JP4279036B2 - Electric door mirror device - Google Patents

Description

[0001]
BACKGROUND 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]
As a rear view mirror in a vehicle in recent years, a door mirror provided near a door panel corresponding to a driver seat or a passenger seat is employed.
[0003]
In addition, this type of door mirror has a mirror between a deployment position where the rear of the vehicle can be viewed with a mirror from a driver's seat and the like, and a storage position where the reflecting surface of the mirror faces the vehicle width direction inner side (that is, the indoor side). There is an electric door mirror device that rotates an attached visor or the like with a driving force such as a motor (see Patent Document 1 below as an example).
[0004]
This type of electric door mirror device includes a stand fixed to the vehicle body. A cylindrical shaft is formed on the stand. On the shaft, a frame of a motor actuator to which the above-described visor or the like is mechanically connected is supported so as to be rotatable within a predetermined range about an axis whose axial direction is substantially the vehicle vertical direction. Inside the frame, a final worm wheel formed in a ring shape is rotatably supported on a shaft. However, this final worm wheel is basically connected to the shaft integrally by a clutch mechanism.
[0005]
A motor is accommodated in the frame. The output shaft of the motor is mechanically connected to the final worm wheel by a speed reduction mechanism comprising a gear train such as an external spur gear or worm gear housed in the frame, and the driving force of the motor is being reduced. It is conveyed to the final worm wheel. As described above, the final worm wheel is basically integrally connected 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 the reaction force. As a result, the speed reduction mechanism, the motor, and thus the frame rotate, and the visor provided with the mirror rotates.
[0007]
[Patent Document 1]
JP 2002-274266 A
[0008]
[Problems to be solved by the invention]
Here, FIG. 5 shows a state in which a general worm wheel 300 and a worm gear 302 are engaged with each other. As described above, in a general electric door mirror device, when a 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. This is the rotational force that rotates the. However, the component in the direction indicated by the arrow F1 in FIG. 6 in the pressing reaction force F acts in a direction in which the worm gear 302 is separated from the worm wheel 300, and thereby the meshing state between the worm wheel 300 and the worm gear 302 is deteriorated. This causes generation of abnormal noise and transmission loss of rotational force.
[0009]
Further, the contact area between the teeth of the worm gear 302 and the teeth of the worm wheel 300 in the meshing portion between the worm gear 302 and the worm wheel 300 is smaller than the contact area of the meshing portion between other types of spur gears, for example. . Therefore, when the worm gear 302 applies a rotational force to the worm wheel 300, and when a 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 and Load, that is, stress concentrates on a very small part of the teeth of the worm wheel 300.
[0010]
Since stress concentrates on a very small part of the teeth of the worm gear 302 and the worm wheel 300 in this way, the teeth of the worm gear 302 and the worm wheel 300 must have sufficient mechanical strength, and thereby the metal It was necessary to use a material having high mechanical strength such as a material or to enlarge the worm gear 302 and the worm wheel 300. For this reason, it has been difficult to reduce the size and weight of the drive portion of the electric door mirror device.
[0011]
In consideration of the above fact, the present invention can prevent or effectively suppress the occurrence of abnormal noise and 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, It is an object 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 present invention as set forth in claim 1 is an electric door mirror device for turning the mirror main body between the retracted position and the unfolded position by the driving force of the motor, from the axially opposite ends to the axially central side. And a concave worm gear that is curved so that the outer dimension gradually decreases and the cross-sectional shape opens with a predetermined curvature outward in the radial direction of rotation, and meshes with the worm gear.UuOhm wheel,An engagement portion provided integrally with the drive shaft of the motor and projecting outward in the rotational radial direction of the drive shaft from the outer peripheral portion of the drive shaft, and an insertion hole into which the drive shaft is rotatably fitted Is formed in the shaft center portion, and an engagement hole having a pair of engagement walls facing around the shaft center of the insertion hole is formed, and the drive shaft is inserted in the insertion state of the drive shaft in the insertion hole. A drive gear in which the engaging portion is opposed to the pair of engaging walls around an axis ofThe worm gearThe rotational force of the drive gear viaThe worm wheelAttached toThe mirror main body is turned by rotation of the worm wheel by applying or rotation of the worm gear around the worm wheel by a reaction force according to the rotational force.
[0013]
  According to the electric door mirror device of the present invention according to claim 1,The drive shaft of the motor is rotatably inserted in an insertion hole formed in the drive gear. Therefore, basically, even if the drive shaft rotates simply by the driving force of the motor, the rotation of the drive shaft is not transmitted to the drive gear. 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 accommodated inside the drive gear. Therefore, when the engaging portion rotates together with the drive shaft and comes into contact with one of the pair of engaging walls along this rotational direction, and further when the drive shaft rotates in the same direction in this contact state, this engagement The engagement portion presses the pair of engagement walls provided in the hole in the rotation direction, and the drive gear is rotated.
Drive gearRotational forceIsDirectly or indirectly through a rotation transmission means such as a gear or through a speed reduction means constituted by such a rotation transmission means, it is transmitted to the worm gear, and the worm gear is rotated around its axis.
[0014]
The worm gear meshes with the worm wheel, and the worm gear imparts rotational force to the worm wheel.
[0015]
Here, when the worm wheel has a rotatable structure, the worm wheel that receives the rotational force of the worm gear rotates about its own axis, and the mirror body moves from the retracted position to the deployed position by the rotation of the worm wheel. Or swung from the deployed position to the retracted 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. Therefore, the worm gear, and thus the speed reduction means (rotation transmission means) and the motor described above rotate around the worm wheel by the reaction force from the worm wheel corresponding to the rotational force applied to the worm wheel by the worm gear. The rotation of the worm gear around the worm wheel causes the mirror body to pivot from the retracted position to the deployed position or from the deployed position to the retracted position.
[0017]
  By the way, as described above, the worm gear imparts 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 outer dimension from both axial end sides toward the center side, and the cross-sectional shape opens with a predetermined curvature toward the outer side in the rotational radius direction of the worm gear. The concave shape is curved likeThe
[0018]
The worm gear and the worm wheel having such a configuration are different from the meshing between the normal worm gear and the worm wheel, and the plurality of teeth of the worm gear mesh with the corresponding teeth of the worm wheel, and each meshing portion is mutually engaged. The contact area (contact area between the teeth of the worm gear and the teeth of the worm wheel) is larger than the contact area at the meshing portion between the normal worm gear and the worm wheel.
[0019]
As a result, the rotational force applied from the worm gear to the worm wheel and the reaction force applied from the worm wheel to the worm gear according to this rotational force are not concentrated unlike the normal worm gear and worm wheel, and are not concentrated in the meshing portions. In addition, the force applied per unit contact area is reduced.
[0020]
As described above, the rotational force and the reaction force are dispersed without being concentrated, so that 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 over a long period of time, the transmission loss of the rotational force and reaction force described above, the generation of abnormal noise due to the poor meshing between the worm wheel and the worm gear, and the rotational force Transmission loss can be effectively reduced or prevented.
[0021]
Further, the fact that the rotational force and reaction force are dispersed without concentrating in this way means that stress concentration on the teeth of the worm gear and the teeth of the worm wheel can be reduced. Accordingly, the mechanical strength of the worm gear or worm wheel can be set to be relatively low, and for example, the material of the worm gear or worm wheel can be changed from metal to synthetic resin material. For this reason, the manufacturing cost of the worm gear and the worm wheel is reduced, and the size and weight can be reduced.
[0022]
  As described above, since the worm gear and the worm wheel can be reduced in size and weight, the entire electric door mirror device can be reduced in size and weight.
Moreover, in the electric door mirror device according to the present invention, as described above, when the engaging portion presses the engaging wall, the rotational force of the drive shaft (that is, the drive force of the motor) is transmitted to the drive gear, and the drive gear Rotates.
More specifically, in this state, the motor is driven in a state where the engaging portion is in contact with one engaging wall (or at least separated from the other engaging wall toward the one engaging wall). 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.
For this reason, even if the initial torque immediately after the start of motor driving is set to be relatively small, the drive shaft can be smoothly and reliably started to rotate. Further, as described above, immediately after the start of driving of the motor, only the drive 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, and the drive gear Rotate.
Here, until the engaging portion comes into contact with the engaging wall as described above, the engaging portion is idled together with the drive shaft. The impact torque when the engaging portion comes into contact with the engaging wall due to the idling is larger than the impact torque of the structure in which the drive shaft and the drive gear are integrally connected in advance. For this reason, even if it uses a motor with small torque, a drive gear can be rotated reliably and rotation can be transmitted to a worm wheel.
The drive gear according to the third aspect of the present invention may be the worm gear according to the first aspect of the present invention or the prime mover gear according to the second aspect of the present invention, or the worm gear or the prime mover. Other gears constituting the rotation transmission means and the speed reduction means on the motor side from the gear may be used.
[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 of the present invention, wherein the driven gear is provided coaxially and integrally with the worm gear on the side in the axial direction of the worm gear. , The worm gearofThe opposite side to the worm wheelProvided inRotates by directly or indirectly receiving the driving force of the motorAnd meshing with the driven gear to rotate the driven gearDriving gear and the worm gearofThe opposite side of the driven gearProvided inThe worm gear and the driven gear are rotatably supported, and the worm gear at the shaft portion of the worm gear and the driven gear in the shaft support portion.ofAnd a shaft support portion that regulates displacement to the opposite side of the worm wheel.
[0024]
In the electric door mirror device according to the second aspect of the present invention, when the driving gear is rotated by the driving force of the motor, that is, the rotational force, the driven gear meshing with the driving gear is rotated. Since the driven gear is provided coaxially and integrally with the worm gear, the worm gear rotates integrally with the driven gear when the driven gear rotates. 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 in response 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 rotating force applied to the driven gear by the driving gear also acts in the direction of separating the driven gear from the driving gear.
[0026]
On the other hand, a reaction force acts on the worm gear from the worm wheel, and this reaction force tries to separate the worm gear from the worm wheel.
[0027]
  Here, in the electric door mirror device according to the present invention, the worm gear is used.ofOn the side opposite to the driven gear, the shaft portions of the worm gear and the driven gear are pivotally supported by the shaft support portion. The shaft support portion interferes with the shaft portion and restricts the shaft portion from being displaced to the side opposite to the worm wheel via the worm gear.
[0028]
  Accordingly, the reaction force when the shaft portion presses the shaft support portion and the pressing force based on the rotational force applied by the driving gear to the driven gear act on both ends of the worm gear in the axial direction. Driving gear is worm gearofSince it is provided on the opposite side of the worm wheel, the above pressing force and the reaction force from the shaft support portion are substantially in the same direction so as to counteract the force separating the worm gear from the worm wheel based on the reaction force from the worm wheel. Act on.
[0029]
In this way, the force that opposes the force that separates the worm gear from the worm wheel acts on both sides of the worm gear in the axial direction, 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, the meshing between the worm wheel and the worm gear can be maintained satisfactorily, so that the generation of noise due to the poor meshing between the worm wheel and the worm gear and the transmission loss of the rotational force are prevented. It can be effectively reduced or prevented.
The driving gear according to the second aspect of the present invention may be the driving gear according to the first aspect of the present invention.
[0039]
The drive gear according to the third aspect of the present invention may be the worm gear according to the first aspect of the present invention or the prime mover gear according to the second aspect of the present invention, or the worm gear or the prime mover. Other gears constituting the rotation transmission means and the speed reduction means on the motor side from the gear may be used.
[0040]
DETAILED DESCRIPTION OF THE INVENTION
<Configuration of the present embodiment>
FIG. 2 is a sectional view showing the configuration of the drive unit 12 of the electric door mirror device 10 according to the embodiment of the present invention. As shown in the figure, 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 | substrate 16 is being fixed to the stay which is not shown in figure, and is being fixed to the door panel of the vehicle which is not shown in figure via a stay.
[0041]
From the stand 14 constituting the substrate 16, a hollow (that is, pipe-shaped) shaft 18 is erected substantially upwardly of the vehicle. A base 20 formed of a synthetic resin material is disposed substantially above the stand 14. The base 20 is formed in a substantially bottomed cylindrical shape with an end on the substantially vehicle upper side opened. 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 can be rotated 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 axially supported by the shaft 18 so as to be coaxial with and rotatable with respect to the shaft 18. On the opposite side of the second worm wheel 90 via the bottom wall 22, a clutch panel 28 is arranged. Although a hole through which the shaft 18 passes is formed in the clutch panel 28, basically, the shaft 18 can be displaced along the axial direction but cannot be rotated around the shaft 18.
[0043]
Further, a compression coil spring 30 is fitted into the shaft 18 on the side opposite to the second worm wheel 90 via the clutch disk 28, and the urging force of the compression coil spring 30 causes the clutch disk 28 to move to the second worm wheel. The wheel 90 is pressed. The pressing force of the clutch panel 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 gap between the clutch panel 28 and the bottom wall 22 and the second worm wheel 90. Friction essentially disables rotation of the second worm wheel 90 relative to the bottom wall 22 and the shaft 18.
[0044]
On the other hand, a motor support board 36 is provided on the radially outer base 20 of the second worm wheel 90, and a motor 42 as drive means is attached on the motor support board 36. The drive shaft 44 of the motor 42 has an axial direction substantially the same as the axial direction of the shaft 18, and is rotatably fitted in a bearing hole 92 formed in the bottom wall 22 through the motor support plate 36. It is supported.
[0045]
Between the motor support board 36 and the bottom wall 22, the 1st worm gear 94 as a drive gear and a drive gear is arrange | positioned. 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 the outer peripheral portion thereof. Further, the inside of the first worm gear 94 is an insertion hole 96, and the drive shaft 44 of the motor 42 is loosely fitted.
[0046]
The first worm gear 94 is formed with an engagement hole 98 opened at one axial end (upper end) of the first worm gear 94, and the upper end of the insertion hole 96 is opened at the bottom of the engagement hole 98. ing. As shown in FIGS. 3 and 4A, the engagement hole 98 includes 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-shaped portion 102 is formed on one side radially outward of the large-diameter portion 100 via the center of the large-diameter portion 100, and the side opposite to the fan-shaped portion 102 via the large-diameter portion 100. A fan-shaped portion 102 is also formed.
[0047]
These fan-shaped parts 102 are formed in a fan shape in which the main part substantially coincides with the axis of the large-diameter part 100 and the insertion hole 96. Further, the fan-shaped portion 102 has a diameter dimension from the axis thereof to the arc-shaped portion of the fan sufficiently larger than the radial size of the large-diameter portion 100, and therefore the arc-shaped portion is first than the inner peripheral portion 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 includes a substantially cylindrical base 106. The outer diameter dimension of the base portion 106 is slightly smaller than the inner diameter dimension of the large diameter portion 100, and when the pressing piece 104 is accommodated in the engagement hole 98, the base portion 106 is inside the large diameter portion 100. And is rotatably inserted around the axis of the large diameter portion 100.
[0049]
The inner diameter of the base portion 106 is substantially equal to the outer diameter size of the drive shaft 44 of the motor 42 (strictly speaking, it is extremely slightly smaller), and the base portion 106 is press-fitted to the proximal end side of the drive shaft 44 and the base portion 106 and the drive shaft. 44 are connected to each other substantially integrally.
[0050]
On the other hand, a substantially rectangular parallelepiped rectangular piece 108 is extended from the outer peripheral portion of the base portion 106. The rectangular pieces 108 are formed so as to extend in directions opposite to each other via the base portion 106 (that is, a pair of rectangular pieces 108 are formed). The extension dimension of the rectangular piece 108 from the outer peripheral part of the base part 106 is slightly smaller than the length obtained by subtracting the radial dimension of the large-diameter part 100 from the radial dimension from the axis of the fan-shaped part 102 to the arc part. In the state of being inserted 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 of the rectangular piece 108 to the other surface along the direction of the axis of the large diameter portion 100) is one of the rectangular pieces 108 in the thickness direction. With one surface in the thickness direction of the other rectangular piece 108 being the other fan-shaped portion in a state where the surface of the other rectangular piece 108 is in contact with the engaging wall 102A which is the inner peripheral surface corresponding to the one side portion of the one fan-shaped portion 102. It is set so as to abut on an engagement wall 102A which is an inner peripheral surface corresponding to a portion of one side of 102.
[0052]
Therefore, when 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 both 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 is also in the fan-shaped portion 102. 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 accommodated in a gear accommodating portion 110 formed on the bottom wall 22. Further, as shown in FIG. 1, a first worm wheel 112 as a driven gear constituting the speed reduction means or the driving force transmission mechanism 11 is arranged on the side of the first worm gear 94. Part of the first worm wheel 112 is accommodated in the gear accommodating portion 110 formed on the bottom wall 22. A cylindrical boss 114 is formed coaxially and integrally with the first worm wheel 112 at one axial end of the first worm wheel 112.
[0054]
A shaft support portion 116 is provided in the gear housing portion 110 corresponding to the boss 114. The shaft support portion 116 is extended from the inner wall of the gear housing portion 110 so as to sandwich the boss 114 from the radially outer side of the boss 114, and the first worm wheel 112 is supported by the boss 114 being pivotally supported by the shaft support portion 116. One end side in the axial direction is supported rotatably. A worm gear accommodating 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 accommodated.
[0055]
The second worm gear 118 is provided such that its axis is located on an extension line of the axes of the first worm wheel 112 and the boss 114. In addition, as shown in FIG. 5, the second worm gear 118 is formed such that the diameter dimension at the center in the axial direction is shorter than the diameter dimension at both ends in the axial direction. The second worm gear 118 has a concave shape curved more than the radius of curvature at the outer peripheral portion of the second worm wheel 90 so as to open toward the outer side in the rotational radius direction.
[0056]
The second worm gear 118 meshes with the second worm wheel 90, and the direction of teeth of the second worm gear 118 that meshes with the second worm wheel 90 (the direction from the tooth root to the tooth tip) is approximately the second worm wheel 90. (Ie, the second worm gear 118 is a “drum worm” corresponding to the second worm wheel 90).
[0057]
As shown in FIG. 1, a shaft 120 is coaxially and integrally extended from one axial end of the second worm gear 118 (on the side opposite to the first worm wheel 112 via the second worm gear 118). . Corresponding to the shaft 120, a shaft support part 122 is formed in the worm gear housing part 124. The shaft support portion 122 has a wall shape facing each other through the shaft 120, and rotatably supports the shaft 120 by interfering with the shaft 120 from the radially outer side of the shaft 120.
[0058]
Furthermore, a shaft 126 is coaxially and integrally extended from the other axial end of the second worm gear 118 (on the side opposite to the shaft 120 via the second worm gear 118). The shaft 126 is press-fitted into the first worm wheel 112 from the boss 114 described above and is integrally coupled. As a result, the first worm wheel 112 and the second worm gear 118 are connected coaxially and integrally.
[0059]
A shaft support 128 is formed on the second worm gear 118 side of the shaft support 116 that supports the boss 114. The shaft support portion 128 has a wall shape facing each other through the shaft 126 like the shaft support portion 122, and supports the shaft 126 rotatably by interfering with the shaft 120 from the outside in the radial direction 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 includes the peripheral wall 50, and the covering portion 52 formed on the opposite side of the peripheral wall 50 from the peripheral wall 34 by fitting the peripheral wall 50 to the opening end of the peripheral wall 34 is a second worm wheel 90 or the like. The various members and the motor 42 arranged on the inner side of the peripheral wall 34 are substantially covered from the upper side of 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. Is fixed directly or indirectly.
[0062]
<Operation and effect of the present embodiment>
In the electric door mirror device 10, the drive shaft 44 rotates when electric power is supplied to the motor 42. Since the drive shaft 44 is merely loosely inserted into the insertion hole 96, the drive shaft 44 rotates within 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. By rotating the pressing piece 104, as shown in FIG. 4 (A), the rectangular piece 108 that has been in contact with the engaging wall 102A of the fan-shaped portion 102 until then is changed as shown in FIG. 4 (B). It leaves | separates from the engaging wall 102A and goes to the engaging wall 102B of the fan-shaped part 102. FIG.
[0063]
When the drive shaft 44 rotates from this state by a certain angle (for example, about 60 degrees), as shown in FIG. 4C, the rectangular piece 108 interferes with the engagement wall 102B. Further, when the drive shaft 44 rotates from this state, the rectangular piece 108 presses the engagement wall 102B toward the rotation direction of the drive shaft 44 as shown in FIG. Thereby, 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 electric door mirror device 10, even when electric power is supplied to the motor 42 as described above and the drive shaft 44 starts to rotate, the drive shaft 44 does not idle and rotates 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 driving of the motor 42 can be reduced, the motor 42 can be reliably operated, and the first worm gear 94 can be reliably rotated.
[0065]
As described above, when the first worm gear 94 is rotated by the driving force of the motor 42, this rotational force is transmitted to the second worm gear 118 via the first worm wheel 112, thereby rotating the second worm gear 118. The rotational force of the second worm gear 118 is transmitted to the second worm wheel 90 and tries to rotate the second worm wheel 90 around the shaft 18.
[0066]
However, as described above, friction is generated between the bottom wall 22 of the base 20 and the clutch disc 28 and the second worm wheel 90 by the pressing force of the clutch disc 28 based on the urging force of the compression coil spring 30. This friction prevents the second worm wheel 90 from rotating.
[0067]
Therefore, the second worm gear 118 is rotated around the second worm wheel 90 (that is, around the shaft 18) by the reaction force from the second worm wheel 90 corresponding to the pressing force applied by the second worm gear 118 to the second worm wheel 90. And the base 20 rotates around the shaft 18.
[0068]
The base 20 is fixed to the bracket 82 between the unfolded position where the rear of the vehicle can be visually recognized by the mirror main body and the retracted position where the reflecting surface of the mirror main body faces substantially inward in the vehicle width direction (substantially the vehicle interior side). The frame not shown rotates.
[0069]
Incidentally, 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 rotational circumferential direction of the second worm wheel 90 and a component outward in the rotational radial direction of the second worm wheel 90. The reaction force (external force) F <b> 1 that is the other component acts to separate the second worm gear 118 from the second worm wheel 90.
[0070]
Here, when the second worm gear 118 is to be separated from the second worm wheel 90 by such a reaction force F1, the shaft support portions 122 are located on both sides in the axial direction of the second worm gear 118 from the side opposite to the direction in which the reaction force F1 acts. A reaction force F2 that interferes with the shafts 120 and 126 and is generated when the shafts 120 and 126 press the shaft support portions 122 and 128 is applied from the shaft support portions 122 and 128 to the shafts 120 and 126.
[0071]
As described above, in the electric door mirror device 10, both the shaft support parts 122 generate a reaction force opposite to the reaction force F <b> 1 against the reaction force F <b> 1 applied to the second worm gear 118 on both sides in the axial direction of the second worm gear 118. By imparting to the shafts 120 and 126, a balance (balance) is achieved, and the tilt of the second worm gear 118 and the shafts 120 and 126 can be effectively suppressed or prevented.
[0072]
As described above, the inclination of the second worm gear 118 and the shafts 120 and 126 can be suppressed or prevented, so that the meshing between the second worm wheel 90 and the second worm gear 118 can be maintained satisfactorily. It is possible to prevent or effectively reduce the generation of abnormal noise and the transmission loss of rotational force due to the lowering of the meshing property with the second worm gear 118.
[0073]
On the other hand, when the first worm wheel 112 tries to incline due to the external force F3, which is a component radially outward of the rotational force from the first worm gear 94, acting on the first worm wheel 112, the boss 114 is The shaft support 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 1st worm wheel 112 is prevented or effectively suppressed.
[0074]
As described above, the tilt of the first worm wheel 112 is prevented or effectively suppressed, whereby the tilt of the second worm gear 118 due to the external force F3 can be prevented or effectively suppressed. Accordingly, it is possible to prevent or effectively reduce the generation of abnormal noise and the transmission loss of the rotational force due to the lowering of 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 size from the both axial ends toward the axial center, and the cross-sectional shape thereof is a concave shape curved more than the radius of curvature at the outer peripheral portion of the second worm wheel 90. In addition, the teeth of the second worm gear 118 are generally directed toward the center of rotation 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 plurality of 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 tips and side surfaces of the teeth of the second worm gear 118 in the engaged state. Thus, 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 with the side surfaces of the teeth of the second worm wheel 90 against the side surfaces of the plurality of teeth of the second worm gear 118. 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 second worm gear 118 and the shaft 120 from tilting. As a result, the generation of abnormal noise caused by the lowering of the meshing property between the second worm wheel 90 and the second worm gear 118 Transmission loss of rotational force can be prevented or effectively reduced.
[0078]
Further, as described above, 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 distributed over many teeth, so that the second worm wheel 90 and the second worm wheel 90 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. Thereby, 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 as described above, the entire electric door mirror device 10 can be reduced in size and weight.
[0081]
In the present embodiment, both shafts 120 and 126 are supported by the shaft support portions 122 and 128. However, only the shaft 120 is supported by the shaft support portion 122 and the shaft support portions 116 and 128 are not provided. However, the reaction force F1 of the shaft support 122 and the external force F3 from the first worm gear 94 may be opposed to the reaction force F1.
[0082]
【The invention's effect】
As described above, in the present invention, the meshing between the worm gear and the worm wheel can be maintained satisfactorily, and the transmission loss of the rotational force and the generation of abnormal noise due to the meshing failure can be effectively prevented or reduced. In addition, since the load during transmission of the rotational force and the reaction force according to this rotational force is distributed without being concentrated on a part of the teeth of the worm gear or worm wheel, the mechanical strength of the worm gear or 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 to 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 showing a configuration of a drive 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 transmission member.
FIGS. 4A and 4B are plan views of a worm gear as a rotation transmission member, in which FIG. 4A is a state before the start of rotation of the drive shaft, FIG. 4B is a state immediately after the start of rotation of the drive shaft, and FIG. Rotated state, (D) shows a state where the drive shaft has rotated beyond a predetermined angle.
FIG. 5 is a plan sectional view showing a meshed state between a worm gear and a worm wheel.
FIG. 6 is a diagram showing a reaction force that a worm gear receives from a worm wheel.
[Explanation of symbols]
10 Electric door mirror device
42 motor
44 Drive shaft
90 Second 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 Second worm gear (worm gear)
122 Shaft support

Claims (2)

An electric door mirror device for rotating the mirror body between a retracted position and a deployed position by a driving force of a motor,
A concave worm gear whose outer dimension gradually decreases from both axial ends toward the axial center, and whose cross-sectional shape is curved so as to open with a predetermined curvature outward in the radial direction of rotation,
And if Uhh ohm wheel bite to the worm gear,
An engagement portion provided integrally with the drive shaft of the motor and projecting outward in the rotational radial direction of the drive shaft from the outer peripheral portion of the drive shaft;
An insertion hole into which the drive shaft is rotatably inserted is formed in the shaft center portion, and an engagement hole having a pair of engagement walls facing around the shaft center of the insertion hole is formed, and the insertion hole is connected to the insertion hole. A drive gear in which the engagement portion is opposed to the pair of engagement walls around the axis of the drive shaft in the inserted state of the drive shaft;
Wherein the by the rotation of the worm gear of the surrounding worm wheel due to the reaction force corresponding to the rotation or the rotational force of the worm wheel due to granting the rotational force of the drive gear to the worm wheel through the worm gear Swivel the mirror body,
An electric door mirror device. A driven gear provided coaxially and integrally with the worm gear on an axial side of the worm gear;
The said worm wheel of the worm gear provided on the opposite side, the rotating driving force of the motor directly or indirectly received by, meshes with the driven gear, and a driving gear for rotating the driven gear,
Wherein the said driven gear of the worm gear provided on the opposite side, the worm gear and thereby rotatably supported to the driven gear, the worm of the worm gear of the shaft portion of the worm gear and the driven gear in the axial journal section A shaft support that regulates displacement to the opposite side of the wheel,
The electric door mirror device according to claim 1, comprising:

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