阅读说明：本技术 带减速机构的马达 (Motor with speed reducing mechanism ) 是由 内村浩之 熊仓亮 荻野成人 西健 于 2018-03-15 设计创作，主要内容包括：本发明在蜗轮46的轴方向一侧设置有朝向蜗轮46的轴方向另一侧凹陷的第一减料部46e,并且在蜗轮46的轴方向一侧设置有加强蜗轮46的第一减料部46e与齿部45之间的加强部46h。因此,利用第一减料部46e可以实现蜗轮46的轻量化,并且可以抑制齿部45产生变形。另外,利用加强部46h,可以充分地提高蜗轮46的齿部45附近的强度。(The present invention is provided with a first material reducing portion 46e recessed toward the other axial side of the worm wheel 46 on one axial side of the worm wheel 46, and a reinforcing portion 46h reinforcing between the first material reducing portion 46e of the worm wheel 46 and the tooth portion 45 on one axial side of the worm wheel 46. Therefore, the weight of the worm wheel 46 can be reduced by the first material reducing portion 46e, and the deformation of the tooth portion 45 can be suppressed. Further, the strength of the worm wheel 46 in the vicinity of the tooth portion 45 can be sufficiently increased by the reinforcing portion 46 h.)

1. A motor with a speed reduction mechanism that reduces and outputs rotation of an armature shaft, comprising:

a worm rotated by the armature shaft;

a worm wheel having a tooth portion engaged with the worm;

a one-side material reducing part which is arranged on one side of the axial direction of the worm wheel and is sunken towards the other side of the axial direction of the worm wheel; and

and a reinforcing part which is arranged on one side of the worm wheel in the axial direction and reinforces the space between the material reducing part on one side of the worm wheel and the tooth part.

2. The motor with reduction mechanism of claim 1, wherein

A bulging portion bulging outward in a diameter direction of the worm wheel than other portions of the tooth portion is provided at a portion of the tooth portion in an axial direction of the worm wheel, the portion being close to the reinforcing portion.

3. The motor with reduction mechanism of claim 1, wherein

The one-side material reducing portion is provided on the inner side in the diameter direction of the worm wheel than the reinforcing portion,

the one-side material reducing portion and the reinforcing portion overlap each other when the worm wheel is viewed in a diameter direction.

4. The motor with reduction mechanism of claim 3, wherein

The other side of the worm wheel in the axial direction is provided with a material reducing part at the other side which is sunken towards one side of the worm wheel in the axial direction,

the other side material reducing part is arranged at the same position with the one side material reducing part along the diameter direction of the worm wheel.

5. The motor with reduction mechanism of claim 4, wherein

The material reducing parts on one side and the material reducing parts on the other side are arranged in a staggered mode in the circumferential direction of the worm wheel.

6. The motor with reduction mechanism of claim 3, wherein

One longitudinal side of the tooth portion is provided closer to the other axial side of the worm wheel than the one longitudinal side of the one material reducing portion,

the reinforcing portion is inclined so as to descend toward the other side in the axial direction of the worm wheel as it goes toward the outer side in the radial direction of the worm wheel.

7. The motor with reduction mechanism of claim 3, wherein

A torque receiving portion for receiving the output member and a receiving portion for receiving the damping fin of the damping member are provided on the inner side of the worm wheel in the diameter direction than the one material reducing portion,

the accommodating portion is provided with a torque output portion that transmits the rotational force of the worm wheel to the torque receiving portion via the damper.

Technical Field

The present invention relates to a motor with a reduction mechanism that reduces and outputs rotation of an armature shaft.

Background

Conventionally, a motor with a speed reduction mechanism, which is small but can obtain a large output, has been used as a drive source for a power window device, a sunroof device, or the like mounted on a vehicle such as an automobile. The motor with the speed reduction mechanism is driven by an operation of an operation switch or the like in the vehicle interior, thereby opening and closing a window glass, a sunroof, or the like.

For example, patent document 1 discloses a motor with a speed reduction mechanism used as a drive source for a power window device, a sunroof device, or the like. The motor with a reduction mechanism described in patent document 1 includes a motor portion and a gear portion. The motor portion is provided with an armature shaft, and the gear portion is provided with a worm that rotates by the armature shaft and a worm wheel that includes a tooth portion that meshes with the worm.

Further, among the components constituting the motor with the speed reduction mechanism, a worm wheel is a large-sized component, and a resin worm wheel is also used in order to reduce the weight. On the other hand, in the case of a resin worm wheel, there is a possibility that defects such as "sink marks" and "voids" may occur during molding. In order to prevent the occurrence of the above-described problem, material reducing portions recessed in the axial direction of the worm wheel are provided at one axial side and the other axial side of the worm wheel, respectively, and at wall thickness portions near the gear teeth. Thereby, the weight of the worm wheel is reduced, and the deformation of the gear teeth is prevented.

Disclosure of Invention

Problems to be solved by the invention

However, when the motor with a speed reduction mechanism described in patent document 1 is applied to a vehicle having a heavy window glass such as a small van, the following problems may occur.

For example, when the window glass is closed, a large load (weight of the window glass) is applied to the worm wheel in the rotational direction thereof. At this time, the worm stops, and therefore the rotation force of the worm wheel does not rotate the worm. Therefore, a large load applied to the rotation direction of the worm wheel acts to expand the pitch between the gear teeth of the worm wheel.

As described above, in order to prevent the generation of the "sink mark" or the "void", a plurality of material reducing portions are provided in the vicinity of the gear teeth. Therefore, when the gear is applied to a vehicle having a heavy window glass such as a small van, the strength near the gear teeth may be insufficient. In other words, the worm wheel of the motor with a speed reduction mechanism described in patent document 1 is excellent in formability but may be insufficient in strength.

The invention aims to provide a motor with a speed reducing mechanism, which not only realizes the light weight of a worm wheel and the improvement of forming precision, but also fully improves the strength of the worm wheel.

Means for solving the problems

In one aspect of the present invention, a motor with a reduction mechanism that reduces and outputs rotation of an armature shaft includes: a worm rotated by the armature shaft; a worm wheel having a tooth portion engaged with the worm; a one-side material reducing part which is arranged on one side of the axial direction of the worm wheel and is sunken towards the other side of the axial direction of the worm wheel; and a reinforcing portion provided on one side of the worm wheel in the axial direction, the reinforcing portion reinforcing a space between the material reducing portion on the one side of the worm wheel and the tooth portion.

In another aspect of the present invention, a bulging portion that bulges outward in a diameter direction of the worm wheel than other portions of the tooth portion is provided in a portion of the tooth portion in an axial direction of the worm wheel, the portion being close to the reinforcing portion.

In another aspect of the present invention, the one-side material reducing portion is provided on a radially inner side of the worm wheel than the reinforcing portion, and the one-side material reducing portion and the reinforcing portion overlap each other when the worm wheel is viewed in a radial direction.

In another aspect of the present invention, the other-side material reducing portion is provided on the other axial side of the worm wheel so as to be recessed toward the one axial side of the worm wheel, and the other-side material reducing portion is provided at the same position as the one-side material reducing portion in the diameter direction of the worm wheel.

In another aspect of the present invention, the one-side material reducing portion and the other-side material reducing portion are arranged in a staggered manner in a circumferential direction of the worm wheel.

In another aspect of the present invention, one longitudinal side of the tooth portion is provided on the other axial side of the worm wheel than the one longitudinal side of the one material reducing portion, and the reinforcing portion is inclined so as to descend toward the other axial side of the worm wheel as it goes toward the outer radial side of the worm wheel.

In another aspect of the present invention, a torque receiving portion for receiving an output member and a damper piece of a damper member are provided on the worm wheel on the inner side in the diameter direction than the one material reducing portion, and a torque output portion that transmits the rotational force of the worm wheel to the torque receiving portion via the damper piece is provided in the receiving portion.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, the one-side material reducing portion that is recessed toward the other side in the axial direction of the worm wheel is provided on one side in the axial direction of the worm wheel, and the reinforcing portion that reinforces the one-side material reducing portion of the worm wheel and the tooth portion is provided on one side in the axial direction of the worm wheel.

Therefore, the weight of the worm wheel can be reduced by the one-side material reducing portion, and the deformation of the tooth portion can be suppressed. Further, the strength near the tooth portion of the worm wheel can be sufficiently increased by the reinforcing portion.

Drawings

Fig. 1 is a partial sectional view showing a motor with a reduction mechanism of the present invention.

Fig. 2 is a sectional view taken along line a-a of fig. 1.

Fig. 3 is an exploded perspective view showing the worm wheel, the damping member, and the output member.

Fig. 4(a) and (b) are plan views illustrating detailed configurations of the front and back sides of the worm wheel.

Fig. 5 is a sectional view taken along line B-B of fig. 4 (a).

Fig. 6 is an enlarged view of a dotted circle C in fig. 4 (a).

Fig. 7 is a partially enlarged view of the worm wheel as viewed from the side.

Fig. 8 is a cross-sectional view of the worm wheel according to embodiment 2 corresponding to fig. 5.

Detailed Description

Hereinafter, embodiment 1 of the present invention will be described in detail with reference to the drawings.

Fig. 1 is a partial sectional view showing a motor with a reduction gear mechanism according to the present invention, fig. 2 is a sectional view taken along line a-a of fig. 1, fig. 3 is an exploded perspective view showing a worm wheel, a damping member and an output member, fig. 4(a) and (B) are plan views illustrating detailed configurations of a front surface side and a back surface side of the worm wheel, fig. 5 is a sectional view taken along line B-B of fig. 4(a), fig. 6 is an enlarged view of a dotted circle C portion of fig. 4(a), and fig. 7 is a partially enlarged view of the worm wheel as viewed from a side.

A motor 10 with a speed reduction mechanism shown in fig. 1 is used as a drive source of an electric window device mounted in a vehicle such as an automobile, and drives a window regulator (not shown) that raises and lowers a window glass. The motor 10 with a speed reduction mechanism is provided in a small space in a door of a vehicle, and therefore has a flat shape as shown in fig. 2. The motor 10 with a reduction mechanism includes a motor portion 20 and a gear portion 40, and the motor portion 20 and the gear portion 40 are integrated (unitized) with each other by a plurality of fastening screws 11 (only two of which are shown in fig. 1).

As shown in fig. 1, the motor section 20 includes a motor housing 21. The motor case 21 is formed in a bottomed tubular shape by deep drawing or the like of a steel plate containing a magnetic material. A plurality of magnets 22 (only two magnets are shown in the drawing) having a substantially circular arc-shaped cross section are provided inside the motor housing 21.

An armature 24 around which a coil 23 is wound is rotatably provided inside each magnet 22 with a predetermined gap therebetween. Further, a brush holder 25 is mounted on the opening side (right side in the drawing) of the motor housing 21, and the brush holder 25 blocks the opening side of the motor housing 21.

An armature shaft 26 is fixed to the rotation center of the armature 24. A commutator (commutator)27 is provided at a portion of the armature shaft 26 close to the armature 24, and the commutator 27 is electrically connected to an end of the coil 23 wound around the armature 24.

The commutator 27 has an outer peripheral portion in sliding contact with a pair of brushes 28 held by the brush holder 25. Each brush 28 is elastically contacted to the commutator 27 by a spring member 29 with a predetermined pressure. Thus, a drive current is supplied from a vehicle controller (not shown) to each brush 28, and a rotational force (electromagnetic force) is generated in the armature 24. Therefore, the armature shaft 26 rotates in a predetermined rotational direction and rotational speed.

The bottom portion side (left side in the drawing) of the motor case 21 is formed in a stepped shape, and a stepped portion 21a having a smaller diameter than the body portion of the motor case 21 is provided in the stepped portion. A first radial bearing 30 is attached to the stepped-bottom portion 21a, and the first radial bearing 30 rotatably supports one side (left side in the drawing) in the axial direction of the armature shaft 26. Further, a first thrust bearing 31 is provided on the bottom side of the stepped-bottom portion 21a, and the first thrust bearing 31 regulates the movement of the armature shaft 26 in the axial direction.

A second radial bearing 32 is mounted on the brush holder 25. The second radial bearing 32 rotatably supports the axial center portion of the armature shaft 26.

The gear portion 40 includes a gear case 41 and a connector member 42 attached to the gear case 41. The gear case 41 is formed into a predetermined shape by injection molding of a resin material such as plastic, and is fixed to the opening side of the motor housing 21 by a plurality of fastening screws 11. The distal end of the connector member 42 is inserted into the side of the gear case 41, and is fixed to the gear case 41 by a pair of fixing screws 43 in this state.

The other axial side (right side in the drawing) of the armature shaft 26 extends into the gear case 41, and a worm 44 is fixed to the other axial side of the armature shaft 26 and an outer peripheral portion thereof. A worm wheel 46 is rotatably housed in the gear case 41, and a tooth portion 45 that meshes with the worm 44 is provided on the outer peripheral portion of the worm wheel 46. Here, the worm 44 is formed in a spiral shape, and the tooth portion 45 is inclined at a gentle inclination angle in the axial direction of the worm wheel 46. Thereby, the rotational force of the worm 44 is smoothly transmitted to the worm wheel 46.

A second thrust bearing 47 is provided inside the gear case 41 on the other axial side of the armature shaft 26, and the second thrust bearing 47 regulates the axial movement of the armature shaft 26. The other axial side of the armature shaft 26 is rotatably supported by a third radial bearing 48.

In this way, by providing the first radial bearing 30 and the first thrust bearing 31 on one side in the axial direction of the armature shaft 26, the second radial bearing 32 on the center portion in the axial direction of the armature shaft 26, and the third radial bearing 48 and the second thrust bearing 47 on the other side in the axial direction of the armature shaft 26, the armature shaft 26 (the armature 24) can be rotated efficiently and smoothly.

An annular sensor magnet 49 is integrally provided between the commutator 27 and the second radial bearing 32 along the axial direction of the armature shaft 26. The sensor magnet 49 has N and S poles magnetized in an alternating arrangement along the circumferential direction thereof. On the other hand, a sensor substrate 42a is provided inside the connector member 42, and a rotation sensor 42b is attached to a portion of the sensor substrate 42a facing the sensor magnet 49.

Here, the rotation sensor 42b is a magnetic sensor that captures the direction of the magnetic flux lines of the sensor magnet 49 and the change thereof. Thereby, the rotation sensor 42b can detect the rotation state of the armature shaft 26, that is, the rotation direction and the rotation speed of the armature shaft 26. More specifically, the rotation sensor 42b includes a magnetoresistive element (MR) element) as a sensor element, and is a Giant Magnetoresistive (GMR) sensor to which a Giant magnetoresistive effect phenomenon (Giant magnetoresistive effect) is applied.

The vehicle-mounted controller detects a detection signal from the rotation sensor 42b and calculates the rotation state of the armature shaft 26. For example, when the rotation speed of the armature shaft 26 decreases, the vehicle-mounted controller determines that the window glass is in contact with an obstacle. Then, control is performed to stop or reverse the rotational driving of the motor 10 with the speed reduction mechanism.

As shown in fig. 2, a support tube 41b that rotatably supports the worm wheel 46 is integrally provided on the bottom portion 41a of the gear case 41. The support cylinder 41b protrudes toward the inside of the gear case 41, and rotatably supports an output shaft 71 forming the output member 70 on the inside in the diameter direction of the support cylinder 41 b. The distal end side (lower side in the drawing) of the output shaft 71 is exposed to the outside of the gear case 41.

As shown in fig. 2 and 3, a damping member 60 and an output member 70 are attached to the worm wheel 46. The worm wheel 46, the damping member 60, and the output member 70 are attached from the opening side (upper side in fig. 2) of the gear case 41 in an integrated state, that is, in a sub-assembly state. In this way, the worm wheel 46, the damping member 60, and the output member 70 are integrated (sub-assembled) to improve the assembly workability of the motor 10 with the speed reduction mechanism.

The damper member 60 is formed of an elastic material such as rubber, and includes a ring-shaped body portion 61 and six damper pieces 62 integrally provided to the body portion 61. The six damper pieces 62 are provided at substantially equal intervals (substantially 60-degree intervals) in the circumferential direction of the body portion 61, and project outward in the diameter direction of the body portion 61. Here, the damper member 60 including the body portion 61 and the six damper pieces 62 is accommodated in the accommodating portion SP of the worm wheel 46 (see fig. 3).

Further, three torque output portions 46d integrally provided to the worm wheel 46 and three torque receiving portions 72a (only two are shown in fig. 3) integrally provided to the disc member 72 of the output member 70 alternately enter between the adjacent damper pieces 62, respectively, in the circumferential direction of the damper member 60. Thus, when the worm wheel 46 rotates in the forward and reverse directions, the rotational torque is transmitted from the torque output portion 46d to the torque receiving portion 72a via the damper plate 62. At this time, the damper sheet 62 is elastically deformed, and the shock accompanying the rapid fluctuation of the rotational torque is alleviated.

The output member 70 includes a substantially cylindrical output shaft 71 made of steel or the like, and a seal ring SR is provided between the output shaft 71 and the support cylinder 41 b. This prevents rainwater and the like from entering the interior of the gear case 41 from the bottom portion 41a side. A bottomed substantially cubic coupling portion 71a is integrally provided at a distal end portion exposed to the outside of the output shaft 71. A drum (not shown) forming a window regulator is coupled to the coupling portion 71a so as to be able to transmit power.

A disc member 72 made of a resin material such as plastic is fixed to a base end portion of the output shaft 71 housed in the gear case 41. More specifically, a base material 73 made of steel is embedded in the center portion of the disc member 72 by insert molding, and the base material 73 is fixed to the base end portion of the output shaft 71 by serration fitting (not shown in detail). This allows the rotational force from the disc member 72 to be efficiently transmitted to the output shaft 71. The disc member 72 is retained from the output shaft 71 by the retainer R.

On the worm wheel 46 side (lower side in the figure) of the disc member 72, three torque receiving portions 72a that enter between the respective adjacent damper pieces 62, respectively, are integrally provided. The torque receiving portions 72a are arranged at substantially equal intervals (substantially 120-degree intervals) along the circumferential direction of the disc member 72. Here, the three torque receiving portions 72a are accommodated in the accommodating portions SP of the worm wheel 46.

The opening side (upper side in fig. 2) of the gear case 41 is closed by a case cover 80. The case cover 80 is formed into a substantially circular disk shape by press working or the like of a stainless steel plate, and a convex portion 81 that protrudes toward the output shaft 71 side is provided at the center portion thereof. The convex portion 81 slidably enters a concave portion 71b formed on the base end side of the output shaft 71. This prevents rainwater and the like from entering the gear case 41 from the opening side, and suppresses rotational vibration of the output shaft 71.

Here, to explain the power transmission path of the motor 10 with a speed reduction mechanism, first, the rotation of the armature shaft 26 is reduced by the worm 44 and the worm wheel 46 (speed reduction mechanism). Then, the decelerated and highly torqued rotational force is transmitted from the torque output portion 46d to the torque receiving portion 72a via the damping member 60. Thereafter, the rotational force is transmitted from the output shaft 71 to a gear or a drum provided in the window regulator coupled to the coupling portion 71a, thereby lifting and lowering the window glass.

As shown in fig. 2 to 7, the worm wheel 46 is formed in a bottomed cylindrical shape. Specifically, the worm wheel 46 is formed into a substantially disk shape by injecting a molten resin material into a cavity formed in each of the pair of upper and lower molds while aligning the molds. Further, the worm wheel 46 includes: a small-diameter cylindrical portion 46a rotatably attached to a support cylinder 41b of the gear case 41, a large-diameter cylindrical portion 46b having teeth 45 formed on the outer peripheral portion thereof, and a bottom portion 46c connecting the small-diameter cylindrical portion 46a and the large-diameter cylindrical portion 46 b.

An annular receiving portion SP is formed between the outer peripheral portion of the small-diameter cylindrical portion 46a and the inner peripheral portion of the large-diameter cylindrical portion 46b and the bottom portion 46 c. That is, the annular housing portion SP is provided on the inner side in the diameter direction of the worm wheel 46 than the first material reducing portion 46e provided on the large diameter cylindrical portion 46 b.

Further, three torque output portions 46d are provided inside the housing portion SP, and the three torque output portions 46d protrude in the axial direction of the worm wheel 46 and protrude inward in the diameter direction of the worm wheel 46. The torque output portion 46d is integrally provided on the worm wheel 46 and enters between the adjacent damper blades 62. The torque output portions 46d are formed in a substantially triangular shape that is pointed toward the small-diameter cylindrical portion 46a, and are arranged at substantially equal intervals (substantially 120-degree intervals) along the circumferential direction of the bottom portion 46 c.

Here, the three torque output portions 46d have the following functions: the rotational force of the worm wheel 46 is transmitted to the torque receiving portion 72a forming the output member 70 via the damper fin 62 of the damper member 60.

As shown in fig. 2 and 5, a plurality of first material reducing portions (one-side material reducing portions) 46e arranged in the circumferential direction of the worm wheel 46 are provided on one axial direction side (upper side in the drawing) of the large diameter cylindrical portion 46b in the vicinity of the teeth 45. The first material reducing portion 46e is recessed toward the other side (lower side in the drawing) in the axial direction of the worm wheel 46. The first material reducing portions 46e are provided in total in 24 on one side of the large diameter cylindrical portion 46b in the axial direction, at substantially equal intervals (at substantially 15-degree intervals) in the circumferential direction.

Further, a second material reducing portion (the other material reducing portion) 46f in which a plurality of material reducing portions are arranged in the circumferential direction of the worm wheel 46 is provided on the other axial side (the lower side in the drawing) of the large diameter cylindrical portion 46b in the vicinity of the tooth portion 45. The second material reducing portion 46f is recessed toward one side (upper side in the drawing) in the axial direction of the worm wheel 46. Further, a total of 24 second reducing portions 46f are provided on the other axial side of the large-diameter cylindrical portion 46b at substantially equal intervals (substantially 15-degree intervals) in the circumferential direction.

Here, the second material reducing portion 46f is provided at the same position as the first material reducing portion 46e in the diameter direction of the worm wheel 46. Further, the depth dimension d1 of the first material reducing portion 46e along the axial direction of the worm wheel 46 is a depth dimension (d1 ≈ 3 × d2) substantially 3 times the depth dimension d2 of the second material reducing portion 46f along the axial direction of the worm wheel 46.

Further, a meshing support portion 46g extending in the circumferential direction of the worm wheel 46 is provided between the first material reducing portion 46e and the second material reducing portion 46f along the axial direction of the worm wheel 46. The meshing support portion 46g is a portion that supports the meshing of the worm 44 with respect to the tooth portion 45, and secures the rigidity of the meshing center GC of the worm wheel 46. In other words, the engagement support portion 46g has a function of suppressing a decrease in rigidity of the worm wheel 46 due to the provision of the first material reducing portion 46e and the second material reducing portion 46 f.

The first and second material reducing portions 46e and 46f, each of which is provided with 24, are provided in the same phase in the circumferential direction of the large diameter cylindrical portion 46b (worm wheel 46). That is, as shown in fig. 5, the first material reducing portion 46e and the second material reducing portion 46f are provided at the same position along the circumferential direction of the large diameter cylindrical portion 46 b.

In this way, by providing the first and second reduced material portions 46e and 46f with the same phase in the circumferential direction of the large diameter cylindrical portion 46b, the wall thickness t1 of the first rib R1 between the adjacent first reduced material portions 46e and the wall thickness t2 of the second rib R2 between the adjacent second reduced material portions 46f are made thin and the wall thicknesses are made substantially uniform. The thickness t3 of the engagement support portion 46g is also substantially the same as the thickness t1 of the first rib R1 and the thickness t2 of the second rib R2. This effectively suppresses the occurrence of defects such as "sink marks" and "gaps" near the teeth 45.

As shown in fig. 3 and 7, a plurality of reinforcing portions 46h for reinforcing the space between the first reduced portion 46e of the worm wheel 46 and the tooth portion 45 are provided on one side in the axial direction of the large diameter cylindrical portion 46b (the worm wheel 46). The reinforcing portion 46h radially extends outward in the diameter direction about the small-diameter cylindrical portion 46a, and is disposed between a first reduced portion 46e provided on the inner side in the diameter direction of the worm wheel 46 and the tooth portion 45 provided on the outer side in the diameter direction of the worm wheel 46.

As shown by the thick two-dot chain line (imaginary line) in fig. 7, an annular step portion 46k extending in the circumferential direction of the worm wheel 46 is formed between the first blank reducing portion 46e and the tooth portion 45. Here, one longitudinal direction side (upper side in the drawing) of the tooth portion 45 is provided on the other axial direction side (lower side in the drawing) of the worm wheel 46 than the one longitudinal direction side (upper side in the drawing) of the first reduced material portion 46 e. Thereby, an annular step portion 46k is formed between the one longitudinal side of the tooth portion 45 and the one longitudinal side of the first reduced material portion 46 e. In addition, a total of 24 reinforcing portions 46h are provided at substantially equal intervals (substantially 15-degree intervals) in the circumferential direction of the annular step portion 46 k.

More specifically, as shown in fig. 7, the plurality of reinforcing portions 46h provided in the annular step portion 46k are inclined so as to descend toward the other axial side (lower side in the figure) of the worm wheel 46 as they go toward the outer radial side (right side in the figure) of the worm wheel 46. That is, the reinforcing portions 46h are inclined substantially in a staircase shape toward the outer side in the diameter direction of the worm wheel 46. In this way, the reinforcing portion 46h is inclined in a substantially trapezoidal manner, thereby preventing the outer contour of the worm wheel 46 from becoming large.

As shown in fig. 6, third material reducing portions 46m are formed between the adjacent reinforcing portions 46h, and the third material reducing portions 46m (24 in total) and the first material reducing portions 46e are arranged alternately in the circumferential direction of the worm wheel 46. Thus, the reinforcing portion 46h and the first material reducing portion 46e are respectively disposed on a line segment L1 extending in the diameter direction of the worm wheel 46 through the center portion of the worm wheel 46.

That is, the first material reducing portion 46e is provided on the inner side of the reinforcing portion 46h in the diameter direction of the worm wheel 46, and the first material reducing portion 46e and the reinforcing portion 46h overlap each other when the worm wheel 46 is viewed in the diameter direction.

Thus, the wall thickness t1 of the first rib R1 and the wall thickness t4 of the reinforcing portion 46h between the adjacent first reduced portions 46e are made thin and substantially uniform. The thickness t5 of the shoulder 46n between the first reduced material portion 46e and the reinforced portion 46h in the radial direction of the worm wheel 46 is also substantially the same as the thickness of the first rib R1 and the reinforced portion 46 h. Therefore, the strength of the portion is improved while suppressing the occurrence of defects such as "sink marks" or "gaps" near the first reduced material portion 46e and around the tooth portion 45.

As shown in fig. 3 and 7, a bulging portion 46p bulging outward in the radial direction of the worm wheel 46 than the other portion of the tooth portion 45 is provided in a portion of the tooth portion 45 in the axial direction of the worm wheel 46, the portion being close to the reinforcing portion 46 h. More specifically, the tooth 45 is formed of a linear tooth 45a and a curved tooth 45b, and the curved tooth 45b is disposed in the portion of the bulging portion 46 p.

Here, the protruding height of the bulging portion 46p to the outside in the diameter direction is set to H with reference to the tooth tip portion of the linear tooth portion 45 a. Specifically, the projection height H is set to a dimension of approximately 1/3 of the entire tooth height of the linear tooth portion 45 a. This increases the strength of the periphery of the curved tooth portion 45b of the worm wheel 46.

As shown in fig. 2, the worm 44 meshes with both the linear teeth 45a and the curved teeth 45b of the teeth 45. Therefore, the contact area of the meshing portion of the worm 44 and the tooth portion 45 is increased, and the meshing strength of both is improved. By increasing the meshing strength as described above, the stress concentration from the worm 44 to the tooth portion 45 is alleviated, early wear of the tooth portion 45 and loosening of both are eliminated, and the transmission efficiency of the rotational force is improved.

As described above in detail, according to the motor 10 with a reduction mechanism of the present embodiment, the first material reducing portion 46e that is recessed toward the other axial side of the worm wheel 46 is provided on one axial side of the worm wheel 46, and the reinforcing portion 46h that reinforces the tooth portion 45 and the first material reducing portion 46e of the worm wheel 46 is provided on one axial side of the worm wheel 46.

Therefore, the weight of the worm wheel 46 can be reduced by the first material reducing portion 46e, and the deformation of the tooth portion 45 can be suppressed. Further, the strength of the worm wheel 46 in the vicinity of the tooth portion 45 can be sufficiently increased by the reinforcing portion 46 h.

Further, according to the motor 10 with a reduction mechanism of the present embodiment, since the bulging portion 46p bulging further outward in the diameter direction of the worm wheel 46 than the other portion of the tooth portion 45 is provided in the portion of the tooth portion 45 close to the reinforcing portion 46h in the axial direction of the worm wheel 46, the strength of the periphery of the curved tooth portion 45b of the worm wheel 46 can be improved.

Further, by providing the bulging portion 46p, the teeth 45 can be formed by the linear teeth 45a and the curved teeth 45b, and the worm 44 can be meshed with both the linear teeth 45a and the curved teeth 45 b. Therefore, the contact area of the meshing portion between the worm 44 and the tooth 45 is increased, the meshing strength between the worm 44 and the tooth 45 is improved, the stress concentration from the worm 44 to the tooth 45 is alleviated, the early wear of the tooth 45 and the loosening of the tooth 45 are eliminated, and the transmission efficiency of the rotational force is improved.

In the motor 10 with a reduction mechanism according to the present embodiment, the first material reducing portion 46e is provided on the inner side of the reinforcing portion 46h in the diameter direction of the worm wheel 46, and the first material reducing portion 46e and the reinforcing portion 46h overlap each other when the worm wheel 46 is viewed in the diameter direction.

Thus, the thickness t1 of the first rib R1 and the thickness t4 of the reinforcing portion 46h can be made thin and substantially uniform. The thickness t5 of the shoulder portion 46n may be substantially the same as the thickness of the first rib R1 and the reinforcing portion 46 h. Therefore, it is possible to suppress occurrence of defects such as "sink marks" or "gaps" in the vicinity of the first reduced material portion 46e and around the tooth portion 45, and to improve the strength of the portion.

Further, according to the motor 10 with a reduction mechanism of the present embodiment, the second material reducing portion 46f that is recessed toward one side in the axial direction of the worm wheel 46 is provided on the other side in the axial direction of the worm wheel 46, and the second material reducing portion 46f is provided at the same position as the first material reducing portion 46e in the diameter direction of the worm wheel 46 and is provided at the same phase as the first material reducing portion 46e in the circumferential direction of the worm wheel 46.

Thus, the thickness t1 of the first rib R1 and the thickness t2 of the second rib R2 can be made thin and substantially uniform. The thickness t3 of the engagement support portion 46g may be substantially the same as the thickness of the first rib R1 and the second rib R2. Therefore, it is possible to more effectively suppress the occurrence of defects such as "sink marks" and "gaps" near the teeth 45.

Further, according to the motor 10 with a reduction mechanism of the present embodiment, one longitudinal side of the tooth portion 45 is provided on the other axial side of the worm wheel 46 than the one longitudinal side of the first reduced material portion 46e, and the reinforcing portion 46h is inclined so as to descend toward the other axial side of the worm wheel 46 as it goes toward the outer radial side of the worm wheel 46.

This makes it possible to incline the reinforcing portion 46h substantially like a slide toward the outside in the diameter direction of the worm wheel 46, and to prevent the outer shape of the worm wheel 46 from becoming large.

Further, according to the motor 10 with a speed reduction mechanism of the present embodiment, the accommodating portion SP that accommodates the torque receiving portion 72a of the output member 70 and the damper piece 62 of the damper member 60 is provided on the inner side in the diameter direction of the worm wheel 46 than the first material reducing portion 46e, and the torque output portion 46d that transmits the rotational force of the worm wheel 46 to the torque receiving portion 72a via the damper piece 62 is provided on the accommodating portion SP.

Thus, even if the rotational torque of the armature shaft 26 fluctuates rapidly, the shock associated therewith can be alleviated. Therefore, the quietness of the motor 10 with the speed reducing mechanism can be improved. In addition, the meshing portion of the worm 44 and the tooth portion 45 can be protected from impact, and the life of the motor 10 with the reduction mechanism can be extended.

Next, embodiment 2 of the present invention will be described in detail with reference to the drawings. Note that portions having the same functions as those in embodiment 1 are given the same reference numerals, and detailed description thereof is omitted.

Fig. 8 shows a cross-sectional view of the worm wheel according to embodiment 2, which corresponds to fig. 5.

As shown in fig. 8, a worm wheel 90 according to embodiment 2 is different from the worm wheel 46 (see fig. 5) according to embodiment 1 in that a plurality of first material reducing portions (one-side material reducing portions) 46e and a plurality of second material reducing portions (the other-side material reducing portions) 46f are arranged alternately on one axial side and the other axial side of the worm wheel 90 so as to alternately appear in the circumferential direction of the large-diameter cylindrical portion 46b (the worm wheel 90).

Specifically, the interval between the line segment L2 extending in the axial direction of the worm wheel 90 through the central portion of the first reduced material portion 46e and the line segment L3 extending in the axial direction of the worm wheel 90 through the central portion of the second reduced material portion 46f is substantially 7.5 degrees along the circumferential direction of the worm wheel 90.

The worm wheel 90 according to embodiment 2 formed as described above can also exhibit the same operational effects as those of embodiment 1.

In embodiment 2, since the first material reducing portions 46e and the second material reducing portions 46f are arranged alternately in the circumferential direction of the worm wheel 90, the wall thickness t6(═ d1) of the portion of the first rib R1 along the axial direction of the worm wheel 90 and the wall thickness t7(═ d2) of the portion of the second rib R2 along the axial direction of the worm wheel 90 can be reduced, respectively, as compared with embodiment 1.

Therefore, it is possible to more effectively suppress the occurrence of defects such as "sink marks" and "voids" near the teeth 45 (see fig. 2).

Of course, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. For example, in the above embodiments, the worm wheel 46 and the worm wheel 90 are formed by injection molding of a resin material such as plastic, but the present invention is not limited to this, and may be applied to a worm wheel made of another material that can generate "sink marks" or "voids", for example, a worm wheel formed by casting an aluminum material or the like.

In the above embodiments, the motor 10 with the speed reduction mechanism is used as the drive source of the power window device mounted on the vehicle, but the present invention is not limited to this, and may be used as another drive source such as a sunroof device.

In the above embodiments, the case where the electric motor with the brush is used for the motor unit 20 is described, but the present invention is not limited to this, and for example, a brushless electric motor or the like may be used for the motor unit 20.

The material, shape, size, number, installation location, and the like of each component of the above-described embodiments are arbitrary as long as the present invention can be achieved, and are not limited to the above-described embodiments.

Industrial applicability

A motor with a speed reduction mechanism is used as a drive source of a power window device mounted in a vehicle such as an automobile, and drives a window regulator that raises and lowers a window glass.