JP3493679B2 - Car back door mounting structure - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for mounting a back door of an automobile. 2. Description of the Related Art As a structure for mounting a back door of an automobile, a back door frame located above a back door glass is formed in a structure having a closed sectional space defined by an outer panel and an inner panel. Japanese Patent Application Laid-Open No. Sho 62-175216 proposes an arrangement in which a reinforcing reinforcement is disposed in a closed section space to increase rigidity. [0003] A simple way to prevent backdoor resonance, which can occur when an automobile is traveling at high speed, is to increase the backdoor resonance frequency. Since the resonance frequency is proportional to the square root of the ratio of the second moment of area to the mass, to increase the resonance frequency,
Reduce the mass of the back door or reduce the rigidity (section 2
Next moment) may be increased. However, when the reinforcement is arranged over the entire length of the back door frame as in the proposed mounting structure, the rigidity of the back door and the weight increase, so that it is difficult to increase the resonance frequency. [0004] Further, as the weight of the back door increases, it is necessary to increase the ability of the cylinder device arranged to push the back door open. However, the reaction force applied to the back door is increased, and the back door is increased. The deformation of itself will occur. An object of the present invention is to provide a mounting structure for a back door of an automobile, which can increase rigidity while suppressing weight increase. According to the present invention, a back door having a back door upper as a mounting portion having a closed sectional space defined by an outer panel and an inner panel is defined by the upper panel and the lower panel. A closed cross-sectional space, and attached to a rear header provided at the upper end of an opening for the back door of the vehicle body by two hinges spaced apart in the lateral direction of the vehicle body, wherein the mounting portion of the back door is , comprising a bulkhead for reinforcement within the spacing between said hinge dividing the closed section space, the bulkhead is formed by protruding a central portion of the plate from <br/> peripheral portion surrounding this, the protrusion By
A vertical wall is provided between the two parts . The vertical load applied to the back door from the suspension and the reaction force of the cylinder device are received by the large rigidity of the bulkhead. The bulkhead is formed from a flat plate and has a small weight gain due to its size in the range of the distance between the two hinges, while the bulkhead projects a central portion of the flat plate from a peripheral portion surrounding it. This
Since the vertical wall is provided between the two portions , great rigidity can be obtained. As a result, the resonance frequency of the back door can be increased, and the resonance can be suppressed. Since the weight increase due to the bulkhead is small,
Even if the capacity of the cylinder device is increased, a small increase in the capacity is sufficient, but the large rigidity provided by the bulkhead can easily receive the reaction force of the cylinder device and prevent the back door itself from being deformed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIGS. 1 and 3, the present invention has a structure in which a back door 10 is attached to an opening 14 for the back door 10 of a vehicle body 12. As shown in FIG. The back door 10 has a back door upper 16 as a mounting portion, while the opening 1
A rear header 18 is provided at the upper end of the fourth. The back door upper 16 and the rear header 18 include a bulkhead 20 and a bulkhead 22 for reinforcement , respectively . The back door 10 has a structure known per se, and the back door upper 16 has a closed section space 28 defined by an outer panel 24 and an inner panel 26.
Having. The back door glass 30 is attached below the back door upper 16. On the other hand, the rear header 18 has a closed section space 36 defined by the upper panel 32 and the lower panel 34. The rear header 18 is disposed below the roof panel 38 along the opening 14. The back door upper 16 of the back door 10
Are spaced apart in the lateral direction of the vehicle body as shown in FIG.
Attached to the rear header by the hinge 40 of the place,
The back door 10 is opened and closed up and down. Since the structure of the hinge 40 itself and the structure for attaching the hinge 40 to the back door upper 16 and the rear header 18 are known, detailed description is omitted. In the embodiment shown in FIG. 1, the back door upper 16 of the back door 10 has a bulkhead 20 and the rear header 18 has a bulkhead 22. The bulkhead 20 has a closed sectional space 2 within the distance L between the hinges 40.
8, while the bulkhead 22 partitions the closed cross-sectional space 36 within the distance L between the hinges 40. Here, within the range of the interval L means the bulkhead 20,
22 means that the lateral width of the vehicle body does not become larger than the interval L. [0014] Shape from both the bulkhead 20 and 22 are both flat plate
And a central portion protruding from a peripheral portion. In the embodiment shown, the bulkhead 20 includes a peripheral portion 42 and a central portion 44 projecting from the peripheral portion 42.
The central portion 44 includes a flat first portion 45,
A semi-cylindrical second projecting further from the lower end of the first portion 45
And a portion 46. The first portion 45 and the second portion 46 have shapes substantially similar to the shape of the inner panel 26 in the back door upper 16. On the other hand, the bulkhead 22
Is composed of a peripheral portion 48 and a central portion 50 protruding from the peripheral portion 48, and the central portion 50 is a flat first portion 51.
And a flat second portion 52 further protruding from the center of the first portion 51. The second portion 52 includes the lower panel 34
Is in contact with The bulkhead may be formed so that the central portion protrudes from the peripheral portion.
The next moment is determined to be as large as possible. For example, the bulkhead 60 shown in FIG.
A flat central portion 64 protrudes from the peripheral portion 62, and the vertical walls 65, 6
6 are provided, and by increasing the height of these vertical walls, a large second moment of area can be exhibited. The bulkhead formed in this way has a larger second moment of area than a bulkhead of a simple flat plate, and therefore is excellent in the effect on twisting as described later in particular. The bulkhead has at least an upper side and a lower side of a peripheral portion sandwiched between panels defining a closed sectional space, and is fixed by spot welding as appropriate. As shown in FIG. 3, when a vertical force f is applied from the rear suspension while the vehicle is running, the back door 10 is twisted with respect to the vehicle body 12, and the back door 10 is twisted.
Is deformed as shown by a virtual line. Therefore, the distortion energy of the torsion becomes large at the center of the back door upper of the back door 10. According to the present invention, a large rigidity of the bulkhead can cope with a large strain energy and a twist of the back door 10 can be suppressed. As shown in FIG. 4, when a force F is applied to the back door 10 from the cylinder device 70, the back door 10 is vertically deformed with the two hinges 40 as nodes due to the force F and the reaction force F 'of the force. . Therefore, the degree of deformation between the hinges 40 increases, but according to the present invention, since the bulkhead having a large rigidity is arranged between the two hinges, the deformation can be suppressed. In the above embodiment, the bulkhead 20 is provided in the backdoor upper 16 of the backdoor 10 and the bulkhead 22 is provided in the rear header 18. In order to suppress the deformation of the central portion shown in (1), the bulk head may be provided on at least one of the back door upper 16 and the rear header 18.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of a mounting structure of a back door of an automobile according to the present invention, which is cut at a center of the back door. FIG. 2 is a perspective view of a bulkhead. FIGS. 3A and 3B show the influence of a force applied from a back door and a suspension of the vehicle, wherein FIG. 3A is a rear view of the vehicle, and FIG. 4 shows the effect of the force applied from the cylinder device, wherein a is a perspective view of the back door, b is a plan view seen from a direction substantially perpendicular to the back door glass, and c is a back view seen from the c direction of a. FIG. DESCRIPTION OF SYMBOLS 10 Back door 12 Body 14 Opening 16 Back door upper (mounting part) 18 Rear headers 20, 22, 60 Bulk head 24 Outer panel 26 Inner panels 28, 36 Closed section space 32 Upper panel 34 Lower panel

Claims (1)

(57) [Claim 1] A back as a mounting portion having a closed sectional space defined by an outer panel and an inner panel.
A back door having a door upper, a hinge having two closed spaces defined by an upper panel and a lower panel, and a rear header provided at an upper end of an opening for the back door of the vehicle body, spaced apart in a lateral direction of the vehicle body; And a mounting portion for the back door.
Is provided with a bulkhead for reinforcement within the spacing between said hinge dividing the closed section space, the bulkhead is formed by protruding a central portion of the plate from the peripheral portion surrounding this, both parts by the protrusion Vertical walls between them
It is, the mounting structure of the back door of the car.