JPS62139765A - Bulkhead for vehicle - Google Patents

Abstract

PURPOSE:To reduce noise in the passenger's compartment of a vehicle, and to enhance the drive comfortability of the vehicle during traveling on a road in a bad condition, by forming reinforcing members projecting from the surfaces of a beam in a frame system of a vehicle body, and by disposing a viscoelastic material between a plurality of the reinforcing members. CONSTITUTION:In a hollow beam 10 in a frame system of a vehicle, L-like reinforcing members 18, 20 are welded respectively to side walls 12, 14 whose inner surfaces are opposed to each other, so that the members 18, 20 are overlapped with each other having a slight gap between their free end parts. Further, a viscoelastic material 22 is disposed between the overlapped parts of the members 18, 20. The viscoelastic material 22 is the one such as asphalt, butyl rubber, vinyl acetate or the like, which has the absolute value of a complex spring constant that is low for low frequency vibration but high for high frequency vibration. With this arrangement it is possible to enhance the rigidity of the reinforcing members against high frequency vibration such as engine vibration and to reduce the transmission of low frequency vibration caused during a vehicle traveling on a road in a bad condition, toward the floor of the vehicle body.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a bulkhead for a vehicle that reinforces beams in the skeletal system of a vehicle body. The noise is transmitted into the vehicle interior via the beams, causing interior noise.

In order to reduce this noise, the beam 10 is reinforced by bridging the bulkhead 16 on the inner surface side 1t2.14 of the hollow beam 10, as shown in Figure t53. As a result, deformation of the cross-sectional shape of the beam due to engine vibration is reduced, and the vibration characteristics of the beam IO are improved. However, the part reinforced by the bulkhead 16 is the underbody part that mainly affects the ride comfort, and the reinforcement makes it easier for low-frequency vibrations when driving on rough roads to be directly transmitted to the undercarriage part, so the ride comfort is reduced. will decrease.

SUMMARY OF THE INVENTION An object of the present invention is to provide a bulkhead for a vehicle that can reduce in-vehicle noise caused by engine vibration and does not reduce ride comfort when driving on rough roads.

[Means for Solving the Problems] In the vehicle bulkhead according to the present invention, there is a reinforcing member that protrudes toward the surface of the beam, and a reinforcing member that is interposed between a plurality of reinforcing members and fixed to the reinforcing member. It has a viscoelastic member.

[Function] The absolute value of the complex spring constant of a viscoelastic member is small for low frequency vibrations and large for high frequency vibrations. Therefore, the rigidity of the viscoelastic member is small for high frequency vibrations such as engine vibrations. becomes larger and the beam is reinforced in the same way as when no viscoelastic member is used, so the noise inside the car is reduced. Furthermore, with respect to low-frequency vibrations when driving on rough roads, the reinforcing effect is reduced due to the spring properties of the viscoelastic member, and the transmission of low-frequency vibrations to the floor is softened.

[Example] An example of a vehicle bulkhead according to the present invention will be described with reference to the drawings.

FIG. 11 shows a partial longitudinal section of a beam 10 of the frame system of a vehicle body, in which L-shaped reinforcing members 18.degree. The distal ends of the reinforcing members 18,20 are slightly spaced apart and overlap. Reinforcing members 18 and 2 of this overlapping part
Between 0.

A viscoelastic member 22 is interposed. One side of the viscoelastic member 22 is bonded to the reinforcing member 20, and the viscoelastic member 2
The other side of 2 is bonded to the reinforcing member 18.

The viscoelastic member 22 has a complex spring constant whose absolute value is small for low frequency vibrations and large for high and low frequency vibrations, and is made of a substance such as asphalt, butyl rubber, or vinyl acetate.

Next, the operation of this embodiment configured as described above will be explained.

When high frequency vibrations such as engine vibrations are transmitted through the beam 10, the absolute value of the complex spring constant of the viscoelastic member 22 becomes large, and the rigidity of the viscoelastic member 22 becomes high. For this reason,
This is similar to the case where the reinforcing member 18 and the reinforcing member 20 are directly welded, and transmission of engine vibrations into the vehicle interior can be reduced, and vehicle interior noise can be reduced.

Furthermore, with respect to low-frequency vibrations that occur when driving on rough roads, the absolute value of the complex spring constant of the viscoelastic member 22 is small, so the reinforcing effect by the reinforcing members 18 and 20 is reduced due to the elasticity of the viscoelastic member 22. Therefore, the rigidity of the beam IO is reduced, and transmission of low frequency vibrations to the floor of the vehicle body can be reduced.

Next, a second embodiment of the present invention will be described with reference to FIG.

In this second embodiment, in addition to the configuration shown in FIG. 1, viscoelastic members 24.26 similar to the viscoelastic member 22 are bonded to the side surfaces of the reinforcing member 18.20. Also, the side wall 12.14
A reinforcing member 28, 30 similar to the reinforcing members 18, 20 is welded to. The side surface of the viscoelastic member 26 is a reinforcing member 28
The side surface of the viscoelastic member 24 is bonded to the side surface of the reinforcing member 3.
It is glued to the side of 0.

In this p52 embodiment, the overall complex spring constant of the viscoelastic members 22, 24, 26 is three times that of the first embodiment. Therefore, it is effective when the absolute value of the complex spring of the viscoelastic member is small.

Note that the structure may be such that the reinforcing member 28 and the viscoelastic member 26 or the viscoelastic member 24 and the reinforcing member 30 are not provided, or the structure may be such that four or more layers of viscoelastic members are provided. The mounting surfaces of the beams may be adjacent surfaces instead of opposing surfaces of the beams.Furthermore, the beams may be channel-shaped.

[Effects of the Invention] In the vehicle bulkhead according to the present invention, a reinforcing member is provided protruding from the surface of the beam, and a viscoelastic member is interposed between the plurality of reinforcing members and is fixed to the reinforcing member. As a result, the stiffness of the reinforcing member is high against high-frequency vibrations such as engine vibration, which increases the stiffness of the beam and reduces the transmission of engine vibration into the cabin, reducing cabin noise. can be reduced. Additionally, due to the elasticity of the viscoelastic member, the reinforcing effect of the reinforcing member is reduced against low-frequency vibrations that occur when driving on rough roads, which reduces the rigidity of the beam and causes low-frequency vibrations to be directly transmitted to the floor of the vehicle. It has the excellent effect of reducing the

[Brief explanation of drawings]

Fig. 1 is a vertical cross-sectional view of a hollow beam of a first embodiment to which the present invention is applied, ptS2 is a longitudinal cross-sectional view of a hollow beam of a second embodiment, t
FIG. 53 is a vertical cross-sectional view of a hollow beam showing a conventional example. 10e1...beam, 12.14----side wall, 18.20.28.30...1 reinforcing member 22, 24.
26.--- Viscoelastic member.

Claims (1)

[Claims] A bulkhead for a vehicle, comprising: a reinforcing member protruding toward a surface of a beam; and a viscoelastic member interposed between a plurality of the reinforcing members and fixed to the reinforcing member.