JP2010272567A - Fixing method for magnetic core and structure of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To screw a male thread of a probe into a female thread hole of a core so as to simply join and fix them using laser welding. <P>SOLUTION: The fixing method and structure for a magnetic core is so disposed as to irradiate laser (22) onto a conical recessed part (21) formed at an outer circumference of a core (3) with a male thread (2) of a probe (1) screwed into a female thread hole (4) of the core (3), thus laser-welding the core (3) and the male thread (2) of the probe (1). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method and a structure for fixing a magnetic core, and more particularly to a novel improvement for easily connecting and fixing a male screw portion of a probe into a female screw hole of a core by laser welding.

As a fixing method and structure of this type of magnetic core that has been conventionally used, for example, in an LVDT (linear variable differential transformer) disclosed in Patent Documents 1 and 2 described later, it is shown in FIG. Was configured to be.
That is, what is indicated by reference numeral 1 in FIG. 5 is a long rod-like probe that is movably provided in a cylindrical stator (not shown) of the LVDT, and one end 1a of the probe 1 is integrally formed with the one end 1a. A male screw portion 2 that is formed and protrudes is formed.

A female screw hole 4 formed at one end 3 a of the core 3 is screwed into the male screw portion 2.
In the state where the male screw portion 2 of the probe 1 is screwed into the female screw hole 4 of the core 3, a silver solder 10 and an adhesive 11 are used to prevent loosening of the screw, and formed at this screwed portion. The bonded surface is fixed with silver brazing.

JP 2000-74607 A Japanese Patent Laid-Open No. 10-311737

Since the conventional magnetic core fixing method and structure are configured as described above, the following problems exist.
In other words, silver brazing that forms a silver solder at the joint formed on the screw threaded part of the probe and the core actually requires a lot of work processes and is difficult, and requires skill. And it took time.
In addition, the adhesive used for fixing the screwed portion of the probe and the core has a weak surface, and it has been difficult to obtain sufficient reliability.

  In the magnetic core fixing method according to the present invention, a probe having a long bar shape and a male screw portion formed at one end of the probe are screwed into a female screw hole at one end of the core to connect the probe and the core. In the fixing method of the magnetic core, a laser is irradiated to a conical recess formed on the outer periphery of the core and having a conical shape toward the axis of the core, and the core and the male screw portion of the probe are laser-welded. The male screw part and the female screw hole before the laser irradiation are a method in which only the screw connection is performed and no adhesive is provided, and the fixing structure of the magnetic core according to the present invention includes a probe having a longitudinal bar shape, In the fixing structure of the magnetic core that connects the probe and the core by screwing the male screw portion formed at one end of the probe into the female screw hole at one end of the core, the outer periphery of the core A laser is applied to a conical concave portion that is formed and forms a conical shape toward the axis of the core, and the male screw portion of the core and the probe are laser welded, and the male screw portion before the laser irradiation. The female screw hole has a configuration in which only the screw connection is provided and no adhesive is provided.

Since the magnetic core fixing method and structure according to the present invention are configured as described above, the following effects can be obtained.
That is, in the fixing method of the magnetic core for connecting the probe and the core by screwing a probe having a long rod shape and a male screw portion formed at one end of the probe into a female screw hole at one end of the core, Laser irradiation is performed on the conical concave portion formed on the outer periphery of the core and having a conical shape toward the axis of the core, and the core and the male screw portion of the probe are laser-welded. It becomes easy, and it becomes easy to fix the probe to the probe at a predetermined position, and the probe and the core can be easily fixed to each other.
Further, since the male screw portion and the female screw hole before the laser irradiation are merely screw-bonded and no adhesive is provided, a fixing structure that requires no adhesive can be obtained.

It is a block diagram which has a partial cross section which shows the fixing method and structure of a magnetic core by this invention. It is an expanded sectional view which shows the core of FIG. FIG. 3 is a plan view of FIG. 2. It is a block diagram which has a partial cross section which shows the state which formed the laser welding part in the core of FIG. It is a block diagram which has the partial cross section figure which shows the fixing method and structure of the conventional magnetic core.

  It is an object of the present invention to provide a magnetic core fixing method and structure in which a male screw portion of a probe is screwed into a female screw hole of a core and is simply coupled and fixed by laser welding.

Hereinafter, preferred embodiments of a magnetic core fixing method and structure according to the present invention will be described with reference to the drawings.
Note that the same or equivalent parts as in the conventional example will be described using the same reference numerals.
In FIG. 1, what is indicated by reference numeral 1 is a longitudinal bar-like probe that is movably provided in a cylindrical stator (not shown) of the LVDT, and is formed at one end 1a of the probe 1 integrally with the one end 1a. Thus, a protruding male screw portion 2 is formed.

A female screw hole 4 formed at one end 3 a of the core 3 is screwed into the male screw portion 2.
In the state where the male screw portion 2 of the probe 1 is screwed into the female screw hole 4 of the core 3, a laser welding portion 20 shown in FIG. 4 is formed to prevent loosening of the screw.
As shown in FIGS. 1 to 4, the laser welded portion 20 has a conical recess 21 formed on the outer peripheral surface 3 b of the core 3, and the conical center 21 a of the conical recess 21 faces the axis of the core 3. It is formed in a conical shape.

  As shown in FIG. 1, by irradiating the conical recess 21 with a laser 22 made of a YAG laser, the laser 22 is irradiated to the conical center 21a of the conical recess 21, as shown in FIG. The core 3 and a part of the male screw portion 2 are melted and integrated by heat, and the laser irradiation is stopped, so that the melted portion is solidified and becomes the laser welded portion 20. In the case of the laser welding described above, when the adhesive is applied to the connecting portion between the male screw portion 2 and the female screw hole 4 as in the conventional case, the adhesive is vaporized during laser irradiation, and a blow hole is easily formed. Since welding becomes difficult, only the screw connection is used and no adhesive is used.

  As shown in FIG. 4, the laser welded portion 20 is formed over each part of the core 3 and the male screw portion 2, so that the core 3 and the male screw portion 2 are firmly integrated, and the probe 1. It is configured so that it can sufficiently withstand long-term use as an LVDT.

  The fixing method and structure of the magnetic core according to the present invention are not limited to the connection between the magnetic core and the probe made of metal, but widely applied to the connection and fixing of the metal and the resin, the metal, and the male and female parts of the resin. Can do.

DESCRIPTION OF SYMBOLS 1 Probe 1a One end 2 Male screw part 3 Core 3a One end 3b Outer peripheral surface 4 Female screw hole 20 Laser welding part 21 Conical recessed part 22 Laser

Claims (4)

A probe (1) having a longitudinal rod shape and a male screw portion (2) formed at one end (1a) of the probe (1) are screwed into a female screw hole (4) at one end (3a) of the core (3). In the fixing method of the magnetic core that connects the probe (1) and the core (3),
A conical recess (21) formed on the outer periphery of the core (3) and having a conical shape toward the axis of the core (3) is irradiated with a laser (22), and the core (3) and the probe (1) A method for fixing a magnetic core, characterized by laser welding the male screw part (2).   2. The method of fixing a magnetic core according to claim 1, wherein the male screw portion (2) and the female screw hole (4) before the laser irradiation are merely screw-bonded and no adhesive is provided. A probe (1) having a longitudinal rod shape and a male screw portion (2) formed at one end (1a) of the probe (1) are screwed into a female screw hole (4) at one end (3a) of the core (3). In the fixing structure of the magnetic core that connects the probe (1) and the core (3),
A conical recess (21) formed on the outer periphery of the core (3) and having a conical shape toward the axis of the core (3) is irradiated with a laser (22), and the core (3) and the probe (1) A magnetic core fixing structure characterized by laser welding a male screw part (2).   The structure for fixing a magnetic core according to claim 3, wherein the male screw portion (2) and the female screw hole (4) before the laser irradiation are merely screw-bonded and no adhesive is provided.

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