JPH04342922A - Manufacture of electrode for discharge lamp - Google Patents

Abstract

PURPOSE:To prevent the drop or displacement of a coil by rigidly attaching an electrode coil to an arbor without giving damages on top of the arbor. CONSTITUTION:Both on a coil winding beginning part and on a coil winding end part of a coil 1 of which inside diameter is smaller than the outside diameter of an arbor 2 in a free state, protruded parts 1a and 1b are provided integrally with a coil such that it projects from the outside diameter part of the coil outward in the radial direction. A moment is added on the protruded parts 1a and 1b in such a way that the inside diameter of the coil becomes larger, thereby the inside diameter of the coil is enlarged to be larger than the outside diameter of the arbor 2, followed by inserting the arbor 2 into the inside diameter part of the coil 1, and subsequently the moment is removed so that the coil 1 is rigidly attached to the tip part of the arbor 2.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing electrodes used in high-intensity discharge lamps such as metal halide lamps.

0002

2. Description of the Related Art Generally, high-intensity discharge lamps such as metal halide lamps use electrodes in which a coil made of tungsten wire or the like is coupled to the tip of a core rod made of tungsten wire or the like. In an electrode with such a configuration, in order to prevent cracks or chips from occurring at the tip of the core rod when the core rod is inserted into the inner diameter of the coil and assembled, conventionally, as shown in FIG. The inner diameter of the coil is the core rod 10.
The electrode was formed by inserting a core rod 102 into a coil 101 whose outer diameter was slightly smaller than that of the coil 101. For example, using a tungsten wire with a wire diameter of 0.4 mm, the inner diameter of the coil is 0.4 mm.
A coil with a diameter of 585 mm was created, and a core rod with an outer diameter of 0.6±0.006 mm was inserted into this coil to form an electrode.

0003

[Problems to be Solved by the Invention] In the conventional electrode manufacturing method, the inner diameter of the coil must be selected to be slightly smaller than the outer diameter of the core rod in order to prevent the tip shape of the core rod from collapsing due to damage. Can not. Therefore, due to variations in dimensions, the coil may fall from the core rod during the lamp life, resulting in a malfunction, or when the product is transported by vehicle or ship, the coil position may become loose due to vibration. There have been problems in that the coils may deviate, making it impossible to obtain desired lamp characteristics, or the coils may fall.

The present invention was made to solve the above-mentioned problems in the conventional method of manufacturing electrodes for discharge lamps.
It is an object of the present invention to provide a method for manufacturing an electrode for a discharge lamp, in which an electrode coil and a core rod are firmly connected to each other, thereby preventing the coil from falling or shifting.

[0005]

[Means and Effects for Solving the Problems] In order to solve the above problems, the present invention provides a method for manufacturing an electrode for a discharge lamp in which a coil is coupled to the tip of a core rod. A protrusion is provided at both the coil winding start part and the coil winding end part of the coil, which is smaller than the outer diameter of the rod, so as to protrude radially outward from the coil outer diameter part integrally with the coil wire, and the protrusion part After applying a moment to increase the inner diameter of the coil to make the inner diameter of the coil larger than the outer diameter of the core rod, the core rod is inserted into the inner diameter of the coil and the two are connected.

In the above manufacturing method, a moment is applied to the protrusions at both ends of the coil to make the inner diameter of the coil larger than the outer diameter of the core rod, and then the core rod is inserted into the inner diameter of the coil. It can be easily inserted into the inner diameter of the coil without damaging the tip, and by removing the moment that was applied after inserting the core rod into the inner diameter of the coil, the coil is firmly held in the specified position on the core rod. can be combined with Therefore, it is possible to easily manufacture an electrode for a discharge lamp that can effectively prevent the coil from falling or shifting without causing damage to the tip of the core rod.

[0007]

[Example] Next, an example will be explained. FIG. 1 is a process diagram for assembling an electrode for a discharge lamp to explain an embodiment of the method for manufacturing the electrode for a discharge lamp according to the present invention. In the figure,
1 is a double-wound coil having an inner diameter sufficiently smaller than the outer diameter of the core rod in a free state, and projects radially outward from the outer diameter of the coil together with the coil wire at both the winding start and winding end. Projections 1a and 1b are provided as shown in FIG. 2 is a core rod, and in this example, the wire diameter is 0.6±
It is made of 0.006 mm tungsten wire. On the other hand, the coil 1 uses a tungsten wire with a wire diameter of 0.4 mm, and the initial inner diameter is set to 0.55 mm.

In order to assemble the coil 1 and the core rod 2 having such a configuration, first, a moment is applied to the protrusions 1a and 1b formed at both ends of the coil 1 in the direction in which the coil 1 is loosened. The inner diameter is made to be sufficiently larger than the outer diameter of the core rod 2. In this state, the core rod 2 is attached to the inner diameter of the coil 1.
is inserted, the coil 1 is placed at a predetermined position on the core rod 2, the moment applied to the protrusions 1a and 1b is removed, and then the protrusions 1a and 1b at both ends of the coil are cut off. As a result, an electrode in which the coil 1 is firmly coupled to a predetermined position of the core rod 2 is obtained. Note that the dotted line of the coil 1 in FIG. 1 indicates the outer diameter portion of the coil in an initial state where no moment is applied.

[0009] The bonding strength between the coil and the core rod of the electrode manufactured in this way was measured by the pressing force until the occurrence of displacement due to pressing, and the results were compared with those made by the conventional manufacturing method.The following results were obtained. was gotten. That is, the engagement strength of the product according to the present invention was 5.4 kg ± 1 kg, while that of the conventional example was 1.0 kg ± 0.8 kg, and the manufacturing method of the present invention resulted in an extremely strong joint. It was confirmed that a suitable electrode could be obtained. In the above measurement experiment,
The strength was measured for 1000 pieces of each.

[0010] Further, life tests and vibration tests were conducted, and the coil according to the present invention did not cause any displacement of the coil, and no other problems occurred.

Furthermore, even in mass production, by forming the protrusions at both ends of the coil at predetermined positions and at predetermined angles, the coil and core rod can be easily assembled by applying a moment, resulting in a highly accurate and strong electrode. It was confirmed that it can be easily mass-produced.

[0012] In the above embodiment, a double-wound coil was used as the coil, but even in the case of a single coil, the projections provided at both ends of the coil can be pushed apart using a cylindrical holding member or the like. The electrode core can be easily inserted into the inner diameter of the coil.

[0013]

[Effect of the invention] As explained above based on the embodiments,
According to the present invention, it is possible to easily manufacture a strong electrode for a discharge lamp that prevents the coil from falling or shifting without causing damage to the tip of the core rod.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a manufacturing process for explaining an embodiment of a method for manufacturing an electrode for a discharge lamp according to the present invention.

FIG. 2 is a diagram showing a manufacturing process for explaining a conventional method for manufacturing an electrode for a discharge lamp.

[Explanation of symbols]

1 Coil 1a, 1b Protrusion 2 Core rod

Claims (1)

[Claims] Claim 1: A method for manufacturing an electrode for a discharge lamp in which a coil is coupled to the tip of a core rod, in which the coil has an inner diameter smaller than the outer diameter of the core rod in a free state, and the coil winding start and end of the coil are provided. A protrusion is provided on both of the coil wires so as to protrude radially outward from the outer diameter part of the coil, and a moment is applied to the protrusion to increase the inner diameter of the coil, thereby increasing the inner diameter of the coil. 1. A method of manufacturing an electrode for a discharge lamp, comprising making the coil larger than the outer diameter of the coil, and then inserting a core rod into the inner diameter of the coil to connect the two.