JPH0353094B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to a method for manufacturing a plastic rod with a rubber bushing, which has a rubber bushing on at least one end, such as stabilizer link rods and buffer rods used in automobile suspensions, etc. be.

[Conventional technology]

Conventionally, among the various rods used in automobile suspensions, the above-mentioned stabilizer link rods and the like have been designed to reduce torsional rigidity and prying rigidity.
It incorporates a rubber bush at the end, through which it is connected to the vehicle body. In other words, the above rod is made by applying preliminary compression to a rubber bush with inner and outer metal cylinders by drawing the outer cylinder or expanding the inner cylinder, and then press-fitting this into the end fitting part (link part) of the metal rod. It is manufactured more than that. However, in this case, complicated operations such as pre-compression of the rubber bushing and assembly into the metal rod are required, and an improvement is desired.

Recently, with the development of plastic materials, plastic rods have been developed to replace metal rods, but the pre-compressed rubber bushes mentioned above are press-fitted into the links of the plastic rods at a high press-fit rate. When press-fitting, the plastic rod will break due to the press-fitting pressure, so
There is no choice but to keep the hot press-in rate low. However, if the press-fitting rate is reduced in this manner, phenomena such as the rubber bushing coming off may occur, so this also poses a problem.

[Problem that the invention seeks to solve]

In this way, when manufacturing a rod with a rubber bushing, whether the rod is made of metal or plastic, it takes time and effort to pre-compress the rubber bushing, and at the same time, the work of assembling the rubber bushing into the rod is complicated. This has become a bottleneck in manufacturing, resulting in problems such as poor manufacturing efficiency and high product costs.

In view of these circumstances, the present invention aims to improve the manufacturing efficiency of rods with rubber bushings.

[Means for solving problems]

In order to achieve the above object, the method for manufacturing a plastic rod with a rubber bushing of the present invention includes a step of preparing a mold having a molding space for forming a plastic rod with a rubber bushing at the end, and an end in the molding space of the mold. arranging a rubber bushing having an inner cylinder in the molding space so that its outer circumferential surface maintains a constant gap with the inner wall surface of the molding space; and injecting a molten molding material into the molding space of the mold. At the end of the space, a recessed part is formed that extends outward around the inner cylinder of the rubber bushing at a portion facing the outer surface of both ends of the rubber bushing. A flange portion is formed that projects outward, and during the injection, the rubber bushing is compressively deformed in the direction of the inner cylinder by the pressure applied to the outer peripheral surface of the rubber bushing, and the outer surface portions of both ends are pushed into the recessed portion. The structure is as follows.

That is, as mentioned above, a rubber bushing having an inner cylinder is placed at the end of the molding space of the molding die,
By injecting the molten molding material into the molding space, at the same time as forming the rod with the molding material, the outer periphery of the link part of the rod is placed around the rubber bushing with the rubber bush compressed using the injection pressure. be able to form. As a result, it is possible to pre-compress and assemble the rubber bush at the same time during the process of forming the plastic rod, without requiring the troublesome effort of forcibly fitting the rubber bush into the link part of the rod as in the past. This will make it possible to improve manufacturing efficiency.

Moreover, at the end of the molding space, a recessed part is formed in a portion facing the outer side surface of both ends of the rubber bushing, and the recessed part is formed to expand outward around the inner cylinder of the rubber bushing, and the above-mentioned recessed part is formed on the outer periphery of the outer side surface of both ends of the rubber bushing. When the outer peripheral surface of the rubber bushing is compressed and deformed in the direction of the inner cylinder due to the high injection pressure during injection molding, the rubber bushing is deformed as shown in Figure 3. extend in its longitudinal direction, and portions of the outer surfaces of both ends of the rubber bushing are pushed into the recessed portions. At this time, even if the molten molding material tries to flow into the recessed portion, the flange portions protruding from the outer periphery of the outer surface at both ends of the rubber bushing prevent the molten molding material from flowing in. Therefore, all the high injection pressure during injection molding is uniformly applied to the outer peripheral surface of the rubber bushing, and the rubber bushing is uniformly compressed in the direction of the inner cylinder.

The rubber bushing having the inner cylinder is not limited in any way, and for example, a rubber bushing vulcanized and bonded to the outer periphery of the inner cylinder metal fitting may be used. The rubber material may be natural rubber, synthetic rubber, or synthetic resin as long as it has rubber elasticity. and,
The vulcanized state of the rubber bushing may be not only fully vulcanized but also semi-vulcanized.

In addition, the above-mentioned molding material is mainly composed of a thermoplastic resin such as nylon resin or a thermosetting resin such as acrylic resin, and glass fiber, carbon fiber, potassium titanate whiskers, etc. are blended with this as a reinforcing material. If necessary, other fillers may be added. Among them, the main component is nylon, the diameter is 0.2 to 1 μm, the length is 5 to
Good results have been obtained using 30 μm potassium titanate whiskers as reinforcement.

However, if the molding material is injected from one end of the molding space to the other, the reinforcing material such as glass fiber will be oriented along the longitudinal direction of the rod, and sufficient reinforcing performance will be exhibited. It is preferable to use a mold that is designed to be suitable for this purpose.

Next, the present invention will be explained in detail based on examples.

〔Example〕

First, a rubber bushing having an inner cylinder is prepared, and a molding mold divided into upper and lower parts having a plastic rod molding space is prepared, and the rubber bushing is placed horizontally at the end of the molding space of the lower mold in the molding mold. Place it in This is shown in FIG. 1 (horizontal sectional view). In the figure, 1 is a lower mold, 2 is a molding space, 2a is an end thereof, and 3 is a rubber bush disposed at the end 2a, which is provided with an inner cylinder 4. 5
2 is a runner serving as a flow path for the molten molding material, 6 is a gate (inlet), and 21 and 22 are voids (recessed portions), which are formed in portions facing outer surfaces 24 and 25 at both ends of the rubber bushing 3. In this case, the end 2a of the molding space 2 has a larger diameter than the outer diameter of the rubber bush 3, and when the rubber bush is arranged, there is melting between the inner peripheral surface of the end 2a and the outer peripheral surface 23 of the rubber bush 3. A void 7 is created for the flow of the molding material.

Next, the upper mold 8 corresponding to the lower mold 1 is attached and the mold is closed. A longitudinal sectional view of this state is shown in FIG. In the figure, 1 is the lower mold, 3 is the rubber bushing,
4 is an inner cylinder thereof, 8 is an upper mold having a molding space 9 corresponding to the molding space 2 of the lower mold 1, and A-
A' indicates the seam between the lower mold 1 and the upper mold 8.
Next, in that state, the molding spaces 2, 9
Then, a melt of a molding material mainly composed of thermoplastic resin is injected from the runner 5 via the gate 6 by injection molding. This injection state is shown in Figures 3 and 4.
As shown in the figure. The above injection molding material is made of a mixture of a thermoplastic resin such as nylon 66 and a reinforcing material such as ^glass fiber.
Injection molding is performed at around 290℃ for 30 to 60 seconds. In this case, the molding material injected under the above-mentioned high injection pressure immediately reaches the end opposite to the gate 6, and from there heads towards the gate 6, sequentially filling the molding spaces 2 and 9. The rod 11 is formed, and the outer peripheral portion 10 of the rubber bush 3 is further formed. In this case, the rubber bushing 3 is compressed inwardly (in the direction of the center axis of the inner cylinder 4) due to the high injection pressure as described above, and at the same time, the portions of the rubber bushing 3 that protrude left and right due to the injection pressure are metallized. The molding material enters the cavities 21 and 22 (see FIG. 1) of the mold, and in that state, the molding material hardens and becomes an outer cylinder part (link part of the rod). The left and right portions of the outer circumferential surface 23 of the rubber bush 3 are formed into flange portions 3a that extend outward beyond the recessed portions 21 and 22, as shown in FIG. , when the entire rubber bushing 3 is compressed inward and the parts protruding to the left and right enter the gaps 21, 22 of the mold, the gaps 21, 2
2 and the side gap 7 (see FIG. 1) are in communication with each other, thereby avoiding the inconvenience that the molten molding material flows into the gaps 21 and 22 and the rubber bush 3 is not compressed sufficiently. There is. As a result, even if the molding material is injected at a high injection pressure as described above, all of the pressure is uniformly applied to the outer circumferential surface 23 of the rubber bush 3, and the rubber bush 3 is uniformly compressed inward, resulting in a good preliminary compression state. You will be able to get it. Usually, the rubber bushing 3 is compressed by 5 to 15% by injecting the resin composition as described above. Next, by opening the two-part mold and taking out the molded product, a rubber bushed plastic rod 13 having rubber bushings 3 at both ends as shown in FIGS. 5 and 6 is obtained.

In the above embodiment, the rubber bushes 3 are provided at both ends of the rod 11, but the rubber bushes may be provided only on one side. In this case, the molding material may be injected from either end of the rod 11. Furthermore, the rubber bushing 3 having the inner cylinder 4 may be vulcanized, as described above, or
A semi-vulcanized material may also be used. In the case of semi-vulcanized materials, they are vulcanized by heating during injection molding, and therefore do not cause any inconvenience. In addition, the injection of molding material is
It may also be done from the center of the rod instead of from the ends.

〔Effect of the invention〕

As described above, the present invention involves the molding of the rod, the assembly of the rubber bush into the rod, and the pre-compression of the rubber bush in order to place a rubber bush having an inner cylinder into a mold and inject a molding material into the mold. The three processes can be performed simultaneously, reducing the number of processing steps, greatly improving manufacturing efficiency, and reducing manufacturing costs.

Furthermore, all the high injection pressure during injection molding is uniformly applied to the outer peripheral surface of the rubber bushing, and the rubber bushing is uniformly compressed in the direction of the inner cylinder, so uneven thickness does not occur in the rubber bushing, and a rubber bushing with good performance can be obtained. Moreover, since the rubber bushing extends in the direction of the inner cylinder and has a longer length, the contact area of the rubber bushing with the inner cylinder becomes larger, increasing the effect of preventing the inner cylinder from coming off, and making it difficult for the inner cylinder and the rubber bushing to get twisted. Furthermore, in the rubber bushing obtained according to the present invention, the flange parts projecting outward from the outer periphery of the outer surface of both ends of the rubber bushing extend toward the link part of the rod at the joint between the outer periphery of the rubber bushing and the link part of the rod. Since the inner cylinder is in the extended state, the effect of preventing the inner cylinder from coming off is even greater, and it is less likely to be twisted.

When the molding material is injected from one end of the molding space of the mold to the other end, reinforcing fibers, etc. in the molding material are oriented along the longitudinal direction of the rod. As a result, the reinforcing effect can be effectively exerted, and a high-strength product can be obtained. Further, according to the present invention, it is possible to use a vulcanized or semi-vulcanized rubber bushing and compress it with a press-fitting molding material, thereby absorbing the shrinkage of the rubber due to vulcanization and forming the rubber bushing. This makes it possible to extremely increase the durability of joining materials.

[Brief explanation of drawings]

Figures 1, 2, 3 and 4 are explanatory views of the manufacture of an embodiment of the present invention, Figure 5 is a side view of a plastic rod with a rubber bushing obtained thereby, and Figure 6. is also a partial cross-sectional view thereof. 1...Lower mold, 2...Molding space, 3...Rubber bushing, 4...Inner cylinder, 5...Runner, 6...Gate, 8...Upper mold, 11...Rod, 13...Plastic with rubber bushing Rod.

Claims (1)

[Claims] 1. A step of preparing a mold having a molding space for forming a plastic rod with a rubber bushing at the end, and a step of preparing a mold having a molding space for forming a plastic rod with a rubber bushing having an inner cylinder at the end in the molding space of the mold, the outer circumferential surface of which is above the The process includes a step of arranging the molding material so as to maintain a constant gap from the inner wall surface of the molding space, and a step of injecting the molten molding material into the molding space of the mold, and at the end of the molding space, a rubber bush is placed on the outer surface of both ends of the mold. A recessed portion extending outward from the inner cylinder of the rubber bushing is formed in the opposing portions, and a flange portion extending outward beyond the recessed portion is formed on the outer periphery of the outer surface of both ends of the rubber bushing,
During the injection, the rubber bush is compressively deformed in the direction of the inner cylinder by the pressure applied to the outer peripheral surface of the rubber bush, and the outer surface portions of both ends of the rubber bush are pushed into the recessed portions. Manufacturing method. 2. The method for producing a plastic rod with a rubber bushing according to claim 1, wherein the injection of the molten molding material is carried out from one end of the rod to the other end in the molding space of the mold. 3. The method for producing a plastic rod with a rubber bushing according to claim 1 or 2, wherein the melt molding material is mainly composed of a thermoplastic resin and contains reinforcing fibers.