Patent Description:
This application claims priority from <CIT>.

In order to fusion-splice two optical fibers, an optical fiber fusion-splicer is used. An optical fiber fusion-splicer fuses and splices the end faces of optical fibers using the thermal energy of an arc discharge from two electrode rods (for example, see <CIT>).

Further prior art is described in <CIT>.

In an optical fiber fusion-splicer, when electrical discharge is repeated, a pointed end of an electrode rod wears out and the electrode rod needs to be replaced. The wear can be delayed by increasing the diameter of the electrode rod; however this increases the costs of the electrode rod.

An object to be solved by an aspect of the invention is to provide an optical fiber fusion-splicer in which the above-mentioned costs and wear on the electrode rods can be reduced.

An optical fiber fusion-splicer according to one aspect of the invention which fusion-splices at least a pair of optical fibers includes a pair of electrode rod units of which pointed end portions are disposed to face each other with abutting portions of the optical fibers interposed therebetween, and a pair of mounting bases which respectively support the electrode rod units, in which each of the electrode rod units includes an electrode rod which fusion-splices the optical fibers by discharge heating, and a main heat dissipation member provided to protrude from an outer circumferential surface of the electrode rod, each of the mounting bases supports a position closer to a base end side than a pointed end portion of the electrode rod, the main heat dissipation member is provided in contact with the outer circumferential surface of the electrode rod over the whole circumference between the pointed end portion of the electrode rod and a front surface of the mounting base.

The main heat dissipation member is preferably formed of a metal.

In the optical fiber fusion-splicer, irregularities are preferably formed on a surface of the main heat dissipation member.

In the optical fiber fusion-splicer, it is preferable that an auxiliary heat dissipation member be provided on the outer circumferential surface of the electrode rod, and the auxiliary heat dissipation member is provided in contact with the outer circumferential surface of the electrode rod over the entire circumference on a side of the electrode rod closer to a base end of the electrode rod than the support position of the electrode rod supported by the mounting base.

The main heat dissipation member and the auxiliary heat dissipation member may be formed to be integrally connected with a connecting portion interposed therebetween.

According to one aspect of the invention, since the main heat dissipation member is provided, heat generated in the electrode rod can be transferred to the main heat dissipation member and an increase in temperature of the electrode rod can be reduced. Therefore, wear of the pointed end portion of the electrode rod can be reduced and a service life of the electrode rod can be prolonged. Further, according to one aspect of the invention, since there is no cost increase factor such as an increase in diameter of the electrode rod, costs can be reduced.

Hereinafter, an optical fiber fusion-splicer according to embodiments of the invention will be described with reference to the drawings.

<FIG> is a configuration diagram showing a portion of an optical fiber fusion-splicer including an electrode rod unit <NUM> according to a first embodiment. <FIG> is a perspective view showing the electrode rod unit <NUM>. <FIG> is a cross-sectional view showing the electrode rod unit <NUM>, a mounting base <NUM>, and an electrode rod presser <NUM>. <FIG> is a rear view showing the electrode rod unit <NUM>, the mounting base <NUM>, and the electrode rod presser <NUM>. <FIG> is a configuration diagram showing the whole of an optical fiber fusion-splicer <NUM> including the electrode rod unit <NUM>.

As shown in <FIG>, the optical fiber fusion-splicer <NUM> includes a main body <NUM>, a monitor <NUM>, and a windproof cover <NUM>. The monitor <NUM> displays images of ends of bare optical fibers <NUM> and <NUM>. The windproof cover <NUM> reduces the influence of wind by covering the electrode rod unit <NUM>, the mounting base <NUM> (see <FIG>), a fiber clamp <NUM>, and the like.

The main body <NUM> includes a pair of electrode rod units <NUM> and <NUM> (a first electrode rod unit and a second electrode rod unit), a pair of mounting bases <NUM> and <NUM> (a first mounting base and a second mounting base, see <FIG>), a pair of fiber clamps <NUM> and <NUM>, and a pair of electrode rod pressers <NUM> and <NUM> (see <FIG>).

As shown in <FIG> and <FIG>, each of the electrode rod units <NUM> includes an electrode rod <NUM> and a main heat dissipation member <NUM> (a first heat dissipation member).

The electrode rod <NUM> is formed of a metal such as tungsten, for example. The electrode rod <NUM> includes a cylindrical body <NUM> and a conical pointed end portion <NUM>. The pointed end portion <NUM> is formed to gradually taper in a direction away from the cylindrical body <NUM>. An end portion of the electrode rod <NUM> on a side opposite to the pointed end portion <NUM> is referred to as a base end portion <NUM>. A direction from the base end portion <NUM> toward the pointed end portion <NUM> is forwards and a direction opposite thereto is rearwards. As shown in <FIG>, a reference sign C1 is a central axis of the electrode rod <NUM>. A reference sign C2 is a central axis of the main heat dissipation member <NUM>. 12a is a front surface of the main heat dissipation member <NUM>.

As shown in <FIG>, the electrode rod <NUM> (first electrode rod) of one electrode rod unit <NUM> (first electrode rod unit) and the electrode rod <NUM> (second electrode rod) of the other electrode rod unit <NUM> (second electrode rod unit) are disposed so that the pointed end portions <NUM> thereof face each other. The electrode rod <NUM> fusion-splices the bare optical fibers <NUM> and <NUM> by heating using an arc discharge.

The main heat dissipation member <NUM> is annular and has an insertion hole <NUM> through which the electrode rod <NUM> is inserted. An inner circumferential surface of the insertion hole <NUM> is in contact with the outer circumferential surface of the cylindrical body <NUM> over the whole circumference.

The main heat dissipation member <NUM> protrudes outward in a radial direction from the outer circumferential surface of the electrode rod <NUM>. The main heat dissipation member <NUM> is attached and fixed to the cylindrical body <NUM>, for example, by press-fitting or the like.

A constituent material of the main heat dissipation member <NUM> may be a metal such as aluminum, an aluminum alloy, a zinc alloy, tungsten, or the like. Zinc alloys include ZDC2 (in accordance with JIS H <NUM>: <NUM>), ZDC3, and the like. When the main heat dissipation member <NUM> is made of a metal, an amount of heat transferred from the electrode rod <NUM> can be increased, and thus an increase in temperature of the electrode rod <NUM> can be reduced.

When the constituent material of the main heat dissipation member <NUM> is a zinc alloy or an aluminum alloy, breakage of the main heat dissipation member <NUM> does not easily occur. The following conjecture is possible for the reason why breakage of the main heat dissipation member <NUM> does not easily occur. When a temperature of the electrode rod <NUM> (made of, for example, tungsten) reaches a high temperature, an outer diameter of the electrode rod <NUM> increases due to thermal expansion and an inner diameter of the main heat dissipation member <NUM> decreases. However, since the main heat dissipation member <NUM> has a relatively low rigidity and conforms to deformation of the electrode rod <NUM>, breakage of the main heat dissipation member <NUM> at a portion in contact with the electrode rod <NUM> can be avoided.

A thermal conductivity of the main heat dissipation member <NUM> can be, for example, <NUM> W/(m·K) or more. As a method for measuring the thermal conductivity, for example, there is a method specified in JIS R <NUM> and the like.

As shown in <FIG>, the main heat dissipation member <NUM> is provided on a side in front of a support position <NUM> of the electrode rod <NUM> supported by the mounting base <NUM>. That is, the main heat dissipation member <NUM> is provided between the pointed end portion <NUM> of the electrode rod <NUM> and the support position <NUM>. In the electrode rod unit <NUM>, a rear surface 12b of the main heat dissipation member <NUM> is in contact with a front surface 2a of the mounting base <NUM>, and thereby rearward movement of the electrode rod unit <NUM> is restricted.

The main heat dissipation member <NUM> may be fixed to the cylindrical body <NUM> with an adhesive. Examples of the adhesive which can be used include a heat-resistant inorganic adhesive (for example, Aron Ceramic or the like manufactured by Toagosei Co. ), a heat-resistant epoxy adhesive (for example, Aremco-Bond <NUM>, Aremco Bond <NUM>-N, or the like manufactured by Audec Corporation), a heat-resistant liquid gasket silicone-based adhesive (for example, TB1209H, or the like), an anaerobic high-strength adhesive, and the like.

As shown in <FIG> and <FIG>, the mounting base <NUM> includes a mounting surface <NUM> having a holding groove <NUM>. The holding groove <NUM> has, for example, a V-shaped cross section. The holding groove <NUM> allows the cylindrical body <NUM> of the electrode rod <NUM> to be fitted thereto and thus can position the electrode rod <NUM>. The mounting base <NUM> supports a position on a rear side (base end side) of the pointed end portion <NUM> in the electrode rod <NUM>. An inner surface of the holding groove <NUM> is made of, for example, a metal and may be capable of supplying power to the electrode rod unit <NUM>.

The fiber clamps <NUM> and <NUM> in <FIG> grip and position the bare optical fibers <NUM> and <NUM> of a pair of optical fibers <NUM> and <NUM> when the windproof cover <NUM> is closed.

As shown in <FIG>, <FIG> and <FIG>, the electrode rod presser <NUM> is formed, for example, in a rectangular plate shape. The electrode rod presser <NUM> is formed of a metal such as aluminum, for example. The electrode rod presser <NUM> can position the electrode rod <NUM> on the mounting base <NUM> by pressing the electrode rod <NUM>. The electrode rod presser <NUM> can be fixed to the mounting base <NUM> using a fixing tool which is not shown in drawings. The electrode rod presser <NUM> can supply power to the electrode rod unit <NUM>.

As shown in <FIG>, in the electrode rod units <NUM> and <NUM>, the pointed end portions <NUM> and <NUM> are disposed to face each other with the abutting portions of ends 91a and 91a of the bare optical fibers <NUM> and <NUM> interposed therebetween. In the optical fiber fusion-splicer <NUM>, power is supplied to the electrode rod units <NUM> and <NUM> so that the ends 91a and 91a of the bare optical fibers <NUM> and <NUM> are fusion-spliced by discharge heating.

Since the electrode rod unit <NUM> has the main heat dissipation member <NUM>, heat generated by the electrode rod <NUM> can be transferred to the main heat dissipation member <NUM> and released to the atmosphere. Therefore, an increase in temperature of the electrode rod <NUM> can be reduced. Therefore, wear of the pointed end portion <NUM> of the electrode rod <NUM> can be reduced and a service life of the electrode rod <NUM> can be prolonged. Since the electrode rod unit <NUM> has no cost increase factor such as an increase in diameter of the electrode rod <NUM>, costs can be reduced.

Since the main heat dissipation member <NUM> is in contact with the outer circumferential surface of the electrode rod <NUM> over the whole circumference, a deviation in temperature in the circumferential direction of the electrode rod <NUM> does not easily occur. Therefore, wrapping deformation of the electrode rod <NUM> can be reduced. Therefore, a decrease in accuracy of the fusion splicing caused by positional deviation of the pointed ends of the electrode rods <NUM> can be prevented.

In the electrode rod unit <NUM>, since the main heat dissipation member <NUM> is in contact with the front surface 2a of the mounting base <NUM> to restrict rearward movement, a configuration for positioning the electrode rod unit <NUM> in a front-rear direction is unnecessary. Therefore, a device configuration is simplified and costs can be reduced.

<FIG> is a cross-sectional view showing an electrode rod unit 1A according to a second embodiment. <FIG> is a cross-sectional view showing the electrode rod unit 1A, a mounting base <NUM>, and an electrode rod presser <NUM>. Further, components the same as in the other embodiments are denoted by the same reference signs, and descriptions thereof will be omitted.

As shown in <FIG>, the electrode rod unit 1A is different from the electrode rod unit <NUM> according to the first embodiment shown in <FIG> in that a positioning member <NUM> is provided at a portion including a base end portion <NUM> of an electrode rod <NUM>. The positioning member <NUM> is formed in a cylindrical shape (or disc shape) having an outer diameter larger than that of the electrode rod <NUM>. The positioning member <NUM> is formed of a resin or the like.

Forward movement of the electrode rod unit 1A is restricted due to a front surface 21a of the positioning member <NUM> being in contact with a rear surface 2b of the mounting base <NUM>.

As in the first embodiment, the electrode rod unit 1A can prevent an increase in temperature of the electrode rod <NUM>.

Therefore, wear of a pointed end portion <NUM> of the electrode rod <NUM> can be reduced and a service life of the electrode rod <NUM> can be prolonged. Further, since there is no cost increase factor such as an increase in diameter of the electrode rod <NUM>, cost can be reduced.

In the electrode rod unit 1A, since a main heat dissipation member <NUM> is in contact with an outer circumferential surface of the electrode rod <NUM> over the whole circumference, a deviation in temperature in a circumferential direction of the electrode rod <NUM> does not easily occur, and thus wrapping deformation of the electrode rod <NUM> can be reduced. Therefore, a decrease in accuracy of the fusion splicing caused by positional deviation of pointed ends of the electrode rods <NUM> can be prevented.

Since positioning of the electrode rod unit 1A in a front-rear direction is possible due to the positioning member <NUM>, a device configuration is simplified and costs can be reduced.

<FIG> is a cross-sectional view showing an electrode rod unit 1B according to a third embodiment. <FIG> is a cross-sectional view showing the electrode rod unit 1B, a mounting base <NUM>, and an electrode rod presser <NUM>. Further, components the same as in the other embodiments are denoted by the same reference signs, and descriptions thereof will be omitted.

As shown in <FIG>, the electrode rod unit 1B is different from the electrode rod unit <NUM> according to the first embodiment shown in <FIG> in that an auxiliary heat dissipation member <NUM> (second heat dissipation member) is provided at a position close to a base end portion <NUM> of the electrode rod <NUM>. The auxiliary heat dissipation member <NUM> is formed in an annular shape having an outer diameter larger than that of the electrode rod <NUM>.

The auxiliary heat dissipation member <NUM> is, for example, annular, and is provided on an outer circumferential surface of a cylindrical body <NUM> of the electrode rod <NUM>. The auxiliary heat dissipation member <NUM> protrudes outward in a radial direction from the outer circumferential surface of the cylindrical body <NUM>. A front surface 22a and a rear surface 22b of the auxiliary heat dissipation member <NUM> are, for example, perpendicular to a central axis of the auxiliary heat dissipation member <NUM>. The auxiliary heat dissipation member <NUM> is a separate body from the electrode rod <NUM>. The auxiliary heat dissipation member <NUM> has an outer diameter larger than that of the electrode rod <NUM>.

The auxiliary heat dissipation member <NUM> has an insertion hole <NUM> through which the electrode rod <NUM> is inserted. An inner circumferential surface of the insertion hole <NUM> is in contact with an outer circumferential surface of the cylindrical body <NUM> over a circumferential direction (specifically, over the whole circumference). The entire inner circumferential surface of the insertion hole <NUM> is preferably in contact with the outer circumferential surface of the cylindrical body <NUM>. The auxiliary heat dissipation member <NUM> is attached and fixed to the cylindrical body <NUM>, for example, by press-fitting or the like. Material and physical property values of the auxiliary heat dissipation member <NUM> may be the same as those of a main heat dissipation member <NUM>.

The auxiliary heat dissipation member <NUM> is provided closer to a rear side (base end side) than a support position <NUM>.

Forward movement of the electrode rod unit 1B is restricted due to the front surface 22a of the auxiliary heat dissipation member <NUM> being in contact with a rear surface 2b of the mounting base <NUM>.

As in the first embodiment, the electrode rod unit 1B can prevent an increase in temperature of the electrode rod <NUM>. Therefore, wear of a pointed end portion <NUM> of the electrode rod <NUM> can be reduced and a service life of the electrode rod <NUM> can be prolonged. Further, since there is no cost increase factor such as an increase in diameter of the electrode rod <NUM>, cost can be reduced.

In the electrode rod unit 1B, since the main heat dissipation member <NUM> and the auxiliary heat dissipation member <NUM> are in contact with an outer circumferential surface of the electrode rod <NUM> over the whole circumference, a deviation in temperature in a circumferential direction of the electrode rod <NUM> does not easily occur, and thus wrapping deformation of the electrode rod <NUM> can be reduced. Therefore, a decrease in accuracy of the fusion splicing caused by positional deviation of pointed ends of the electrode rods <NUM> can be prevented.

Since positioning of the electrode rod unit 1B in a front-rear direction is possible due to the auxiliary heat dissipation member <NUM>, a device configuration is simplified and costs can be reduced.

<FIG> is a cross-sectional view showing an electrode rod unit 1C according to a fourth embodiment. <FIG> is a cross-sectional view showing the electrode rod unit 1C, a mounting base <NUM>, and an electrode rod presser <NUM>. Further, components the same as in the other embodiments are denoted by the same reference signs, and descriptions thereof will be omitted.

As shown in <FIG>, the electrode rod unit 1C is different from the electrode rod unit 1B according to the third embodiment in that a main heat dissipation member <NUM> and an auxiliary heat dissipation member <NUM> are formed to be integrally connected with a connecting portion <NUM> interposed therebetween.

As in the first embodiment, the electrode rod unit 1C can prevent an increase in temperature of an electrode rod <NUM>. Therefore, wear of a pointed end portion <NUM> of the electrode rod <NUM> can be reduced and a service life of the electrode rod <NUM> can be prolonged. Further, since there is no cost increase factor such as an increase in diameter of the electrode rod <NUM>, costs can be reduced.

In the electrode rod unit 1C, since the main heat dissipation member <NUM> and the auxiliary heat dissipation member <NUM> are in contact with an outer circumferential surface of the electrode rod <NUM> over the whole circumference, a deviation in temperature in a circumferential direction of the electrode rod <NUM> does not easily occur, and thus wrapping deformation of the electrode rod <NUM> can be reduced. Therefore, a decrease in accuracy of the fusion splicing caused by positional deviation of pointed ends of the electrode rods <NUM> can be prevented.

Since positioning of the electrode rod unit 1C in a front-rear direction is possible due to the auxiliary heat dissipation member <NUM>, a device configuration is simplified and costs can be reduced.

In the electrode rod unit 1C, a temperature of the main heat dissipation member <NUM> closer to the pointed end portion <NUM> tends to be higher than that of the auxiliary heat dissipation member <NUM>. However, since an amount of heat transferred from the main heat dissipation member <NUM> to the auxiliary heat dissipation member <NUM> can be increased by the connecting portion <NUM>, an increase in temperature of the electrode rod <NUM> can be reduced by preventing an increase in temperature of the main heat dissipation member <NUM>.

<FIG> is a perspective view showing an electrode rod unit 1D which is a specific example of the electrode rod unit 1C according to the fourth embodiment. <FIG> is a perspective view showing the electrode rod unit 1D viewed from a side opposite to <FIG>. Further, components the same as in the other embodiments are denoted by the same reference signs, and descriptions thereof will be omitted.

In the electrode rod unit 1D, a main heat dissipation member 12D and an auxiliary heat dissipation member 22D are formed to be integrally connected with a connecting portion 23D interposed therebetween. The main heat dissipation member 12D and the auxiliary heat dissipation member 22D are formed in a rectangular plate shape. The connecting portion 23D is formed in a plate shape.

Claim 1:
An optical fiber fusion-splicer (<NUM>) which fusion-splices at least a pair of optical fibers (<NUM>), comprising:
a pair of electrode rod units (<NUM>) of which pointed end portions are disposed to face each other with abutting portions (91a) of the optical fibers (<NUM>) interposed therebetween; and
a pair of mounting bases (<NUM>) which respectively support the electrode rod units (<NUM>), wherein
each of the electrode rod units (<NUM>) includes:
an electrode rod (<NUM>) which fusion-splices the optical fibers (<NUM>) by discharge heating: and
a main heat dissipation member (<NUM>) provided to protrude from an outer circumferential surface of the electrode rod (<NUM>), and
each of the mounting bases (<NUM>) supports the electrode rod (<NUM>) at a position closer to a base end side of the electrode rod (<NUM>) than a pointed end portion of the electrode rod (<NUM>),
characterized in that
the main heat dissipation member (<NUM>) is provided in contact with the outer circumferential surface of the electrode rod (<NUM>) over the whole circumference between the pointed end portion (<NUM>) of the electrode rod (<NUM>) and a front surface (2a) of the mounting base (<NUM>).