JP2004306840A - Electric door mirror device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric door mirror device capable of preventing or effectively suppressing generation of abnormal sound and transmission loss of rotational force caused by an engagement defective of a worm gear and a worm wheel due to reaction from the worm wheel, being miniaturized as the whole of the device, and being reduced in weight. <P>SOLUTION: In the second worm gear 118, an outside dimension is gradually reduced from both end sides of the axial direction toward a center side, and a cross sectional shape is formed into a curved recessed shape as if the cross sectional shape is opened with a prescribed curvature toward the rotation radial direction outside of the second worm gear 118. The second worm wheel 90 is curved as if the cross sectional shape when cut along the axial direction in an outer peripheral part is opened outward with more than the curvature of the cross sectional shape of the second worm gear 118. As a result, the reaction from the second worm wheel 90 according to rotational force from the second worm gear 118 is dispersed to a plurality of engaged parts, and force applied per unit contact area is reduced. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electric door mirror device capable of rotating a mirror between a retracted position and a deployed position by a driving force of a motor.
[0002]
[Prior art]
2. Description of the Related Art In recent years, a rearview mirror in a vehicle employs a door mirror provided near a door panel corresponding to a driver's seat or a passenger's seat.
[0003]
In addition, this type of door mirror has a mirror between a deployment position where the rear of the vehicle can be visually recognized from the driver's seat or the like and a storage position where the reflection surface of the mirror faces the inside in the vehicle width direction (that is, the indoor side). There is an electric door mirror device that rotates an attached visor or the like by a driving force of a motor or the like (for example, see Patent Document 1 below).
[0004]
This type of electric door mirror device includes a stand fixed to a vehicle body. A cylindrical shaft is formed on the stand. A frame of a motor actuator to which the above-mentioned visor and the like are mechanically connected is rotatably supported on the shaft so as to be rotatable within a predetermined range around an axis substantially in the vertical direction of the vehicle. Inside the frame, a ring-shaped final worm wheel is rotatably supported by a shaft. However, this final worm wheel is basically integrally connected to the shaft by a clutch mechanism.
[0005]
Further, a motor is housed in the frame. The output shaft of the motor is mechanically connected to the final worm wheel by a reduction mechanism consisting of a gear train such as spur gears and worm gears of external teeth housed inside the frame, and the driving force of the motor is reduced. Conveyed to the final worm wheel. As mentioned above, the final worm wheel is basically connected integrally to the shaft.
[0006]
For this reason, when receiving the rotational force of the worm gear meshing with the worm wheel, the worm wheel rotates the worm gear around its own axis (that is, around the shaft) by its reaction force. Thereby, the above-described speed reduction mechanism, motor, and eventually the frame are rotated, and further, the visor provided with the mirror is rotated.
[0007]
[Patent Document 1]
JP 2002-274266 A
[0008]
[Problems to be solved by the invention]
Here, FIG. 5 shows a state where a general worm wheel 300 and a worm gear 302 are meshed. As described above, in the general electric door mirror device, when the pressing force based on the rotational force of the worm gear 302 acts on the worm wheel 300, the pressing reaction force F from the worm wheel 300 based on the pressing force is applied to the frame as described above. Is the rotational force that rotates. However, of the pressing reaction force F, the component in the direction of the arrow F1 in FIG. 6 acts in a direction to separate the worm gear 302 from the worm wheel 300, thereby deteriorating the meshing state between the worm wheel 300 and the worm gear 302. This causes abnormal noise and transmission loss of torque.
[0009]
Further, the contact area between the teeth of the worm gear 302 and the teeth of the worm wheel 300 at the meshing portion between the worm gear 302 and the worm wheel 300 is, for example, smaller than the contact area of the meshing portion between other types of spur gears. . Therefore, when the worm gear 302 applies the rotational force to the worm wheel 300, and when the reaction force from the worm wheel 300 corresponding to the rotational force is applied to the worm gear 302, the teeth of the worm gear 302 The load, that is, the stress is concentrated on a very small part of the teeth of the worm wheel 300.
[0010]
As described above, since the stress is concentrated on a very small part of the teeth of the worm gear 302 and the worm wheel 300, the teeth of the worm gear 302 and the worm wheel 300 must have sufficient mechanical strength. A material having high mechanical strength such as a material has to be used, and the worm gear 302 and the worm wheel 300 have to be enlarged. For this reason, it was difficult to reduce the size and weight of the driving portion of the electric door mirror device.
[0011]
The present invention, in consideration of the above facts, can prevent or effectively suppress the generation of abnormal noise and the transmission loss of rotational force due to poor meshing between the worm gear and the worm wheel due to the reaction force from the worm wheel, and An object is to obtain an electric door mirror device capable of reducing the size and weight of the entire device.
[0012]
[Means for Solving the Problems]
The electric door mirror device according to the first aspect of the present invention is an electric door mirror device for turning a mirror main body between a retracted position and a deployed position by a driving force of a motor, wherein the mirror main body is axially centered from both ends in the axial direction. The outer dimension gradually decreases toward, and the cross-sectional shape is concave worm gear curved so as to open at a predetermined curvature outward in the rotational radial direction, and meshes with the worm gear, and in the axial direction at the outer peripheral portion. A worm wheel having a sectional shape when cut along the worm wheel, the worm wheel being curved so as to open outward with the predetermined curvature or more, and the worm gear applying a rotational force to the worm wheel to rotate the worm wheel. Or, the mirror body is turned by rotation of the worm gear around the worm wheel due to a reaction force corresponding to the rotation force. It is characterized in that.
[0013]
According to the electric door mirror device according to the first aspect of the present invention, when the motor is driven, the driving force of the motor, that is, the rotation force is directly or a rotation transmission means such as a gear or the like, and is constituted by such a rotation transmission means. The worm gear is indirectly transmitted to the worm gear through the speed reducing means, and the worm gear is rotated about its axis.
[0014]
The worm gear meshes with the worm wheel, and the worm gear applies a rotational force to the worm wheel.
[0015]
Here, when the worm wheel has a rotatable structure, the worm wheel receiving the rotational force of the worm gear rotates around its own axis, and the rotation of the worm wheel moves the mirror body from the retracted position to the deployed position. Or, it is swung from the deployed position to the storage position.
[0016]
On the other hand, in the case of a structure in which the rotation of the worm wheel is basically restricted, the worm wheel cannot rotate around its own axis even when receiving the rotational force of the worm gear. Accordingly, a reaction force from the worm wheel corresponding to the rotational force applied to the worm wheel by the worm gear causes the worm gear and, consequently, the above-described reduction means (rotation transmission means) and the motor to rotate around the worm wheel. The rotation of the worm gear around the worm wheel causes the mirror body to pivot from the storage position to the deployed position or from the deployed position to the stored position.
[0017]
By the way, as described above, the worm gear applies a rotational force to the worm wheel by meshing between the worm gear and the worm wheel. Here, the worm gear of the electric door mirror device according to the present invention gradually decreases in external dimensions from both axial ends to the center, and has a cross-section opening at a predetermined curvature outward in the rotation radius direction of the worm gear. It has a concave shape curved. Further, the worm wheel that meshes with the worm gear is curved so as to open outward with a curvature equal to or greater than the curvature (predetermined curvature) of the sectional shape of the worm gear when cut along the axial direction in the outer peripheral portion.
[0018]
The worm gear and the worm wheel having such a configuration are different from the normal mesh between the worm gear and the worm wheel. (The contact area between the teeth of the worm gear and the teeth of the worm wheel) is larger than the contact area of the normal meshing portion between the worm gear and the worm wheel.
[0019]
As a result, the rotational force applied to the worm wheel from the worm gear and the reaction force applied to the worm gear from the worm wheel in accordance with this rotational force are not concentrated unlike the normal worm gear and the worm wheel, and are concentrated on a plurality of meshing portions. It is dispersed and the force applied per unit contact area is reduced.
[0020]
As described above, since the rotational force and the reaction force are dispersed without being concentrated, the separation of the worm gear from the worm wheel caused by the concentration of the reaction force is effectively prevented or suppressed. For this reason, good meshing between the worm gear and the worm wheel can be maintained for a long period of time, generation of abnormal noise due to transmission loss of the rotating force and the reaction force and poor meshing between the worm wheel and the worm gear, and generation of the rotating force. Transmission loss can be effectively reduced or prevented.
[0021]
The fact that the rotational force and the reaction force are dispersed without being concentrated in this way means that the stress concentration on the worm gear teeth and the worm wheel teeth can be reduced. Therefore, it is possible to set the mechanical strength of the worm gear and the worm wheel to be relatively low, thereby making it possible, for example, to change the material of the worm gear and the worm wheel from metal to synthetic resin. Therefore, the manufacturing cost of the worm gear and the worm wheel can be reduced, and the size and weight can be reduced.
[0022]
As described above, since the size and weight of the worm gear and the worm wheel can be reduced, the size and weight of the entire electric door mirror device can be reduced.
[0023]
An electric door mirror device according to a second aspect of the present invention is the electric door mirror device according to the first aspect, wherein the driven gear is provided coaxially and integrally with the worm gear on the axial side of the worm gear. A driving gear that meshes with the driven gear on the side opposite to the worm wheel via the worm gear, and that rotates by directly or indirectly receiving the driving force of the motor, and the driven gear via the worm gear, The worm gear and the driven gear are rotatably supported on the opposite side, and the displacement of the shaft portion of the worm gear and the driven gear in the shaft support portion to the side opposite to the worm wheel via the worm gear is regulated. And a supporting shaft portion.
[0024]
In the electric door mirror device according to the second aspect of the present invention, when the driving gear rotates by the driving force of the motor, that is, the rotational force, the driven gear that meshes with the driving gear rotates. Since the driven gear is provided coaxially and integrally with the worm gear, when the driven gear rotates, the worm gear rotates integrally with the driven gear. The mirror body is turned from the retracted position to the deployed position or from the deployed position to the retracted position by the rotational force of the worm gear or the reaction force from the worm wheel corresponding to the rotational force.
[0025]
By the way, when the rotational force is transmitted from the driving gear to the worm wheel as described above, the rotational force applied by the driving gear to the driven gear also acts in a direction in which the driven gear is separated from the driven gear.
[0026]
On the other hand, a reaction force acts on the worm gear from the worm wheel, and this reaction force tends to separate the worm gear from the worm wheel.
[0027]
Here, in the electric door mirror device according to the present invention, the shafts of the worm gear and the driven gear are supported by the shaft support on the side opposite to the driven gear via the worm gear. The shaft support interferes with the shaft and restricts the shaft from being displaced to the opposite side from the worm wheel via the worm gear.
[0028]
Accordingly, a reaction force when the shaft portion presses the shaft support portion and a pressing force based on the rotational force applied by the driven gear to the driven gear act on both ends in the axial direction of the worm gear. Since the driving gear is provided on the opposite side of the worm wheel via the worm gear, the above-described pressing force and the reaction force from the shaft support portion are substantially in the same direction, and the worm gear is moved from the worm wheel based on the reaction force from the worm wheel. It acts to oppose the separating force.
[0029]
In this way, the force opposing the force for separating the worm gear from the worm wheel acts on both axial sides of the worm gear, so that separation of the worm gear from the worm wheel is prevented or effectively suppressed, and the worm gear and the worm wheel are separated from each other. Good engagement can be maintained more reliably.
[0030]
As described above, in the electric door mirror device according to the present invention, since the meshing between the worm wheel and the worm gear can be favorably maintained, generation of abnormal noise and transmission loss of torque due to poor meshing between the worm wheel and the worm gear can be reduced. It can be effectively reduced or prevented.
[0031]
According to a third aspect of the present invention, in the electric door mirror device according to the first or second aspect, the electric door mirror device is provided integrally with the drive shaft of the motor, and is provided at a position closer to the outer periphery of the drive shaft. A pair of engaging portions protruding outward in the radial direction of rotation of the drive shaft, and a through-hole into which the drive shaft is rotatably inserted are formed in an axial portion, and a pair of opposed portions around the axial center of the through-hole. And a drive gear in which the engagement portion faces the pair of engagement walls around the axis of the drive shaft in a state where the drive shaft is inserted into the insertion hole. And transmitting the rotation of the drive gear to the worm wheel.
[0032]
In the electric door mirror device according to the third aspect of the present invention, the drive shaft of the motor is rotatably inserted into an insertion hole formed in the drive gear. Therefore, basically, even if the drive shaft is simply rotated by the driving force of the motor, the rotation of the drive shaft is not transmitted to the drive gear.
[0033]
However, an engagement hole having a pair of engagement walls is formed in the drive gear, and an engagement portion integral with the drive shaft is housed inside the engagement hole. Therefore, when the engaging portion rotates together with the drive shaft and abuts on one of the pair of engagement walls along the rotational direction, and further when the drive shaft rotates in the same direction in this abutting state, the engaging portion is rotated. The engagement portion presses the pair of engagement walls provided in the hole in the rotation direction to rotate the drive gear.
[0034]
By transmitting the torque of the drive gear directly or indirectly to the worm wheel, the mirror body is turned from the retracted position to the deployed position or from the deployed position to the retracted position.
[0035]
By the way, in the electric door mirror device according to the present invention, as described above, the rotational force of the drive shaft (ie, the drive force of the motor) is transmitted to the drive gear by the engagement portion pressing the engagement wall, and the drive gear Rotates.
[0036]
To further describe this point, the motor is driven in a state where the engagement portion is in contact with one of the engagement walls (or at least a state where the engagement portion is separated from the other engagement wall toward the one of the engagement walls). Even if the shaft rotates and the engaging portion rotates toward the other engaging wall, only the drive shaft and the engaging portion rotate until the engaging portion comes into contact with the other engaging wall. become. In this idling state, since the driving force of the motor is not transmitted to the driving gear, the load acting on the driving shaft is extremely small.
[0037]
For this reason, even if the initial torque immediately after the start of the motor drive is set relatively small, the drive shaft can start rotating smoothly and reliably. In addition, as described above, immediately after the driving of the motor is started, only the driving shaft rotates, but after the engaging portion comes into contact with the engaging wall, the engaging portion presses the engaging wall with the driving force of the motor to drive the driving gear. To rotate.
[0038]
Here, the engaging portion idles together with the drive shaft until the engaging portion contacts the engaging wall as described above. The impact torque when the engaging portion comes into contact with the engaging wall due to the idling becomes larger than the impact torque of the structure in which the drive shaft and the drive gear are integrally connected in advance. Therefore, even if a motor having a small torque is used, the drive gear can be reliably rotated to transmit the rotation to the worm wheel.
[0039]
The drive gear according to the present invention described in claim 3 may be the worm gear according to the present invention described in claim 1 or the driving gear according to the present invention described in claim 2, or may be the worm gear or the driving gear according to the present invention. Other gears constituting the rotation transmission means and the reduction means on the motor side of the gear may be used.
[0040]
BEST MODE FOR CARRYING OUT THE INVENTION
<Configuration of the present embodiment>
FIG. 2 is a cross-sectional view illustrating a configuration of the driving unit 12 of the electric door mirror device 10 according to the embodiment of the present invention. As shown in FIG. 1, the drive unit 12 of the electric door mirror device 10 includes a substrate 16 including a stand 14 formed of a synthetic resin material. The board 16 is fixed to a stay (not shown), and is fixed to a door panel of a vehicle (not shown) via the stay.
[0041]
A hollow (that is, pipe-shaped) shaft 18 is erected from the stand 14 constituting the substrate 16 substantially upward of the vehicle. A base 20 formed of a synthetic resin material is disposed substantially above the stand 14 on the vehicle. The base 20 is formed in a substantially bottomed cylindrical shape with an opening at the upper end of the vehicle. A circular hole 24 through which the shaft 18 passes is formed in the bottom wall 22 of the base 20, and the base 20 is rotatable around the shaft 18.
[0042]
Inside the base 20, a second worm wheel 90 as a worm wheel constituting the speed reduction means or the driving force transmission mechanism 11 is rotatably supported by the shaft 18 coaxially with the shaft 18. The clutch disc 28 is arranged on the opposite side of the second worm wheel 90 via the bottom wall 22. The clutch disc 28 is formed with a hole through which the shaft 18 penetrates. Although the displacement along the axial direction of the shaft 18 is basically possible, the rotation around the shaft 18 is disabled.
[0043]
Further, a compression coil spring 30 is fitted on the shaft 18 on the side opposite to the second worm wheel 90 via the clutch disk 28, and the biasing force of the compression coil spring 30 causes the clutch disk 28 to move the second worm wheel. It is pressed against the wheel 90. The pressing force of the clutch disc 28 based on the urging force of the compression coil spring 30 presses the second worm wheel 90 against the bottom wall 22 of the base 20, and the force between the clutch disc 28 and the bottom wall 22 and the second worm wheel 90 is increased. The friction basically disables rotation of the second worm wheel 90 with respect to the bottom wall 22 and the shaft 18.
[0044]
On the other hand, a motor support board 36 is provided on the base 20 radially outward of the second worm wheel 90, and a motor 42 as a driving unit is mounted on the motor support board 36. The axial direction of the drive shaft 44 of the motor 42 is substantially the same as the axial direction of the shaft 18. The drive shaft 44 penetrates the motor support board 36 and is rotatably fitted into a bearing hole 92 formed in the bottom wall 22. It is supported.
[0045]
A first worm gear 94 as a driving gear and a driving gear is arranged between the motor support board 36 and the bottom wall 22. As shown in FIG. 3, the first worm gear 94 is formed in a substantially cylindrical shape, and spiral worm gear teeth are formed on an outer peripheral portion thereof. The inside of the first worm gear 94 is formed as an insertion hole 96, into which the drive shaft 44 of the motor 42 is loosely fitted.
[0046]
An engagement hole 98 is formed in the first worm gear 94 at one axial end (upper end) of the first worm gear 94. An upper end of the insertion hole 96 is opened at a bottom of the engagement hole 98. ing. As shown in FIGS. 3 and 4A, the engagement hole 98 has a large diameter portion 100. The large diameter portion 100 is a circular hole having a larger diameter than the insertion hole 96 and is formed coaxially with the insertion hole 96. A fan 102 is formed on one radially outer side of the large diameter portion 100 through the center of the large diameter portion 100, and is opposite to the fan 102 via the large diameter portion 100. Also, a fan-shaped portion 102 is formed.
[0047]
These fan-shaped portions 102 are formed in a fan shape whose essential part substantially coincides with the axis of the large-diameter portion 100 and the insertion hole 96. In addition, the diameter of the fan-shaped portion 102 from its axis to the arc-shaped portion of the fan is sufficiently larger than the radius of the large-diameter portion 100. It is located outside the worm gear 94.
[0048]
A pressing piece 104 as an engaging portion is accommodated in the engaging hole 98 formed by the fan-shaped portion 102 and the large-diameter portion 100. The pressing piece 104 has a substantially cylindrical base 106. The outer diameter of the base 106 is slightly smaller than the inner diameter of the large diameter portion 100, and when the pressing piece 104 is accommodated in the engagement hole 98, the base 106 is located inside the large diameter portion 100. And is rotatably fitted around the axis of the large diameter portion 100.
[0049]
The inner diameter of the base 106 is substantially equal to the outer diameter of the drive shaft 44 of the motor 42 (strictly, slightly smaller), and the base 106 is press-fitted to the base end side of the drive shaft 44 so that the base 106 and the drive shaft 44 are connected substantially integrally.
[0050]
On the other hand, a substantially rectangular parallelepiped rectangular piece 108 extends from the outer peripheral portion of the base 106. The rectangular pieces 108 are formed so as to extend in mutually opposite directions via the base 106 (that is, a pair of the rectangular pieces 108 is formed). The extension of the rectangular piece 108 from the outer periphery of the base 106 is slightly smaller than the length obtained by subtracting the radius of the large diameter portion 100 from the diameter of the fan 102 from the axis to the arc. When fitted into the large-diameter portion 100, one rectangular piece 108 is accommodated inside one fan-shaped portion 102, and the other rectangular piece 108 is accommodated in the other fan-shaped portion 102.
[0051]
The thickness dimension of the rectangular piece 108 (the length from one surface to the other surface of the rectangular piece 108 along the direction around the axis of the large-diameter portion 100) is one of the rectangular pieces 108 in the thickness direction. Is in contact with the engaging wall 102A, which is an inner peripheral surface corresponding to one side of one fan-shaped portion 102, and one surface in the thickness direction of the other rectangular piece 108 is connected to the other fan-shaped portion. It is set so as to come into contact with an engaging wall 102 </ b> A which is an inner peripheral surface corresponding to one side portion of 102.
[0052]
Accordingly, the base 106 rotates a predetermined angle (for example, about 60 degrees) inside the large-diameter portion 100 in a state where one surface in the thickness direction of the two rectangular pieces 108 is in contact with the inner peripheral surface of the fan-shaped portion 102. When the other surface in the thickness direction of one rectangular piece 108 comes into contact with the engaging wall 102B, which is the inner peripheral surface of the fan-shaped portion 102, the other surface in the thickness direction of the other rectangular piece 108 also It contacts the engaging wall 102B which is the inner peripheral surface.
[0053]
On the other hand, as shown in FIG. 2, the lower end side of the first worm gear 94 is housed in a gear housing 110 formed on the bottom wall 22. Further, as shown in FIG. 1, a first worm wheel 112 as a driven gear constituting the reduction gear or the driving force transmission mechanism 11 is disposed beside the first worm gear 94. A part of the first worm wheel 112 is housed in the gear housing 110 formed on the bottom wall 22. A cylindrical boss 114 is formed coaxially and integrally with the first worm wheel 112 at one end in the axial direction of the first worm wheel 112.
[0054]
A shaft support 116 is provided in the gear housing 110 corresponding to the boss 114. The shaft support 116 extends from the inner wall of the gear housing 110 so as to sandwich the boss 114 from outside in the radial direction of the boss 114, and the first worm wheel 112 is supported by the shaft support 116. Is rotatably supported at one axial end. Further, a worm gear housing portion 124 is formed on the bottom wall 22 on the opposite side of the first worm wheel 112 via the boss 114, and a second worm gear 118 as a worm gear is housed therein.
[0055]
The second worm gear 118 is provided such that the axis is located on an extension of the axis of the first worm wheel 112 and the boss 114. As shown in FIG. 5, the second worm gear 118 is formed such that the diameter at the center in the axial direction is shorter than the diameter at both ends in the axial direction. The outer surface of the second worm wheel 90 has a concave shape that is curved beyond the radius of curvature so as to open outward in the rotation radius direction of the second worm gear 118.
[0056]
The second worm gear 118 meshes with the second worm wheel 90, and the direction of the teeth of the second worm gear 118 meshing with the second worm wheel 90 (the direction from the root to the tip) is substantially the second worm wheel 90. (That is, the second worm gear 118 is a “drum-shaped worm” corresponding to the second worm wheel 90).
[0057]
As shown in FIG. 1, a shaft 120 coaxially and integrally extends from one axial end of the second worm gear 118 (the side opposite to the first worm wheel 112 via the second worm gear 118). . A shaft support 122 is formed in the worm gear housing 124 corresponding to the shaft 120. The shaft support 122 has a wall shape opposed to each other via the shaft 120, and rotatably supports the shaft 120 by interfering with the shaft 120 from outside in the radial direction of the shaft 120.
[0058]
Further, a shaft 126 extends coaxially and integrally from the other end in the axial direction of the second worm gear 118 (the side opposite to the shaft 120 via the second worm gear 118). The shaft 126 is press-fitted from the boss 114 to the first worm wheel 112 and integrally joined. Thus, the first worm wheel 112 and the second worm gear 118 are coaxially and integrally connected.
[0059]
A shaft support 128 is formed on the side of the second worm gear 118 of the shaft support 116 that supports the boss 114. Like the shaft support 122, the shaft support 128 has a wall shape opposed to each other via a shaft 126, and rotatably supports the shaft 126 by interfering with the shaft 120 from the radial outside of the shaft 126.
[0060]
On the other hand, as shown in FIG. 1, a cover 48 formed of a synthetic resin material is disposed on the opening end side of the peripheral wall 34. The cover 48 is configured to include the peripheral wall 50, and by fitting the peripheral wall 50 to the open end of the peripheral wall 34, the covering portion 52 formed on the opposite side of the peripheral wall 50 from the peripheral wall 34 becomes the second worm wheel 90 or the like. The various members and the motor 42 disposed inside the peripheral wall 34 are covered from substantially above the vehicle.
[0061]
Further, as shown in FIG. 2, a bracket 82 is formed on a part of the outer periphery of the peripheral wall 34 of the base 20, and a frame (not shown) in which a mirror body (reflecting mirror) having a reflecting surface is attached to the bracket 82. Are fixed directly or indirectly.
[0062]
<Operation and effect of the present embodiment>
In the electric door mirror device 10, the electric power is supplied to the motor 42, so that the drive shaft 44 rotates. Since the drive shaft 44 is only loosely inserted into the insertion hole 96, the drive shaft 44 rotates in the insertion hole 96. When the drive shaft 44 rotates, the drive shaft 44 is press-fitted, so that the pressing piece 104 integrated with the drive shaft 44 rotates in the engagement hole 98. When the pressing piece 104 rotates, as shown in FIG. 4A, the rectangular piece 108 which has been in contact with the engaging wall 102A of the fan-shaped portion 102 as shown in FIG. It moves away from the engaging wall 102A and toward the engaging wall 102B of the fan-shaped portion 102.
[0063]
When the drive shaft 44 rotates by a certain angle (for example, about 60 degrees) from this state, the rectangular piece 108 interferes with the engaging wall 102B as shown in FIG. 4C. Further, when the drive shaft 44 rotates from this state, as shown in FIG. 4D, the rectangular piece 108 presses the engagement wall 102B in the rotation direction of the drive shaft 44. Thus, the rotational force of the drive shaft 44, that is, the drive force of the motor 42 is transmitted to the first worm gear 94, and the first worm gear 94 rotates.
[0064]
That is, in the present electric door mirror device 10, even when the electric power is supplied to the motor 42 and the drive shaft 44 starts rotating as described above, the drive shaft 44 does not idle and does not rotate the first worm gear 94, The drive shaft 44 rotates the first worm gear 94 after the drive shaft 44 rotates by a predetermined angle and the rectangular piece 108 interferes with the engagement wall 102B of the fan-shaped portion 102. As a result, the load acting on the motor 42 immediately after the start of the driving of the motor 42 can be reduced, and the motor 42 can be reliably operated and the first worm gear 94 can be reliably rotated.
[0065]
Further, when the first worm gear 94 is rotated by the driving force of the motor 42 in this manner, this rotating force is transmitted to the second worm gear 118 via the first worm wheel 112, and rotates the second worm gear 118. The rotational force of the second worm gear 118 is transmitted to the second worm wheel 90 and attempts to rotate the second worm wheel 90 around the shaft 18.
[0066]
However, as described above, the pressing force of the clutch disc 28 based on the urging force of the compression coil spring 30 causes friction between the bottom wall 22 of the base 20 and the clutch disc 28 and the second worm wheel 90, This friction makes the second worm wheel 90 unrotatable.
[0067]
Therefore, the second worm gear 118 causes the second worm gear 118 to rotate around the second worm wheel 90 (that is, around the shaft 18) due to the reaction force from the second worm wheel 90 in accordance with the pressing force applied to the second worm wheel 90 by the second worm gear 118. , And the base 20 rotates around the shaft 18.
[0068]
The base 82 is fixed to the bracket 82 between a deployed position where the rear of the vehicle can be visually recognized by the mirror main body by the rotation of the base 20 and a storage position where the reflection surface of the mirror main body is substantially inward in the vehicle width direction (substantially the vehicle interior side). The not-shown frame rotates.
[0069]
By the way, as shown in FIG. 1, when the base 20 rotates around the shaft 18, the second worm gear 118 receives a reaction force from the second worm wheel 90. This reaction force can be divided into a component in the rotation circumferential direction of the second worm wheel 90 and a component outside in the rotation radial direction of the second worm wheel 90. The reaction force (external force) F1, which is one of the components, acts to separate the second worm gear 118 from the second worm wheel 90.
[0070]
Here, when the second worm gear 118 attempts to separate from the second worm wheel 90 due to such a reaction force F1, the shaft support portion 122 is formed on both sides of the second worm gear 118 in the axial direction from the side opposite to the direction of action of the reaction force F1. The reaction force F2 generated when the shafts 120 and 126 press the two shaft supports 122 and 128 is applied to the shafts 120 and 126, and is applied to the both shafts 120 and 126 from the both shaft supports 122 and 128.
[0071]
As described above, in the electric door mirror device 10, in response to the reaction force F 1 applied to the second worm gear 118, the biaxial support portions 122 apply a reaction force in the opposite direction to the reaction force F 1 on both axial sides of the second worm gear 118. By providing the shafts 120 and 126 with a balance, the second worm gear 118 and the shafts 120 and 126 can be effectively suppressed or prevented from tilting.
[0072]
As described above, since the inclination of the second worm gear 118 and the shafts 120 and 126 can be suppressed or prevented, the meshing between the second worm wheel 90 and the second worm gear 118 can be favorably maintained. It is possible to prevent or effectively reduce the generation of abnormal noise and the transmission loss of rotational force due to the decrease in the meshing property with the second worm gear 118.
[0073]
On the other hand, of the rotational force from the first worm gear 94, the external force F3, which is a component radially outward in the rotational direction, acts on the first worm wheel 112, and when the first worm wheel 112 is inclined, the boss 114 is displaced. The bearing portion 116 that supports the shaft interferes with the boss 114 from a direction opposite to the direction in which the external force F3 acts, and applies a reaction force F4 to the boss 114. Thereby, the inclination of the first worm wheel 112 is prevented or effectively suppressed.
[0074]
As described above, the inclination of the first worm wheel 112 is prevented or effectively suppressed, so that the inclination of the second worm gear 118 due to the external force F3 can be prevented or effectively suppressed. Therefore, this can also prevent or effectively reduce the generation of abnormal noise and the transmission loss of rotational force due to the reduction in the meshing property between the second worm wheel 90 and the second worm gear 118.
[0075]
Further, the second worm gear 118 gradually decreases in linear dimension from both ends in the axial direction toward the center in the axial direction, and has a concave cross-sectional shape that is greater than the radius of curvature of the outer peripheral portion of the second worm wheel 90. In addition, the teeth of the second worm gear 118 are substantially oriented toward the rotation center of the second worm wheel 90 in a state of being engaged with the second worm wheel 90.
[0076]
For this reason, the side surfaces of the teeth of the second worm gear 118 are in contact with the side surfaces of the teeth of the second worm wheel 90, instead of the corners between the tip and the side surfaces of the teeth of the second worm gear 118 in the meshing state. As described above, in the present embodiment, the teeth of the second worm gear 118 and the teeth of the second worm wheel 90 are brought into contact by the side faces of the teeth of the second worm wheel 90 contacting the side faces of the teeth of the second worm gear 118. The contact area with the second worm gear 118 is increased, and the reaction force F1 applied from the second worm wheel 90 to the second worm gear 118 is dispersed.
[0077]
This also effectively suppresses or prevents the inclination of the second worm gear 118 and the shaft 120, and as a result, the generation of abnormal noise due to the decrease in the meshing property between the second worm wheel 90 and the second worm gear 118, The transmission loss of rotational force can be prevented or effectively reduced.
[0078]
Further, as described above, since the reaction force F1 applied from the second worm wheel 90 to the second worm gear 118 is not concentrated on one tooth but is dispersed on many teeth, the second worm wheel 90 and the second Even if the mechanical strength of each tooth of the worm gear 118 is low, each tooth is not damaged by the reaction force F1.
[0079]
That is, in the electric door mirror device 10, the mechanical strength of each tooth of the second worm wheel 90 and the second worm gear 118 can be set relatively low. Thus, for example, the material can be changed from a metal material to a synthetic resin material, and the second worm wheel 90 and the second worm gear 118 can be reduced in size and weight.
[0080]
Since the second worm wheel 90 and the second worm gear 118 can be reduced in size and weight in this manner, the entire electric door mirror device 10 can be reduced in size and weight.
[0081]
In this embodiment, the shafts 120 and 126 are supported by the shaft supports 122 and 128. However, only the shaft 120 is supported by the shaft support 122 and the shaft supports 116 and 128 are not provided. Alternatively, the reaction force F2 of the shaft support 122 and the external force F3 from the first worm gear 94 may be used to oppose the reaction force F1.
[0082]
【The invention's effect】
As described above, according to the present invention, the meshing between the worm gear and the worm wheel can be favorably maintained, and the transmission loss of rotational force and the generation of abnormal noise due to poor meshing can be effectively prevented or reduced. In addition, since the load during transmission of rotational force and the transmission of reaction force corresponding to this rotational force is dispersed without being concentrated on a very small part of the teeth of the worm gear and worm wheel, the mechanical strength of the worm gear and worm wheel is reduced. It can be set relatively low, which makes it possible to reduce the size and weight of the worm gear and the worm wheel, and thus reduce the size and weight of the entire device.
[Brief description of the drawings]
FIG. 1 is a schematic plan view of a main part of a drive unit of an electric door mirror device according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view illustrating a configuration of a driving unit of the electric door mirror device according to the embodiment of the present invention.
FIG. 3 is an exploded perspective view of a drive shaft of a motor and a worm gear as a rotation transmitting member.
4A and 4B are plan views of a worm gear as a rotation transmitting member, wherein FIG. 4A is a state before the rotation of the drive shaft is started, FIG. 4B is a state immediately after the rotation of the drive shaft is started, and FIG. (D) shows a state in which the drive shaft has rotated beyond a predetermined angle.
FIG. 5 is a plan sectional view showing a meshing state between the worm gear and the worm wheel.
FIG. 6 is a diagram showing a reaction force received by a worm gear from a worm wheel.
[Explanation of symbols]
10 Electric door mirror device
42 motor
44 Drive shaft
90 2nd worm wheel (worm wheel)
94 1st worm gear (drive gear, driving gear)
96 insertion hole
98 Engagement hole
102A Engagement wall
102B Engagement wall
104 Pressing piece (engaging part)
112 1st worm wheel (driven gear)
116 Shaft support
118 2nd worm gear (worm gear)
122 shaft support

Claims (3)

An electric door mirror device for turning a mirror body between a retracted position and a deployed position by a driving force of a motor,
A concave worm gear whose outer dimensions gradually decrease from the axial ends to the axial center, and whose cross-sectional shape is curved so as to open at a predetermined curvature outward in the radial direction of rotation;
A worm wheel that meshes with the worm gear and has a cross-sectional shape when cut along the axial direction in the outer peripheral portion and is curved so as to open outward with the predetermined curvature or more,
Wherein the worm gear rotates the mirror body by rotation of the worm wheel by applying a rotational force to the worm wheel or by rotation of the worm gear around the worm wheel by a reaction force corresponding to the rotational force.
An electric door mirror device characterized by the above-mentioned. A driven gear provided coaxially and integrally with the worm gear on the axial side of the worm gear;
A driving gear that meshes with the driven gear on the side opposite to the worm wheel through the worm gear, and that rotates by directly or indirectly receiving the driving force of the motor,
The worm gear and the driven gear are rotatably supported on the opposite side to the driven gear via the worm gear, and the worm is provided via the worm gear at the shaft portion of the worm gear and the driven gear at the shaft support portion. A shaft support that regulates displacement to the side opposite to the wheel,
The electric door mirror device according to claim 1, further comprising: An engagement portion that is provided integrally with the drive shaft of the motor, and that protrudes outward in the rotation radius direction of the drive shaft from an outer peripheral portion of the drive shaft;
An insertion hole into which the drive shaft is rotatably inserted is formed in an axis portion, and an engagement hole having a pair of engagement walls facing around the axis of the insertion hole is formed. A drive gear in which the engagement portion faces the pair of engagement walls around the axis of the drive shaft when the drive shaft is inserted.
Transmitting the rotation of the drive gear to the worm wheel,
The electric door mirror device according to claim 1 or 2, wherein:

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