixedly attached to a portion where the rotating shaft 15 is adjacent to one end of the rotor 16 (end on the rotating shaft bracket 12 side). An air supply ring member 72 forming a part of the rotary shaft 15 includes a circumferential groove (annular groove) 73, and one end 71 </ b> A of the circumferential groove 73 and the spiral groove 71 provided for each spiral groove 71. A communicating axial groove 74 is formed.

  The surface of each of the spiral groove 71, the circumferential groove 73, and the axial groove 74 is subjected to surface treatment with good heat transfer by copper plating, thermal spray of good heat transfer metal, or the like. In the case of thermal spraying of a highly heat conductive metal, it is preferable to use a material having large spray particles in order to increase the surface area.

  An air nozzle 81 is provided on the rotating shaft bracket 12 side in the motor chamber 14. The air nozzle 81 is constituted by an annular outer member 82 and an inner member 83, and constitutes an annular injection hole 84 formed by the outer member 82 and the inner member 83. The annular injection hole 84 is at the tip of the flange-shaped portion of the outer member 82 and the inner member 83 and opens in the radial direction, is concentric with the air supply ring member 72, and has the same axial direction as the circumferential groove 73 of the air supply ring member 72. It faces the circumferential groove 73 at a position with a small gap.

  The annular injection hole 84 communicates with the air inlet 48 of the rotary shaft bracket 12 by the air passages 85 and 86 formed in the outer member 82 and the inner member 83 and the air passage 47 formed in the rotary shaft bracket 12.

  The air nozzle 81 is supplied with compressed air (pressurized air) from the air inlet 48 and ejects air from the annular injection hole 84 toward the circumferential groove 73 of the air supply ring member 72. The air ejected from the annular nozzle 84 toward the circumferential groove 73 of the air supply ring member 72 passes through the axial groove 46 from the circumferential groove 73 and enters the spiral groove 71 from one end 71A of the spiral groove 71. , Flows in the spiral groove 71, during which the rotor 16 is cooled. The air flowing through the spiral groove 71 flows out of the spiral groove 71 from the other end 71B in the axial direction of the spiral groove 71 and is discharged out of the motor chamber 14 through the exhaust hole 29 formed in the rear cover 13.

  As described above, the compressed air blows out from the annular nozzle hole 84 of the air nozzle 81 opened toward the circumferential groove 73 of the air supply ring member 72 that communicates directly with the spiral groove 71, so that the compressed air is compared. Even if the pressure is low, it flows into the circumferential groove 73 due to the jet flow velocity energy, and then enters the spiral groove 71 through the axial concave groove 74, and flows well in the spiral groove 71 as an air flow.

  Thereby, even if the compressed air which blows off from the annular injection hole 84 is a low pressure, the air cooling of the rotor 16 is efficiently performed by the air flow which flows favorably in the spiral groove 71. In addition, since high air pressure is not required, the compressed air ejected from the annular nozzle hole 84 adversely affects the lubrication performance (air oil lubrication, oil mist lubrication, grease lubrication) of the bearings of the rotating shaft 15 provided before and after the rotor 16. Never give.

  Note that the compressed air blown out from the annular nozzle 84 may be temperature-controlled, and the air temperature of the axial airflow flowing through the spiral groove 71 is low, so that the air cooling of the rotor 16 is performed. Is better done.

  The radial gap d between the heel tip surface of the air nozzle 81 having the annular nozzle hole 84 and the outer peripheral surface of the air supply ring member 72 facing the heel tip surface is set to a minimum necessary small value. A radial non-contact type seal is formed between the heel end surface of the nozzle 81 and the outer peripheral surface of the air supply ring member 72. Thereby, the air loss in the air delivery part between the air nozzle 81 and the air supply ring member 72 is minimized, and wasteful air consumption is reduced.

  In addition, in the air delivery part between the air nozzle 81 and the air supply ring member 72, in order to comprise a non-contact-type seal | sticker with little air loss, the axial between the collar part of the air nozzle 81 and the short circuit ring 19 is provided. The radial gap f between the gap e and the air supply ring member 72 short-circuit ring body 19 is also set to a necessary minimum value.

In this embodiment, an extended cooling water passage 87 is formed in the outer member 82 of the air nozzle 81. Expansion cooling water passage 87, the communication hole 50 formed in the stator cooling sleeve 31 in one communicates with the cooling water passage (upstream side) 32, the cooling water passage by communicating hole 51 formed in the stator cooling sleeve 31 at the other The cooling water communicates with the (downstream side) 32 and the cooling water from the cooling water inlet 33 is diverted.

Thereby, the cooling water flows through the extended cooling water passage 87, and the outer member 82 is cooled. The outer surface 82A on the stator 21 side of the outer member 82 is located close to the end of the stator coil 23, and cools the stator coil 23 by radiation. The cooling effect of the stator coil 23 by the cooling water flowing through the extended cooling water passage 87 is preferably such that the outer member 82 has good heat transfer properties and good radiation heat absorption properties. Therefore, the outer member 82 is made of a copper alloy or the like, and the outer surface 82A is subjected to a black matte surface treatment. Further, the outer surface 82A of the outer member 82 on the stator 21 side can be improved in the cooling effect of the stator coil 23 by expanding the surface area by grooving or the like, as in the first embodiment.

  Embodiment 4 of the electric motor according to the present invention will be described with reference to FIGS. In FIG. 7 as well, portions corresponding to those in FIG. 1 are denoted by the same reference numerals as those in FIG. 1, and description thereof is omitted.

  In the fourth embodiment, the rotor 16 is formed with a plurality of air holes 91 penetrating the rotor body 17 in the axial direction. The air holes 91 are arranged at equal intervals around the central axis of the rotor 16 and have the same skew angle as that of the secondary conductor rod 18 in order to avoid interference with the secondary conductor rod 18. Each of the vent holes 91 is formed in the short-circuit ring body 19 at one end and communicates with an inlet hole 92 that opens to the outer peripheral surface of the short-circuit ring body 19, and is formed in the short-circuit ring body 20 at the other end. It communicates with an outlet hole 93 that opens to the outer peripheral surface.

An air nozzle 101 is provided on the rotating shaft bracket 12 side in the motor chamber 14. Air nozzle 101 is constituted by an annular outer member 102 and inner member 103 constitute a ring-like injection hole 104, and an outer member 102 and inner member 103. The annular injection hole 104 is at the distal end of the flange-shaped portion of the outer member 102 and the inner member 103 and opens in the radial direction. The annular injection hole 104 is concentric with the short-circuiting ring 19 and is located at the same axial position as the inlet hole 92. Opposite with a small gap.

  The annular injection hole 104 communicates with an air inlet 48 of the rotary shaft bracket 12 by air passages 105 and 106 formed in the outer member 102 and the inner member 103 and an air passage 47 formed in the rotary shaft bracket 12.

  The air nozzle 101 is supplied with compressed air (pressurized air) from the air inlet 48, and ejects air from the annular injection hole 104 toward the outer peripheral surface of the short-circuit ring body 19. The air jetted from the annular injection hole 104 toward the outer peripheral surface of the short-circuiting ring body 19 enters the ventilation hole 91 through the inlet hole 92 opened on the outer peripheral surface of the short-circuiting ring body 19, and flows in the ventilation hole 91. In the meantime, the rotor 16 is cooled. The air that has flowed through the vent hole 91 flows out of the vent hole 91 through the outlet hole 93 of the short-circuit ring body 20 on the side opposite to the short-circuit ring body 19 and out of the motor chamber 14 through the exhaust hole 29 formed in the rear cover 13. Discharged.

  As described above, the compressed air is blown out from the annular injection hole 104 of the air nozzle 101 opened toward the inlet hole 92 of the short-circuit ring body 19 that communicates directly with the vent hole 91, so that the compressed air is at a relatively low pressure. Even if it exists, it will flow in into the inlet hole 92 with injection | spray flow velocity energy, and will enter into the ventilation hole 91 more favorably from this, and the inside of the ventilation hole 91 will flow favorably as an air flow.

Thereby, even if the compressed air blown out from the annular injection hole 104 is at a low pressure, the air flow that favorably flows through the ventilation hole 91 allows the rotor 16 to be cooled more efficiently than the inside of the rotor 16 (heat-generating high-temperature part). Is called. Moreover, since high air pressure is not required, the compressed air ejected from the annular nozzle hole 104 adversely affects the lubrication performance (air oil lubrication, oil mist lubrication, grease lubrication) of the bearings of the rotating shaft 15 provided before and after the rotor 16. Never give.

  The compressed air blown out from the annular nozzle 104 may be temperature-controlled, and the air temperature of the axial flow of air flowing through the vent hole 91 is low, so that the air cooling of the rotor 16 is performed. Is better done.

A beak tip surface of the air nozzle 101 having an annular nozzle hole 104, radial clearance g between the outer peripheral surface of the short-circuit ring 19 to face the beak tip surface is set to a necessary minimum small value, the air nozzle 101 A radial non-contact type seal is formed between the heel tip surface and the outer peripheral surface of the short-circuit ring body 19. Thereby, the air loss in the air delivery part between the air nozzle 101 and the inlet hole 92 is minimized, and wasteful air consumption is reduced.

  The inlet hole 92 of the short-circuit ring body 19 and the outlet hole 93 of the short-circuit ring body 20 may be opened at the end faces of the short-circuit ring bodies 19 and 20, respectively, as shown in FIG. In this case, the annular nozzle hole 104 of the air nozzle 101 opens in the axial direction and faces the inlet hole 92 with a small gap at the same radial position as the inlet hole 92.

  Also in this case, the compressed air blows out from the annular nozzle 104 of the air nozzle 101 opened toward the inlet hole 92 of the short-circuiting ring 19 that communicates directly with the vent hole 91, so that the compressed air is at a relatively low pressure. Even if it exists, it flows into the inlet hole 92 due to the jet flow velocity energy, enters into the vent hole 91 better from this, flows well in the vent hole 91 as an air flow, and the compressed air blown out from the annular nozzle hole 104 has a low pressure. Even in this case, the air cooling of the rotor 16 is efficiently performed by the air flow that favorably flows through the vent hole 91.

In addition, the axial gap h between the heel tip surface of the air nozzle 101 having the annular nozzle hole 104 and the end surface of the short-circuit ring body 19 facing the heel tip surface is set to a minimum necessary small value. An axial non-contact seal is formed between the end face of the flange 101 and the end face of the short ring 19. Thereby, the air loss in the air delivery part between the air nozzle 101 and the inlet hole 92 is minimized, and wasteful air consumption is reduced.

It is sectional drawing which shows Embodiment 1 of the electric motor by this invention. FIG. 3 is a partial enlarged cross-sectional view of the stator of the electric motor according to the first embodiment. It is sectional drawing which shows the modification 1 of Embodiment 1 of the electric motor by this invention. It is sectional drawing which shows the modification 2 of Embodiment 1 of the electric motor by this invention. It is sectional drawing which shows Embodiment 2 of the electric motor by this invention. It is sectional drawing which shows Embodiment 3 of the electric motor by this invention. It is sectional drawing which shows Embodiment 4 of the electric motor by this invention. It is sectional drawing along line IIX-IIX of FIG. It is sectional drawing which shows the modification of Embodiment 4 of the electric motor by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Electric motor 11 Motor housing 12 Rotating shaft bracket 13 Rear cover 14 Motor chamber 15 Rotating shaft 16 Rotor 17 Rotor main body 18 Secondary conductor rod 19, 20 Short-circuiting ring 21 Stator 22 Stator main body 23 Stator coil 24 Winding 25 Yoke 26 Yoke Groove 27 Annular gap 27A, 27B Open end 29 Exhaust hole 31 Stator cooling sleeve 32 Cooling water passage 33 Cooling water inlet 34 Cooling water outlet 35 Ventilation groove 41 Air nozzle 42 Outer member 42A Outer surface 43 Inner member 44 Annular nozzle 45, 46 , 47 Air passage 48 Air inlet 49 Extended cooling water passage 50, 51 Communication hole 52, 53 Circumferential groove 61 Air nozzle 62 Nozzle pipe 63 Injection hole 64 Communication hole 65 Circumferential groove 66 Air inlet 71 Spiral groove 71A, 71B End 72 Supply Air ring member 73 Circumferential groove 74 Axis Recessed groove 81 Air nozzle 82 Outer member 82A Outer surface 83 Inner member 84 Annular injection hole 85, 86 Air passage 87 Extended cooling water passage 91 Ventilation hole 92 Inlet hole 93 Outlet hole 101 Air nozzle 102 Outer member 103 Inner member 104 Annular injection Hole 105, 106 Air passage a, b, e, h Axial gap c, d, f, g Radial gap

Claims (2)

In an electric motor having a rotor attached to a rotating shaft and provided with a short-circuit ring at both ends in the axial direction, and a stator attached to a motor housing,
Provided on the outer periphery of the rotating shaft with which the rotating shaft and the rotor are fitted, a spiral groove extending across the axial direction;
An inlet ring member is provided that is fixedly attached to a portion of the rotating shaft adjacent to the end of the rotor, has a groove communicating with the spiral groove, and one end of the groove opens to the outer peripheral surface;
An annular inner member that is attached to a rotating shaft bracket fixedly attached to one end of the motor housing and disposed on the outer periphery of the rotating shaft, and an annular member that is attached to the rotating shaft bracket and disposed on the outer periphery of the inner member. of which is constituted by an outer member, an annular nozzle hole you open in the radial direction of the rotary shaft, provided at a gap is opposed to one end of the groove of the intake ring member,
Air is blown into one end of the groove of the intake ring member from the annular injection hole,
An electric motor characterized by that. In an electric motor having a rotor attached to a rotating shaft and provided with a short-circuit ring at both ends in the axial direction, and a stator attached to a motor housing,
Before SL rotor, it provided a plurality of vent holes through the rotor in the axial direction,
One end of the plurality of vent holes communicates with a plurality of inlet holes opened on the outer peripheral surface of the one short-circuited ring,
The other end of the plurality of vent holes communicates with a plurality of outlet holes opened on the outer peripheral surface of the other short-circuit ring body,
An annular inner member that is attached to a rotating shaft bracket fixedly attached to one end of the motor housing and disposed on the outer periphery of the rotating shaft, and an annular member that is attached to the rotating shaft bracket and disposed on the outer periphery of the inner member. of which is constituted by an outer member, an annular nozzle hole you open in the radial direction of the rotary shaft, provided to face at a gap to the plurality of inlet holes,
Air is blown into the plurality of inlet holes from the annular nozzle hole ,
An electric motor characterized by that .

Images