JPS63269721A - Power plant frame structure for vehicle - Google Patents

Abstract

PURPOSE:To make torque absorbable by forming an intermediate part of a flange part extending in the horizontal direction of a power plant frame into narrowness, in case of the power plant frame which connects an engine transmission case to a differential. CONSTITUTION:The engine transmission unit 1 mounted at the front side of an automobile is connected to the differential 8 mounted at the rear side of the automobile via a drive shaft 9 and a power plant frame 16. And, this frame 16 has a pair of flange parts 16b and 16c extending in the horizontal direction each to both upper and lower ends of a vertical piece 16a, while it is formed into a sectional U-shaped form having an opening in the horizontal direction. In this constitution, the lower flange 16c is formed into narrowness at the longitudinal intermediate part of a car body. With this constitution, torque to be produced when driving force is transmitted to the differential 8 from the unit 1 is absorbed at the narrow part.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to the structure of a vehicle power plant frame configured to connect a front-mounted engine/mission unit and a rear-mounted differential.

(Prior art) In recent years, a front-mounted engine unit and a rear-mounted differential are firmly connected via a power plant frame with a U-shaped cross section that has high bending rigidity and is flexible against torsion. A system has been developed that aims to reduce engine vibration and suppress differential wind-up vibration caused by torque reaction force from the rear wheels (for example, Japanese Patent Laid-Open No. 56-28053
(see publication).

(Problems to be Solved by the Invention) As described above, in the case of the engine configuration in which the engine transmission unit and the differential are firmly connected by the power plant frame, the power plant frame has the following:
Bending moments due to wind-up vibration of the differential that occur while the car is running and torsional forces caused by the transmission of engine driving force to the differential act.In order to cope with these bending moments and torsional forces, the cross section of the power plant frame is is approximately U-shaped, but in order to cope with bending moments, it is desirable to make the flange part of the power plant frame wide. On the other hand, in order to cope with torsional force, it is desirable to make the flange part narrow. Therefore, mutually contradictory configurations are required. Therefore, if the power plant frame is configured to have the same cross section over its entire length in the longitudinal direction, it will not be possible to satisfy both of the above requirements.
Further improvements are needed.

The present invention has been made in view of the above points, and provides a power plant frame with sufficient rigidity to withstand bending moments caused by wind-up vibrations and sufficient flexibility to absorb torsional forces caused by engine drive force transmission. The purpose of this is to have both gender and gender.

(Means for Solving the Problems) In the present invention, as a means for solving the above problems, a power transmission unit having a substantially U-shaped cross section that connects a front-mounted engine/mission unit and a rear-mounted differential is provided. In the plant frame, one of the flange portions extending horizontally from the upper and lower ends of the power plant frame is formed to be rj+ narrower at an intermediate portion in the longitudinal direction of the vehicle body.

(Function) In the present invention, the following effects can be obtained by the above means.

In other words, by forming one of the flange parts extending horizontally from the upper and lower ends of the power plant frame to be narrow in the middle part in the longitudinal direction of the vehicle body, the torsional force generated due to the transmission of engine driving force to the differential is transferred to the power plant. In addition to being absorbed in the middle part of the frame, the rigidity of the power plant frame end ensured by the wide flange prevents deformation from bending moment caused by wind-up vibration of the differential that occurs while the car is running. It is planned.

(Embodiments) Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

In this embodiment, as shown in FIGS. 1 and 2,
An engine/mission unit I mounted on the front side of an automobile is attached to a front cross member 3 by a conventional method via a pair of engine mounts 2.2 arranged in the vehicle width direction. A control arm 4 is swingably supported by the front cross member 3, and a front wheel 6 is supported by the control arm 4. The front wheel 6 is supported on the vehicle body 7 side via a damper device 5. Further, the front cross member 3 is supported on the vehicle body 7 side by a known method via a suitable elastic member (not shown). The Ennon mission unit l includes an engine as a driving source,
It consists of a clutch and a transmission.

Further, the front five-engine transmission unit 1 is connected via a drive shaft 9 to a differential 8 mounted on the rear side of the automobile. The differential 8 is supported by the rear cross member IO via an elastic member 11.11, and is configured to transmit driving force to the rear wheel 13.13 via an axle shaft 12.12. . The rear cross member 10 is supported by a known method on the vehicle body 7 side via a suitable elastic member (not shown), and is supported by a control arm of the rear wheel 13! 4 is pivotably supported. The rear wheel 13 is supported on the vehicle body 7 side via a damper device 15.

Thus, the engine/mission unit 1 and the differential 8 are firmly connected by the power plant frame 16. The power plant frame 16 is made of a member having a substantially U-shaped cross section with an opening in the horizontal direction and integrally protruding from the upper and lower ends of the vertical side 16a with flanges 16b and 16C extending in the horizontal direction. It has the characteristics of high bending rigidity but flexibility against twisting.

The vertical side 16a of the power plant frame 16 is formed at approximately equal intervals in front of two circular cutouts 17a, 17a formed at the rear end portion on the side of the differential 8. It has a large number of approximately triangular hollow holes 17b, +7b, . . . . Here, the amount of cutout of the circular cutout hole 17a is smaller than the cutout amount of the substantially triangular cutout hole 17b, so that the power plant frame 16
The differential end is made to have higher rigidity than other parts. These hollow holes 17a, +
7a, 17b, 17b--- are formed in order to reduce the weight of the power plant frame 16, and the amount of hollowing out of them is determined by the amount of hollowing out of the power plant frame 16.
The rigidity is determined so as to sufficiently ensure the required rigidity over the entire length. Further, the power plant frame 16
The lower flange portion 16c is narrow at the middle portion and gradually becomes wider in the front-rear direction from the narrow portion SI, while the upper flange portion +6b is narrower at the middle portion SI.
The width is narrower at a position anterior to the narrower portion S1 of 6c,
The width gradually increases from the narrow portion S in the front-rear direction (see FIGS. 3 and 4). With the above configuration, the torsional force that acts on the power plant frame 16 due to the transmission of engine driving force to the differential 8 is effectively absorbed in the [1] narrow portion s1 of the middle portion of the lower flange portion 16c of the power plant frame 16. At the same time, differential 8
The bending moment l-M due to the wind-up vibration is prevented from being deformed by the rigidity of the end portion of the power plant frame 16 in which both the flange portions 16b and 16c are widened by 141 mm. It goes without saying that the upper flange portion 16b may be narrowed at an intermediate portion in the longitudinal direction of the vehicle body.

In the drawings, reference numerals 18 and 19 indicate bolts and nuts for connecting both ends of the power plant frame 16 to the engine/minion unit 1 and the differential 8.

Next, the operation of the power plant frame of the illustrated vehicle will be explained.

By forming the lower flange portion 16c extending horizontally from the lower end of the power plant frame 16 to be narrower than [11] at the intermediate portion in the longitudinal direction of the vehicle body, the differential 8
The torsional force generated due to the transmission of engine driving force to the power plant frame 16 is absorbed by the narrow flange at the intermediate portion of the power plant frame 16, and the bending moment M due to the wind-up vibration of the differential 8 that occurs while the vehicle is running is absorbed. In other words, deformation is prevented by the rigidity of the end portions of the power plant frame 16 ensured by the wide flange portions L6b and 16c.

It goes without saying that the present invention is not limited to the configuration of the above-described embodiments, and that the design can be changed as appropriate without departing from the gist of the invention.

(Effects of the Invention) As described above, according to the present invention, in a power plant frame having a substantially U-shaped cross section that connects a front-mounted engine/minion unit and a rear-mounted differential, One of the flange parts extending horizontally from the upper and lower ends is formed narrowly at the middle part in the longitudinal direction of the vehicle body, so that the torsional force generated due to the transmission of engine driving force to the differential is transferred to the middle part of the power plant frame. The narrow flange absorbs the bending moment caused by wind-up vibration of the differential that occurs while the car is running, and the rigidity of the end of the power plant frame ensured by the wide flange prevents deformation. This has the excellent effect of making it possible to obtain a power plant frame having ideal strength against bending moments and torsional forces.

[Brief explanation of drawings]

FIG. 1 is a plan view of a vehicle having a vehicle power plant frame structure according to an embodiment of the present invention;
The figure is a side view of the main parts of the chassis of an automobile having the power plant frame structure of the vehicle shown in FIG. 1, FIG. 3 is a perspective view showing the power plant frame of the vehicle shown in FIG. 1, and FIG. ), (b), (c) and (d) are enlarged cross sections of (a) - (a), (b) - (b), (c) - (nori and (d) - (d) in Fig. 1) It is a diagram.

Claims (1)

[Claims] 1. Front-mounted engine/mission unit,
In a power plant frame having a substantially U-shaped cross section that connects to a rear-mounted differential, one of the flange portions extending horizontally from the upper and lower ends of the power plant frame is formed to be narrow at an intermediate portion in the longitudinal direction of the vehicle body. A vehicle power plant frame structure characterized by: