JPS607219Y2 - Engine rear mount structure - Google Patents

Description

[Detailed description of the invention] This invention relates to a rear mount structure for a vehicle engine, and in particular to an engine rear mount structure that prevents the transmission of engine vibration from the engine to the floor panel and reduces indoor noise. be.

For example, in a vehicle such as a car, when the engine is mounted facing forward and backward, the engine E is supported (mounted) at two locations M□9M2 on the front and rear sides, as shown in Figure 1. is common.

In the past, various improvements have been made to this type of mount structure in order to reduce engine vibrations transmitted from the engine to the vehicle body, but until now, most of the emphasis has been placed on the mount structure on the front side M1. Place rear side M2
No effective improvements have been made to the structure of

Figure 2 is a cross-section taken at A and A in Figure 1, and shows the rear mount structure of a conventional engine.

As shown in the figure, a reinforcing bracket 2 is welded to the tunnel portion of the floor panel 1.

A mount member 3 is fixed to the brackets 2, 2 via a rubber insulator 4 with bolts 5.

A transmission section 6 on the rear side of the engine is fixedly supported approximately at the center of the mount member 3 via a rear mount insulator 7 with bolts 8 and 9.

Furthermore, Fig. 3 shows a mounting structure used in large passenger cars, etc., in which the left and right side members 10,
10, both ends of the mount member 3a are fixed via rubber insulators 4, and a transmission section 6 is fixedly supported via an insulator 7 to substantially the middle of the mount member 3a.

According to the rear mount structure configured as described above, in any mount structure, relatively high frequency engine vibrations are absorbed by the insulator 7 and rubber insulator 4.
This action prevents the transmission of energy from the engine transmission section 6 to the mount member 3.3a and further to the floor panel 1.

However, when this rear mount structure is viewed as one vibration system that includes the floor panel, engine vibration at a relatively low frequency that causes the floor panel to resonate resonates.
There is a problem that this vibration transmission cannot be effectively prevented.

That is, according to such conventional engine rear mount structures, in all conventional examples, the transmission section 6 of the engine is fixed to substantially the middle of the mount members 3, 3a, so that the left and right vibrations are transmitted evenly. It has become.

Therefore, when the transmission part 6 of the engine vibrates in the direction of the black arrow as shown in FIG. The panel as a whole vibrates in a symmetrical mode, as shown in the schematic diagram of FIG.

Furthermore, Japanese Utility Model Publication No. 51-5856 shows a diagram in which the length from the floor panel support part of the mount member to the mounting part of the transmission part is different on the left and right sides, but there is no explanation as to the reason for this. Furthermore, since the difference in length is extremely small, it is thought that in this case as well, the entire floor panel vibrates in a symmetrical or similar mode.

Vibration in this mode causes a large change in the volume of the vehicle interior, which is a major cause of muffled noise at low speeds, and is a major problem in measures to reduce vehicle interior noise.

This idea was created in view of these conventional problems, and in the engine rear mount structure, the length from the floor panel support part of the mount member to the mounting part of the transmission part is set to a different value on the left and right sides, and The above problem is solved by providing a transmission characteristic changing means that makes the engine vibration transmission characteristics to the floor panel support part of the mount member different on the left and right sides, and making the engine vibration transmission characteristics to the floor panel support part opposite in phase on the left and right sides. The aim is to obtain a rear mount structure for the engine.

Hereinafter, the present invention will be explained based on the drawings.

FIG. 5 shows an embodiment of the structure of the present invention in which the length from the floor panel support part of the mount member to the mounting part of the transmission part is set to different values on the left and right sides.

In the figure, reference numeral 1 denotes a floor panel of a traveling vehicle, and a reinforcing bracket 12 is welded to a part of the tunnel portion of the floor panel 1.

Furthermore, side members 10.10 are welded to the floor panel 1.

The reinforcing bracket 12 and one side member 10 are provided with rubber insulators 4, which are elastic members, at the support portions at both ends.
, 4 is mounted horizontally and fixed with bolts 15 and 15.

This mount member 13 is one side member 10
It has an asymmetrical shape, with the sides becoming slightly wider at the end.

Further, on the slightly right side of the central part of the mount member 13 in the drawing, the transmission part 6 of the engine is fixedly supported via a mount insulator 17. The left and right sides have different lengths of 1° and 11.

Next, FIGS. 7 and 8 show an embodiment of a transmission characteristic changing means, which differs the engine vibration transmission characteristics of the mount member to the floor panel support portion on the left and right sides, among the configurations of the present invention.

In FIG. 7, a concentrated mass (mass damper) 11 is provided at one end of the mount member 13a, and in FIG. 8, the rigidity of the rubber insulator 14 is made different on the left and right sides.

As a result, left and right mount members 13a and 13b having different vibration transmission characteristics to the floor panel are formed.

According to the engine rear mount structure having such a configuration, the transmission part 6 is shifted slightly to the right of the center of the mount member 13, and the length from the floor panel support part of the mount member 13 to the mounting part of the transmission part 6 is equal to the left and right. 1° and 1□, and there is a concentrated mass 1 at one end of the mount member.
1 or by making the stiffness of the insulators elastically different on the left and right sides of the mount member so that the vibration transmission characteristics to the floor panel 1 are in opposite phases on the left and right sides, as shown in Fig. 6a. When the transmission section 6 is displaced in the direction of the black arrow due to engine vibration, the mount member 13 is displaced in the direction of the white arrow.

Due to this displacement, the vibration displacements of the left and right sides of the floor panel 1 become opposite in phase as shown in Figure 6, and the vibration displacements cancel each other out and the change in the passenger compartment volume is reduced, which causes muffled noise at low speeds. Noise caused by vibration of the floor panel can be prevented.

As explained above, according to the present invention, in the engine rear mount structure, the engine vibration transmission characteristics to the floor panel are set in opposite phases on the left and right sides, making it possible to prevent muffled noise at low speeds and reduce cabin noise. Great effects can be obtained in terms of reduction measures.

[Brief explanation of the drawing]

Fig. 1 is a schematic side view showing the support state of a general engine, Figs. 2 and 3 are views showing different conventional structures, and are sectional views corresponding to lines A and A in Fig. 1, and Fig. 4. a ”-'
Fig. 5 is a cross-sectional view of one embodiment of the mount member used in this invention, and Fig. 6 a and b are schematic diagrams to explain the operation of this invention. 7 and 8 are cross-sectional views of an embodiment of the engine vibration transmission characteristic changing means used in this invention. 1... Floor panel, 4... Insulator, 6... Transmission section, 10...
...Side member, 11...Mass damper, 12...Reinforcement flaket, 13.13a, 1
3b...Mount member 14...Insulator, 15...Bolt.

Claims (3)

[Scope of utility model registration request] (1) In an engine rear mount structure in which both ends of a mount member are elastically supported under a tunnel of a floor panel in which a transmission part of an engine mounted on a running vehicle is arranged, and the transmission part is mounted on this mount member. , the length from the force of the floor panel support part of the mount member to the mounting part of the transmission part is set to a different value on the left and right sides, and the engine vibration transmission characteristics of the mount member to the floor panel support part are set to be different on the left and right sides. A rear mount structure for an engine, characterized in that a characteristic changing means is provided so that engine vibration transmission characteristics to the floor panel support portion are made to have opposite phases on the left and right sides. (2) Utility model registration claim 1, characterized in that, as the transmission characteristic changing means, elastic members having different spring constants on the left and right sides are used to elastically support both ends of the mount member.
Rear mount structure of the engine described in section. (3) The rear mount structure for an engine according to claim 1, wherein a mass damper is provided at at least one end of the mount member as a transmission characteristic changing means.