Brushless motor

Abstract

To provide a brushless motor capable of improving layout property.SOLUTION: A rotating shaft SH1 and an output shaft SH2 forming a wiper motor 10 are arranged to be parallel to each other, and a motor housing 21 and a gear housing 71 are arranged in an axial direction of the rotating shaft SH1 (output shaft SH2). Thereby, an outer appearance of the wiper motor 10 can be line-symmetrical to a line segment connecting the rotating shaft SH1 and the output shaft SH2. Accordingly, it is possible to eliminate the directionality of attachment on the right and left sides around the line segment connecting the rotating shaft SH1 and the output shaft SH2. Therefore, it becomes possible to improve layout property of the wiper motor 10.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a brushless motor having a motor section and a gear section. [Background technology]

[0002] Conventionally, brushless motors with reduction mechanisms that are small yet capable of outputting large torque have been used as drive sources for wiper devices, power window devices, etc., that are mounted on vehicles such as automobiles. Such in-vehicle brushless motors are described, for example, in Patent Document 1.

[0003] The brushless motor described in Patent Document 1 is a motor with a reduction mechanism that includes a worm reducer, in which a worm portion is integrally provided on a rotating shaft, and an output shaft that is perpendicular to the rotating shaft is fixed to a worm wheel that meshes with the worm portion. In this way, the brushless motor described in Patent Document 1 uses a worm reducer, so the rotating shaft and output shaft are perpendicular to each other. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-093977 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the technology described in Patent Document 1, the rotation shaft and the output shaft are perpendicular to each other, so the brushless motor has a shape in which the motor section protrudes significantly to the side of the reduction gear section. This has resulted in a problem of poor layout flexibility in vehicles. Specifically, for example, when using the brushless motor as a wiper motor, wiper motors with symmetrical shapes are required for right-hand drive vehicles and left-hand drive vehicles.

[0006] An object of the present invention is to provide a brushless motor that allows for improved layout flexibility. [Means for solving the problem]

[0007] In one aspect of the present invention, there is provided a brushless motor having a motor section and a gear section, wherein the motor section comprises: a rotating shaft having a first gear provided at a tip end thereof; a rotor having a bottom wall and a side wall, the bottom wall being fixed to a base end of the rotating shaft; a plurality of magnets fixed to the side wall and arranged in a circumferential direction of the rotor; a stator provided between the rotating shaft and the magnets in a radial direction of the rotor and having a coil wound thereon; and a motor housing that rotatably supports the rotating shaft and accommodates the rotor and the stator; and the gear section comprises: a second gear that meshes with the first gear; an output shaft having an output section provided at a tip end thereof and a base end thereof fixed to the second gear and parallel to the rotating shaft; and a gear housing that rotatably supports the output shaft and accommodates the second gear. The motor housing has a motor opening that opens toward the gear housing, and at least a portion of the motor opening is covered with a stator bracket that holds the stator. A magnetic sensor that faces the magnet in the axial direction of the rotating shaft is provided on the stator bracket. There are. [Effects of the Invention]

[0008] According to the present invention, since the rotating shaft and the output shaft are parallel to each other, it is possible to align the motor housing and the gear housing in the axial direction of the rotating shaft (output shaft). This allows the appearance of the brushless motor to be symmetrical about the line connecting the rotating shaft and the output shaft. Therefore, there is no need for installation directionality on the left or right side of the line connecting the rotating shaft and the output shaft. This allows for improved layout flexibility. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is a perspective view of the wiper motor as seen from the gear portion side. [Figure 2] FIG. 2 is a perspective view of the wiper motor as seen from the motor unit side. [Figure 3] FIG. 2 is a view taken along the arrow A in FIG. 1 (bracket omitted). [Figure 4]FIG. 4 is a cross-sectional view taken along line BB in FIG. [Figure 5] FIG. 5 is a cross-sectional view showing only the reduction mechanism of FIG. [Figure 6] FIG. 2 is an exploded perspective view showing the inside of the motor unit. [Figure 7] FIG. 2 is an exploded perspective view showing the inside of the gear portion. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0011] Figure 1 is a perspective view of the wiper motor seen from the gear side, Figure 2 is a perspective view of the wiper motor seen from the motor side, Figure 3 is a view seen from the arrow A in Figure 1 (bracket omitted), Figure 4 is a cross-sectional view along line BB in Figure 3, Figure 5 is a cross-sectional view showing only the reduction mechanism in Figure 4, Figure 6 is an exploded perspective view showing the inside of the motor part, and Figure 7 is an exploded perspective view showing the inside of the gear part.

[0012] [Wiper motor overview] 1 to 4 is a drive source for a wiper device (not shown) mounted on the front of a vehicle such as an automobile. The wiper motor 10 corresponds to the brushless motor of the present invention and is mounted near the windshield (not shown) of the vehicle. The wiper motor 10 is activated by operating a wiper switch (not shown) provided inside the vehicle, which causes a wiper member (not shown) provided on the windshield so as to be able to swing freely to perform a reciprocating wiping operation.

[0013] Specifically, the wiper motor 10 reciprocates wiper members provided on the driver's seat side and passenger seat side within a wiping range (not shown) between a lower inverted position and an upper inverted position on the windshield, thereby allowing the wiper members to wipe away rainwater and other debris adhering to the windshield, ensuring visibility ahead of the vehicle.

[0014] The wiper motor 10 includes a motor section 20 and a gear section 70. The motor section 20 and the gear section 70 are firmly fixed to each other by a total of five first fixing screws S1 (see FIG. 2).

[0015] 3, when the wiper motor 10 is viewed in the axial direction of the rotary shaft SH1 and the output shaft SH2, the wiper motor 10 is symmetrical on the left and right sides of the figure with respect to a line segment CT connecting the rotary shaft SH1 and the output shaft SH2. This eliminates the need for installation directionality on the left and right sides of the line segment CT, making it possible to easily install the wiper motor 10 on either the driver's seat side of a right-hand drive vehicle or the driver's seat side of a left-hand drive vehicle.

[0016] [Motor section] 2 and 4 to 6, the motor section 20 includes a motor housing 21 formed in a stepped, approximately dish-like shape by injection molding molten aluminum or other material. The motor housing 21 includes a motor accommodating section 22 and a base mounting section 23, with the motor accommodating section 22 being deeper than the base mounting section 23. Specifically, the depth of the motor accommodating section 22 is approximately five times the depth of the base mounting section 23.

[0017] The motor accommodating portion 22 has a first bottom wall 22a formed in a substantially disk shape and a first side wall 22b extending from the outer edge of the first bottom wall 22a in the axial direction of the rotating shaft SH1. A small-diameter stepped portion 22c is integrally formed in the center of the first bottom wall 22a and protrudes outward from the motor accommodating portion 22 (the lower side in FIG. 4). A first bearing B1 is mounted radially inward of the small-diameter stepped portion 22c to rotatably support the base end side (the lower side in FIG. 4) of the rotating shaft SH1. The first bearing B1 is prevented from coming off by a retaining member 24 mounted on the small-diameter stepped portion 22c.

[0018] Furthermore, a total of three first flanges 22d protruding radially outward from the first side wall 22b are integrally provided on the axial side of the first side wall 22b opposite to the side where the first bottom wall 22a is provided (the upper side in FIG. 4). First fixing screws S1 (three of the total five) for fixing the motor housing 21 to the gear housing 71 are inserted into each of these first flanges 22d.

[0019] The base mounting portion 23 also includes a second bottom wall 23a formed in a generally crescent shape and a second side wall 23b extending from the outer edge of the second bottom wall 23a in the axial direction of the rotation axis SH1. A base member 60 that holds the second sensor board SB2 is attached to the inside of the base mounting portion 23. Specifically, the second bottom wall 23a and the second side wall 23b of the base mounting portion 23 each hold the base member 60 securely.

[0020] Furthermore, a total of two second flanges 23c protruding radially outward from the second side wall 23b are integrally provided on the axial side of the second side wall 23b opposite to the side where the second bottom wall 23a is provided (the upper side in FIG. 4). First fixing screws S1 (two of a total of five) for fixing the motor housing 21 to the gear housing 71 are inserted into each of these second flanges 23c.

[0021] Here, the motor housing 21 is provided with a first opening 25 that opens toward the gear housing 71. This first opening 25 corresponds to the motor opening of the present invention and faces a second opening 76 of the gear housing 71. With the first opening 25 and the second opening 76 butted together, the motor housing 21 is firmly fixed to the gear housing 71 with a total of five first fixing screws S1. With the first opening 25 and the second opening 76 butted together, the motor housing 21 and the gear housing 71 are aligned in the axial direction of the rotation shaft SH1 (output shaft SH2).

[0022] 6, when viewed in the axial direction of the rotating shaft SH1, the motor accommodating portion 22 and the base mounting portion 23 are partially overlapped with each other, so that the motor housing 21 has a generally pot-shaped shape when viewed in the axial direction of the rotating shaft SH1.

[0023] 4 and 6, a brushless motor 30 that forms the motor section 20 is housed inside the motor housing section 22. The brushless motor 30 includes a rotor unit 40 and a stator unit 50.

[0024] [Rotor unit] The rotor unit 40 has a rotating shaft SH1 made of a round steel bar and a rotor body 41 formed in a generally dish shape. The base end of the rotating shaft SH1 is rotatably supported by a first bearing B1, and a pinion gear 42 is integrally provided on the tip end of the rotating shaft SH1. Here, the pinion gear 42 corresponds to the first gear in the present invention and is formed in a spiral shape by, for example, knurling or the like.

[0025] The rotor body 41 corresponds to the rotor in the present invention and rotates the rotary shaft SH1. The rotor body 41 is formed by pressing a steel plate (magnetic material) or the like to have a substantially U-shaped cross section. The rotor body 41 includes a rotor bottom wall 41a formed in a substantially disk shape and a cylindrical rotor side wall 41b extending from the outer edge of the rotor bottom wall 41a in the axial direction of the rotary shaft SH1. Here, the rotor bottom wall 41a corresponds to the bottom wall in the present invention, and the rotor side wall 41b corresponds to the side wall in the present invention.

[0026] Furthermore, a cylindrical small-diameter boss 41c extending in the axial direction of the rotating shaft SH1 is integrally formed at the center (rotation center) of the rotor bottom wall 41a. The base end of the rotating shaft SH1 is firmly fixed to the small-diameter boss 41c by press-fitting. This fixes the base end of the rotating shaft SH1 to the rotor bottom wall 41a, allowing the rotating shaft SH1 to rotate together with the rotor body 41.

[0027] Additionally, a plurality of magnets MG formed in a generally tile-like (generally arc-shaped) configuration are fixed to the radially inner side of the rotor side wall 41b. These magnets MG are arranged at equal intervals around the circumference of the rotor body 41 and are firmly fixed to the rotor side wall 41b with an epoxy resin adhesive. Therefore, the magnets MG will not peel off from the rotor body 41 as the rotor unit 40 rotates.

[0028] Here, the rotor body 41 has a rotor opening 41d that opens toward the gear housing 71 on the axial side opposite to the side where the rotor bottom wall 41a is provided. The stator core 51 of the stator unit 50 is inserted from the rotor opening 41d to the radially inner side of the rotor side wall 41b (magnet MG).

[0029] [Stator unit] The stator unit 50 includes a stator core 51 formed in a generally cylindrical shape. The stator core 51 is formed by laminating a plurality of thin steel plates (magnetic material) and includes a generally cylindrical core body 51a and a plurality of teeth 51b protruding radially outward from the core body 51a. Coils CL corresponding to U-phase, V-phase, and W-phase (three phases) are wound around each tooth 51b with a predetermined number of turns by concentrated winding, via insulators 52 made of an insulating material such as plastic. The stator core 51 corresponds to the stator in the present invention.

[0030] A driving current is supplied alternately to each of the three-phase coils CL at a predetermined timing from an on-board controller (not shown), causing the rotor unit 40, which is disposed radially outside the stator core 51, to rotate in a predetermined rotational direction with a predetermined driving torque.

[0031] As described above, the wiper motor 10 in this embodiment is an outer rotor type brushless motor. Therefore, compared to an inner rotor type wiper motor of the same size, the outer rotor type wiper motor 10 in this embodiment can have a larger magnet MG. Therefore, the outer rotor type wiper motor 10 can achieve both compact size and high output.

[0032] On the other hand, from another perspective, if it is sufficient to obtain the same output as a conventional wiper motor, a relatively large and inexpensive ferrite magnet or the like can be selected as the magnet. Therefore, the outer rotor type wiper motor 10 is advantageous in that it allows for cost reduction.

[0033] Furthermore, by making the wiper motor 10 an outer rotor type, the stator core 51 can be shaped so that the multiple teeth 51b protrude radially outward in the radial direction. Therefore, when winding the coil CL around each tooth 51b, it is possible to use a general-purpose (common) flyer winding machine, for example, a flyer winding machine used for brushed motors (basic structure), which is advantageous in terms of manufacturing (ease of assembly).

[0034] [Stator holder] 4 and 6, the stator core 51 is held by a stator holder 53. The stator holder 53 corresponds to the stator bracket of the present invention. The stator holder 53 is formed into a substantially semicircular dish shape by injection molding molten aluminum material or the like, and has the function of accurately positioning the stator core 51 at a specified position relative to the rotor body 41.

[0035] The stator holder 53 covers a portion of the first opening 25 that forms the motor housing 21. The stator holder 53 has a first surface SF1 on the motor housing 21 side and a second surface SF2 on the gear housing 71 side.

[0036] A bearing holder 54 is integrally provided approximately in the center of the stator holder 53 on the first surface SF1 side. The bearing holder 54 holds a second bearing B2, which rotatably supports the axial center of the rotating shaft SH1. The second bearing B2 is sandwiched between the bearing holder 54 and a bearing fixing member 55. The bearing fixing member 55 is firmly fixed to the bearing holder 54 by a total of three second fixing screws S2 (see FIGS. 4 and 6). The bearing fixing member 55 is also made of aluminum.

[0037] The stator core 51 is fixed to the first surface SF1 side of the stator holder 53. Specifically, the core body 51a of the stator core 51 is fixed to the first surface SF1 side of the stator holder 53 by a total of three third fixing screws S3 (see FIGS. 4 and 6). The rotating shaft SH1 is rotatably disposed radially inside the core body 51a in a non-contact state. In this way, the stator core 51 is disposed between the rotating shaft SH1 and the magnet MG in the radial direction of the rotor body 41.

[0038] Furthermore, a first sensor board fixing portion 56 is provided integrally with the stator holder 53 on the first surface SF1 side and at a portion radially outward of the bearing holder 54. The first sensor board fixing portion 56 is provided on the first surface SF1 so as to be recessed in the axial direction of the rotation shaft SH1, and the first sensor board SB1 is provided on the first sensor board fixing portion 56. Specifically, the first sensor board SB1 is fixed to the first sensor board fixing portion 56 by a pair of fourth fixing screws S4 (see FIG. 6).

[0039] Here, a total of three Hall sensors HS (only one is shown in FIG. 4) are mounted on the first sensor board SB1. These Hall sensors HS correspond to the magnetic sensors of the present invention and correspond to the U phase, V phase, and W phase, respectively. In this way, the three Hall sensors HS are provided on the stator holder 53, and these Hall sensors HS each face a magnet MG fixed to the rotor side wall 41b in the axial direction of the rotating shaft SH1.

[0040] As a result, the on-board controller determines the rotational state (rotational speed, rotation direction, etc.) of the rotating shaft SH1 based on the detection signals (rectangular wave signals) from each Hall sensor HS, and accurately controls the rotational state of the rotating shaft SH1. As described above, in the wiper motor 10 of this embodiment, the magnet MG fixed to the rotor body 41 is used to detect the rotational state of the rotating shaft SH1. Therefore, a dedicated sensor magnet for detecting the rotational state of the rotating shaft, as in the past, is not required. As a result, the wiper motor 10 can be made smaller and lighter while reducing the number of parts.

[0041] 6, a pair of arc-shaped support protrusions 57 are integrally formed on the second surface SF2 side of the stator holder 53 to slidably support the second side surface 78f (see FIG. 7) of the helical gear 78 that forms the gear portion 70. This reduces the inclination of the helical gear 78, allowing the wiper motor 10 to operate smoothly. This improves the quietness of the wiper motor 10.

[0042] Furthermore, an arc-shaped engagement protrusion 58 is integrally provided on the second surface SF2 side of the stator holder 53 so as to surround the rotation shaft SH1. This arc-shaped engagement protrusion 58 is adapted to fit into a stator holder positioning recess 73d (see FIG. 7) of the gear housing 71. This allows the stator holder 53 to be positioned accurately in the correct position relative to the gear housing 71.

[0043] 6, a total of three screw insertion holes 53a are provided in the outer edge portion of the stator holder 53. First fixing screws S1 (three of the total five) for fixing the motor housing 21 to the gear housing 71 are inserted into these screw insertion holes 53a, respectively.

[0044] The portion of the stator holder 53 where the screw insertion hole 53a is provided is sandwiched between the first flange 22d of the motor housing 21 and the fourth flange 73c of the gear housing 71. In other words, the stator holder 53 is sandwiched between the motor housing 21 and the gear housing 71. Also, a pinion insertion hole 53b, through which the pinion gear 42 is inserted in a non-contact state, is provided in the approximate center of the stator holder 53.

[0045] [Base material] 4 and 6, a base member 60 made of a resin material such as plastic and formed in a generally crescent shape is attached to the inside of base mounting portion 23. A second sensor board fixing portion 61, partitioned by a generally rectangular wall portion, is provided integrally with base member 60 at approximately the center thereof, on the gear portion 70 side. A second sensor board SB2 is attached to the inside of second sensor board fixing portion 61, and second sensor board SB2 faces helical gear 78 in the axial direction of output shaft SH2.

[0046] Here, a single MR sensor MS is mounted on the second sensor board SB2, and the MR sensor MS faces a sensor magnet SM fixed to the rotation center of the helical gear 78 in the axial direction of the output shaft SH2. As a result, the on-board controller grasps the rotation state (rotation position, etc.) of the output shaft SH2 based on the detection signal (sine wave signal) from the MR sensor MS, and accurately controls the wiping position of the wiper member relative to the windshield.

[0047] An external connector (not shown) on the vehicle side can be electrically connected to each of the three-phase coils CL wound around the stator core 51, the first sensor board SB1, and the second sensor board SB2 via a connector connection section (not shown). This enables the on-board controller to drive the motor section 20 with high precision in response to detection signals from the first and second sensor boards SB1 and SB2.

[0048] [Gear section] 1, 3, 4, and 7, the gear portion 70 includes a gear housing 71 formed in a stepped, approximately dish-like shape by injection molding molten aluminum material or the like. The gear housing 71 includes a helical gear accommodating portion 72 and a stator holder covering portion 73, and the depth of the helical gear accommodating portion 72 is greater than the depth of the stator holder covering portion 73. Specifically, the depth of the helical gear accommodating portion 72 is approximately seven times the depth of the stator holder covering portion 73.

[0049] The helical gear accommodating portion 72 rotatably accommodates the helical gear 78 and has a third bottom wall 72a formed in a substantially disk shape and a third side wall 72b extending from the outer edge of the third bottom wall 72a in the axial direction of the output shaft SH2. A large-diameter boss portion 72c is integrally formed in the central portion of the third bottom wall 72a and protrudes outward from the helical gear accommodating portion 72 (upper side in FIG. 4). A cylindrical third bearing B3 that rotatably supports the output shaft SH2 is mounted radially inward of the large-diameter boss portion 72c. The output shaft SH2 is thus supported smoothly and rotatably by the large-diameter boss portion 72c that forms the gear housing 71 without any rattle.

[0050] Additionally, an O-ring 74 made of an elastic material such as rubber is attached to the radially inner side of the large diameter boss portion 72c and on the tip side (upper side in Figure 4) of the large diameter boss portion 72c, thereby preventing rainwater, dust, etc. from entering between the output shaft SH2 and the third bearing B3.

[0051] Furthermore, a plurality of reinforcing ribs 72d formed in a roughly triangular shape are integrally provided on the radially outer side of the large diameter boss portion 72c on the outer side of the gear housing 71. These reinforcing ribs 72d increase the fixing strength of the large diameter boss portion 72c to the third bottom wall 72a, and eight of them are arranged at equal intervals (45-degree intervals) around the circumference of the large diameter boss portion 72c.

[0052] A retaining ring 75 is fixed to the axial center of the output shaft SH2, and the retaining ring 75 is hooked onto the tip of the large diameter boss portion 72c. As a result, the large diameter boss portion 72c is sandwiched between the helical gear 78 and the retaining ring 75, and the output shaft SH2 is prevented from coming off the large diameter boss portion 72c. This reduces rattle of the output shaft SH2 relative to the large diameter boss portion 72c, thereby ensuring quietness of the wiper motor 10.

[0053] Additionally, two third flanges 72e are integrally formed on the outer edge of the third side wall 72b and protrude radially outward from the third side wall 72b. First fixing screws S1 (two of a total of five) for fixing the motor housing 21 to the gear housing 71 are screwed into the third flanges 72e, respectively.

[0054] Furthermore, the stator holder covering portion 73 includes a fourth bottom wall 73a formed in a generally crescent shape and a fourth side wall 73b extending from the outer edge of the fourth bottom wall 73a in the axial direction of the output shaft SH2. The stator holder covering portion 73 is a portion that covers the stator holder 53 (see FIG. 6) provided in the motor portion 20.

[0055] Additionally, a total of three fourth flanges 73c are integrally formed on the outer edge portion of the fourth bottom wall 73a and protrude radially outward from the fourth bottom wall 73a. First fixing screws S1 (three out of a total of five) for fixing the motor housing 21 to the gear housing 71 are screwed into the fourth flanges 73c, respectively.

[0056] Here, the gear housing 71 is provided with a second opening 76 that opens toward the motor housing 21. This second opening 76 faces the first opening 25 of the motor housing 21 (see FIG. 4). As shown in FIG. 7, when viewed in the axial direction of the output shaft SH2, the helical gear accommodating portion 72 and the stator holder covering portion 73 are partially overlapped with each other. As a result, the gear housing 71 has a generally pot-shaped luster when viewed in the axial direction of the output shaft SH2.

[0057] As shown in Fig. 4, a bearing member accommodating portion 72f is provided at a position eccentric from the large diameter boss portion 72c of the third bottom wall 72a. The radially inner side of the bearing member accommodating portion 72f is formed in a substantially cylindrical shape and is recessed toward the tip side of the output shaft SH2 (upper side in Fig. 4) inside the gear housing 71. A fourth bearing B4 that rotatably supports the tip side of the rotating shaft SH1 is accommodated inside the bearing member accommodating portion 72f.

[0058] In this way, the large diameter boss portion 72c that supports the output shaft SH2 and the fourth bearing B4 that supports the rotary shaft SH1 are each provided in the precisely formed aluminum gear housing 71. Therefore, the output shaft SH2 and the rotary shaft SH1 can be positioned with high precision, and the pinion gear 42 and the helical gear 78 can be meshed with high precision inside the gear housing 71. This makes it possible to further improve the quietness of the wiper motor 10.

[0059] In particular, both axial ends of the pinion gear 42 are rotatably supported by the second bearing B2 and the fourth bearing B4, which prevents deformation such as warping of the pinion gear 42. This effectively prevents the pinion gear 42 and the helical gear 78 from coming out of mesh.

[0060] A backup member accommodating portion 72g is provided in a portion of the third bottom wall 72a near the stator holder covering portion 73. The backup member accommodating portion 72g is disposed in the vicinity of the bearing member accommodating portion 72f. A backup member 77 is accommodated inside the backup member accommodating portion 72g.

[0061] The backup member 77 is made of a resin material such as plastic and is fixed inside the backup member housing portion 72g. The backup member 77 is disposed around the pinion gear 42 with a small gap between them. This prevents the pinion gear 42 from bending when a large external force is applied to the output shaft SH2. This also prevents the pinion gear 42 and the helical gear 78 from coming out of mesh.

[0062] Furthermore, a support protrusion 72h formed in a substantially annular shape is provided on the inner side of the third bottom wall 72a. The support protrusion 72h protrudes at a predetermined height toward the inside of the gear housing 71 (the lower side in FIG. 4). The support protrusion 72h prevents the helical gear 78 from tilting when a large external force is applied to the output shaft SH2. This prevents the helical gear 78 from tilting inside the gear housing 71, thereby maintaining the meshing between the pinion gear 42 and the helical gear 78. Specifically, the support protrusion 72h slidably supports a first side surface 78e (see FIG. 5) of the helical gear 78. This also enables the wiper motor 10 to operate smoothly, thereby improving the quietness of the wiper motor 10.

[0063] 7, the fourth bottom wall 73a is provided with a stator holder positioning recess 73d. The stator holder positioning recess 73d is provided so as to surround the periphery of the backup member accommodating portion 72g and is recessed toward the backup member accommodating portion 72g. The arc-shaped engagement protrusion 58 (see FIG. 6) of the stator holder 53 is fitted into the stator holder positioning recess 73d.

[0064] [bracket] 1 and 2, a bracket 80 for fixing the wiper motor 10 to the vehicle is fixed to the third bottom wall 72a of the gear housing 71. The bracket 80 is formed into a plate shape by punching a thick steel plate or the like. Specifically, the bracket 80 includes an annular bracket main body 81 fixed to the gear housing 71 and a total of three mounting legs 82 integrally provided on the outer edge of the bracket main body 81.

[0065] Furthermore, a substantially rectangular cutout 83 is provided on the radially inner side of the bracket main body 81. The cutout 83 is engaged with a rotating shaft support portion 79 provided on the gear housing 71. Here, the rotating shaft support portion 79 is disposed at a location where the bearing member accommodating portion 72f (see FIG. 4) is provided, and is formed in a substantially rectangular parallelepiped shape. This prevents the bracket 80 from rotating relative to the gear housing 71 when the bracket 80 is assembled to the gear housing 71, and ultimately allows the bracket 80 to be positioned with high precision relative to the gear housing 71 (improving assembly ease).

[0066] The bracket body 81 is firmly fixed to the third bottom wall 72a by a total of six fifth fixing screws S5. A rubber bushing (not shown) is attached to each mounting leg 82, and each rubber bushing is fixed to the vehicle by a fixing bolt (not shown). This makes it difficult for vibrations generated when the wiper motor 10 is operating to be transmitted to the vehicle, and also makes it difficult for vibrations from the vehicle to be transmitted to the wiper motor 10.

[0067] 1 and 2 is a mounting posture of the bracket 80 to the gear housing 71, for example, for a right-hand drive vehicle. In other words, the wiper motor 10 to which the bracket 80 is mounted in the posture shown in FIGS. 1 and 2 is a wiper motor 10 for a right-hand drive vehicle.

[0068] Here, in the wiper motor 10 of this embodiment, the bracket 80 can also be attached upside down to the gear housing 71. That is, the attachment posture of the bracket 80 to the gear housing 71 can be set to either a right-hand drive vehicle or a left-hand drive vehicle. In this way, in the wiper motor 10 of this embodiment, the front or back of the bracket 80 can be selected and fixed to the third bottom wall 72a, and one wiper motor 10 can be used for either a right-hand drive vehicle or a left-hand drive vehicle.

[0069] [Deceleration mechanism] 4 and 5, the reduction gear mechanism SD that forms the gear unit 70 is rotatably housed inside the gear housing 71. The reduction gear mechanism SD includes a pinion gear 42 that is integrally provided on the rotation shaft SH1, and a helical gear 78 that meshes with the pinion gear 42 and rotates at a slower speed than the pinion gear 42. Here, the helical gear 78 corresponds to the second gear in the present invention.

[0070] The axis of the pinion gear 42 and the axis of the helical gear 78 are parallel to each other. In other words, the rotation shaft SH1 and the output shaft SH2 are parallel to each other. This makes it possible for the reduction mechanism SD to be more compact in size than a worm reducer that includes a worm and a worm wheel whose axes intersect.

[0071] Furthermore, the pinion gear 42 is disposed on the rotation shaft SH1 side (input side) of the wiper motor 10, and the helical gear 78 is disposed on the output shaft SH2 side (output side) of the wiper motor 10. In other words, the speed reduction mechanism SD reduces the high-speed rotation of the pinion gear 42, which has a small number of teeth, to the low-speed rotation of the helical gear 78, which has a large number of teeth. Therefore, the helical gear 78 rotates at a slower speed than the pinion gear 42.

[0072] 5 and 6, helical teeth 42a are integrally formed on the periphery of the pinion gear 42, and the axial length of the helical teeth 42a is slightly longer than the axial length of the helical gear 78. This allows the helical teeth 42a to mesh securely with the helical gear 78.

[0073] The helical teeth 42a extend in a spiral pattern in the axial direction of the pinion gear 42, and the pinion gear 42 is provided with only one helical tooth 42a. In other words, the pinion gear 42 has one tooth. The helical tooth 42a is formed so that its cross section is circular, and is adapted to fit into (mesh with) the meshing recess 78d of the helical gear 78. In this way, by providing the pinion gear 42 with one tooth, the gear transmission efficiency is improved, thereby achieving power savings in the motor unit 20.

[0074] The helical gear 78 that forms the reduction gear mechanism SD is made of a resin material such as plastic. As shown in Figures 5 and 7, the helical gear 78 has a gear body 78a formed in a substantially disk shape, and is firmly fixed so that the rotation center of the gear body 78a coincides with the rotation center of the output shaft SH2. This causes the output shaft SH2 to rotate together with the helical gear 78. In addition, a sensor magnet SM is fixed to the rotation center of the gear body 78a on the side of the second sensor board SB2 (the lower side in Figure 5).

[0075] Here, the output shaft SH2 is formed with a step by cutting a round steel bar, and an output part OP is integrally provided at the tip end in the axial direction thereof to which a link mechanism (not shown) forming a wiper member is fixed. Specifically, the output part OP has a male thread (not shown in detail), and a nut (not shown) for fixing the link mechanism is screwed to the output part OP.

[0076] A gear forming portion 78b formed in a generally cylindrical shape is provided on the radially outer side of the gear main body 78a. A plurality of helical teeth 78c are provided on the gear forming portion 78b and aligned in the circumferential direction. These helical teeth 78c are inclined at a predetermined angle with respect to the axial direction of the helical gear 78, thereby rotating the helical gear 78 in conjunction with the rotation of the helical teeth 42a. Specifically, meshing recesses 78d are provided between adjacent helical teeth 78c, and the helical teeth 42a fit into and mesh with the meshing recesses 78d. The meshing recesses 78d are also formed to have a circular cross-sectional shape.

[0077] A first side surface 78e and a second side surface 78f are provided on both axial sides of the gear forming portion 78b. The first side surface 78e faces the support protrusions 72h (see FIG. 4) of the helical gear accommodating portion 72 in the axial direction of the output shaft SH2. The second side surface 78f faces the pair of arc-shaped support protrusions 57 (see FIG. 6) of the stator holder 53 in the axial direction of the output shaft SH2. This prevents the helical gear 78 from tilting when a large external force is applied to the output shaft SH2.

[0078] Here, the number of helical teeth 78c (meshing recesses 78d) provided on the helical gear 78 is 45, and in this embodiment, the reduction ratio of the reduction mechanism SD consisting of the pinion gear 42 and the helical gear 78 is 45. In other words, 45 rotations of the pinion gear 42 result in the helical gear 78 finally rotating once. In this way, compared to conventional worm reducers, the size can be made more compact and a large reduction ratio can be obtained. However, the number of helical teeth 78c (meshing recesses 78d) provided on the helical gear 78 is not limited to 45 as described above, and may be set to, for example, 40 or another number depending on the specifications of the reduction mechanism SD.

[0079] As described above in detail, according to this embodiment, since the rotary shaft SH1 and the output shaft SH2 are parallel to each other, the motor housing 21 and the gear housing 71 can be arranged in the axial direction of the rotary shaft SH1 (output shaft SH2), as shown in FIG. 4. This allows the exterior of the wiper motor 10 to be symmetrical about the line segment CT connecting the rotary shaft SH1 and the output shaft SH2. Therefore, there is no need for any mounting directionality on the left or right side of the line segment CT connecting the rotary shaft SH1 and the output shaft SH2. This allows for improved layout flexibility.

[0080] Furthermore, according to this embodiment, the rotor body 41 has a rotor opening 41d that opens toward the gear housing 71 on the axial side opposite to the side where the rotor bottom wall 41a is provided. This allows the stator core 51 that forms the stator unit 50 to be disposed radially inward of the rotor side wall 41b from the rotor opening 41d. This allows the size of the wiper motor 10 to be reduced in the axial direction of the rotating shaft SH1. Furthermore, the magnet MG fixed to the radially inner side of the rotor side wall 41b and the Hall sensor HS supported by the stator holder 53 can face each other without any intervening element. This allows the detection accuracy of the Hall sensor HS to be improved.

[0081] Furthermore, according to this embodiment, the motor housing 21 has a first opening 25 that opens toward the gear housing 71, and at least a portion of the first opening 25 is covered by a stator holder 53 that holds the stator core 51. The stator holder 53 is provided with a Hall sensor HS that faces the magnet MG in the axial direction of the rotation shaft SH1. In this way, since both the stator core 51 and the Hall sensor HS are provided on the stator holder 53, assembly can be improved while increasing the positional accuracy of both. This also improves the detection accuracy of the Hall sensor HS. Furthermore, since a sensor magnet dedicated to rotation detection is not required, the number of parts in the wiper motor 10 can be reduced, allowing for further miniaturization and weight reduction.

[0082] Furthermore, according to the present embodiment, the stator holder 53 is sandwiched between the motor housing 21 and the gear housing 71, and therefore can be fixed simply by sandwiching the stator holder 53. Therefore, there is no need to provide a separate fixing structure for fixing the stator holder 53, and the assembly of the wiper motor 10 can be improved.

[0083] Furthermore, according to the present embodiment, the reduction gear mechanism SD is formed by the pinion gear 42 having one spiral tooth 42a connected in a spiral shape, and the helical gear 78 having the helical tooth 78c with which the one spiral tooth 42a meshes, which makes it possible to improve the gear transmission efficiency and achieve power saving in the motor unit 20. Also, compared to a worm reducer, it is possible to increase the reduction ratio while reducing the size thereof.

[0084] Furthermore, according to this embodiment, the wiper motor 10 is standardized for both right-hand drive vehicles and left-hand drive vehicles, eliminating the need to manufacture separate motors for the left and right sides, and the number of parts can be reduced, thereby saving energy required to manufacture the wiper motor 10. This makes it possible to achieve the Sustainable Development Goals (SDGs) established by the United Nations, particularly Goal 7 (Ensure access to affordable, reliable, sustainable and modern energy for all) and Goal 13 (Take urgent action to combat climate change and its impacts).

[0085] The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit and scope of the present invention. For example, in the above-described embodiment, a brushless motor is applied to a drive source (wiper motor 10) of a wiper device mounted on a vehicle, but the present invention is not limited to this, and can be applied to other drive sources such as a power window device and a sunroof device.

[0086] Furthermore, in the above embodiment, the gear portion 70 and the bracket 80 having the mounting legs 82 are shown as separate entities, but the present invention is not limited to this, and the bracket 80 may be omitted and the mounting legs may be integrally formed on the gear housing 71 that forms the gear portion 70.

[0087] Furthermore, the material, shape, size, number, installation location, etc. of each component in the above-described embodiments are arbitrary as long as they can achieve the present invention, and are not limited to the above-described embodiments. [Explanation of symbols]

[0088] 10: wiper motor (brushless motor), 20: motor section, 21: motor housing, 22: motor accommodating section, 22a: first bottom wall, 22b: first side wall, 22c: small diameter step section, 22d: first flange, 23: base mounting section, 23a: second bottom wall, 23b: second side wall, 23c: second flange, 24: retaining member, 25: first opening (motor opening), 30: brushless motor, 40: rotor unit, 41: rotor body (rotor), 41a: rotor bottom wall (bottom wall), 41b: rotor side wall (side wall), 41c: small diameter boss section, 41d: rotor : Pinion gear (first gear), 42a: Spiral teeth (teeth), 50: Stator unit, 51: Stator core (stator), 51a: Core body, 51b: Teeth, 52: Insulator, 53: Stator holder (stator bracket), 53a: Insertion hole, 53b: Pinion insertion hole, 54: Bearing holding portion, 55: Bearing fixing member, 56: First sensor board fixing portion, 57: Arc-shaped support protrusion, 58: Arc-shaped engagement protrusion, 60: Base member, 61: Second sensor board fixing portion, 70: Gear portion, 71: Gear housing, 72: Helix Helical gear accommodating portion, 72a: third bottom wall, 72b: third side wall, 72c: large diameter boss portion, 72d: reinforcing rib, 72e: third flange, 72f: bearing member accommodating portion, 72g: backup member accommodating portion, 72h: support protrusion, 73: stator holder covering portion, 73a: fourth bottom wall, 73b: fourth side wall, 73c: fourth flange, 73d: stator holder positioning recess, 74: O-ring, 75: retaining ring, 76: second opening, 77: backup member, 78: helical gear (second gear), 78a: gear body, 78b: gear forming portion, 78c: helical teeth, 78 d: meshing recess, 78e: first side surface, 78f: second side surface, 79: rotating shaft support portion, 80: bracket, 81: bracket body, 82: mounting leg, 83: notch, B1: first bearing, B2: second bearing, B3: third bearing, B4: fourth bearing, CL: coil, CT: line segment, HS: hall sensor (magnetic sensor), MG: magnet, MS: MR sensor, OP: output portion, SB1: first sensor board, SB2: second sensor board, SD: reduction mechanism, SF1: first surface, SF2: second surface, SH1: rotating shaft, SH2: output shaft, SM: sensor magnet

Claims

1. A brushless motor having a motor section and a gear section, The motor unit includes: a rotating shaft having a first gear provided at its tip end; a rotor having a bottom wall and a side wall, the bottom wall being fixed to a base end side of the rotary shaft; a plurality of magnets fixed to the side wall and arranged in a circumferential direction of the rotor; a stator provided between the rotating shaft and the magnet in a radial direction of the rotor and having a coil wound thereon; a motor housing that rotatably supports the rotary shaft and accommodates the rotor and the stator; Equipped with The gear portion is a second gear meshed with the first gear; an output shaft having an output portion provided at a tip end side, a base end side fixed to the second gear, and being parallel to the rotation shaft; a gear housing that rotatably supports the output shaft and accommodates the second gear; It is equipped with the motor housing has a motor opening that opens toward the gear housing, At least a portion of the motor opening is covered by a stator bracket that holds the stator, a magnetic sensor provided on the stator bracket, the magnetic sensor facing the magnet in the axial direction of the rotation shaft; Brushless motor.

2. 2. The brushless motor according to claim 1, The rotor has a rotor opening that opens toward the gear housing on the side opposite to the side on which the bottom wall is provided in the axial direction. Brushless motor.

3. The stator bracket is sandwiched between the motor housing and the gear housing.

2. The brushless motor according to claim 1.

4. the first gear is a pinion gear having one spirally connected tooth, the second gear is a helical gear having helical teeth with which the teeth mesh; 2. The brushless motor according to claim 1.

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