JPH0331864Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an engine mount that supports an automobile engine.

<Conventional technology> As a conventional engine mount of this type,
The technique described in JP 60-65446 and the like can be mentioned.

The engine mounts shown in the above technologies each consist of a main body made of an elastic material for elastically supporting and absorbing automobile engine vibrations, and a metal bracket for securing to the engine and the vehicle body. There is.

<Problems to be solved by the invention> In recent years, in order to reduce the weight of vehicles in line with improvements in fuel efficiency, there has been a demand for each component that constitutes a vehicle to be lighter and smaller. However, engine mounts are required not only to isolate engine vibrations, but also to support the weight of the engine and suppress engine movement caused by external forces. For this reason, it is desirable to reduce the thickness of the metal bracket, which accounts for most of the weight of the entire engine mount, in order to meet the demand for weight reduction. However, reducing the thickness of the metal bracket reduces its strength and durability. There was a problem with the decline.

Therefore, an object of the present invention is to provide an engine mount in which the thickness of the bracket portion can be reduced (lightened) without compromising strength, durability, etc.

<Means for solving the problem> The engine mount according to the present invention has an elastic body interposed between the outer cylinder and the inner cylinder, and the outer frame cylinder made of a thin metal plate and the support plate made of a thin metal plate are integrated. In an engine mount, the outer cylinder is press-fitted into an outer frame cylinder of a bracket formed in the cylinder, and the engine is elastically supported on the body of an automobile by the bracket and the inner cylinder, and the bracket is formed of a thin metal plate. At least the portion of the outer frame cylinder that is particularly subjected to stress concentration is subjected to nitriding treatment or soft nitriding treatment.

<Function> Although the metal bracket of the engine mount of the present invention uses a thinner steel plate than conventional ones to reduce weight, at least the part of the bracket that receives stress concentration is nitrided or softened. It is nitrided, and due to the high hardness of the nitrided layer formed on the surface and the high fatigue resistance due to compressive residual stress, it is possible to obtain high strength and durability equivalent to or higher than conventional products.

In addition, the outer frame cylinder of the bracket is expanded in diameter by the engine mount installed inside and is subjected to strong tensile stress, but this is alleviated by compressive residual stress due to the nitriding or soft nitriding treatment applied to the surface, resulting in high durability. You can get sex.

<Example> The present invention will be specifically described below based on the attached drawings.

FIG. 1 shows an embodiment of an engine mount according to the present invention, and FIG. 2 shows a bracket portion of the engine mount shown in FIG.

In the figure, the main body part 1 is vulcanized and bonded to an inner cylinder 2 made of metal and an outer cylinder 3 made of metal as well, and after applying adhesive to the outer surface of the inner cylinder 2 and the inner surface of the outer cylinder 3,
It is mounted in a mold (not shown) and integrally molded by injecting and vulcanizing an elastic material such as rubber into the mold. After that, a drawing process is performed to reduce the outer diameter of the outer cylinder 3. This drawing process is performed for the purpose of improving the durability of the main body part 1 by reducing the outer shape and applying compressive residual stress to the main body part 1.

On the other hand, the bracket 4 is an outer frame cylinder 4 made of a thin metal plate.
a, a support plate 4b made of a thin metal plate with a substantially L-shaped cross section, and a mounting bolt 4c driven into a hole in the support plate 4b, and the end of the support plate 4b is connected to the outer frame cylinder 4.
It is welded to the outer periphery of a. This bracket 4
Metals are heat-treated to improve their strength and durability, but in this example, soft nitriding was performed in a molten salt bath for about 90 minutes in an atmosphere of about 570°C. 10 microns, hardness Hv500~
In the bracket 4 above, a nitrided layer of 600 was obtained.
The main body 1, inner tube 2, and outer tube 3 are press-fitted together, and then the surface is coated for rust prevention.

The engine mount according to the embodiment of the present invention is fixed to the engine by the mounting bolt, and is also fixed to the vehicle body by a bolt (not shown) that passes through the inner cylinder 2 and the mounting portion on the vehicle body (not shown).

In the above-mentioned mounted condition, if the vehicle body and engine move relatively significantly due to vehicle body rocking, large stress will be generated near section A in the figure due to stress concentration, but with the engine mount of the present invention, teeth,
As mentioned above, soft nitriding treatment is applied, and a highly hard nitrided layer is formed on the surface of the bracket, and high compressive residual stress is generated inside the metal due to the nitriding treatment, which prevents cracks from occurring. It not only effectively suppresses cracking, but also has sufficiently high strength and durability to effectively suppress the progression of cracking even if cracking occurs, and does not impair the durability of the bracket. There is no damage to the durability of the stress concentrated portion.

Conventionally, a steel plate with a thickness of 6 mm was used for this bracket 4, but the one subjected to soft nitriding treatment in this example has durability equal to or higher than that of the conventional one even if the thickness is reduced to 4.5 mm. The present inventor has confirmed that this soft-nitriding treatment can provide about three times the durability. This also made it possible not only to reduce the plate thickness, but also to reduce weight by downsizing the entire engine mount.

Furthermore, in this invention, the nitrocarburizing treatment applied to the bracket forms a compound layer with non-metallic properties on the metal surface, and this compound layer is chemically stable and resistant to water and ozone. Since it has remarkable resistance to corrosion, it can also prevent deterioration in strength and durability due to corrosion.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and can be embodied as shown below, for example.

(1) The bracket is not assembled by welding, but may be assembled by other methods.

(2) The metal fitting treatment may be nitriding treatment. In the nitriding process, a nitrided layer with high hardness is similarly formed on the surface of the bracket, and high compressive residual stress is generated inside the metal.

(3) The metal fitting treatment may be applied to the entire metal fitting. In this case, strong tensile stress acts on the outer frame cylinder of the bracket due to its diameter being expanded by the engine mount installed inside, and in addition, the area near section A in the figure is affected by the vibration of the car body. When the engine moves relatively large or due to engine vibration, large stress is generated due to stress concentration, but the high hardness of the nitride layer formed on the surface not only effectively suppresses the occurrence of cracks. Even if cracks occur, the tensile stress is effectively alleviated by the internal compressive residual stress caused by the nitrided layer, and the progress of cracks becomes extremely slow, resulting in high durability.

<Effects of the invention> As described above, the engine mount of the invention has the following effects:
At least the outer frame cylinder of the bracket formed of a thin metal plate is subjected to nitriding or soft nitriding, and the nitriding or soft nitriding process reduces weight and reduces the weight without impairing strength, durability, etc. Miniaturization can be achieved.

[Brief explanation of the drawing]

1 and 2 show an embodiment embodying the present invention, with FIG. 1 showing the entire structure and FIG. 2 showing only the bracket. In the figure, 1: main body, 2: inner cylinder, 3: outer cylinder, 4: bracket, 4a: outer frame cylinder, 4b: support plate, 4c: mounting bolt, A: stress concentration part.

Claims (1)

[Scope of utility model registration request] An elastic body is interposed between the outer cylinder and the inner cylinder, and the outer cylinder is press-fitted and fixed into the outer cylinder of a bracket in which an outer cylinder made of a thin metal plate and a support plate made of a thin metal plate are integrally formed. In an engine mount that elastically supports an engine on a vehicle body by the bracket and the inner cylinder, at least the outer frame cylinder of the bracket formed of a thin metal plate is subjected to nitriding treatment or soft nitriding treatment. An engine mount featuring