Patent Publication Number: US-2023143257-A1

Title: Flow deflecting device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority under 35 USC 119 from Japanese Patent Application No. 2021-183575 filed on Nov. 10, 2021, the disclosure of which is incorporated by reference herein in its entirety. 
     BACKGROUND 
     Technical Field 
     The disclosure relates to a flow deflecting device that reduces airflow to a front wheel of a vehicle. 
     Related Art 
     Japanese Patent Application Laid-open (JP-A) No. 2019-93785 discloses a flow deflecting device for a vehicle where projections (pushed portions) of a second collar member on a drive device side are inserted by the biasing force of a spring into recesses of a first collar member on a flow deflecting member side, and when an external force acts on the flow deflecting member such that the first collar member is rotated relative to the second collar member, rotation of the flow deflecting member is allowed. 
     In this flow deflecting device, in order for the flow deflecting member to be rotated due to action of an external force (in order for the first collar member to be rotated relative to the second collar member), a load for disengaging the projections of the second collar member from the recesses of the first collar member counter to the biasing force of the spring is necessary. 
     SUMMARY 
     In view of the above circumstances, the present disclosure obtains a flow deflecting device that can inhibit the load for the flow deflecting member to be rotated in a retraction direction due to action of an external force from becoming higher. 
     A flow deflecting device of a first aspect of the disclosure includes: a flow deflecting body configured to be rotated in a deployment direction so as to become deployed to a front side of a front wheel of a vehicle and reduce airflow to the front wheel, and configured to be rotated in a retraction direction so as to become retracted in a vehicle body; a rotational mechanism, whereby the flow deflecting body is rotatable in an engaged state at the rotational mechanism, such that in a case in which the flow deflecting body in a deployed position is acted upon by an external force and engagement is released, the flow deflecting body is configured to be rotated in the retraction direction, and in a case in which the flow deflecting body in a retracted position is acted upon by an external force, the flow deflecting body is configured to be rotated in the retraction direction in the engaged state at the rotational mechanism; and a limiting mechanism, whereby rotation of the flow deflecting body is limitable in an engaged state at the limiting mechanism, such that in a case in which the flow deflecting body in the retracted position is acted upon by an external force and engagement is released, the flow deflecting body is configured to be rotated in the retraction direction, and in a case in which the flow deflecting body in the deployed position is acted upon by an external force, the flow deflecting body is configured to be rotated in the retraction direction in the engaged state at the limiting mechanism. 
     A flow deflecting device of a second aspect of the disclosure is the flow deflecting device of the first aspect of the disclosure, wherein, in a state in which the flow deflecting body is disposed in the deployed position, the rotational mechanism limits rotation of the flow deflecting body in the retraction direction and the limiting mechanism limits rotation of the flow deflecting body in the deployment direction. 
     A flow deflecting device of a third aspect of the disclosure is the flow deflecting device of the first aspect or the second aspect of the disclosure, wherein, in a case in which the flow deflecting body is disposed in the retracted position, the rotational mechanism limits rotation of the flow deflecting body in the deployment direction and the limiting mechanism limits rotation of the flow deflecting body in the retraction direction. 
     A flow deflecting device of a fourth aspect of the disclosure is the flow deflecting device of any one of the first aspect to the third aspect of the disclosure, wherein, in a case in which the flow deflecting body in the deployed position is rotated in the retraction direction due to action of an external force, the limiting mechanism allows rotation of the flow deflecting body. 
     A flow deflecting device of a fifth aspect of the disclosure is the flow deflecting device of any one of the first aspect to the fourth aspect of the disclosure, wherein, when the flow deflecting body in the retracted position is rotated in the retraction direction due to action of an external force, the rotational mechanism allows rotation of the flow deflecting body. 
     In the flow deflecting device of the first aspect of the disclosure, in a case in which the flow deflecting body is rotated in the deployment direction, the flow deflecting body becomes deployed to the front side of the front wheel of the vehicle and reduces airflow to the front wheel. Moreover, when the flow deflecting body is rotated in the retraction direction, the flow deflecting body becomes retracted in the vehicle body. 
     Furthermore, the rotational mechanism is engaged and the flow deflecting body is rotated. Moreover, the limiting mechanism is engaged and rotation of the flow deflecting body is limited. 
     Here, in a case in which the flow deflecting body in the deployed position is acted upon by an external force such that the engagement of the rotational mechanism is released in a state in which the limiting mechanism is engaged with the flow deflecting body, the flow deflecting body is rotated in the retraction direction. 
     The engagement of the limiting mechanism with the flow deflecting body does not become released, so the load for the flow deflecting body to be rotated in the retraction direction can be inhibited from becoming higher. 
     Moreover, in a case in which the flow deflecting body in the retracted position is acted upon by an external force such that the engagement of the limiting mechanism is released in a state in which the rotational mechanism is engaged with the flow deflecting body, the flow deflecting body is rotated in the retraction direction. The engagement of the rotational mechanism with the flow deflecting body does not become released, so the load for the flow deflecting body to be rotated in the retraction direction can be inhibited from becoming higher. 
     In the flow deflecting device of the second aspect of the disclosure, in a case in which the flow deflecting body is disposed in the deployed position, the rotational mechanism limits rotation of the flow deflecting body in the retraction direction and the limiting mechanism limits rotation of the flow deflecting body in the deployment direction. Rotation of the flow deflecting body in the deployment direction and the retraction direction can be limited and rattling of the flow deflecting body can be inhibited. 
     In the flow deflecting device of the third aspect of the disclosure, in a case in which the flow deflecting body is disposed in the retracted position, the rotational mechanism limits rotation of the flow deflecting body in the deployment direction and the limiting mechanism limits rotation of the flow deflecting body in the retraction direction. Rotation of the flow deflecting body in the deployment direction and the retraction direction can be limited and rattling of the flow deflecting body can be inhibited. 
     In the flow deflecting device of the fourth aspect of the disclosure, in a case in which the flow deflecting body in the deployed position is rotated in the retraction direction due to the action of an external force, the limiting mechanism allows rotation of the flow deflecting body. The load for the flow deflecting body to be rotated in the retraction direction can be effectively inhibited from becoming higher. 
     In the flow deflecting device of the fifth aspect of the disclosure, in a case in which the flow deflecting body in the retracted position is rotated in the retraction direction due to the action of an external force, the rotational mechanism allows rotation of the flow deflecting body. The load for the flow deflecting body to be rotated in the retraction direction can be effectively inhibited from becoming higher. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a side view showing a front portion of a vehicle in an embodiment of the disclosure as viewed from outside in the vehicle width direction; 
         FIG.  2    is an exploded perspective view showing a flow deflecting device pertaining to the embodiment of the disclosure as viewed from inside in the vehicle width direction and below; 
         FIG.  3 A  is a sectional view showing main parts of the flow deflecting device pertaining to the embodiment of the disclosure and shows when a flow deflecting body is disposed in a retracted position; and 
         FIG.  3 B  is a sectional view showing main parts of the flow deflecting device pertaining to the embodiment of the disclosure and shows when the flow deflecting body is disposed in a deployed position. 
     
    
    
     DETAILED DESCRIPTION 
     In  FIG.  1    a front portion of a vehicle  12  in an embodiment of the disclosure is shown in a side view as viewed from outside in the vehicle width direction (the vehicle right direction), and in  FIG.  2    a flow deflecting device  10  pertaining to the embodiment is shown in an exploded perspective view as viewed from inside in the vehicle width direction and below. In the drawings, arrow FR indicates a forward direction of the vehicle, arrow OUT indicates an outward direction in the vehicle width direction (a rightward direction of the vehicle), and arrow UP indicates an upward direction. 
     As shown in  FIG.  1   , the flow deflecting device  10  pertaining to the embodiment is installed inside a front end portion of a vehicle body  12 A and is disposed on the front side of a front wheel  12 B of the vehicle  12 . 
     As shown in  FIG.  2   , the flow deflecting device  10  is provided with a flow deflecting body  14  (an air spat) made of resin, and the flow deflecting body  14  is disposed in a retracted position (the position represented by the dashed lines in  FIG.  1   ). The vehicle front end portion of the flow deflecting body  14  is configured as an attachment box  14 A substantially in the shape of a cuboid box and serving as an attachment portion, and the inside of the attachment box  14 A opens inward in the vehicle width direction. The portion of the flow deflecting body  14  on the vehicle rear side of the attachment box  14 A is configured as a flow deflecting portion  14 B substantially in the shape of a cuboid box, and the flow deflecting portion  14 B is integrated at its inner end portion in the vehicle width direction with the attachment box  14 A and the inside of the flow deflecting portion  14 B opens upward and in the vehicle rearward direction. 
     An attachment  16  that is made of resin, has an outer shape substantially in the shape of a rectangular tube, and serves as an attachment member is mated with the inside of the attachment box  14 , and the attachment  16  is secured at its peripheral wall to a bottom wall (outer wall in the vehicle width direction) of the attachment box  14 A. The inside of the attachment  16  is substantially in the shape of a cylinder and opens to both sides in the vehicle width direction. A disc-shaped partition wall (not shown in the drawings) is integrally formed inside the attachment  16 , and the partition wall partitions the inside of the attachment  16  into a vehicle width direction outer portion and a vehicle width direction inner portion. 
     A drive device  18  is attached to the attachment  16 , and the drive device  18  is secured to the inside of the front end portion of the vehicle body  12 A. 
     The drive device  18  is provided with a stand  22  that is made of metal, is substantially in the shape of a cylinder, and serves as a limit receiving member (rotating shaft) configuring a limiting mechanism  20 , and an outer end portion in the vehicle width direction of the stand  22  is coaxially increased in diameter. An outer end portion in the vehicle width direction of the stand  22  is mated with the inside of the attachment  16  and secured to the partition wall of the attachment  16 , and the attachment  16  and the flow deflecting body  14  are configured to be rotatable in a deployment direction A and a retraction direction B integrally with the stand  22  about the stand  22  as a central axis. 
     On the outer end portion in the vehicle width direction of the stand  22 , plural (in this embodiment, four) limiting projections  22 A (see  FIG.  3 A ) having trapezoidal cross-sectional shapes and serving as limit receiving portions are integrally formed, and the plural limiting projections  22 A are arranged equidistantly in the circumferential direction of the stand  22 . The limiting projections  22 A project inward in the vehicle width direction and are curved along the circumferential direction of the stand  22 . The deployment direction A-side surfaces of the limiting projections  22 A are perpendicular to the circumferential direction of the stand  22 , and the retraction direction B-side surfaces of the limiting projections  22 A are inclined in a direction inward in the vehicle width direction heading in the deployment direction A. 
     On an inner side in the vehicle width direction of the attachment  16 , a case  24  that is made of resin, is substantially in the shape of a cuboid box, and serves as a limiting member configuring the limiting mechanism  20  is disposed, and the inside of the case  24  opens inward in the vehicle width direction. The stand  22  runs through and is mated with the vehicle front portion of a bottom wall (vehicle width direction outer wall) of the case  24 , and the stand  22  is rotatably supported on the bottom wall of the case  24  and movement of the stand  22  inward in the vehicle width direction is regulated by the bottom wall of the case  24 . 
     In the bottom wall of the case  24 , plural (in this embodiment, four) limiting recesses  24 A (see  FIG.  3 A ) having trapezoidal cross-sectional shapes and serving as limiting portions are formed around the stand  22 , and the plural limiting recesses  24 A are arranged equidistantly relative to the circumferential direction of the stand  22 . The limiting recesses  24 A open outward in the vehicle width direction and extend in the circumferential direction of the stand  22 . The deployment direction A-side end surfaces of the limiting recesses  24 A are perpendicular to the circumferential direction of the stand  22 , and the retraction direction B-side end surfaces of the limiting recesses  24 A are inclined in a direction inward in the vehicle width direction heading in the deployment direction A. The limiting projections  22 A of the stand  22  are inserted into (engaged with) the limiting recesses  24 A, and the limiting projections  22 A are brought into abutment with the retraction direction B-side end surfaces of the limiting recesses  24 A so that rotation of the stand  22  in the retraction direction B is limited. 
     Inside an inner portion in the vehicle width direction of the case  24 , a motor base  26  made of resin and serving as a retention member is secured. At the vehicle front portion of the motor base  26 , a housing tube  26 A substantially in the shape of a bottomed cylindrical tube is formed, and the inside of the housing tube  26 A opens outward in the vehicle width direction and the stand  22  is coaxially housed inside the housing tube  26 A. On the vehicle rear portion of the motor base  26 , a retention tube  26 B substantially in the shape of a bottomed elliptical tube is integrally formed, and the inside of the retention tube  26 B opens inward in the vehicle width direction. 
     At an inner side in the vehicle width direction of the case  24  and the motor base  26 , a cover  28  that is made of resin, is substantially in the shape of a cuboid box, and serves as a cover member is provided, and the inside of the cover  28  opens outward in the vehicle width direction. An inner end portion in the vehicle width direction of the case  24  is mated with and secured to the inside in the vehicle width direction of an outer end portion of the cover  28 , and the cover  28  covers the inner side in the vehicle width direction of the case  24  and the motor base  26 . 
     The case  24  and the cover  28  are secured to the inside of the front end portion of the vehicle body  12 A, whereby the drive device  18  is secured to the inside of the front end portion of the vehicle body  12 A. 
     In a space between the case  24  and the cover  28 , a motor  30  serving as a drive device is provided. The motor  30  is provided with a body portion  30 A substantially in the shape of an elliptical cylinder, and the body portion  30 A is fitted from an inner side in the vehicle width direction into and retained inside the retention tube  26 B of the motor base  26 . An output shaft  30 B extends outward in the vehicle width direction from the body portion  30 A, and the output shaft  30 B extends through a bottom wall (vehicle width direction outer wall) of the retention tube  26 B to an outer side in the vehicle width direction of the motor base  26 . The motor  30  is driven to rotate the output shaft  30 B. 
     The case  24  is provided with a gear mechanism  32 . 
     The gear mechanism  32  is provided with a primary worm  34  made of resin on an outer side in the vehicle width direction of the motor  30 , and an outer end portion of the primary worm  34  is supported so as to be freely rotatable on the bottom wall of the case  24 . The output shaft  30 B of the motor  30  is coaxially inserted from an inner side in the vehicle width direction into the primary worm  34 , and when the output shaft  30 B is rotated, the primary worm  34  is rotated integrally with the output shaft  30 B. 
     The gear mechanism  32  is also provided with an output worm  36  made of metal on the upper side of the primary worm  34 , and the output worm  36  is supported so as to be freely rotatable between the bottom wall of the case  24  and the motor base  26 . On the lower side of the output worm  36 , a primary gear  38  (a worm wheel) made of resin is coaxially supported, and the primary gear  38  is rotated integrally with the output worm  36 . The primary gear  38  is meshed with the primary worm  34 , and when the primary worm  34  is rotated, the primary gear  38  and the output worm  36  are integrally rotated. 
     The gear mechanism  32  is also provided with an output gear  42  (a worm wheel) made of metal and serving as a rotational member configuring a rotational mechanism  40  on the vehicle front side of the output worm  36 . The stand  22  coaxially runs through and is mated with the output gear  42 , and the output gear  42  is rotatably supported on the stand  22 . The output gear  42  is configured to be movable in the vehicle width direction (axial direction) relative to the stand  22 , and the output gear  42  is brought into abutment from an inner side in the vehicle width direction with the bottom wall of the case  24  so that movement of the output gear  42  outward in the vehicle width direction is regulated. The output gear  42  is meshed with the output worm  36  so that rotation of the output gear  42  is limited, and when the output worm  36  is rotated, the output gear  42  is rotated. 
     A cylindrical recess  42 A is coaxially formed at an inner surface in the vehicle width direction of the output gear  42 , and the recess  42 A opens inward in the vehicle width direction. At an outer surface in the vehicle width direction of the recess  42 A, plural (in this embodiment, four) rotational recesses  42 B (see  FIG.  3 A ) serving as rotational portions are formed, and the plural rotational recesses  42 B are arranged equidistantly in the circumferential direction of the output gear  42 . The rotational recesses  42 B open inward in the vehicle width direction and extend in the circumferential direction of the output gear  42 . The rotational recesses  42 B have trapezoidal cross-sectional shapes, and both end surfaces of each of the rotational recesses  42 B are inclined in a direction inward in the vehicle width direction heading toward circumferential direction outer sides of the output gear  42 . 
     At an inner side in the vehicle width direction of the output gear  42 , a clutch  44  that is made of metal, is substantially in the shape of a cylindrical tube, and serves as a rotation receiving member configuring the rotational mechanism  40  is provided. The stand  22  coaxially runs through the clutch  44 , and the clutch  44  is supported thereon, so as to be integrally rotatable with the stand  22 . The clutch  44  is configured to be movable in the vehicle width direction relative to the stand  22 , and is fitted inside the recess  42 A of the output gear  42 . 
     On an outer surface in the vehicle width direction of the clutch  44 , plural (in this embodiment, four) rotational projections  44 A (see  FIG.  3 A ) serving as rotation receiving portions are formed, and the plural rotational projections  44 A are arranged equidistantly in the circumferential direction of the clutch  44 . The rotational projections  44 A project outward in the vehicle width direction and are curved along the circumferential direction of the clutch  44 . The rotational projections  44  have trapezoidal cross-sectional shapes, and both side surfaces of each of the rotational projections  44 A are inclined in a direction outward in the vehicle width direction heading toward the clutch  44  circumferential direction inner sides. The rotational projections  44 A are inserted into (engaged with) rotational recesses  42 B of the output gear  42 , and the rotational projections  44 A are brought into abutment with the deployment direction A-side end surfaces of the rotational recesses  42 B so that rotation of the clutch  44  in the deployment direction A is limited. 
     The stand  22  is coaxially inserted into a compression coil spring  46  made of metal and serving as a biasing member on an inner side in the vehicle width direction of the clutch  44 . A push nut  48  that is made of metal, is substantially in the shape of an annular disc, and serves as an engagement member is mated with and secured to an inner end portion in the vehicle width direction of the stand  22 , and the compression coil spring  46  bridges the push nut  48  and the clutch  44 . The compression coil spring  46  is compressed in the axial direction, biases the push nut  48  and the stand  22  inward in the vehicle width direction, and biases the clutch  44  in the direction of the output gear  42  (outward in the vehicle width direction). 
     Next, the action of this embodiment will be described. 
     In the flow deflecting device  10  having the above configuration, when, in the drive device  18 , the motor  30  is forwardly driven so that the output shaft  30 B, the primary worm  34 , the primary gear  38 , and the output worm  36  are rotated, the output gear  42  is rotated in the deployment direction A and the retraction direction B-side end surfaces of the rotational recesses  42 B of the output gear  42  are brought into abutment with the rotational projections  44 A of the clutch  44 . The clutch  44 , the stand  22 , and the attachment  16  are rotated integrally with the output gear  42  in the deployment direction A, and the flow deflecting body  14  is rotated in the deployment direction A. Moreover, the limiting projections  22 A of the stand  22  are brought into abutment with the deployment direction A-side end surfaces of the limiting recesses  24 A of the case  24  so that rotation of the stand  22  in the deployment direction A is limited (see  FIG.  3 B ), whereby rotation of the flow deflecting body  14  in the deployment direction A is limited and the flow deflecting body  14  is disposed in a deployed position (the position represented by the long dashed double-short dashed lines in  FIG.  1   ). The flow deflecting portion  14 B of the flow deflecting body  14  is disposed on the vehicle front side of the front wheel  12 B of the vehicle  12  on the underside of the vehicle body  12 A and reduces the headwind (airflow) in the direction of the front wheel  12 B created by the forward motion of the vehicle  12  (deflects the headwind toward the underside of the front wheel  12 B), whereby an increase in air pressure on the vehicle front side of the front wheel  12 B is inhibited and the air resistance and lift of the vehicle  12  are reduced. 
     Conversely, when, in the drive device  18 , the motor  30  is reversely rotated so that the output shaft  30 B, the primary worm  34 , the primary gear  38 , and the output worm  36  are rotated, the output gear  42  is rotated in the retraction direction B and the deployment direction A-side end surfaces of the rotational recesses  42 B of the output gear  42  are brought into abutment with the rotational projections  44 A of the clutch  44 . The clutch  44 , the stand  22 , and the attachment  16  are rotated integrally with the output gear  42  in the retraction direction B, and the flow deflecting body  14  is rotated in the retraction direction B. Moreover, the limiting projections  22 A of the stand  22  are brought into abutment with the retraction direction B-side end surfaces of the limiting recesses  24 A of the case  24  so that rotation of the stand  22  in the retraction direction B is limited (see  FIG.  3 A ), whereby rotation of the flow deflecting body  14  in the retraction direction B is limited and the flow deflecting body  14  is disposed in the retracted position (the position represented by the dashed lines in  FIG.  1   ). 
     Furthermore, when the flow deflecting body  14  is disposed in the deployed position, when an external force equal to or greater than a predetermined value in the upward direction acts on the airflow deflecting portion  14 B of the flow deflecting body  14  from a bump on the surface on which the vehicle  12  is traveling, the clutch  44  is moved inward in the vehicle width direction counter to the biasing force of the compression coil spring  46  and at the same time the rotational projections  44 A of the clutch  44  become disengaged (their engagement is released) in the retraction direction B from the rotational recesses  42 B of the output gear  42 . Together with this, the limiting projections  22 A of the stand  22  are rotated in the retraction direction B in the limiting recesses  24 A of the case  24  (see the long dashed double-short dashed lines in  FIG.  3 B ). For this reason, the flow deflecting body  14 , the attachment  16 , the stand  22 , and the clutch  44  are rotated in the retraction direction B so that the flow deflecting body  14 , the attachment  16 , and the drive device  18  are protected. 
     Thereafter, when the flow deflecting body  14  is rotatable in the deployment direction A, when the motor  30  is reversely driven, the output gear  42  is rotated in the retraction direction B so that the rotational projections  44 A of the clutch  44  are brought into abutment with the retraction direction B-side end surfaces of the rotational recesses  42 B of the output gear  42 . Then, the motor  30  is forwardly driven, whereby the output gear  42 , the clutch  44 , and the stand  22  are rotated in the deployment direction A so that the flow deflecting body  14  is rotated (returned) to the deployed position. 
     Moreover, when the flow deflecting body  14  is disposed in the retracted position, when an external force equal to or greater than a predetermined value in the upward direction acts on the airflow deflecting portion  14 B of the flow deflecting body  14  from a bump on the surface on which the vehicle  12  is traveling, the stand  22  is moved outward in the vehicle width direction counter to the biasing force of the compression coil spring  46  and at the same time the limiting projections  22 A of the stand  22  become disengaged (their engagement is released) in the retraction direction B from the limiting recesses  24 A of the case  24 . Together with this, the rotational projections  44 A of the clutch  44  are rotated in the retraction direction B in the rotational recesses  42 B of the output gear  42  (see the long dashed double-short dashed lines in  FIG.  3 A ). The flow deflecting body  14 , the attachment  16 , the stand  22 , and the clutch  44  are rotated in the retraction direction B so that the flow deflecting body  14 , the attachment  16 , and the drive device  18  are protected. 
     Thereafter, when the flow deflecting body  14  is rotatable in the deployment direction A, when the motor  30  is forwardly driven, the output gear  42  is rotated in the deployment direction A. The retraction direction B-side end surfaces of the rotational recesses  42 B of the output gear  42  are brought into abutment with the rotational projections  44 A of the clutch  44  so that the clutch  44  and the stand  22  are rotated integrally with the output gear  42  in the deployment direction A, whereby the flow deflecting body  14  is rotated (returned) to the retracted position. Then, the motor  30  is reversely driven, whereby the output gear  42  is rotated in the retraction direction B so that the deployment direction A-side end surfaces of the rotational recesses  42 B of the output gear  42  are brought into abutment with the rotational projections  44 A of the clutch  44 . 
     When the flow deflecting body  14  in the deployed position is rotated in the retraction direction B due to action of an external force, the rotational projections  44 A of the clutch  44  become disengaged from the rotational recesses  42 B of the output gear  42  (see the long dashed double-short dashed lines in  FIG.  3 B ) in a state in which the limiting projections  22 A of the stand are inserted into the limiting recesses  24 A of the case  24 . The limiting projections  22 A do not become disengaged from the limiting recesses  24 A, so the load for the flow deflecting body  14  to be rotated in the retraction direction B from the deployed position (the force counter to the biasing force of the compression coil spring  46 ) can be inhibited from becoming higher. 
     Moreover, when the flow deflecting body  14  in the deployed position is rotated in the retraction direction B due to action of an external force, the limiting projections  22 A of the stand  22  are rotated without being hindered by the limiting recesses  24 A of the case  24  (the limiting recesses  24 A allow rotation of the limiting projections  22 A). For this reason, the load for the flow deflecting body  14  to be rotated in the retraction direction B from the deployed position can be effectively inhibited from becoming higher. 
     Furthermore, when the flow deflecting body  14  in the retracted position is rotated in the retraction direction B due to action of an external force, the limiting projections  22 A of the stand  22  become disengaged from the limiting recesses  24 A of the case  24  in a state in which the rotational projections  44 A of the clutch  44  are inserted into the rotational recesses  42 B of the output gear  42  (see the long dashed double-short dashed lines in  FIG.  3 A ). The rotational projections  44 A do not become disengaged from the rotational recesses  42 B, so the load for the flow deflecting body  14  to be rotated in the retraction direction B from the retracted position (the force counter to the biasing force of the compression coil spring  46 ) can be inhibited from becoming higher. 
     Moreover, when the flow deflecting body  14  in the retracted position is rotated in the retraction direction B due to action of an external force, the rotational projections  44 A of the clutch  44  are rotated without being hindered by the rotational recesses  42 B of the output gear  42  (the rotational recesses  42 B allow rotation of the rotational projections  44 A). For this reason, the load for the flow deflecting body  14  to be rotated in the retraction direction B from the retracted position can be effectively inhibited from becoming higher. 
     Furthermore, when the flow deflecting body  14  is disposed in the deployed position (see  FIG.  3 B ), the rotational projections  44 A of the clutch  44  are in abutment with the retraction direction B-side end surfaces of the rotational recesses  42 B of the output gear  42  so that rotation of the clutch  44  in the retraction direction B is limited, whereby rotation of the flow deflecting body  14  in the retraction direction B is limited. Moreover, the limiting projections  22 A of the stand  22  are in abutment with the deployment direction A-side end surfaces of the limiting recesses  24 A of the case  24  so that rotation of the stand  22  in the deployment direction A is limited, whereby rotation of the flow deflecting body  14  in the deployment direction A is limited. Rotation of the flow deflecting body  14  in the deployment direction A and the retraction direction B from the deployed position can be limited, and rattling of the flow deflecting body  14  can be inhibited. 
     Moreover, when the flow deflecting body  14  is disposed in the retracted position (see  FIG.  3 A ), the rotational projections  44 A of the clutch  44  are in abutment with the deployment direction A-side end surfaces of the rotational recesses  42 B of the output gear  42  so that rotation of the clutch  44  in the deployment direction A is limited, whereby rotation of the flow deflecting body  14  in the deployment direction A is limited. Moreover, the limiting projections  22 A of the stand  22  are in abutment with the retraction direction B-side end surfaces of the limiting recesses  24 A of the case  24  so that rotation of the stand  22  in the retraction direction B is limited, whereby rotation of the flow deflecting body  14  in the retraction direction B is limited. Rotation of the flow deflecting body  14  in the deployment direction A and the retraction direction B from the retracted position can be limited, and rattling of the flow deflecting body  14  can be inhibited. 
     In this embodiment, the stand  22  is provided with the limiting projections  22 A and the case  24  is provided with the limiting recesses  24 A. However, the stand  22  may be provided with the limiting recesses  24 A and the case  24  may be provided with the limiting projections  22 A. In this case, the retraction direction B-side surfaces of the limiting projections  22 A and the retraction direction B-side end surfaces of the limiting recesses  24 A may be perpendicular to the circumferential direction of the stand  22 , and the deployment direction A-side surfaces of the limiting projections  22 A and the deployment direction A-side end surfaces of the limiting recesses  24 A may be inclined in a direction inward in the vehicle width direction heading in the deployment direction A. 
     Furthermore, in this embodiment, the output gear  42  is provided with the rotational recesses  42 B and the clutch  44  is provided with the rotational projections  44 A. However, the output gear  42  may he provided with the rotational projections  44 A and the clutch  44  may be provided with the rotational recesses  42 B.