JPH0945291A - Automotive bulb - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automotive bulb whose failure at early stages of its life can be made as small as possible, i.e., whose failure due to a nonconducting state at early stages, that may occur although a filament is not dicontinued, can be made as small as possible. SOLUTION: This automotive bulb has a lead-in wire part 13 having both a hook part 13a for hooking the end 15a of a filament 15 sealed to a glass tube 10 and a base 13b sealed to the glass tube 10. The base 13b is made from a dumet material and the hook part 13a from a nickel material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of an automobile light bulb.

[0002]

2. Description of the Related Art Conventionally, in an automobile light bulb, an end 2a of a filament 2 made of tungsten enclosed in a boat-shaped glass tube 1 as shown in FIG. As shown in FIG. 2, the hook portion 3a thus formed is sandwiched, and the base portion 3b of the Dumet wire 3 is sealed and held by the glass tube 1 while the base portion 3b is projected from the end portion of the glass tube 1 to the outside. It is known that the protruding portion is electrically connected to the mouthpiece 4 fitted to the end of the glass tube 1.

[0003]

However, even though this conventional electric bulb for automobiles is a new article, it may not turn on even though the filament 2 is not broken during repeated turning on and off. The failure of such an automobile bulb tends to occur at an early stage of its useful life. This is because the Dumet wire 3 has a copper coating 3d formed by plating on the core material 3c made of an iron-nickel alloy as shown in the sectional view of FIG. 3 to improve the adhesion with the glass tube 1. A borate layer 3e containing boric acid is formed on the outer periphery of the copper coating 3d to light an automobile bulb.
While turning off the light repeatedly, the hook portion 3a of the Dumet wire 3
End portions 2a of the filament 2 are oxidized by the oxidation of the portions sandwiching the end portions 2a of the filament 2 and the growth of this oxide.
The resistance value of the portion sandwiching the filament locally increases, excessive heat is generated in the portion of the hook portion 3a that sandwiches the end portion 2a of the filament 2, and the portion that sandwiches the end portion 2a of the filament 2 opens.
It is considered that this is because the electrical connection between the end 2a of the filament 2 and the dumet wire 3 is broken.

Therefore, the present invention is an automotive light bulb capable of reducing failures at an early stage of its service life as much as possible, in other words, failures caused by non-conduction at an early stage even though the filament is not broken. An object is to provide a light bulb for automobiles that can be reduced.

[0005]

In order to solve the above-mentioned problems, an automobile bulb according to the present invention has a hook portion for hooking an end portion of a filament sealed in a glass tube and a base portion sealed in glass. In an automotive light bulb having a lead wire having a lead wire, the base portion of the lead wire is made of a Dumet material, and the hook portion is made of a nickel material.

According to the present invention, since the nickel material is used for the hook portion of the lead-in wire, it is possible to avoid the occurrence of a gap between the hook portion and the filament as much as possible. Further, the base of the lead-in wire is made of the same Dumet material as the conventional one, and the linear expansion coefficient of the glass and the linear expansion coefficient of the Dumet material are almost the same, and since the borate layer is formed on the base as usual. Even if the automobile bulb expands or contracts within the operating temperature range, it is possible to prevent the sealing performance of the glass tube from being deteriorated.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 3 is an overall view of a part of an automobile light bulb according to the present invention, which is broken away. In FIG. 3, 10 is a boat-shaped (stem) glass tube. Bases 11 and 12 are fitted to both ends of the glass tube 10. The glass tube 10 has a pair of lead wires 13 and 14,
The filament 15 is sealed. Introductory lines 13, 14
Has hook portions 13a and 14a and base portions 13b and 14b. The bases 13b and 14b are made of a Dumet material, which is formed by subjecting nickel steel to a copper plating treatment. The coefficient of linear expansion of this Dumet material is almost the same as the coefficient of linear expansion of the glass tube 10,
The bases 13b and 14b are sealed and held at both ends of the glass tube 10 and project outward from the both ends, and the projections of the bases 13b and 14b are electrically connected to the bases 11 and 12. The hook portions 13a and 14a are made of a nickel material, and the hook portions 13a and 14a are bent in the same manner as in the conventional case shown in FIG. 2, and both ends 15a and 15b of the filament 15 are directly bent to the nickel material at the bent portions. It is sandwiched in contact with.

According to the embodiment of the present invention, both end portions 15a and 15b of the filament 15 are directly contacted with the nickel material, and the hook portions 13a and 14a are well adapted to each other when the filament 15 is contacted. It is possible to prevent the automobile bulb from becoming non-conducting, in other words, becoming non-conducting at an early stage of its useful life, even though the filament is not broken when it is repeatedly turned on and off. That is, when the conventional Dumet wire 3 is used, tungsten comes into contact with the nickel material through the borate layer 3e shown in FIG.
On the basis of the heat generated by the local increase in the resistance value due to the oxidation of the borate layer 3e of a, the sandwiching portion sandwiching the both ends 2a of the filament 2 shown in FIG. Although the electrical connection between the two may be broken, in the present invention, since the tungsten is in direct contact with the nickel material, it is considered that deterioration of the contact state can be suppressed. Further, since the bases 13b and 14b are made of the dumet material as usual, and the borate layer 3e is formed on the bases 13b and 14b as usual, the sealing force of the glass tube within the operating temperature range is improved. It is also possible to prevent the decrease of.

The introduction wires 13 and 14 may be formed by welding hook portions 13a and 14a made of a nickel material to base portions 13b and 14b made of a Dumet wire, or hooks of a slender Dumet wire formed in advance. Part 1
It may be formed by peeling off the borate layer and the copper coating at the portions 3a and 14a.

[0010]

Since the automobile bulb according to the present invention is constructed as described above, the automobile bulb capable of reducing the failure at the early stage of its service life as much as possible, in other words, the filament is not broken. Therefore, it is possible to reduce occurrence of a failure due to non-conduction at an early stage as much as possible.

[Brief description of drawings]

FIG. 1 is an overall view showing a part of a conventional automobile light bulb in a broken manner.

FIG. 2 is a partially enlarged view of a hook portion for explaining a holding state of the end portion of the filament shown in FIG.

FIG. 3 is a sectional view schematically showing the hook portion of FIG. 2 in an enlarged manner.

FIG. 4 is an overall view showing a part of an automobile light bulb according to the present invention by breaking.

[Explanation of symbols]

 10 ... Glass tube 13 ... Introductory wire 15 ... Filament 13a ... Hook part 13b ... Base part 15a ... End part

Claims (1)

[Claims] 1. An automobile bulb having a lead wire having a hook portion for hooking an end portion of a filament sealed in a glass tube and a base portion sealed to glass, wherein the base portion of the lead wire is a Dumet material. And a hook portion formed of a nickel material.