JP7500477B2 - Body manufacturing method - Google Patents

Description

The present invention relates to a method for manufacturing a vehicle body.

In an automobile body structure, a pair of roof side rails extending in the fore-and-aft direction of the vehicle are connected by a roof reinforcement extending in the vehicle width direction. A flat roof panel is placed on top of the roof reinforcement, and the roof reinforcement and roof panel are bonded together with a mastic adhesive. The roof reinforcement may also be connected to both ends of the roof panel in the vehicle width direction.

In some cases, the roof side rails are made of steel, while the roof reinforcement and roof panel are made of aluminum alloy. Since the thermal expansion coefficients of steel and aluminum alloy are different, there is a risk of thermal strain occurring when the vehicle body is heated during the paint drying process or the like. In other words, while the roof panel and roof reinforcement, which are relatively prone to thermal expansion, tend to expand significantly, the roof side rails, which are relatively resistant to thermal expansion, restrain the deformation of the roof panel and roof reinforcement in the vehicle width direction. As a result, the roof panel and roof reinforcement expand toward the top of the vehicle, but the roof reinforcement is more likely to expand because there are fewer restraining points compared to the roof panel. Therefore, the gap between the roof panel and the roof reinforcement becomes smaller, and the mastic adhesive located between the roof panel and the roof reinforcement is crushed. If this state is maintained, the mastic adhesive will heat harden in a crushed state, and the gap between the roof panel and the roof reinforcement will remain small even after cooling. Therefore, when the roof reinforcement returns to its original shape, the roof panel is pulled by the roof reinforcement, and the joint with the mastic is deformed as if it were concave. Such deformations mar the appearance of the vehicle body and must be suppressed.

Patent Document 1 discloses a method for manufacturing a vehicle body that aims to reduce deformation of the roof panel. In this method, the adhesive (thermosetting sealer) that bonds the roof panel and roof reinforcement is heated and pre-cured before the paint drying process. As a result, even if the entire vehicle body is heated in the paint drying process, the roof panel and roof reinforcement are firmly bonded by the already cured adhesive, so deformation of the roof panel can be reduced.

JP 2009-61854 A

In the vehicle body manufacturing method of Patent Document 1, a heating process for heating the adhesive is carried out separately from the paint drying process in which the entire vehicle body is placed in a high-temperature environment, so additional equipment is required to perform partial heating. Furthermore, the number of processes increases, and the takt time is also extended. Therefore, the vehicle body manufacturing method of Patent Document 1 is not efficient and there is room for improvement.

The objective of the present invention is to efficiently suppress deformation of the roof panel in a vehicle body manufacturing method.

The present invention relates to
preparing an aluminum alloy roof reinforcement extending in a width direction of a vehicle body, a flat aluminum alloy roof panel, and a pair of steel roof side rails extending in a front-rear direction of the vehicle body;
The roof reinforcement is fixed so as to connect both ends of the pair of roof side rails or the roof panel in the width direction,
placing the roof panel on the roof reinforcement via a thermosetting mastic adhesive;
and subjecting the vehicle body to a heating step in a state in which upward deformation of the central portion in the width direction of the roof reinforcement is restricted.

According to the above method, the vehicle body is subjected to the heating process while limiting the upward deformation of the central portion of the roof reinforcement in the width direction, and therefore the gap between the roof reinforcement and the roof panel can be prevented from becoming significantly smaller. This prevents the mastic adhesive from being crushed and hardened, i.e., prevents the roof panel from being deformed so as to become concave. In addition, in the above, "subjecting the vehicle body to the heating process" means that the roof reinforcement, the roof panel, and the pair of roof side rails are heated not only partially but also overall. Therefore, since the heating process can heat the entire vehicle body rather than only partially, it may correspond to, for example, a paint drying process. In this case, no additional equipment is required and the number of processes is not increased, which is efficient.

The method for manufacturing the vehicle body includes:
Further preparing a deformation limiting member made of a material having a smaller thermal expansion coefficient and a higher Young's modulus than the aluminum alloy;
The method may further include connecting the central portion in the width direction of the roof reinforcement to another portion of the vehicle body by the deformation limiting member.

According to this method, the deformation limiting member can specifically limit the upward deformation of the widthwise center of the roof reinforcement. The deformation limiting member is made of a material with a smaller thermal expansion coefficient and a higher Young's modulus than aluminum alloy, so it does not deform as much as the roof panel, even in high-temperature environments such as paint drying processes. Therefore, the gap between the roof panel and the roof reinforcement can be more reliably maintained at an appropriate size.

The method for manufacturing the vehicle body includes:
a mass body having a weight for limiting upward deformation of the central portion of the roof reinforcement in the width direction;
The method may further include suspending the mass body at a central portion in the width direction of the roof reinforcement.

This method allows the mass body to specifically limit the upward deformation of the central part of the roof reinforcement in the vehicle width direction. Therefore, the gap between the roof panel and the roof reinforcement can be more reliably maintained at an appropriate size. In particular, the mass body can be suspended easily because it can be achieved without the need for connection to other members.

According to the present invention, deformation of the roof panel can be effectively suppressed in a vehicle body manufacturing method.

FIG. FIG. 2 is a schematic perspective view of a vehicle with a roof panel removed from the vehicle body. FIG. 2 is a schematic plan view of a roof panel. 3 is a cross-sectional view perpendicular to the vehicle body front-rear direction, showing a first step of the method for manufacturing the vehicle body according to the first embodiment of the present invention. FIG. 5 is a cross-sectional view perpendicular to the vehicle body front-rear direction, showing a second step of the method for manufacturing a vehicle body according to the first embodiment of the present invention. FIG. 5 is a cross-sectional view perpendicular to the vehicle body front-rear direction, showing a third step of the method for manufacturing a vehicle body according to the first embodiment of the present invention. FIG. 11 is a cross-sectional view perpendicular to the vehicle body front-rear direction, showing a first step of a method for manufacturing a vehicle body according to a comparative example. 13 is a cross-sectional view perpendicular to the vehicle body front-rear direction, showing a second step of the vehicle body manufacturing method of the comparative example. FIG. 13 is a cross-sectional view perpendicular to the vehicle body front-rear direction, showing a third step of the vehicle body manufacturing method of the comparative example. FIG. 13 is a cross-sectional view perpendicular to the vehicle body front-rear direction, showing a first step of a method for manufacturing a vehicle body according to a second embodiment of the present invention. FIG. 13 is a cross-sectional view perpendicular to the vehicle body front-rear direction, showing a second step of the method for manufacturing a vehicle body according to the second embodiment of the present invention. FIG. 13 is a cross-sectional view perpendicular to the vehicle body front-rear direction, showing a third step of the method for manufacturing a vehicle body according to the second embodiment of the present invention. FIG.

The following describes an embodiment of the present invention with reference to the attached drawings.

First Embodiment
1 and 2, a method for manufacturing a vehicle body 1 having a structure in which an aluminum alloy roof panel 34 is joined to a pair of steel roof side rails 36 via an aluminum alloy roof reinforcement 35 will be described.

In Figures 1 and 2, the front-rear direction of the vehicle body 1 is indicated by the symbol X, the width direction is indicated by the symbol Y, and the up-down direction is indicated by the symbol Z. This is the same in the subsequent figures. In this embodiment, a general passenger car is used as an example of the vehicle body 1, but the type and shape of the vehicle body 1 are not particularly limited.

The vehicle body 1 includes a front section 10, a rear section 20, and a middle section 30.

The front section 10 is the portion configured at the front of the vehicle body 1, and includes a front frame 11 and a front bumper 12. The front frame 11 forms the skeleton of the front section 10. An engine housing section 13 for mounting an engine and the like (not shown) is formed in the center of the front frame 11. Front wheel housing sections 14 for accommodating front wheels (not shown) are formed on both sides of the front frame 11 in the width direction. A front bumper 12 is disposed in front of the front frame 11 so as to extend in the width direction.

The rear section 20 is a portion configured at the rear of the vehicle body 1, and includes a rear frame 21. The rear frame 21 forms the framework of the rear section 20. A trunk section 22 is formed in the center rear of the rear frame 21. Rear wheel storage sections 23 for storing rear wheels (not shown) are formed on both sides of the rear frame 21 in the width direction.

The middle section 30 is a section configured in the center of the vehicle body 1, and includes a center frame 31 and a floor panel 32. The center frame 31 forms the skeleton of the middle section 30. A cabin 33 for a user to ride in is formed in the center of the center frame 31. The floor panel 32 forms the floor surface of the cabin 33.

The center frame 31 has a pair of front pillars 39, a pair of center pillars 40, and a pair of rear pillars 41 that extend in the vertical direction. The center frame 31 also has a pair of roof side rails 36 that extend in the front-rear direction, and a roof front rail 37 and a roof rear rail 38 that extend in the width direction. When the vehicle body 1 is viewed from above, the pair of roof side rails 36, roof front rail 37, and roof rear rail 38 are connected to each other and form a rectangular shape. When the vehicle body 1 is viewed from the side, the pair of front pillars 39, the pair of center pillars 40, and the pair of rear pillars 41 support the pair of roof side rails 36, roof front rail 37, and roof rear rail 38 from below.

The pair of roof side rails 36 are fixed between the upper ends of a pair of front pillars 39, a pair of center pillars 40, and a pair of rear pillars 41. The roof front rail 37 is disposed and fixed along the vehicle width direction, spanning between the upper ends of the pair of front pillars 39. The roof rear rail 38 is fixed along the width direction, spanning between the upper ends of a pair of rear pillars 143.

Referring also to FIG. 3, a roof reinforcement 35 extending in the width direction is fixed to connect each of a pair of roof side rails 36. A thermosetting mastic adhesive 42 is applied to the center of the upper surface of the roof reinforcement 35, and the roof panel 34 is adhered to the roof reinforcement 35 by the mastic adhesive 42. The roof reinforcement 35 is made of the same aluminum alloy as the roof panel 34.

The roof panel 34 is an exterior panel that constitutes the upper part of the vehicle body 1. The roof panel 34 is effectively prevented from deforming by the manufacturing method of the vehicle body 1 of this embodiment, as described below.

Referring to FIG. 4, in the manufacturing method of the vehicle body 1 of this embodiment, first, the roof reinforcement 35 is fixed so as to connect the pair of roof side rails 36. Then, a thermosetting mastic adhesive 42 is applied onto the roof reinforcement 35. At this time, the mastic adhesive 42 has not yet been heated. Then, the roof panel 34 is placed on the roof reinforcement 35 via the mastic adhesive 42. The roof panel 34 is fixed to the pair of roof side rails 36 in the same way as the roof reinforcement 35. Therefore, the roof panel 34 and the roof reinforcement 35 are restrained from deformation in the width direction.

When unheated, the mastic adhesive 42 has no adhesive strength and is flexible. When unheated, the mastic adhesive 42 has enough viscosity to maintain its shape, and in the illustrated example, has a roughly circular cross section.

In this embodiment, before a heating process such as a paint drying process described later is performed, a steel wire (deformation limiting member) 43 connects a widthwise central portion 35a of the roof reinforcement 35 to the floor panel 32. Steel is a material that has a smaller thermal expansion coefficient and a higher Young's modulus than aluminum alloys. Therefore, the steel wire 43 is less susceptible to thermal effects than the roof reinforcement 35 and the roof panel 34. Examples of physical property values include a thermal expansion coefficient of steel of about 11×10 ⁻⁶ /° C. and a Young's modulus of about 206 GPa. A thermal expansion coefficient of aluminum alloys is about 24×10 ⁻⁶ /° C. and a Young's modulus of about 70 GPa. Thus, the steel wire 43 limits the upward deformation of the widthwise central portion 35a of the roof reinforcement 35.

Referring to FIG. 5, the roof panel 34 and roof reinforcement 35 are restrained in the width direction by a pair of roof side rails 36, so when the vehicle body 1 is subjected to a paint drying process (an example of a heating process), they thermally expand upward in a bow shape. However, due to their structure, they do not thermally expand downward. At this time, the steel wire 43 keeps the gap D between the roof panel 34 and the roof reinforcement 35 roughly constant. Therefore, the mastic adhesive 42 hardens while maintaining a roughly circular cross-sectional shape.

Referring to FIG. 6, when the vehicle body 1 is cooled after the paint drying process, the thermal expansion of the roof panel 34 and roof reinforcement 35 subsides. At this time, the gap D between the roof panel 34 and the roof reinforcement 35 is kept constant by the hardened mastic adhesive 42. The size of the gap D can be adjusted by adjusting the tension of the steel wire 43. Preferably, the tension of the steel wire 43 is adjusted so that the size of the gap D is 1 to 5 mm.

Although different from this embodiment, a comparative example in which the steel wire 43 is not used will be described with reference to Figures 7 to 9 to facilitate understanding.

Referring to FIG. 7, in the comparative example, a pair of roof side rails 36, a roof reinforcement 35, a roof panel 34, and a mastic adhesive 42 are arranged in the same manner as in FIG. 4. In the state shown in FIG. 7, the mastic adhesive 42 is in an unheated state, and in the illustrated example, has a roughly circular cross section.

Referring to FIG. 8, similarly to FIG. 6, the roof panel 34 and roof reinforcement 35 thermally expand upward in a bow shape when the vehicle body 1 is subjected to the paint drying process. At this time, the roof panel 34 is fixed to the roof front rail 37 (see FIG. 3), the roof rear rail 38 (see FIG. 3), and the pair of roof side rails 36, while the roof reinforcement 35 is fixed only to the pair of roof side rails 36. Therefore, the roof reinforcement 35 is more likely to expand since it has fewer fixed points than the roof panel 34, and the gap D between the roof panel 34 and the roof reinforcement 35 becomes smaller. As a result, the mastic adhesive 42 is heated and hardened in a vertically crushed state.

Referring to FIG. 9, when the vehicle body 1 is cooled after the paint drying process, the thermal expansion of the roof panel 34 and roof reinforcement 35 subsides. At this time, the gap D between the roof panel 34 and the roof reinforcement 35 is made smaller than it was initially (see FIG. 6) by the mastic adhesive 42 that has been crushed and hardened in the vertical direction. Therefore, the roof panel 34 is pulled downward by the roof reinforcement 35 via the mastic adhesive 42, and the central portion 34a in the width direction is deformed as if it is recessed.

The manufacturing method for the vehicle body 1 of this embodiment can effectively suppress deformation of the roof panel 34 as shown in FIG. 9. Specifically, this is as follows.

The vehicle body 1 is subjected to the paint drying process with the upward deformation of the widthwise central portion 35a of the roof reinforcement 35 restricted, so that the gap D between the roof reinforcement 35 and the roof panel 34 is prevented from becoming significantly smaller. This prevents the mastic adhesive 42 from being crushed and hardened, i.e., prevents a part of the roof panel 34 (e.g., the central portion 34a) from being deformed in a concave manner. In addition, the paint drying process is an existing vehicle body manufacturing process, so it is efficient because it does not require additional equipment or increase the number of processes.

The steel wire 43 can specifically limit the upward deformation of the widthwise central portion 35a of the roof reinforcement 35. The steel wire 43 is made of a material with a smaller thermal expansion coefficient and a higher Young's modulus than aluminum alloy, so it does not deform as much as the roof panel 34, even in high-temperature environments such as paint drying processes. This makes it possible to more reliably maintain the gap D between the roof panel 34 and the roof reinforcement 35 at an appropriate size. Note that, in this embodiment, the steel wire 43 has been described as an example of a deformation limiting member, but it is not limited to the steel wire 43 and any member that performs a similar function may be used.

Second Embodiment
The manufacturing method of the vehicle body 1 of this embodiment shown in Figures 10 to 12 uses a mass body 44 instead of the steel wire 43 (see Figures 4 to 6). Other than this, the manufacturing method is substantially the same as the first embodiment. Therefore, the description of the parts shown in the first embodiment may be omitted.

Figures 10 to 12 correspond to Figures 4 to 6 of the first embodiment.

In the manufacturing method of the vehicle body 1 of this embodiment, a pair of roof side rails 36, a roof reinforcement 35, a roof panel 34, and a mastic adhesive 42 are arranged in the same manner as in FIG. 4. In the state shown in FIG. 10, the mastic adhesive 42 is in an unheated state, and in the illustrated example, has a roughly circular cross section.

In this embodiment, before undergoing a heating process such as a paint drying process described below, the mass body 44 is suspended from the widthwise central portion 35a of the roof reinforcement 35. The mass body 44 has a weight that limits the upward deformation of the widthwise central portion 35a of the roof reinforcement 35. Therefore, the mass body 44 limits the upward deformation of the widthwise central portion 35a of the roof reinforcement 35.

Referring to FIG. 11, when the vehicle body 1 is subjected to the paint drying process, it thermally expands upward in a bow shape. At this time, the mass body 44 keeps the gap D between the roof panel 34 and the roof reinforcement 35 approximately constant. Therefore, the mastic adhesive 42 hardens while maintaining its approximately circular cross-sectional shape.

Referring to FIG. 12, when the vehicle body 1 is cooled after the paint drying process, the thermal expansion of the roof panel 34 and roof reinforcement 35 subsides. At this time, the gap D between the roof panel 34 and the roof reinforcement 35 is kept constant by the hardened mastic adhesive 42. The size of the gap D can be adjusted by adjusting the weight of the mass body 44. Preferably, the weight of the mass body 44 is adjusted so that the size of the gap D is 1 to 5 mm.

According to the manufacturing method of the vehicle body 1 of this embodiment, the mass body 44 can specifically limit the upward deformation of the central portion 35a of the roof reinforcement 35 in the vehicle width direction. Therefore, the gap between the roof panel 34 and the roof reinforcement 35 can be more reliably maintained at an appropriate size. In particular, the mass body 44 can be suspended easily because it can be achieved without the need for connection to other members.

Although specific embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the present invention. For example, the mass body 44 of the second embodiment may be suspended from the roof reinforcement 35 and placed on the floor panel 32. Furthermore, the roof reinforcement 35 may be fixed to both widthwise ends 34b (see FIG. 3) of the roof panel 34, rather than to a pair of roof side rails 36.

REFERENCE SIGNS LIST 1 vehicle body 10 front portion 11 front frame 12 front bumper 13 engine housing portion 14 front wheel housing portion 20 rear portion 21 rear frame 22 trunk portion 23 rear wheel housing portion 30 middle portion 31 center frame 32 floor panel 33 cabin 34 roof panel 34a center portion 34b both ends 35 roof reinforcement 35a center portion 36 roof side rail 37 roof front rail 38 roof rear rail 39 front pillar 40 center pillar 41 rear pillar 42 mastic adhesive 43 steel wire (deformation limiting member)
44 Mass body

Claims (2)

a roof reinforcement made of an aluminum alloy and extending in the width direction of a vehicle body, a flat roof panel made of an aluminum alloy, a pair of steel roof side rails extending in the front-rear direction of the vehicle body , a deformation limiting member made of a material having a smaller thermal expansion coefficient and a higher Young's modulus than an aluminum alloy, and a floor panel constituting a floor surface of a cabin of the vehicle body ,
The roof reinforcement is fixed so as to connect both ends of the pair of roof side rails or the roof panel in the width direction,
placing the roof panel on the roof reinforcement via a thermosetting mastic adhesive;
and subjecting the vehicle body to a heating step in a state in which upward deformation of the central portion in the width direction of the roof reinforcement is restricted by connecting the central portion in the width direction of the roof reinforcement to the floor panel of the vehicle body with the deformation limiting member. a roof reinforcement made of an aluminum alloy and extending in a width direction of a vehicle body, a flat roof panel made of an aluminum alloy, a pair of steel roof side rails extending in a front-rear direction of the vehicle body , and a mass body having a weight for limiting upward deformation of a central portion of the roof reinforcement in the width direction ;
The roof reinforcement is fixed so as to connect both ends of the pair of roof side rails or the roof panel in the width direction,
placing the roof panel on the roof reinforcement via a thermosetting mastic adhesive;
and subjecting the vehicle body to a heating step in a state in which upward deformation of the central portion in the width direction of the roof reinforcement is restricted by suspending the mass body from the central portion in the width direction of the roof reinforcement.

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