JP2010041853A - Electric motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric motor that reliably prevents the entry of water into a bearing by doubly providing a labyrinth, and to enhance low noise capability and durability. <P>SOLUTION: A coil 17 is wound on multiple teeth 13 of a stator base 4 to construct a stator S. A rotor R is constructed of: a closed-end cylindrical rotor yoke 60 that covers the stator S from front; and a magnet 62 placed on the peripheral wall 61 of the rotor yoke 60 in correspondence with the coil 17. A rotating shaft 6 provided in the central part of the rotor R is rotatably supported in the central part of the stator base 4 through a first bearing 29 and a second bearing 30. At least a first labyrinth 94 and a second labyrinth 99 are provided in the areas extended from between the open edge 70 of the rotor yoke 60 and the stator base 4 to the first bearing 29 and the second bearing 30. At least the first labyrinth 94 is provided in the ring 92 of the stator S and is formed of a protrusion 93. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electric motor for driving a cooling fan in which a fan blade is fixed to an outer rotor, for example.

  Conventionally, an outer rotor type electric brushless motor is sometimes used as a fan motor for cooling a radiator of an automobile. In this type of electric motor, a stator is formed by winding a coil around a plurality of teeth provided on a stator base, and the rotor is composed of a bottomed cylindrical rotor yoke and a permanent magnet disposed on the inner peripheral surface of the rotor yoke. And the rotating shaft of the rotor yoke is rotatably supported on the stator base. Fan blades are provided on the outer periphery of the rotor yoke. When current is supplied to the coil, a magnetic field is formed in the stator teeth, and a magnetic attraction force or repulsive force is generated between the rotor yoke and the rotor magnet, causing the rotor to rotate. The cooling air is generated in the axial direction of the rotary shaft by the fan blade.

In this type of electric motor, since the rotor as a rotor rotates outside the stator as a stator, the rotor covers the stator in an automobile radiator that is often used in a wet environment. Such a structure is adopted, and it has a structure that prevents water from entering inside.
For example, in order to ensure water tightness, a labyrinth structure is formed by a protective wall protruding from the rotor side and a flange protruding from the stator side so that water does not enter from a gap formed between the rotor and the stator, Some have water prevented entry (see, for example, Patent Document 1).
JP 2007-53844 A

  However, in the above-described prior art, water that has entered from between the rotor and the stator once passes through the labyrinth portion and enters the interior, and the intruded water reaches the bearing portion and causes the lubricant in the bearing portion to flow out. In such a case, there is a problem that the lubrication performance of the bearing portion is affected and the sound vibration and durability are deteriorated.

  Accordingly, an object of the present invention is to provide an electric motor that can reliably suppress the intrusion of water into the bearing portion by providing a double labyrinth portion, and can improve sound vibration and durability.

  In order to achieve the above object, the invention described in claim 1 is directed to a plurality of teeth (for example, the teeth 13 in the embodiment) provided on a stator base (for example, the stator base 4 in the embodiment) to coils (for example, the teeth). A coil 17) in the embodiment is wound to form a stator (for example, the stator S in the embodiment), and a bottomed cylindrical rotor yoke (for example, the rotor yoke 60 in the embodiment) that covers the stator from its front surface, and this A rotor (for example, the rotor R in the embodiment) is constituted by a permanent magnet (for example, the magnet 62 in the embodiment) arranged on the inner peripheral surface of the rotor yoke (for example, the peripheral wall 61 in the embodiment), and the central portion of the rotor Is provided with a rotating shaft (for example, the rotating shaft 6 in the embodiment), and this rotating shaft is connected to the stator. An electric motor rotatably supported by a central portion of the sleeve via bearings (for example, the first bearing 29 and the second bearing 30 in the embodiment), and an opening edge of the rotor yoke (for example, an opening edge in the embodiment) 70) and at least two labyrinth portions (for example, the labyrinth portion 94 and the labyrinth portion 99 in the embodiment) are provided in a portion from between the stator base and the bearing, and at least one labyrinth portion is provided on the stator base. And provided on a ring portion (for example, the ring portion 92 in the embodiment) close to the inside of the peripheral wall of the rotor yoke, and further formed by a ridge (for example, the ridge 93 in the embodiment).

  According to a second aspect of the present invention, one of the two labyrinth portions is a first labyrinth portion (for example, the labyrinth portion in the embodiment) formed between the opening edge of the rotor yoke and the front surface of the stator base. 94), and the other one is a second labyrinth part (for example, the labyrinth in the embodiment) formed immediately before the bearing and formed between the bearing holder (for example, the bearing holder 27 in the embodiment) and the rotor yoke. Part 99).

  According to a third aspect of the present invention, the first labyrinth portion includes a ring portion (for example, the ring portion 92 in the embodiment) that is provided on the stator base and is close to the inside of the peripheral wall of the rotor yoke, and an opening edge of the rotor yoke. It is characterized by being formed between.

  According to a fourth aspect of the present invention, the first labyrinth portion includes an annular groove (for example, the grooves 95 and 95 ′ in the embodiment) provided in a portion of the stator base facing the opening edge of the rotor yoke. The rotor yoke is formed between the opening edge of the rotor yoke (for example, the terminal portions 70a and 70a ′ in the embodiment) provided in the groove.

  According to a fifth aspect of the present invention, the second labyrinth portion includes a flange-shaped water shield ring portion (for example, the water shield ring portion 35 in the embodiment) extending outside the bearing holder, and the water shield ring portion. And a ring-shaped member (for example, the inner ring portion 82 in the embodiment) extending along the rotation axis from the bottom wall of the rotor yoke (for example, the bottom wall 63 in the embodiment) near the outside of the rotor yoke. Features.

According to the first aspect of the present invention, even if water enters the interior from between the opening edge of the rotor yoke and the stator base, the water enters the bearing by at least two labyrinth portions provided in the path leading to the bearing. Therefore, it is possible to prevent the lubricant from flowing out of the bearing, maintain the lubrication performance of the bearing, and improve sound vibration and durability.
Moreover, since at least one labyrinth part is formed in the ring part of the stator, it becomes possible to trap water in the stator ring part. Here, the stator is warmed by the heat generated by the electric motor. However, since water is trapped in the ring portion, the cooling performance of the stator can be improved by the specific heat of the trapped water and its heat of vaporization.
According to the second aspect of the present invention, first, the first labyrinth portion suppresses the intrusion of water from between the opening edge of the rotor yoke where the water starts to enter and the front surface of the stator base, and the bearing Immediately before, the second labyrinth portion can reliably prevent water from entering the bearing.
According to the invention described in claim 3, it is possible to secure the length of the water intrusion path so as to go around between the ring portion and the inner side of the peripheral wall of the rotor yoke, and to further suppress the ingress of water into the inside. .
According to the fourth aspect of the present invention, the water is provided so as to go around between the annular groove provided in the portion of the stator base facing the opening edge of the rotor yoke and the opening edge of the rotor yoke provided adjacent to the groove. The length of the intrusion path can be secured, and the intrusion of water into the interior immediately before the bearing can be suppressed.
According to the fifth aspect of the present invention, the second labyrinth portion formed by the water shield ring portion provided around the bearing holder for holding the bearing and the ring-shaped member extending from the bottom wall of the rotor yoke is immediately before the bearing. Thus, it is possible to reliably prevent water from entering the bearing.

Next, embodiments of the present invention will be described with reference to the drawings. In the following description, the left side of FIG. 1 is the front side, and the right side of FIG. 1 is the rear side.
1 to 3, reference numeral 1 denotes a fan motor. The fan motor 1 is for cooling an automobile radiator. The fan motor 1 includes a brushless type electric motor M and a fan blade 3 supported by a rotor R of the electric motor M. The rotor R is an outer rotor type, and a stator S is provided in the rotor R. The stator base 4 of the stator S is attached to the fan shroud 91.
The stator base 4 is made of aluminum and is provided with three mounting pieces 5 attached to the radiator. In the central portion of the rear surface of the stator base 4, a housing portion 9 for the sensor unit 8 is formed around the rotating shaft 6 of the rotor R and surrounded by the vertical wall 7. The housing portion 9 has four screws. 10 is closed by the lid 2.

A boss portion 11 is provided at the center of the front surface of the stator base 4. A stepped portion 12 is formed around the boss portion 11, and a stator core 14 having twelve teeth 13 in the radial direction is disposed on the stepped portion 12. The stator core 14 is attached to the boss portion 11 from the axial direction of the rotary shaft 6 by three fixing bolts 15. The stator core 14 is formed by laminating metal plates made of a magnetic material in the axial direction of the rotary shaft 6, and a coil 17 is wound around each tooth 13 via an insulator 16 having a U-shaped cross section as an insulating material. It is disguised.
Here, on the inner wall 18 of each insulator 16, ring-shaped insulator rings 19 and 20 that rise in the axial direction of the rotary shaft 6 along the inner wall 18 are locked to the root portion of the insulator 16. A pair of front and rear sides of S are mounted. At the lower part of each insulator ring 19, 20, a cutout portion 37 is provided for reducing the height within an angle range of 90 degrees in order to enhance drainage (see FIG. 2). The stator S is composed of the stator base 4 and the stator core 14 around which the coil 17 is wound.

A recess 21 is formed around the boss 11 on the front surface of the stator base 4, and an annular terminal unit 22 is disposed in the recess 21. The terminal unit 22 is connected to the coils 17 corresponding to the U-phase, V-phase, and W-phase, and is fixed in a state where the U-phase, V-phase, and W-phase terminals 24 are pressed by a double nut 23. Here, the recess 21 is filled with the resin material J having excellent heat transferability around the terminal unit 22 and the terminal 24, and the heat generated in the coil 17 is effectively applied to the stator base 4 via the resin material J. Heated and quickly cooled.
As shown in FIG. 4, a cable 25 is connected to each terminal 24, and the terminal 24 and the cable 25 are covered with a waterproof tube 26.

A mounting hole 28 for the bearing holder 27 is formed at the center of the boss portion 11 of the stator base 4, and the bearing holder 27 is inserted therein.
As shown in FIGS. 5 and 6, the bearing holder 27 is an iron-made cylindrical member, and the first bearing 29 and the second bearing 30 are fitted and fixed to the front end portion and the rear end portion, respectively. The part 31 and the second holding part 32 are stepped. In this way, the bearing holder 27 is formed of the same iron (the same coefficient of thermal expansion) as the first bearing 29 and the second bearing 30, so that the bearing holder 27 and the first and second bearings 29, 30 are relative to each other. The degree of expansion and contraction due to heat is the same.
Therefore, compared with the case where the bearing holder 27 is made of aluminum, the change in the internal gap due to the expansion and contraction of the first bearing 29 and the second bearing 30 due to heat is greatly reduced, and the first bearing 29 and the second bearing 30 are reduced. Can improve the sound vibration performance and extend the service life. Further, by providing the bearing holder 27, only the bearing holder 27 can be changed without replacing the stator core 14, and the first and second bearings 29 and 30 can be used in different sizes, that is, the shaft diameter of the rotary shaft 6.

  Three flange portions 33 are formed around the neck portion of the first holding portion 31 of the bearing holder 27, and the flange portions 33 are fixed to the boss portion 11 of the stator base 4 by screws 34. Further, a water shield ring portion 35 extending outward is formed on the periphery of the front end portion of the first holding portion 31, and the water shield ring portion 35 is a cut portion in which a lower portion is cut in an angle range of 90 degrees in order to improve drainage. 38. An insertion hole 36 through which the rotary shaft 6 is loosely inserted is formed in the center portion of the bearing holder 27 on the first holding portion 31 side.

  A reduced diameter portion 40 is formed on the outer peripheral portion of the bearing holder 27 over the entire circumference, and an annular gap portion 41 is formed between the mounting hole 28 of the boss portion 11 and the reduced diameter portion. A communication hole 42 communicating with the inside of the bearing holder 27 is formed in the lower portion of 40. The reduced diameter portion 40 is formed in the storage portion 9 of the sensor unit 8 located on the rear end side of the mounting hole 28 of the boss portion 11 through the communication grooves 43 formed at three locations in the circumferential direction on the rear end portion of the bearing holder 27. Communicate.

As shown in FIG. 1, a communication hole 44 is formed in a lower portion of the boss portion 11 of the stator base 4 at a position communicating with the gap portion 41 toward the lower portion, and this communication hole 44 is an outer peripheral wall of the boss portion 11. The terminal unit 22 is opened to the arrangement site.
The mounting hole 28 of the boss portion 11 is formed as a storage portion 9 of the sensor unit 8 at a portion rearward of the rear end portion of the bearing holder 27. A disc-shaped sensor magnet 47 that is fixed to the rear end screw portion 45 of the rotating shaft 6 by a nut 46 and rotates together with the rotating shaft 6 is accommodated in the accommodating portion 9. As shown in FIG. 4, a fan-shaped sensor case 49 is fixed to the screw hole 48 of the stator base 4 with a screw 50 corresponding to the sensor magnet 47. The sensor magnet 47 and the sensor case 49 constitute a sensor unit 8.
The sensor case 49 is a member in which a circuit component 56 is housed. As shown in FIG. 7, the sensor case 49 has a vertical wall 58 on the both ends of the sensor case 49 and a screw hole 48 in the screw hole 48 of the stator base 4. A pair of attachment pieces 51 are formed which are tightened by (see FIGS. 3 and 4). A long mounting hole 52 for positioning is provided in the mounting piece 51 so that the sensor case 49 can be moved along the rotational peripheral surface of the sensor magnet 47.

  As shown in FIGS. 1 and 3, a rib portion 53 extending in the radial direction from the vertical wall 7 of the storage portion 9 is provided in the lower portion of the stator base 4, and a drainage passage 54 is formed in the rib portion 53. . The upper end of the drainage passage 54 communicates with the storage portion 9, the lower end of the drainage passage 54 is not opened linearly, is closed with screws, and the opening end 55 is bent forward and opened at the front surface of the stator base 4. A harness 57 is connected to the circuit component 56 in the sensor case 49.

8 and 9, R represents a rotor, and this rotor R is mainly disposed on the inner surface of the bottomed cylindrical rotor yoke 60 covering the stator S from the front surface and the peripheral wall 61 of the rotor yoke 60 corresponding to the coil 17 of the stator S. It is comprised with the magnet 62 made.
A boss 64 protruding forward is formed at the center of the bottom wall 63 of the rotor yoke 60, and the rotary shaft 6 is press-fitted into the boss 64. The distal end portion of the rotating shaft 6 protrudes from the end face of the boss 64, and this protruding portion is a screw portion 65, and a nut 66 is tightened here to fix the rotating shaft 6 to the boss 64 of the rotor yoke 60. The rotary shaft 6 is provided with a collar 67 that contacts the bottom wall 63 of the rotor yoke 60 from the back side, and the first bearing 29 is press-fitted and fixed from the front end side of the rotary shaft 6 so as to contact the collar 67. A plurality of drain holes 68 are formed in the bottom wall 63 of the rotor yoke 60 in the vicinity of the connection portion of the peripheral wall 61 along the circumferential direction.

  The peripheral wall 61 of the rotor yoke 60 is formed thicker than the bottom wall 63, and a magnet cover 69 is press-fitted and fixed to the inner surface of the peripheral wall 61. The opening edge 70 of the peripheral wall 61 of the rotor yoke 60 is disposed so as to face the front surface of the stator base 4 and extends to a position close to form a gap 71 between the front surface of the stator base 4 (see FIG. 1).

  As shown in FIGS. 10 and 11, the magnet cover 69 is formed by forming a plate material into a cylindrical shape, and the opening edge of the rear portion is enlarged to form a diameter-expanded portion 72, and the diameter-expanded portion 72 is formed on the rotor yoke 60. It is press-fitted and fixed to the inner surface of the peripheral wall 61. An inner flange portion 73 directed inward is formed at the opening edge of the front portion. A peripheral wall 74 extending from the enlarged diameter portion 72 to the inner flange portion 73 has a slightly smaller diameter than the inner surface of the peripheral wall 61 of the rotor yoke 60, and an accommodating portion 75 is formed between the peripheral wall 74 and the inner surface of the peripheral wall 61 of the rotor yoke 60. The magnets 62 are attached to the housing portion 75 at eight locations partitioned by the magnet holder 76 (see FIGS. 1 and 8).

  In the magnet cover 69, a plurality of drain holes 59 are formed in the circumferential direction at the ridge line portion between the inner flange portion 73 and the peripheral wall 74. Here, the drain hole 59 of the magnet cover 69 is located slightly inward in the radial direction with respect to the drain hole 68 of the rotor yoke 60, and the drain hole 68 of the rotor yoke 60 is positioned rearward in the axial direction of the rotating shaft 6. It can be effectively used as an inlet for the filler Z to be filled into the magnet 62.

As shown in FIGS. 1, 8, and 9, three attachment holes 77 are formed around the boss 64 of the bottom wall 63 of the rotor yoke 60, and the water shield ring 80 is formed in the attachment hole 77 from the back surface of the bottom wall 63. Rivet 81 is fixed.
As shown in FIG. 12, the water shield ring 80 is an annular member composed of an inner ring portion 82, an outer ring portion 83, and a bottom portion 84, and the outer ring portion 83 stands so that its diameter increases toward the rear rear side. The inner ring portion 82 is formed so as to rise along the axial direction of the rotating shaft 6. The peripheral portion of the outer ring portion 83 is inside the peripheral wall of the insulator ring 19 and close to the midway portion in the height direction, and the inner ring portion 82 is close to the outside of the water shield ring portion 35 of the bearing holder 27, and the water shield ring It stands up to a position that blocks the periphery of the portion 35.

  Therefore, as shown in FIG. 13, between the outer ring portion 83 of the water shield ring 80 and the peripheral wall of the insulator ring 19, a meandering and long path (see arrow) is provided in order to ensure the length of the water intrusion path. The labyrinth portion 98 is formed, and a labyrinth portion 99 that is a meandering and long path (see arrow) is also formed between the inner ring portion 82 of the water shield ring 80 and the water shield ring portion 35 of the bearing holder 27. The Rukoto.

  As shown in FIG. 1, a resin fan boss 86 is attached to the front surface of the bottom wall 63 of the rotor yoke 60 via six screws 85. The fan boss 86 includes a shoulder portion 87 that rises around the boss 64 of the bottom wall 63 of the rotor yoke 60, a bottom wall portion 88 that covers the bottom wall 63 of the rotor yoke 60, and a peripheral wall portion 89 that covers the peripheral wall 61 of the rotor yoke 60 to the middle portion. The fan blade 3 is fixed to the peripheral wall portion 89. Here, the outer peripheral portion of the bottom wall portion 88 of the fan boss 86 is formed in a stepped manner so as to be separated from the bottom wall 63 of the rotor yoke 60, so as not to close the drain hole 68 of the rotor yoke 60.

In the vicinity of the opening edge of the peripheral wall portion 89 of the fan boss 86, an annular waterproof ring 90 having a U-shaped cross section is fixed to the fan shroud 91 via the mounting piece 5, and the opening edge 70 of the peripheral wall 61 of the rotor yoke 60 and the stator are fixed. It arrange | positions in the position which covers the clearance gap 71 formed between the front surfaces of the base 4 from the outer side.
Therefore, a narrow gap 97 is formed between the opening edge of the fan boss 86 and the front flange portion 90 a of the waterproof ring 90.

  The front surface of the stator base 4 is close to the inner surface of the peripheral wall 61 of the rotor yoke 60, extends in front of the opening edge 70 of the rotor yoke 60 in the axial direction of the rotary shaft 6, and extends in the direction along the axial direction of the peripheral wall 61 and the rotary shaft 6. A ring portion 92 is formed so as to be overlapped. An end edge of the ring portion 92 extends to the front side of the rear end portion of the coil 17, and a protrusion 93 is provided at the terminal portion toward the inner surface of the peripheral wall 61 of the rotor yoke 60. Here, as shown in FIG. 2, the ridge 93 is cut off at an angle range of 90 degrees (see FIG. 2), and in this portion, the space between the peripheral wall 61 of the rotor yoke 60 and the ring portion 92 is a drainage portion. 100.

Therefore, as shown in FIG. 14, in order to ensure the length of the water intrusion path between the opening edge 70 of the rotor yoke 60 and the front surface of the stator base 4, the opening edge 70 of the peripheral wall 61 of the rotor yoke 60 and the stator base Thus, a labyrinth portion 94 that communicates with the gap 71 between the front surface 4 and the front surface 4 is formed.
Here, the labyrinth portion 94 wraps further outward from the space between the ring portion 92 and the inner surface of the peripheral wall 61 of the rotor yoke 60 by the protrusion 93, and meanders to form a long path (see arrow).

Therefore, according to the above embodiment, when the fan motor 1 is driven and the rotor R rotates, the cooling air is generated in the axial direction of the rotating shaft 6 by the fan blade 3 provided on the fan boss 86 and is used for heat exchange in the radiator. Cooling air can be supplied.
Here, since the rotor R of the fan motor 1 covers the stator S from the front surface, and this stator S is covered by the fan boss 86, it is possible to prevent water from entering from the front side.

Further, as shown in FIG. 15, even when water is splashed on the outer peripheral portion of the fan boss 86, a narrow gap 97 between the opening edge of the fan boss 86 and the front flange portion 90 a of the waterproof ring 90. Therefore, it is difficult for water to enter from here, which is advantageous for waterproofing.
Even if the air flows into the gap 97 (hereinafter, the flow of water is indicated by an arrow) and enters the gap 71 between the opening edge 70 of the peripheral wall 61 of the rotor yoke 60 and the front surface of the stator base 4, the gap 71 Is blocked by a ring portion 92 arranged so as to close the nozzle.

  In addition, the water in the gap 71 is discharged to the outside by centrifugal force due to the rotating operation of the rotor yoke 60, and even if it is not discharged, the labyrinth portion 94 that is continuous with the gap 71 as an entrance meanders, and the water is inside. Since it is difficult to enter, water intrusion is suppressed. Accordingly, since it is possible to prevent the intruded water from reaching the first bearing 29 and the second bearing 30, the outflow of the lubricant in the first bearing 29 and the second bearing 30 is suppressed, and the first bearing 29 and the second bearing 30 are prevented from flowing out. Lubricating performance can be maintained and sound vibration performance and durability can be improved. Further, since the labyrinth portion 94 is formed in the ring portion 92 of the stator S, water can be trapped by the ring portion 92. Here, the stator S is warmed by the heat generated by the electric motor 1, but water is trapped in the ring portion 92. Therefore, the cooling performance of the stator S can be improved by the specific heat of the trapped water and its vaporization heat. It becomes.

  By the way, in the labyrinth portion 94, the water whose momentum has been weakened is divided into one that flows downward from here and one that flows to the front side of the stator S, but most of the water flows to the first bearing from the front side by flowing downward. 29 and the second bearing 30 are reduced in water amount, which is advantageous for the first bearing 29 and the second bearing 30 in terms of waterproofing. Here, most of the water that has flowed downward is guided to the lower side along the ring portion 92 as it is, and the water drainage portion between the ring portion 92 from which the protrusion 93 is cut off and the peripheral wall 61 of the rotor yoke 60. The water is quickly drained from 100 through a gap 71 through a gap 97 between the opening edge of the fan boss 86 and the front flange portion 90a of the waterproof ring 90.

  The water flowing forward from the labyrinth portion 94 is prevented from entering further by the labyrinth portion 98 between the outer ring portion 83 of the water shield ring 80 and the peripheral wall of the insulator ring 19, and along the peripheral wall of the insulator ring 19. It is guided to the lower part, moves from the cut portion 37 of the insulator ring 19 through the drain hole 59 of the magnet cover 69 to the drain hole 68 provided on the outer peripheral side of the bottom wall 63 of the rotor yoke 60, and from here the fan boss 86 The inside of the peripheral wall portion 89 is guided downward, and is quickly drained through a gap 97 between the opening edge of the fan boss 86 and the front flange portion 90 a of the waterproof ring 90. Therefore, the labyrinth portion 94 and the labyrinth portion 98 can prevent water from entering twice, so that the first bearing 29 and the second bearing 30 can be reliably prevented from getting wet.

Further, even if water reaches between the outer ring portion 83 and the inner ring portion 82 of the water shield ring 80 from the labyrinth portion 98, most of the water that has lost its momentum is in contact with the inner ring portion 82 and the bearing of the water shield ring 80. Further intrusion is prevented by a labyrinth portion 99 formed between the holder 27 and the water shield ring portion 35, guided downward along the peripheral wall of the bearing holder 27, and from the cut portion 38 of the water shield ring portion 35. Guided to the outer ring portion 83 of the water shield ring 80 and reaches the drain hole 59 of the magnet cover 69. And it moves to the drain hole 68 in the same manner as described above, and is guided downward in the peripheral wall portion 89 of the fan boss 86 from here, and the gap between the opening edge of the fan boss 86 and the front flange portion 90a of the waterproof ring 90 It is quickly drained through 97. Therefore, in addition to the labyrinth portion 94 and the labyrinth portion 98, the labyrinth portion 99 is also added, so that water can be prevented from entering three times.
In particular, it is possible to effectively prevent the first bearing 29 and the second bearing 30 from being exposed to water by the labyrinth portion 94 at the water entrance and the labyrinth portion 99 immediately before the first bearing 29.

Even if the air inside the bearing holder 27 expands and contracts due to a temperature change, the air passes through the communication hole 42 and the gap 41 and escapes from the communication hole 44, the drainage part 100 and the gap 71, or communicates therewith. It can escape from the drainage passage 54, the open end 55, and the gap 71 through the hole 42, the gap 41, the communication groove 43, and the storage portion 9. Therefore, as in the case where the insides of the first bearing 29 and the second bearing 30 are hermetically sealed, the grease does not flow to the outside due to a change in internal pressure, thereby preventing deterioration of sound vibration performance and deterioration of durability due to lack of lubrication. be able to.
And since the internal space of the bearing holder 27 communicates with the outside in this way, even if the fan motor 1 is submerged or submerged, the internal water can be quickly removed from the path described above. It drains from the gap 71.

  By the way, since the cooling air inlet is not provided on the front surface of the rotor R, the cooling air cannot be taken into the fan motor 1, but the heat generated in the coil 17 passes through the resin material J having high heat conduction performance. Since heat is drawn by the stator base 4, overheating of the coil 17 can be suppressed and cooling can be performed effectively.

Next, a second embodiment of the present invention will be described with reference to FIG.
In this embodiment, an annular groove 95 is formed on the front surface of the stator base 4 at a portion facing the opening edge 70 of the peripheral wall 61 of the rotor yoke 60, and the groove 95 is crank-shaped outward from the opening edge 70 of the rotor yoke 60. The terminal part 70a which bends is provided to the terminal part 70a. The groove 95 is deeply carved on the lower side, and a labyrinth portion 94 ′ (see arrow) having a long distance is formed by meandering between the groove 95 and the end portion 70 a of the opening edge 70.

Also in this embodiment, since the infiltration of water by the labyrinth part 94 ′ can be reliably suppressed, the infiltration of water into the first bearing 29 and the second bearing 30 together with the labyrinth part 99 is reliably suppressed, and the first bearing 29, the grease of the second bearing 30 flows due to the infiltrated water, the lubrication performance is lowered, and it is possible to prevent deterioration of sound vibration and deterioration of durability.
In particular, in this embodiment, since the terminal portion 70a is bent outwardly in a crank shape, when the rotor yoke 6 rotates, the attached water moves to the tip of the terminal portion 70a located on the outer side due to centrifugal force. This is advantageous.
Since other configurations and operations are the same as those in the above-described embodiment, description thereof will be omitted.

  In addition, as shown in FIG. 17, a groove 95 ′ may be formed obliquely downward, and a terminal portion 70a ′ extending outward from the opening edge 70 of the rotor yoke 60 may extend linearly and face the groove 95 ′. Good. With this configuration, a labyrinth portion 94 ″ (see arrow) having a long distance is formed by meandering. In particular, in this embodiment, since the upper surface (outer surface) 96 of the groove 95 ′ is opened obliquely upward, the water in the groove 95 ′ is obliquely upward from the upper surface 96 of the groove 95 ′ by rotating the rotor yoke 60. This is advantageous in terms of drainage.

  The present invention is not limited to the above-described embodiment. For example, the case where the fan blade 3 is provided on the fan boss 86 has been described. However, the fan blade 3 is not directly provided on the peripheral wall 61 of the rotor yoke 60 without the fan boss 86 being provided. It may be provided. As the magnet 62, a neodymium magnet or a ferrite magnet can be used.

It is sectional drawing of the fan motor of embodiment of this invention. It is a front view of the stator of FIG. It is a rear view of FIG. 2 which abbreviate | omitted the sensor unit. It is a rear view of FIG. It is an expanded sectional view of the bearing holder of FIG. FIG. 6 is a front view of FIG. 5. It is a front view of a sensor case. It is sectional drawing of the rotor of FIG. It is a front view of FIG. It is a side view of the magnet cover of FIG. It is a front view of FIG. It is sectional drawing of the water shield ring of FIG. It is a principal part enlarged view of FIG. It is a principal part enlarged view of FIG. It is sectional drawing which shows the flow of water. It is sectional drawing equivalent to FIG. 13 of 2nd Embodiment. It is sectional drawing equivalent to FIG. 13 of other embodiment.

Explanation of symbols

4 Stator base 6 Rotating shaft 13 Teeth 17 Coil 27 Bearing holder (bearing holder)
29 First bearing (bearing)
30 Second bearing (bearing)
35 Water shield ring part 60 Rotor yoke 61 Peripheral wall (inner peripheral surface)
62 Neodymium magnet (permanent magnet)
63 bottom wall 70 opening edge 70a, 70a 'terminal part (opening edge)
82 Inner ring (ring-shaped member)
92 ring part 93 ridge 94 first labyrinth part (labyrinth part)
95, 95 ′ Groove 99 Second labyrinth part (labyrinth part)
S Stator R Rotor

Claims (5)

  A stator is formed by winding a coil around a plurality of teeth provided on the stator base, and a bottomed cylindrical rotor yoke that covers the stator from its front surface and a permanent magnet disposed on the inner peripheral surface of the rotor yoke. An electric motor comprising a rotor and having a rotation shaft provided at a central portion of the rotor and rotatably supporting the rotation shaft at a central portion of the stator base via a bearing, the opening edge of the rotor yoke and the stator At least two labyrinth portions are provided in a region from the base to the bearing, and at least one labyrinth portion is provided in a ring portion provided in the stator base and adjacent to the inner side of the peripheral wall of the rotor yoke, and further a protrusion An electric motor characterized by being formed by.   One of the two labyrinth parts is a first labyrinth part formed between the opening edge of the rotor yoke and the front surface of the stator base, and the other one is just before the bearing and is a bearing holder. The electric motor according to claim 1, wherein the electric motor is a second labyrinth portion formed between the rotor yoke and the rotor yoke.   3. The electric motor according to claim 2, wherein the first labyrinth portion is formed between a ring portion provided on the stator base and adjacent to an inner side of a peripheral wall of the rotor yoke and an opening edge of the rotor yoke. .   The first labyrinth portion is formed between an annular groove provided at a portion of the stator base facing the opening edge of the rotor yoke and an opening edge of the rotor yoke provided adjacent to the groove. The electric motor according to claim 2, wherein:   The second labyrinth portion includes a flange-shaped water shield ring portion extending outside the bearing holder, and a ring-shaped member extending along the rotation axis from the bottom wall of the rotor yoke in proximity to the outside of the water shield ring portion. The electric motor according to claim 2, wherein the electric motor is formed between the motor and the electric motor.

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