JP2005170270A - Vehicle body structure for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle body structure for a vehicle allowing the relaxing of the concentration of stress to a vehicle body structure at the periphery of a rear floor panel and achieving the light weight of the vehicle body by utilizing a spare tire and capable of enhancing the operation stability of the vehicle by suppressing the deformation of a rear floor panel. <P>SOLUTION: In the vehicle body structure for the vehicle, a spare tire 48 is stored in a recessed part 44 formed on the rear floor panel 36 of the vehicle body. The structure has a plurality of viscous-elastic members 52 provided between the recessed part of the rear floor panel and the spare tire so as to be abutted on the spare tire and aligned in a vehicle width direction and has a viscosity attenuation characteristic wherein these viscous-elastic members receive forces from the recessed part of the rear floor panel and the spare tire and generates a predetermined viscosity attenuation force. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a vehicle body structure of a vehicle, and more particularly to a vehicle body structure of a vehicle that houses a spare tire in a recess formed in a rear floor panel of the vehicle body.

The body of an automobile is deformed by receiving a force from the road surface when traveling, for example, the floor of the body is mainly torsionally deformed when turning, and is bent and deformed mainly in the front-rear direction during braking or acceleration.
Since these deformations of the vehicle body affect the operability of the vehicle, conventionally, reinforcing members that reinforce each part of the vehicle body have been provided around the front of the engine room, around the vehicle compartment, and around the rear near the rear wheel. It is provided in the basic structure of the vehicle body to increase the rigidity of the vehicle body.

As such a reinforcing member, there is a suspension tower bar that connects the suspension towers of the front wheels or the rear wheels to increase rigidity. This suspension tower bar is a reinforcing member that is integrally formed of an elastic body such as metal, and energy due to deformation of the reinforcing member acts on the vehicle body as a repulsive force, so that there is a problem that steering stability and riding comfort are impaired. Existed. Moreover, if the rigidity of the reinforcing member is increased in order to keep the deformation amount of the reinforcing member small, there is a problem that the weight increases and stress concentration around the mounting portion is caused.
Patent Document 1 proposes a reinforcing member including a hydraulic damper or a viscoelastic member that generates a viscous damping force in order to solve the problem of such a reinforcing member.

Japanese Patent Laid-Open No. 2002-211437

  On the other hand, in order to reduce the weight of the car body as much as possible while ensuring the desired car body rigidity, limit the number of points and points of use of the reinforcing members so as not to increase the rigidity and strength of each part of the car body more than necessary. Therefore, it is necessary to optimally design the cross-sectional dimensions and thickness of the vehicle body constituent members. In particular, in open cars, lightweight sports cars, etc., there is a strong demand for ensuring the desired vehicle body rigidity and reducing the weight.

  Here, since the rear floor panel is provided at the rear part of the vehicle body to which the rear suspension is attached, the rigidity of the rear floor panel greatly affects the maneuverability of the vehicle. In particular, if the rear floor panel is deformed by torsional deformation of the entire vehicle body, the vehicle's maneuverability and riding comfort are adversely affected.

  However, when the rigidity of the rear floor panel is greatly increased locally by the reinforcing member, stress concentrates on other members such as the vehicle body structure around the rear floor panel, for example, the pillar of the vehicle body, and cracks are generated, resulting in damage. Or spot welding that holds the structural parts of the car body is lost. For this reason, it is necessary to arrange reinforcing members at various locations on the vehicle body around the floor where stress is concentrated, or to increase the cross-sectional dimension or increase the plate thickness in order to increase the rigidity and strength of the above-described pillars and the like. Therefore, it has been difficult to achieve weight reduction.

Here, the rear floor panel is often formed with a recess for storing the spare tire. Even in the rear floor panel in which such a recess is formed, it is necessary to suppress the deformation. Even if the reinforcing member is provided, the rear floor panel constitutes the floor portion of the cargo compartment, and therefore there are many restrictions on arrangement in order to secure the cargo compartment space. In particular, such a restriction becomes conspicuous in a rear floor panel in which a recess for storing a spare tire is formed.
Accordingly, the present inventors paid attention to the fact that the spare tire has a constant weight and rigidity and is arranged so as to extend substantially parallel to the rear floor panel, and has attempted to solve the above-described problems of the prior art.

  The present invention has been made to solve the above-described problems of the prior art, and by using a spare tire, the stress concentration on the vehicle body structure around the rear floor panel is reduced and the weight of the vehicle body is reduced. It is an object of the present invention to provide a vehicle body structure that can suppress the deformation of the panel and improve the operability of the vehicle.

In order to achieve the above object, the present invention provides a vehicle body structure for a vehicle in which a spare tire is accommodated in a recess formed in a rear floor panel of the vehicle body, and the spare tire is placed between the recess of the rear floor panel and the spare tire. A plurality of viscoelastic members provided so as to be in contact with each other and arranged in the vehicle width direction, and these viscoelastic members receive a force from the recesses of the rear floor panel and a spare tire to generate a predetermined viscous damping force. It is characterized by having.
In the present invention configured as described above, a plurality of viscoelastic members that generate a predetermined viscous damping force by receiving a force from the recess of the rear floor panel and the spare tire are arranged in the vehicle width direction. The deformation energy is absorbed and the deformation is allowed to some extent according to the deformation speed of the deformation in the vehicle width direction generated in the rear floor panel, and the reaction force due to the deformation of the viscoelastic member suppresses the deformation of the rear floor panel. This increases the rigidity of the rear floor panel. Therefore, the deformation of the rear floor panel can be suppressed and the torsional deformation of the vehicle body can be suppressed without greatly increasing the rigidity of the rear floor panel.

Preferably, in the present invention, it further includes a plurality of elastic members provided in contact with the spare tire between the recessed portion of the rear floor panel and the spare tire and arranged in the vehicle body front-rear direction. Along with the spare tire, it has a spring characteristic that functions as a dynamic damper at a predetermined frequency.
In the present invention configured as described above, a plurality of elastic members having spring characteristics that function as dynamic dampers at a predetermined frequency together with the spare tire are arranged in the longitudinal direction of the vehicle body. It functions as a dynamic damper at the resonance frequency of the longitudinal bending vibration of the vehicle body (so-called secondary vibration of the vehicle body), suppresses the bending vibration in the longitudinal direction of the entire vehicle body, and noise in the vehicle interior due to acoustic radiation of the bending vibration As well as the vehicle operability.

  Preferably, in the present invention, the viscoelastic member includes a plate-like viscoelastic body and a pair of plate-like attachment members provided on the upper and lower surfaces of the viscoelastic body, and the attachment provided on the lower surface. The member is fixed in the recess of the rear floor panel, and the mounting member provided on the upper surface comes into contact with the tire of the spare tire.

  According to the present invention, the spare tire is used to reduce the stress concentration on the vehicle body structure around the rear floor panel and reduce the weight of the vehicle body. I can do it.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a perspective view showing an underbody 1 of a vehicle body having a vehicle body structure according to an embodiment of the present invention.
As shown in FIG. 1, an underbody 1 of a vehicle body having a vehicle body structure according to a first embodiment of the present invention includes a pair of front side frames 2 extending in the longitudinal direction of the vehicle body as basic reinforcing frames of the vehicle body. A pair of side sills 4, a pair of floor side frames 6, and a pair of rear side frames 8, respectively, No. 2 extending in the vehicle width direction. 1 cross member 10, no. 2 Cross member 12, No. 2 3 cross member 14 and no. 4 cross members 16. No. The one cross member 10 includes a pair of torque box members 18 and a dash lower cross member 20.

  A pair of front side frames 2 and No. 2 A front suspension cross member 22 is attached to one cross member 10, and a front suspension 24 is attached to the front suspension cross member 22. An engine 26 is attached between the pair of front side frames 2. A rear suspension cross member 28 is attached to the pair of rear side frames 8, and a rear suspension 30 is attached to the rear suspension cross member 28.

  The underbody 1 further includes a front floor panel 32 that is connected to the plurality of frame members to form a floor portion of the passenger compartment, and a center floor that is disposed at a position higher than the front floor panel 32 at the rear of the vehicle body. A panel 34 and a rear floor panel 36 which is disposed behind the center floor panel 34 and which forms the floor portion of the cargo compartment are provided.

  The front floor panel 32 is formed by integrally pressing a steel plate, and a floor tunnel 38 is formed so as to extend in the longitudinal direction of the vehicle body at a substantially central position in the vehicle width direction. The front edge of the front floor panel 32 on the vehicle body front side is joined to the lower edge of the dash panel 40 that partitions the vehicle compartment from the engine room by spot welding or the like. Are attached to a side body (not shown) of an automobile, and the dash panel 40 and the side body are connected to a pillar, a ceiling part (not shown), and the like constituting the passenger compartment. Has been.

  Next, the structure of the rear floor panel according to the present embodiment will be described with reference to FIGS. 2 is an enlarged plan view of the rear floor panel of FIG. 1, FIG. 3 is a cross-sectional view taken along line III-III of FIG. 2, and FIG. 4 is applied to the present embodiment. It is a perspective view which shows a viscoelastic member.

  The rear floor panel 36 is formed by integrally pressing a steel plate having a predetermined thickness (for example, a thickness of 0.65 to 0.7 mm). 4 The cross member 16 and the rear body 42 are joined to each other by spot welding or the like, and at a substantially central position in the vehicle width direction, a recess 44 for accommodating a spare tire, that is, a so-called spare tire house 44 is opened rearward. It is integrally formed so as to protrude downward.

  As shown in FIGS. 2 and 3, a wheel support portion 46 is formed on the bottom portion 44a of the spare tire house 44 at the center in the vehicle longitudinal direction and the vehicle width direction. The spare tire 48 is positioned at a predetermined position by 46a, and the shoulder tire 46b supports the spare tire 48 in the vertical direction of the vehicle body via the elastic pad 50. The spare tire is bolted (not shown) to the vehicle body. The position in the vertical direction is fixed so as not to deviate greatly.

  A pair of viscoelastic support members (viscoelastic members) 52 are provided on the left and right sides of the wheel support portion 46 in the vehicle width direction. These viscoelastic support members 52 are each deformed as shown in FIG. A plate-like viscoelastic body 54 that generates a predetermined viscous damping force and reaction force according to speed and displacement, and a pair of steel plate-like mounting members 56 respectively bonded to the upper and lower surfaces of the viscoelastic body; It has.

  Here, it is known that the floor of the vehicle body undergoes torsional deformation and bending deformation during traveling, and these torsional deformation and bending deformation mainly involve vibrations of 15 to 25 Hz. In the present embodiment, the viscoelastic support member 52 suppresses torsional deformation and bending deformation of the floor. Hereinafter, the viscoelastic support member 52 will be specifically described.

The viscoelastic body 54 is a rectangular plate made of a silicon-based or diene-based viscoelastic material (viscoelastic material), and has a predetermined viscous damping force and reaction force according to the deformation speed and the deformation amount. It is what produces. As a characteristic value unique to the viscoelastic material, a tan delta value (tan δ _K ) is 0.7 to 1.0. Further, the real number component (K ′) and the imaginary number component (K ″) of the stiffness value of the viscoelastic support member 52 provided with the viscoelastic body 54 on the mounting member 56 are each in the range of about 15 Hz to 25 Hz at room temperature. 100 to 700 N / mm and 80 to 500 N / mm are shown.

  The viscoelastic support member 52 is fixed at a position and height such that when the spare tire 48 is attached to the wheel support portion 46, the upper surface 56 a abuts against the tire 48 a of the spare tire 48. Specifically, the lower surface 56b of one attachment member 56 on the vehicle body lower side is bonded to the bottom 44a of the spare tire house 44, and the upper surface 56a of the other attachment member 56 on the vehicle body upper side is the tire 48a of the spare tire 48. It comes to contact with.

  When the rear floor panel 36 bends due to torsional deformation or the like of the entire vehicle body, these viscoelastic support members 52 cause the rear floor panel due to relative displacement between the rear floor panel portion provided with the viscoelastic support members 52 and the tire portion of the spare tire. It is designed to deform under the force of the panel and spare tire.

  As a modification, two viscoelastic support members 52 may be arranged on the left and right sides in the vehicle width direction and arranged in the vehicle width direction as shown in FIG. A plurality of each may be arranged.

Next, the operation of this embodiment will be described.
In the vehicle body structure of the vehicle according to the present embodiment, the viscoelasticity is arranged in the spare tire house 44 so as to be in contact with the spare tire 48 between the spare tire house 44 and the spare tire 48 of the rear floor panel 36. Since the support member (viscoelastic member) 52 is provided, the deformation energy is absorbed according to the deformation speed of the deformation in the vehicle width direction that occurs in the rear floor panel 36 due to the torsional deformation of the vehicle body that occurs when the vehicle turns. Further, the deformation is allowed to some extent, and the reaction force due to the deformation of the viscoelastic support member works to suppress the deformation of the rear floor panel, thereby increasing the rigidity of the rear floor panel. Therefore, the deformation of the rear floor panel can be suppressed and the torsional deformation of the vehicle body can be suppressed without greatly increasing the rigidity of the rear floor panel 36.

  In particular, the viscoelastic support member 52 is deformed by the relative displacement between the rear floor panel portion on which the viscoelastic support member 52 is provided and the tire portion of the spare tire, and the viscoelastic support member 52 that deforms in the vehicle width direction Therefore, it is possible to effectively suppress the torsional deformation of the vehicle body such that the rear floor panel 36 bends in the vehicle width direction.

The viscoelastic support member 52 has a lower surface 56b of one attachment member 56 on the vehicle body lower side bonded to the bottom 44a of the spare tire house 44, and an upper surface 56a of the other attachment member 56 on the vehicle body upper side. Since the tire 48 abuts on the tire 48a, the torsional deformation of the vehicle body can be effectively suppressed.
The viscoelastic member 52 attenuates vibration transmitted from the suspensions 24 and 30 and the engine 26 to the rear floor panel 36 through the frame member of the vehicle body, thereby reducing acoustic radiation from the rear floor panel 36 and reducing room noise. It can be reduced.

  Therefore, it is possible to prevent the vehicle body structure around the floor, for example, damage due to stress concentration on other members such as the pillars of the vehicle body and spot welding that holds the structural parts of the vehicle body from coming off, while reducing the weight of the vehicle body. Can improve the maneuverability. Moreover, indoor noise can be reduced.

Next, the structure of the rear floor panel of the second embodiment will be described with reference to FIG.
FIG. 6 is an enlarged plan view showing the rear floor panel of the second embodiment. In the present embodiment, as described above, the pair of viscoelastic members 52 are provided on the bottom 44a of the spare tire house 44 of the rear floor panel 36, and further, the wheel support 46 is deformed in the longitudinal direction of the vehicle body in the longitudinal direction. A pair of elastic support members (elastic members) 58 formed of a plate-like elastic body that generates a predetermined reaction force according to the amount is provided. Other configurations are as described above.

  When the spare tire 48 is attached to the wheel support portion 46, the lower surface of the elastic support member 58 is spare so that the upper surface of the elastic support member 58 is in a position and height so as to contact the spare tire 48. It is bonded to the bottom 44a of the tire house.

  These elastic support members 58 have spring characteristics, and a spring mass system is constituted by the spring constant of the elastic support members 58 and the weight of the spare tire 48 in contact with the elastic support members. It functions as a dynamic damper in the vicinity of 20 Hz (about 15 Hz to 25 Hz) which is the resonance frequency of the bending vibration in the longitudinal direction (so-called secondary vibration of the vehicle body).

Next, the operation of this embodiment will be described. In the present embodiment, as described above in the first embodiment, the viscoelastic member 52 can suppress deformation in the vehicle width direction that occurs in the rear floor panel 36.
In the present embodiment, the elastic member 58 is provided in the spare tire house 44 so as to be arranged in the front-rear direction of the vehicle body so as to contact the spare tire 48 between the spare tire house 44 and the spare tire 48 of the rear floor panel 36. Since these elastic members 58 function as dynamic dampers at the resonance frequency of bending vibration in the longitudinal direction of the entire vehicle body (so-called secondary vibration of the vehicle body), bending vibration in the longitudinal direction of the entire vehicle body Can be suppressed, noise in the vehicle interior due to acoustic radiation of the bending vibration can be reduced, and the operability of the vehicle can be improved.

  Furthermore, the positions of the viscoelastic members 52 provided on the left and right sides of the wheel support portion in the vehicle width direction are substantially in the middle of the pair of elastic members 58 provided in the vehicle body longitudinal direction. Since they are arranged as far apart as possible, it is possible to prevent deformation of the elastic member 58 acting as a dynamic damper.

It is a perspective view which shows the underbody of the vehicle body which has the vehicle body structure of the vehicle by 1st Embodiment of this invention. It is a top view which expands and shows the rear floor panel of FIG. It is sectional drawing seen along the III-III line of FIG. It is a perspective view which shows the viscoelastic member applied to 1st Embodiment of this invention. It is a top view which expands and shows the rear floor panel by the modification of 1st Embodiment of this invention. It is a top view which expands and shows the rear floor panel by 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Underbody body 36 of a vehicle body Rear floor panel 44 Spare tire house 46 Wheel support part 48 Spare tire 50 Elastic pad 52 Viscoelastic support member 54 Viscoelastic body 56 Mounting member 58 Elastic support member

Claims (3)

A vehicle body structure for storing a spare tire in a recess formed in a rear floor panel of a vehicle body,
A plurality of viscoelastic members provided in contact with the spare tire and arranged in the vehicle width direction between the recess of the rear floor panel and the spare tire;
A vehicle body structure for a vehicle, characterized in that these viscoelastic members receive a force from the recess of the rear floor panel and a spare tire to generate a predetermined viscous damping force. Furthermore, it has a plurality of elastic members provided so as to abut on the spare tire between the recess of the rear floor panel and the spare tire and to be arranged in the longitudinal direction of the vehicle body,
The vehicle body structure according to claim 1, wherein the elastic member has a spring characteristic that functions as a dynamic damper at a predetermined frequency together with the spare tire.   The viscoelastic member includes a plate-like viscoelastic body and a pair of plate-like attachment members respectively provided on the upper and lower surfaces of the viscoelastic body, and the attachment member provided on the lower surface is provided in the rear floor panel recess. The vehicle body structure according to claim 1, wherein an attachment member fixed to the upper surface and affixed to an upper surface of the mounting member abuts against a tire of the spare tire.

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