JP6623909B2 - Brushless motor - Google Patents

Description

  The present invention relates to a brushless motor.

  2. Description of the Related Art Conventionally, as a brushless motor, there is a brushless motor including an annular stator, a rotor having a rotor magnet disposed radially outside of the stator so as to face the stator, and a cover for housing the rotor.

JP 2012-70615 A

  When the rotor is housed in the cover as in the brushless motor, it is possible to suppress the magnetic sound of the rotor from leaking to the outside. However, even if the rotor is covered with the cover, the vibration of the rotor may propagate to the cover via the air in the cover, and the cover may vibrate to generate noise.

  The present invention has been made in view of the above problems, and has as its object to further reduce the noise of a brushless motor.

  In order to solve the above problem, the brushless motor according to claim 1, wherein the rotating rotor, a plate portion disposed to face the rotor in the axial direction of the rotor, and the plate portion, the rotor A cover to be housed, a peripheral wall formed on the cover and surrounding the rotor, and a fitting wall formed on the cover and provided outside the peripheral wall and fitted to the plate portion. And a connecting rib for connecting the peripheral wall and the fitting wall.

  According to this brushless motor, the cover that houses the rotor has a peripheral wall that surrounds the periphery of the rotor. Therefore, leakage of the magnetic sound (resonant sound) of the rotor to the outside can be suppressed by the surrounding wall.

  Moreover, the cover is provided with a fitting wall provided outside the peripheral wall and fitted with the plate portion, and the fitting wall and the above-mentioned peripheral wall are connected by connecting ribs. Therefore, since the rigidity of the surrounding wall can be increased by the connecting rib, the surrounding wall resonates due to the magnetic sound of the rotor, the air in the surrounding wall vibrates, and the fitting wall vibrates due to the propagation of vibration from the surrounding wall. It is possible to suppress the occurrence of pronunciation. This makes it possible to further reduce the noise of the brushless motor as compared to a case where the periphery of the rotor is simply surrounded by a peripheral wall without using the connecting rib.

  In addition, since the connection with the surrounding wall via the connection rib is a fitting wall whose rigidity is increased by being fitted to the plate portion, the rigidity of the surrounding wall can be more efficiently increased. it can.

  According to a second aspect of the present invention, in the brushless motor according to the first aspect, a space is formed between the peripheral wall and the fitting wall, and the connection rib is formed around the peripheral wall. A plurality of spaces may be provided at intervals in the direction, and the space may be divided into a plurality of spaces by a plurality of the connection ribs.

  According to this brushless motor, a plurality of connecting ribs are provided at intervals in the circumferential direction of the peripheral wall, and a space formed between the peripheral wall and the fitting wall is formed by a plurality of connecting ribs. It is divided into spaces. Therefore, as compared with the case where there is only one space, the volume per one of the plurality of spaces is reduced, so that the resonance frequency of each space can be increased. Thereby, the resonance frequency of each space and the resonance frequency of the rotor can be made different, so that resonance between each space and the rotor can be suppressed, and noise can be further reduced.

  According to a third aspect of the present invention, in the brushless motor according to the first or second aspect, the connection rib may extend in a radial direction of the peripheral wall.

  According to this brushless motor, since the connecting rib extends in the radial direction of the peripheral wall, the rigidity of the peripheral wall can be effectively increased. Thus, the effect of suppressing vibration of the peripheral wall and air in the peripheral wall can be enhanced.

  According to a fourth aspect of the present invention, in the brushless motor according to the third aspect, the cover is formed with a cooling air intake located radially outward of the peripheral wall and configured to receive cooling air from outside, The fitting wall has an open shape having an opening between the peripheral wall and the cooling air inlet when viewed in the axial direction of the cover, and the opening of the fitting wall is formed in the cover, A rectifying wall extending in a tangential direction of the peripheral wall is disposed, the peripheral wall and the fitting wall are connected by a first connecting rib as the connecting rib extending in a radial direction of the peripheral wall, and the peripheral wall is connected to the peripheral wall. The straightening wall may be connected to the straightening wall by a second connecting rib that is perpendicular to the straightening wall when viewed in the axial direction of the cover.

  According to this brushless motor, a rectifying wall extending in a tangential direction of the peripheral wall is disposed in the opening of the fitting wall having an open shape, and the rectifying wall and the peripheral wall are connected by the second connecting rib. Are linked. Therefore, the rigidity of the rectifying wall can be increased by the second connecting rib, so that sound generation due to vibration of the rectifying wall can also be suppressed.

  In addition, since the second connecting rib forms a right angle with the rectifying wall when viewed in the axial direction of the cover, the rigidity of the rectifying wall can be effectively increased. Thereby, the vibration suppressing effect on the rectifying wall can be enhanced.

  As set forth in claim 5, in the brushless motor according to claim 4, the fitting wall has a pair of opposing walls disposed on both sides of the peripheral wall, and a length of the pair of opposing walls. And a connecting wall connecting one end in the direction, and the pair of opposed walls may be connected to the peripheral wall.

  According to this brushless motor, the pair of opposed walls formed on the fitting wall are connected to the peripheral wall. Therefore, it is possible to suppress the peripheral wall from vibrating over the entire circumference, and it is possible to enhance the vibration suppressing effect on the peripheral wall.

  According to a sixth aspect of the present invention, in the brushless motor according to the fifth aspect, both ends in the length direction of the rectifying wall may be connected to the pair of opposing walls.

  According to this brushless motor, both ends in the length direction of the rectifying wall are connected to the pair of opposing walls. Therefore, the rigidity of the pair of opposing walls can be increased by the rectifying walls, so that the vibration of the entire fitting wall including the pair of opposing walls can be more effectively suppressed.

  According to a seventh aspect of the present invention, in the brushless motor according to the fifth or sixth aspect, the cover has an outer peripheral wall that surrounds the fitting wall, and a length of the pair of opposed walls. The other end in the direction may be connected to the outer peripheral wall.

  According to this brushless motor, the other ends in the length direction of the pair of opposing walls are connected to the outer peripheral wall surrounding the fitting wall. Therefore, for example, the rigidity of the pair of opposing walls can be increased as compared with the case where the other ends in the length direction of the pair of opposing walls are free ends. Vibration of the entire fitting wall including it can be more effectively suppressed.

  As set forth in claim 8, in the brushless motor according to any one of claims 4 to 7, the cover has an outer peripheral wall surrounding the fitting wall, and the outer peripheral wall has And the rectifying wall may be connected to the rectifying wall at a right angle in the axial direction of the cover by a third connecting rib extending toward the cooling air inlet.

  According to this brushless motor, the outer peripheral wall surrounding the fitting wall and the rectifying wall are connected by the third connecting rib. Therefore, the rigidity of the rectifying wall can be increased by the third connecting rib, and the stiffness of the peripheral wall connected to the rectifying wall via the second connecting rib can also be increased. Thereby, the vibration of the surrounding wall and the rectifying wall can be more effectively suppressed.

  Moreover, since the third connecting rib is perpendicular to the rectifying wall when viewed in the axial direction of the cover, the rigidity of the rectifying wall and, consequently, the rigidity of the peripheral wall connected to the rectifying wall via the second connecting rib are reduced. Can be effectively increased. Thereby, the vibration suppressing effect on the rectifying wall and the surrounding wall can be enhanced.

  In addition, the third connecting rib forms a right angle with the straightening wall when viewed in the axial direction of the cover, and extends toward the cooling air inlet, so that the third connecting rib follows the flow of the cooling air taken in from the cooling air inlet. Three connecting ribs can be arranged. Thereby, it can suppress that the flow of the cooling air taken in from the cooling air intake is obstructed by the third connecting rib.

It is a front view including a partial section of a brushless motor concerning one embodiment of the present invention. FIG. 2 is an exploded perspective view of the brushless motor shown in FIG. 1 as viewed from one axial side. FIG. 2 is an exploded perspective view of the brushless motor shown in FIG. 1 as viewed from the other side in the axial direction. It is the figure which looked at the cover shown in FIG. 1 from the plate part side in the axial direction. It is the figure which looked at the cover concerning a comparative example from the same direction as Drawing 4.

  Hereinafter, an embodiment of the present invention will be described.

  As shown in FIG. 1, a brushless motor 10 according to one embodiment of the present invention includes a motor shaft 12, a stator 20, a rotor 30, a bearing holder 40, a center piece 50, a circuit board 60, A case 70 and a cover 80 are provided (see FIGS. 2 and 3 as appropriate). 1 to 3, an arrow A1 indicates one axial side of the brushless motor 10, and an arrow A2 indicates the other axial side of the brushless motor 10.

  The stator 20 has a stator core 21, an insulator 22, and a plurality of windings 23. Stator core 21 has a plurality of teeth portions 24 extending radially. The insulator 22 is mounted on the surface of the stator core 21, and the winding 23 is wound around each of the teeth portions 24 via the insulator 22. The whole of the stator 20 including the stator core 21 has an annular shape around the axial direction of the motor shaft 12, and anti-vibration rubber 25 is attached to an appropriate location in the circumferential direction of the inner peripheral portion of the stator core 21. This stator 20 forms a rotating magnetic field in the circumferential direction.

  The rotor 30 has a rotor housing 31 and a rotor magnet 32. The rotor housing 31 is formed in a hollow cylindrical shape having a peripheral wall portion 33 and a top wall portion 34, and houses the stator 20. The motor shaft 12 is press-fitted inside a cylindrical portion 35 formed at the center of the top wall portion 34, whereby the rotor housing 31 is fixed to the motor shaft 12 so as to be integrally rotatable. The rotor magnet 32 is fixed to the inner peripheral surface of the peripheral wall portion 33, and is disposed radially outside the stator 20 so as to face the stator 20.

  The bearing holder 40 has a holder part 41 and a cylindrical part 42. The holder portion 41 is formed in an annular shape having a larger diameter than the cylindrical portion 42, and is located on one axial side of the cylindrical portion 42. A first bearing 45 as a ball bearing is press-fitted inside the holder portion 41. The motor shaft 12 is press-fitted inside the inner ring of the first bearing 45, and the motor shaft 12 is inserted inside the cylindrical portion 42.

  The center piece 50 has a plate portion 51 and a shaft portion 52. The plate portion 51 is formed in a substantially flat shape with the axial direction of the motor shaft 12 as the plate thickness direction. The plate portion 51 is disposed on the other axial side of the rotor 30 so as to face the rotor 30, and covers the opening of the rotor housing 31 formed in a hollow cylindrical shape. The shaft 52 protrudes from the center of the plate 51 toward the stator 20 and is inserted inside the stator 20. This shaft portion 52 is formed in a substantially cylindrical shape. The cylindrical portion 42 of the bearing holder 40 described above is press-fitted inside the shaft portion 52, whereby the bearing holder 40 is fixed to the center piece 50.

  Further, a pedestal 53 is formed on the shaft 52 on the other axial side of the stator 20. The holder portion 41 and the pedestal portion 53 sandwich the anti-vibration rubber 25 from both sides in the axial direction of the stator 20, whereby the stator 20 is held by the center piece 50 via the anti-vibration rubber 25. On the opposite side of the central portion of the plate portion 51 from the shaft portion 52, a recessed accommodating portion 54 that opens on the side opposite to the side from which the shaft portion 52 projects is formed.

  A second bearing 55, which is a ball bearing, is press-fitted inside the housing portion 54. The motor shaft 12 is press-fitted inside the inner ring of the second bearing 55. The motor shaft 12 is rotatably supported by the bearing holder 40 and the center piece 50 by the second bearing 55 and the first bearing 45 described above.

  The circuit board 60 drives the stator 20, and is disposed on the opposite side of the plate portion 51 from the rotor 30. A plurality of electronic components are mounted on the circuit board 60. The plurality of electronic components include, for example, a switching element that is electrically connected to the plurality of windings 23 and switches a direction of a current flowing through the plurality of windings 23, a control element that controls a switching operation of the switching element, and the like. Is included.

  When the direction of the current flowing through the plurality of windings 23 is switched, a rotating magnetic field is formed by the stator 20. In addition, an attraction and a repulsive force act on the rotor magnet 32 according to the rotating magnetic field, whereby the rotor 30 rotates together with the motor shaft 12.

  The circuit case 70 is arranged on the side opposite to the rotor 30 with respect to the plate portion 51 and is assembled to the plate portion 51. The circuit case 70 is formed in a substantially concave shape that opens to the plate portion 51 side, and accommodates the circuit board 60 with the plate portion 51.

  The cover 80 is arranged on the side opposite to the circuit case 70 with respect to the plate 51 and is assembled with the plate 51 and the circuit case 70. The cover 80 is formed in a substantially concave shape that opens toward the plate portion 51, and accommodates the rotor 30 with the plate portion 51.

  Duct forming portions 71 and 81 extending in the radial direction of the brushless motor 10 are formed on the cover 80 and the circuit case 70, respectively, and the pair of duct forming portions 71 and 81 form a cylindrical duct 82. . More specifically, the duct forming portion 81 formed on the cover 80 extends radially outward from the cover 80 from an end of the cover 80 formed in a substantially concave shape on the opening side. A cooling air inlet 83 for taking in cooling air from the outside is formed at a distal end portion of the duct forming portion 81 formed in the cover 80. The cooling air taken in from the cooling air inlet 83 is supplied to the inside of the circuit case 70 and the inside of the rotor housing 31 through the inside of the duct 82.

  The cover 80 is made of resin and has a plurality of walls, ribs, and the like, as described in detail below. FIG. 4 is a diagram of the cover 80 shown in FIG. 1 viewed from the plate portion 51 side in the axial direction. As shown in FIG. 4, the cover 80 includes a ceiling wall 91, a peripheral wall 92, a fitting wall 93, a rectifying wall 94, an outer peripheral wall 95, a first connecting rib 101, a second connecting rib 102, and a Three connecting ribs 103 are formed.

  When the axial direction of the brushless motor 10 is the same as the axial direction of the cover 80, the ceiling wall 91 extends in a direction intersecting the axial direction of the cover 80. The peripheral wall 92, the fitting wall 93, the rectifying wall 94, the outer peripheral wall 95, the plurality of first connecting ribs 101, the plurality of second connecting ribs 102, and the plurality of third connecting ribs 103 are all covered by the cover 80. Are formed in the height direction of the axis direction. The peripheral wall 92, the fitting wall 93, the rectifying wall 94, the outer peripheral wall 95, the plurality of first connecting ribs 101, the plurality of second connecting ribs 102, and the plurality of third connecting ribs 103 are all top wall portions. It stands from 34 toward the plate portion 51 shown in FIG.

  The peripheral wall 92 is formed in an annular shape, and surrounds the periphery of the rotor 30 (see FIG. 1). The fitting wall 93 is provided outside the peripheral wall 92. As shown in FIG. 2, a double wall 56 is formed on the outer peripheral portion of the plate portion 51 along the outer peripheral portion, and the fitting wall 93 shown in FIG. 4 is shown in FIG. Fitted between the double walls 56.

  As shown in FIG. 4, the fitting wall 93 has an open shape having an opening 93 </ b> A between the surrounding wall 92 and the cooling air intake 83 when viewed in the axial direction of the cover 80. That is, the fitting wall 93 has a pair of opposing walls 96 disposed on both sides of the surrounding wall 92 and a connecting wall 97 that connects one end of the pair of opposing walls 96 in the longitudinal direction. ing.

  The connection wall 97 is located on the side opposite to the side of the cooling air intake 83 located radially outward of the peripheral wall 92. The pair of opposing walls 96 are parallel to each other and extend in a tangential direction of the peripheral wall 92. The central portions in the length direction of the pair of opposed walls 96 are connected to the peripheral wall 92, and are integrated with the peripheral wall 92. The other ends of the pair of opposed walls 96 in the longitudinal direction are connected to an outer peripheral wall 95 described later. The fitting wall 93 is formed to be higher than the peripheral wall 92.

  The flow regulating wall 94 is disposed in an opening 93A of the fitting wall 93 that opens toward the cooling air intake 83. The flow regulating wall 94 is parallel to the connecting wall 97 and extends in a tangential direction of the peripheral wall 92. The flow regulating wall 94 is located between the peripheral wall 92 and the cooling air intake 83 as viewed in the axial direction of the cover 80. The rectifying wall 94 has a function of rectifying the cooling air taken in from the outside through the cooling air intake 83 toward the board housing space in the circuit case 70 shown in FIG. Both ends in the length direction of the flow regulating wall 94 are connected to a pair of opposing walls 96. As shown in FIG. 1, this rectifying wall 94 is also fitted between the double walls 56 formed on the outer peripheral portion of the plate portion 51, similarly to the fitting wall 93 described above.

  The outer peripheral wall 95 is formed on the outer peripheral portion of the cover 80 and has an annular shape. The outer peripheral wall 95 is formed concentrically with the peripheral wall 92, and surrounds the periphery of the fitting wall 93. The height of the rectifying wall 94 is equal to or higher than the height of the peripheral wall 92.

  Each of the plurality of first connection ribs 101 is an example of the “connection rib” in the present invention. The plurality of first connection ribs 101 are located closer to the connection wall 97 than the connection between the peripheral wall 92 and the fitting wall 93. The plurality of first connection ribs 101 extend in the radial direction of the peripheral wall 92, and connect the peripheral wall 92 and the fitting wall 93. The plurality of first connecting ribs 101 are provided at intervals in the circumferential direction of the peripheral wall 92, and the space 98 formed between the peripheral wall 92 and the fitting wall 93 is formed of the plurality of first connecting ribs 101. The space 101 is divided into a plurality of spaces 98A by 101. The height of the plurality of first connecting ribs 101 is equal to the height of the peripheral wall 92.

  The plurality of second connecting ribs 102 extend from the flow regulating wall 94 toward the peripheral wall 92. The plurality of second connecting ribs 102 form a right angle with the rectifying wall 94 when viewed in the axial direction of the cover 80, and connect the peripheral wall 92 and the rectifying wall 94. The plurality of third connecting ribs 103 extend from the flow regulating wall 94 toward the cooling air inlet 83. The plurality of third connecting ribs 103 form a right angle with the rectifying wall 94 when viewed in the axial direction of the cover 80, and connect the outer peripheral wall 95 and the rectifying wall 94. The heights of the second connecting rib 102 and the third connecting rib 103 are equal to the height of the flow regulating wall 94.

  Next, the operation and effect of the embodiment of the present invention will be described.

  First, a comparative example will be described in order to clarify the operation and effect according to one embodiment of the present invention. FIG. 5 is a view of the cover according to the comparative example viewed from the same direction as FIG. The cover 180 according to the comparative example shown in FIG. 5 is different from the cover 80 according to the embodiment of the present invention described above in that a plurality of first connecting ribs 101, a plurality of second connecting ribs 102, and a plurality of third connecting ribs 102 are provided. The connecting rib 103 is omitted.

  According to the cover 180 according to the comparative example, since the peripheral wall 92 surrounding the rotor 30 (see FIG. 3 and the like) is formed, it is determined that the magnetic sound (resonant sound) of the rotor 30 leaks to the outside. 92.

  However, in the cover 180 according to this comparative example, the peripheral wall 92 resonates due to the magnetic sound of the rotor 30, or the air vibration in the peripheral wall 92 propagates to the fitting wall 93, causing the fitting wall 93 to vibrate and generate sound. May occur. In addition, there is a possibility that air vibration in the peripheral wall 92 leaks to the outside through a gap between the fitting wall 93 and the plate portion 51 (see FIG. 2 and the like) to generate sound. Therefore, further noise reduction is desired.

  On the other hand, according to the cover 80 according to the embodiment of the present invention shown in FIG. 4, the peripheral wall 92 and the fitting wall 93 provided outside the peripheral wall 92 are connected by the first connecting rib 101. I have. Therefore, since the rigidity of the peripheral wall 92 can be increased by the first connecting rib 101, the peripheral wall 92 resonates or the air in the peripheral wall 92 vibrates due to the magnetic sound of the rotor 30 shown in FIG. In addition, it is possible to prevent the fitting wall 93 from vibrating due to the propagation of the vibration from the surrounding wall 92 to generate sound. Thereby, further noise reduction can be realized as compared with a case where the periphery of the rotor 30 is simply surrounded by the peripheral wall 92 without using the connection rib as in the above-described comparative example.

  In addition, a plurality of first connecting ribs 101 are provided at intervals in the circumferential direction of the peripheral wall 92, and a space 98 formed between the peripheral wall 92 and the fitting wall 93 is provided with a plurality of first connecting ribs. The rib 101 is divided into a plurality of spaces 98A. Therefore, the resonance frequency of each space 98A can be increased by reducing the volume per one of the plurality of spaces 98A as compared with the case where there is one space 98. Thereby, the resonance frequency of each space 98A and the resonance frequency of rotor 30 can be made different, so that resonance between each space 98A and rotor 30 can be suppressed, and noise can be further reduced. .

  Also, since the fitting wall 93 connected to the peripheral wall 92 via the first connecting rib 101 is fitted to the plate portion 51 to increase the rigidity, the rigidity of the peripheral wall 92 is reduced. It can be more efficiently increased.

  Further, since the first connection rib 101 extends in the radial direction of the peripheral wall 92, the rigidity of the peripheral wall 92 can be effectively increased. Thus, the effect of suppressing the vibration of the peripheral wall 92 and the air in the peripheral wall 92 can be enhanced.

  A rectifying wall 94 extending in a tangential direction of the peripheral wall 92 is disposed in the opening 93A of the fitting wall 93 having an open shape. The rectifying wall 94 and the peripheral wall 92 are connected to each other by a second connecting rib. They are connected by 102. Therefore, the rigidity of the rectifying wall 94 can be increased by the second connecting rib 102, so that sound generation due to the vibration of the rectifying wall 94 can also be suppressed.

  Moreover, since the second connecting ribs 102 form a right angle with the rectifying wall 94 when viewed in the axial direction of the cover 80, the rigidity of the rectifying wall 94 can be effectively increased. Thereby, the vibration suppressing effect on the rectifying wall 94 can be enhanced.

  Further, a pair of opposed walls 96 formed on the fitting wall 93 are connected to the peripheral wall 92. Therefore, the peripheral wall 92 can be suppressed from vibrating over the entire circumference, so that the vibration suppressing effect on the peripheral wall 92 can be enhanced.

  Further, both ends in the length direction of the rectifying wall 94 are connected to a pair of opposing walls 96. Therefore, the rigidity of the pair of opposing walls 96 can be increased by the rectifying walls 94, so that the vibration of the entire fitting wall 93 including the pair of opposing walls 96 can be more effectively suppressed.

  The other ends of the pair of opposed walls 96 in the length direction are connected to an outer peripheral wall 95 surrounding the fitting wall 93. Therefore, for example, the rigidity of the pair of opposing walls 96 can be increased as compared with the case where the other ends in the length direction of the pair of opposing walls 96 are free ends. Vibration of the entire fitting wall 93 including the wall 96 can be more effectively suppressed.

  Further, an outer peripheral wall 95 surrounding the periphery of the fitting wall 93 and the above-described rectifying wall 94 are connected by a third connecting rib 103. Therefore, the rigidity of the rectifying wall 94 can be increased by the third connecting rib 103, and the rigidity of the peripheral wall 92 connected to the rectifying wall 94 via the second connecting rib 102 can also be increased. Thereby, the vibration of the peripheral wall 92 and the rectifying wall 94 can be more effectively suppressed.

  In addition, since the third connecting rib 103 is perpendicular to the rectifying wall 94 when viewed in the axial direction of the cover 80, the third connecting rib 103 is connected to the rectifying wall 94 via the rigidity of the rectifying wall 94, and furthermore, the second connecting rib 102. The rigidity of the peripheral wall 92 can be effectively increased. Thereby, the vibration suppressing effect on the rectifying wall 94 and the peripheral wall 92 can be enhanced.

  Further, the third connecting rib 103 forms a right angle with the rectifying wall 94 when viewed in the axial direction of the cover 80 and extends toward the cooling air intake 83, so that the cooling air taken in from the cooling air intake 83 can be removed. The third connecting rib 103 can be arranged along the flow. Accordingly, it is possible to suppress the flow of the cooling air taken in from the cooling air inlet 83 from being hindered by the third connecting rib 103.

  Next, a modified example of the embodiment of the present invention will be described.

  In the above embodiment, the plurality of first connecting ribs 101 are preferably provided at intervals in the circumferential direction of the peripheral wall 92, but may be one.

  In the above embodiment, the first connecting rib 101 preferably extends in the radial direction of the peripheral wall 92, but does not have to extend in the radial direction of the peripheral wall 92.

  In the above-described embodiment, the second connecting rib 102 and the third connecting rib 103 preferably form a right angle with the rectifying wall 94 when viewed in the axial direction of the cover 80, but form a right angle with the rectifying wall 94 when viewed in the axial direction of the cover 80. It does not have to form a right angle.

  In the above embodiment, the fitting wall 93 has an open shape, but may have an annular shape surrounding the peripheral wall 92.

  Further, in the above embodiment, both ends in the length direction of the rectifying wall 94 are preferably connected to the pair of opposing walls 96, but may not be connected to the pair of opposing walls 96.

  In the above embodiment, the other ends of the pair of opposed walls 96 in the length direction are preferably connected to the outer peripheral wall 95, but need not be connected to the outer peripheral wall 95.

  In the above embodiment, preferably, the second connecting rib 102 and the third connecting rib 103 are used. However, for example, when the vibration of the peripheral wall 92, the rectifying wall 94, the fitting wall 93, and the like can be suppressed. The second connection rib 102 and the third connection rib 103 may be omitted.

  As described above, one embodiment of the present invention has been described. However, the present invention is not limited to the above, and it goes without saying that various modifications can be made without departing from the gist of the present invention. It is.

DESCRIPTION OF SYMBOLS 10 ... Brushless motor, 12 ... Motor shaft, 20 ... Stator, 21 ... Stator core, 22 ... Insulator, 23 ... Winding, 24 ... Teeth part, 25 ... Anti-vibration rubber, 30 ... Rotor, 31 ... Rotor housing, 32 ... Rotor Magnet, 33: peripheral wall portion, 34: top wall portion, 35: cylindrical portion, 40: bearing holder, 41: holder portion, 42: cylindrical portion, 45: first bearing, 50: center piece, 51: plate portion, 52: Shaft, 53: Pedestal, 54: Housing, 55: Second bearing, 56: Double wall, 60: Circuit board, 70: Circuit case, 71: Duct forming part, 80: Cover, 81 ... Duct forming part, 82 duct, 83 cooling air intake, 91 ceiling wall, 92 peripheral wall, 93 fitting wall, 93A opening, 94 rectifying wall, 95 peripheral wall, 96 opposing wall 97 ... connecting wall, 98 ... space, 98A ... plurality of spaces, 101 ... (one example of a connecting rib) first connecting rib, 102 ... second connecting rib, 103 ... third connecting ribs

Claims (8)

A rotating rotor,
A plate portion disposed opposite to the rotor in the axial direction of the rotor,
A cover that houses the rotor with the plate portion,
A peripheral wall formed on the cover and surrounding the rotor;
A fitting wall formed on the cover and provided outside the peripheral wall and fitted with the plate portion,
A connection rib for connecting the peripheral wall and the fitting wall,
A brushless motor. A space is formed between the peripheral wall and the fitting wall,
A plurality of the connection ribs are provided at intervals in a circumferential direction of the peripheral wall,
The space is divided into a plurality of spaces by a plurality of the connection ribs,
The brushless motor according to claim 1. The connecting rib extends in a radial direction of the peripheral wall,
The brushless motor according to claim 1 or 2. In the cover, a cooling air inlet is formed, which is located radially outward of the peripheral wall and takes in cooling air from outside,
The fitting wall has an open shape having an opening between the peripheral wall and the cooling air inlet when viewed in the axial direction of the cover,
In the opening of the fitting wall, a flow regulating wall formed in the cover and extending in a tangential direction of the peripheral wall is disposed.
The peripheral wall and the fitting wall are connected by a first connecting rib as the connecting rib extending in a radial direction of the peripheral wall,
The peripheral wall and the rectifying wall are connected by a second connecting rib that is perpendicular to the rectifying wall when viewed in the axial direction of the cover,
The brushless motor according to claim 3. The fitting wall has a pair of opposing walls disposed on both sides of the peripheral wall, and a connecting wall that connects one end of the pair of opposing walls in a length direction,
The pair of opposing walls are connected to the peripheral wall,
The brushless motor according to claim 4. Both ends in the length direction of the rectifying wall are connected to the pair of opposed walls,
A brushless motor according to claim 5. An outer peripheral wall surrounding the fitting wall is formed on the cover,
The other end in the length direction of the pair of opposed walls is connected to the outer peripheral wall,
A brushless motor according to claim 5. An outer peripheral wall surrounding the fitting wall is formed on the cover,
The outer peripheral wall and the rectifying wall are perpendicular to the rectifying wall when viewed in the axial direction of the cover, and are connected by a third connecting rib extending toward the cooling air inlet.
The brushless motor according to any one of claims 4 to 7.

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