BACK DOOR STRUCTURE OF VEHICLE

Abstract

A back door structure of a vehicle capable of reducing noise in a vehicle interior by suppressing vibration of an outer panel while reducing the weight and costs includes an outer panel and an inner panel. The inner panel includes a horizontal frame part, side-direction frame parts, and connecting parts. The horizontal frame part and each of the side-direction frame parts are mutually connected. The connecting part extends only from one end part on an opening part side in a vertical width direction of the horizontal frame part, the connecting part extends only from one end part on an opening part side in the vertical width direction of the side-direction frame part, and the connecting part extends only from one end part on an opening part side in the vertical width direction of the side-direction frame part. The connecting parts are respectively connected to the outer panel.

Claims

1. A back door structure of a vehicle that includes a windshield opening part to which a windshield is fitted, comprising: an outer panel forming an outer side of the vehicle in the back door; an inner panel forming an inner side of the vehicle in the back door; and a plurality of connecting parts connecting the outer panel and the inner panel, wherein the inner panel includes a first opening part provided above a lower end side of the inner panel in a lower portion than the windshield opening part, a second opening part provided between the first opening part and the windshield opening part, a third opening part provided between the first and second opening part and a right end side of the inner panel, a fourth opening part provided between the first and second opening part and a left end side of the inner panel, a first side-direction frame part extending between the second opening part and the third opening part in an up and down direction and provided to be inclined so as to approach the side of the right end side as going from a lower end to an upper end, a second side-direction frame part extending between the second opening part and the fourth opening part in the up and down direction and provided to be inclined so as to approach the side of the left end side as going from a lower end to an upper end, and a horizontal frame part extending between the first opening part and the second opening part in a right and left direction and provided so that a right end is connected to the lower end of the first side-direction frame part and a left end is connected to the lower end of the second side-direction frame part, and the plurality of connecting part includes a first connecting part connecting only one end part in a vertical width direction of the horizontal frame part to the outer panel, a second connecting part connecting only one end part in the vertical width direction of the first side-direction frame part to the outer panel, and a third connecting part connecting only one end part in the vertical width direction of the second side-direction frame part to the outer panel.

2. The back door structure of the vehicle according to claim 1, wherein the first connecting part, the second connecting part, and the third connecting part are provided so as to overlap one another in side view from the right and left direction.

3. The back door structure of the vehicle according to claim 2, wherein the second connecting part and the third connecting part are arranged in a symmetrical positional relationship based on the first connecting part.

4. The back door structure of the vehicle according to claim 2, wherein the first connecting part includes a connecting wall part connecting between the outer panel and the inner panel in a front and rear direction, and the connecting wall part has beads formed so as to extend in the front and rear direction.

5. The back door structure of the vehicle according to claim 2, wherein the first connecting part is integrally formed with the horizontal frame part, the second connecting part is integrally formed with the first side-direction frame part, and the third connecting part is integrally formed with the second side-direction frame part.

6. The back door structure of the vehicle according to claim 2, wherein the inner panel further includes a first vertical frame part extending between the first opening part and the third opening part in the up and down direction and provided so that an upper end is connected to the lower end of the first side-direction frame part and the right end of the horizontal frame part, a second vertical frame part extending between the first opening part and the fourth opening part in the up and down direction and provided so that an upper end is connected to the lower end of the second side-direction frame part and the left end of the horizontal frame part, a first merging part provided at a portion where the first vertical frame part, the first side-direction frame part, and the horizontal frame part merge, and a second merging part provided at a portion where the second vertical frame part, the second side-direction frame part, and the horizontal frame part merge, wherein the first side-direction frame part is arranged so that an angle made by the first side-direction frame part with an axis line extending along the up and down direction of the back door is larger than an angle made by the first vertical frame part, and wherein the second side-direction frame part is arranged so that an angle made by the second side-direction frame part with an axis line extending along the up and down direction of the back door is larger than an angle made by the second vertical frame part.

7. The back door structure of the vehicle according to claim 6, wherein each of the first merging part and the second merging part has an approximately triangular shape in front view.

8. The back door structure of the vehicle according to claim 2, wherein the first connecting part connects only one end part on the first opening part's side in the vertical width direction of the horizontal frame part to the outer panel, the second connecting part connects only one end part on the third opening part's side in the vertical width direction of the first side-direction frame part to the outer panel, and the third connecting part connects only one end part on the fourth opening part's side in the vertical width direction of the second side-direction frame part to the outer panel.

9. The back door structure of the vehicle according to claim 1, wherein the second connecting part and the third connecting part are arranged in a symmetrical positional relationship based on the first connecting part.

10. The back door structure of the vehicle according to claim 1, wherein the first connecting part includes a connecting wall part connecting between the outer panel and the inner panel in a front and rear direction, and the connecting wall part has beads formed so as to extend in the front and rear direction.

11. The back door structure of the vehicle according to claim 1, wherein the first connecting part is integrally formed with the horizontal frame part, the second connecting part is integrally formed with the first side-direction frame part, and the third connecting part is integrally formed with the second side-direction frame part.

12. The back door structure of the vehicle according to claim 1, wherein the inner panel further includes a first vertical frame part extending between the first opening part and the third opening part in the up and down direction and provided so that an upper end is connected to the lower end of the first side-direction frame part and the right end of the horizontal frame part, a second vertical frame part extending between the first opening part and the fourth opening part in the up and down direction and provided so that an upper end is connected to the lower end of the second side-direction frame part and the left end of the horizontal frame part, a first merging part provided at a portion where the first vertical frame part, the first side-direction frame part, and the horizontal frame part merge, and a second merging part provided at a portion where the second vertical frame part, the second side-direction frame part, and the horizontal frame part merge, wherein the first side-direction frame part is arranged so that an angle made by the first side-direction frame part with an axis line extending along the up and down direction of the back door is larger than an angle made by the first vertical frame part, and wherein the second side-direction frame part is arranged so that an angle made by the second side-direction frame part with an axis line extending along the up and down direction of the back door is larger than an angle made by the second vertical frame part.

13. The back door structure of the vehicle according to claim 12, wherein each of the first merging part and the second merging part has an approximately triangular shape in front view.

14. The back door structure of the vehicle according to claim 1, wherein the first connecting part connects only one end part on the first opening part's side in the vertical width direction of the horizontal frame part to the outer panel, the second connecting part connects only one end part on the third opening part's side in the vertical width direction of the first side-direction frame part to the outer panel, and the third connecting part connects only one end part on the fourth opening part's side in the vertical width direction of the second side-direction frame part to the outer panel.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0038] FIG. 1 is a rear view of a back door according to an embodiment, which is seen from a rear direction of a vehicle.

[0039] FIG. 2 is a front view of the back door seen from the front of the vehicle.

[0040] FIG. 3 is an enlarged view showing a A-part of FIG. 2 in an enlarged manner.

[0041] FIG. 4 is a perspective view showing a structure of a central connecting part.

[0042] FIG. 5A is a front view showing a horizontal frame part, side-direction frame parts, and a peripheral structure thereof.

[0043] FIG. 5B is a graph showing displacement in 3-order resonance of an outer panel when assuming that the an inner panel is not connected.

DETAILED DESCRIPTION

[0044] Hereinafter, an embodiment of the present disclosure will be explained with reference to the drawings. Note that the description explained below is not at all limited to the following embodiment except its essential structure.

1. Entire Structure of Back Door 1

[0045] The entire structure of a back door 1 of a vehicle according to the embodiment will be explained with reference to FIG. 1 and FIG. 2. In the specification, directions are indicated on the basis of the vehicle to which the back door 1 is mounted. Specifically, an upper direction of the vehicle is denoted as “UP”, a lower direction of the vehicle is denoted as “LO”, a left direction of the vehicle is denoted as “LH”, and a right direction of the vehicle is denoted as “RH”. The direction of the back door 1 is indicated on the basis of the back door 1 in a state where a rear opening of the vehicle is closed.

[0046] As shown in FIG. 1 and FIG. 2, the back door 1 has a windshield opening part 1a to which a windshield is fitted at an upper half part. The back door 1 includes an outer panel 10 and an inner panel 11. The outer panel 10 is a panel forming an outer side of the back door 1. The inner panel 11 is a panel forming an inner side than the outer panel 10 in the back door 1.

[0047] An area where a number plate is assumed to be fitted (plate fitting area) 1b is provided at a lower part in a lower half of the back door 1. The plate fitting area 1b is prescribed in consideration of destinations of vehicles to which the back door 1 is applied.

[0048] As shown in FIG. 2, four opening parts SP1 to SP4 are provided in the inner panel 11. The opening part (first opening part) SP1 is provided at the central portion in vehicle width direction (right and left direction) of the back door 1 so as to be apart from a lower end side of the inner panel 11. The opening part (second opening part) SP4 is provided between the opening part SP1 and the windshield opening part 1a in an up and down direction of the back door 1 so as to be apart respectively from the opening part SP1 and the windshield opening part 1a. A horizontal width (width in the right and left direction) of the opening part SP4 is set to be wider than the opening part SP1.

[0049] The opening part (third opening part) SP2 is provided between the opening part SP1/the opening part SP4 and a right end side of the inner panel 11 so as to be apart respectively from the opening parts SP1, SP4, and the right end side of the inner panel 11. The opening part SP2 has an approximately triangular shape with rounded corners in front view from the front direction of the vehicle. The opening (fourth opening part) SP3 is provided between the opening part SP1/the opening part SP4 and a left end side of the inner panel 11 so as to be apart respectively from the opening parts SP1, SP4, and the left end side of the inner panel 11. The opening part SP3 has an approximately triangular shape with rounded corners that is symmetrical to the opening part SP2 in front view seen from the front direction of the vehicle.

[0050] Moreover, as shown in FIG. 2, the inner panel 11 has outer peripheral frame parts 11a to 11d, side-direction frame parts 11e, 11f, vertical frame parts 11m, 11n, and a horizontal frame part 11g. The lower outer peripheral frame part 11a among the outer peripheral frame parts 11a to 11d is a frame part extending between the opening parts SP1/SP2/SP3 and the lower end side of the inner panel 11 in the right and left direction. The side outer peripheral frame part lib is a frame part extending between the opening part SP3 and the left end side of the inner panel 11 in the up and down direction. The lower outer peripheral frame part 11a and the side outer peripheral frame part lib are connected to each other at an abutting portion. The side outer peripheral frame part 11c is a frame part extending between the opening part SP2 and the right end side of the inner panel 11 in the up and down direction. The lower outer peripheral frame part 11a and the side outer peripheral frame part 11c are connected at an abutting portion therebetween. The upper outer peripheral frame part 11d is a frame part extending between the opening parts SP4/SP2/SP3 and the windshield opening part 1a in the right and left direction. The side outer peripheral frame part 11b, the side outer peripheral frame part 11c, and the upper outer peripheral frame part 11d are connected at abutting portions therebetween.

[0051] The side-direction frame part (first side-direction frame part) 11e is a frame part extending between the opening part SP4 and the opening part SP2 in the up and down direction. The side-direction frame part 11e is provided to be inclined so as to gradually come close to the side outer peripheral frame part 11c side (side of the right end side of the inner panel 11) as going from a lower end to an upper end. The side-direction frame part 11e is connected to the side outer peripheral frame part 11c and the upper outer peripheral frame part 11d at the upper end.

[0052] The side-direction frame part (second side-direction frame part) 11f is a frame part extending between the opening part SP4 and the opening part SP3 in the up and down direction. The side-direction frame part 11f is provided to be inclined so as to gradually come close to the side outer peripheral frame part lib side (side of the left end side of the inner panel 11) as going from a lower end to an upper end. The side-direction frame part 11f is connected to the side outer peripheral frame part 11b and the upper outer peripheral frame part 11d at the upper end.

[0053] The horizontal frame part 11g is a frame part extending between the opening part SP1 and the opening part SP4 in the right and left direction. The horizontal frame part 11g is connected to the lower end of the side-direction frame part 11e at a right end and is connected to the lower end of the side-direction frame part 11f at a left end.

[0054] Here, the horizontal frame part 11g is connected to the side-direction frame part 11e at the right end and connected to the side-direction frame part 11f at the left end as described above. Therefore, when these frame parts 11e to 11g are seen as a whole, these parts can be regarded as one frame part extending in the right and left direction.

[0055] The vertical frame part (first vertical frame part) 11m is a frame part extending in the up and down direction between the opening part SP1 and the opening part SP2. The vertical frame part 11m is connected to the lower outer peripheral frame part 11a at a lower end and is connected to the lower end of the side-direction frame part 11e and the right end of the horizontal frame part 11g at an upper end. The vertical frame part (second frame part) 11n is a frame part extending in the up and down direction between the opening part SP1 and the opening part SP3. The vertical frame part 11n is connected to the lower outer peripheral frame part 11a at a lower end and is connected to the lower end of the side-direction frame part 11f and the right end of the horizontal frame part 11g at an upper end.

[0056] In the inner panel 11, a portion where the side-direction frame part 11e, the horizontal frame part 11g, and the vertical frame part 11m are connected (portion where these parts merge) is defined as a merging part (first merging part) 11h, and a portion where the side-direction frame part 11f, the horizontal frame part 11g, and the vertical frame part 11n are connected (portion where these parts merge) is defined as a merging part (second merging part) 11i. Note that the merging part 11h and the merging part 11i are formed in symmetrical shapes in the embodiment.

[0057] As shown in FIG. 2, the inner panel 11 further includes three connecting parts 11j to 11l. The central connecting part (first connecting part) 11j among the three connecting parts 11j to 11l is integrally formed with the horizontal frame part 11g. The side connecting part (second connecting part) 11k is integrally formed with the side-direction frame part 11e. The side connecting part (third connecting part) 11l is integrally formed with the side-direction frame part 11f.

[0058] The central connecting part 11j connects the horizontal frame part 11g and the outer panel 10 at a central portion in the right and left direction of the back door 1. The side connecting part 11k connects the side-direction frame part 11e and the outer panel 10 at a right portion of the back door. The side connecting part 11l connects the side-direction frame part 11f and the outer panel 10 at a left portion of the back door 1.

2. Detailed Structure of Merging Parts 11h, 11i in Inner Panel 11 and Peripheral Area Thereof

[0059] The detailed structure of the merging parts 11h, 11i in the inner panel 11 and a peripheral area thereof will be explained with reference to FIG. 3.

[0060] As shown in FIG. 3, the merging part 11h is provided at an area surrounded by the opening part SP1, the opening part SP2, and the opening part SP4, and the merging part 11i is provided at an area surrounded by the opening part SP1, the opening part SP3, and the opening part SP4. Accordingly, each of the merging parts 11h, 11i has an approximately triangular shape in which a width in the right and left direction gradually increases as going from the lower part to the upper part. Although each of the merging parts 11h, iii is shown as the triangular shape with rounded corners in FIG. 3, it is possible to prescribe each merging part as a triangular shape (precisely, a hexagonal shape) with respective corners cut in straight lines.

[0061] In the back door 1 according to the embodiment, the side-direction frame part 11e and the vertical frame part 11m are provided so that extending angles thereof differ from each other. Specifically, when a center line of the vertical frame part 11m is Lm, and a center line of the side-direction frame part 11e is Le, angles θ1, θ2 made by the center lines and reference lines Lv1, Lv2 extending along the up and down direction of the back door 1 are set so as to satisfy the following relation.

θ2>θ1  (formula 1)

[0062] The side-direction frame part 11f and the vertical frame part 11n on the left side are also provided so that these angles differ from each other.

[0063] In the back door 1 according to the embodiment, each of the side-direction frame parts 11e, 11f is formed so as to have a larger inclination angle than each of the vertical frame parts 11m 11n in the inner panel 11.

[0064] The side-direction frame part 11e and the side-direction frame part 11f are formed in a symmetrical relationship, and the vertical frame part 11m and the vertical frame part 11n are also formed in the symmetrical relationship.

3. Detailed Structure of Connecting Parts 11j to 11l

[0065] The detailed structure of the connecting parts 11j to 11l in the inner panel 11 will be explained with reference to FIG. 3.

[0066] As shown in FIG. 3, the central connecting part 11j is extended only from one end part on the opening part SP1 side in a vertical width direction of the horizontal frame part 11g, extending toward the outer panel 10 arranged on the rear side of the vehicle (toward the back side of the paper in FIG. 3) and being connected to the outer panel 10 at the end part. The side connecting part 11k is extended only from one end part on the opening part SP2 side in the vertical width direction of the side-direction frame part 11e, extending toward the outer panel 10 arranged on the rear side of the vehicle (toward the back side of the paper in FIG. 3) and being connected to the outer panel 10 at the end part. The side connecting part 11l is extended only from one end part on the opening part SP3 side in the vertical width direction of the side-direction frame part 11f, extending toward the outer panel 10 arranged on the rear side of the vehicle (toward the back side of the paper in FIG. 3) and being connected to the outer panel 10 at the end part.

[0067] The side connecting part 11k and the side connecting part 11l are arranged at symmetrical positions on the basis of the central connecting part 11j in the right and left direction. In other words, the central connecting part 11j is arranged at the middle position between the side connecting part 11k and the side connecting part 11l in the right and left direction.

[0068] When the central connecting part 11j and the side connecting parts 11k, 11l are seen from the side in the right and left direction, the connecting parts 11j to 11l are arranged in a positional relationship of overlapping one another. The connecting parts 11j to 11l are arranged in an area containing the plate fitting area 1b in the up and down direction.

[0069] Note that an extending portion of the central connecting part 11j with respect to the horizontal frame part 11g, an extending portion of the side connecting part 11k with respect to the side-direction frame part 11e, and an extending portion of the side connecting part 11l with respect to the side-direction frame part 11f are aligned at one end parts in the vertical width direction of respective frame parts 11e to 11g. That is, one end part on the lower side in the vertical width direction of the horizontal frame part 11g is connected to the outer panel 10 by the central connecting part 11j, one end part on the lower side in the vertical width direction of the side-direction frame part 11e is connected to the outer panel 10 by the side connecting part 11k, and one end part on the lower side in the vertical width direction of the side-direction frame part 11f is connected to the outer panel 10 by the side connecting part 11l in the embodiment.

4. Structure of Central Connecting Part 11j

[0070] The structure of the central connection part 11j extended from one end part in the width direction of the horizontal frame part 11g will be explained with reference to FIG. 4.

[0071] As shown in FIG. 4, an outer joining part llj1, an inner bending part 11j2, and a standing wall part (connecting wall part) 11j3 are continuously formed in the central connecting part 11j. The outer joining part llj1 is a part joined to the outer panel 10. Joining between the outer joining part llj1 and the outer panel 10 is made, for example, by spot welding or by using an adhesive.

[0072] The inner bending part 11j2 is a part having an L-shape in cross section extending from one end part in the width direction of the horizontal frame part 11g and bent toward the outer panel 10. The standing wall part 11j3 is a wall part connecting between the outer joining part llj1 and the inner bending part 11j2, which is formed so as to extend in a front and rear direction of the vehicle and in the vehicle width direction.

[0073] As shown in FIG. 4, a plurality of beads 11j4 are formed on the standing wall part j3 of the central connecting part 11j. The plurality of beads 11j4 are formed so as to respectively extend in the front and rear direction and so as to be aligned in the right and left direction (vehicle width direction).

[0074] Suppression of Film Surface Resonance of Outer Panel 10 in Back Door 1

[0075] A mechanism for suppressing the film surface resonance of the outer panel 10 in the back door 1 according to the embodiment will be explained with reference to FIGS. 5A and 5B. FIG. 5B is a graph for showing displacement in the film surface resonance (3-order resonance) of the outer panel 10 occurring during traveling of the vehicle when assuming that the frame parts 11e to 11g in the inner panel 11 are not connected to the outer panel 10.

[0076] As shown in FIG. 5A, a width-direction central portion 10a where the central connecting part 11j is connected may be displaced so as to float to the front side, and respective width-direction side portions 10b, 10c where the side connecting parts 11k, 11l are connected may be displaced to the rear side in the outer panel 10 during traveling of the vehicle. That is, when assuming that the frame parts 11e to 11g of the inner panel 11 are not connected to the outer panel 10, a line L5 in which an area containing a portion indicated by a virtual line L1 is displaced to the front side as shown by an arrow B4 and areas containing portions indicated by virtual lines L2, L3 are displaced to the rear side as shown by arrows B5, B6 is made with respect to a line L4 of the outer panel 10 before displacement as shown in FIG. 5B.

[0077] Even when the 3-order resonance of the outer panel 10 is about to occur during traveling of the vehicle, the frame parts 11e to 11g of the inner panel 11 are connected to the outer panel 10 through the three connecting parts 11j to 11l in the back door 1 according to the embodiment; therefore, the 3-order resonance of the outer panel 10 is suppressed. Specifically, when the outer panel 10 is about to vibrate as described above, the torsional moment indicated by an arrow B1 acts on the horizontal frame part 11g by the input through the central connecting part 11j, the torsional moment indicated by an arrow B2 acts on the side-direction frame part 11e by the input through the side connecting part 11k, and the torsional moment indicated by an arrow B3 acts on the side-direction frame part 11f by the input through the side connecting part 11l. Since each of the side-direction frame parts 11e, 11f and the horizontal frame part 11g are formed so as to be connected at the merging parts 11h, 11i, the torsional moment indicated by the arrow B1 is cancelled out by the torsional moments indicated by the arrows B2, B3.

[0078] The horizontal frame part 11g is connected to the side-direction frame part 11e at the right end, and is connected to the side-direction frame part 11f at the left end as described above. Accordingly, when these frame parts 11e to 11g are seen as a whole, these parts can be regarded as one frame part extending in the right and left direction. The extending portion of the central connecting part 11j with respect to the horizontal frame part 11g, the extending portion of the side connecting part 11k with respect to the side-direction frame part 11e, and the extending portion of the side connecting part 11l with respect to the side-direction frame part 11f are aligned on one side in the vertical width direction of respective frame parts 11e to 11g in the embodiment.

[0079] Therefore, the film surface resonance of the outer panel 10 during traveling of the vehicle can be suppressed in the back door 1 according to the embodiment.

6. Advantages

[0080] In the back door 1 of the vehicle according to the embodiment, the central connecting part 11j connects only one end part in the vertical width direction of the horizontal frame part 11g and the outer panel 10, the side connecting part 11k connects only one end part in the vertical width direction of the side-direction frame part 11e and the outer panel 10, and the side connecting part 11l connects only one end part in the vertical width direction of the side-direction frame part 11f and the outer panel 10; therefore, the formation number of the connecting parts 11j to 11l can be reduced as compared with a structure in which both end parts in the vertical width direction of each of the frame parts 11e to 11g are connected to the outer panel 10, which can reduce the weight and costs.

[0081] When only one end part in the vertical width direction of each of the frame parts 11e to 11g is connected to the outer panel 10 by the connecting parts 11j to 11l as in the embodiment, torsion may occur (the torsional moment occurs) in the respective frame parts 11e to 11g around axial centers extending in the longitudinal direction due to vibration inputted from the outer panel 10. In this case, when the 3-order resonance is about to occur, behaviors of opposite phases in the front and rear direction may occur at the portion where the central connecting part 11j is connected (the horizontal frame part 11g) and the portions where the side connecting parts 11k, 11l are respectively connected (the side-direction frame parts 11e, 11f) in the outer panel 10.

[0082] However, the central connecting part 11j is connected to the horizontal frame part 11g of the inner panel 11, the side connecting part 11k is connected to the side-direction frame part 11e of the inner panel 11, and the side connecting part 11l is connected to the side-direction frame part 11f in the back door 1; therefore, the torsional moment of the horizontal frame part 11g due to vibration inputted from the outer panel 10 to the horizontal frame part 11g through the central connecting part 11j is cancelled out by the torsional moments occurring at the side-direction frame parts 11e, 11f due to vibration inputted from the outer panel 10 to the side-direction frame part 11e through the side connecting part 11k, and vibration inputted from the outer panel 10 to the side-direction frame part 11f through the side connecting part 11l.

[0083] Accordingly, the outer panel 10 and the inner panel 11 are connected by the three connecting parts 11k to 11l while reducing the weight and costs, thereby suppressing vibration at the outer panel 10 during traveling of the vehicle and reducing noise in the vehicle interior in the back door 1 of the vehicle according to the embodiment.

[0084] Moreover, the central connecting part 11j and the side connecting parts 11k, 11l are provided so as to overlap one another in side view from the right and left direction in the back door 1 of the vehicle according to the embodiment; therefore, the back door 1 of the vehicle has an advantage in suppressing the film surface resonance of the outer panel 10 by the inner panel 11 without complicating a resonance mode of the outer panel 10.

[0085] In the back door 1 of the vehicle according to the embodiment, the side connecting part 11k and the side connecting part 11l are formed in the symmetrical positional relationship on the basis of the central connecting part 11j, in other words, the central connecting part 11j is arranged at an approximately middle position between the side connecting part 11k and the side connecting part 11l in the right and left direction (vehicle width direction); therefore, the torsional moment acting on the horizontal frame part by the input from the outer panel 10 through the central connecting part 11j can be effectively cancelled out by respective torsional moments acting on the side-direction frame parts 11e, 11f by the input from the outer panel in the same manner through the respective side connecting parts 11k, 11l.

[0086] Moreover, the back door 1 of the vehicle according to the embodiment is provided with the beads 11j4 on the standing wall part 11j3 in the central connecting part 11j; therefore, high rigidity of the standing wall part 11j3 can be secured with respect to vibration inputted from the outer panel 10 to the inner panel 11. Accordingly, it is further effective to suppress the film surface resonance of the outer panel 10 by the inner panel 11.

[0087] Moreover, the central connecting part 11j is integrally formed with the horizonal frame part 11g, the side connecting part 11k is integrally formed with the side-direction frame part 11e, and the side connecting part 11l is integrally formed with the side-direction frame part 11f, respectively in the back door 1 of the vehicle according to the embodiment; therefore, the number of parts can be reduced. Furthermore, connection between the central connecting part 11j and the horizontal frame part 11g, connection between the side connecting part 11k and the side-direction frame part 11e, and connection between the side connecting part 11l and the side-direction frame part 11f are not necessary, which can reduce man-hours at the time of manufacturing. Accordingly, the back door 1 of the vehicle according to the embodiment further has an advantage in reducing the weight and costs.

[0088] Moreover, the side-direction frame part 11e extends outward (to the right side in the right and left direction) as going from the lower side to the upper side at a larger angle than the vertical frame part 11m, and the side-direction frame part 11f extends outward (to the left side in the right and left direction) as going from the lower side to the upper side at a larger angle than the vertical frame part 11n in the back door 1 of the vehicle according to the embodiment; therefore, a large dimension in the right and left direction (vehicle width direction) can be taken in each of the merging parts 11h, 11i as compared with a case where both of the side-direction frame part 11e and the vertical frame part 11m are formed along one straight line and both of the side-direction frame part 11f and the vertical frame part 11n are formed along one straight line. Accordingly, cancellation of the torsional moment between the horizontal frame part 11g and the side-direction frame part 11e through the merging part 11h, and cancellation of the torsional moment between the horizontal frame part 11g and the side-direction frame part 11f through the merging part iii can be positively executed in the back door 1.

[0089] Moreover, the back door 1 of the vehicle according to the embodiment has an advantage in dispersing loads inputted from the outer panel 10 to the inner panel 11 through the respective connecting parts 11j to 11l as each of the merging parts 11h, iii has the approximately triangular shape in front view.

[0090] Furthermore, in the back door 1 of the vehicle according to the embodiment, the central connecting part 11j is arranged at one end part on the opening part SP1 side in the vertical width direction of the horizontal frame part 11g, the side connecting part 11k is arranged at one end part on the opening part SP2 side in the vertical width direction of the side-direction frame part 11e, and the side connecting part 11l is arranged at one end part on the opening part SP3 side in the vertical width direction of the side-direction frame part 11f; therefore, the plate fitting area 1b and peripheral areas thereof on the outer panel 10 can be connected to the inner panel 11 by the connecting parts 11j to 11l. Accordingly, the plate fitting area 1b where the film surface resonance tends to occur on the outer panel 10 is connected to the inner panel 11, thereby further exhibiting an advantage in suppressing the film surface resonance.

[0091] As described above, it is possible to reduce noise in the vehicle interior by suppressing vibration of the outer panel 10 while reducing the weight and costs in the back door 1 of the vehicle according to the embodiment.

Modification Examples

[0092] The three connecting parts 11j to 11l are arranged so as to overlap one another when the three connecting parts 11j to 11l are seen from the side in the right and left direction in the above embodiment; however, it is not always necessary that the three connecting parts overlap one another in the present disclosure.

[0093] The structure in which the side connecting part 11k and the side connecting part 11l are arranged at symmetrical positions in front view from the front and rear direction, and the central connecting part 11j is arranged at a middle portion between the side connecting parts 11k, 11l is adopted in the above embodiment; however, it is not always necessary that the side connecting parts are arranged in the symmetrical positional relationship and it is not always necessary that the central connecting part is arranged at the middle portion between the side connecting parts in the present disclosure.

[0094] The structure in which the beads 11j4 are formed on the standing wall part 11j3 of the central connecting part 11j is adopted in the above embodiment; however, a structure in which beads are formed on standing wall parts (connecting wall parts) of all connecting parts can be adopted and a structure in which any bead is not formed on each of standing wall parts of all connecting parts can be also adopted.

[0095] The structure in which the connecting part 11j to 11l are integrally formed with the frame parts 11e to 11g of the inner panel 11 is adopted in the above embodiment; however, it is possible to adopt a structure in which connecting parts are separated from the inner panel in the present disclosure.

[0096] Moreover, the structure in which the central connecting part 11j extends to the opening part SP1 side, the side connecting part 11k extends to the opening part SP2 side, and the side connecting part 11l extends to the opening part SP3 side is adopted in the above embodiment; however, the present disclosure is not limited to this. For example, a structure in which the central connecting part and the side connecting parts respectively extend to the opening part SP4 side can be adopted.

[0097] The structure in which extending angles of the side-direction frame part 11e and the vertical frame part 11m differ from each other and extending angles of the side-direction frame part 11f and the vertical frame part 11n differ from each other is adopted in the above embodiment; however, it is possible to adopt a structure in which the side-direction frame part and the vertical frame part are placed on one straight line in the present disclosure.

[0098] The structure in which the inner panel 11 includes the outer peripheral frame parts 11a to 11d is adopted in the above embodiment; however, it is not always necessary that the inner panel includes the outer peripheral frame parts.

[0099] Moreover, the structure in which one end part on the lower side in the vertical width direction of the horizontal frame part 11g and the outer panel 10 are connected by the central connecting part 11j, one end part on the lower side in the vertical width direction of the side-direction frame part 11e and the outer panel 10 are connected by the side connecting part 11k, and one end part on the lower side in the vertical width direction of the side-direction frame part 11f and the outer panel 10 are connected by the side connecting part 11l is adopted in the above embodiment; however, the present disclosure is not limited to this. For example, a structure in which one end part on the upper side in the vertical width direction of the horizontal frame part and the outer panel are connected by the central connecting part, and one end parts on the upper side in the vertical width direction of respective side-direction frame parts and the outer panel are connected by right-and-left both sides of side connecting parts can be adopted. The same advantages as the above embodiment can be obtained also in the case where respective connecting parts are arranged in this manner.