JPS6024335B2 - Method for manufacturing a cast case with anti-vibration structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a cast case with a vibration-proofing structure for use in a transmission case, an engine body, or the like.

In recent years, noise from automobiles has become a major social problem, and the sound radiated from the cast metal case accounts for a fairly large proportion of the automobile noise.

In order to reduce the sound radiated from the cast metal case, there are methods to increase the rigidity of the entire cast metal case by increasing the wall thickness of the case itself and reinforcing it by installing ribs, and to cover the outer periphery of the case with sound absorbing material. has been used. however,
The former is not always satisfactory because it increases the weight, and the latter has problems such as poor maintainability and an increase in the oil temperature inside the case.

In view of the above points, the present invention aims to inexpensively manufacture a cast case with a highly effective anti-vibration structure that avoids increasing the weight of the cast case as much as possible and does not adversely affect maintainability. This method has been devised and will be described below based on the illustrated embodiment.

FIG. 1 shows a damping member 21 made of a thin steel plate formed in substantially the same shape as the inner surface of a transmission case 1 of an automobile as an example of a cast case obtained by the present invention.
, 22 is partially settled, and the settling part 21; a, 221
A and non-adhesive parts 211b and 221b are appropriately distributed and installed. Hereinafter, an example of the manufacturing method of the present invention for producing a cast case having the vibration-proof structure as described above will be explained based on FIG. 2.

First, as shown in FIG. 2, the damping members 21 and 22 are manufactured by press-forming a thin steel plate having a thickness of two ribs or less into approximately the same shape as the inner surface of the case 1. The damping member is divided into two parts for reasons of core manufacturing, but depending on the shape of the casting case, it may of course be manufactured in one piece. Also,
Each end of the damping members 21, 22 is bent inward and provided with locking portions 21a, 21b and 22a, 22b. Next, the damping members 21 and 22 are set in the core forming molds 31 and 32, respectively, as shown in FIG.
and 42 will be produced.

At this time, each of the damping members 21 and 22 has a locking portion 21.
a, 21b and 22a, 22b are formed, so that they get stuck in the core sand and prevent it from easily coming off. In addition, when the above-mentioned locking part is not provided, the damping parts 21 and 22 made of the thin steel plate will be peeled off from the side part by western hot water, which will be described later, and the thin steel plate will ripen from both sides, and a portion of the thin steel plate will melt and eventually melt. This may lead to the destruction of the child.

Next, the core pieces 41, 42 are taken out from the core molds 31, 32, and the upper surfaces of the two core molds 31, 32 are joined together using an epoxy adhesive or the like. As shown in FIG. 2 and 3, a core 40 having damping sections 21 and 22 on its outer periphery is manufactured.

After the core 40 is manufactured in this way, the surfaces of the damping sections 21 and 22 attached to the outer periphery are coated with an anti-fusing agent such as alumina or graphite, such as Suncoat (trade name).
Partially apply an aqueous solution of

That is, welding preventive agents 51 and 62 are applied to areas where welding is not desired. Incidentally, an aqueous solution of shelf sand or the like may be applied as a flux to the part to be settled.

Next, the above-mentioned core 40 is set in the mold 6 as shown in FIG. Areas where no inhibitor is applied or areas where flux is applied are
The surface melts and welds depending on the temperature of the hot water.

On the other hand, the part where the anti-welding agent was applied did not weld, and Case 1
It will be installed in close contact with the inner surface of the The case cast in the above manner is sand-removed in the same way as for ordinary castings, and then machined to form damping members 21 and 2 that are partially welded to the inner circumferential surface as shown in Fig. 1.
A cast case 1 is obtained, in which case 2 is attached.

In such a cast case 1, the amount of radiation blue is significantly reduced due to the frictional damping effect that occurs between the inner surface of the cast case and the non-welded parts of the damping sections 21 and 22 due to the generated noise.

According to experiments conducted by the present inventors, the sound pressure level with respect to the rotational speed of the input shaft in the transmission case manufactured as described above is as shown by line A in Figure 3, and the sound pressure level in the case of the same type without any countermeasures is As is clear from the comparison with the Pressure Bell B line, it was confirmed that the radiated sound was significantly reduced. The present invention has been described above using a case for a transmission as an example in which a damping member is attached to the inner surface of the case. However, the present invention is not limited to only what is shown in the embodiments. It can also be applied to body manufacturing.

Further, the damping member may be attached to the outer surface of the casting case, and in this case, during manufacture, the damping member may be attached to the inner surface of the mold.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a case to which the present invention is applied, FIGS. 2, 1 to 4 are views showing an example of the manufacturing process, and FIG. 3 is a view showing an experimental example of a sound pressure bell. 1: Case, 21, 22: Dumping village, 31, 32
: Core mold, 40: Core, 6: Mold. Ax l figure Fig. 2 (l) Fig. 2 (21 Fig. 2 [31 Fig. 2 [4] Fig. 3)

Claims (1)

[Claims] 1. A damping member made by press-forming a thin steel plate into a shape substantially identical to all or a part of the inner or outer surface of a cast case to be vibration-proof and having a locking part; After applying an anti-welding agent to the surface of the integrally molded core, the core is loaded into a mold and molten metal is poured to partially weld the casting case and the damping member. A method for manufacturing a cast case with an anti-vibration structure. 2. Equipped with the vibration isolation structure as set forth in claim 1, characterized in that the core including the damping member is divided into two or more core pieces, molded, and then joined to form the core. Method of manufacturing a cast metal case.