JP3642350B2 - Vibration isolator - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a vibration isolator for an automobile, and more particularly to a structure of a vibration isolator used as a rear mount that elastically supports a rear portion of an engine.
[0002]
[Prior art]
In order to provide vibration isolation support for the engine and the transmission connected to the rear end of the FR type automobile, a rear mount for elastically supporting the transmission from below is provided in addition to a pair of mounts for supporting both sides of the engine. (For example, Japanese Utility Model Laid-Open No. 4-80941, Japanese Utility Model Laid-Open No. 61-61226, Japanese Utility Model Laid-Open No. 63-168340, etc.).
[0003]
A typical structure of this rear mount is shown in FIG. In the figure, reference numeral 1 denotes an upper mounting bracket whose central part is bolted to a transmission (not shown), and a lower mounting bracket 2 whose central part is fixed to a rear sub-frame F of the vehicle by a bolt 4 faces below. It is arranged. The upper mounting bracket 1 and the lower mounting bracket 2 have both ends in the vehicle left-right direction bent obliquely upward, and elastic bodies 31 and 32 are interposed and fixed between opposing surfaces of the left and right ends. Further, the lower mounting bracket 2 is provided with a convex portion 23 in the center portion thereof, penetrating a rod-shaped body extending from the upper mounting bracket 1 into a through hole on the upper surface thereof, and the upper mounting bracket 1 having a large diameter at the tip of the rod-shaped body. The stopper 7 restricts the amount of movement in the vertical direction.
[0004]
[Problems to be solved by the invention]
By the way, the rear sub-frame F is conventionally made of an iron plate. However, the rear sub-frame F is heavier, obstructs the weight reduction of the vehicle body, has a low resonance point, and causes noise. It has been studied to form a casting.
[0005]
However, the aluminum casting is inferior to the iron plate in strength and toughness, and it is difficult in terms of durability to replace the rear subframe F with the aluminum casting in the conventional structure. That is, in the schematic diagram of FIG. 4, when a large load is input and the transmission T moves greatly upward, the force passes through the upper mounting bracket 1, the stopper 7, the convex portion 23, the lower mounting bracket 2, and the bolt 4. The data is input to the frame F (B in the figure indicates the vehicle body). That is, since a high stress is applied to the connecting portion (bolt fastening portion) with the lower mounting bracket 2 that is weaker than other portions, the rear sub-frame F may be destroyed by a large load input during a collision or the like. It was. Therefore, the conventional aluminum casting sub-frame does not have the stopper 7 and cannot be controlled when the transmission moves upward.
[0006]
Accordingly, an object of the present invention is to realize a rear mount structure for an engine that has sufficient strength and impact resistance and can be reduced in weight by replacing the rear subframe with aluminum and can prevent noise.
[0007]
[Means for Solving the Problems]
The vibration isolator of the present invention (FIG. 1) supports a transmission integrally provided at the rear end of the engine from below, and includes an upper mounting bracket 1 attached to the transmission and a lower mounting bracket 21 attached to the vehicle frame F. , 22 are arranged opposite to each other, and elastic bodies 31, 32 are interposed between the upper mounting bracket 1 and the lower mounting brackets 21, 22. Specifically, the vehicle frame F is made of an aluminum alloy, and the upper mounting bracket 1 is attached to the transmission at the center in the vehicle left-right direction. The left and right end portions 12, 13 of the upper mounting bracket 1 are bent obliquely upward in an inverted C shape so that the upper half surfaces 211, 221 of the pair of left and right lower mounting brackets 21, 22 having a substantially U-shaped cross section are opposed to each other. The pair of elastic bodies 31 and 32 are interposed between the opposing surfaces so as to be inclined in the inward direction. The lower half surfaces of the pair of left and right lower mounting brackets 21 and 22 are fixed to a mounting portion F1 protruding from the left and right end side surfaces of the vehicle frame F.
[0008]
In addition, the upper mounting bracket 1 has stopper surfaces 51 and 52 that extend sideways at the center in the left-right direction of the vehicle and surround the vehicle frame F and face the upper and lower surfaces and the side surfaces thereof at a predetermined interval. And a stopper portion 5 that restricts the amount of movement of the upper mounting bracket 1 is formed. An elastic material 6 is interposed between the stopper portion 5 and the vehicle frame F. As a result, a vibration isolator having a stopper function and a vibration isolating function arranged in parallel is provided.
[0009]
[Action]
An input transmission path of the vibration isolator of the present invention is schematically shown in FIG. In the figure, when the transmission T moves upward, the force is directly input to the vehicle frame F from the upper mounting bracket 1 via the stopper portion 5. In the figure, B is a vehicle body. In the configuration of the present invention, the lower mounting bracket 2 is mounted on the vehicle frame F at a position where the lower mounting bracket 2 does not come into contact with the stopper portion 5, and the input is not passed through the lower mounting bracket 2 and the bolt 4. Concentration is smaller than before. In this way, the stopper function and the vibration isolating function are arranged in parallel, and the respective required values are realized separately, so that the strength as a device is greatly improved, and even if the vehicle frame F is made of an aluminum alloy, a large load There is little risk of destruction due to the input of. Moreover, weight reduction is possible by making the vehicle frame F into an aluminum alloy, and noise can be prevented by shifting the resonance point to the high frequency side.
[0010]
【Example】
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1A and 1B, an engine rear mount is positioned below a transmission (not shown) connected to the rear end of the engine, and an upper mounting bracket 1 attached to the transmission and a rear frame as a vehicle frame. A pair of left and right lower mounting brackets 21 and 22 attached to the subframe F are provided, and a pair of left and right rubber elastic bodies 31 and 32 are interposed and fixed therebetween. The transmission is usually disposed in a tunnel-like portion that is provided on the floor panel of the automobile and extends in the vehicle front-rear direction, and the rear subframe F is arranged so as to span the lower end opening of the tunnel portion. It is adapted to be fixed to the floor panel at both ends. In FIG. 1A, the left-right direction of the drawing is the left-right direction of the vehicle, and the direction indicated by the arrow in the figure is the front of the vehicle.
[0011]
The upper mounting bracket 1 has a flat plate shape, and has a bolt hole 11 for fixing the transmission at the center in the left-right direction of the vehicle, and the left and right end portions 12 and 13 are bent in an obliquely upward shape in an inverted C shape. The lower mounting brackets 21 and 22 are substantially U-shaped in cross section, and upper half surfaces 211 and 221 are respectively opposed to the left and right end portions 12 and 13 of the upper mounting bracket 1, and the lower half surfaces are the left and right sides of the rear subframe F. It is fixed with bolts 4 on mounting portions F1 that project from the side surfaces of the front portion of the vehicle. Then, the block-like elastic bodies 31 and 32 are joined to each other between the opposing surfaces of the upper mounting bracket 1 and the lower mounting brackets 21 and 22 by inclining in the inward direction.
[0012]
The upper mounting bracket 1 serves as a stopper portion 5 that extends downward from the vehicle rear side edge at the center in the left-right direction and extends to surround the upper and lower surfaces and the rear side surface of the rear subframe F. The stopper portion 5 has a stopper surface 51 that opposes the upper and lower surfaces of the rear subframe F at a predetermined interval, and a stopper surface 52 that opposes the rear side surface of the rear subframe F at a predetermined interval. In addition, the relative displacement of the upper mounting bracket 1 in the vertical direction and the front-rear direction with respect to the rear sub-frame F is restricted. Further, the rear sub-frame F is coated with an elastic material 6 on the outer periphery of the central portion facing the stopper surfaces 51 and 52 so that no abnormal noise is generated when contacting the stopper portion 5. The stopper portion 5 is provided with reinforcing ribs 53 along both left and right edges.
[0013]
The rear subframe F is preferably made of an aluminum alloy in terms of reducing the weight of the apparatus. Considering the impact resistance, a forged product is preferable to an aluminum casting (JIS AC4C or the like), and it is particularly preferable to use a 6000 series aluminum forged product such as AA6061, which is excellent in strength, elongation and rust prevention.
[0014]
With the above configuration, when the transmission moves up and down largely, the force is directly input to the rear subframe F from the upper mounting bracket 1 via the stopper portion 5. In the present invention, this stopper function and an anti-vibration function comprising the upper mounting bracket 1, the elastic bodies 31, 32, and the lower mounting brackets 21, 22 are arranged in parallel, and the lower mounting brackets 21, 22 are connected to the stopper portion 5 described above. Since it is fixed to the rear sub-frame F at a position away from the center, the stress concentration applied to the rear sub-frame F is smaller than that of a conventional device in which these functions are arranged in series.
[0015]
For this reason, the strength required for each member is rather lowered, and the thickness of the upper mounting bracket is reduced from 4.5 mm to 3.2 mm, and the thickness of the lower mounting bracket is decreased from 4.5 mm to 2.0 mm. It has become possible to reduce the number of bolts for fixing the metal fittings from four to two. Moreover, the strength of the apparatus is greatly improved. In the conventional apparatus shown in FIG. 3, the rear sub-frame F made of aluminum material was cracked due to partial stress at a load of 810 (N). The apparatus did not deform until 1600 (N). Further, the eigenvalue of the device is further increased (708 Hz → 850 Hz) as compared with the conventional device using an aluminum material, and noise generation due to resonance can be prevented more reliably.
[0016]
In the above embodiment, the elastic material 6 is covered on the outer periphery of the central portion of the rear subframe F facing the stopper portion 5, but the elastic material 6 is covered with the stopper surfaces 51 and 52 of the stopper portion 5. It may be provided. Alternatively, the stopper 5 may be further extended and bent upward to provide a stopper surface facing the front side surface of the rear subframe F.
[0017]
【The invention's effect】
According to the present invention, the strength and impact resistance of the apparatus are greatly improved, so that there is little risk of breakage during a collision or the like even if the rear subframe is made of an aluminum material. In addition, the weight of the apparatus can be reduced, and noise due to resonance can be prevented. Therefore, the apparatus can be suitably used as a rear mount of the engine and exhibits an excellent effect.
[Brief description of the drawings]
FIG. 1A is an overall perspective view of a vibration isolator of the present invention, and FIG. 1B is a partial perspective view of the device of FIG.
2A is a view showing an input transmission path of the vibration isolator of the present invention, and FIG. 2B is a cross-sectional view taken along the line IIB-IIB in FIG.
FIG. 3 is a perspective view of a conventional vibration isolator.
FIG. 4 is a diagram showing an input transmission path of a conventional vibration isolator.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Upper mounting bracket 11 Bolt hole 12, 13 Left and right both ends 2 Lower mounting bracket 21, 22 Lower mounting bracket 31, 32 Rubber elastic body 4 Bolt 5 Stopper portion 51, 52 Stopper surface 6 Elastic material 7 Stopper

Claims (1)

A transmission that is integrally provided at the rear end of the engine is supported from below, and an upper mounting bracket that is attached to the transmission and a lower mounting bracket that is mounted to the vehicle frame are arranged to face each other. An anti-vibration device having an elastic body interposed therebetween, wherein the vehicle frame is made of an aluminum alloy, the center portion of the upper mounting bracket in the vehicle left-right direction is mounted on the transmission, and the left and right of the upper mounting bracket are Both ends are bent diagonally upward in an inverted C shape, facing the upper half surface of the pair of left and right lower mounting brackets with a substantially U-shaped cross section, and a pair of elastic bodies tilted inwardly between the opposing surfaces The lower half of the pair of left and right lower mounting brackets is fixed to the mounting part that projects from the left and right end sides of the vehicle frame. And the side edges of the vehicle lateral direction middle portion of the upper mounting brackets tighten not extend downward, the upper mounting has a stopper surface facing at a respective predetermined interval and the upper and lower surfaces and side surrounding the vehicle frame A vibration isolator having a stopper function and an anti-vibration function arranged in parallel by forming a stopper part that regulates the amount of movement of the metal fitting, and interposing an elastic material between the stopper part and the vehicle frame. .

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