JP7336102B2 - Underbody structure - Google Patents

Description

The present invention relates to a vehicle body lower structure.

2. Description of the Related Art Conventionally, there is known an automobile floor structure in which a front floor member is fitted into a concave portion of a side sill (see Patent Document 1). Adhesive is applied to the concave portion of the side sill, and the front floor member is fitted into the concave portion of the side sill and fixed by the adhesive.

JP-A-04-334672

When the vibration of the lower part of the vehicle body is transmitted to the upper part of the vehicle body and reaches near the passenger's ear, the passenger may perceive the sound as an undesirable sound. For this reason, for example, from the viewpoint of enhancing passenger comfort, it is important to suppress vibration transmission from the vehicle body lower structure to the vehicle body upper part.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and an object of the present invention is to provide a vehicle body lower part structure capable of suppressing vibration transmission from the vehicle body lower part to the vehicle body upper part.

A vehicle body lower structure that solves the above problems includes a pair of rocker members, a pair of side member outer members arranged outside the pair of rocker members, and a main body arranged straddling between the pair of rocker members. and a floor member, wherein both side portions of the vehicle lower portion structure include the pair of rocker members and the pair of side member outer members, and at least one side of the side portions The part is a joint in which the rocker member and the side member outer member are joined with a first adhesive, and the rocker member and the main floor member are joined with a second adhesive different from the first adhesive. The storage elastic modulus E1 of the first adhesive and the storage elastic modulus E2 of the second adhesive satisfy the relationship of E1>E2.

According to this configuration, between the main floor member and the rocker member, vibration can be preferentially absorbed by the second adhesive, which has a lower storage elastic modulus E2 than the storage elastic modulus E1 of the first adhesive. . Furthermore, the outside of the rocker member, that is, the rocker member and the side member outer member are joined by the first adhesive having the storage elastic modulus E1, thereby suppressing the occurrence of unnecessary vibration outside the rocker member. .

The vehicle body lower structure preferably further includes a rear floor member joined to the rear side of the vehicle body in the main floor member, and the main floor member and the rear floor member are joined together by the second adhesive.

According to this configuration, the vibration absorbing performance of the second adhesive can be exhibited at the rear-side end portion of the main floor member.
Preferably, the vehicle body lower structure further includes a front joint member that is joined to the front side of the vehicle body in the main floor member, and the main floor member and the front joint member are joined by the second adhesive.

According to this configuration, the vibration absorbing performance of the second adhesive can be exhibited at the front end portion of the main floor member.
In the vehicle body lower structure, the main floor member includes a main panel member and a hat-shaped member having a hat-shaped cross section, and the main panel member and the hat-shaped member are joined by the second adhesive. preferably.

According to this configuration, the vibration absorption performance of the second adhesive can be exhibited between the main panel member and the hat-shaped member that constitute the main floor member.

According to the present invention, transmission of vibration from the lower portion of the vehicle body to the upper portion of the vehicle body can be suppressed.

It is a perspective view which shows the vehicle body lower part structure in embodiment. It is an exploded perspective view showing a vehicle body lower part structure. Figure 3 is an end view taken along line 3-3 of Figure 1; Figure 4 is an end view taken along line 4-4 of Figure 1; Figure 5 is an end view taken along line 5-5 of Figure 1;

An embodiment of the vehicle body lower structure will be described below with reference to the drawings.
As shown in FIGS. 1 and 2, the vehicle body lower structure 11 includes a pair of rocker members 12a and 12b and a pair of side member outer members 13a and 13b arranged outside the pair of rocker members 12a and 12b, respectively. I have. The vehicle body lower structure 11 further includes a main floor member 21 arranged across the pair of rocker members 12a and 12b.

The pair of rocker members 12a and 12b extend along the longitudinal direction FR of the vehicle body. The pair of side member outer members 13a, 13b extend along the pair of rocker members 12a, 12b, respectively.

As shown in FIGS. 2 and 3, both side portions of the vehicle body lower structure 11 are provided with a pair of rocker members 12a and 12b and a pair of side member outer members 13a and 13b. On one side of the vehicle body lower structure 11, the rocker member 12a and the side member outer member 13a are joined with a first adhesive 71, and the rocker member 12a and the main floor member 21 are different from the first adhesive 71. It has a joint structure joined by a second adhesive 72 . On the other side of the vehicle body lower structure 11, the rocker member 12b and the side member outer member 13b are joined with a first adhesive 71, and the rocker member 12b and the main floor member 21 are different from the first adhesive 71. It has a joint structure joined by a second adhesive 72 . The storage elastic modulus E1 of the first adhesive 71 and the storage elastic modulus E2 of the second adhesive 72 satisfy the relationship of E1>E2.

In this joint structure, an adhesive layer L1 made of a first adhesive 71 is arranged between the rocker members 12a, 12b and the side member outer members 13a, 13b. An adhesive layer L2 made of a second adhesive 72 is arranged between the rocker members 12a and 12b and the main floor member 21. As shown in FIG.

As shown in FIGS. 1 and 2, the main floor member 21 of this embodiment includes a plurality of main panel members 22 and a plurality of hat-shaped members 23 having a hat-shaped cross section. The plurality of hat-shaped members 23 include a hat-shaped central member 23a extending along the longitudinal direction FR of the vehicle body at the central portion of the main floor member 21, and a plurality of hat-shaped central members 23a extending along the vehicle width direction W on the main floor member 21. hat-shaped cross member 23b. The plurality of hat-shaped cross members 23b include a plurality of hat-shaped cross members 23b adjacent to each other in the vehicle width direction W. As shown in FIG. Moreover, the plurality of hat-shaped cross members 23b includes a plurality of hat-shaped cross members 23b that are spaced apart in the longitudinal direction FR of the vehicle body.

As shown in FIGS. 2 and 3 , the main panel member 22 and the plurality of hat-shaped members 23 are joined with a second adhesive 72 . An adhesive layer L2a made of a second adhesive 72 is arranged between the main panel member 22 and the hat-shaped central member 23a. An adhesive layer L2b made of a second adhesive 72 is arranged between the main panel member 22 and the hat-shaped cross member 23b.

As shown in FIGS. 1 and 2, the vehicle body lower structure 11 includes a rear floor member 31 joined to the rear side of the vehicle body in the main floor member 21, and a front joining member joined to the front side of the vehicle body in the main floor member 21. 41.

As shown in FIGS. 2 and 4 , the main floor member 21 and the rear floor member 31 are joined together with a second adhesive 72 . That is, an adhesive layer L3 made of the second adhesive 72 is arranged between the main floor member 21 and the rear floor member 31. As shown in FIG. The rear floor member 31 of this embodiment has a rear panel member 31a and a rear coupling member 31b arranged between the rear panel member 31a and the main floor member 21. As shown in FIG. The rear panel member 31a and the rear joint member 31b are joined by a first adhesive 71. As shown in FIG. That is, an adhesive layer L3a made of the first adhesive 71 is arranged between the rear panel member 31a and the rear coupling member 31b.

As shown in FIGS. 2 and 5, the main floor member 21 and the front coupling member 41 are joined by a second adhesive 72 . That is, the adhesive layer L4 made of the second adhesive 72 is arranged between the main floor member 21 and the front coupling member 41 . Note that the front coupling member is arranged below the windshield.

Next, details of the first adhesive 71 and the second adhesive 72 will be described.
The storage elastic modulus E1 of the first adhesive 71 and the storage elastic modulus E2 of the second adhesive 72 satisfy the relationship of E1>E2 as described above, and the difference between the storage elastic moduli, E1−E2, is ΔE. Then, ΔE is preferably 0.3 GPa or more, more preferably 0.5 GPa or more. ΔE is preferably 7 GPa or less, more preferably 5 GPa or less.

The storage elastic modulus E1 of the first adhesive 71 is preferably 2 GPa or more, for example. In this case, the vibration of each member adhered with the first adhesive 71 can be more preferably suppressed. The storage elastic modulus E2 of the second adhesive 72 is preferably 1.5 GPa or less, for example. In this case, the vibration absorbing performance of the second adhesive 72 can be further enhanced.

The storage elastic modulus E1 of the first adhesive 71 is preferably 4 GPa or less, for example. The storage elastic modulus E2 of the second adhesive 72 is preferably 0.5 GPa or more, for example.
The storage elastic modulus E1 of the first adhesive 71 and the storage elastic modulus E2 of the second adhesive 72 are storage elastic moduli at 23° C. and can be measured using a dynamic viscoelasticity measuring device. A test piece of the first adhesive 71 and the second adhesive 72 can be produced by heating the first adhesive 71 and the second adhesive 72 at 170° C. for 20 minutes. The storage modulus measurement conditions using the dynamic viscoelasticity measuring device are as follows.

Test piece dimensions: 7 mm x 40 mm x 2 mm (thickness)
Deformation mode: Tensile Temperature range: -10°C to 200°C
Temperature rise: 2°C/min
Frequency: 1Hz
The first adhesive 71 and the second adhesive 72 are configured to be cured by heating, for example. The first adhesive 71 and the second adhesive 72 contain resin components. Examples of the resin component of the first adhesive 71 include epoxy resin. Examples of epoxy resins include bisphenol E type epoxy resins and bisphenol S type epoxy resins. Examples of the resin component of the second adhesive 72 include rubber-modified epoxy resin. A rubber-modified epoxy resin is an epoxy resin having two or more epoxy groups and a rubber skeleton, and examples of rubber include polybutadiene. The first adhesive 71 and the second adhesive 72 may contain, for example, a curing agent or a filler. Curing agents include, for example, dicyandiamide and 4,4'-diaminodiphenylsulfone. Examples of fillers include calcium carbonate and carbon black.

Next, a method for forming the vehicle body lower structure 11 will be described.
To form the vehicle body lower structure 11, first, for example, the first adhesive 71 is applied to the rocker members 12a, 12b or the side member outer members 13a, 13b, and the second adhesive 71 is applied to the rocker members 12a, 12b or the main floor member 21. An adhesive 72 is applied. As described above, in the method for forming the vehicle body lower part structure 11, after performing the adhesive application step of applying the first adhesive 71 or the second adhesive 72 to predetermined positions of the members constituting the vehicle body lower part structure 11, each member is are spot-welded. In the adhesive application step, for example, application methods such as spray, application gun, and brush application can be used.

Next, the vehicle body lower structure 11 can be formed by sequentially performing a cleaning process, an electrodeposition coating process, and a baking process. Here, the baking step is a step of baking the electrodeposition coating film using a heating furnace. Using this baking process, the first adhesive 71 and the second adhesive 72 can be cured by heating. In other words, the first adhesive 71 and the second adhesive 72 should be configured so as to be cured under the heating conditions of the baking process. The heating temperature in the baking process is, for example, 150° C. or higher and 180° C. or lower, and the heating time is, for example, 20 minutes or longer and 60 minutes or shorter.

Next, main functions of the vehicle body lower structure 11 will be described.
On both sides of the vehicle body lower structure 11, the rocker members 12a and 12b and the side member outer members 13a and 13b are joined with a first adhesive 71, and the rocker members 12a and 12b and the main floor member 21 are joined with a second adhesive. It has a joint structure joined by 72 . The storage elastic modulus E1 of the first adhesive 71 and the storage elastic modulus E2 of the second adhesive 72 satisfy the relationship of E1>E2. According to this configuration, the second adhesive 72 having a storage elastic modulus E2 lower than the storage elastic modulus E1 of the first adhesive 71 preferentially vibrates between the main floor member 21 and the rocker members 12a and 12b. can be absorbed. Furthermore, the outer sides of the rocker members 12a and 12b, that is, the rocker members 12a and 12b and the side member outer members 13a and 13b are joined together by a first adhesive 71 having a storage elastic modulus E1, whereby the rocker members 12a and 12b are bonded together. It is possible to suppress the occurrence of unnecessary vibration on the outside of the .

Next, the operation and effects of this embodiment will be described.
(1) The vehicle body lower structure 11 includes a pair of rocker members 12 a and 12 b, a pair of side member outer members 13 a and 13 b, and a main floor member 21 . On both sides of the vehicle body lower structure 11, the rocker members 12a and 12b and the side member outer members 13a and 13b are joined with a first adhesive 71, and the rocker members 12a and 12b and the main floor member 21 are joined with a second adhesive. It has a joint structure joined by 72 . The storage elastic modulus E1 of the first adhesive 71 and the storage elastic modulus E2 of the second adhesive 72 satisfy the relationship of E1>E2.

According to this configuration, since the above-described effects can be obtained, transmission of vibration from the lower portion of the vehicle body to the upper portion of the vehicle body can be suppressed.
(2) The vehicle body lower structure 11 further includes a rear floor member 31 joined to the main floor member 21 on the rear side of the vehicle body. The main floor member 21 and the rear floor member 31 are joined with a second adhesive 72 . In this case, the vibration absorption performance of the second adhesive 72 can be exhibited at the rear end of the main floor member 21 .

(3) The vehicle body lower structure 11 further includes a front coupling member 41 joined to the front side of the vehicle body in the main floor member 21 . The main floor member 21 and the front coupling member 41 are joined with a second adhesive 72 . In this case, the vibration absorption performance of the second adhesive 72 can be exhibited at the front end of the main floor member 21 .

(4) The main floor member 21 includes a main panel member 22 and a hat-shaped member 23 joined to the main panel member 22 . The main panel member 22 and the hat-shaped member 23 are joined with a second adhesive 72 . In this case, the vibration absorption performance of the second adhesive 72 can be exhibited between the main panel member 22 and the hat-shaped member 23 that constitute the main floor member 21 .

(Change example)
The above embodiment may be modified as follows. This embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.

- The joint portions of the respective members in the vehicle body lower structure 11 may be jointed using joint means other than the adhesive, or may be jointed using only the adhesive. Examples of bonding means other than adhesives include physical bonding methods such as spot welding. Also, the joint portion of the vehicle body lower structure 11 may include a joint portion using both the first adhesive 71 and the second adhesive 72 .

- The hat-shaped member 23 may be omitted, and the main floor member 21 may be composed only of the main panel member 22 .
- At least one joint portion that joins the hat-shaped member 23 and the main panel member 22 may be joined using an arbitrary adhesive, or may be joined without using an adhesive.

- In the above-described embodiment, as shown in FIG. 2, the configuration in which the hat-shaped central member 23a is joined between the plurality of main panel members 22 spaced apart along the vehicle width direction W has been exemplified. It is also possible to change to a structure in which the hat-shaped central member 23a is joined on one main panel member 22. FIG.

- A plurality of main panel members 22 may be changed to a single main panel member. In this case, the hat-shaped central member 23a may be omitted, and a central portion having a hat-shaped cross section may be formed in one main panel member so as to extend along the longitudinal direction FR of the vehicle body.

In the above-described embodiment, as shown in FIG. 2, the hat-shaped member 23 that constitutes the main floor member 21 includes one central hat-shaped member 23a that extends in the front-rear direction FR of the vehicle body, and a central hat-shaped member 23a that extends in the vehicle width direction W. There are four hat-shaped cross members 23b, but the number of hat-shaped members 23 is not particularly limited, and may be singular or plural.

In the above-described embodiment, as shown in FIG. 2, the main floor member 21 includes the hat-shaped member 23 extending along the front-rear direction FR or the vehicle width direction W of the vehicle body. It may have a hat-shaped member 23 extending therealong.

- The configuration may be changed so that the main panel members 22 of the main floor member 21 are composed of a plurality of members spaced apart along the longitudinal direction FR of the vehicle body, and the hat-shaped cross member 23b is joined between the plurality of main panel members 22. . That is, the hat-shaped cross member 23 b can be arranged so as to straddle between the plurality of main panel members 22 .

- The hat-shaped member 23 of the main floor member 21 is arranged so as to have a hat-shaped cross section that projects upward, but may be arranged so that it has a hat-shaped cross section that projects downward.

- The rear floor member 31 can be omitted. Also, the front coupling member 41 can be omitted.
- The joint portion where the main floor member 21 and the rear floor member 31 are joined may be joined using an arbitrary adhesive, or may be joined without using an adhesive.

- The joint portion where the rear panel member 31a and the rear joint member 31b are joined may be joined using an arbitrary adhesive, or may be joined without using an adhesive.
The rear floor member 31 of the above embodiment has a structure in which the rear panel member 31a and the rear coupling member 31b are joined together. It may be one formed member.

- The joint portion where the main floor member 21 and the front joint member 41 are joined may be joined using an arbitrary adhesive or may be joined without using an adhesive.
- As the first adhesive 71, a plurality of types of first adhesives 71 having different storage elastic moduli E1 can be used. For example, the storage elastic modulus E1 of the first adhesive 71 that joins the rocker members 12a and 12b and the side member outer members 13a and 13b, and the storage elastic modulus E1 of the first adhesive 71 that joins the rear panel member 31a and the rear coupling member 31b. The elastic modulus E1 may be the same or different.

- As the 2nd adhesive agent 72, the 2nd adhesive agent 72 of multiple types from which the storage elastic modulus E2 differs can also be used. For example, the storage elastic modulus E2 of the second adhesive 72 that joins the rocker members 12a and 12b and the main floor member 21 and the storage elastic modulus E2 of the second adhesive 72 that joins the main floor member 21 and the rear floor member 31 may be the same or different.

In the vehicle body lower part structure 11, both side parts of the vehicle body lower part structure 11 have a joint structure that is joined using the first adhesive 71 and the second adhesive 72. Among the two side parts of the vehicle body, Either side may have an optional adhesive or a joining structure that is joined without adhesive.

- The member constituting the vehicle body lower structure may be formed from a metal material such as a steel plate, or may be formed from a non-metal material such as a resin material.

DESCRIPTION OF SYMBOLS 11... Vehicle body lower part structure 12a, 12b... Locker member 13a, 13b... Side member outer member 21... Main floor member 22... Main panel member 23... Hat-shaped member 23a... Hat-shaped central member 23b... Hat-shaped cross member 31... Rear floor member 31a... rear panel member 31b... rear joint member 41... front joint member 71... first adhesive 72... second adhesive L1, L2, L2a, L2b, L3, L3a, L4... adhesive layer FR... longitudinal direction W... vehicle width direction

Claims (4)

a pair of rocker members;
a pair of side member outer members respectively arranged outside the pair of rocker members;
a main floor member disposed across the pair of rocker members,
Both side portions of the vehicle body lower structure include the pair of rocker members and the pair of side member outer members,
At least one of the side portions,
A joint structure in which the rocker member and the side member outer member are joined with a first adhesive, and the rocker member and the main floor member are joined with a second adhesive different from the first adhesive. death,
The storage elastic modulus E1 of the first adhesive and the storage elastic modulus E2 of the second adhesive satisfy the relationship of E1>E2 , and the difference between the storage elastic modulus E1 and the storage elastic modulus E2 A certain ΔE=E1−E2 is 0.3 GPa or more, the underbody structure. further comprising a rear floor member joined to the rear side of the vehicle body in the main floor member;
2. The vehicle body lower structure according to claim 1, wherein said main floor member and said rear floor member are joined by said second adhesive. further comprising a front coupling member joined to the front side of the vehicle body in the main floor member;
3. The underbody structure according to claim 1, wherein the main floor member and the front coupling member are joined by the second adhesive. The main floor member includes a main panel member and a hat-shaped member having a hat-shaped cross section,
The vehicle body lower part structure according to any one of claims 1 to 3, wherein the main panel member and the hat-shaped member are joined by the second adhesive.