JP2005047363A - Frame coupling structure of vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a frame coupling structure of a vehicle where a power train is mounted capable of suppressing effectively the vibration of a frame and enhancing the sound communication performance. <P>SOLUTION: The frame coupling structure of the vehicle is structured so that a front side member 2 is coupled by a rod 13L (13R) with a sub-frame 7 where the power train 6 is mounted, wherein an upper resilient piece 14L (14R) and a lower resilient piece 15L (15R) are interposed between the rod 13L (13R) and the sub-frame 7 and the front side member 2, and the rigidity of the upper resilient piece 14L (14R) is made smaller than that of the lower resilient piece 15L (15R), and thereby the rod 13L (13R) and the lower resilient piece 15L (15R) are allowed to serve as a dynamic damper 16L (16R). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a frame connecting structure on which a power train is mounted.

Conventionally, as this type of vehicle frame connection structure, for example, a front side member and a cross beam frame disposed below the front side member are provided with a slight relative to each other for the purpose of suppressing deformation of the passenger compartment at the time of a forward collision. There is a front body structure of an automobile that is connected by a restraining member that allows displacement and prevents large relative displacement (see Patent Document 1).
In addition, the front side member and the cross beam frame are fastened by a connecting member, and when the load at the time of a front collision exceeds a set value, the connecting member is broken and the front side member and the cross beam frame are bent and deformed in the vertical direction, respectively. There is a front vehicle body structure of an automobile which is configured as described above to improve impact absorption characteristics (see Patent Document 2).
Japanese Patent Laid-Open No. 10-264862 JP 2002-240738 A

However, in the conventional example described in Patent Document 1, since both are simply connected by a restraining member that allows slight relative displacement between the front side member and the cross beam frame, There is an unsolved problem that the vibration of the cross beam frame excited by the vibration input cannot be suppressed and the sound vibration performance is low.
Further, in the conventional example described in Patent Document 2, since the front side member and the cross beam frame are only fastened by the connecting member, vibration from the power train is transmitted to the front side member via the cross beam frame. There is an unsolved problem of being transmitted directly.
Therefore, the present invention has been made paying attention to the unsolved problems of the above-described conventional example, and can effectively suppress vibration of the frame on which the power train is mounted and improve the sound performance. It aims to provide a connecting structure.

  To achieve the above object, a vehicle frame connection structure according to the present invention connects a first frame on which a power train is mounted and a second frame facing the first frame with a connecting member. In this case, an elastic body is interposed between the connecting member and each of the first frame and the second frame, and the rigidity of the elastic body on the second frame side is determined by the rigidity of the elastic body on the first frame side. It is characterized by being made smaller.

  According to the vehicle frame connection structure of the present invention, when connecting the first frame on which the power train is mounted and the second frame facing the first frame with the connection member, the connection member and the second frame are connected. Since the elastic body is interposed between each of the first frame and the second frame, the rigidity of the elastic body on the second frame side is made smaller than the rigidity of the elastic body on the first frame side. When the first frame whose vibration is excited by the vibration input from the main frame is used as the main vibration system, the connecting member and the elastic body on the first frame side are the sub-vibration system, that is, the dynamic damper using the connecting member as a mass. Therefore, the vibration of the first frame can be effectively suppressed and the sound vibration performance can be improved.

Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram showing a first embodiment when the present invention is applied to a front engine type vehicle. The vehicle body 1 is provided with a front side member 2 as a second frame extending in the front-rear direction on both the left and right sides. The rear side of the vehicle body 1 is bent downward at the lower part of the dash panel 3 and substantially along the floor panel 4. It is connected to a floor side member 5 that extends horizontally. Below the front side member 2, a sub-frame 7 is disposed as a first frame on which a power train 6 composed of an engine and a transmission is mounted.

  As shown in FIG. 2, the sub-frame 7 includes left and right side frames 8L and 8R facing the side member 2, a front frame 9 that joins the front ends thereof, and a rear frame 10 that joins the rear ends. It is shaped like a cross. The sub-frame 4 is elastically supported by the front side member 2 via the front insulators 11L and 11R and the rear insulators 12L and 12R as elastic support members disposed at the four corners. Further, as shown in FIG. 1, the left and right side frames 8L and 8R are connected to the front side member 2 by connecting rods 13L and 13R as connecting members, respectively.

In order to prevent vibration from the power train from being transmitted to the front side member 2 via the connecting rod 13L (13R) between the front side member 2 and the side frame 8L (8R) A body 14L (14R) and a lower elastic body 15L (15R) are interposed.
The upper elastic body 14L (14R) is set so as to be less rigid than the lower elastic body 15L (15R), that is, softer. Thereby, when the sub-frame 7 in which vibration is excited by the vibration input from the power train 6 is used as the main vibration system, the connecting rod 13L (13R) and the lower elastic body 15L (15R) are connected to the connecting rod 13L. Since it functions as a sub-vibration system having (13R) as a mass, that is, a dynamic damper 16L (16R), vibration of the sub-frame 7 can be effectively suppressed.

  At this time, since the connecting rod 13L (13R) vibrates relatively large, the rigidity and size of the upper elastic body 14L (14R) are set so that vibration transmission to the front side member 2 can be sufficiently suppressed. When it is desired to effectively suppress the vibration of the sub-frame 7 in a specific frequency region, the mass of the connecting rod 13L (13R) as a mass and the rigidity of the lower elastic body 15L (15R) are adjusted. The characteristic value of the resonance frequency in the dynamic damper 16L (16R) is set as appropriate.

As a result, as shown in FIG. 3, the vibration suppression effect is exhibited in a specific frequency region (here, the frequency region corresponding to the vertical vibration mode of the subframe 7), and the sound pressure level in the passenger compartment is reliably reduced. be able to.
Further, if the eigenvalues of the resonance frequency are made different between the left dynamic damper 16L and the right dynamic damper 16R, as shown in FIG. 4, two frequency regions (here, the vertical vibration mode and the bending vibration mode of the subframe 7). In the frequency region corresponding to the above, the vibration suppression effect can be exhibited, and the sound pressure level in the passenger compartment can be reliably reduced.

  As described above, according to the first embodiment, the upper elastic body 14L (14R) and the lower elastic body 15L (15R) are provided between the connecting rod 13L (13R), the front side member 2, and the subframe 4, respectively. Since the rigidity of the upper elastic body 14L (14R) is smaller than the rigidity of the lower elastic body 15L (15R), the connecting rod 13L (13R) and the lower elastic body 15L (15R) are dynamic. Acting as a damper 16L (16R), the vibration of the sub-frame 4 can be effectively suppressed, and the sound vibration performance can be improved.

In addition, the connecting rod 13L (13R) and the lower elastic body 15L (15R) form a plurality of dynamic dampers 16L (16R) having different resonance frequency eigenvalues, thereby enabling the vibration of the subframe 7 to be suppressed. The area can be expanded.
In the first embodiment, the case where the present invention is applied to a front engine type vehicle has been described. However, the present invention is not limited to this and may be applied to a rear engine type vehicle.

Next, 2nd Embodiment of this invention is described based on FIGS.
In the second embodiment, the pitch axis of the pitch vibration generated in the subframe 7 and the connecting position of the connecting rod 13L (13R) in the side frame 8L (8R) are separated from the first embodiment described above. It is.
First, as shown in FIG. 5A, the connecting position of the connecting rod 13L (13R) is moved forward from the pitch axis of the pitch vibration generated in the subframe 7, or as shown in FIG. 5B. The pitch vibration of the sub-frame 7 can be more effectively suppressed by moving it away from the pitch axis.

As a result, as shown in FIG. 6, both the embodiment (a) in which the connecting position is separated from the pitch axis forward and the embodiment (b) in which the connecting position is separated rearward from the pitch axis, The vibration suppression effect can be exhibited in the frequency region corresponding to the vibration mode, and the sound pressure level in the passenger compartment can be reliably reduced.
Further, the connecting positions of the left and right connecting rods 13L and 13R may be separated from the pitch axis in the opposite direction. That is, as shown in FIG. 5C, if the left connecting rod 13L is separated backward from the pitch axis and the right connecting rod 13R is separated forward from the pitch axis, the pitch vibration of the subframe 7 is further increased. In addition to being able to be effectively suppressed, as shown in FIG. 7, the excitation of pitch vibration itself can be suppressed by the pitch axis being inclined in the front-rear direction and the pitch rigid body mode being destroyed.

As a result, as shown in FIG. 6, in the embodiment (c) in which the left and right connecting positions are separated from the pitch axis in the opposite directions, the pitch of the subframe 7 is larger than in the embodiments (a) and (b). A greater vibration suppression effect can be exhibited in the frequency region corresponding to the vibration mode, and the sound pressure level in the passenger compartment can be further reduced.
Further, the front insulator 11L (11R) and the rear insulator are arranged such that the pitch axis when the pitch vibration is generated in the subframe 7 is separated from the connecting position between the side frame 8L (8R) and the connecting rod 13L (13R). The rigidity may be adjusted to 12L (12R). That is, as shown in FIG. 8, if the rigidity of the front insulator 11L (11R) is set to be smaller than the rigidity of the rear insulator 12L (12R), the rear side is a fixed end and the front side is a free end. Since the pitch axis of the frame 7 is shifted forward from substantially the center, the pitch axis of the subframe 7 is separated from the connection point, and the pitch vibration of the subframe 7 can be more effectively suppressed.

Also in this case, as shown in FIG. 9, the vibration suppressing effect can be exhibited in the frequency region corresponding to the pitch vibration mode of the subframe 7, and the sound pressure level in the passenger compartment can be reliably reduced.
Next, a third embodiment of the present invention will be described with reference to FIGS.
In the third embodiment, the shape of the connecting rod 13L (13R) is changed in the first embodiment described above. That is, in the third embodiment, as shown in FIG. 10, the connecting rod 13L (13R) has its center of gravity G separated from the straight line connecting the front side member 2 and the side frames 8L and 8R. Formed.

As a result, the connecting rod 13L (13R) has a vertical rigid body mode and a rotating rigid body mode as shown in FIG. 11 with respect to the vibration of the sub-frame 7, so that the frequency region in which the vibration suppressing effect can be exhibited. Can be increased.
As a result, as shown in FIG. 12, the vibration suppressing effect is exhibited in a wide frequency range (here, the frequency range corresponding to the vertical vibration mode, roll vibration mode, longitudinal vibration mode, and bending vibration mode of the subframe 7). This can reliably reduce the sound pressure level in the passenger compartment.

It is a schematic structure figure showing a 1st embodiment of the present invention. 3 is a schematic view of a subframe 7. It is a graph which shows the effect of a 1st embodiment. It is a graph which shows the effect at the time of providing two dynamic dampers from which the natural value of resonance frequency differs. It is a schematic block diagram of 2nd Embodiment which spaced apart the connection position from the pitch axis. It is a graph which shows the effect of 2nd Embodiment which made the connection position spaced apart from the pitch axis. It is a figure explaining the inclination of a pitch axis. It is a schematic block diagram of 2nd Embodiment which spaced apart the pitch axis from the connection position. It is a graph which shows the effect of a 2nd embodiment which spaced apart the pitch axis from the connecting position. It is an enlarged view of the connecting rod in 3rd Embodiment. It is a figure explaining the rigid body mode of a connecting rod. It is a graph which shows the effect of a 3rd embodiment.

Explanation of symbols

2. Front side member (second frame)
6 ... Powertrain 7 ... Subframe (first frame)
8L, 8R ... side frame 11L, 11R ... front insulator (front elastic support member)
12L, 12R: Rear insulator (rear elastic support member)
13L, 13R ... Connecting rod (connecting member)
14L, 14R: Upper elastic body 15L, 15R: Lower elastic body 16L, 16R: Dynamic damper (sub vibration system)

Claims (6)

In a vehicle frame connection structure in which a first frame on which a power train is mounted and a second frame facing the first frame are connected by a connecting member,
An elastic body is interposed between the connecting member and each of the first frame and the second frame, and the rigidity of the elastic body on the second frame side is determined by the elastic body on the first frame side. A vehicle frame connection structure characterized by being smaller than the rigidity of the vehicle.   The coupling member and the elastic body on the first frame side form a plurality of sub-vibration systems having different resonance frequency eigenvalues, and the plurality of sub-vibration systems are arranged between the first and second frames. The vehicle frame connection structure according to claim 1, wherein the vehicle frame connection structure is provided.   The vehicle frame connection structure according to claim 1, wherein the connection member is connected to a position away from a pitch axis when pitch vibration is generated in the first frame.   The said connection member is connected to two places of the vehicle width direction both ends of the said 1st flame | frame, The said 2 connection member was respectively spaced apart from the said pitch axis in the reverse direction. Frame connection structure for vehicles.   A plurality of elastically supporting the first frame on the vehicle body side so that a pitch axis when pitch vibration is generated in the first frame is separated from a connection position between the first frame and the connecting member. The vehicle frame connection structure according to claim 1, wherein rigidity of the elastic support member is set.   6. The connecting member according to claim 1, wherein the connecting member is formed such that the center of gravity of the connecting member is separated from a straight line connecting the connecting points of the first and second frames. Frame connection structure for vehicles.

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