Front vehicle-body structure of vehicle

Patent metadata

Field	Value
Publication number	US-9254872-B2
Application number	US-201414191240-A
Country	US
Kind code	B2
Filing date	Feb 26, 2014
Priority date	Mar 5, 2013
Publication date	Feb 9, 2016
Grant date	Feb 9, 2016

Abstract

A longitudinal member is configured to transmit a part of a collision load occurring in a vehicle head-on collision to a suspension cross member by way of a front portion, a bending portion, and a rear portion. A lower arm, a portion of which is co-fastened to a vehicle body together with a fastening portion, is configured to transmit another part of the collision load occurring in the vehicle head-on collision to the fastening portion from the front portion. Accordingly, the rear end of the sub frame can be properly detached from the vehicle body in the vehicle head-on collision even in a case in which any weak portion extending in a vehicle width direction may not be provided.

First claim

What is claimed is:

1. A front vehicle-body structure of a vehicle, comprising
a pair of right-and-left front side frames extending substantially in a vehicle longitudinal direction at a front portion the vehicle; and
a sub frame provided below the front side frames and supporting a pair of right-and-left suspension lower arms which constitute part of a vehicle suspension,
wherein said sub frame comprises a sub-frame body portion extending substantially in a vehicle width direction, a pair of right-and-left extension portions extending forward from the sub-frame body portion below the side frames, and a pair of right-and-left fastening portions projecting outward, in the vehicle width direction, from a rear end of the sub-frame body portion,
each of said extension portions of the sub frame comprises a front portion extending substantially in the vehicle longitudinal direction, a bending portion bending slightly inward at a rear end of the front portion, and a rear portion provided rearward from the bending portion so as to extend obliquely inward relative to the vehicle longitudinal direction,
said sub frame is configured to be fastened to a vehicle body at least via said fastening portions by means of a fastening member including bolt and nut, each of the fastening portions having a bolt hole into which the bolt of the fastening member is inserted,
each of said suspension lower arms is arranged in back of said front portion, on an outward side of said rear portion of the extension portion of the sub frame, and in front of said fastening portion of the sub frame, a front end of said suspension lower arm is supported at the extension portion of the sub frame by means of a supporting member, and a rear end of said suspension lower arm is supported at the fastening portion of the sub frame by means of another supporting member, and
said bolt and nut of the fastening member for fastening the fastening portions of the sub frame to the vehicle body are commonly used as part of said another supporting member for supporting the rear end of the suspension lower arm such that the rear end of the suspension lower arm is co-fastened to the vehicle body together with the fastening portions of the sub frame by means of said bolt and nut, and said bolt hole of the fastening portion is located on an outward side, in the vehicle width direction, relative to a side end face of the sub-frame body portion, whereby a collision load occurring in a vehicle head-on collision is transmitted to the fastening portion from the extension portion by way of the sub-frame body portion and part of said collision load is transmitted to the fastening portion from the extension portion by way of the suspension lower arm, bypassing the sub-frame body portion.

2. The front vehicle-body structure of a vehicle of claim 1 , wherein each of said pair of right-and-left fastening portions of the sub frame has an opening portion where forward and outward sides of the fastening portion are open and a rearward side of the fastening portion is closed.

3. The front vehicle-body structure of a vehicle of claim 2 , wherein said rear end of the suspension lower arm is supported at said opening portion of the fastening portion of the sub frame so as to be arranged in an inner space of the fastening portion which is formed by an upper member and a lower member of the fastening portion.

4. The front vehicle-body structure of a vehicle of claim 3 , wherein said another supporting member includes an outer tube to which the rear end of the suspension lower arm is fixed, an inner tube which has a tubular central axis extending substantially in a vehicle vertical direction and is arranged in said inner space of the fastening portion so as to contact inside faces of the upper and lower members of the fastening portion of the sub frame at upper and lower ends thereof, respectively, and a rubber member arranged between the inner tube and the outer tube, and
said bolt of the fastening member is configured to be inserted into said inner tube, extending substantially in the vehicle vertical direction, and said nut of the fastening member is configured to be fixed to said vehicle body,
whereby the inner tube of said another supporting member provided at the rear end of the suspension lower arm is co-fastened to the vehicle body together with the fastening portion of the sub frame by means of said bolt and nut fastened to each other.

5. The front vehicle-body structure of a vehicle of claim 2 , wherein said sub-frame body portion of the sub frame is formed in a hollow shape so as to have an upper face portion thereof, a lower face portion thereof, and a side face portion thereof, and
said pair of fastening portions of the sub frame are configured to project outward from the rear end of the sub-frame body portion such that respective inward ends of said opening portions thereof are located at positions corresponding to respective rear ends of said side portion which extend substantially in the vehicle longitudinal direction.

6. The front vehicle-body structure of a vehicle of claim 5 , wherein a low rigidity portion is formed at said sub frame, which is caused by a difference in rigidity which is created by an existence of said side face portion of the side-frame body portion and said opening portion of the fastening portion, and said low rigidity portion of the sub frame is arranged within an area defined between an imaginary line which interconnects a position around a support point of the front end of the suspension lower arm at the extension portion of the sub frame and said fastening portion of the sub frame and another imaginary line which extends along an extension direction of said rear portion of the extension portion of the sub frame.

7. The front vehicle-body structure of a vehicle of claim 1 , wherein a low rigidity portion which has a relatively low rigidity is formed at said sub frame, and said low rigidity portion of the sub frame is arranged within an area defined between an imaginary line which interconnects a position around a support point of the front end of the suspension lower arm at the extension portion of the sub frame and said fastening portion of the sub frame and another imaginary line which extends along an extension direction of said rear portion of the extension portion of the sub frame.

Assignees

• Mazda Motor

Inventors

• Otani Takahiro
• Sasage Kohtaro
• Hibino Nobuhiko
• Ishikawa Yasushi
• Kanemoto Shunsuke

Classifications

• B62D21/155 Primary

  Sub-frames or underguards · CPC title