JP2015205613A - Outer mirror device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively reduce aerodynamic noise of which sound source is an outer mirror device for vehicle, and to improve quietness inside a cabin.SOLUTION: An outer mirror device for vehicle, which is installed outside a vehicle body, comprises a mirror body 12 and a cover 13 having an outer wall surface 14 with a convex surface in its vehicle front side and covering the vehicle front side of the mirror body 12. It is provided with a plurality of protrusions 15 on separation parts (Aa, Ab, Ac) where an air flow Fa flowing along the outer wall surface 14 due to traveling of the vehicle separates from the outer wall surface 14, with predetermined intervals and along the separation parts.

Description

  The present invention relates to an outer mirror device for a vehicle, and more particularly, to an outer mirror device that is attached to a side door, a front pillar, or the like of an automobile and focuses on reducing aerodynamic noise.

  As a vehicle outer mirror device that focuses on reducing aerodynamic noise, the air taken into the air intake provided at the front of the mirror cover is external to the air outlet provided near the parting part between the mirror visor and the mirror cover. What is comprised so that it may be blown out is known (for example, patent document 1).

  In this vehicle outer mirror device, turbulence is generated in the vicinity of the parting part due to the air blown out from the air outlet, and is generated in the vicinity of the parting part by separation of the turbulent flow and the air flow flowing along the outer wall surface of the mirror cover. Interference with the vortex of the generated air prevents the generation of continuous vortices due to separation and suppresses the generation of abnormal noise due to the generation of continuous vortices.

  As another vehicle outer mirror device that focuses on reducing aerodynamic noise, the mirror visor and the mirror cover give up the position where the air flow flowing along the outer wall surface of the mirror cover is separated by devising the shape of the mirror cover. The thing which aimed at reduction of the wind noise generated in the parting part apart from the part is known (for example, patent document 2).

  Further, as an outer mirror device for a vehicle that reduces vibration of a mirror body (mirror main body) caused by Karman vortex, a device in which a bead-shaped protrusion is formed in a vertical direction on a side surface of a mirror cover on the vehicle outer side is known. (For example, patent document 3).

JP 2013-100037 A Japanese Patent No. 4192586 JP-A-10-226276

  However, since the vehicle outer mirror device disclosed in Patent Document 1 blows air from the air outlet to the separation portion of the airflow that flows along the outer wall surface of the mirror cover, depending on the amount of air and the flow velocity. The generation of air vortices is encouraged, and aerodynamic noise may increase.

  The outer mirror device for a vehicle shown in Patent Document 2 does not actively suppress the generation of air vortices due to the separation of the air flow, and a two-dimensional vortex is still generated immediately after the separation. For this reason, noise is generated by the two-dimensional vortex, and further, since the two-dimensional vortex changes to a three-dimensional vortex on the downstream side and dissipates, further noise is generated.

  Even if the outer mirror device for a vehicle shown in Patent Document 3 can suppress the generation of Karman vortices formed behind the mirror body, the protrusion formed on the outer side surface of the mirror cover has a bead shape. Since it is continuous in the vertical direction, a two-dimensional vortex is still generated on the downstream side of the protrusion. For this reason, noise is generated by the two-dimensional vortex, and further, since the two-dimensional vortex changes to a three-dimensional vortex on the downstream side and dissipates, noise due to the three-dimensional vortex is also generated.

  The problem to be solved by the present invention is to effectively reduce aerodynamic noise using the vehicle outer mirror device as a sound source, and to improve the quietness of the vehicle interior.

  The vehicle outer mirror device according to the present invention has a mirror body (12) and a cover (13) having an outer wall surface (14) having a convex curved surface on the front side of the vehicle body and covering the front side of the mirror body (12). And an outer mirror device for a vehicle that is attached to the outside of the vehicle body, wherein an air flow (Fa) that flows along the outer wall surface (14) by the traveling of the vehicle peels from the outer wall surface (14) (Aa, A plurality of protrusions (15) are provided at predetermined intervals along the peeling portions (Aa, Ab, Ac) at or near Ab, Ac).

  According to this configuration, the air flow colliding with the protrusion (15) and the air flow passing between the adjacent protrusions (15) can be alternately seen in the longitudinal direction of the peeling portion (Aa, Ab, Ac), A three-dimensional vortex is generated. As a result, a two-dimensional vortex is not generated immediately after peeling, and the generation of noise is reduced by the amount that the two-dimensional vortex is not generated, thereby improving the quietness in the vehicle.

  In the vehicle outer mirror device according to the present invention, preferably, the outer wall surface (14) includes a ridge line in which a curved surface and a flat surface are connected to form the peeling portion (Aa, Ab, Ac).

  According to this structure, a ridgeline becomes a forced peeling part (Aa, Ab, Ac), and the position of a peeling part (Aa, Ab, Ac) is stabilized.

  In the vehicle outer mirror device according to the present invention, preferably, the height dimension of the protrusion (15) is smaller than the thickness dimension of the boundary layer of the air flow in the vicinity of the peeling portion (Aa, Ab, Ac).

  According to this configuration, since the entire protrusion (15) is in the boundary layer, a new vortex is not generated outside the boundary layer by the protrusion (15), and noise is not increased.

  The vehicle outer mirror device according to the present invention is preferably further provided with an air outlet (opened to the outer wall surface (14) on the upstream side as viewed in the air flow (Fa) from the peeling portion (Aa, Ab, Ac). 16, 18, 20).

  According to this structure, when the air blows out from the air outlet (16, 18, 20) toward the air flow (Fa), the flow velocity of the air flow (Fa) decreases, and the protrusion (15) immediately after the separation causes The amount of 3D vortex generation itself is reduced.

  According to the vehicle outer mirror device of the present invention, the air flow that collides with the protrusions and the air flow that passes between the adjacent protrusions can be alternately viewed in the longitudinal direction of the peeling portion, so that two-dimensionally immediately after peeling. As a result, a three-dimensional vortex is generated without generating a vortex, and a two-dimensional vortex is not generated immediately after separation, so that the generation of noise is reduced and the quietness in the vehicle is improved.

The perspective view of the principal part of the motor vehicle equipped with the outer mirror apparatus for vehicles by this invention. The perspective view which shows Embodiment 1 of the outer mirror apparatus for vehicles by this invention. FIG. 3 is a plan view of the vehicle outer mirror device according to the first embodiment. FIG. 4 is a sectional view taken along line IV-IV in FIG. 3. The graph which shows the relationship between the separation distance from a peeling part to a downstream, and the thickness of a boundary layer. The graph which shows the relationship between the height of a projection part, and a noise reduction effect. The perspective view which shows Embodiment 2 of the outer mirror apparatus for vehicles by this invention. The top view of the outer mirror device for vehicles by this embodiment. Sectional drawing along line IX-IX of FIG. Sectional drawing along line XX of FIG. The graph which shows the average speed of the mainstream direction in each position away from the outer wall surface of the mirror cover in the normal line direction. Explanatory drawing about peeling of the airflow in the column-shaped solid obstacle put in the flow field. The graph which shows the surface pressure coefficient characteristic of the outer wall surface of the cylindrical solid obstacle placed in the flow field.

  Hereinafter, a first embodiment of a vehicle outer mirror device (automobile outside mirror device) according to the present invention will be described with reference to FIGS.

  As shown in FIG. 1, the outside mirror device 10 of an automobile is attached to the front portion of the side door 50 so as to protrude outside the vehicle body by a mounting plate 52. The outside mirror device 10 includes a mirror main body (mirror body) 12 that is a plane mirror or a convex mirror, and a cover 13 that is a resin molded product that covers the front side of the mirror main body 12 in the vehicle body.

  As shown in FIGS. 2 to 4, the cover 13 has an outer wall surface 14 having a convex curved surface on the front side of the vehicle body. The outer wall surface 14 is joined to a wall surface 14A (hereinafter referred to as a partial cylindrical wall surface 14A) formed by a partial cylindrical surface that is long in the lateral direction of the vehicle body and a front end edge of the partial cylindrical wall surface 14A that is farther outward from the vehicle body. A wall surface 14B (hereinafter, referred to as a partial spherical wall surface 14B) that is smoothly continuous with the front end side of the wall surface 14A and a rear side edge of the upper and lower vehicle bodies of the partial cylindrical wall surface 14A are joined to the rear side of the vehicle body from the partial cylindrical wall surface 14A. Upper and lower side wall surfaces 14C and 14D by flat surfaces extending to the side, and a side wall surface 14E by a partial cylindrical surface that is joined to the vehicle body rear side edge of the partial spherical wall surface 14B and extends from the partial spherical wall surface 14B to the vehicle rear side. The partial cylindrical wall surface 14A and the upper and lower side wall surfaces 14C and 14D are constituted by a mounting wall surface 14F formed of a flat surface joined to the inner edges of the vehicle body.

  The cover 13 has a box shape with a rear opening by the wall surfaces 14A to 14F, and the mirror main body 12 is attached to the rear opening. The cover 13 having the wall surfaces 14A to 14F is integrally formed of a synthetic resin or the like as a whole, and includes a connection portion between the partial cylindrical wall surface 14A and the partial spherical wall surface 14B, a connection portion between the side wall surface 14D and the side wall surface 14E, and the side wall surface 14C. There is no parting or seam at the connection with the side wall surface 14E.

  The connecting portion between the partial cylindrical wall surface 14A and the upper and lower side wall surfaces 14C and 14D and the connecting portion between the partial spherical wall surface 14B and the side wall surface 14E are respectively boundary portions (peeling portions) formed by clear ridge lines where the curved surface and the flat surface are connected. ) Aa, Ab, Ac.

  Here, the separation of the air flow in the three-dimensional object (steric obstacle) placed in the flow field will be described with reference to FIG. The surface pressure coefficient Cp of the three-dimensional object W in the flow field is minimized at the separation portion where the air flow flowing along the outer wall surface of the three-dimensional object W does not flow along the outer wall surface on the downstream side. When the three-dimensional object W is a cylindrical body, as shown in FIG. 12, the arc center Wc of the cylindrical wall surface Wf and the foremost point (most upstream point) Wff of the cylindrical wall surface Wf are viewed in one cross section. And the angle inclined to the downstream side of the cylindrical wall surface Wf is θ, the surface pressure coefficient Cp at a site where the angle θ is about 65 to 67 degrees as shown in FIG. Is minimized, and a peeled portion exists at this site. This peeling part is called a natural peeling part.

  The boundary portions Aa, Ab, and Ac of the cover 13 are continuous lines of about 60 degrees smaller than the angle of the natural peeling portion (about 65 to 67 degrees) when viewed at the angle θ by the shape setting of the outer wall surface 14 described above. It exists in the form. That is, the boundary portions Aa, Ab, and Ac are slightly upstream from the natural peeling portion. Thereby, the air flow Fa flowing along the partial cylindrical wall surface 14A or the partial spherical wall surface 14B by traveling of the automobile is separated from the side wall surfaces 14C, 14D, and 14E immediately after passing through the boundary portions Aa, Ab, and Ac. . Since the boundary portions Aa, Ab, and Ac are all formed by clear ridge lines, they form a stable peeling portion that does not change in position. This peeling part is called a forced peeling part. Thus, the forced peeling part of the cover 13 exists in the same position as boundary part Aa, Ab, Ac, and exists linearly over the whole region of boundary part Aa, Ab, Ac.

  A plurality of ½ spherical (semispherical) protrusions 15 are provided on the boundary portions Aa, Ab, and Ac at predetermined intervals in the longitudinal direction of the boundary portions Aa, Ab, and Ac. In other words, the protrusions 15 are formed along the boundary portions Aa, Ab, and Ac, strictly, on the ridge line that forms the boundary portions Aa, Ab, and Ac, or at a predetermined interval on the upstream side adjacent to the ridge line. The protrusion 15 is set to a height that is lower than the boundary layer thickness in the vicinity of the boundary portions Aa, Ab, and Ac and is entirely present in the boundary layer.

  When the automobile travels, the outside mirror device 10 is placed in the air flow field, and the air that collides with the partial cylindrical wall surface 14A or the partial spherical wall surface 14B of the cover 13 becomes the partial cylindrical wall surface 14A as the air flow Fa. Or it flows along the partial spherical wall surface 14B. The air flow Fa flows along the partial cylindrical wall surface 14A or the partial spherical wall surface 14B without being separated until reaching the boundary portions Aa, Ab, and Ac forming the forced separation portion. After the air flow Fa reaches the boundary portions Aa, Ab, and Ac, the air flow Fa does not flow along the side wall surfaces 14C, 14D, and 14E, but becomes a flow separated from the side wall surfaces 14C and 14D.

  The peeled air flow collides with the protrusion 15 almost simultaneously with the peeling. Since the protrusions 15 are provided at predetermined intervals along the boundary portions Aa, Ab, and Ac, the air flow that collides with the protrusions 15 and the air flow that passes between the adjacent protrusions 15 are separated by the boundary portions Aa, It can be seen alternately in the longitudinal direction of Ab and Ac, and a three-dimensional vortex is generated. As a result, a two-dimensional vortex is not generated immediately after peeling, and the generation of noise is reduced by the amount that the two-dimensional vortex is not generated, thereby improving the quietness in the vehicle.

  Since the boundary portions Aa, Ab, and Ac form a stable forced peeling portion that does not change in position due to a clear ridgeline, the positional relationship between the peeling portion and the protrusion 15 does not change, and the action of the protrusion 15 The effect that no dimensional vortex is generated can be obtained stably.

  FIG. 5 shows the relationship between the distance from the peeled portion (boundary portions Aa, Ab, Ac) to the downstream side and the thickness of the boundary layer. As shown by the line D, the boundary layer thickness is about 0.5 mm at the position where the separation distance is zero and about 1.7 mm at the maximum at the position where the separation distance is 2 mm. The condition that the thickness of the protrusion 15 is 2.0 mm or less is that the thickness of the protrusion 15 is lower than the boundary layer thickness in the boundary portions Aa, Ab, and Ac, and the entirety is in the boundary layer.

  FIG. 6 shows the relationship between the height of the protrusion 15 and the amount of noise reduction. Line E indicates the case where the pitch of the protrusions 15 is 4.0 mm, and line F indicates the case where the pitch of the protrusions 15 is 8.0 mm. From FIG. 6, it was found that the noise reduction amount was maximized when the protrusions 15 had a pitch of 4.0 mm and a height of 1.0 mm.

  Next, a second embodiment of a vehicle outer mirror device (automobile outside mirror device) according to the present invention will be described with reference to FIGS. 7 to 10, parts corresponding to those in FIGS. 2 to 4 are denoted by the same reference numerals as those in FIGS. 2 to 4, and description thereof is omitted.

  In the second embodiment, in addition to the protrusion 15, the outer wall surface slightly upstream from the boundary portions Aa, Ab, and Ac, that is, the forced separation portion, as seen by the air flow Fa flowing along the partial cylindrical wall surface 14 </ b> A or the partial spherical wall surface 14 </ b> B. 14, air outlets 16, 18, and 20 are opened. The opening positions of the air outlets 16, 18, and 20 may be an angle (50 degrees) that is about 10 degrees smaller than the angles (60 degrees) of the boundary portions Aa, Ab, and Ac in terms of the aforementioned angle θ.

  The air outlet 16 is formed as a slot-like opening parallel to the boundary Aa over the entire area of the boundary Aa extending linearly above the partial cylindrical wall surface 14A. The air outlet 18 is formed as a slot-like opening parallel to the boundary portion Ab over the entire region of the boundary portion Ab extending linearly below the partial cylindrical wall surface 14A. The air outlet 20 is formed as a slot-like opening extending along the boundary portion Ac at equal intervals over the entire area of the semicircular boundary portion Ac extending to the outer edge of the partial spherical wall surface 14B. . Thereby, the air blower outlets 16, 18, and 20 are extended along the boundary parts Aa, Ab, and Ac as a slot-shaped opening at equal intervals over the whole area of the boundary parts Aa, Ab, and Ac.

  The air outlets 16, 18, and 20 are opened in a normal direction or a direction close to the normal direction with respect to the outer wall surface 14 at each opening position. The air outlets 16, 18, and 20 are slot-shaped openings, but in order to avoid a reduction in the strength of the cover 13 due to the slot-shaped openings, a bridge portion 17 that partially connects both walls of the slot-shaped openings is provided. The cover 13 is integrally formed.

  Air inlets 22, 24, and 26 are opened on the outer wall surface 14 on the upstream side of the air outlet 16 when viewed from the air flow Fa described above.

  The air inlet 22 is formed as a slit-like opening parallel to the air outlet 16 slightly above the central position in the vertical direction of the partial cylindrical wall surface 14A. The air inlet 22 communicates with the air outlet 16 through an air passage 32 defined by a protrusion 28 integrally formed on the back side of the cover 13 and a plate piece 30 bonded to the tip of the protrusion 28. ing.

  The air inlet 24 is formed as a slit-like opening parallel to the air outlet 18 slightly below the central position in the vertical direction of the partial cylindrical wall surface 14A. The air inlet 24 communicates with the air outlet 16 through an air passage 38 defined by a protrusion 34 integrally formed on the back side of the cover 13 and a plate piece 36 bonded to the tip of the protrusion 34. ing.

  The air inlet 26 is formed as a semicircular opening concentric with the air outlet 20 at the center near the portion where the partial spherical wall surface 14B is connected to the partial cylindrical wall surface 14A. The air inlet 26 is connected to the air outlet 20 by a radial air passage 44 defined by a protrusion 40 integrally formed on the back side of the cover 13 and a plate piece 42 bonded to the tip of the protrusion 40. Communicate.

  The air inlets 22, 24, and 26 are open in the normal direction with respect to the outer wall surface 14 at each opening position. That is, the air inlets 22, 24, and 26 are opened toward the front surface of the cover 13 so as to receive the traveling wind.

  In this embodiment, a part of the air colliding with the partial cylindrical wall surface 14A or the partial spherical wall surface 14B of the cover 13 enters the air inlets 22, 24, 26, passes through the air passages 32, 38, 44, and the air outlet 16 , 18 and 20 are blown out toward the air flow Fa outward from the partial cylindrical wall surface 14A or the partial spherical wall surface 14B. The flow velocity of the air flow Fb due to the air blown out from the air outlets 16, 18, and 20 is slower than the flow velocity of the air flow Fa due to the flow path resistance, and this air flow Fb flows upstream of the boundaries Aa, Ab, and Ac. It collides with Fa and merges with the air flow Fa, disturbs the air flow Fa on the upstream side from the boundary A, and lowers the flow velocity of the air flow Fa. This is because the air outlets 16, 18, and 20 are slot-like openings extending along the boundary portions Aa, Ab, and Ac at equal intervals over the entire boundary portions Aa, Ab, and Ac. It occurs over the whole area of the boundary portions Aa, Ab, and Ac.

  Since the opening direction of the air outlets 16, 18, and 20 is a normal direction or a direction close to the normal direction with respect to the outer wall surface 14 at each opening position, the air flow Fb collides with the air flow Fa and the air The degree of disturbance to the flow Fa is increased, and the flow velocity of the air flow Fa is effectively reduced due to the disturbance. If the air flow Fa is excessively disturbed, it may become a new noise generation source. Therefore, new noise may be included in the opening direction of the air outlets 16, 18, 20, the flow rate and the flow velocity of the air flow Fa. There is an optimum value for reducing the flow velocity of the air flow Fa without becoming a source of generation.

  Further, when the air outlets 16, 18, and 20 are opened in the normal direction or a direction close to the normal direction with respect to the outer wall surface 14 at each opening position, the air outlet 16 is caused by the ejector effect by the air flow Fa. , 18 and 20, air is sucked to the outside, and the ejector effect also gives disturbance to the air flow Fa upstream from the boundary portions Aa, Ab, and Ac, and the action of reducing the flow velocity of the air flow Fa is obtained.

  The opening area ratio between each air inlet port 22, 24, 26 and each air outlet port 16, 18, 20 may be about 1: 1, and the air outlet ports 16, 18, 20 depending on the optimum setting of the opening area ratio. The flow rate of the air blown out can be made an optimum value.

  As the flow velocity of the air flow Fa decreases, the flow velocity difference in the main flow direction before and after separation decreases, and the main flow of the air flow Fa with respect to the separation distance in the normal direction from the outer wall surface 14 in the vicinity of the boundary portions Aa, Ab, Ac. As shown by the solid line B in FIG. 11, the air outlets 16, 18, and 20 provided with the average speed in the direction, particularly at the separation distance of 0.2 to 1.4, are provided. Compared to those that are not, the abrupt change in average speed is mitigated.

  As a result, the boundary layer thickness in the vicinity of the boundary portions Aa, Ab, Ac is increased, and the generation amount of the three-dimensional vortex generated by the air flow Fa colliding with the protrusion 15 almost simultaneously with the separation is reduced. Noise generation is further reduced.

  Although the present invention has been described above with reference to preferred embodiments thereof, the present invention is not limited to such embodiments and can be deviated from the spirit of the present invention, as will be readily understood by those skilled in the art. It is possible to change appropriately within the range not to be.

  For example, the protrusion 15 is not limited to a 1/2 sphere, and may have various three-dimensional shapes such as a 1/2 spheroid, a cone, a truncated cone, a cylinder, and a wedge shape. Good.

  In the above-described embodiment, the boundary portions Aa, Ab, and Ac by the ridge lines that form the forced separation portions exist at the connection portions of the partial cylindrical wall surface 14A and the partial spherical wall surface 14B and the side wall surfaces 14C, 14D, and 14E. The connecting portion may have a round shape with a radius of curvature smaller than the radius of curvature of the partial cylindrical wall surface 14A or the partial spherical wall surface 14B. Moreover, the forced peeling part is not essential, and the cover 13 may have any shape that causes peeling, such as a hemispherical shape or a semi-rotating elliptical shape, and the protrusion 15 may be provided on the peeling part. Moreover, the air blower opening opened to the outer wall surface 14 in the upstream from the peeling part should just be provided.

  The supply of air to the air outlets 16, 18, 20 is not limited to the supply from the air inlets 22, 24, 26 formed in the cover 13, and may be supplied from other air sources. The air outlets 16, 18, and 20 need only be provided along the boundary portions Aa, Ab, and Ac, and may be intermittently opened instead of the continuous slot-like openings.

  In addition, all the components shown in the above embodiment are not necessarily essential, and can be appropriately selected without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 10 Outside mirror apparatus 12 Mirror main body 13 Cover 14 Outer wall surface 14A Partial cylindrical wall surface 14B Partial spherical wall surface 14C Side wall surface 14D Side wall surface 14E Side wall surface 14F Mounting wall surface 15 Projection 16 Air blower outlet 18 Air blower outlet 20 Air blower outlet 22 Air introduction Port 24 Air introduction port 26 Air introduction port 32 Air passage 38 Air passage 44 Air passage 50 Side door Aa boundary portion Ab boundary portion Ac boundary portion

Claims (4)

A vehicle outer mirror device that has a mirror body and a cover that has an outer wall surface with a convex curved surface on the front side of the vehicle body and covers the vehicle body front side of the mirror body, and is attached to the outside of the vehicle body,
The cover has a peeling portion from which an air flow flowing along the outer wall surface is peeled from the outer wall surface by traveling of the vehicle,
A vehicle outer mirror device in which a plurality of protrusions are provided at predetermined intervals along or along the peeling portion at or near the peeling portion.   2. The vehicle outer mirror device according to claim 1, wherein the outer wall surface includes a ridge line in which a curved surface and a flat surface are connected to form the peeling portion.   3. The vehicle outer mirror device according to claim 1, wherein a height dimension of the protrusion is smaller than a thickness dimension of an air flow boundary layer in the vicinity of the peeling portion.   The vehicle outer mirror device according to any one of claims 1 to 3, further comprising an air outlet opening in the outer wall surface on the upstream side as viewed in the air flow from the peeling portion.

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