JP4608523B2 - Engine mount mounting structure - Google Patents

Description

  The present invention relates to an engine mount mounting structure, and more particularly to a technique for improving engine support rigidity while suppressing the complexity of a vehicle body structure and an increase in vehicle body weight.

An automobile having a monocoque structure (hereinafter referred to as a monocoque car) has a body produced by press-molding a thin steel plate to produce a large number of body panels and skeletal members and then joining them by spot welding or the like. Usually, in an automobile in which the engine is mounted on the front part of the vehicle body, the engine is supported on the left and right front side frames, which are skeleton members, via an engine mount made of an elastic body such as rubber. The engine mount is fastened to the front side frame with bolts, but if its support rigidity is insufficient, NVH (noise, vibration, harshness) performance is degraded. Therefore, the present applicant has an engine mount mounting structure in which a pair of front and rear partition walls are arranged in a closed cross section (rectangular cross section) of the front side frame, and nuts for fastening the engine mount are welded / integrated to these partition walls. Proposed in the past (see Patent Document 1).
JP 2006-2119068 A

  Since the structure of Patent Document 1 described above can support the engine with high support rigidity, it can achieve a significant improvement in NVH performance in a medium-sized vehicle or the like, but further improvement has been demanded when applied to a small vehicle. That is, in Patent Document 1, since the pair of left and right engine mounts are fastened to the front side frame by two front and rear bolts, the support rigidity of the engine mount (that is, the engine) is low in a small vehicle where the rigidity of the front side frame itself is small. Thus, sufficient NVH performance cannot be secured. As a method for improving the support rigidity, for example, it is conceivable to fasten the engine mount to the upper surface of the front side frame with three bolts, but this is also difficult to apply to a small vehicle having a small front side frame width.

  For this reason, in a conventional small vehicle, an engine mount fastening portion (third engine mount fastening portion) is further installed on the damper housing side of the front side frame, and the engine is supported by a total of three engine mount fastening portions. It was done. However, it is difficult to install the third engine mount fastening part between the headlight and the wheel house in a small car with a large headlight and a front windshield that has been advanced, only increasing the number of parts and the number of assembly steps. In addition, the degree of freedom in design was also reduced.

  The present invention has been made in view of such a background, and an object of the present invention is to provide an engine mount mounting structure that realizes improvement in engine support rigidity while suppressing the complexity of the vehicle body structure and the increase in the vehicle body weight. To do.

  The invention according to claim 1 is a structure in which an engine mount is attached to a pair of left and right front side frames, and the front side frame has either a closed cross-section with a flat upper surface and an inner wall or an outer wall from the upper wall of the closed cross-section. A horizontal flange extending on one side, and installed on the upper wall of the closed cross-sectional portion so as to be separated from each other in the front-rear direction, the first and second fastening portions to which the engine mount is fastened, and the horizontal flange And a third fastening portion to which the engine mount is fastened, and a straight line connecting the first to third fastening portions forms a triangle.

  According to the invention of claim 1, even if the width of the closed cross section of the front side frame is relatively small, for example, the engine mount can be fastened with three bolts by providing the third fastening portion on the horizontal flange. The support rigidity of the engine mount (that is, the engine) is improved, and high NVH performance can be realized.

  Hereinafter, an embodiment of a vehicle body structure to which the present invention is applied will be described in detail with reference to the drawings. FIG. 1 is a perspective view showing a vehicle body skeleton structure according to the embodiment, FIG. 2 is a perspective view showing an engine mount mounting structure according to the embodiment, and FIG. 3 is a longitudinal sectional view of a main part of a front side frame according to the embodiment. FIG. 4 is a perspective view of a main part of the front side frame outer according to the embodiment.

<< Configuration of Embodiment >>
In this embodiment, the present invention is applied to the body of a four-door hatchback type passenger car.
As shown in FIG. 1, the body 1 of the embodiment has a pair of left and right front sides extending substantially in parallel from both ends of the front bumper beam 2 toward the lower ends of the left and right damper housings 3 and 4 as the skeleton members. Frames 5 and 6 are provided. A power unit 8 in which the engine and the transmission are integrated is mounted in the engine room 7, and the power unit 8 is supported by the left and right front side frames 5 and 6 via a pair of left and right engine mounts 11 and 12.

  Hereinafter, the attachment form and structure of the right engine mount 12 and the front side frame 6 will be described.

  As shown in FIG. 2, the right engine mount 12 is fastened to the upper surface of the right front side frame 6 by three bolts 13. The right front side frame 6 is provided with first and second screw holes (fastening portions) 21 and 22 spaced from each other on the left and right sides, and a third rear side of the first and second screw holes 21 and 22. A screw hole (fastening portion) 23 is provided, and each bolt 13 is screwed into the first to third screw holes 21 to 23. The first to third screw holes 21 to 23 are arranged so that straight lines connecting each other form a triangle T (that is, do not exist on a straight line).

  As shown in FIG. 3, the right front side frame 6 is formed by integrating a frame inner 31 forming an inner portion and a frame outer 32 forming an outer portion by spot welding. The right front side frame 6 has a closed section 33 defined by the frame inner 31 and the frame outer 32, and a horizontal flange 34 extending outward from the upper wall of the closed section 33. Yes.

  As shown in FIG. 4, a pair of front and rear stiffeners 35 and 36 that connect the frame inner 31 and the frame outer 32 are mounted in the closed cross-section 33 in the vicinity of the attachment site of the right engine mount 12. Nuts 37 for forming the first and third screw holes 21 and 23 are welded / integrated with the stiffeners 35 and 36. Further, as shown in FIG. 3, a nut 38 that forms the second screw hole 22 is welded / integrated to the lower surface of the horizontal flange 34.

<< Operation of Embodiment >>
When the vehicle starts running, the power unit 8 is subjected to an excitation force accompanying the movement of the vehicle body, and stresses in various directions are generated at the attachment portions of the engine mounts 11 and 12 to the front side frames 5 and 6. Of course, in this embodiment, the engine mounts 11 and 12 are fastened to the front side frames 5 and 6 by three bolts 13 and the first to third screw holes 21 to which the three bolts 13 are screwed. 23 is arranged so that the straight line connecting each other forms a triangle T, the power unit 8 is supported with high support rigidity without using a third engine mount or the like that increases the weight and the number of parts. Thereby, high NVH performance can be realized.

  Although the description of the specific embodiment is finished as described above, the present invention is not limited to the above embodiment and can be widely modified. For example, in the above embodiment, the present invention is applied to a four-door hatchback type passenger car, but the present invention may be applied to other automobiles such as a two-door automobile. Moreover, as a fastening part provided in a front side frame, it may replace with a screw hole and may employ | adopt a stud bolt. In addition, the specific shape and the like of the front side frame and the like can be changed as appropriate without departing from the spirit of the present invention.

1 is a perspective view showing a vehicle body skeleton structure according to an embodiment. It is a perspective view which shows the attachment structure of the engine mount which concerns on embodiment. It is a principal part longitudinal cross-sectional view of the front side frame which concerns on embodiment. It is a principal part perspective view of the front side frame outer which concerns on embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Body 5 Left front side frame 6 Right front side frame 8 Power unit 11 Left engine mount 12 Right engine mount 13 Bolt 21 1st screw hole (fastening part)
22 Second screw hole (fastening part)
23 Third screw hole (fastening part)
31 Frame inner 32 Frame outer 33 Closed section 34 Horizontal flange 35 Stiffener 37 Nut 38 Nut T Triangle

Claims (1)

The engine mount is attached to a pair of left and right front side frames,
The front side frame has a closed cross-section portion whose upper surface is flat, and a horizontal flange extending from the upper wall of the closed cross-section portion to either the inside or the outside,
First and second fastening portions installed on the upper wall of the closed cross-sectional portion so as to be separated from each other in the front-rear direction, and to which the engine mount is fastened;
A third fastening portion installed on the horizontal flange and fastened to the engine mount;
A mounting structure for an engine mount, wherein a straight line connecting the first to third fastening portions forms a triangle.

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