Motor with reduction mechanism

Abstract

To provide a motor with a speed reduction mechanism which is capable of improving water exposure resistance reliability by more reliably suppressing entry of rainwater or the like into the interior of a housing.SOLUTION: A pair of slits 93a and 93b extending in an axial direction of a tubular member 93 is provided to the tubular member 93, and opening widths of the pair of slits 93a and 93b in a circumferential direction of a cylindrical member 93 are smaller on an outer side (opening widths W2 and W4) than those on an inner side (opening widths W1 and W3) of the tubular member 93. As a result, rainwater or the like is restrained from reaching a communication hole 91 inside the tubular member 93, and rainwater or the like that has entered the tubular member 93 can be quickly discharged to the outside of the tubular member 93. Therefore, it is possible to effectively restrain rainwater or the like from entering an inside (hollow portion) of a gear cover 80, thereby improving the water exposure resistance reliability.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a motor with a reduction mechanism, which includes a motor section having a rotating shaft, and a reduction mechanism section having a reduction mechanism for reducing the rotation speed of the rotating shaft. [Background technology]

[0002] Motors with speed reduction mechanisms are used, for example, as drive sources for wiper devices and power window devices. In particular, motors with speed reduction mechanisms used as drive sources for wiper devices are installed in engine rooms with high-temperature atmospheres and are operated continuously for relatively long periods of time. As a result, the motors with speed reduction mechanisms become hot, and if they are exposed to water in this state, they will cool down rapidly. This will create negative pressure inside the housing, and there is a risk that rainwater or the like will enter the housing. Therefore, a motor with speed reduction mechanisms provided with a so-called "breathing function" to prevent the inside of the housing from becoming negative pressure is described, for example, in Patent Document 1.

[0003] The drive device (motor with speed reduction mechanism) described in Patent Document 1 includes a gear case (housing) and a cover (housing), and a speed reduction mechanism that reduces the rotation speed of a rotating shaft is housed inside the gear case and the cover. The cover is provided with an air vent that connects the inside and outside of the cover. This allows air to flow in and out freely through the air vent in response to pressure fluctuations inside the housing. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2016-086539 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the motor with a reduction gear mechanism described in the above-mentioned Patent Document 1, there was a risk of rainwater or the like entering through the ventilation hole depending on the mounting position of the motor with a reduction gear mechanism on the vehicle. Because a control board that controls the rotation state of the rotating shaft is provided inside the housing, it was necessary to more reliably prevent rainwater or the like from entering the inside of the housing.

[0006] An object of the present invention is to provide a motor with a reduction gear mechanism that can more reliably prevent rainwater, etc. from entering the inside of the housing, thereby improving water resistance. [Means for solving the problem]

[0007] In one aspect of the present invention, a motor with a reduction mechanism includes a motor section having a rotating shaft, and a reduction mechanism section having a reduction mechanism for reducing the rotation speed of the rotating shaft, the reduction mechanism including a housing for accommodating the reduction mechanism, a communication hole provided in the housing for communicating the inside and the outside of the housing, and a communication hole provided on the outside of the housing. and the housing. The cylindrical member has an inner portion that is connected to the communicating hole and an outer portion that is connected to the communicating hole, and a slit is provided in the cylindrical member and extends in the axial direction of the cylindrical member, and the opening width of the slit in the circumferential direction of the cylindrical member is narrower on the outer side than on the inner side of the cylindrical member. Effect of the Invention

[0008] According to the present invention, the cylindrical member is provided with a slit extending in the axial direction of the cylindrical member, and the opening width of the slit in the circumferential direction of the cylindrical member is narrower on the outer side than on the inner side of the cylindrical member. This prevents rainwater, etc. from reaching the communication hole inside the cylindrical member, and allows rainwater, etc. that has entered the inside of the cylindrical member to be quickly discharged to the outside of the cylindrical member. Therefore, rainwater, etc. is effectively prevented from entering the inside of the housing, and water damage reliability can be improved. [Brief description of the drawings]

[0009] [Figure 1]1 is a schematic diagram of a vehicle equipped with a wiper motor. [Diagram 2] FIG. 2 is a perspective view showing the wiper motor shown in FIG. [Diagram 3] 3 is a diagram showing an internal structure of the wiper motor shown in FIG. 2. [Figure 4] 3 is a cross-sectional view of the periphery of a cylindrical member taken along line AA in FIG. 2. [Diagram 5] 5 is a cross-sectional view of the periphery of the cylindrical member taken along line BB in FIG. 4. [Figure 6] 10A to 10C are perspective views showing a procedure for attaching a filter and a cap member to a cylindrical member. [Figure 7] 4 is a perspective view of the periphery of a cylindrical member, showing the flow of rainwater, etc. through the cylindrical member; FIG. [Figure 8] 11 is a cross-sectional view of the periphery of a cylindrical member in a wiper motor according to a second embodiment. FIG. [Figure 9] FIG. 11 is a plan view of a wiper motor according to a third embodiment. [Figure 10] FIG. 10 is an exploded perspective view showing the internal structure of the wiper motor shown in FIG. [Figure 11] 11 is a cross-sectional view of the tubular member and its periphery taken along line CC in FIG. 10. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0011] Figure 1 is a schematic diagram of a vehicle equipped with a wiper motor, Figure 2 is an oblique view of the wiper motor of Figure 1, Figure 3 is a diagram showing the internal structure of the wiper motor of Figure 2, Figure 4 is a cross-sectional view of the area around the tubular member taken along line AA of Figure 2, Figure 5 is a cross-sectional view of the area around the tubular member taken along line BB of Figure 4, Figure 6 is an oblique view showing the procedure for attaching a filter and a cap member to the tubular member, and Figure 7 is an oblique view of the area around the tubular member showing the flow of rainwater, etc. into the tubular member.

[0012] As shown in Fig. 1, a wiper device 20 is mounted in an engine room (not shown) at the front side of a vehicle 10 such as an automobile. The wiper device 20 swings a pair of wiper members 30 provided corresponding to a driver's seat side (Driver) and a passenger seat side (Assist). The wiper member 30 includes a wiper arm 31 formed in a substantially rod shape, and a base end side in the longitudinal direction of the wiper arm 31 is fixed to a pivot shaft 11 provided rotatably on the vehicle 10. A wiper blade 32 is attached to a tip side in the longitudinal direction of the wiper arm 31. Thus, by driving the wiper device 20, the wiper arm 31 swings on the windshield 12.

[0013] The wiper device 20 includes a wiper motor (motor with a speed reducer) 40. The wiper motor 40 includes an output shaft 41, and a link mechanism 42 is provided between the output shaft 41 and the pair of pivot shafts 11 to convert the rotational motion of the output shaft 41 into the swinging motion of the pair of pivot shafts 11. As a result, when the wiper motor 40 is operated, the rotational motion of the output shaft 41 becomes the swinging motion of the pivot shafts 11 via the link mechanism 42, and the wiper blades 32 perform a reciprocating wiping motion in each wiping range 13.

[0014] Here, the wiper motor 40 is attached to the vehicle 10 such that the output shaft 41 of the wiper motor 40 faces downward of the vehicle 10. That is, in the wiper motor 40, the gear case 70 side (see FIG. 2) from which the output shaft 41 protrudes faces downward of the vehicle 10, and the gear cover 80 side (see FIG. 2) that closes the gear case 70 faces upward of the vehicle 10.

[0015] As shown in Fig. 2, the wiper motor 40 forming the wiper device 20 includes a motor section 50 and a reduction mechanism section 60. The motor section 50 includes a yoke (motor case) 51 formed into a substantially cylindrical shape with a bottom by deep drawing a steel plate or the like, and a total of four magnets 52 (only two are shown in the figure) are fixed to the radially inner side of the yoke 51 as shown in Fig. 3. In addition, an armature core 53 is rotatably provided on the radially inner side of each magnet 52 via a predetermined gap (air gap).

[0016] An armature shaft (rotating shaft) 54 made of a round steel bar is fixed to the center of rotation of the armature core 53. The armature shaft 54 ​​rotates together with the rotation of the armature core 53. A pair of worms 55 are integrally provided on the tip side (left side in FIG. 3) of the armature shaft 54, and the twisting directions of the respective worms 55 are opposite to each other.

[0017] Furthermore, a commutator 56 is fixed between the worm 55 and the armature core 53 in the longitudinal direction of the armature shaft 54. A total of three brushes 57 (only two are shown in the figure) are in sliding contact with the outer periphery of the commutator 56. In this manner, the wiper motor 40 is an electric motor with brushes, and is driven to rotate in the forward or reverse direction by the supply of driving current from a battery (not shown) or the like installed in the engine room or the like.

[0018] As shown in Fig. 2, the reduction mechanism section 60 includes a gear case 70 and a gear cover 80. The gear case 70 and the gear cover 80 correspond to the housing in the present invention. As shown in Fig. 3, the reduction mechanism SD is housed inside the gear case 70 and the gear cover 80. The reduction mechanism SD is formed of a pair of worms 55 provided on the armature shaft 54, a pair of counter gears 61 meshed with the worms 55, respectively, and a single spur gear 62 meshed with the counter gears 61.

[0019] A pair of worms 55 are meshed with the large diameter tooth portions 61a of the pair of counter gears 61, respectively. As a result, the pair of counter gears 61 are rotated in the same direction (counterclockwise direction) as indicated by arrow R2 in conjunction with the rotation of the armature core 53 (see arrow R1). Furthermore, teeth 62a of the spur gear 62 are meshed with the small diameter tooth portions 61b of the pair of counter gears 61. As a result, the spur gear 62 is rotated in the clockwise direction as indicated by arrow R3.

[0020] As a result, the high-speed rotation of the armature core 53 (armature shaft 54) is decelerated by the pair of worms 55 and the pair of counter gears 61, causing the spur gear 62 to rotate at a low speed. As a result, a high-torque rotational force is output from the output shaft 41 fixed to the rotation center of the spur gear 62 toward the link mechanism 42 (see FIG. 1).

[0021] 2, the gear case 70 forming the reduction mechanism 60 is formed into a roughly bowl-like shape with a case bottom wall (not shown) by pouring molten aluminum material into a mold. The gear cover 80 forming the reduction mechanism 60 is formed into a roughly bowl-like shape with a cover bottom wall 81 by pouring molten plastic material into a mold (not shown).

[0022] When the gear case 70 and the gear cover 80 are butted against each other, a hollow portion 63 (see FIGS. 4 and 5) is formed therein, and the reduction gear mechanism SD (see FIG. 3) is housed inside the hollow portion 63. When the motor section 50 and the reduction gear mechanism section 60 are assembled, the inside of the hollow portion 63 and the inside of the yoke 51 (not shown) are in communication with each other.

[0023] In addition, the connection (butting portion) between the gear case 70 and the gear cover 80, and the connection (butting portion) between the gear case 70 and the yoke 51 are sealed with each other via a sealing member (not shown) such as an O-ring, thereby preventing rainwater and the like from entering the inside of the wiper motor 40 through these connection portions.

[0024] Here, a total of three mounting legs 72 (only two are shown in the figure) are integrally provided on the case bottom wall of the gear case 70, and the wiper motor 40 is fixed to the vehicle 10 via these mounting legs 72. In addition, the output shaft 41 fixed to the spur gear 62 is rotatably supported via a seal member (not shown) such as an O-ring at approximately the center of the case bottom wall. This prevents rainwater and the like from entering the inside of the wiper motor 40 from between the output shaft 41 (see FIG. 3) and the case bottom wall. Furthermore, the central shaft 61c (see FIG. 3) of the pair of counter gears 61 is also rotatably supported on the case bottom wall of the gear case 70.

[0025] As shown in Fig. 2, the gear cover 80 is fixed to the gear case 70 by a total of four fixing screws SC1. A connector connection portion 82 is integrally provided on the gear cover 80. An external connector (not shown) provided on the vehicle 10 is connected to a tip portion (left side in the figure) of the connector connection portion 82. This allows a drive current to be supplied to the wiper motor 40 from a battery or the like of the vehicle 10. Here, the external connector is connected to the connector connection portion 82 from the opposite side to the motor unit 50 side of the gear cover 80. In other words, the connector connection portion 82 is disposed approximately coaxially with the motor unit 50 as shown in Fig. 2.

[0026] 2 and 4, a breathing mechanism 90 is provided near the connector connection portion 82 in the gear cover 80. The breathing mechanism 90 includes a communication hole 91, a small diameter cylindrical portion 92, a cylindrical member 93, a filter 94, and a breather cap 95. The communication hole 91, the small diameter cylindrical portion 92, and the cylindrical member 93 are integrally provided in the gear cover 80 and are formed together when the gear cover 80 is molded. The breathing mechanism 90 has a function of providing the wiper motor 40 with a breathing function in order to suppress pressure fluctuations inside and outside the wiper motor 40.

[0027] Specifically, the breathing mechanism 90 has a function of allowing air to smoothly flow in and out (breathe) in response to pressure fluctuations inside and outside the wiper motor 40, while preventing rainwater, etc. from entering the inside of the wiper motor 40. Here, to obtain an ideal breathing mechanism 90, it is necessary to achieve both of the above-mentioned contradictory phenomena, that is, facilitating "breathing" and preventing rainwater, etc. from entering.

[0028] The breathing mechanism 90 is disposed in a portion of the gear cover 80 away from the motor unit 50 (see FIG. 2). As a result, even if rainwater or the like enters the inside of the wiper motor 40 via the breathing mechanism 90, the entered rainwater or the like is less likely to reach the commutator 56 or the brushes 57 (see FIG. 3). This effectively prevents the wiper motor 40 and a controller (not shown) that controls the wiper motor 40 from being damaged by an overcurrent.

[0029] 4 and 5, the communication hole 91 is provided in a cover flat portion 84 that is offset in the axial direction of the output shaft 41 (see FIG. 3) from the cover bottom wall 81 of the gear cover 80. Specifically, the communication hole 91 is provided in a portion of the gear cover 80 closer to the gear case 70 (lower portion in FIG. 4) in the axial direction of the output shaft 41. The inner diameter of the communication hole 91 is about 2 mm. The communication hole 91 communicates between the inside and outside of the gear cover 80 (wiper motor 40) and functions as a so-called "breathing hole."

[0030] The small diameter cylindrical portion 92 is provided outside the gear cover 80 and extends in the axial direction of the communication hole 91. An air passage 92a is provided inside the small diameter cylindrical portion 92, and the longitudinal base end side (lower side in FIG. 4) of the air passage 92a communicates with the communication hole 91. That is, the longitudinal base end side of the small diameter cylindrical portion 92 is integrally provided with the cover flat portion 84. The inner diameter dimension of the air passage 92a is about 2 mm, which is the same as the inner diameter dimension of the communication hole 91. The outer diameter dimension of the small diameter cylindrical portion 92 is about 5 mm. Furthermore, the height dimension H1 of the small diameter cylindrical portion 92 from the cover flat portion 84 is approximately 2 / 3 of the distance L from the cover flat portion 84 to the cover bottom wall 81 (H1 ≒ L × 2 / 3). The interior of the small diameter cylindrical portion 92 refers to the radially inner part of the small diameter cylindrical portion 92.

[0031] Moreover, the cylindrical member 93 is provided integrally with the cover flat surface portion 84 of the gear cover 80, and is disposed so as to surround the periphery of the small diameter cylindrical portion 92. That is, the cylindrical member 93 extends in the axial direction of the small diameter cylindrical portion 92 and the communication hole 91 (the axial direction of the output shaft 41). Specifically, the cylindrical member 93 is provided outside the gear cover 80, and the axial base end side of the cylindrical member 93 is fixed to the cover flat surface portion 84.

[0032] Here, the inner diameter dimension of the cylindrical member 93 is about 10 mm, and the inside of the cylindrical member 93 is communicated with the communication hole 91 through the air passage 92a of the small diameter cylindrical portion 92. As a result, the inside and outside of the wiper motor 40 are communicated with each other through the cylindrical member 93, the small diameter cylindrical portion 92, and the communication hole 91, and air flows through these cylindrical member 93, the small diameter cylindrical portion 92, and the communication hole 91. In other words, a small diameter cylindrical portion 92 having a smaller diameter than the cylindrical member 93 is provided inside the cylindrical member 93, and an air passage 92a inside the small diameter cylindrical portion 92 is communicated with both the inside of the cylindrical member 93 and the communication hole 91. The inside and outside of the cylindrical member 93 refer to the radially inner and outer parts of the cylindrical member 93.

[0033] The height dimension H2 of the cylindrical member 93 from the cover flat portion 84 is approximately equal to the distance L from the cover flat portion 84 to the cover bottom wall 81 (H2≈L). This prevents the cylindrical member 93 (breathing mechanism 90) from significantly protruding in the axial direction of the communication hole 91, thereby preventing the wiper motor 40 from becoming larger. In other words, the breathing mechanism 90 is disposed in a relatively large dead space DS (see FIGS. 2 and 5) formed in the gear cover 80.

[0034] In this way, by providing a small diameter cylindrical portion 92 and a cylindrical member 93 that communicate with the communication hole 91, when the wiper motor 40 becomes wet, rainwater, etc. that runs down the surface of the wiper motor 40 is less likely to reach the hollow portion 63 inside the wiper motor 40.

[0035] As shown in Figs. 4 and 5, the cylindrical member 93 is provided with a pair of slits 93a, 93b. These slits 93a, 93b extend in the axial direction of the cylindrical member 93 and are provided over the entire longitudinal area of ​​the cylindrical member 93. The pair of slits 93a, 93b penetrate the cylindrical member 93 in the radial direction to communicate the inside and outside of the cylindrical member 93. The pair of slits 93a, 93b are arranged at approximately 90 degree intervals from each other in the circumferential direction of the cylindrical member 93. As a result, even if a breather cap 95 is attached to the axial tip side of the cylindrical member 93, air can circulate between the inside and outside of the cylindrical member 93 via the pair of slits 93a, 93b.

[0036] 5, one slit 93a is disposed on the side farther from the hollow portion 63, and the other slit 93b is disposed on the side closer to the hollow portion 63. In addition, in the mounting posture of the wiper motor 40 on the vehicle 10, one slit 93a is disposed toward the lower side of the vehicle 10, and the other slit 93b is disposed toward the upper side of the vehicle 10 (see FIG. 7).

[0037] An opening width W1 of one slit 93a on the inner side of the cylindrical member 93 is wider than an opening width W2 on the outer side (W1>W2). In other words, the opening width of one slit 93a in the circumferential direction of the cylindrical member 93 is narrower on the outer side (opening width W2) than on the inner side (opening width W1) of the cylindrical member 93. Here, the opening width W1 is about 2.5 mm, and the opening width W2 is about 1.5 mm.

[0038] This makes it difficult for rainwater, etc. to enter the inside of the cylindrical member 93 through one of the slits 93a. Even if rainwater, etc. does enter the inside of the cylindrical member 93, the amount is very small, and the rainwater, etc. tends to collect inside one of the slits 93a with the opening width W1. Therefore, rainwater, etc. that has entered the inside of the cylindrical member 93 through one of the slits 93a can be quickly discharged to the outside of the cylindrical member 93.

[0039] In addition, in the other slit 93b, the opening width W3 on the inner side of the cylindrical member 93 is also wider than the opening width W4 on the outer side (W3>W4). In other words, the opening width of the other slit 93b in the circumferential direction of the cylindrical member 93 is narrower on the outer side (opening width W4) than on the inner side (opening width W3) of the cylindrical member 93. Here, the opening width W3 is about 2.5 mm, and the opening width W4 is about 1.5 mm.

[0040] 5 and 6, a pair of rib members 93c are provided on the outer circumferential surface of the cylindrical member 93 at intervals of approximately 90 degrees in the circumferential direction of the cylindrical member 93. These rib members 93c have approximately the same thickness as the cylindrical member 93, protrude outside the cylindrical member 93, and extend in the axial direction of the cylindrical member 93.

[0041] Here, the base end side of the rib member 93c in the axial direction of the cylindrical member 93 is fixed to the cover flat portion 84. A tapered portion TP is provided on the tip side of the rib member 93c in the axial direction of the cylindrical member 93, and the tapered portion TP is formed so that the height dimension of the rib member 93c in the radial direction of the cylindrical member 93 gradually decreases toward the tip side of the rib member 93c. This makes it possible to easily release the mold used when injection molding the gear cover 80.

[0042] The pair of slits 93a, 93b and the pair of rib members 93c are arranged at positions alternately shifted by approximately 45 degrees in the circumferential direction of the cylindrical member 93. More specifically, as shown in Fig. 5, when the cylindrical member 93 is viewed from the axial direction, the other slit 93b, the rib member 93c, the one slit 93a, and the rib member 93c are arranged in this order from the left in the drawing in the circumferential direction of the cylindrical member 93.

[0043] Here, the pair of rib members 93c are disposed on both sides of one of the slits 93a in the circumferential direction of the cylindrical member 93. This makes it possible to direct rainwater, etc., running down the surface of the wiper motor 40 away from one of the slits 93a when the wiper motor 40 is in an attached position to the vehicle 10 (see FIG. 7). In other words, the pair of rib members 93c has a function of preventing rainwater, etc., from entering the inside of the cylindrical member 93 through one of the slits 93a.

[0044] As shown in Fig. 4 and Fig. 6, the filter 94 is formed in a thin disk shape and is fixed to the longitudinal tip side (upper side in Fig. 4) of the small diameter cylindrical portion 92 by adhesive, welding, or the like. Specifically, the filter 94 is provided so as to block the air passage 92a of the small diameter cylindrical portion 92. The filter 94 is made of, for example, a porous film made of polytetrafluoroethylene (PTFE) and has the property of allowing air to pass through while blocking water, dust, and the like. This improves the water-resistant reliability of the wiper motor 40. However, the filter 94 can be omitted depending on the water-resistant performance required for the wiper motor 40.

[0045] As shown in Figs. 4 and 6, the breather cap 95 is made of an elastic material such as natural rubber and is formed in a substantially bowl shape. The breather cap 95 corresponds to the cap member of the present invention and includes a cap body 95a formed in a substantially disk shape and a fitting cylinder portion 95b that is fitted to the axial tip side of the cylindrical member 93. A plurality of annular protrusions 95c are integrally provided on the outer circumferential surface of the fitting cylinder portion 95b, and these annular protrusions 95c are fitted to the inner circumferential surface of the cylindrical member 93 while being elastically deformed. The outer circumferential surface of the fitting cylinder portion 95b refers to the radially outer portion of the fitting cylinder portion 95b.

[0046] As a result, the breather cap 95 closes the axial tip side of the cylindrical member 93 and is prevented from coming off the cylindrical member 93. However, it is also possible to omit the breather cap 95 depending on the mounting posture of the wiper motor 40. Specifically, when the output shaft 41 (see FIG. 3) of the wiper motor 40 faces upward on the vehicle 10, that is, when the breathing mechanism 90 of the gear cover 80 faces downward, the breather cap 95 can be omitted.

[0047] Here, with the breather cap 95 attached to the cylindrical member 93, the height dimension h from the cover flat portion 84 of the gear cover 80 to the tip portion of the fitting cylindrical portion 95b is approximately equal to the height dimension H1 from the cover flat portion 84 of the small diameter cylindrical portion 92 (h ≈ H1). This prevents the fitting cylindrical portion 95b from becoming too long in the axial direction, and makes it possible to easily attach the breather cap 95 to the cylindrical member 93 while suppressing elastic deformation of the breather cap 95.

[0048] Next, the breathing function and the function when the wiper motor 40 is wetted will be described in detail with reference to Fig. 7. In Fig. 7, the filter 94 and the breather cap 95 are omitted in order to make it easier to understand the path of the rainwater WA.

[0049] First, the respiratory function of the wiper motor 40 will be described.

[0050] When the wiper motor 40 installed in the engine room is operated, the internal temperature of the wiper motor 40 rises due to the heat generated by the wiper motor 40 and the high temperature atmosphere in the engine room. If the wiper motor 40 is splashed with rainwater WA in this state and the wiper motor 40 is wetted, the wiper motor 40 is rapidly cooled. Thus, a temperature difference occurs between the inside and outside of the wiper motor 40. Then, the temperature of the hollow portion 63 (see Figs. 4 and 5) of the wiper motor 40 becomes relatively low compared to the outside of the wiper motor 40. As a result, the hollow portion 63 becomes negative pressure, and the air outside the gear case 70 flows into the hollow portion 63 through the pair of slits 93a, 93b, the air passage 92a, and the communication hole 91. This suppresses the generation of a pressure difference between the inside and outside of the wiper motor 40.

[0051] On the other hand, when the internal temperature of the wiper motor 40 rises significantly by operating the wiper motor 40 at high speed for a long period of time, and the internal temperature of the wiper motor 40 exceeds the external temperature, the hollow portion 63 becomes hotter than the outside of the wiper motor 40. Then, contrary to the above, the hollow portion 63 becomes positive pressure, and the air inside the hollow portion 63 is discharged to the outside through the communication hole 91, the air passage 92a, and the pair of slits 93a, 93b. This suppresses the generation of a pressure difference between the inside and outside of the wiper motor 40.

[0052] However, the inside and outside of the wiper motor 40 are always in communication with each other via the pair of slits 93a, 93b, the air passage 92a, and the communication hole 91. Therefore, air does not suddenly move between the inside and outside of the wiper motor 40. Therefore, even if the filter 94 is provided, the wiper motor 40 can fully exhibit its breathing function.

[0053] Next, the function of the wiper motor 40 when it is wet will be described.

[0054] When the vehicle 10 runs in heavy rain, rainwater WA enters the engine compartment and wets the wiper motor 40. Then, as shown by arrow M1, the rainwater WA flows along the surface of the gear cover 80 toward the breathing mechanism 90. After that, the rainwater WA that reaches the breathing mechanism 90 flows in two directions with the cylindrical member 93 as a boundary, as shown by arrows M2 and M3, and the rainwater WA flowing along arrow M2 reaches the other slit 93b.

[0055] In contrast, rainwater WA flowing along arrow M3 reaches one rib member 93c (on the right side in the figure), and then flows down from one rib member 93c to the bottom of the vehicle 10 as shown by arrow M4. Therefore, rainwater WA flowing along arrows M3 and M4 flows down to the bottom of the vehicle 10 at a position away from one slit 93a.

[0056] Most of the rainwater WA that reaches the other slit 93b as shown by arrow M2 passes over the other slit 93b and flows along arrow M5. Then, it reaches the other rib member 93c (left side in the figure). After that, the rainwater WA that reaches the other rib member 93c flows down from the other rib member 93c to the bottom of the vehicle 10 as shown by arrow M6. As a result, the rainwater WA flowing along arrows M2, M5, and M6 flows down to the bottom of the vehicle 10 at a position away from one of the slits 93a.

[0057] Note that, as shown by arrow M7 (dashed line), a portion of the rainwater WA that reaches the other slit 93b may enter the interior of the cylindrical member 93 from the other slit 93b. The rainwater WA that has entered the interior of the cylindrical member 93 flows along the inner circumferential surface of the cylindrical member 93 and is smoothly collected in one of the slits 93a. Thereafter, as shown by arrow M8 (dashed line), the rainwater WA that has flowed along the inner circumferential surface of the cylindrical member 93 flows down from one of the slits 93a to the bottom of the vehicle 10.

[0058] This makes it difficult for rainwater WA to reach the small diameter cylindrical portion 92 and the air passage 92a, and thus the intrusion of rainwater and the like into the inside of the wiper motor 40 (hollow portion 63) is suppressed.

[0059] As described above in detail, according to the wiper motor 40 of the present embodiment, the cylindrical member 93 is provided with a pair of slits 93a, 93b extending in the axial direction of the cylindrical member 93, and the opening width of the pair of slits 93a, 93b in the circumferential direction of the cylindrical member 93 is narrower on the outer side (opening widths W2, W4) than on the inner side (opening widths W1, W3) of the cylindrical member 93. This prevents rainwater, etc. from reaching the communication hole 91 inside the cylindrical member 93, and allows rainwater, etc. that has entered the inside of the cylindrical member 93 to be quickly discharged to the outside of the cylindrical member 93. Therefore, the intrusion of rainwater, etc. into the inside (hollow portion 63) of the gear cover 80 is effectively prevented, and water exposure reliability can be improved.

[0060] Moreover, according to the wiper motor 40 of this embodiment, a small diameter cylindrical portion 92 having a smaller diameter than the cylindrical member 93 is provided inside the cylindrical member 93, and an air passage 92a inside the small diameter cylindrical portion 92 communicates with the inside of the cylindrical member 93 and the communication hole 91. This makes it possible to make the passage through which the air passes inside the cylindrical member 93 complex like a maze. This makes it possible to more reliably prevent rainwater, etc. from entering the inside of the gear cover 80 (hollow portion 63), and further improve the water exposure reliability.

[0061] Furthermore, in the wiper motor 40 according to this embodiment, the axial tip side of the cylindrical member 93 is closed by a breather cap 95. This makes it possible to more reliably prevent rainwater and the like from entering the hollow portion 63 when the wiper motor 40 is attached to the vehicle 10 in a position in which the gear case 70 side faces downward of the vehicle 10 and the gear cover 80 side faces upward of the vehicle 10 (see FIG. 2).

[0062] Furthermore, according to the wiper motor 40 of this embodiment, a rib member 93c extending in the axial direction of the cylindrical member 93 is provided on the outer peripheral surface of the cylindrical member 93, and a pair of slits 93a, 93b and a pair of rib members 93c are alternately arranged in the circumferential direction of the cylindrical member 93. This allows rainwater WA running down the surface of the wiper motor 40 to flow down the rib member 93c, and thus makes it possible to keep the rainwater WA away from one of the slits 93a. This further improves the water exposure reliability.

[0063] Furthermore, the wiper motor 40 according to the present embodiment can improve the water-wet reliability to extend the product's lifespan and ultimately reduce the energy required for production. This contributes to the Sustainable Development Goals (SDGs) led by the United Nations, particularly to Goal 7 (Ensure access to affordable, reliable, sustainable and modern energy) and Goal 13 (Take urgent action to combat climate change and its impacts).

[0064] Next, a second embodiment of the present invention will be described in detail with reference to the drawings. Note that parts having the same functions as those in the first embodiment are given the same reference numerals, and detailed descriptions thereof will be omitted.

[0065] FIG. 8 shows a cross-sectional view of the periphery of a cylindrical member in a wiper motor according to the second embodiment.

[0066] 8, the wiper motor (motor with a speed reduction mechanism) 100 of the second embodiment is different from the wiper motor 40 of the first embodiment (see FIG. 4) only in the height dimension H3 of the small diameter cylindrical portion 110 (air passage 110a) from the cover flat portion 84. Specifically, the height dimension H3 of the small diameter cylindrical portion 110 (air passage 110a) is set so that the axial tip side of the small diameter cylindrical portion 110 (air passage 110a) enters inside the fitting cylindrical portion 95b of the breather cap 95.

[0067] That is, in a state where the breather cap 95 is attached to the cylindrical member 93, the height dimension h from the cover flat portion 84 of the gear cover 80 to the tip portion of the fitting cylinder portion 95b is smaller than the height dimension H3 from the cover flat portion 84 of the small-diameter cylinder portion 110 (air passage 110a) (h < H3). Thereby, while making the passage through which the air inside the cylindrical member 93 passes into a maze shape, it can be made longer than in the first embodiment.

[0068] Also in the second embodiment formed as described above, substantially the same operational effects as those of the first embodiment described above can be achieved. In addition to this, in the second embodiment, since the axial tip side of the small-diameter cylinder portion 110 (air passage 110a) enters the inside of the fitting cylinder portion 95b of the breather cap 95, while making the passage through which the air inside the cylindrical member 93 passes into a maze shape, it can be made longer than in the first embodiment. Therefore, it is possible to more reliably prevent rainwater or the like from entering the inside (hollow portion 63) of the gear cover 80 and further improve the water immersion reliability.

[0069] Next, a third embodiment of the present invention will be described in detail with reference to the drawings. Note that parts having the same functions as those in the first embodiment described above are denoted by the same reference numerals, and detailed descriptions thereof are omitted.

[0070] FIG. 9 shows a plan view of the wiper motor according to the third embodiment, FIG. 10 shows an exploded perspective view showing the internal structure of the wiper motor of FIG. 9, and FIG. 11 shows a cross-sectional view around the cylindrical member along the line C-C of FIG. 10.

[0071] As shown in FIG. 9, the third embodiment is different from the first embodiment in that a wiper motor 120 having a brushless motor 121 is adopted. Also, as shown in FIG. 10, a total of three slits 131 are provided in a cylindrical member 130 forming the breathing mechanism 90, and a rib member is omitted. Furthermore, a fitting structure of a breather cap (cap member) 140 forming the breathing mechanism 90 to the cylindrical member 130 is different. Also, as shown in FIG. 11, the breathing mechanism 90 of the third embodiment has a shorter axial dimension than the breathing mechanism 90 of the first embodiment (see FIG. 4). Here, the slit 131 has the same shape as the slit 93a of the first embodiment (see FIG. 5), and the opening width of the slit 131 in the circumferential direction of the cylindrical member 130 is narrower on the outer side than on the inner side of the cylindrical member 130.

[0072] Specifically, wiper motor (motor with speed reduction mechanism) 120 includes a case (housing) 123 that houses motor 121 and speed reduction mechanism 122, a cover member (housing) 124 that seals a first opening (not shown) of case 123, and a motor cover 125 that closes a second opening (not shown) of case 123. The case 123, cover member 124, and motor cover 125 form the outer shell of wiper motor 120 when assembled together.

[0073] Motor 121 housed in case 123 includes stator 121a. Stator 121a is formed into a generally cylindrical shape by laminating a plurality of steel plates, which are magnetic bodies, and U-phase, V-phase, and W-phase coils (not shown) are wound in a predetermined manner around a plurality of radially inner teeth (not shown).

[0074] The rotor 121b is rotatably accommodated in the radially inner side of the stator 121a with a predetermined gap therebetween. The rotor 121b is formed in a substantially cylindrical shape by laminating a plurality of steel plates, which are magnetic bodies. The rotor 121b is provided with a plurality of permanent magnets (not shown).

[0075] Furthermore, the base end side (lower side in FIG. 9) of the rotating shaft 121c is fixed to the center of rotation of the rotor 121b. A worm 122a formed by rolling or the like is integrally provided on the tip end side (upper side in FIG. 9) of the rotating shaft 121c. Here, the worm 122a constitutes the reduction mechanism 122 together with a worm wheel 122b housed in a case 123.

[0076] A base end of the output shaft 41 is fixed to the center of rotation of the worm wheel 122b, and a tip end of the output shaft 41 protrudes to the outside of the case 123. A link mechanism 42 (see FIG. 1) is attached to the output shaft 41, as in the first embodiment.

[0077] As shown in Fig. 10, the cover member 124 is made of plastic and includes a cover bottom wall 124a. A connector connection portion 124b to which an external connector (not shown) provided on the vehicle 10 is connected is integrally formed. A control board 126 for controlling the wiper motor 120 is attached inside the cover member 124. A plurality of electronic components EP are mounted on the front and back sides of the control board 126. This causes the motor 121 (see Fig. 9) to rotate in a predetermined direction at a predetermined rotation speed.

[0078] Furthermore, a plastic board cover 127 is attached to the control board 126. That is, the control board 126 is disposed between the cover member 124 and the board cover 127 inside the case 123 (see FIG. 9). Here, the board cover 127 prevents the lubricating grease (not shown) applied to the speed reduction mechanism 122 (worm 122a and worm wheel 122b) from scattering and adhering to the control board 126.

[0079] 10, the breathing mechanism 90 is disposed in a dead space DS outside the cover bottom wall 124a of the cover member 124 and near the connector connection portion 124b. As shown in Fig. 11, the breather cap 140 includes a cap body 141 and a fitting cylinder portion 142. A single annular protrusion 142a is integrally provided on the inner circumferential surface of the fitting cylinder portion 142, and the annular protrusion 142a is fitted to the outer circumferential surface of the cylindrical member 130 while elastically deforming.

[0080] The third embodiment formed as above can also achieve substantially the same effects as the first embodiment. In addition, in the third embodiment, the motor 121 is a brushless motor, the speed reduction mechanism 122 is formed only of the worm 122a and the worm wheel 122b, and the structure of the breathing mechanism 90 is simplified while the axial length is shortened, so that the number of parts of the wiper motor 120 can be reduced compared to the first embodiment. This not only reduces the manufacturing cost, but also makes it possible to achieve a smaller and lighter motor.

[0081] The present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made without departing from the gist of the present invention. For example, in the above-described embodiments, the breathing mechanism 90 is provided on the gear cover 80 and the cover member 124, respectively, but the present invention is not limited to this. For example, in the case of an installation posture in which the gear case 70 side faces downward with respect to the vehicle 10, the breathing mechanism may be provided on the gear case 70 and the case 123.

[0082] In addition, in each of the above-described embodiments, the wiper motors 40, 100, 120 are applied to a front wiper device that wipes the wiping area 13 on the windshield 12, but the present invention is not limited to this and can also be applied to a rear wiper device that wipes a wiping area on the rear windshield.

[0083] Furthermore, in each of the above-described embodiments, the wiper motors 40, 100, 120 have been used as examples, but the present invention is not limited to this, and can also be applied to motors with reduction mechanisms for other applications that have a similar mounting position and may be exposed to water.

[0084] In addition, the material, shape, size, number, installation location, etc. of each component in each of the above-mentioned embodiments are arbitrary as long as the present invention can be achieved, and are not limited to the above-mentioned embodiments. [Explanation of symbols]

[0085] 10: vehicle, 11: pivot shaft, 12: windshield, 13: wiping range, 20: wiper device, 30: wiper member, 31: wiper arm, 32: wiper blade, 40: wiper motor (motor with reduction mechanism), 41: output shaft, 42: link mechanism, 50: motor section, 51: yoke, 52: magnet, 53: armature core, 54: armature shaft (rotating shaft), 55: worm, 56: commutator, 57: brush, 60: reducer Structural part, 61: counter gear, 61a: large diameter tooth part, 61b: small diameter tooth part, 61c: central shaft, 62: spur gear, 62a: tooth part, 63: hollow part, 70: gear case (housing), 72: mounting leg, 80: gear cover (housing), 81: cover bottom wall, 82: connector connection part, 84: cover flat part, 90: breathing mechanism, 91: communication hole, 92: small diameter cylindrical part, 92a: air passage, 93: cylindrical member, 93a, 93b: slit, 93c: rib member , 94: filter, 95: breather cap (cap member), 95a: cap body, 95b: fitting cylinder portion, 95c: annular protrusion portion, 100: wiper motor (motor with reduction mechanism), 110: small diameter cylinder portion, 110a: air passage, 120: wiper motor (motor with reduction mechanism), 121: motor, 121a: stator, 121b: rotor, 121c: rotating shaft, 122: reduction mechanism, 122a: worm, 122b: worm wheel, 123 : Case (housing), 124: Cover member (housing), 124a: Cover bottom wall, 124b: Connector connection part, 125: Motor cover, 126: Control board, 127: Board cover, 130: Cylindrical member, 131: Slit, 140: Breather cap (cap member), 141: Cap body, 142: Fitting cylinder part, 142a: Annular protrusion, DS: Dead space, EP: Electronic part, SD: Reduction mechanism, TP: Tapered part, WA: Rainwater

Claims

1. A motor unit having a rotating shaft; a speed reduction mechanism unit having a speed reduction mechanism for reducing the rotation speed of the rotating shaft; A motor with a reduction mechanism comprising: a housing that accommodates the reduction mechanism; a communication hole provided in the housing for communicating between the inside and the outside of the housing; a cylindrical member that is formed by a member provided outside the housing and the housing, extends in the axial direction of the communication hole, and has an interior that communicates with the communication hole; A slit is provided in the cylindrical member and extends in an axial direction of the cylindrical member; having An opening width of the slit in the circumferential direction of the cylindrical member is narrower on the outer side than on the inner side of the cylindrical member. Motor with reduction mechanism.

2. 2. The motor with a reduction mechanism according to claim 1, a small-diameter cylindrical portion having a diameter smaller than that of the cylindrical member is provided inside the cylindrical member, and an inside of the small-diameter cylindrical portion is in communication with an inside of the cylindrical member and the communication hole, Motor with reduction mechanism.

3. 3. The motor with a reduction mechanism according to claim 2, The axial tip side of the cylindrical member is closed by a cap member. Motor with reduction mechanism.

4. 4. The motor with a reduction mechanism according to claim 3, The cap member is provided with a fitting cylindrical portion to be fitted into the cylindrical member, and an axial tip side of the small diameter cylindrical portion is inserted into the fitting cylindrical portion. Motor with reduction mechanism.

5. The motor with a reduction mechanism according to any one of claims 1 to 4, The cylindrical member is provided on an outer peripheral surface thereof with a rib member extending in an axial direction of the cylindrical member. Motor with reduction mechanism.

6. The slits and the rib members are alternately arranged in the circumferential direction of the cylindrical member. The motor with a reduction mechanism according to claim 5.

7. A motor unit having a rotating shaft; a speed reduction mechanism unit having a speed reduction mechanism for reducing the rotation speed of the rotating shaft; A motor with a reduction mechanism comprising: a housing that accommodates the reduction mechanism; a communication hole provided in the housing for communicating between the inside and the outside of the housing; a cylindrical member provided outside the housing, extending in the axial direction of the communication hole, and having an interior that communicates with the communication hole; A slit is provided in the cylindrical member and extends in an axial direction of the cylindrical member; having An opening width of the slit in the circumferential direction of the cylindrical member is narrower on the outer side than on the inner side of the cylindrical member. Motor with reduction mechanism.

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