JP6711330B2 - Electric motor - Google Patents

Description

The present invention relates to a DC electric motor with a brush.

Conventionally, a DC electric motor with a brush is known. The brush holding structure described in Patent Document 1 or 2 is used for a so-called open type electric motor in which the brush is exposed from the yoke of the motor.

U.S. Patent Application Publication No. 2002/0047467A1 China utility model publication No. 201590703U specification

In the open type electric motor having the brush holding structure described in Patent Document 1 or 2, when the brush is cooled by the wind flowing inside the cylindrical yoke, only a part of the wind is used for cooling the brush. Therefore, a large amount of cooling air is required. Therefore, this type of electric motor has a problem that it cannot be used in an environment in which the amount of air flowing inside the yoke is small.

For example, when an open type electric motor is used as an electric motor that rotates a fan included in an air conditioner, whether or not the open type electric motor can be used depends on the vehicle type in which the air conditioner is installed. Specifically, in a vehicle model in which a fan boss that covers the electric motor side of the fan can be used as a fan, the yoke of the electric motor increases as the rotation speed of the fan increases. The amount of air flowing from the inside to the fan side via the brush increases. Therefore, an open type electric motor can be used as long as it is an air conditioner installed in such a vehicle type. However, depending on the vehicle type, water may enter along with the wind sucked from the outside air when the outside air is introduced. In such a vehicle model, if there is a hole in the fan boss of the blower, water may enter the inside of the yoke of the electric motor through the hole. Therefore, in such a vehicle model, it is not possible to make a hole in the fan boss of the blower, and the amount of air flowing inside the yoke of the electric motor is reduced, so the temperature of the brush becomes high. Therefore, it is difficult to use an open type electric motor for an air conditioner installed in such a vehicle type.

The open type electric motor is not limited to an electric motor that rotates a fan included in an air conditioner, and can be used for various purposes. Even in that case, the open type electric motor has a problem of increasing the cooling capacity of the brush in an environment in which the amount of air flowing inside the yoke is small.

The present invention has been made in view of the above points, and an object thereof is to provide an electric motor capable of increasing the cooling capacity of a brush.

In order to achieve the above object, the invention according to claim 1 is
A cylindrical yoke (10),
A stator (30) composed of a magnet fixed to the yoke,
A rotor (40) that is rotatably provided with respect to the stator, and around which a coil (42) is wound;
A shaft (50) fixed to the rotor,
A commutator (60) electrically connected to the coil and rotating with the shaft;
A brush (70) that is in sliding contact with the commutator and supplies current to the coil via the commutator;
Air is blown toward the funnel inner diameter toward the rotor side to the commutator side is formed to gradually reduce a tapered shape the outer edge of the radially outer contact or adjacent to the yoke (81), from the inside of the leakage DOO portion to the brush An outlet (82) , and a cooling air guide (80) having a guide portion (83) extending from the funnel portion toward the brush and guiding air from the inside of the funnel portion to the outlet .

According to this, the wind that flows inside the yoke from the rotor side toward the commutator side is collected by the funnel portion of the cooling air guide, and the collected wind is blown out from the air outlet toward the brush. Therefore, the cooling air guide can efficiently cool the brush even when the amount of air flowing inside the yoke is small. Therefore, this electric motor can enhance the cooling capacity of the brush. As a result, it is possible to use a so-called open type electric motor with a brush exposed even in an environment in which the amount of air flowing inside the yoke is small.

In addition, the reference numerals in parentheses attached to the above-described respective components show an example of a correspondence relationship with a specific configuration described in an embodiment described later.

It is a figure which shows the cross-sectional structure of the electric motor which concerns on 1st Embodiment. It is a top view of the electric motor in the II direction of FIG. It is a side view of the electric motor in the III direction of FIG. It is a perspective view of the cooling air guide which concerns on 1st Embodiment. It is a top view of the cooling wind guide which concerns on 1st Embodiment. It is a side view of the cooling air guide in the VI direction of FIG. It is sectional drawing when the electric motor which concerns on 1st Embodiment is used for the air blower of an air conditioner. It is a figure which shows the cross-sectional structure of the electric motor of a comparative example. It is a perspective view of the cooling air guide of a comparative example. It is sectional drawing when the electric motor of a comparative example is used for the air blower of an air conditioner. It is sectional drawing when the electric motor of a comparative example is used for the air blower of another air conditioner. It is a graph which compared the brush cooling capacity of the electric motor which concerns on 1st Embodiment, and the electric motor of a comparative example. It is a partial cross section figure of the electric motor which concerns on 2nd Embodiment. It is a side view of the cooling air guide which concerns on 3rd Embodiment. It is a side view of the cooling air guide which concerns on 4th Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each of the following embodiments, the same or equivalent portions will be denoted by the same reference numerals, and description thereof will be omitted.

(First embodiment)
The first embodiment will be described with reference to the drawings. The electric motor 1 of the first embodiment is used, for example, as an electric motor for rotating a fan included in a vehicle air conditioner. As shown in FIG. 1, the electric motor 1 is installed inside a motor housing 2 attached to an air conditioning case (not shown) included in the vehicle air conditioner. 2 and 3 show only the electric motor 1 and the motor housing 2 is omitted.

As shown in FIGS. 1 to 3, the electric motor 1 is a DC electric motor with a brush. The electric motor 1 includes a yoke 10, a front plate 20, a stator 30, a rotor 40, a shaft 50, a commutator 60, a brush 70, a cooling air guide 80, and the like.

The yoke 10 is formed of a magnetic material into a cylindrical shape. One side and the other side of the yoke 10 in the axial direction are open. A motor case 11 is provided radially outside the yoke 10. The motor case 11 is formed of resin or the like into a cylindrical shape. An elastic member 12 such as rubber is provided on the outer side of the motor case 11. The electric motor 1 is fixed to the inner wall of the motor housing 2 via the elastic member 12. As a result, the vibration of the electric motor 1 is absorbed by the elastic member 12. Therefore, in the electric motor 1, the vibration thereof is reduced from being transmitted to the air conditioning case via the motor housing portion 2.

A front plate 20 is provided at one opening in the axial direction of the yoke 10. The front plate 20 connects one portion in the radial direction of the yoke 10 and the other portion. The front plate 20 is provided so as to straddle one portion and the other portion of the yoke 10 in the radial direction. A bearing 21 is provided inside the cup portion 27 provided at the center of the front plate 20. The front plate 20 rotatably supports the shaft 50 via a bearing 21.

A rear plate 25 is provided on the other opening of the yoke 10 in the axial direction. Although not shown, the rear plate 25, similarly to the front plate 20, also connects one portion of the yoke 10 in the radial direction and the other portion of the yoke 10, and connects the one portion of the yoke 10 in the radial direction and the other portion of the yoke 10 in the radial direction. It is installed so as to straddle. A bearing 26 is also provided in the center of the rear plate 25. The rear plate 25 also rotatably supports the shaft 50 via bearings 26. The bearings 21 and 26 are not limited to rolling bearings, and sliding bearings or the like can be used.

The stator 30 is composed of a plurality of magnets fixed to the inner wall of the yoke 10. The stator 30 forms a field by arranging a plurality of magnets having N poles or S poles inward in the radial direction of the yoke 10 alternately in the circumferential direction of the yoke 10. The stator 30 of the present embodiment is composed of two permanent magnets arranged so that the S poles and the N poles face each other with the rotating shaft interposed therebetween.

The rotor 40 is provided radially inside the stator 30. The rotor 40 has a plurality of salient poles 41 formed of a magnetic material and a coil 42 wound around the salient poles 41. The shaft 50 is fixed to an axial hole 43 provided at the center of the rotor 40. The shaft 50 is rotatably supported by the front plate 20 and the rear plate 25 via bearings 21 and 26. The front plate 20 and the rear plate 25 are fixed to the yoke 10. Therefore, the rotor 40 is rotatably provided with respect to the stator 30 fixed to the yoke 10.

The commutator 60 is fixed to the outer wall of the shaft 50 between the bearing 21 and the coil 42 provided on the front plate 20, and rotates together with the shaft 50. Although not shown, the commutator 60 has a plurality of commutator pieces divided in the circumferential direction. The plurality of commutator pieces are made of a conductive material such as a copper alloy and are insulated from each other. The wire of the coil 42 is electrically connected to each commutator piece.

The brush 70 is an electrode member that is in sliding contact with the commutator 60 and supplies a current to the coil 42 via the commutator 60. The brush 70 includes a positive electrode brush 71 and a negative electrode brush 72. Each of the positive electrode brush 71 and the negative electrode brush 72 has a sliding contact portion 73, a brush holder 74, and a spring 75.

The sliding contact portion 73 is made of a conductive material such as carbon or a metal having lubricity, and is in sliding contact with the commutator 60. The power supply wiring 76 is electrically connected to the sliding contact portion 73 of the positive electrode brush 71. The ground wiring 77 is electrically connected to the sliding contact portion 73 of the negative electrode brush 72. The brush holder 74 holds the sliding contact portion 73. An end portion of the brush holder 74 on the opposite side of the sliding contact portion 73 is locked to the locking portion 22 of the front plate 20. The spring 75 is provided on the brush holder 74 and presses the sliding contact portion 73 against the commutator 60 by elastic force. Thereby, the power supply wiring 76, the sliding contact portion 73 of the positive electrode brush 71, the commutator piece at a predetermined location of the commutator 60, the predetermined coil 42, the commutator piece at another location of the commutator 60, and the negative electrode. The sliding contact portion 73 of the brush 72 and the ground wiring 77 are electrically connected. When electric power is supplied to the power supply wiring 76 of the electric motor 1 and a current flows in the above order, magnetic poles are generated in the salient poles 41 of the rotor 40, and the electromagnetic force generated between the magnetic poles and the stator 30 causes the rotor 40 and The shaft 50 rotates.

By the way, when electric power is supplied to the electric motor 1, the brush 70 is heated around the sliding contact portion between the brush 70 and the commutator 60. Therefore, it is necessary to cool the brush 70. The vehicle air conditioner in which the electric motor 1 of the present embodiment is installed has a configuration in which the air flowing through the ventilation passage of the air conditioning case is introduced into the inner space 3 of the motor housing portion 2 via a cooling air passage (not shown). I have it. The cooling air introduced into the inner space 3 of the motor housing portion 2 passes through the opening between the rear plate 25 side of the yoke 10 and the magnet forming the stator 30 and the rotor 40, and the opening of the yoke 10 near the front plate 20 side. Flow toward. The electric motor 1 of the present embodiment includes the cooling air guide 80 between the rotor 40 and the brush 70 in order to efficiently cool the brush 70 using the cooling air flowing inside the yoke 10.

As shown in FIGS. 1 and 4 to 6, the cooling air guide 80 includes a funnel portion 81, a blowout port 82, a guide portion 83, a comma cover 84, and the like. 5 and 6, the position of the brush 70 is indicated by the alternate long and short dash line. Further, in FIG. 6, the cooling air blown out from the air outlet 82 is indicated by an arrow AF1.

The funnel portion 81 is formed in a tapered shape whose inner diameter gradually decreases from the rotor 40 side toward the commutator 60 side. The inner diameter D1 of the funnel portion 81 is formed larger than the outer diameter D2 of the commutator 60 (see FIG. 5). Therefore, the commutator 60 can rotate without contacting the funnel portion 81. Further, the outer diameter D3 of the funnel portion 81 is formed to be the same as or slightly smaller than the inner diameter D4 of the yoke 10 (see FIGS. 1 and 5). Therefore, the outer edge of the funnel portion 81 on the radially outer side is in contact with or adjacent to the yoke 10. Therefore, almost all of the wind flowing from the rear plate 25 side to the front plate 20 side inside the yoke 10 is collected by the funnel portion 81.

The air outlet 82 is an opening provided in the funnel portion 81. The blowout port 82 is provided from the inner peripheral edge of the funnel portion 81 to the middle in the radial direction so as to correspond to the shape of the brush 70. A guide portion 83 is provided around the air outlet 82. The guide portion 83 is provided so as to surround the radially outer side of the air outlet 82 and one and the other of the air outlets 82 in the circumferential direction. The guide portion 83 is formed so as to project in the axial direction from the funnel portion 81 toward the brush 70. Further, when the cooling air guide 80 is viewed from the radial direction, the guide portion 83 is formed in a throttle shape whose inner width gradually decreases from the rotor 40 side toward the brush 70 side. Therefore, the wind collected by the funnel portion 81 is guided to the air outlet 82 by the guide portion 83, and is blown from the air outlet 82 toward the brush 70 at an increased wind speed.

The comma cover 84 extends in the axial direction from the inner peripheral edge of the funnel portion 81, and is provided so as to surround the commutator 60 radially outside. The inner diameter D1 of the funnel portion 81 and the inner diameter D1 of the comma cover 84 are the same. The comma cover 84 can protect the commutator 60 from moisture and prevent the abrasion powder of the brush 70 and the commutator 60 from scattering. The inner diameter D1 of the comma cover 84 is formed larger than the outer diameter D2 of the commutator 60. Therefore, the commutator 60 can rotate without contacting the comma cover 84. Further, the comma cover 84 has a cutout portion 85 at a position where the brush 70 and the commutator 60 are in sliding contact with each other. The brush 70 passes through the cutout portion 85 of the comma cover 84 and is brought into sliding contact with the commutator 60.

The funnel portion 81 is provided with a claw portion 86 at a position corresponding to the front plate 20. The cooling air guide 80 is fixed to the front plate 20 by fitting the claw portion 86 into a hole (not shown) provided in the front plate 20.

FIG. 7 shows a state in which the electric motor 1 of the first embodiment is used as a blower of a vehicle air conditioner. A fan 6 for blowing air to the ventilation passage 5 of the air conditioning case 4 is attached to the shaft 50 of the electric motor 1. The fan 6 is, for example, a sirocco fan. No holes are made in the fan boss 7 that covers the electric motor 1 side of the fan 6.

When electric power is supplied to the electric motor 1, the fan 6 rotates and the air flows in the ventilation path 5 of the air conditioning case 4. Part of the wind flowing through the ventilation passage 5 is introduced into the inner space 3 of the motor housing portion 2 via a cooling air passage (not shown).

As shown by arrows AF2 and AF3 in FIG. 7, the cooling air introduced into the inner space 3 of the motor housing portion 2 is directed toward the inside of the yoke 10 and the outside of the yoke 10 from the rear plate 25 side toward the front plate 20 side. Flowing. The cooling air flowing inside the yoke 10 is collected by the funnel portion 81 of the cooling air guide 80, and is blown out from the air outlet 82 toward the brush 70. Since the cooling air guide 80 of the present embodiment is configured such that the outer edge of the funnel portion 81 on the radially outer side is in contact with or adjacent to the inner wall of the yoke 10, it is possible to collect almost all of the wind flowing inside the yoke 10. is there. The air collected by the funnel portion 81 of the cooling air guide 80 is blown toward the brush 70 from the air outlet 82. Therefore, the cooling air guide 80 of the present embodiment can efficiently cool the brush 70 even when the amount of air flowing inside the yoke 10 is small.

Here, for comparison with the present embodiment, the electric motor 100 and the cooling air guide 800 of the comparative example will be described.

As shown in FIGS. 8 and 9, the electric motor 100 of the comparative example is also a so-called open type in which the brush 70 is exposed from the yoke 10 as in the first embodiment. In the cooling air guide 800 included in the electric motor 100 of the comparative example, the funnel portion 810 has an outer diameter D5 smaller than the inner diameter D4 of the yoke 10 and smaller than the outer diameter D6 of the rotor 40. That is, the outer peripheral edge of the cooling air guide 800 of the comparative example and the inner wall of the yoke 10 are largely separated from each other. Therefore, the cooling air guide 800 of the comparative example has a configuration in which it is difficult to collect the air flowing inside the yoke 10 from the rear plate 25 side toward the front plate 20 side. Therefore, in the wind flowing from the rear plate 25 side to the front plate 20 side inside the yoke 10, only a part of the wind hits the brush 70, and most of the wind flows to the fan 6 side without hitting the brush 70. ..

FIG. 10 shows a state in which the electric motor 100 of the comparative example is used as a blower of a vehicle air conditioner. The fan 6 of the blower shown in FIG. 10 has a hole 8 formed in a fan boss 7 that covers the electric motor 100 side. Therefore, as shown by an arrow AF4 in FIG. 10, the air flowing inside the yoke 10 is sucked by the fan 6. Therefore, a large amount of air flows inside the yoke 10.

On the other hand, FIG. 11 shows a state in which the electric motor 100 of the comparative example is used as a blower of another vehicle air conditioner. In the fan 6 of the blower shown in FIG. 11, the fan boss 7 has no holes. Therefore, as shown by arrows AF5 and AF6 in FIG. 11, the air flowing inside and outside the yoke 10 is not sucked by the fan 6. Therefore, the amount of air flowing inside the yoke 10 is relatively small. When the electric motor 100 of the comparative example is installed in such an environment, the air volume of the cooling air that hits the brush 70 also decreases, and the brush 70 cannot be cooled sufficiently. Therefore, when the electric motor 100 of the comparative example is used in such an environment, there is a problem that the temperature of the brush 70 becomes high and the abrasion speed of the brush 70 becomes fast. Therefore, the electric motor 100 of the comparative example has a problem that it cannot be used in an environment where the cooling air flowing inside the rotor 40 is small.

FIG. 12 shows a brush 70 when the electric motor 1 of the first embodiment and the electric motor 100 of the comparative example are both mounted on a vehicle air conditioner with a fan 6 having no holes formed in the fan boss 7. It is a comparison of the temperatures of. The electric motor 1 of the first embodiment can significantly reduce the temperature of the brush 70 (for example, near 40° C.) compared to the electric motor 100 of the comparative example.

In contrast to the electric motor 100 of the comparative example described above, the electric motor 1 of the first embodiment has the following effects.

(1) In the first embodiment, the cooling air guide 80 blows out the air toward the brush 70 from the funnel portion 81 whose outer edge in the radial direction contacts or is adjacent to the yoke 10 and the inside of the funnel portion 81. It has an outlet 82. According to this, the wind flowing inside the yoke 10 is collected by the funnel portion 81, and the collected wind is blown out from the blowout port 82 toward the brush 70. Therefore, the cooling air guide 80 can efficiently cool the brush 70 even when the amount of air flowing inside the yoke 10 is small. Therefore, the electric motor 1 can enhance the cooling capacity of the brush 70. As a result, it is possible to use the so-called open type electric motor 1 in which the brush 70 is exposed even in an environment in which the amount of air flowing inside the yoke 10 is small.

(2) In the first embodiment, the cooling air guide 80 further has the commi cover 84 that extends in the axial direction from the inner peripheral edge of the funnel portion 81 and surrounds the commutator 60 radially outward. According to this, the commutator cover 84 can protect the commutator 60 from moisture and prevent the abrasion powder of the brush 70 and the commutator 60 from scattering. Therefore, when the electric motor 1 is used in a blower of a vehicle air conditioner, it is possible to prevent the evaporator and the like located on the downstream side of the blower from flowing air from being corroded by the abrasion powder.

(3) In the first embodiment, the cooling air guide 80 has the guide portion 83 extending from the funnel portion 81 toward the brush 70. The guide portion 83 guides the wind from the inside of the funnel portion 81 to the air outlet 82. According to this, the cooling air guide 80 can reliably apply the air collected by the funnel portion 81 to the brush 70 through the guide portion 83.

(4) In the first embodiment, the air outlet 82 is provided from the inner peripheral edge of the funnel portion 81 to the middle in the radial direction so as to correspond to the shape of the brush 70. According to this, the wind is blown out from the air outlet 82 according to the shape of the brush 70. Therefore, the cooling air guide 80 can lower the temperature of the desired portion of the brush 70 that requires cooling.

(5) The electric motor 1 according to the first embodiment includes the front plate 20 that connects the one radial portion and the other radial portion of the yoke 10 and rotatably supports the shaft 50. According to this, even when the electric motor 1 is a so-called open type in which the brush 70 is exposed, the brush 70 can be efficiently cooled.

(Second embodiment)
The second embodiment will be described. In the second embodiment, the configuration of the cooling air guide 80 is changed from that of the first embodiment, and the other points are the same as those of the first embodiment, so only the portions different from the first embodiment will be described. ..

As shown in FIG. 13, the cooling air guide 80 of the second embodiment is formed so that the outer edge portion 87 of the funnel portion 81 on the radially outer side is curved toward the front plate 20 and extends along the inner wall of the yoke 10. .. As a result, the outer diameter D3 of the cooling air guide 80 and the inner diameter D4 of the yoke 10 can be set to have substantially the same size. With such setting, it is conceivable that the outer diameter of the cooling air guide 80 is slightly larger than the inner diameter of the yoke 10 due to manufacturing tolerance. Even in that case, when the cooling air guide 80 is fitted into the inside of the yoke 10, the radially outer outer edge portion 87 of the funnel portion 81 is deformed along the inner wall of the yoke 10. Therefore, the cooling air guide 80 can be easily fitted inside the yoke 10. Therefore, in the second embodiment, it is possible to eliminate the gap between the cooling air guide 80 and the inner wall of the yoke 10 or to make the gap extremely small. As a result, in the second embodiment, almost all of the wind inside the yoke 10 is collected by the funnel portion 81 of the cooling air guide 80, and the collected wind is blown from the air outlet 82 toward the brush 70, so that the brush 70 The cooling capacity of can be further improved.

(Third Embodiment)
A third embodiment will be described. Also in the third embodiment, the configuration of the cooling air guide 80 is changed from that of the first embodiment, and since the other points are the same as those of the first embodiment, only parts different from the first embodiment will be described. ..

As shown in FIG. 14, in the third embodiment, the width W1 of the outlet 82 of the cooling air guide 80 is formed to be narrower than the width W2 of the brush 70. Also in this configuration, as shown by the arrow AF7, the wind collected by the funnel portion 81 is guided to the air outlet 82 by the guide portion 83, and is blown from the air outlet 82 toward the brush 70. Therefore, the cooling air guide 80 of the third embodiment can also efficiently cool the brush 70 even when the amount of air flowing inside the yoke 10 is small, as in the first and second embodiments.

(Fourth Embodiment)
A fourth embodiment will be described. Also in the third embodiment, the configuration of the cooling air guide 80 is changed from that of the first embodiment, and since the other points are the same as those of the first embodiment, only parts different from the first embodiment will be described. ..

As shown in FIG. 15, in the fourth embodiment, the cooling air guide 80 has a wall portion 88 that extends from the outer edge of the air outlet 82 and surrounds the outside of the brush 70. As a result, as shown by the arrow AF8, the wind blown from the air outlet 82 of the cooling air guide 80 toward the brush 70 is prevented from diffusing by the wall portion 88, and flows around the brush 70. Therefore, the cooling air guide 80 of the fourth embodiment can also efficiently cool the brush 70 even when the amount of air flowing inside the yoke 10 is small.

(Other embodiments)
The present invention is not limited to the above-described embodiments, but can be appropriately modified within the scope of the claims. Further, the above embodiments are not unrelated to each other, and can be appropriately combined unless a combination is obviously impossible. Further, in each of the above-mentioned embodiments, it goes without saying that the elements constituting the embodiment are not necessarily essential unless explicitly stated as being essential and in principle considered to be essential. Yes. Further, in each of the above-described embodiments, when numerical values such as the number of components of the embodiment, numerical values, amounts, ranges, etc. are referred to, it is clearly limited to a particular number and in principle limited to a specific number. The number is not limited to the specific number, except in the case of being performed. Further, in each of the above-mentioned embodiments, when referring to the shapes of the components and the like, the positional relationship, etc., unless otherwise explicitly stated and in principle, the shape, the positional relationship, etc., the shape thereof, It is not limited to the positional relationship or the like.

(1) In each of the above embodiments, the electric motor 1 used for the electric motor that rotates the fan 6 of the air conditioner has been described, but the usage of the electric motor 1 is not limited to this. The electric motor 1 can be used for various purposes as long as the brush 70 is cooled by the air flowing inside the cylindrical yoke 10.

(2) In each of the above embodiments, the permanent magnet field type electric motor 1 in which the stator 30 is made of a permanent magnet has been described. Field type).

(Summary)
According to the first aspect shown in some or all of the above-described embodiments, the electric motor includes a yoke, a stator, a rotor, a shaft, a commutator, a brush, and a cooling air guide. The yoke is formed in a tubular shape. The stator is composed of a magnet fixed to the yoke. A coil is wound around the rotor, and the rotor is rotatably provided with respect to the stator. The shaft is fixed to the rotor. The commutator is electrically connected to the coil and rotates with the shaft. The brush is in sliding contact with the commutator and supplies current to the coil via the commutator. The cooling air guide is formed in a taper shape in which the inner diameter gradually decreases from the rotor side toward the commutator side, and the outer edge in the radial direction is in contact with or adjacent to the yoke, and the inside of the funnel section faces the brush. It has an outlet that blows out the wind.

According to the second aspect, the cooling air guide further includes a comma cover that extends in the axial direction from the inner peripheral edge of the funnel portion and surrounds the radially outer side of the commutator. According to this, the commutator cover can protect the commutator from moisture and prevent the abrasion powder of the brush and the commutator from scattering. Therefore, when this electric motor is used in a blower of an air conditioner for a vehicle, it is possible to prevent an evaporator or the like located on the downstream side of the blower from flowing air from being corroded by abrasion powder.

According to the third aspect, the cooling air guide has a guide portion that extends from the funnel portion toward the brush and guides the wind from the inside of the funnel portion to the air outlet. According to this, the cooling air guide can reliably apply the air collected by the funnel portion to the brush through the guide portion.

According to the fourth aspect, the air outlet is provided from the inner peripheral edge of the funnel portion to a point on the radially outer side corresponding to the shape of the brush. According to this, the wind is blown out from the air outlet according to the shape of the brush. Therefore, this cooling air guide can reduce the temperature of a desired portion of the brush that requires cooling.

According to a fifth aspect, an electric motor includes a front plate that connects one portion and the other portion of the yoke in the radial direction to each other and rotatably supports the shaft. According to this, even when the electric motor is of a so-called open type in which the brush is exposed, the brush can be efficiently cooled.

1 electric motor
10 York
30 stator
40 rotor
50 shaft
60 commutator
70 brush
80 Cooling air guide
81 Funnel
82 Outlet

Claims (4)

A tubular yoke (10),
A stator (30) composed of a magnet fixed to the yoke,
A rotor (40), which is rotatably provided with respect to the stator, and around which a coil (42) is wound;
A shaft (50) fixed to the rotor,
A commutator (60) electrically connected to the coil and rotating with the shaft;
A brush (70) that is in sliding contact with the commutator and supplies a current to the coil through the commutator;
The brush from the inside of the funnel inner diameter toward the rotor side to the commutator side is formed to gradually reduce a tapered shape radially outward of the outer edge contact with or adjacent to said yoke (81), before Symbol funnel A cooling air guide (80 ) having a blowout port (82) for blowing air toward the brush, and a guide part (83) extending from the funnel portion toward the brush and guiding the wind from the inside of the funnel portion to the blowout port. ), and an electric motor. The electric motor according to claim 1, wherein the cooling air guide further includes a comma cover (84) that extends in an axial direction from an inner peripheral edge of the funnel portion and surrounds a radially outer side of the commutator. The electric motor according to claim 1 or 2 , wherein the blowout port is provided from the inner peripheral edge of the funnel portion to a middle portion on the radial outer side so as to correspond to the shape of the brush. The electric motor according to any one of claims 1 to 3 , further comprising a front plate (20) that connects one part and the other part of the yoke in the radial direction and rotatably supports the shaft. ..

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