JPH0478096B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a vehicular lamp, and more particularly to a method for forming the vehicular lamp by blow molding.

〓Prior art〓 Conventionally, when this type of vehicle lamp is formed by blow molding, the shape of the vehicle lamp is usually formed by blow molding other products, such as containers such as bottles. For this reason, the unevenness of the wall thickness was severe, and it was considered that it was impossible to obtain a product that could be put to practical use.

〓Problems to be solved by the invention〓 However, the above-mentioned blow molding has excellent productivity, as a hollow product can be obtained in a single molding process, and it has not been possible to form this type of lamp using blow molding. Although this method is expected to have a significant effect on cost reduction, such a method has not been provided.

〓Means for Solving the Problems〓 The present invention provides a method for forming a vehicle lamp by blow molding as a specific means for solving the problem that conventional molding is impossible. In the method, the blow molding mold for the vehicle lamp is provided with a cutting blade at least at a position corresponding to approximately the vicinity of the optical axis center line of the vehicle lamp, and the cutting blade is provided on the lens surface side along the optical axis center line. A method for forming a vehicular lamp, characterized in that the length is held by the cutting blade so that the length of the housing is the same as the length of the housing, or the length of the length of the lens side is slightly longer. By providing this, the problem is solved by making it possible to form a vehicle lamp with a uniform wall thickness.

Embodiment Next, the present invention will be described in detail based on an embodiment shown in the drawings.

First, to explain the basic process of forming a vehicle lamp by blow molding according to the present invention, reference numeral 1 is shown in FIG.
1 is a nozzle of a blow molding machine, and from this nozzle 1 a softened tube-shaped resin called parison 2 is extruded, forming a lens side mold 3a with an outer diameter and a housing. The parison 2 is covered with a surface-side mold 3b, and while the parison 2 is in a softened state, compressed air A is blown into the inside to form the parison 2 in close contact with the inner surfaces of the molds 3a and 3b. Since the end portion 2a of the parison 2 is open, the respective molds 3a and 3b are provided with cutting blades 3c and 3d corresponding to this portion. The portion 2a is pressed into close contact and closed. In the present invention, this cutting blade not only has the function of closing the opening, but also has the function of holding and fixing the parison 2. The mating surface 4 of the mold 3a and the mating surface 5 of the mold 3b on the housing surface side are formed into corresponding curved lines, and the mating surfaces 4 and 5 serve as cutting edges.

The one shown in FIG. 2 is the lens surface side mold 3a.
This figure shows a vehicle lamp 6 molded with a housing side mold 3b, and the side surface of this lamp 6 has a mesh line 6a formed by the mating surfaces 4 and 5 of the molds 3a and 3b.
will appear. Optical axis center line Z of this lamp 6
FIG. 3 shows a cross section taken along the lens surface, and the total surface distance R on the lens surface side to the mesh line 6a of each of the upper and lower surfaces is shown in FIG.
The mating surfaces 4 and 5 of the molds 3a and 3b are set so that the distance H on the housing surface side is in the relationship R≈H in the range of R=H or R>H. By making the surface distances R and H substantially the same in this way, it is possible to make the wall thickness substantially the same and uniform.

Furthermore, in practice, it is possible to provide cutting edges on all of the mating surfaces 4 and 5 of the lens surface side mold 3a and the housing surface side mold 3b, but this type of blow molding requires cutting edges at each part depending on the shape etc. Since the elongation conditions are often different and it is difficult to predict in advance, the part of the mating surfaces 4 and 5 where the cutting edge is to be provided is determined according to the actual situation after trial driving. However, in order to obtain the above effect, it is necessary to provide it at least near the optical axis center line Z.

In addition, what is indicated by the reference numeral 7 in the figure is a light bulb including a socket part that is attached to this vehicle lamp 6.
Since this part serves as an opening, it is possible to freely make changes such as providing an inlet for compressed air A during blow molding in this part.

<Effects of the Invention> As explained above, the method for forming a vehicle lamp according to the present invention includes a blow-molding mold provided with a cutting edge at least at a position corresponding to approximately the center line of the optical axis of the vehicle lamp. and held by the cutting blade so that the surface distance on the lens surface side and the surface distance on the housing surface side along the optical axis center line are the same, or the surface distance on the lens surface side is slightly longer. This makes it possible to manufacture this type of lamp using the blow molding method by obtaining a uniform wall thickness, which eliminates the trouble of gluing the lens surface and housing surface, for example, and reduces the process. This has an outstanding effect on simplification and cost reduction.

[Brief explanation of drawings]

FIG. 1 is an explanatory view showing an example of the method for forming a vehicle lamp according to the present invention, FIG. 2 is a plan view showing a lamp obtained by the method for forming a vehicle lamp according to the present invention, and FIG. 3 is a sectional view taken along the optical axis center line Z in FIG. 2. FIG. 1...Nozzle, 2...Parison, 3a...Lens surface side mold, 3b...Housing surface side mold, 4,
5... mating surface, 6... vehicle lamp, 6a... engagement line.

Claims (1)

[Claims] 1. In a method for forming a vehicle lamp by a blow molding method, the blow molding mold for the vehicle lamp has a cutting edge at least at a position corresponding to approximately the vicinity of the optical axis center line of the vehicle lamp. The cutting blade is provided so that the surface distance on the lens surface side and the surface distance on the housing surface side along the optical axis center line are the same, or the surface distance on the lens surface side is slightly longer. A method for forming a vehicle lamp, the method comprising holding and forming a vehicle lamp.