JP2012095402A - Electric motor for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric motor for a vehicle which can prevent fixation of a stator support member to a rotor due to freezing of remaining water on an inner peripheral side of a water intrusion regulating wall and thus, maintain stable startability even at cold time.SOLUTION: An approximately cylindrical water intrusion regulating wall 25 covering an outer side of an edge on an opening side of a bottomed cylindrical rotor is arranged in a bracket 12 supporting a stator. A recess 51 for partially expanding a separation width between a root part of the water intrusion regulating wall 25 and the edge on the opening side of the rotor is arranged in a region vertically below the inner peripheral face of the water intrusion regulating wall 25. Thus, even when water droplets remain on the root part side of the recess 51 due to surface tension and freeze, blocks of ice do not come into contact with the rotor.

Description

  The present invention relates to an electric motor for a vehicle used for a radiator cooling fan of an automobile.

As an electric motor used for a radiator cooling fan of an automobile, an outer rotor type brushless motor may be used.
This electric motor has a bottomed cylindrical shape in which a stator having a plurality of coils for excitation is attached to a bracket, which is a stator support member, and a plurality of magnets are attached to an inner peripheral surface on the outer peripheral side of the stator. The rotor is rotatably arranged, and the rotor is rotated by supplying current to each coil at different timings. A rotating shaft is integrally attached to the shaft center of the bottom wall portion of the rotor, and the rotating shaft is rotatably supported by a bracket via a bearing.

  Further, as this type of electric motor used in a vehicle, there is one in which a substantially cylindrical water intrusion restricting wall that covers the edge of the opening side of the peripheral wall portion of the rotor from the outer peripheral side is provided integrally with the bracket. The water intrusion restricting wall limits the inflow of water to the inner peripheral side of the rotor by covering the edge on the opening side of the peripheral wall portion of the rotor from the outer peripheral side. However, since the rotor is a component that rotates relative to the bracket, there is a gap between the water intrusion restriction wall and the peripheral wall of the rotor, so that water droplets are caused by rainwater blowing etc. May wrap around to the side. Thus, the water droplets that have traveled to the inner peripheral side of the water intrusion restriction wall travel along the inner peripheral surface of the water ingress restriction wall due to gravity and are discharged to the outside through the gap with the peripheral wall portion of the rotor in the lower region of the water ingress restriction wall .

In addition, an inner rotor type electric motor having a drainage structure in a motor case is also known (see, for example, Patent Document 1).
In this electric motor, a water drain hole that communicates the inside and outside of the case is provided at the lower end of the motor case that rotatably accommodates the rotor, and water droplets that have traveled along the inner wall are directed in the direction of the water drain hole on the inner surface of the lower region of the motor case. A guiding tapered surface is provided.

Japanese Utility Model Publication No. 62-21775

  In the case of the outer rotor type electric motor described above, the gap between the water intrusion restriction wall and the rotor needs to be reduced as much as possible. Therefore, the water droplets that have once entered the inner peripheral side of the water ingress restriction wall are not easily discharged to the outside. . For this reason, the technique of the inner rotor type electric motor described above is applied to the outer rotor type electric motor described above, a tapered surface is provided on the inner surface of the vertically lower region of the water intrusion regulation wall, and the inner side of the water ingress regulation wall is provided. We are considering discharging the water droplets that wrap around to the outside through the tapered surface.

However, even in the electric motor obtained in this manner, there is a possibility that water droplets may remain attached to the root portion of the tapered surface in the vertically lower region of the inner peripheral surface of the water intrusion restriction wall due to the action of surface tension. And the water droplet adhering to a root part in this way may freeze at the time of cold, and may stick over both in the clearance gap between a water permeation control wall and a rotor.
In particular, in an outer rotor type electric motor, the rotor is formed in a bottomed cylindrical shape and its axial length tends to be long. Therefore, in order to avoid an increase in the overall axial length of the motor, the gap between the rotor and the bracket should be as much as possible. Narrowing is desired. For this reason, in the outer rotor type electric motor, there is a high possibility that water droplets frozen at the root portion of the water intrusion restriction wall adhere to both the water ingress restriction wall and the rotor.

  Accordingly, the present invention provides a vehicular electric motor that can prevent the stator support member and the rotor from sticking due to freezing of residual water on the inner peripheral side of the water intrusion regulation wall, and can maintain stable starting performance even in cold weather. Is to provide.

The vehicle electric motor according to the present invention employs the following means in order to solve the above problems.
The invention according to claim 1 is a stator in which a coil is wound, a stator support member that supports the stator, and a rotation that is rotatably supported by the stator support member via a bearing and that extends in the horizontal direction. And a rotor that is formed in a bottomed cylindrical shape so as to cover the front side and the outer peripheral side of the stator, a magnet is installed on the peripheral wall portion, and the bottom wall portion is coupled to the rotary shaft so as to be integrally rotatable. The stator support member is provided with a substantially cylindrical water intrusion restricting wall that covers the outer periphery of the opening edge of the peripheral wall portion of the rotor. In the vertically lower region of the peripheral surface, a concave portion that partially enlarges the separation width between the root portion of the water intrusion restriction wall and the edge on the opening side of the rotor is provided.
As a result, water droplets flowing into the vertically lower region of the inner peripheral surface of the water intrusion regulation wall are discharged to the outside through the gap between the recess and the rotor. In addition, some water droplets may remain attached to the root side region of the water intrusion restriction wall in the recess due to surface tension, but the remaining water droplets are largely separated from the edge on the rotor opening side. Will do.

According to a second aspect of the present invention, in the electric motor for a vehicle according to the first aspect, the concave portion is constituted by a groove having a substantially V-shaped cross section that continues from a root portion to an extending end of the water intrusion restriction wall. It is characterized by being.
As a result, the water droplets flowing into the vertically lower region of the inner peripheral surface of the water intrusion regulation wall are smoothly discharged to the outside along the substantially V-shaped groove.

According to the first aspect of the present invention, in the vertically lower region of the inner peripheral surface of the water intrusion restriction wall, the concave portion that partially enlarges the separation width between the root portion of the water ingress restriction wall and the opening edge of the rotor. Therefore, even if some water droplets remain on the base side of the water intrusion regulation wall in the recess due to surface tension and freeze in cold weather, the frozen ice mass will enter the water. It is possible to reliably prevent the fixing between the regulation wall and the rotor.
Therefore, according to the present invention, stable starting performance can be maintained even during cold weather.

  According to the invention which concerns on Claim 2, the recessed part provided in the vertically downward area | region of the internal peripheral surface of a water permeation control wall is substantially V-shaped cross section which continues in the range which extends from the root part of a water permeation control wall to the extension end. Therefore, water droplets can flow smoothly along a groove having a substantially V-shaped cross section, and the remaining water droplets due to surface tension can be reduced.

It is a longitudinal section of a radiator cooling fan using an electric motor for vehicles of one embodiment of this invention. It is a perspective view of the stator support member of one Embodiment of this invention. It is the perspective view which expanded the principal part of the stator support member of one Embodiment of this invention. It is the perspective view which expanded the principal part of the stator support member of other embodiment of this invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view of a vehicular electric fan 1 (hereinafter referred to as “electric fan 1”) cut along a vertical direction. The arrow F in the figure indicates the front side of the vehicle. In the following description, the direction indicated by the arrow F is referred to as “front”, and the direction opposite to the direction indicated by the arrow F is referred to as “rear”.
The electric fan 1 is used for cooling a radiator of a vehicle and is installed on the front side of a radiator (not shown). The electric fan 1 includes an electric motor 2 (vehicle electric motor) that is a drive unit, and a fan body 3 that is rotationally driven by the electric motor 2.

  The electric motor 2 is constituted by an outer rotor type brushless motor, and is rotatably supported by a stator 11 around which a plurality of exciting coils 10 are wound, a bracket 12 (stator support member) that supports the stator 11, and the bracket 12. A rotating shaft 13 that is supported, a rotor 14 that is coupled to the rotating shaft 13 so as to rotate integrally therewith, and a control unit 15 that feeds back the rotation of the rotor 14 and controls energization of the coil 10 are provided.

The bracket 12 is formed in a substantially disk shape as a whole, and a plurality of fixed arms 12a as fastening portions are extended from the outer peripheral edge thereof. The fixed arm 12a is fastened and fixed to a fan shroud 16 that surrounds the periphery of the fan body 3 and guides air flow, and the fan shroud 16 is fixedly installed on the front side of the radiator.
Further, a cylindrical boss portion 12b protrudes from the center of the front surface side of the bracket 12, and a substantially cylindrical stator fixing pipe 17 (stator support pipe) that fixes the stator 11 on the outer peripheral side is provided on the boss portion 12b. Member) is attached.

  One end of the stator fixing pipe 17 is press-fitted and fixed in the boss portion 12b, and the other end protrudes forward from the front end portion of the boss portion 12b. The stator core 18 of the stator 11 is fitted and fixed to the outer peripheral surface of the region protruding forward from the boss portion 12 b of the stator fixing pipe 17. The stator core 18 is provided with a plurality of teeth 18a protruding in the radial direction, and the coils 10 are wound around the teeth 18a via insulators 19 which are insulating members.

A substantially cylindrical water intrusion restricting wall 25 is formed coaxially with the boss portion 12b on the outer peripheral edge of the bracket 12 on the front side. On the front surface of the bracket 12, a first cylindrical wall 26 having a smaller diameter than the water intrusion restriction wall 25 and a second cylindrical wall 27 having a smaller diameter than the first cylindrical wall 26 are formed coaxially with the boss portion 12b. Yes.
The water intrusion restriction wall 25 causes water droplets that are about to flow from the upper outer peripheral side of the bracket 12 to the central side where the electrical contacts and the control unit 15 are disposed, and drop downward along the outer peripheral surface, so that the direction of the center of the water droplets Functions to regulate intrusion into The first and second cylindrical walls 26 and 27 basically function in the same manner as the water intrusion restricting wall 25, and restrict the infiltration of water droplets in the center direction in a double or triple manner.

The rotating shaft 13 extends substantially horizontally along the longitudinal direction of the vehicle body, and is rotatably supported by the boss portion 12b of the bracket 12 and the stator fixing pipe 17 via a pair of bearings 20A and 20B. A rear end portion of the rotating shaft 13 protrudes rearward from the bearing 20A, and a sensor ring 21 for detecting rotation is attached to the protruding end. The rotation of the rotating shaft 13 detected using the sensor ring 21 is output to the control unit 15 as rotation information of the rotor 14. On the other hand, the front end portion of the rotating shaft 13 protrudes forward from the bearing 20B, and the rotor 14 and the fan body 3 are attached to the protruding portion.
Specifically, the rotor support portion 22 is formed in the projecting region on the front side of the rotating shaft 13 so as to be adjacent to the bearing 20 </ b> B, and the rotor support portion is adjacent to the rotor support portion 22. A fan fixing portion 23 having a diameter smaller than 22 is formed. Further, a male screw portion 24 having a smaller diameter than the fan fixing portion 23 is formed on the distal end side of the fan fixing portion 23 of the rotating shaft 13.

  In the rotor 14, a plurality of magnets 30 are attached to the inner surface of the peripheral wall portion 29 of the bottomed cylindrical rotor yoke 28 along the circumferential direction. Further, a boss portion 32 protruding to the same side as the peripheral wall portion 29 is formed at the center of the bottom wall portion 31 of the rotor yoke 28, and the boss portion 32 is press-fitted and fixed to the outer periphery of the rotor support portion 22 of the rotating shaft 13. Yes. The rotor 14 is assembled to the rotary shaft 13 so that the magnet 30 installed on the peripheral wall portion 29 faces the outer peripheral surface of the stator 11 and the bottom wall portion 31 covers the front side of the stator 11.

  Further, a flange 33 bent outward in the radial direction protrudes from the edge of the peripheral wall portion 29 of the rotor yoke 28 on the opening side (rear end side). The opening-side edge of the rotor yoke 28 including the flange 33 is formed between the water intrusion restriction wall 25 of the bracket 12 and the first cylinder when the rotor 14 is assembled to the bracket 12 via the rotary shaft 13 and the bearings 20A and 20B. It arrange | positions in the space between the walls 26, and overlaps the water intrusion control wall 25 and the first cylindrical wall 26 by a predetermined amount in the axial direction. The flange 33 functions as a restricting wall that restricts water droplets dripped onto the outer peripheral surface of the peripheral wall portion 29 of the rotor yoke 28 from flowing into the opening side of the peripheral wall portion 29, and also functions as a reinforcing portion of the rotor yoke 28.

On the other hand, the fan body 3 includes a bottomed cylindrical fan boss 34 and a plurality of blower blades 35 projecting radially outward from the outer peripheral surface of the fan boss 34. The fan boss 34 and the blower blade 35 are integrally formed of resin. An opening 36 is formed at the center of the bottom wall of the fan boss 34, and a separate metal plate 37 is attached from the rear side so as to close the opening 36. The metal plate 37 constitutes a shaft fixing portion for directly fixing the fan main body 3 to the rotating shaft 13, and a fitting hole into which the fan fixing portion 23 of the rotating shaft 13 is inserted in the center portion thereof. 38 is formed. In the fan body 3, the metal plate 37 is fitted to the fan fixing portion 23 of the rotating shaft 13 together with the washer 39, and the nut 40 is tightened on the male screw portion 24 of the rotating shaft 13 protruding from the metal plate 37. They are joined together. The washer 39 fitted to the fan fixing portion 23 together with the metal plate 37 abuts on the vicinity of the rotor support shaft portion 22 having a diameter larger than that of the fan fixing portion 23 on the rotating shaft 13. A space S that is spaced apart in the axial direction is secured between the bottom wall portion 31 and the metal plate 37. In the case of this embodiment, the metal plate 37 that is the shaft fixing portion is fixed to the bottom wall of the fan boss 34 by a plurality of screws 41.
Further, the edge on the opening side of the peripheral wall portion of the fan boss 34 is disposed so as to partially overlap the outer peripheral surface of the water intrusion restriction wall 25 of the bracket 12.

FIG. 2 is a perspective view of a single bracket 12 as viewed from the front side, and FIG. 3 is an enlarged view of a part of the bracket 12 of FIG.
As shown in these drawings, the water intrusion restricting wall 25 disposed on the outermost peripheral side of the bracket 12 has a circular curved surface in the entire inner peripheral surface excluding the vertically lower region. Hereinafter, the region of the inner peripheral surface forming the circular curved surface is referred to as a general portion 50 of the inner peripheral surface. In the vertically lower region of the inner peripheral surface of the water intrusion restricting wall 25, a concave portion 51 is formed in which the root portion side is recessed in a stepped shape by a predetermined depth d with respect to the general portion 50 of the inner peripheral surface. As shown in FIG. 1, the inner peripheral surface of the water intrusion restriction wall 25 has a gap at the opening edge (including the flange 33) of the peripheral wall portion 29 of the rotor 14 in a state where the rotor 14 is assembled to the bracket 12. However, since the concave portion 51 in the vertically lower region is recessed radially outward with respect to the general portion 50, the separation width from the edge portion on the opening side of the rotor 14 is another portion in this portion. It is partially enlarged with respect to (general part 50).

The concave portion 51 is formed in a groove shape in a range extending from the root portion of the water intrusion restriction wall 25 (the portion rising substantially horizontally from the vertical surface of the bracket 12) to the extending end. The bottom surface 51a of the recess 51 is an inclined surface that is inclined downward from the root portion toward the extending end.
Accordingly, the water droplets that have entered the inner peripheral side of the water intrusion restriction wall 25 are, as indicated by arrows w in FIG. 2, the inner peripheral surface of the water ingress restriction wall 25, the vertical surface of the bracket 12, and the first cylindrical wall 26. After flowing down the outer peripheral surface of the rotor 14 and flowing into the recessed portion 51 in the lower region, it is discharged to the outside through a gap between the opening-side edge of the rotor 14 and the recessed portion 51.

Here, the depth d of the recess 51 formed in the water intrusion restricting wall 25 is determined by the fact that water droplets adhere to the corner of the root of the water intrusion restricting wall 25 in the recess 51 due to surface tension, and the water droplets are frozen. In this case, the depth is set so that the ice block does not come into contact with the edge of the rotor 14 on the opening side when the ice block is formed.
2 and 3, reference numerals 53 and 54 denote waterdrop discharge tapered surfaces formed in the respective vertically lower regions of the inner peripheral surfaces of the first cylindrical wall 25 and the second cylindrical wall 26, respectively.

In the above configuration, when the coil 10 of the electric motor 2 is energized, a rotational force is generated between the stator 11 and the rotor 14, and the fan body 3 rotates together with the rotor 14 to cool the cooling air to the radiator. Will come to supply.
Further, when water is applied to the electric fan 1 by blowing rain water or the like, some of the water droplets may enter the gap between the fan boss 34 and the bracket 12 and further enter the inner peripheral side of the water entry restriction wall 25 of the bracket 12. However, the water droplets are further restricted from flowing inward by the first cylindrical wall 26 and the second cylindrical wall 27 as much as possible. The water droplets that have entered the inner peripheral side of the water intrusion restriction wall 25 flow down downward due to gravity, and are discharged to the outside of the electric fan 1 through the gap between the edge on the opening side of the rotor 14 and the recess 51 as described above.

In the electric motor 2 of this embodiment, the separation width between the root of the water intrusion restriction wall 25 and the opening edge of the rotor 14 is partially set in the vertically lower region of the inner peripheral surface of the water intrusion restriction wall 25. Since the expanding recess 51 is provided, even if a water droplet adheres to the corner near the root of the recess 51 due to surface tension and the water droplet may freeze as it is, the frozen ice mass enters the water. The problem of adhering the regulating wall 25 and the rotor 14 can be reliably avoided.
Therefore, in this electric motor 2, since the rotation of the rotor 14 is not hindered by the ice block stuck at the time of cold, stable starting performance can be maintained at all times.

FIG. 4 is a perspective view showing a part of a bracket 112 of an electric motor according to another embodiment of the present invention.
The electric motor of this embodiment is different only in the shape of the vertically lower region of the inner peripheral surface of the water intrusion restriction wall 25 of the bracket 112, and the configuration of other parts, the configuration of the applied electric motor, and the like are the same as those of the above embodiment. It has become the same. For this reason, the same code | symbol is attached | subjected to the same part as said embodiment, and the overlapping description shall be abbreviate | omitted.
In the bracket 112 of this embodiment, a taper groove 60 that is inclined downward from the root side of the water intrusion restriction wall 25 toward the extending end side is provided in a vertically lower region of the inner peripheral surface of the water ingress restriction wall 25. A groove 61 having a substantially V-shaped cross section is formed at the lowest position in the center in the circumferential direction (width direction) of the tapered groove 60 so as to extend from the root of the water intrusion restriction wall 25 to the extending end. In this embodiment, the groove 61 having a substantially V-shaped cross section constitutes a recess that partially enlarges the separation width between the root portion of the water intrusion restriction wall 25 and the end edge on the rotor opening side.

  In the case of the electric motor of this embodiment, a groove 61 having a substantially V-shaped cross section is formed so that one end reaches the root of the water intrusion restriction wall 25 in the vertically lower region of the inner peripheral surface of the water intrusion restriction wall 25 of the bracket 112. Therefore, even if water droplets adhere to the corner on the base portion side of the groove 61 due to surface tension and freeze, the frozen ice block fixes the water intrusion restriction wall 25 and the rotor 14. The trouble can be avoided. Further, since the groove 61 having a substantially V-shaped cross section has a function of guiding the surrounding water droplets to the lower side, even when the water droplets are likely to stay on the base side of the tapered groove 60 due to surface tension, the water droplets are cross-sectionalized. It can be discharged to the outside through the substantially V-shaped groove 61.

  In addition, this invention is not limited to said embodiment, A various design change is possible in the range which does not deviate from the summary.

2 ... Electric motor 10 ... Coil 11 ... Stator 12, 112 ... Bracket (stator support member)
DESCRIPTION OF SYMBOLS 13 ... Rotating shaft 14 ... Rotor 17 ... Stator fixed pipe (stator support member)
25 ... Water permeation restriction wall 29 ... Peripheral wall 30 ... Magnet 51 ... Recess 61 ... Groove (recess)

Claims (2)

A stator wound with a coil;
A stator support member for supporting the stator;
A rotary shaft that is rotatably supported by the stator support member via a bearing and that extends in the horizontal direction;
A rotor that is formed in a bottomed cylindrical shape so as to cover the front side and the outer peripheral side of the stator, a magnet is installed on the peripheral wall portion, and the bottom wall portion is coupled to the rotary shaft so as to be integrally rotatable. In the vehicle electric motor,
The stator support member is provided with a substantially cylindrical water intrusion restriction wall that covers the outer periphery of the opening edge of the peripheral wall portion of the rotor,
In the vertically lower region of the inner peripheral surface of the water intrusion restriction wall, there is provided a recess that partially enlarges the separation width between the root portion of the water ingress restriction wall and the edge on the opening side of the rotor. The electric motor for vehicles characterized.   2. The vehicle electric motor according to claim 1, wherein the concave portion is configured by a groove having a substantially V-shaped cross section that extends from a root portion of the water intrusion restriction wall to an extending end.

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