Speed ​​reduction mechanism and motor with speed reduction mechanism

Abstract

This invention provides a speed reduction mechanism and a motor with a speed reduction mechanism. The first gear and the second gear can be configured with an arc-shaped, uneven meshing structure that does not deteriorate the meshing state between them. Furthermore, the number of teeth on the first gear can be set to one, and the number of teeth on the second gear can be increased to easily increase the tooth difference. A helical meshing protrusion (31c) is provided on the pinion (31), and multiple meshing recesses (32d) for the meshing protrusion to mesh on the helical gear (32). These meshing protrusions and recesses are formed in an arc shape in a direction orthogonal to the axial direction of the pinion. Therefore, the pinion and helical gear can be configured with an arc-shaped, uneven meshing structure that does not deteriorate the meshing state between them, and the number of teeth on the pinion can be set to one, and the number of teeth on the helical gear can be increased to easily increase the tooth difference. Therefore, the reduction ratio can be further increased without increasing the volume of the speed reduction mechanism (30).

Description

[0001] This application is a divisional application of the original application, application number 201980019815.5, filed on April 3, 2019, entitled "Speed ​​Reduction Mechanism and Motor with Speed ​​Reduction Mechanism". Technical Field

[0002] The present invention relates to a speed reduction mechanism and a motor with the speed reduction mechanism, the speed reduction mechanism comprising a first gear and a second gear meshing with each other. Background Technology

[0003] Previously, the drive source for windshield wiper devices or power window devices installed in automobiles and other vehicles was a small motor with a reduction gear that could produce a large output. Such a motor with a reduction gear for vehicle use is described, for example, in Patent Document 1.

[0004] The motor with a reduction mechanism described in Patent Document 1 is a drive source for a seat lifter device, including an electric motor and a housing. Furthermore, inside the housing, a small-tooth helical gear that rotates via the rotating shaft of the electric motor, a driven helical gear meshing with the small-tooth helical gear, a worm that rotates integrally with the driven helical gear, and a worm wheel meshing with the worm are rotatably housed.

[0005] Thus, in the motor with a reduction mechanism described in Patent Document 1, a two-stage reduction mechanism is housed inside the casing. Specifically, the first-stage reduction mechanism consists of a small-tooth-count helical gear and a driven helical gear, while the second-stage reduction mechanism consists of a worm and a worm wheel. Therefore, the motor with the reduction mechanism can be made compact and placed next to a seat.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2017-133582 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] However, in the technology described in Patent Document 1, for example, involute gears are used for the small-tooth-count helical gear and the driven helical gear constituting the first-stage reduction mechanism. Therefore, when it is necessary to further increase the reduction ratio, the following undesirable situation may occur.

[0011] That is, in order to further increase the reduction ratio, it is necessary to increase the difference in the number of teeth between the small-tooth-count helical gear and the driven helical gear. However, the small-tooth-count helical gear has only 2 teeth, which is already a small number. Therefore, if we consider increasing the number of teeth on the driven helical gear, then the adjacent teeth of the driven helical gear will be arranged close to each other, and the meshing surface of the teeth will be raised approximately vertically to form a planar shape.

[0012] This leads to the problem that the teeth of the small-tooth-count helical gear interfere with each other, resulting in a deterioration of the meshing state. Thus, for involute gears, there is a limit to the need to further increase the reduction ratio without increasing the size of the reduction mechanism.

[0013] The purpose of this invention is to provide a speed reduction mechanism and a motor with the speed reduction mechanism, wherein the speed reduction mechanism includes gears of a meshing shape that can further increase the speed reduction ratio.

[0014] Technical means to solve the problem

[0015] The deceleration mechanism of the present invention includes a first gear and a second gear, and has: a first tooth portion disposed on the first gear and extending spirally along the axial direction of the first gear; an engagement protrusion disposed on the first tooth portion and formed in an arc shape in a direction orthogonal to the axial direction of the first gear, and having a curvature center at a position eccentric from the rotation center of the first gear; a plurality of second teeth portions disposed on the second gear, inclined relative to the axial direction of the first gear and arranged along the circumferential direction of the second gear; and an engagement recess disposed between adjacent second teeth portions and formed in an arc shape in a direction orthogonal to the axial direction of the first gear for engagement by the engagement protrusion.

[0016] In other embodiments of the present invention, the reduction ratio of the first gear and the second gear is equal to the ratio of the first distance to the second distance, wherein the first distance is the distance between the curvature center of the meshing protrusion and the rotation center of the first gear, and the second distance is the distance between the curvature center of the meshing recess and the rotation center of the second gear.

[0017] In other embodiments of the present invention, the first tooth portion includes: a vertex, located at the end of the first gear on the radially outer side, disposed on the meshing protrusion; and a clearance portion, located at the end opposite to the vertex relative to the center of curvature of the meshing protrusion, to prevent interference with the second tooth portion.

[0018] In other embodiments of the present invention, the axis of the first gear is parallel to the axis of the second gear.

[0019] The motor with a reduction mechanism of the present invention includes: a motor having a rotating body; a first gear rotating via the rotating body; and a second gear rotating via the first gear. The motor with the reduction mechanism has: a first tooth portion disposed on the first gear and extending helically along the axial direction of the first gear; an engagement protrusion disposed on the first tooth portion, formed in an arc shape in a direction orthogonal to the axial direction of the first gear, and having a curvature center at a position eccentric from the rotation center of the first gear; a plurality of second teeth portions disposed on the second gear, inclined relative to the axial direction of the first gear, and arranged along the circumferential direction of the second gear; engagement recesses disposed between adjacent second teeth portions, formed in an arc shape in a direction orthogonal to the axial direction of the first gear, for engagement by the engagement protrusion; and an output shaft disposed at the rotation center of the second gear.

[0020] In other embodiments of the present invention, the reduction ratio of the first gear and the second gear is equal to the ratio of the first distance to the second distance, wherein the first distance is the distance between the curvature center of the meshing protrusion and the rotation center of the first gear, and the second distance is the distance between the curvature center of the meshing recess and the rotation center of the second gear.

[0021] In other embodiments of the present invention, the first tooth includes: a vertex, located at the end of the first gear on the radially outer side, disposed on the meshing protrusion; and a clearance portion, disposed at the end opposite to the vertex relative to the center of curvature of the meshing protrusion, to prevent interference with the second tooth.

[0022] In other embodiments of the present invention, the axis of the first gear is parallel to the axis of the second gear.

[0023] The deceleration mechanism of the present invention includes a first gear and a second gear, and has: a meshing protrusion disposed on the first gear and formed into an arc shape with a first radius of curvature along the rotation direction of the first gear; and a meshing recess disposed on the second gear for meshing with the meshing protrusion, the meshing recess including: a bottom disposed at the center of the meshing recess along the rotation direction of the second gear; and sidewall portions disposed on both sides of the bottom along the rotation direction of the second gear, the sidewall portions being arc-shaped recesses or protrusions with a second radius of curvature larger than the first radius of curvature.

[0024] In other embodiments of the present invention, the size of the second radius of curvature is at least twice the size of the first radius of curvature.

[0025] In other embodiments of the present invention, a lubricating oil retaining portion is provided between the engaging protrusion and the bottom, the lubricating oil retaining portion retaining lubricating oil.

[0026] In other embodiments of the present invention, an accumulation portion is provided between the engagement protrusion and the bottom, the accumulation portion narrowing the gap formed between the engagement protrusion and the bottom.

[0027] Another embodiment of the present invention is a speed reduction mechanism, including a first gear and a second gear, and having: an engagement protrusion disposed on the first gear and formed in an arc shape along the rotation direction of the first gear; and an engagement recess disposed on the second gear for engagement of the engagement protrusion, the engagement recess including: a bottom disposed at the center of the engagement recess along the rotation direction of the second gear; and sidewalls disposed on both sides of the bottom along the rotation direction of the second gear, the sidewalls being planes extending straight from the bottom.

[0028] In other embodiments of the present invention, a lubricating oil retaining portion is provided between the engaging protrusion and the bottom, the lubricating oil retaining portion retaining lubricating oil.

[0029] In other embodiments of the present invention, an accumulation portion is provided between the engagement protrusion and the bottom, the accumulation portion narrowing the gap formed between the engagement protrusion and the bottom.

[0030] The motor with a reduction mechanism of the present invention has a reduction mechanism including a first gear and a second gear, and includes a rotating shaft for rotating the first gear. The motor with the reduction mechanism has: a meshing protrusion disposed on the first gear and formed into an arc shape with a first radius of curvature along the rotation direction of the first gear; and a meshing recess disposed on the second gear for meshing with the meshing protrusion. The meshing recess includes: a bottom disposed at the center of the meshing recess along the rotation direction of the second gear; and sidewalls disposed on both sides of the bottom along the rotation direction of the second gear. The sidewalls are arc-shaped recesses or protrusions with a second radius of curvature larger than the first radius of curvature.

[0031] In other embodiments of the present invention, the size of the second radius of curvature is at least twice the size of the first radius of curvature.

[0032] In other embodiments of the present invention, a lubricating oil retaining portion is provided between the engaging protrusion and the bottom, the lubricating oil retaining portion retaining lubricating oil.

[0033] In other embodiments of the present invention, an accumulation portion is provided between the engagement protrusion and the bottom, the accumulation portion narrowing the gap formed between the engagement protrusion and the bottom.

[0034] Another embodiment of the present invention is a motor with a reduction mechanism, having a reduction mechanism including a first gear and a second gear, and including a rotating shaft for rotating the first gear. The motor with the reduction mechanism has: an engagement protrusion disposed on the first gear and formed in an arc shape along the rotation direction of the first gear; and an engagement recess disposed on the second gear for engagement of the engagement protrusion. The engagement recess includes: a bottom disposed at the center of the engagement recess along the rotation direction of the second gear; and sidewalls disposed on both sides of the bottom along the rotation direction of the second gear, the sidewalls being planes extending straight from the bottom.

[0035] In other embodiments of the present invention, a lubricating oil retaining portion is provided between the engaging protrusion and the bottom, the lubricating oil retaining portion retaining lubricating oil.

[0036] In other embodiments of the present invention, an accumulation portion is provided between the engagement protrusion and the bottom, the accumulation portion narrowing the gap formed between the engagement protrusion and the bottom.

[0037] The effects of the invention

[0038] According to the present invention, a spiral meshing protrusion is provided on the first gear, and a plurality of meshing recesses are provided on the second gear for meshing of the meshing protrusion, wherein the meshing protrusion and meshing recesses are formed in an arc shape in a direction orthogonal to the axial direction of the first gear.

[0039] Therefore, the first and second gears can be designed with an arc-shaped, uneven meshing structure that will not deteriorate the meshing state between them. Furthermore, the number of teeth on the first gear can be set to one, and the number of teeth on the second gear can be increased to easily increase the tooth difference. Thus, the reduction ratio can be further increased without increasing the volume of the reduction mechanism. Attached Figure Description

[0040] Figure 1 A perspective view of a motor with a speed reduction mechanism, viewed from the side of the connector connection.

[0041] Figure 2 A perspective view of a motor with a reduction gear mechanism, viewed from the output shaft side.

[0042] Figure 3 A perspective view illustrating the internal structure of a motor with a speed reduction mechanism.

[0043] Figure 4 This is a magnified three-dimensional view of the meshing part of the pinion and helical gear.

[0044] Figure 5 For along Figure 4 A cross-sectional view of line AA.

[0045] Figure 6 Explanatory diagrams illustrating the detailed shapes of pinions and helical gears.

[0046] Figure 7 An explanatory diagram illustrating the meshing action of a pinion and a helical gear.

[0047] Figure 8 To indicate the relationship between implementation method 2 and Figure 5 The corresponding diagram.

[0048] Figure 9 To indicate the relationship between implementation method 3 and Figure 5 The corresponding diagram.

[0049] Figure 10 To represent the implementation method 4 and Figure 5 The corresponding diagram.

[0050] Figure 11 To indicate the relationship between implementation method 5 and Figure 5 The corresponding diagram.

[0051] Figure 12 An explanatory diagram illustrating embodiment 6 (face gear).

[0052] Figure 13 This is an explanatory diagram illustrating embodiment 7 (herringbone gear).

[0053] Figure 14 A perspective view of a motor with a speed reduction mechanism, viewed from the side of the connector connection.

[0054] Figure 15 A perspective view of a motor with a reduction gear mechanism, viewed from the output shaft side.

[0055] Figure 16 A perspective view illustrating the internal structure of a motor with a speed reduction mechanism.

[0056] Figure 17 This is a magnified three-dimensional view of the meshing part of the pinion and helical gear.

[0057] Figure 18 For along Figure 17 A cross-sectional view of line A1-A1.

[0058] Figure 19 This is an explanatory diagram illustrating the changes in the inter-core pitch offset, pressure angle, and backlash in Embodiment 8.

[0059] Figure 20 This is an explanatory diagram illustrating the changes in inter-core pitch offset, pressure angle, and backlash in the comparative example.

[0060] Figure 21 A graph comparing the changes in tooth clearance in Embodiment 8 and the comparative example.

[0061] Figure 22 A graph comparing the changes in pressure angle between Embodiment 8 and the comparative example.

[0062] Figure 23 To indicate the relationship between implementation method 9 and Figure 18 The corresponding diagram.

[0063] Figure 24 To indicate the relationship between implementation method 10 and Figure 18 The corresponding diagram.

[0064] Figure 25 To indicate the relationship between implementation method 11 and Figure 18 The corresponding diagram.

[0065] Figure 26 A graph showing the relationship between the tooth diameter ratio and the backlash deviation in Embodiments 8, 10, and 11.

[0066] Figure 27 A graph showing the relationship between the tooth diameter ratio and the pressure angle of Embodiment 8, Embodiment 10, and the involute gear.

[0067] Figure 28 A graph showing the change in the offset of the core pitch and the pressure angle of Embodiments 8, 10, and 11 and the involute gear.

[0068] Figure 29 A perspective view of a motor with a speed reduction mechanism, viewed from the side of the connector connection.

[0069] Figure 30 A body view of a motor with a reduction gear mechanism, viewed from the output shaft side.

[0070] Figure 31 An exploded perspective view illustrating the internal structure of a motor with a speed reduction mechanism.

[0071] Figure 32 A cross-sectional view illustrating the internal structure of a motor with a speed reduction mechanism.

[0072] Figure 33 of (a), Figure 33 (b) is a three-dimensional view of the gearbox in the form of a single unit.

[0073] Figure 34 An explanatory diagram illustrating the manufacturing sequence of a gearbox.

[0074] Figure 35 An enlarged cross-sectional view for illustrating the details of the sensor substrate.

[0075] Figure 36 This is an enlarged cross-sectional view of a brushless motor.

[0076] Figure 37 For along Figure 36 A cross-sectional view of line A2-A2.

[0077] Figure 38 A perspective view illustrating the details of the speed reduction mechanism. Detailed Implementation

[0078] Hereinafter, Embodiment 1 of the present invention will be described in detail with reference to the accompanying drawings.

[0079] Figure 1 This is a perspective view of a motor with a speed reduction mechanism, viewed from the side of the connector connection. Figure 2 This is a perspective view of a motor with a reduction gear mechanism, viewed from the output shaft side. Figure 3 A perspective view illustrating the internal structure of a motor with a speed reduction mechanism. Figure 4 This is a magnified three-dimensional diagram showing the meshing part of the pinion and helical gear. Figure 5 Indicates along Figure 4 Cross-sectional view of line AA Figure 6 Explanatory diagrams showing the detailed shapes of pinions and helical gears. Figure 7 An explanatory diagram illustrating the meshing action of a pinion and a helical gear.

[0080] Figure 1 and Figure 2 The motor 10 with a reduction gear shown can be used, for example, as a drive source for a windshield wiper unit (not shown) mounted on a vehicle such as an automobile. More specifically, the motor 10 with the reduction gear is disposed on the front side of the windshield (not shown) and causes the windshield wiper member (not shown), which is oscillating freely on the windshield, to oscillate within a predetermined wiping range (between the downward reversing position and the upward reversing position).

[0081] The motor 10 with a reduction gear includes a housing 11 forming its outer contour. Additionally, as... Figure 3 As shown, a brushless motor 20 and a reduction gear 30 are rotatably housed inside the casing 11. Here, the casing 11 is formed by an aluminum casing 12 and a plastic cover member 13.

[0082] like Figure 1 and Figure 2As shown, the shell 12 is formed into a generally bowl-shaped form by injection molding molten aluminum material. Specifically, the shell 12 includes a bottom wall portion 12a, a side wall portion 12b integrally formed around it, and a shell flange 12c provided on the opening side (left side in the figure) of the shell 12.

[0083] At approximately the center of the bottom wall portion 12a, a cylindrical support portion 12d is integrally provided to rotatably hold the output shaft 34. On the radially inner side of the support portion 12d, a cylindrical bearing member (not shown), referred to as a sliding bearing, is installed, thereby allowing the output shaft 34 to rotate smoothly relative to the support portion 12d without wobbling.

[0084] Furthermore, a plurality of reinforcing ribs 12e are integrally provided on the radially outer side of the support portion 12d, extending radially from the support portion 12d as the center. These reinforcing ribs 12e are disposed between the support portion 12d and the bottom wall portion 12a, and are generally triangular in shape. These reinforcing ribs 12e improve the fixing strength of the support portion 12d to the bottom wall portion 12a, and prevent undesirable conditions such as the support portion 12d tilting relative to the bottom wall portion 12a.

[0085] Furthermore, a bearing component receiving portion 12f is integrally provided at a position eccentric to the support portion 12d on the bottom wall portion 12a. The bearing component receiving portion 12f is formed as a bottomed cylindrical shape and protrudes in the same direction as the protruding direction of the support portion 12d. Additionally, as... Figure 3 As shown, inside the bearing component housing 12f, a ball bearing 33 that rotatably supports the front end of the pinion 31 is housed.

[0086] In addition, such as Figure 2 As shown, a retaining ring 12g is provided between the support portion 12d and the output shaft 34, thereby preventing the output shaft 34 from axially wobbling in the support portion 12d. This ensures the quiet operation of the motor 10 with the reduction gear mechanism.

[0087] The cover member 13 forming the housing 11 is formed into a generally flat plate shape by injection molding molten plastic material. Specifically, the cover member 13 includes a body portion 13a and a cover flange 13b integrally disposed around it. In addition, the cover flange 13b abuts against the housing flange 12c via a sealing member (not shown) such as an O-ring. This prevents rainwater and the like from entering the housing 11.

[0088] Furthermore, a brushless motor 20 is integrally housed in the main body 13a of the cover member 13 (see reference). Figure 3The motor housing 13c is formed as a bottomed cylindrical section and protrudes to the side opposite to the housing 12. With the cover member 13 installed on the housing 12, the motor housing 13c faces the bearing member housing 12f of the housing 12. Furthermore, the stator 21 of the brushless motor 20 (see reference 12f) is fixed inside the motor housing 13c. Figure 3 ).

[0089] Furthermore, a connector connection portion 13d is integrally provided on the body portion 13a of the cover member 13 for connection to an external connector (not shown) on the vehicle side. Inside the connector connection portion 13d, multiple terminal members 13e (for supplying drive current to the brushless motor 20) are located. Figure 1 Only one end of the brushless motor 20 is shown in the diagram. Additionally, drive current is supplied from an external connector to the brushless motor 20 via these terminal members 13e.

[0090] Furthermore, a control board (not shown) is provided between the other end of the plurality of terminal members 13e and the brushless motor 20 to control the rotation state (speed or direction of rotation, etc.) of the brushless motor 20. As a result, the wiper member fixed to the front end of the output shaft 34 swings within a predetermined wiping range on the windshield. Additionally, the control board is fixed to the inside of the body portion 13a of the cover member 13.

[0091] like Figure 3 As shown, the brushless motor 20 housed inside the housing 11 includes an annular stator 21. The stator 21 is fixed to the motor housing portion 13c of the cover member 13 in an anti-rotation state (see reference). Figure 1 (the interior of)

[0092] The stator 21 is formed by stacking multiple thin steel plates (magnetic bodies), and has multiple teeth (not shown) on its radially inner side. Furthermore, multiple turns of U-phase, V-phase, and W-phase coils 21a are wound around these teeth using methods such as concentrated winding. Thus, by alternately supplying drive current to each coil 21a at predetermined times, the rotor 22, located radially inner side of the stator 21, is rotated in a predetermined direction with a predetermined drive torque.

[0093] A rotor 22 is provided radially inside the stator 21, rotating freely with a small gap (air gap). The rotor 22 constitutes the rotating body of the present invention, comprising a rotor body 22a formed by stacking multiple thin steel plates (magnetic bodies) into a generally cylindrical shape. Furthermore, a cylindrical permanent magnet 22b is provided on the outer periphery of the rotor 22. Here, the permanent magnet 22b is magnetized such that its magnetic poles are alternately arranged along its circumference as N poles, S poles, etc. The permanent magnet 22b is also securely fixed to the rotor body 22a in a rotatable manner using adhesives or the like.

[0094] Thus, the brushless motor 20 of this embodiment becomes a brushless motor with a surface permanent magnet (SPM) structure, in which permanent magnets 22b are fixed on the surface of the rotor body 22a. However, it is not limited to a brushless motor with an SPM structure; a brushless motor with an interior permanent magnet (IPM) structure, in which multiple permanent magnets are embedded in the rotor body 22a, may also be used.

[0095] Furthermore, instead of a single cylindrical permanent magnet 22b, multiple permanent magnets with cross-sections formed in a generally arc shape along the direction intersecting the axis of the rotor body 22a can be arranged at equal intervals along the circumference of the rotor body 22a in an alternating manner with alternating magnetic poles. Moreover, the number of poles of the permanent magnet 22b can be arbitrarily set to two poles or more, depending on the specifications of the brushless motor 20.

[0096] like Figure 3 As shown, the reduction mechanism 30 housed inside the casing 11 includes a pinion (first gear) 31 formed in a generally rod shape and a helical gear (second gear) 32 formed in a generally disk shape. Here, the axes of the pinion 31 and the helical gear 32 are parallel to each other. Thus, compared with a worm gear reducer that includes a worm and a worm wheel with intersecting axes, the reduction mechanism 30 can be made more compact.

[0097] Furthermore, the pinion 31 is disposed on the input side (drive source side) of the motor 10 with the reduction mechanism, and the helical gear 32 is disposed on the output side (drive object side) of the motor 10 with the reduction mechanism. That is, the reduction mechanism 30 reduces the high-speed rotation of the pinion 31 with fewer teeth to the low-speed rotation of the helical gear 32 with more teeth.

[0098] Here, the base end of the pinion 31 is firmly fixed to the rotation center of the rotor body 22a by pressing or the like, and the pinion 31 rotates integrally with the rotor body 22a. That is, the pinion 31 rotates via the rotor 22. Furthermore, the front end of the pinion 31 is rotatably supported by a ball bearing 33. Additionally, at the rotation center of the helical gear 32, the base end of the output shaft 34 is firmly fixed by pressing or the like, and the output shaft 34 rotates integrally with the helical gear 32.

[0099] The pinion 31 forming the reduction mechanism 30 is made of metal and is in the shape of... Figures 3 to 6As shown in the diagram. Specifically, the pinion 31 has a pinion body 31a that is formed into a generally cylindrical shape, with its axial base end fixed to the rotor body 22a and its axial front end rotatably supported by the ball bearing 33. That is, the rotation center C1 of the pinion 31 (pinion body 31a) coincides with the rotation center of the rotor body 22a and the ball bearing 33.

[0100] On the axial portion of the pinion body 31a facing the helical gear 32, a helical tooth (first tooth portion) 31b is integrally provided. Specifically, the axial length of the helical tooth 31b is set to be slightly longer than the axial length of the helical gear 32. Therefore, the helical tooth 31b can reliably mesh with the helical gear 32. Furthermore, the helical tooth 31b extends continuously in a helical shape along the axial direction of the pinion 31, and only one helical tooth 31b is provided on the pinion 31. That is, the number of teeth on the pinion 31 is set to "1".

[0101] like Figure 5 As shown, the helical tooth 31b is formed with a circular cross-section along a direction orthogonal to the axis of the pinion 31. Furthermore, the center C2 of the helical tooth 31b is eccentric (offset) by a predetermined distance L relative to the rotation center C1 of the pinion 31. That is, the eccentricity of the center C2 relative to the rotation center C1 is L. Therefore, as the pinion 31 rotates, the center C2 of the helical tooth 31b follows the first rotational trajectory OC. In other words, the first rotational trajectory OC forms the reference circle of the helical tooth 31b.

[0102] Moreover, such as Figure 5 As shown, if an auxiliary line AL is drawn from the rotation center C1 of the pinion 31 to the center C2 (downwards in the figure) of the helical tooth 31b, and the auxiliary line AL is further extended to the surface of the helical tooth 31b, then the auxiliary line AL intersects the surface of the helical tooth 31b. The point of intersection becomes the vertex BP of the meshing protrusion 31c. Here, the vertex BP is located at the radially outer end (surface) of the pinion 31, on the meshing protrusion 31c. Furthermore, the meshing protrusion 31c constitutes a meshing portion as part of the helical tooth 31b, and the meshing protrusion 31c is also helical, entering (meshing into) the meshing recess 32d between adjacent helical teeth 32c of the helical gear 32.

[0103] Thus, the meshing protrusion 31c is provided on the portion of the helical tooth 31b near the apex BP. Furthermore, the meshing protrusion 31c is formed in an arc shape in a direction orthogonal to the axial direction of the pinion 31, and has a curvature center C2 located eccentrically at a predetermined distance L from the rotation center C1 of the pinion 31. That is, the curvature center C2 of the meshing protrusion 31c coincides with the center C2 of the helical tooth 31b.

[0104] Here, as the pinion 31 rotates, the apex BP of the meshing protrusion 31c follows the second rotation trajectory PR. That is, the diameter D1 of the second rotation trajectory PR is greater than the diameter D2 of the helical tooth 31b (D1 > D2).

[0105] also, Figure 5 In the figure, it indicates the state in which the vertex BP of the meshing protrusion 31c enters the meshing recess 32d of the helical gear 32, that is, it indicates the state in which the meshing protrusion 31c and the meshing recess 32d mesh with each other.

[0106] The helical gear 32 forming the reduction mechanism 30 is made of plastic and is in the shape of... Figures 3 to 6 The shape is as shown. Specifically, the helical gear 32 includes a gear body 32a formed in a generally disc shape, and the base end side of the output shaft 34 is firmly fixed to the center portion of the gear body 32a by pressing or the like. Moreover, a cylindrical portion 32b extending axially along the output shaft 34 is integrally provided on the outer periphery of the gear body 32a.

[0107] On the radially outer side of the cylindrical portion 32b, a plurality of helical teeth (second teeth) 32c are integrally provided in a manner arranged along the circumference of the cylindrical portion 32b. These helical teeth 32c are inclined at a predetermined angle relative to the axial direction of the pinion 31, thereby causing the helical gear 32 to rotate along with the rotation of the helical teeth 31b. Here, the number of helical teeth 32c provided on the helical gear 32 is set to "40". That is, in this embodiment, the reduction ratio of the reduction mechanism 30, which includes the pinion 31 and the helical gear 32, is "40". Furthermore, the meshing operation of the pinion 31 and the helical gear 32 will be described in detail below.

[0108] like Figure 5 and Figure 6 As shown, a meshing recess 32d is provided between adjacent helical teeth 32c. Therefore, the meshing recess 32d, like the helical teeth 32c, is inclined at a predetermined angle relative to the axial direction of the pinion 31. In addition, the meshing protrusion 31c of the pinion 31 engages with the meshing recess 32d.

[0109] Here, the cross section of the meshing recess 32d, which runs orthogonal to the axial direction of the pinion 31, is circular (approximately arc-shaped), and its center of curvature C3 is located on the reference circle TC of the helical gear 32. Furthermore, the diameter SR of the meshing recess 32d is slightly larger than the diameter D2 of the helical tooth 31b (SR > D2).

[0110] The reference circle of the helical tooth 31b (i.e., the first rotation trajectory OC) is circumscribed by the reference circle TC of the helical gear 32. Therefore, originally, at the center of the helical tooth 32c along the circumferential direction of the helical gear 32, the diameter of the helical gear 32 would be R (twice the distance between the rotation center C4 of the helical gear 32 and the first rotation trajectory OC). However, in this embodiment, the cross-sectional shape of the helical tooth 31b is circular, mimicking the shape of the meshing protrusion 31c. Therefore, although the pinion 31 is easy to manufacture, a thick-walled portion T of a predetermined thickness exists on the side of the helical tooth 31b opposite to the vertex BP side.

[0111] Therefore, to prevent interference (contact) between the helical teeth 31b and the helical teeth 32c, the tooth height of the helical teeth 32c is reduced by an amount of retraction E, and set to a tooth height H that prevents the helical teeth 31b from contacting the helical teeth 32c. Here, the tooth height H of the helical teeth 32c is the height from the tooth root circle BC, which passes through the deepest part of the meshing recess 32d. Moreover, the number of teeth of the helical gear 32 is "40", and the number of meshing recesses 32d is also "40". Therefore, in this embodiment, the angle θ formed by adjacent meshing recesses 32d is "9 degrees".

[0112] To summarize the above, the shapes of pinion 31 and helical gear 32 are determined by satisfying the following various formulas respectively.

[0113] Specifically, the shape of the pinion 31 is determined based on the following formula (1).

[0114] (D2÷2+L)×2=D1···(1)

[0115] D2: Diameter of the spiral tooth 31b

[0116] L: Eccentricity

[0117] D1: Diameter of the second rotation trajectory PR

[0118] Moreover, the shape of the helical gear 32 is determined based on the following equations (2) to (4).

[0119] L×2×reduction ratio=R···(2)

[0120] L: Eccentricity

[0121] R: The diameter of the center of the helical tooth 32c

[0122] Reduction ratio: In this embodiment, it is "40".

[0123] That is, as shown in equation (2), the reduction ratio of the pinion 31 and the helical gear 32 (reduction mechanism 30) is equal to the ratio of the first distance to the second distance. The first distance is the distance between the curvature center C2 of the meshing protrusion 31c and the rotation center C1 of the pinion 31 (i.e., eccentricity L), and the second distance is the distance between the curvature center C3 of the meshing recess 32d and the rotation center C4 of the helical gear 32 (i.e., R / 2).

[0124] SR=D2+α···(3)

[0125] SR: Diameter of the 32d engagement recess

[0126] D2: Diameter of the spiral tooth 31b

[0127] α: minute quantity

[0128] D2÷2-L×2+β=E···(4)

[0129] D2: Diameter of the spiral tooth 31b

[0130] L: Eccentricity

[0131] β: minute amount

[0132] E: Tooth height reduction of helical tooth 32c

[0133] Here, the minute amounts α and β in equations (3) and (4) are set values ​​for smoothly meshing the engagement protrusion 31c and the engagement recess 32d, and are appropriately set to minute optimal values ​​according to the detailed shape of the tip of the helical tooth 32c (a minute curve or a conical shape, etc.).

[0134] Next, the operation of the reduction mechanism 30 formed as described above, namely the meshing operation of the pinion 31 and the helical gear 32, will be explained in detail using the accompanying drawings.

[0135] Figure 7 The state indicated by "0 degrees" is the same as Figure 5 The same state is shown. In this state, the apex BP of the meshing protrusion 31c of the pinion 31 becomes the meshing recess 32d of the helical gear 32. That is, the meshing protrusion 31c and the meshing recess 32d are meshed with each other.

[0136] Next, during the operation of the reduction mechanism 30, the engagement protrusion 31c and the engagement recess 32d are engaged with each other, that is... Figure 7 The state indicated by "0 degrees" ( Figure 5(As shown) the helical gear 31b gradually moves slowly along its axial direction. Therefore, since the meshing recess 32d is inclined relative to the axial direction of the pinion 31, the helical gear 32 rotates at a reduced speed compared to the pinion 31. Thus, the helical gear 32 rotates in tandem with the rotation of the pinion 31.

[0137] Here, we focus only on a portion of the helical teeth 31b along the axial direction (e.g., along...). Figure 4 (part of the AA line), if the pinion 31 is in Figure 7 When rotated counterclockwise from the "0 degrees" position, the apex BP of the meshing cam 31c also rotates counterclockwise. Thus, the meshing cam 31c rotates as follows: "75 degrees" → "133 degrees" → "190 degrees" → "227 degrees" → "266 degrees," passing one helical tooth 32c. Then, as... Figure 7 As shown in the “360-degree” state, the engaging protrusion 31c, having rotated one full circle, engages with the adjacent engaging recess 32d (refer to the movement state marked with white circles in the figure).

[0138] Thus, for every one revolution of the helical tooth 31b, the helical gear 32 rotates by the amount of one helical tooth 32c (one meshing recess 32d). That is, during the period when the pinion 31 rotates once, the helical gear 32 rotates only 9 degrees. In other words, if the pinion 31 rotates 40 times, the helical gear 32 will only rotate once (i.e., the reduction ratio is "40"). As a result, the helical gear 32 rotates with a rotational torque (high torque) 40 times that of the pinion 31.

[0139] As detailed above, according to Embodiment 1, a spiral meshing protrusion 31c is provided on the pinion 31, and a plurality of meshing recesses 32d are provided on the helical gear 32 for meshing of the meshing protrusion 31c. These meshing protrusions 31c and meshing recesses 32d are formed in an arc shape in a direction orthogonal to the axial direction of the pinion 31.

[0140] Therefore, the pinion 31 and helical gear 32 can be configured as an arc-shaped, uneven meshing structure that will not deteriorate the meshing state between them. Furthermore, the number of teeth of the pinion 31 can be set to one, and the number of teeth of the helical gear 32 can be increased ("40" in this embodiment) to easily increase the tooth difference. Therefore, the reduction ratio can be further increased without increasing the volume of the reduction mechanism 30.

[0141] Furthermore, according to Embodiment 1, the axis of the pinion 31 is parallel to the axis of the helical gear 32, thus making it more compact than a worm gear reducer that includes a worm and a worm wheel with intersecting axes.

[0142] Next, various embodiments of the present invention will be described in detail with reference to the accompanying drawings. Furthermore, parts having the same function as those in Embodiment 1 will be labeled with the same symbols, and their detailed descriptions will be omitted.

[0143] Figure 8 The diagram shows the representation of embodiment 2. Figure 5 The corresponding diagram, Figure 9 The diagram shows the representation of embodiment 3. Figure 5 The corresponding diagram, Figure 10 The diagram shows the representation of embodiment 4. Figure 5 The corresponding diagram, Figure 11 The diagram shows the representation of embodiment 5. Figure 5 The corresponding diagram, Figure 12 An explanatory diagram illustrating embodiment 6 (face gear). Figure 13 An explanatory diagram illustrating embodiment 7 (herringbone gear).

[0144] [Implementation Method 2]

[0145] like Figure 8 As shown, in the reduction mechanism 40 of Embodiment 2, the shape of the helical teeth (first tooth portion) 41 provided on the pinion 31 is different from the shape of the helical teeth (second tooth portion) 42 provided on the helical gear 32. Specifically, at the end (the lower surface in the figure) opposite to the vertex BP side relative to the curvature center C2 of the meshing protrusion 31c of the helical teeth, a clearance portion 43 is provided to prevent interference (contact) with the helical teeth 42. The clearance portion 43 is formed by a flat surface centered on the curvature center C2 of the meshing protrusion 31c on the side opposite to the vertex BP side.

[0146] Furthermore, the tip of the helical tooth 42 is extended into the interior of the arc-shaped space 44 (shaded area in the figure) formed by providing the clearance portion 43, thereby bringing the tip of the helical tooth 42 closer to the clearance portion 43. Specifically, the tooth height H1 of the helical tooth 42 becomes the tooth height H of the helical tooth 32c in Embodiment 1 (see reference). Figure 6 It is approximately 1.5 times the size of (H1 > H).

[0147] In Embodiment 2, as described above, the same effects as in Embodiment 1 can be achieved. Furthermore, in Embodiment 2, the spiral tooth 41 has a clearance portion 43, which allows the spiral tooth 41 to be smaller and lighter. Moreover, the tooth height H1 of the helical tooth 42 can be set to a sufficient height, improving the meshing strength between the meshing protrusion 31c and the meshing recess 32d, and enabling higher torque power transmission.

[0148] [Implementation Method 3]

[0149] like Figure 9As shown, in the reduction mechanism 50 of Embodiment 3, only the shape of the helical tooth (first tooth portion) 51 provided on the pinion 31 is different. Specifically, the helical tooth 51 is formed such that its cross-section along a direction orthogonal to the axial direction of the pinion 31 is approximately elliptical. Specifically, a predetermined amount is removed from both sides of the helical tooth 51, centered on the auxiliary line AL connecting the vertex BP of the meshing protrusion 31c to the rotation center C1 of the pinion 31. Specifically, portions of a pair of arc-shaped spaces 52 (shaded areas) on both sides of the helical tooth 51 centered on the auxiliary line AL are each removed. At this time, the removal is performed with the center of curvature of the arc-shaped portion of the meshing protrusion 31c having the vertex BP being the same as C2 in Embodiment 1.

[0150] In Embodiment 3, as described above, the same effects as in Embodiment 1 can be achieved. In addition, in Embodiment 3, compared with the helical teeth 31b of the reduction mechanism 30 in Embodiment 1, the volume of a portion of the pair of arc-shaped spaces 52 can be reduced, thereby achieving a smaller and lighter pinion 31.

[0151] [Implementation Method 4]

[0152] like Figure 10 As shown, in the reduction mechanism 60 of Embodiment 4, only the shape of the helical teeth (first tooth portion) 61 provided on the pinion 31 is different. Specifically, the helical teeth 61 are formed such that the cross section along the direction orthogonal to the axial direction of the pinion 31 is approximately fan-shaped (approximately triangular rice ball shape). Specifically, with the auxiliary line AL connecting the vertex BP of the meshing protrusion 31c to the rotation center C1 of the pinion 31 as the center, the portions on both sides of the helical teeth 61 near the vertex BP are removed by a predetermined amount. Specifically, the portions of the pair of arc-shaped spaces 62 (shaded areas) on both sides of the helical teeth 61 near the vertex BP, centered on the auxiliary line AL, are each removed. At this time, the removal is performed with the center of curvature of the arc-shaped portion of the meshing protrusion 31c having the vertex BP being the same as C2 in Embodiment 1.

[0153] In Embodiment 4, as described above, the same effects as in Embodiment 1 can be achieved. Furthermore, in Embodiment 4, compared to the helical teeth 31b of the reduction mechanism 30 in Embodiment 1, the volume of a portion of the pair of arc-shaped spaces 62 can be reduced, thus achieving a smaller and lighter pinion 31. Moreover, compared to the reduction mechanism 50 in Embodiment 3, less material is removed, thus preventing a decrease in the rigidity of the helical teeth 61.

[0154] Furthermore, instead of having a symmetrical shape on both sides of the auxiliary line AL as the center, as in Embodiments 3 and 4, the shape can be asymmetrical on both sides of the auxiliary line AL as the center. Moreover, the shape of the removed portion is not limited to the arc shape as in Embodiments 3 and 4, but can also be a polygonal shape or the like; its shape is not limited.

[0155] [Implementation Method 5]

[0156] like Figure 11 As shown, in the reduction mechanism 70 of Embodiment 5, the shape of the helical teeth (first tooth portion) 71 provided on the pinion 31 is different from the shape of the helical teeth (second tooth portion) 72 provided on the helical gear 32. Specifically, the helical teeth 71 are formed in the shape of a coil spring, and the rotation center C1 of the pinion 31 is not provided within the cross-section of the helical teeth 71 in a direction orthogonal to the axial direction of the pinion 31. Here, the diameter D3 of the helical teeth 71 is smaller than the diameter D2 of the helical teeth 31b in Embodiment 1 (D3 < D2).

[0157] Furthermore, the center of curvature C5 of the meshing protrusion 31c is positioned further away from the rotation center C1 of the pinion 31 compared to Embodiment 1. Specifically, the distance between the center of curvature C5 of the meshing protrusion 31c and the rotation center C1 of the pinion 31 is set to L1, and this eccentricity L1 is approximately twice the eccentricity L of Embodiment 1. Therefore, as the pinion 31 rotates, the center C5 of the helical tooth 71 (i.e., the center of curvature C5 of the meshing protrusion 31c) follows a path longer than the first rotational trajectory OC (refer to...). Figure 5 The first rotational trajectory OC1 has a larger diameter.

[0158] Furthermore, the center C5 of the helical tooth 71 follows the first rotational trajectory OC1 of the major diameter, thus the tooth height of the helical tooth 72 of the helical gear 32 is set low, as H2. Specifically, the tooth height H2 of the helical tooth 72 becomes the tooth height H of the helical tooth 32c in Embodiment 1 (refer to...). Figure 5 It is approximately 2 / 3 the size of (H2 < H).

[0159] In Embodiment 5, as described above, the same effects as in Embodiment 1 can be achieved. In addition, in Embodiment 5, the volume of the helical teeth 71 can be further reduced, thus making the helical teeth 71 smaller and lighter.

[0160] [Implementation Method 6]

[0161] like Figure 12 As shown, the deceleration mechanism 80 of Embodiment 6 differs only in the following aspects: instead of Figure 3The helical gear 32 shown above meshes with the pinion 31, forming a face gear 81. That is, in this embodiment, the face gear 81 constitutes the second gear of the present invention. Specifically, the axis of the face gear 81 and the axis of the pinion 31 are orthogonal to each other, forming a so-called intersecting axis gear mechanism.

[0162] The face gear 81 is formed in a ring shape, and its surface is like... Figure 12 As shown, the gear has a plurality of helical teeth (second teeth) 82 and a plurality of meshing recesses 83 between adjacent helical teeth 82. In addition, the plurality of helical teeth 82 and the plurality of meshing recesses 83 are inclined relative to the axial direction of the pinion 31 and are arranged along the circumferential direction of the face gear 81.

[0163] Although not shown in detail here, the meshing recess 83 is formed in an arc shape in a direction orthogonal to the axial direction of the pinion 31, and it is similar to the meshing recess 32d in Embodiment 1 (see Figure 1). Figure 5 Similarly, the terrain becomes arc-shaped. Thus, similarly to embodiment 1, the meshing protrusion 31c of the pinion 31 meshes with the meshing recess 83 of the face gear 81.

[0164] Furthermore, the high-speed rotation of the pinion 31 in the direction of arrow AR1 in the figure results in the low-speed rotation of the face gear 81 in the direction of arrow AR2 in the figure. In addition, the high-torque rotational force is output from the output part (not shown) provided on the face gear 81 to the driven object (not shown).

[0165] In the above-described embodiment 6, the same effects as in embodiment 1 can be achieved.

[0166] [Implementation Method 7]

[0167] like Figure 13 As shown, the reduction mechanism 90 of Embodiment 7 employs the following structure: a pair of reduction mechanisms 30, including a pinion 31 and a helical gear 32, are coupled in such a way that they are mirror-symmetrical about each other, with the coupling portion TP as the boundary. That is, the coupled pair of helical gears 32, in an integrated state, become a herringbone gear (second gear) 91. Furthermore, the mountain teeth (second tooth portions) 91a of the herringbone gear 91 are formed into a generally V-shaped appearance by helical teeth 32c facing each other in a mirror-symmetrical manner. Therefore, between adjacent mountain teeth 91a, there are meshing recesses 32d facing each other in a generally V-shaped appearance.

[0168] Furthermore, the pair of pinions 31 that mesh together form a double pinion (first gear) 92 in an integrated state. The double pinion 92 has a pair of helical teeth 31b facing each other in a mirror-symmetrical manner. That is, the helical directions of these helical teeth 31b are opposite. In addition, the meshing protrusions 31c of these helical teeth 31b respectively mesh with the meshing recesses 32d between adjacent pinions 91a.

[0169] In Embodiment 7, as described above, the same effects as in Embodiment 1 can be achieved. Furthermore, Embodiment 7 employs a structure in which a pair of reduction gears 30 are mirror-symmetrically coupled, i.e., a herringbone gear structure, thus... Figure 13 As shown by arrows F1 and F2, the thrust that is intended to move the herringbone gear 91 or the double pinion 92 along its axial direction can be counteracted (eliminated).

[0170] That is, even if the double pinion 92 is rotated in the direction of the solid arrow or the dashed arrow in the figure, the double pinion 92, or the herringbone gear 91 that rotates therefrom, will not move axially. Therefore, the structure of the housing side that houses the double pinion 92 and the herringbone gear 91 can be further simplified.

[0171] This invention is not limited to the described embodiments, and various modifications can be made without departing from its spirit. For example, in embodiments 3 and 4, it is shown that the area near the engaging protrusion 31c is removed in such a way that the center of curvature of the arcuate portion of the engaging protrusion 31c with the vertex BP is the same as C2 in embodiment 1, but the invention is not limited thereto. For example, it may also be done in accordance with embodiment 5 (see embodiment 5). Figure 11 Similarly, the vicinity of the meshing protrusion 31c is removed in such a way that the center of curvature of the arc-shaped portion of the meshing protrusion 31c with the vertex BP is significantly eccentric to the rotation center C1 of the pinion 31.

[0172] Furthermore, the embodiments described show that the deceleration mechanisms 30, 40, 50, 60, 70, 80, and 90 (motor 10 with deceleration mechanism) are suitable as drive sources for windshield wiper devices mounted on vehicles. However, the present invention is not limited to this and can also be applied to other drive sources such as electric window devices, sunroof devices, and seat lift devices.

[0173] Furthermore, in the various embodiments described, a motor 10 with a reduction mechanism is shown, which uses a brushless motor 20 to drive the reduction mechanisms 30, 40, 50, 60, 70, 80, and 90. However, the present invention is not limited to this. A brushed motor can also be used instead of the brushless motor 20 to drive the reduction mechanisms 30, 40, 50, 60, 70, 80, and 90.

[0174] In addition, the material, shape, size, number, and placement of the structural elements in each of the various embodiments are arbitrary as long as they achieve the present invention, and are not limited to the various embodiments.

[0175] Hereinafter, Embodiment 8 of the present invention will be described in detail with reference to the accompanying drawings.

[0176] Figure 14 This is a perspective view of a motor with a speed reduction mechanism, viewed from the side of the connector connection. Figure 15 This is a perspective view of a motor with a reduction gear mechanism, viewed from the output shaft side. Figure 16 A perspective view illustrating the internal structure of a motor with a speed reduction mechanism. Figure 17 This is a magnified three-dimensional diagram showing the meshing part of the pinion and helical gear. Figure 18 Indicates along Figure 17 A cross-sectional view of line A1-A1. Figure 19 An explanatory diagram illustrating the changes in inter-core pitch offset, pressure angle, and backlash in Embodiment 8. Figure 20 An explanatory diagram illustrating the changes in inter-core pitch offset, pressure angle, and backlash in the comparative example. Figure 21 A graph showing a comparison of the changes in tooth clearance between Embodiment 8 and the comparative example. Figure 22 A graph showing a comparison of the changes in pressure angle between Embodiment 8 and the comparative example.

[0177] Figure 14 and Figure 15 The motor 110 with a reduction gear shown is, for example, a drive source for a windshield wiper unit (not shown) mounted on a vehicle such as an automobile. More specifically, the motor 110 with a reduction gear is disposed on the front side of the windshield (not shown) and causes the windshield wiper member (not shown) which is oscillating freely on the windshield to oscillate within a predetermined wiping range (between the downward reversing position and the upward reversing position).

[0178] The motor 110 with a reduction gear includes a housing 111 forming its outer contour. Additionally, as... Figure 16As shown, a brushless motor 120 and a reduction gear 130 are rotatably housed inside the housing 111. Here, the housing 111 is formed of an aluminum shell 112 and a plastic cover member 113.

[0179] like Figure 14 and Figure 15 As shown, the shell 112 is formed into a generally bowl-shaped form by injection molding molten aluminum material. Specifically, the shell 112 includes a bottom wall portion 112a, a side wall portion 112b integrally formed therearound, and a shell flange 112c provided on the opening side (left side in the figure) of the shell 112.

[0180] At approximately the center of the bottom wall portion 112a, a cylindrical support portion 112d is integrally provided to rotatably hold the output shaft 134. On the radially inner side of the support portion 112d, a cylindrical bearing member (not shown), referred to as a sliding bearing, is installed, thereby allowing the output shaft 134 to rotate smoothly relative to the support portion 112d without wobbling.

[0181] Furthermore, a plurality of reinforcing ribs 112e are integrally provided on the radially outer side of the support portion 112d, extending radially from the support portion 112d as the center. These reinforcing ribs 112e are disposed between the support portion 112d and the bottom wall portion 112a, and are generally triangular in shape. These reinforcing ribs 112e improve the fixing strength of the support portion 112d to the bottom wall portion 112a and prevent undesirable conditions such as tilting of the support portion 112d relative to the bottom wall portion 112a.

[0182] Furthermore, a bearing component receiving portion 112f is integrally provided at a position eccentric to the support portion 112d on the bottom wall portion 112a. The bearing component receiving portion 112f is formed as a bottomed cylindrical shape and protrudes in the same direction as the protruding direction of the support portion 112d. Additionally, as... Figure 16 As shown, inside the bearing component housing 112f, a ball bearing 133 is housed that rotatably supports the front end of the pinion 131.

[0183] In addition, such as Figure 15 As shown, a retaining ring 112g is provided between the support portion 112d and the output shaft 134, thereby preventing the output shaft 134 from axially wobbling in the support portion 112d. This ensures the quiet operation of the motor 110 with the reduction gear mechanism.

[0184] The cover member 113 forming the housing 111 is formed into a generally flat plate shape by injection molding molten plastic material. Specifically, the cover member 113 includes a body portion 113a and a cover flange 113b integrally disposed around it. In addition, the cover flange 113b abuts against the shell flange 112c via a sealing member such as an O-ring (not shown). This prevents rainwater and the like from entering the housing 111.

[0185] Furthermore, a brushless motor 120 is integrally housed in the main body 113a of the cover member 113 (see reference). Figure 16 The motor housing 113c is formed as a bottomed cylindrical section and protrudes to the side opposite to the housing 112. With the cover member 113 installed on the housing 112, the motor housing 113c faces the bearing member housing 112f of the housing 112. Furthermore, the stator 121 of the brushless motor 120 (see reference 113c) is fixed inside the motor housing 113c. Figure 16 ).

[0186] Furthermore, a connector connection portion 113d is integrally provided on the body portion 113a of the cover member 113 for connection to an external connector (not shown) on the vehicle side. Inside the connector connection portion 113d, multiple terminal members 113e (for supplying drive current to the brushless motor 120) are provided. Figure 14 Only one end of the brushless motor 120 is shown in the diagram. Additionally, drive current is supplied to the brushless motor 120 from an external connector via these terminal members 113e.

[0187] Furthermore, a control board (not shown) is provided between the other end of the plurality of terminal members 113e and the brushless motor 120 to control the rotation state (speed or direction of rotation, etc.) of the brushless motor 120. As a result, the wiper member fixed to the front end of the output shaft 134 swings within a predetermined wiping range on the windshield. Additionally, the control board is fixed to the inside of the body portion 113a of the cover member 113.

[0188] like Figure 16 As shown, the brushless motor 120 housed inside the housing 111 includes an annular stator 121. The stator 121 is fixed to the motor housing portion 113c of the cover member 113 in an anti-rotation state (see reference). Figure 14 (the interior of)

[0189] The stator 121 is formed by stacking multiple thin steel plates (magnetic bodies), and has multiple teeth (not shown) on its radially inner side. Furthermore, multiple turns of U-phase, V-phase, and W-phase coils 121a are wound around these teeth using methods such as concentrated winding. Thus, by alternately supplying drive current to each coil 121a at predetermined times, the rotor 122, located radially inner side of the stator 121, is rotated in a predetermined direction with a predetermined drive torque.

[0190] A rotor 122 is provided radially inside the stator 121, rotating freely through a small gap (air gap). The rotor 122 includes a rotor body 122a formed by stacking multiple thin steel plates (magnetic bodies) into a generally cylindrical shape, and a cylindrical permanent magnet 122b is provided on its outer periphery. Here, the permanent magnet 122b is magnetized by alternating N poles, S poles, etc., along its circumferential direction. In addition, the permanent magnet 122b is firmly fixed to the rotor body 122a in a rotatable manner by means of adhesives or the like.

[0191] Thus, the brushless motor 120 of this embodiment becomes a brushless motor with a surface permanent magnet (SPM) structure, in which permanent magnets 122b are fixed on the surface of the rotor body 122a. However, it is not limited to a brushless motor with an SPM structure; a brushless motor with an interior permanent magnet (IPM) structure, in which multiple permanent magnets are embedded in the rotor body 122a, can also be used.

[0192] Furthermore, instead of a single cylindrical permanent magnet 122b, multiple permanent magnets with cross-sections formed in a generally arc shape along the direction intersecting the axis of the rotor body 122a can be arranged at equal intervals along the circumference of the rotor body 122a in an alternating manner with alternating magnetic poles. Moreover, the number of poles of the permanent magnet 122b can be arbitrarily set to two poles or more, depending on the specifications of the brushless motor 120.

[0193] like Figure 16 As shown, the reduction mechanism 130 housed inside the housing 111 includes a pinion (first gear) 131 formed in a generally rod shape and a helical gear (second gear) 132 formed in a generally disc shape.

[0194] Here, the axes of the pinion 131 and the helical gear 132 are parallel to each other. As a result, the reduction mechanism 130 can be made more compact than a worm gear reducer that includes a worm and a worm wheel with intersecting axes.

[0195] Furthermore, the pinion 131 is disposed on the input side (drive source side) of the motor 110 with the reduction mechanism, and the helical gear 132 is disposed on the output side (drive object side) of the motor 110 with the reduction mechanism. That is, the reduction mechanism 130 reduces the high-speed rotation of the pinion 131 with fewer teeth to the low-speed rotation of the helical gear 132 with more teeth.

[0196] Here, the base end of the pinion 131 is firmly fixed to the rotation center of the rotor body 122a by pressing or the like, and the pinion 131 rotates integrally with the rotor body 122a. That is, the pinion 131 also functions as the drive shaft of the motor 110 with a reduction mechanism, driving the pinion 131 to rotate. In other words, the pinion 131 constitutes the rotation shaft of the present invention.

[0197] Furthermore, the front end of the pinion 131 is rotatably supported by the ball bearing 133. Moreover, at the rotation center of the helical gear 132, the base end of the output shaft 134 is firmly fixed by pressing or the like, and the output shaft 134 rotates integrally with the helical gear 132.

[0198] The pinion 131 forming the reduction mechanism 130 is made of metal and is in the shape of... Figures 16 to 19 The shape is as shown. Specifically, the pinion 131 has a pinion body 131a formed in a generally cylindrical shape, whose axial base end side is fixed to the rotor body 122a, and whose axial front end side is rotatably supported on the ball bearing 133. That is, the rotation center C11 of the pinion 131 (pinion body 131a) coincides with the rotation center of the rotor body 122a and the ball bearing 133.

[0199] On the axial portion of the pinion body 131a facing the helical gear 132, a helical tooth 131b is integrally provided. Specifically, the axial length of the helical tooth 131b is set to be slightly longer than the axial length of the helical gear 132. Thus, the helical tooth 131b can reliably mesh with the helical gear 132.

[0200] In addition, the helical tooth 131b extends continuously in a helical shape along the axial direction of the pinion 131, and there is only one helical tooth 131b on the pinion 131. That is, the number of teeth of the pinion 131 is set to "1".

[0201] like Figure 18 As shown, the helical tooth 131b is formed with a circular cross-section along a direction orthogonal to the axial direction of the pinion 131, and its diameter is φ1. Specifically, in this embodiment, φ1 is set to 5.45 mm.

[0202] Furthermore, the center C21 of the helical tooth 131b is eccentric (offset) relative to the rotation center C11 of the pinion 131 by a predetermined distance L11. Thus, as the pinion 131 rotates, the center C21 of the helical tooth 131b follows the trajectory OC1. In other words, the trajectory OC1 forms the reference circle of the helical tooth 131b.

[0203] Moreover, such as Figure 18 As shown, if an auxiliary line AL1 is drawn from the rotation center C11 of the pinion 131 to the center C21 (downward in the figure) of the helical tooth 131b, and the auxiliary line AL1 is further extended to the surface of the helical tooth 131b, then the auxiliary line AL1 intersects the surface of the helical tooth 131b. The intersection point becomes the vertex BP1 of the meshing protrusion 131c.

[0204] Here, the meshing protrusion 131c is a meshing portion that forms part of the helical tooth 131b, and the meshing protrusion 131c also extends helically along the axial direction of the pinion 131. In addition, the meshing protrusion 131c meshes with the meshing recess 132d between adjacent helical teeth 132c of the helical gear 132.

[0205] The meshing protrusion 131c forms part of the helical tooth 131b, and is formed in an arc shape along the rotation direction of the pinion 131. Thus, the radius of curvature R11 of the meshing protrusion 131c is φ1 / 2 (≈2.72mm).

[0206] Thus, the engagement protrusion 131c is provided on the portion of the helical tooth 131b near the apex BP1, and its center of curvature coincides with the center C21 of the helical tooth 131b. Here, the radius of curvature R11 of the engagement protrusion 131c constitutes the first radius of curvature of the present invention.

[0207] Additionally, as the pinion 131 rotates, the apex BP1 of the meshing protrusion 131c... Figure 18 The line following the surface forming the pinion body 131a is shown. Thus, the meshing protrusions 131c along the axial direction of the pinion 131 continuously mesh with the meshing recesses 132d, thereby causing the helical gear 132 to rotate in a decelerated state.

[0208] also, Figure 18 The image shows the state in which the meshing protrusion 131c and the meshing recess 132d are engaged with each other.

[0209] The helical gear 132 forming the reduction mechanism 130 is made of plastic and is in the shape of... Figures 16 to 19The shape is as shown. Specifically, the helical gear 132 includes a gear body 132a formed in a generally disc shape, and the base end side of the output shaft 134 is firmly fixed to the central portion of the gear body 132a by pressing or the like. Moreover, a cylindrical portion 132b extending axially along the output shaft 134 is integrally provided on the outer periphery of the gear body 132a.

[0210] On the radially outer side of the cylindrical portion 132b, a plurality of helical teeth 132c are integrally provided in a manner arranged along the circumferential direction of the cylindrical portion 132b. These helical teeth 132c are inclined at a predetermined angle relative to the axial direction of the pinion 131, thereby causing the helical gear 132 to rotate as the helical teeth 131b rotate.

[0211] Here, the number of helical teeth 132c provided on the helical gear 132 is set to "40". That is, in this embodiment, the reduction ratio of the reduction mechanism 130, which includes the pinion 131 and the helical gear 132, is "40".

[0212] like Figure 18 As shown, a meshing recess 132d is provided between adjacent helical teeth 132c. Therefore, the meshing recess 132d, like the helical teeth 132c, is inclined at a predetermined angle relative to the axial direction of the pinion 131. In addition, the meshing protrusion 131c of the pinion 131 meshes with the meshing recess 132d.

[0213] The meshing recess 132d is formed in a generally arc shape along the rotation direction of the helical gear 132. Furthermore, an arc-shaped bottom (bottom) 132e is provided at the center of the meshing recess 132d along the rotation direction of the helical gear 132. The arc-shaped bottom 132e forms the deepest part of the meshing recess 132d. In the meshing state of the meshing protrusion 131c and the meshing recess 132d, a predetermined gap S1 is formed between the apex BP1 of the meshing protrusion 131c and the arc-shaped bottom 132e of the meshing recess 132d.

[0214] The gap S1 contains lubricating oil G1 (shaded area in the figure) to ensure smooth operation of the reduction mechanism 130. That is, the gap S1 functions as a lubricating oil retainer for holding the lubricating oil G1. Furthermore, the lubricating oil G1... Figure 19 Illustrations are omitted in the text; only illustrations are shown in the text. Figure 18 The diagram in the middle is shown.

[0215] Here, the radius of curvature R21 of the arc-shaped bottom 132e is set to a smaller value than the radius of curvature R11 of the engaging protrusion 131c (R21 < R11). Specifically, in this embodiment, the radius of curvature R21 is set to 2.5 mm. Therefore, even if the apex BP1 of the engaging protrusion 131c reaches its lowest point in the arc-shaped bottom 132e of the engaging recess 132d, the lubricating oil G1 held in the gap S1 will not be squeezed out and depleted. Thus, the smooth operation of the reduction mechanism 130 is maintained for a long time.

[0216] Furthermore, the engagement recess 132d includes a pair of arc-shaped sidewall portions (sidewall portions) 132f. These arc-shaped sidewall portions 132f are provided on both sides of the arc-shaped bottom 132e along the rotation direction of the helical gear 132, and smoothly connected to both sides of the arc-shaped bottom 132e. That is, no step or other difference is formed between the arc-shaped bottom 132e and the pair of arc-shaped sidewall portions 132f. Therefore, even if the engagement point EP1 of the engagement protrusion 131c and the engagement recess 132d falls between the arc-shaped bottom 132e and the arc-shaped sidewall portions 132f, it will not hinder the smooth operation of the reduction mechanism 130.

[0217] Here, as Figure 19 As shown in the upper section, the distance between the two arc-shaped sidewall portions 132f, that is, the groove width of the meshing recess 132d, is set to L21. This distance L21 is set to a size slightly smaller than the diameter φ1 of the helical tooth 131b (L21 < φ1).

[0218] Furthermore, a pair of arc-shaped sidewall portions 132f are formed with a predetermined radius of curvature, recessed radially outward from the engagement recess 132d. That is, these arc-shaped sidewall portions 132f become arc-shaped recesses. Additionally, the radius of curvature R31 of the arc-shaped sidewall portions 132f (refer to...) Figure 18 The radius of curvature R31 is set to be twice the size of the radius of curvature R11 of the engaging protrusion 131c (R31 = 2 × R11). Specifically, in this embodiment, the radius of curvature R31 is set to 5.45 mm. Here, the radius of curvature R31 of the arc-shaped sidewall portion 132f constitutes the second radius of curvature of the present invention.

[0219] Furthermore, in this embodiment, an arc-shaped sidewall portion 132f is formed with a radius of curvature R31, recessed radially outward from the engagement recess 132d, thus different from the reverse arc-shaped sidewall portion 151 of Embodiment 10 described later (see...). Figure 24 Compared to the previous method, it has the advantage that the engaging protrusion 131c is less likely to disengage from the engaging recess 132d.

[0220] If we summarize the radii of curvature R11 to R31, the radius of curvature R11 of the meshing protrusion 131c is 2.72 (=5.45÷2) mm, the radius of curvature R21 of the arc-shaped bottom 132e is 2.5 mm, and the radius of curvature R31 of the arc-shaped sidewall 132f is 5.45 mm (R31>R11>R21).

[0221] Furthermore, in this embodiment, by adopting the aforementioned dimensional relationship, the meshing condition of the pinion 131 and the helical gear 132 is set as follows: that is, in the state where the meshing protrusion 131c is deeply engaged with the meshing recess 132d ( Figure 18 In the state shown, a gap S1 for holding lubricating oil G1 is formed between the apex BP1 of the meshing protrusion 131c and the arc-shaped bottom 132e of the meshing recess 132d, and the meshing point EP1 of the meshing protrusion 131c and the meshing recess 132d is disposed on the arc-shaped sidewall portion 132f.

[0222] Here, Figure 18 and Figure 19 In order to clearly distinguish the junction between the arc-shaped bottom 132e and the pair of arc-shaped sidewalls 132f, a junction line BD1 (a dotted line) is drawn at the junction.

[0223] Next, using the accompanying drawings, we will discuss the rotation center C11 of the pinion 131 and the rotation center C31 of the helical gear 132 in the reduction mechanism 130 formed as described above (see reference). Figure 16 The changes in backlash β1 and pressure angle α1, which are accompanied by displacement of the meshing point EP1, are explained in detail when there is a deviation in the distance (inter-core pitch) between the two parts.

[0224] Here, Figure 20 In a comparative example that is substantially the same as the prior art, the pinion 131 is the same pinion as that of the present invention, and the helical gear 1100 is a helical gear including a meshing recess 1101 formed into an arc shape with a certain radius of curvature R1. Furthermore, the radius of curvature R11 of the meshing protrusion 131c and the radius of curvature R1 of the meshing recess 1101 are substantially the same (R11≈R1).

[0225] [Case where intercore pitch is ±0]

[0226] When the offset of the inter-core pitch is 0 mm, such as Figure 19 As shown in the middle section, the meshing point EP1 of the present invention is located in the center of the more arc-shaped sidewall portion 132f and slightly closer to the tip of the helical tooth 132c. In contrast, as... Figure 20 As shown in the middle section, the meshing point EP1 of the comparative example is also located near the tip of the helical tooth 1102.

[0227] like Figure 21 As shown, the tooth gap β1 in this invention (solid line) is a smaller value than that in the center line, while in the comparative example (dashed line) it is a larger value (larger than that in the center line) than in this invention. Furthermore, as... Figure 22 As shown, the pressure angle α1 is shown as the value of the center line in the present invention (solid line), and a smaller value than that in the comparative example (dashed line).

[0228] [Case where the intercore pitch is -0.1mm]

[0229] When the offset of the intercore pitch is 0.1 mm on the negative side, such as Figure 19 As shown in the lower section, the engagement point EP1 of the present invention is disposed approximately in the central portion of the arc-shaped sidewall portion 132f. In contrast, as... Figure 20 As shown in the lower section, the engagement point EP1 of the comparative example is significantly displaced and positioned near the deepest part of the engagement recess 1101.

[0230] like Figure 21 As shown, the tooth gap β1 in this case is a smaller value in the present invention (solid line), and a larger value in the comparative example (dashed line). Furthermore, as... Figure 22 As shown, the pressure angle α1 in the present invention (solid line) is displayed as the value of the center line in the same way as in the case where the intercore pitch is ±0, while in the comparative example (dashed line) it is displayed as a value that is significantly larger than that in the present invention (approximately twice the size).

[0231] [Case where intercore pitch is +0.1mm]

[0232] When the offset of the inter-core pitch is 0.1 mm on the positive side, such as Figure 19 As shown in the upper section, compared to the case where the inter-core pitch offset is 0 mm, the meshing point EP1 of the present invention is positioned closer to the tip of the helical tooth 132c. In contrast, as... Figure 20 As shown in the upper section, the meshing point EP1 of the comparative example is located at the tip of the helical tooth 1102.

[0233] like Figure 21 As shown, the tooth gap β1 at this time shows a larger value than the center line in the present invention (solid line), and a further larger value than the present invention in the comparative example (dashed line). Moreover, as Figure 22 As shown, the pressure angle α1 in the present invention (solid line) is displayed as the value of the centerline in the same way as in the case where the intercore pitch is ±0, while in the comparative example (dashed line) a smaller value than that in the present invention is displayed.

[0234] Thus, when there is a deviation in the inter-core pitch between the pinion 131 and the helical gear 132, it is known that the gear reduction mechanism 130 of the present invention, compared with the gear reduction mechanism of a comparative example that is substantially the same as the prior art, has a smaller tooth backlash β1 (see reference). Figure 21 ).

[0235] Furthermore, regarding the pressure angle α1, it is known that in the deceleration mechanism of the comparative example, the pressure angle α1 deviates significantly between a value smaller than the centerline and a value larger than the centerline, but in the deceleration mechanism 130 of the present invention, the pressure angle α1 is stable at the value of the centerline (without deviation) (see reference). Figure 22 ).

[0236] As detailed above, in embodiment 8, a meshing protrusion 131c with a radius of curvature R11 is provided on the pinion 131, and a meshing recess 132d for meshing of the meshing protrusion 131c is provided on the helical gear 132. The meshing recess 132d includes: an arc-shaped bottom 132e located at the center of the meshing recess 132d along the rotation direction of the helical gear 132; and a pair of arc-shaped sidewall portions 132f located on both sides of the arc-shaped bottom 132e along the rotation direction of the helical gear 132. The arc-shaped sidewall portions 132f are arc-shaped recesses with a radius of curvature R31 larger than the radius of curvature R11.

[0237] Therefore, it is possible to achieve a small and lightweight motor 110 with a reduction mechanism 130, and even if there is a deviation in the core pitch between the pinion 131 and the helical gear 132, the deviation of the pressure angle α1 can be suppressed, and the tooth backlash β1 can be varied on the smaller side.

[0238] Furthermore, in embodiment 8, when the engagement protrusion 131c and engagement recess 132d are engaged, a gap S1 for holding lubricating oil G1 is provided between the engagement protrusion 131c and the arc-shaped bottom 132e, so that the smooth operation of the reduction mechanism 130 (motor 110 with reduction mechanism) can be maintained for a long time.

[0239] Next, several other embodiments of the present invention will be described in detail with reference to the accompanying drawings. Furthermore, parts having the same function as described in Embodiment 8 will be labeled with the same reference numerals, and their detailed descriptions will be omitted.

[0240] Figure 23 The diagram shows the representation of embodiment 9. Figure 18 The corresponding diagram, Figure 24 The diagram shows the representation of embodiment 10. Figure 18 The corresponding diagram, Figure 25 The diagram shows the representation of embodiment 11. Figure 18 The corresponding diagram, Figure 26 The diagram shows the relationship between the tooth diameter ratio and the backlash deviation in Embodiments 8, 10, and 11. Figure 27 A graph showing the relationship between the tooth diameter ratio and the deviation of the pressure angle for Embodiments 8, 10, and the involute gear is presented. Figure 28 A graph is shown to show the changes in the offset of the core pitch and the pressure angle of Embodiments 8, 10, and 11 and the involute gear.

[0241] [Implementation Method 9]

[0242] like Figure 23 As shown, the reduction mechanism 140 of Embodiment 9 differs from that of Embodiment 8 only in the shape of the meshing recess 132d of the helical gear 132. (See also: Reduction mechanism 130 of Embodiment 8) Figure 18 In embodiment 9, when the engagement protrusion 131c and engagement recess 132d are engaged, a gap S1 for retaining lubricating oil G1 is formed between the engagement protrusion 131c and the arc-shaped bottom 132e. In contrast, embodiment 9 provides an accumulation portion 141, which narrows (partially fills) the gap S1 formed between the engagement protrusion 131c and the arc-shaped bottom 132e when the engagement protrusion 131c and engagement recess 132d are engaged.

[0243] Specifically, such as Figure 23 As shown, the accumulation portion 141 narrows the gap S1 by the amount of thickness TD1 from the deepest part of the arc-shaped bottom 132e, and its surface becomes a flat surface SF1. However, the thickness TD1 of the accumulation portion 141 is set in such a way that the engaging protrusion 131c does not contact the flat surface SF1 of the accumulation portion 141 during the operation of the reduction mechanism 140. Thus, lubricating oil (not shown) can be retained in the tiny gap S1 between the engaging protrusion 131c and the flat surface SF1.

[0244] In Embodiment 9, as described above, the same effects as in Embodiment 8 can be achieved. In addition, Embodiment 9 can improve the strength of the tooth root of the helical tooth 132c, thereby suppressing the deformation of the helical tooth 132c and achieving higher torque transmission.

[0245] [Implementation Method 10]

[0246] like Figure 24 As shown, the reduction mechanism 150 of Embodiment 10 differs from that of Embodiment 8 only in the shape of the meshing recess 132d of the helical gear 132. The reduction mechanism 130 of Embodiment 8 (see...) Figure 18 In embodiment 8, an arc-shaped sidewall portion 132f with a radius of curvature R31 is provided, recessed radially outward from the meshing recess 132d. That is, in embodiment 8, the arc-shaped sidewall portion 132f becomes an arc-shaped recess. In contrast, in embodiment 10, a pair of reverse arc-shaped sidewall portions (sidewall portions) 151 are provided on both sides of the arc-shaped bottom 132e along the rotation direction of the helical gear 132.

[0247] Specifically, the reverse arcuate sidewall portion 151 is formed with a radius of curvature R41, protruding radially inward toward the engagement recess 132d. That is, these reverse arcuate sidewall portions 151 become arcuate protrusions. Furthermore, lubricating oil (not shown) is provided between the engagement protrusion 131c and the arcuate bottom 132e, similar to embodiment 8.

[0248] Here, the radius of curvature R41 of the reverse arc-shaped sidewall portion 151 is set to be twice the radius of curvature R11 of the engaging protrusion 131c (R41 = 2 × R11). That is, it is equal to the radius of curvature R31 of the arc-shaped sidewall portion 132f in Embodiment 8 (R41 = R31). The radius of curvature R41 of the reverse arc-shaped sidewall portion 151 constitutes the second radius of curvature of the present invention.

[0249] In the above-described embodiment 10, the same effects as in embodiment 8 can be achieved. Here, in embodiment 10, the effects can also be as described... Figure 23 The stacked portion is provided as shown in embodiment 9, which narrows the gap S1 formed between the engagement protrusion 131c and the arc-shaped bottom 132e when the engagement protrusion 131c and the engagement recess 132d are engaged.

[0250] [Implementation Method 11]

[0251] like Figure 25 As shown, the reduction mechanism 160 of Embodiment 11 differs from that of Embodiment 8 only in the shape of the meshing recess 132d of the helical gear 132. The reduction mechanism 130 of Embodiment 8 (see...) Figure 18 In embodiment 132, an arcuate sidewall portion 132f with a radius of curvature R31 is provided, recessed radially outward from the engagement recess 132d. In contrast, in embodiment 11, a pair of planar sidewall portions (sidewall portions) 161 are provided on both sides of the arcuate bottom 132e along the rotation direction of the helical gear 132, each including a plane extending straight from the arcuate bottom 132e.

[0252] Specifically, regarding the inclination angle of the pair of planar sidewall portions 161, they are inclined at an angle of 30° in a mirror-symmetrical manner, with the line segment LN1 passing through the center of the tip of the helical tooth 132c as the center. In addition, lubricating oil (not shown) is provided between the meshing protrusion 131c and the arc-shaped bottom 132e, similar to that in Embodiment 8.

[0253] In the above-described embodiment 11, the same effects as in embodiment 8 can be achieved. Here, in embodiment 11, the effects can also be as described... Figure 23The stacked portion is provided as shown in embodiment 9, which narrows the gap S1 formed between the engagement protrusion 131c and the arc-shaped bottom 132e when the engagement protrusion 131c and the engagement recess 132d are engaged.

[0254] Here, use Figures 26 to 28 Regarding the deceleration mechanism 130 of embodiment 8 (refer to...) Figure 18 ), the deceleration mechanism 150 of embodiment 10 (refer to Figure 24 ) and the deceleration mechanism 160 of embodiment 11 (see Figure 25 Each of their various characteristics is compared and explained at the same time.

[0255] Figure 26 This is a graph showing the relationship between the tooth diameter ratio and the backlash deviation [mm]. The tooth diameter ratio mentioned here refers to the ratio of the radius of curvature R11 of the meshing protrusion 131c to the radius of curvature R31 of the arc-shaped sidewall portion 132f. Therefore, in Embodiments 8 and 10, the tooth diameter ratio is "2" (2 times).

[0256] like Figure 26 As shown, in “Implementation Method 11” indicated by a dashed line, the engagement point EP1 (refer to…) Figure 25 The portion shown as a solid line becomes linear, independent of the tooth diameter ratio, and the backlash deviation is displayed at a constant value approximately at the centerline. In "Embodiment 8," as shown by the solid line, it was found that if the tooth diameter ratio is "2" or less, the backlash deviation increases. In contrast, in "Embodiment 10," as shown by the dashed line, it was found that the backlash deviation is stable near the value approximately at the centerline, regardless of the tooth diameter ratio. That is, it was found that "Embodiment 10" achieves a better effect in suppressing backlash deviation compared to "Embodiment 8."

[0257] From the perspective of "tooth gap" mentioned above, it is known that the ideal tooth diameter ratio, even if small, is approximately "2". That is, ideally, the radius of curvature R31 of the arc-shaped sidewall portion 132f and the radius of curvature R41 of the reverse arc-shaped sidewall portion 151 are both set to be at least twice the radius of curvature R11 of the meshing protrusion 131c.

[0258] Figure 27 A graph showing the relationship between the tooth diameter ratio and the deviation of the pressure angle [°], and in "Implementation 11", the meshing point EP1 (refer to...) Figure 25 The portion of the curve is straight, therefore the pressure angle does not deviate. Therefore, Figure 27 The diagram for "Implementation Method 11" is not included. On the other hand, for reference, the characteristics of existing involute gears are described.

[0259] As shown by the double-dotted line, involute gears, even if the pressure angle deviates, the deviation is within a very small angular range. In contrast, in "Embodiment 8" (shown by the solid line), it was found that if the tooth diameter ratio is "2" or less, the pressure angle deviation increases dramatically. Furthermore, in "Embodiment 8," the pressure angle deviation when the tooth diameter ratio is "2" is sufficiently acceptable for the product. On the other hand, in "Embodiment 10" (shown by the dashed line), it was found that when the tooth diameter ratio is "2," the pressure angle deviation is suppressed to approximately half that of "Embodiment 8." That is, it was found that "Embodiment 10" also achieves a better effect in suppressing the pressure angle deviation compared to "Embodiment 8."

[0260] From the above-mentioned "pressure angle" perspective, it is also known that the ideal tooth diameter ratio, even if small, is set to approximately "2". That is, ideally, the radius of curvature R31 of the arc-shaped sidewall portion 132f and the radius of curvature R41 of the reverse arc-shaped sidewall portion 151 are both set to be at least twice the size of the radius of curvature R11 of the meshing protrusion 131c.

[0261] Here, if we take Figure 20 The comparative examples shown are depicted in Figure 27 Then it becomes the part marked with an asterisk. That is, the tooth diameter ratio is approximately "1", and the deviation of the pressure angle is within... Figure 27 It becomes the maximum value within the recorded range.

[0262] Figure 28 A graph showing the relationship between the offset of the inter-core pitch [mm] and the pressure angle [°] reveals that "Embodiment 10" has the same characteristics as the existing involute gear (double-dotted line) shown in the reference diagram, while "Embodiment 8" has completely opposite characteristics. Furthermore, in "Embodiment 11," the meshing point EP1 (refer to...) Figure 25 The part is straight, so the pressure angle becomes a constant value.

[0263] Based on the relationship between the inter-core pitch offset and the pressure angle as described above, "Embodiment 8" and "Embodiment 10," which have completely opposite characteristics, can be appropriately selected and used according to the characteristics of the required reduction mechanism or the way the reduction mechanism is used. In other words, the variation of the reduction mechanism can be easily increased. Furthermore, "Embodiment 11," which shows approximately the middle characteristics of these embodiments, can also be added to the variation of the reduction mechanism.

[0264] This invention is not limited to the described embodiments, and various modifications can be made without departing from its spirit. The described embodiments show that the reduction mechanisms 130, 140, 150, and 160 (motor 110 with reduction mechanism) are suitable as drive sources for windshield wiper systems mounted on vehicles, but the invention is not limited thereto and can also be applied to other drive sources such as power window systems, sunroof systems, and seat lift systems.

[0265] Furthermore, in the various embodiments described, a motor 110 with a reduction mechanism is shown, in which a brushless motor 120 drives the reduction mechanisms 130, 140, 150, and 160. However, the present invention is not limited to this. A brushed motor can also be used instead of the brushless motor 120, and the brushed motor can be used to drive the reduction mechanisms 130, 140, 150, and 160.

[0266] Furthermore, the material, shape, size, number, and placement of each structural element in each of the embodiments described herein are arbitrary as long as they achieve the present invention, and are not limited to each of the embodiments described herein.

[0267] Hereinafter, embodiment 12 of the present invention will be described in detail with reference to the accompanying drawings.

[0268] Figure 29 This is a perspective view of a motor with a speed reduction mechanism, viewed from the side of the connector connection. Figure 30 This is a perspective view of a motor with a reduction gear mechanism, viewed from the output shaft side. Figure 31 An exploded perspective view illustrating the internal structure of a motor with a speed reduction mechanism. Figure 32 This is a cross-sectional view illustrating the internal structure of a motor with a speed reduction mechanism. Figure 33 of (a), Figure 33 (b) represents a three-dimensional view of the gearbox as a single unit. Figure 34 An explanatory diagram illustrating the manufacturing sequence of the gearbox. Figure 35 An enlarged cross-sectional view showing details of the sensor substrate. Figure 36 This shows an enlarged cross-sectional view of a brushless motor. Figure 37 Indicates along Figure 36 A cross-sectional view of line A2-A2. Figure 38 A perspective view showing details of the speed reduction mechanism.

[0269] Figure 29 and Figure 30The motor 210 with a reduction gear shown can be used, for example, as a drive source for a windshield wiper unit (not shown) mounted on a vehicle such as an automobile. More specifically, the motor 210 with a reduction gear is disposed on the front side of the windshield (not shown) and causes a windshield wiper component (not shown) that is freely mounted on the windshield to swing within a predetermined wiping range (between the downward reversing position and the upward reversing position).

[0270] The motor 210 with a reduction gear includes a housing 211 forming its outer contour. For example... Figure 31 and Figure 32 As shown, a brushless motor (motor unit) 220 and a reduction gear (reduction gear unit) 230 are rotatably housed inside the housing 211. Furthermore, a sensor substrate 240 for detecting the rotational state of the rotor 222 and the helical gear 232 is housed inside the housing 211. Here, the housing 211 includes a gearbox 212 made of die-cast aluminum and a cover member 213 made of plastic.

[0271] like Figures 29 to 33 As shown, the gearbox 212 is formed into a roughly bowl-shaped form by injection molding molten aluminum material. Specifically, the gearbox 212 includes a bottom wall portion 212a, a side wall portion 212b integrally formed around it, and an opening side provided on the gearbox 212. Figure 32 The shell flange 212c (upper middle side).

[0272] At approximately the center of the bottom wall portion 212a, a cylindrical support portion (support cylinder portion) 212d is integrally provided to rotatably support the output shaft 233. The axial length of the support portion 212d is set to be slightly larger than the height of the side wall portion 212b, and the portion of the support portion 212d near the axial center is fixed to the bottom wall portion 212a. As a result, a first cylinder portion 212d1 forming one side of the support portion 212d in the longitudinal direction protrudes from the bottom wall portion 212a toward the outside of the gearbox 212, and a second cylinder portion 212d2 forming the other side of the support portion 212d in the longitudinal direction protrudes from the bottom wall portion 212a toward the inside of the gearbox 212.

[0273] Therefore, by ensuring the axial length of the support portion 212d, the "jittering" of the output shaft 233 during the operation of the motor 210 with the reduction mechanism is effectively suppressed. Furthermore, by making the second cylindrical portion 212d2 of the support portion 212d protrude inwards towards the gearbox 212, the thickness T2 of the gearbox 212 (see reference) is suppressed. Figure 32 It becomes thicker.

[0274] like Figure 33As shown, to improve the fixing strength of the support column 212d to the bottom wall 212a, multiple first reinforcing ribs RB12 and second reinforcing ribs RB22 are provided on one and the other axial sides of the support column 212d. More specifically, the first reinforcing ribs RB12 are disposed on the outer periphery of the first cylindrical portion 212d1 side of the support column 212d, and the second reinforcing ribs RB22 are disposed on the outer periphery of the second cylindrical portion 212d2 side of the support column 212d. Moreover, eight first reinforcing ribs RB12 and eight second reinforcing ribs RB22 are provided at equal intervals (45° intervals) around the support column 212d.

[0275] Thus, a plurality of first reinforcing ribs RB12 are provided between the first cylindrical portion 212d1 of the support portion 212d and the bottom wall portion 212a, and are provided on the outside of the gearbox 212. Moreover, a plurality of second reinforcing ribs RB22 are provided between the second cylindrical portion 212d2 of the support portion 212d and the bottom wall portion 212a, and are provided inside the gearbox 212.

[0276] Multiple first reinforcing ribs RB12 and second reinforcing ribs RB22 are each formed into a roughly triangular shape and are integrally provided to support the support portion 212d and the bottom wall portion 212a. Thus, as... Figure 32 As shown, the support column 212d is fixed with sufficient strength to the relatively thin bottom wall portion 212a, thereby achieving the miniaturization and lightweight of the gearbox 212.

[0277] Here, the first reinforcing rib RB12 and the second reinforcing rib RB22 are respectively positioned at the same location relative to the circumferential direction of the support portion 212d (see reference). Figure 32 However, depending on the specifications of the gearbox 212, the first reinforcing rib RB12 and the second reinforcing rib RB22 may be arranged in different positions relative to the circumferential direction of the support portion 212d.

[0278] Furthermore, when the motor 210 with the reduction gear is running, and a digging-like reaction force is applied to the output shaft 233, the output shaft 233 will... Figure 32 Centered on the center of oscillation P2, the support portion 212d oscillates relative to it as shown by the dashed arrow SW2. At this time, a bottom wall portion 212a is provided near the center of oscillation P2, thus allowing the reaction force that would cause the support portion 212d to tilt to be distributed in a good balance to the first reinforcing rib RB12 and the second reinforcing rib RB22. Therefore, stress concentration at the connection between the support portion 212d and the bottom wall portion 212a, which could lead to cracking, etc., can be suppressed.

[0279] Here, gearbox 212 is via Figure 34The injection molding apparatus 250 shown is manufactured accordingly. Specifically, the injection molding apparatus 250 includes a lower mold 251 and an upper mold 252. The lower mold 251 is a fixed mold fixed to a base (not shown) of the injection molding apparatus 250 and forms the outer side of the gearbox 212. On the other hand, the upper mold 252 is a movable mold that is raised and lowered by a lifting mechanism (not shown) of the injection molding apparatus 250 and forms the inner side of the gearbox 212.

[0280] In addition, such as Figure 34 As shown, by operating the lifting mechanism, the upper mold 252 is connected to the lower mold 251, thereby forming a mold cavity CA2 inside the upper mold 251 and the lower mold 252. Furthermore, the upper mold 252 is provided with a distributor DS2 that supplies molten aluminum material (molten material) to the mold cavity CA2. Specifically, the distributor DS2 pressurizes the molten material into the supply passage 252a of the upper mold 252 at a predetermined pressure, thereby filling the mold cavity CA2 connected to the supply passage 252a with molten material.

[0281] At this point, as shown by arrows M12 and M22 in the figure, the molten material gradually and evenly fills the mold cavity CA2. Furthermore, particularly in the complex-shaped parts of the gearbox 212, namely the support column 212d and multiple first reinforcing ribs RB12 and second reinforcing ribs RB22 (see reference...), Figure 33 In the part shown by arrow M22 in the figure, the molten material branches in the vertical direction of the mold cavity CA2.

[0282] In this embodiment, compared to conventional ribs, the lengths of the first reinforcing rib RB12 and the second reinforcing rib RB22 along the axial direction of the support portion 212d are shortened. As a result, the molten material is efficiently and uniformly distributed throughout the portions forming the support portion 212d and the first and second reinforcing ribs RB12 and RB22. In other words, the gearbox 212 of this embodiment has a shape that allows for good molten flow. Therefore, the generation of defects such as casting voids or shortshots can be reliably suppressed, thereby improving the defect rate and increasing mass production capability.

[0283] Moreover, such as Figure 32 As shown, a cylindrical bearing member 212e, referred to as a "sliding bearing," is installed on the radially inner side of the support portion 212d. This allows the output shaft 233 to rotate smoothly relative to the support portion 212d without wobbling.

[0284] Furthermore, a bearing component receiving portion 212f is integrally provided at a position eccentric to the support portion 212d on the bottom wall portion 212a. The bearing component receiving portion 212f is formed into a bottomed cylindrical shape and protrudes from the bottom wall portion 212a toward the outside of the gearbox 212. In addition, a first ball bearing BR12 that rotatably supports the front end side of the pinion 231 is housed inside the bearing component receiving portion 212f.

[0285] Furthermore, a stop ring 212g is provided between the support portion 212d and the output shaft 233. This suppresses axial wobble of the output shaft 233 in the support portion 212d, ensuring the quietness of the motor 210 with the reduction mechanism.

[0286] The cover member 213 forming the housing 211 is formed by injection molding of molten plastic material, and includes a substrate holding portion 213a formed into a generally flat plate shape and a motor receiving portion 213b formed into a generally bottomed cylindrical shape. Furthermore, a cover flange 213c is integrally provided around the cover member 213, and the cover flange 213c abuts against the shell flange 212c via a sealing member such as an O-ring (not shown). This prevents rainwater and the like from entering the housing 211.

[0287] With the cover member 213 mounted on the gearbox 212, the substrate holding portion 213a faces the support portion 212d of the gearbox 212 along the axial direction of the output shaft 233. Furthermore, the sensor substrate 240 is fixed to the inside of the substrate holding portion 213a by a plurality of fixing screws (not shown). That is, the substrate holding portion 213a holds the sensor substrate 240 via a plurality of fixing screws.

[0288] Furthermore, a connector connection portion 213d is integrally provided in the substrate holding portion 213a for connection to an external connector (not shown) on the vehicle side. Inside the connector connection portion 213d, multiple terminal members 213e ( Figure 32 Only two of them are shown in the diagram, with one end exposed. In addition, the other end of these terminal members 213e is electrically connected to the sensor substrate 240.

[0289] Furthermore, a portion of the multiple terminal components 213e supplies drive current to the brushless motor 220, while the other terminal components 213e send signals indicating the operating status of the motor 210 with a reduction gear to the vehicle controller (not shown) via an external connector. Thus, the motor 210 with the reduction gear is controlled by the vehicle controller, causing the wiper component fixed to the front end of the output shaft 233 to swing within a predetermined wiping range on the windshield.

[0290] On the sensor substrate 240, one end is electrically connected to a plurality of motor terminal members 213f, and the other end of these motor terminal members 213f is electrically connected to the brushless motor 220. Specifically, three motor terminal members 213f are provided corresponding to each of the U-phase, V-phase, and W-phase coils 221b of the brushless motor 220 (see reference). Figure 35 ).

[0291] Moreover, such as Figure 31 As shown, three Hall integrated circuits (ICs) 241 and one magnetoresistive (MR) sensor 242 are mounted on the sensor substrate 240. The three Hall ICs 241 are mounted on the surface (one side) 240a of the sensor substrate 240, and the MR sensor 242 is mounted on the back (the other side) 240b of the sensor substrate 240.

[0292] More specifically, three Hall effect ICs 241 are arranged at predetermined intervals near the edge of surface 240a, facing the first sensor magnet MG12 disposed on rotor 222 from the axial direction of pinion 231. Here, rotor 222 is fixed to pinion 231; in other words, the first sensor magnet MG12 is disposed on pinion 231 via rotor 222. Thus, the three Hall effect ICs 241 are arranged at the same distance t22 relative to the first sensor magnet MG12 (see reference). Figure 35 () part.

[0293] On the other hand, the MR sensor 242 is disposed approximately in the central portion of the back surface 240b, facing the second sensor magnet MG22 located at the rotation center of the helical gear 232 from the axial direction of the pinion 231. Furthermore, as... Figure 35 As shown, the distance t12 between the MR sensor 242 and the second sensor magnet MG22 is approximately the same as the distance t22 between the three Hall ICs 241 and the first sensor magnet MG12 (t12≈t22). That is, the sensor substrate 240 is positioned between the first sensor magnet MG12 and the second sensor magnet MG22 while the motor 210 with a reduction mechanism is mounted on it.

[0294] In addition, these Hall ICs 241 and MR sensors 242 capture the changes in magnetic flux that accompany the rotation of the first sensor magnet MG12 and the second sensor magnet MG22, and send rectangular waves (pulse signals) to the vehicle controller.

[0295] Therefore, the vehicle controller measures the number of times or the timing of pulse signals from the Hall IC 241 and the MR sensor 242 to determine the rotational state (rotational speed or direction, etc.) of the brushless motor 220 (pinion 231), and controls the brushless motor 220 accordingly. In addition, the vehicle controller also measures the rotational state of the output shaft 233 (the position of the wiper assembly relative to the windshield, etc.), and controls the brushless motor 220 accordingly.

[0296] In addition, the signal sent by the MR sensor 242 can also be a stepped signal or a sine wave, etc.

[0297] With the cover member 213 installed on the gearbox 212, the motor housing 213b is positioned to the side opposite to the gearbox 212 side. Figure 32 The upper side of the motor housing 213b protrudes outwards. Furthermore, when the cover member 213 is installed in the gearbox 212, the motor housing 213b faces the bearing member housing 212f of the gearbox 212. In addition, the stator core 221 of the brushless motor 220 is fixed inside the motor housing 213b.

[0298] Furthermore, a bearing retainer 213g is provided in the central portion of the motor housing 213b, and the bearing retainer 213g is disposed radially inside the rotor 222. Inside the bearing retainer 213g, a second ball bearing BR22 that rotatably supports the base end side of the pinion 231 is housed.

[0299] like Figure 31 , Figure 32 , Figure 36 and Figure 37 As shown, the brushless motor 220 housed in the motor housing 213b includes an annular stator core 221. Furthermore, the stator core 221 is fixed inside the motor housing 213b in an anti-rotation state (details not shown).

[0300] The stator core 221 is formed by stacking multiple thin steel plates (magnetic bodies), and has multiple teeth 221a on its radially inner side. Here, in this embodiment, there are 12 teeth 221a (12 slots). In addition, U-phase, V-phase, and W-phase coils 221b are wound around these teeth 221a with a predetermined number of turns respectively by concentrated winding.

[0301] Therefore, compared with distributed winding of the coil across multiple slots, the increase in the axial dimension of the stator core 221 can be effectively suppressed. That is, in this embodiment, by employing a concentrated-winding brushless motor 220, the brushless motor 220 is miniaturized (thinned).

[0302] In addition, by alternately supplying drive current to the coils 221b of the U phase, V phase, and W phase at predetermined times, the rotor 222 located on the radially inner side of the stator core 221 is rotated in a predetermined direction with a predetermined drive torque.

[0303] A rotor 222 is rotatably mounted on the radially inner side of the stator core 221, separated by a tiny gap (air gap). The rotor 222 rotates the pinion 231 and includes a rotor body 222a whose cross-section is formed into a roughly U-shape by pressing a steel plate (magnetic body) or other processes. Furthermore, a first sensor magnet (permanent magnet) MG12, formed into a roughly cylindrical shape, is mounted on the radially outer side of the rotor body 222a.

[0304] Here, as described above, the first sensor magnet MG12 is used to detect the rotational state of the brushless motor 220 and also to drive the rotation of the rotor 222. That is, the first sensor magnet MG12 becomes a permanent magnet that serves two functions: a sensor and a drive mechanism. In addition, the first sensor magnet MG12 is magnetized by alternating N poles, S poles, ... along its circumference, and is firmly fixed to the rotor body 222a in a rotatable manner using adhesives or the like.

[0305] Thus, the brushless motor 220 of this embodiment is a surface permanent magnet (SPM) structure brushless motor with a permanent magnet (first sensor magnet MG12) fixed on the radially outer surface of the rotor body 222a. Here, the number of poles of the first sensor magnet MG12 can be arbitrarily set to two poles or more, depending on the specifications of the brushless motor 220.

[0306] Furthermore, a second ball bearing BR22 is provided on the radially inner side of the rotor body 222a that forms the rotor 222, which rotatably supports the pinion 231. Thus, as... Figure 36 As shown, the second ball bearing BR22 is disposed within the height dimension h2 of the rotor 222 and within the radial dimension d2 of the rotor 222. That is, when the rotor body 222a is viewed from the radial outside, the second ball bearing BR22 is obscured by the rotor body 222a.

[0307] Therefore, the axial dimension of the brushless motor 220 can be shortened, thereby suppressing the increase in the axial dimension of the motor 210 with the reduction mechanism along the output shaft 233, and realizing the miniaturization of the motor 210 with the reduction mechanism.

[0308] like Figure 31 , Figure 32 and Figure 38As shown, the reduction mechanism 230, rotatably housed within the gearbox 212, includes a pinion (first gear) 231 formed in a generally rod shape and a helical gear (second gear) 232 formed in a generally disk shape. Here, the axes of the pinion 231 and the helical gear 232 are parallel to each other. That is, the pinion 231 is parallel to the output shaft 233. Therefore, compared to a worm gear reducer that includes a worm and a worm wheel with intersecting axes, the reduction mechanism 230 can be made more compact.

[0309] Furthermore, the pinion 231 is disposed on the input side (drive source side) of the motor 210 with the reduction mechanism, and the helical gear 232 is disposed on the output side (drive object side) of the motor 210 with the reduction mechanism. That is, the reduction mechanism 230 reduces the high-speed rotation of the pinion 231 with fewer teeth to the low-speed rotation of the helical gear 232 with more teeth. Therefore, the helical gear 232 rotates at a lower speed than the pinion 231.

[0310] Here, the base end (axial end) of the pinion 231 is securely fixed to the center portion of the rotor body 222a and the second ball bearing BR22 by pressing or the like, and the pinion 231 rotates integrally with the rotor 222. That is, the pinion 231 also functions as the rotating shaft of the motor 210 with a reduction mechanism. Moreover, the front end of the pinion 231 is securely fixed to the center portion of the first ball bearing BR12 by pressing or the like.

[0311] The pinion 231 forming the reduction mechanism 230 is made of metal and is in the shape of... Figure 32 and Figure 38 The shape is as shown. Specifically, a helical tooth 231a is integrally provided around the pinion 231, and the axial length of the helical tooth 231a is set to be slightly longer than the axial length of the helical gear 232. Thus, the helical tooth 231a reliably meshes with the helical gear 232.

[0312] The helical tooth 231a extends continuously in a helical shape along the axial direction of the pinion 231, and there is only one helical tooth 231a on the pinion 231. That is, the number of teeth on the pinion 231 is set to "1". In addition, the helical tooth 231a is formed in such a way that its cross-section is circular along the direction orthogonal to the axial direction of the pinion 231, and it enters (meets) the meshing recess 232c of the helical gear 232.

[0313] The helical gear 232 forming the reduction mechanism 230 is made of plastic and is in the shape of... Figure 32 and Figure 38The shape is as shown. Specifically, the helical gear 232 includes a gear body 232a formed in a generally disc shape, and the base end side of the output shaft 233 is firmly fixed to the center of rotation of the gear body 232a by pressing or the like. Thus, the output shaft 233 rotates integrally with the helical gear 232.

[0314] Furthermore, on the sensor substrate 240 side of the gear body 232a ( Figure 32 On the upper side of the output shaft 233, a first recess 232a1 is provided, which is shallowly recessed along the axial direction of the output shaft 233. A second sensor magnet MG22 is fixed in the center of the first recess 232a1. Furthermore, the depth of the first recess 232a1 is slightly larger than the thickness of the second sensor magnet MG22, so that when the helical gear 232 is viewed radially outward, the second sensor magnet MG22 is obscured by the helical gear 232. This also enables miniaturization of the motor 210 with the reduction mechanism.

[0315] On the other hand, on the side of the gear body 232a opposite to the sensor substrate 240 side, that is, on the portion of the gear body 232a facing the bottom wall portion 212a ( Figure 32 On the lower side of the output shaft 233, a second recess 232a2 is formed that is deeply recessed along the axial direction of the output shaft 233. The depth of the second recess 232a2 is greater than the depth of the first recess 232a1. Additionally, as... Figure 32 As shown, the second cylindrical portion 212d2 of the support portion 212d and the plurality of second reinforcing ribs RB22 enter the interior of the second recess 232a2. This also enables the miniaturization of the motor 210 with the reduction mechanism.

[0316] Furthermore, on the outer periphery of the gear body 232a, a plurality of helical teeth 232b are integrally provided in a manner arranged along the circumferential direction of the gear body 232a. These helical teeth 232b are inclined at a predetermined angle relative to the axial direction of the pinion 231, thereby causing the helical gear 232 to rotate along with the rotation of the helical teeth 231a. Specifically, meshing recesses 232c are provided between adjacent helical teeth 232b, and the helical teeth 231a engage with each other by entering the meshing recesses 232c. In addition, the meshing recesses 232c are also formed in a circular (approximately arc-shaped) cross-section along a direction orthogonal to the axial direction of the output shaft 233.

[0317] Here, the number of helical teeth 232b (meshing recesses 232c) provided on the helical gear 232 is "40". That is, in this embodiment, the reduction ratio of the reduction mechanism 230, which includes the pinion 231 and the helical gear 232, is set to "40".

[0318] As detailed above, according to this embodiment, the support portion 212d that rotatably supports the output shaft 233 protrudes outward and inward of the gearbox 212 on one side of its length direction and the other side of its length direction, respectively. A first reinforcing rib RB12 and a second reinforcing rib RB22 are respectively provided between the first cylindrical portion 212d1 forming one side of the support portion 212d and the bottom wall portion 212a, and between the second cylindrical portion 212d2 forming the other side of the support portion 212d and the bottom wall portion 212a to improve the fixing strength of the support portion 212d to the bottom wall portion 212a.

[0319] Therefore, the excessive protrusion of the support portion 212d from the bottom wall portion 212a of the gearbox 212 to the outside of the gearbox 212 can be suppressed without reducing the strength of the gearbox 212. Therefore, the thickness dimension of the motor 210 with the reduction mechanism along the axial direction of the output shaft 233 can be shortened, thereby improving the versatility of the motor 210 with the reduction mechanism.

[0320] Furthermore, according to this embodiment, the pinion 231 and the output shaft 233 are arranged parallel to each other. In the portion of the helical gear 232 facing the bottom wall portion 212a, there is a second recess 232a2 that is recessed along the axial direction of the output shaft 233, and the second reinforcing rib RB22 enters the second recess 232a2.

[0321] Therefore, the thickness dimension of the motor 210 with the reduction mechanism along the axial direction of the output shaft 233 can also be shortened, thereby improving the versatility of the motor 210 with the reduction mechanism.

[0322] Furthermore, according to this embodiment, the pinion 231 forming the reduction mechanism 230 includes only one helical tooth 231a, thus increasing the reduction ratio compared to having multiple teeth.

[0323] Therefore, a small brushless motor 220 can be used, which in turn makes the motor 210 with the reduction mechanism even smaller.

[0324] Furthermore, according to this embodiment, a rotor 222 is provided at the axial end of the pinion 231 to rotate the pinion 231, and a second ball bearing BR22 is provided on the radial inner side of the rotor 222 to rotatably support the pinion 231.

[0325] Therefore, the second ball bearing BR22 can be concealed on the radial inner side of the rotor 222, which can shorten the axial dimension of the brushless motor 220.

[0326] Furthermore, according to this embodiment, a first sensor magnet MG12 and a second sensor magnet MG22 are respectively provided on the pinion 231 and the helical gear 232. A sensor substrate 240 is provided between the first sensor magnet MG12 and the second sensor magnet MG22. On the surface 240a of the sensor substrate 240, three Hall ICs 241 are provided facing the first sensor magnet MG12 from the axial direction of the pinion 231. On the back side 240b of the sensor substrate 240, an MR sensor 242 is provided facing the second sensor magnet MG22 from the axial direction of the pinion 231.

[0327] Therefore, the three Hall ICs 241 can be positioned at the same distance t22 relative to the first sensor magnet MG12. This allows the three Hall ICs 241 to operate reliably under the same conditions, enabling the vehicle controller to detect the rotational state of the pinion 231 with high precision.

[0328] Furthermore, the three Hall effect ICs 241 and one MR sensor 242 can be mounted on the surface 240a and back surface 240b of the same sensor substrate 240, respectively, thus eliminating the need to house multiple sensor substrates inside the housing 211. Therefore, the increase in the number of components can be suppressed, allowing the motor 210 with the reduction mechanism to be smaller and lighter.

[0329] This invention is not limited to the described embodiments, and various modifications can be made without departing from its spirit. For example, the described embodiment shows that the motor 210 with a reduction mechanism is suitable as a drive source for a windshield wiper unit mounted on a vehicle, but the invention is not limited thereto and can also be applied to other drive sources such as power window units or sunroof units.

[0330] Furthermore, the embodiment shown includes a motor 210 with a reduction mechanism that includes a brushless motor 220, but the present invention is not limited thereto, and a brushed motor may also be used as the motor unit.

[0331] In addition, the material, shape, size, number, and placement of each structural element in the above embodiments are arbitrary as long as they achieve the present invention, and are not limited to the above embodiments.

[0332] Industrial availability

[0333] Speed ​​reduction mechanisms and motors with speed reduction mechanisms can be used as drive sources for things like windshield wiper systems or power window systems in automobiles and other vehicles.

Claims

1. A speed reduction mechanism characterized by, It includes a first gear and a second gear, and has the following characteristics: The meshing protrusion is provided on the first gear and is formed into an arc shape with a first radius of curvature along the rotation direction of the first gear; as well as A meshing recess is provided on the second gear for the meshing protrusion to engage. The engagement recess includes: The bottom is located at the center of the meshing recess along the rotation direction of the second gear; as well as Sidewall portions are provided on both sides of the bottom along the rotation direction of the second gear. The sidewall portion becomes an arc-shaped concave or convex portion with a second radius of curvature larger than the first radius of curvature.

2. The deceleration mechanism according to claim 1, wherein, The size of the second radius of curvature is at least twice the size of the first radius of curvature.

3. The deceleration mechanism according to claim 1, wherein, A lubricating oil retaining portion is provided between the engaging protrusion and the bottom, and the lubricating oil retaining portion retains lubricating oil.

4. The deceleration mechanism according to claim 1, wherein, An accumulation portion is provided between the engagement protrusion and the bottom, the accumulation portion narrowing the gap formed between the engagement protrusion and the bottom.

5. A motor with a speed reduction mechanism, characterized by comprising: include: The speed reduction mechanism as described in any one of claims 1-4; and A rotating shaft that drives the first gear to rotate.

6. A reduction mechanism characterized by, It includes a first gear and a second gear, and has the following characteristics: The meshing protrusion is provided on the first gear and is formed in an arc shape along the rotation direction of the first gear; as well as A meshing recess is provided on the second gear for the meshing protrusion to engage. The engagement recess includes: The bottom is located at the center of the meshing recess along the rotation direction of the second gear; as well as Sidewall portions are provided on both sides of the bottom along the rotation direction of the second gear. The sidewall portion forms a plane that extends straight from the bottom.

7. The speed reduction mechanism according to claim 6, wherein, A lubricating oil retaining portion is provided between the engaging protrusion and the bottom, and the lubricating oil retaining portion retains lubricating oil.

8. The deceleration mechanism according to claim 6, wherein, An accumulation portion is provided between the engagement protrusion and the bottom, the accumulation portion narrowing the gap formed between the engagement protrusion and the bottom.

9. A motor with a speed reduction mechanism, characterized by comprising: include: The deceleration mechanism as described in any one of claims 6-8; and A rotating shaft that drives the first gear to rotate.

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