Contact terminal, inspection jig, and inspection apparatus

A contact terminal includes a tubular body and a first conductor. The tubular body has an end-side cutout provided in a shape cut out from one axial-direction end surface toward an other axial-direction side at one axial-direction end portion of the tubular body, a hole that is open at the one axial-direction end portion, and a pair of arms interposed between the end-side cutout and the hole. The first conductor includes a first insertion including an inclined portion having an outside diameter gradually increased toward one axial-direction side, and a first straight portion connected to the one axial-direction side of the inclined portion and having an outside diameter constant along the axial direction. The outside diameter of the first straight portion is larger than an inside diameter of the tubular body. The first straight portion is configured to be in contact with the pair of arms.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a U.S. National Stage Application No. of International Application PCT/JP2021/009931, filed on Mar. 11, 2021, and claims priority under 35 U.S.C. § 119(a) and 35 U.S.C. § 365(b) from Japanese Patent Application No. 2020-049472, filed on Mar. 19, 2020; the disclosures of which are incorporated herein by reference.

FIELD

Various embodiments of the present disclosure relate to a contact terminal used for inspecting an inspection target.

BACKGROUND

Conventionally, a contact terminal to be brought into contact with an inspection target is known. Such a contact terminal is configured by inserting a rod-shaped member having conductivity into a tubular body including a spring at an intermediate position.

In the contact terminal, the rod-shaped member is fastened to a distal end of the tubular body in a state in which an end of the rod-shaped member protrudes from the tubular body. As an example of a method of performing such fastening, a contact terminal in which a rod-shaped member is fastened to a tubular body by press fitting is known.

However, in the contact terminal in which the rod-shaped member is fastened by press fitting as described above, there is room for improvement in assemblability of the rod-shaped member to the tubular body.

SUMMARY

An exemplary contact terminal of the present disclosure includes a tubular body elongated in an axial direction of the contact terminal and having conductivity, and a first conductor having conductivity and a rod shape.

The tubular body has an end-side cutout provided in a shape cut out from one axial-direction end surface toward another axial-direction side at one axial-direction end portion of the tubular body, a hole that is open at the one axial-direction end portion, and a pair of arms interposed between the end-side cutout and the hole.

The first conductor includes a first protrusion protruding from the tubular body toward one axial-direction side, and a first insertion connected to another axial-direction side of the first protrusion and disposed inside the tubular body.

The first insertion includes an inclined portion having an outside diameter gradually increased toward the one axial-direction side, and a first straight portion connected to one axial-direction side of the inclined portion and having an outside diameter constant along the axial direction.

The outside diameter of the first straight portion is larger than an inside diameter of the tubular body. The first straight portion is configured to be in contact with the pair of arms. The first straight portion includes a wall surface disposed at one axial-direction end of the first straight portion and contactable with the hole.

DETAILED DESCRIPTION

Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the drawings. In the following, a direction parallel to a central axis J (seeFIG.2) of a contact terminal is referred to by the term “axial direction”, “axial”, or “axially”. In the drawings, with the axial direction being defined as X, X1 represents one axial-direction side and X2 represents the other axial-direction side. Moreover, in the drawings, with a direction perpendicular to the axial direction X being defined as a first direction Y, Y1 represents one first-direction side and Y2 represents the other first-direction side. As will be described later, in a tubular body20, an end-side cutout31side is one first-direction Y1 side, and a hole32side is the other first-direction Y2 side. Moreover, in the drawings, with a direction perpendicular to the axial direction X and the first direction Y being defined as a second direction Z, Z1 represents one second-direction side and Z2 represents the other second-direction side. In addition, a direction about the central axis J will be referred to by the term “circumferential direction”, “circumferential”, or “circumferentially”.

An overall configuration of an inspection apparatus10according to an exemplary embodiment of the present disclosure will be described with reference toFIG.1. Referring toFIG.1, a contact terminal2is assembled to the inspection apparatus10such that one axial-direction X1 side is a lower side.

The inspection apparatus10illustrated inFIG.1electrically inspects an inspection target100. The inspection apparatus10includes an inspection jig8and an inspection processor9. The inspection jig8is configured as, for example, a so-called probe card.

The inspection target100is, for example, a semiconductor wafer in which a plurality of circuits is formed on a semiconductor substrate such as silicon. The semiconductor wafer is diced to be divided into semiconductor chips having the individual circuits. In addition to the semiconductor wafer, the inspection target100can be, for example, an electronic component such as a semiconductor chip, a chip size package (CSP), a wafer level package (WLP), a fan out wafer level package (FOWLP), or a semiconductor element.

The inspection target100may also be a board. In this case, the inspection target100may be, for example, a board such as a printed circuit board, a glass epoxy board, a flexible board, a ceramic multilayer circuit board, a package board for a semiconductor package, an interposer board, or a film carrier. The inspection target100may alternatively be an electrode plate for a display such as a liquid crystal display, an electro-luminescence (EL) display, or a touch screen display, or an electrode plate for a touch screen.

Alternatively, the inspection target100may be a product obtained by packaging technology called embedded multi-die interconnect bridge (EMIB). According to EMIB, a small silicon substrate called a silicon bridge is embedded in a package resin board, and fine wires are formed on a surface of the silicon bridge in high density, so that adjacent silicon dies are mounted on the package resin board in proximity to each other.

As illustrated inFIG.1, the inspection jig8includes a probe head1, a pitch conversion unit6, and a connection plate7. The probe head1includes the contact terminal (probe)2and a support member3.

The inspection jig8includes a plurality of contact terminals2and the support member3that supports the plurality of contact terminals2.

The pitch conversion unit6is disposed above the support member3and fastened to the support member3. The contact terminal2includes one end2A on the one axial-direction X1 side and the other end2B on the other axial-direction X2 side. The other end2B is connected to each of first electrodes61(seeFIG.5) provided at a lower end of the pitch conversion unit6.

The pitch conversion unit6converts a first pitch between the contact terminals2into a second pitch between second electrodes formed at an upper end of the pitch conversion unit6. The second pitch is longer than the first pitch. For example, the pitch conversion unit6is made up of a multilayer circuit board such as a multi-layer organic (MLO) or a multi-layer ceramic (MLC).

The connection plate7is configured such that the pitch conversion unit6can be detached therefrom and attached thereto. The pitch conversion unit6is electrically connected to the inspection processor9via the connection plate7.

For example, the inspection processor9includes a power supply circuit, a voltmeter, an ammeter, and a microcomputer. The inspection processor9causes a drive mechanism (not illustrated) to move the inspection jig8relative to the inspection target100.

In a case where the inspection target100is, for example, a semiconductor wafer, inspection points such as pads or bumps are formed for each circuit corresponding to an individual semiconductor chip to be obtained by dicing the inspection target100. The inspection processor9defines a certain region of the plurality of circuits on the inspection target100as an inspection region, and moves the inspection jig8relative to a position at which the contact terminals2located above are opposite the inspection points located below in the inspection region. At this time, the one ends2A of the contact terminals2of the inspection jig8are directed toward the inspection target100.

Then, the inspection processor9moves the inspection jig8downward to bring the contact terminals2into contact with the inspection points in the inspection region. In this manner, the inspection points are electrically connected to the inspection processor9.

The inspection processor9supplies a current for inspection or a voltage for inspection to each inspection point of the inspection target100via each contact terminal2in the foregoing state, and inspects the inspection target100based on a voltage signal or a current signal obtained from each contact terminal2.

That is, the inspection apparatus10includes the inspection jig8and the inspection processor9configured to inspect the inspection target100based on an electrical signal obtained by bringing the contact terminal2into contact with the inspection point provided in the inspection target100.

After completion of the inspection on the inspection region in the inspection target100, the inspection processor9moves the inspection jig8upward, translates the inspection jig8to a position corresponding to a new inspection region, moves the inspection jig8downward, and brings the contact terminals2into contact with the inspection points in the new inspection region, thus performing the inspection. In this manner, the entire inspection target100is inspected by performing the inspection while sequentially changing the inspection region.

Hereinafter, the configuration of the contact terminal2will be described in more detail.FIGS.2and3each illustrate a case where no load is applied to the contact terminal2and a first spring22and a second spring23are in a natural length state.

The contact terminal2includes the tubular body20elongated in the axial direction of the contact terminal2and having conductivity, a first conductor (plunger)40having conductivity and a rod shape, and a second conductor (plunger)50having conductivity and a rod shape. The first conductor40and the second conductor50are formed of, for example, a conductive material such as a palladium alloy.

The tubular body20has a cylindrical shape and is formed from, for example, a nickel tube or a nickel-alloy tube having an outside diameter of about 25 μm to 300 μm and an inside diameter of about 10 μm to 250 μm. For example, the tubular body20has, on its inner peripheral surface, a conductive layer such as a gold plating layer. This can reduce contact resistance at a sliding contact point CP (FIG.4) to be described later. In addition, the tubular body20may have an outer peripheral surface coated with an insulation coating as necessary.

The tubular body20includes a first body21, the first spring22, the second spring23, and a second body24. The first body21, the first spring22, the second body24, and the second spring23are arranged in this order from the one axial-direction X1 side to the other axial-direction X2 side.

The first spring22and the second spring23are each formed as a helical body elongated in a helical shape along the peripheral surface of the tubular body20. The first body21and the second body24each have a tubular shape that is not formed in a helical shape.

In order to produce a tubular body having such a helical body, for example, a gold plating layer is formed by plating on an outer periphery of a core material, and then a nickel electroforming layer is formed by electroforming on an outer periphery of the formed gold plating layer. A resist layer is formed on an outer periphery of the nickel electroforming layer, and then is exposed with a laser, so that the resist layer is partially removed in a helical shape. Etching is performed using the resist layer as a masking material to remove the nickel electroforming layer at the position where the resist layer is helically removed. Then, after removing the resist layer, the gold plating layer is removed at the position where the nickel electroforming layer is helically removed, and the core material is removed while the gold plating layer is left on an inner periphery of the nickel electroforming layer, thus producing a tubular body.

The first conductor40includes a first protrusion41and a first insertion42(FIG.3). The first protrusion41protrudes from the tubular body20toward the one axial-direction X1 side. The first insertion42is connected to the other axial-direction X2 side of the first protrusion41and disposed inside the tubular body20. The first conductor40and the second conductor50each have a rotating body shape around the axial direction. Thus, the first conductor40and the second conductor50can be formed by cutting using a lathe.

The first protrusion41includes a rod-shaped main body411and a flange412connected to the other axial-direction X2 side of the rod-shaped main body411. The rod-shaped main body411includes a distal end411A on the one axial-direction X1 side. The distal end411A is brought into contact with each inspection point of the inspection target100as described later.

In the example ofFIG.3, the distal end411A has a conical shape, but is not limited thereto. For example, the distal end411A may have a truncated cone shape, a hemispherical shape, a circular cylinder shape, or the like.

The first insertion42is connected to the other axial-direction X2 side of the flange412and is fastened to the first body21. More specifically, the first insertion42is fastened to one axial-direction end portion201of the tubular body20. The one axial-direction end portion201is included in the first body21. A fastening structure for fastening the first insertion42to the first body21will be described later.

The second conductor50includes a second protrusion51and a second insertion52disposed inside the tubular body20(FIG.3). The second insertion52is connected to the one axial-direction X1 side of the second protrusion51. The second insertion52is fastened to the other axial-direction end portion202of the tubular body20. A fastening structure for fastening the second insertion52to the tubular body20will be described later.

In this manner, the first conductor40and the second conductor50are fastened to the tubular body20, thus forming the contact terminal2.

As illustrated inFIG.3, the second insertion52is elongated in the axial direction to the first body21through the second spring23, the second body24, and the first spring22inside the tubular body20. Consequently, the second insertion52is in contact with the first body21.

FIG.4illustrates a state in which the first spring22and the second spring23are compressed by applying a load to the contact terminal2. In this case, the second conductor50moves to the one axial-direction X1 side relative to the first conductor40as compared with the state ofFIG.3. Consequently, the second insertion52moves to the one axial-direction X1 side while being in contact with the first body21. Meanwhile, the first insertion42is fastened to the first body21. Thus, the contact between the second insertion52and the first body21forms a sliding contact point CP. The contact terminal2has a current path through the first insertion42, the first body21, the sliding contact point CP, and the second insertion52.

Moreover, as illustrated inFIG.3, the contact terminal2, which includes the first conductor40of reduced axial length and the second conductor50of increased axial length, can reduce a difference between both lengths. Consequently, the first conductor40and the second conductor50can be easily produced.

FIG.5is a view illustrating a state in which the contact terminal2is supported by the support member3. As illustrated inFIG.5, the support member3includes an upper support body301, an intermediate support body302, and a lower support body303. Here, a configuration in which the contact terminal2is supported by the support member3will be described.

The lower support body303has a support hole303A which is a through hole passing through the lower support body303in a thickness direction. The support hole303A has an axially-viewed sectional area slightly larger than an axially-viewed sectional area of the rod-shaped main body411and smaller than an axially-viewed sectional area of the flange412. This allows the rod-shaped main body411to be inserted into the support hole303A, and allows the flange412to prevent the contact terminal2from falling off.

The intermediate support body302is disposed above the lower support body303and has a support hole302A which is a through hole coaxial with the support hole303A. The support hole302A has an axially-viewed sectional area slightly larger than an axially-viewed outer sectional area of the second body24. This allows the second body24to be inserted into the support hole302A.

The upper support body301is disposed above the intermediate support body302and has a support hole301A which is a through hole coaxial with the support hole302A. The support hole301A has an axially-viewed sectional area slightly larger than axially-viewed outer sectional areas of the other axial-direction end portion202of the tubular body20and the second protrusion51. This allows the other axial-direction end portion202and the second protrusion51to be inserted into the support hole301A.

When the contact terminal2is supported by the support member3, the rod-shaped main body411is sequentially inserted into the support hole301A, the support hole302A, and the support hole303A from above. The support holes301A and302A each have an axially-viewed section that allows the flange412to be inserted therethrough.

In a state in which the contact terminal2is supported by the support member3as described above, the rod-shaped main body411is received in the support hole303A. The flange412is brought into contact with an upper surface303B of the lower support body303. The second body24is received in the support hole302A. The other axial-direction end portion202and the second protrusion51are received in the support hole301A.

Then, an upper surface of the upper support body301is pressed against a lower surface of the pitch conversion unit6while bringing a distal end511of the second protrusion51into contact with the first electrode61exposed on the lower surface of the pitch conversion unit6. Thus, the support member3is fastened to the pitch conversion unit6. At this time, the first spring22and the second spring23are axially compressed. This allows the distal end511to be pressed against the first electrode61by the elastic force of the springs22and23, and allows the distal end511and the first electrode61to be held in a stable conductive contact state.

Furthermore, in inspecting the inspection target100, the distal end411A of the rod-shaped main body411is brought into contact with an inspection point100A of the inspection target100. At this time, a force toward the other axial-direction X2 side is applied to the distal end411A, and the first spring22and the second spring23are axially compressed. This allows the distal end411A to be pressed against the inspection point100A by the elastic force of the springs22and23, and allows the distal end411A and the inspection point100A to be held in a stable conductive contact state.

In the contact terminal2, the spring includes the first spring22and the second spring23disposed on the other axial-direction X2 side with respect to the first spring22, and the tubular body20includes the second body24disposed between the first spring22and the second spring23and not formed in a helical shape. This allows the second body24located in the middle of the tubular body20to be supported by the intermediate support body302, and can provide less buckling of the tubular body20.

A description will now be given of a first embodiment of a fastening structure for fastening the first conductor40of the contact terminal2to the tubular body20.FIGS.6and7are views each illustrating an exploded state before the first conductor40is fastened to the tubular body20.

The one axial-direction end portion201of the tubular body20has an end-side cutout31and a hole32.

The end-side cutout31(FIG.6) is formed in a shape cut out toward the other axial-direction X2 side from one axial-direction end surface201A of the one axial-direction end portion201. The hole32(FIG.7) is open at the one axial-direction end portion201. The end-side cutout31is provided on the one first-direction Y1 side. The hole32is provided on the other first-direction Y2 side. A circumferential center position of the end-side cutout31is circumferentially shifted by 180° with respect to a circumferential center position of the hole32. However, the two circumferential center positions may be slightly shifted from 180°.

That is, the tubular body20has the end-side cutout31provided in the shape cut out from the one axial-direction end surface201A toward the other axial-direction X2 side at the one axial-direction end portion201of the tubular body20; and the hole32which is open at the one axial-direction end portion201.

The first insertion42(FIG.6) of the first conductor40includes an inclined portion421, a first straight portion422, a narrow portion423, and a second straight portion424. The inclined portion421has an outside diameter gradually increased toward the one axial-direction X1 side. The first straight portion422is connected to the one axial-direction X1 side of the inclined portion421, and has an outside diameter constant along the axial direction.

The first straight portion422has an outside diameter D2larger than an inside diameter D1of the tubular body20(FIG.6).

The narrow portion423is connected to the one axial-direction X1 side of the first straight portion422and is connected to the other axial-direction X2 side of the flange412. The narrow portion423has an outside diameter smaller than the outside diameter of the first straight portion422.

The second straight portion424is connected to the other axial-direction X2 side of the inclined portion421, and has an outside diameter constant along the axial direction.

When the first conductor40is assembled to the tubular body20, the second straight portion424is inserted into the tubular body20from the one axial-direction end surface201A. As the insertion proceeds, the inclined portion421comes into contact with an inner periphery of the one axial-direction end surface201A. As the first conductor40is pushed in as it is, the one axial-direction end portion201expands, and the first straight portion422is inserted into the tubular body20.

As the insertion further proceeds, the flange412comes into contact with the one axial-direction end surface201A, thus restricting the insertion of the first conductor40.FIGS.8and9each illustrate a state in which the first conductor40is pushed into the tubular body20and the flange412is in contact with the one axial-direction end surface201A.FIG.8illustrates a state in which the first conductor40is inserted into the tubular body20inFIG.6.FIG.9illustrates a state in which the first conductor40is inserted into the tubular body20inFIG.7.

In the states illustrated inFIGS.8and9, the first straight portion422is pinched from both sides in the second direction Z by a pair of arms211and212of the tubular body20. The arms211and212are interposed between the end-side cutout31and the hole32.

Since the outside diameter D2of the first straight portion422is larger than the inside diameter D1of the tubular body20, the first straight portion422is pressed by the pair of arms211and212. That is, the first straight portion422is in contact with the arms211and212. This allows the first conductor40to be fastened to the tubular body20.

A wall surface425is formed in the level-difference portion between the first straight portion422and the narrow portion423(FIG.6). Here, as illustrated inFIG.9, a distance L1between the wall surface425and the flange412is longer than a distance L2between the hole32and the one axial-direction end surface201A. Consequently, in the state ofFIG.9, the narrow portion423is fitted between the hole32and the one axial-direction end surface201A. The wall surface425is contactable with an axially protruding edge321included in the hole32. The axially protruding edge321is an edge of an axial protrusion201B protruding toward the other axial-direction X2 side at the one axial-direction end portion201.

That is, the wall surface425disposed at the one axial-direction end of the first straight portion422is contactable with the hole32. This allows the first conductor40assembled to the tubular body20to be less likely to come off from the tubular body20. In addition, since the wall surface425is contactable with the axially protruding edge321(FIG.7), the first conductor40is much less likely to come off from the tubular body20. Furthermore, it is possible to prevent the wall surface425from being in contact with a portion near both circumferential ends of the axially protruding edge321.

Here, as illustrated inFIG.19, if the one axial-direction end portion201of a tubular body20X has no hole but only an end-side cutout S20, a state in which the first conductor40is assembled to the tubular body20X is as illustrated inFIG.20. At this time, the one axial-direction end portion201having only the end-side cutout S20results in little expansion at the time of inserting the first conductor40into the tubular body20X.

On the other hand, in the contact terminal2according to the present embodiment, since the tubular body20has the end-side cutout31and the hole32, the one axial-direction end portion201easily expands. Thus, the first conductor40is easily pushed into the tubular body20, and the first conductor40is easily assembled to the tubular body20.

As illustrated inFIGS.8and9, the first protrusion41includes the flange412axially facing the one axial-direction end surface201A of the tubular body20. This can reduce excessive insertion of the first conductor40at the time of inserting the first conductor40into the tubular body20.

When the first conductor40is inserted into the tubular body20X illustrated inFIG.19, the first straight portion422having the outside diameter D2larger than the inside diameter D1of the tubular body20X acts to expand the one axial-direction end portion201of the tubular body20X. At this time, a portion of the one axial-direction end portion201near the end portion on the other axial-direction X2 side of the end-side cutout S20moves in the circumferential direction of the tubular body20X. The portion of the tubular body20X brought into contact with the first straight portion422moves radially outward of the tubular body20X. Thus, the one axial-direction end portion201of the tubular body20X is expanded. At this time, the axial center of the one axial-direction end portion201is shifted from the axial center of the one axial-direction end portion201having no first conductor40being inserted. As illustrated inFIG.20, when the first conductor40is inserted until the flange412comes into contact with the one axial-direction end surface201A, the displacement of the axial center near the one axial-direction end surface201A is large. Thus, the first conductor40is easily inclined from the direction along the axial center of the tubular body20X having no first conductor40being inserted. The first conductor40is inclined toward the end-side cutout S20.FIG.21illustrates a state in which the first conductor40is inclined at an angle θ.

On the other hand, in the contact terminal2according to the first embodiment, as illustrated inFIG.10, the first straight portion422is partially exposed from the hole32from one axial-direction end422A to the other axial-direction end422B along the axial direction. That is, the first straight portion422is partially exposed from the hole32. This allows the exposed portion of the first straight portion422not to be in contact with the tubular body20, thus reducing inclination of the first conductor40with respect to the tubular body20.

The second straight portion424has an outside diameter D3(FIG.6) substantially identical to the inside diameter D1of the tubular body20. This can reduce inclination of the first conductor40with respect to the tubular body20. As long as a relationship between the outside diameter D3and the inside diameter D1satisfies 0<D1−D3≤6 μm, the above effect can be obtained. For example, in a case where the tubular body20has an inside diameter D1of 47 μm and an outside diameter of 58 μm, provided that the second straight portion424has an outside diameter D3of 45 μm, the above effect can be obtained.

In addition, as illustrated inFIG.7, the one axial-direction end portion201includes a pair of circumferential protrusions201C and201D protruding in the circumferential direction so as to approach each other. The hole32includes circumferential protruding edges322and323that are edges of the circumferential protrusions201C and201D. The first conductor40is held by the circumferential protrusions201C and201D, thus reducing the inclination of the first conductor40(FIG.9).

As a modification of the present embodiment, as illustrated inFIG.11, the distance L1between the wall surface425and the flange412may be substantially equal to the distance L2between the hole32and the one axial-direction end surface201A. This can reduce the axial movement of the first conductor40with respect to the tubular body20. As long as a relationship between the distances L1and L2satisfies 0≤L1−L2≤30 μm, the above effect can be obtained.

As illustrated inFIG.8, the end-side cutout31includes a constant width portion311having a width Wz constant along the axial direction. The constant width portion311is elongated from the one axial-direction end surface201A to a position overlapping the inclined portion421as viewed in the first direction Y. This allows the first conductor40to be held by the portion near the constant width portion311in the tubular body20, and can reduce the inclination of the first conductor40.

FIGS.12to18are views each illustrating a second embodiment of a structure for fastening the first conductor40to the tubular body20. In the first conductor40and the tubular body20according to the second embodiment, components corresponding to those in the first embodiment are denoted by the same reference numerals as those in the first embodiment. Thus, the second embodiment can achieve the same operational effects as those based on the foregoing distinctive features of the first embodiment. Here, the shapes of the end-side cutout31and the hole32, which are differences from the first embodiment, will be described in detail with reference toFIGS.17and18.

As illustrated inFIG.17, the end-side cutout31includes a constant width portion31A and a wide portion31B. The constant width portion31A has a width Wz constant along the axial direction from the one axial-direction end surface201A. The wide portion31B is connected to the other axial-direction X2 side of the constant width portion31A, and has a width Wz gradually increased toward the other axial-direction X2 side.

That is, the end-side cutout31includes the wide portion31B having the width Wz gradually increased toward the other axial-direction X2 side. Largely cutting out the end-side cutout31allows the one axial-direction end portion201of the tubular body20to be more easily expanded. In addition, inclination of the first conductor40with respect to the tubular body20can be reduced.

As illustrated inFIG.18, the hole32includes a narrow-width portion32A having a circumferential width Wz gradually decreased toward the other axial-direction X2 side. This allows the shape of the hole32to conform to the shape of the inclined portion421.

A description will now be given of a fastening structure, according to the present embodiment, for fastening the second conductor50of the contact terminal2to the tubular body20.FIGS.22and23are views each illustrating an exploded state before the second conductor50is fastened to the tubular body20.FIG.22is a view as viewed from an end-side cutout202B side of the tubular body20.FIG.23is a view as viewed from a hole202C side of the tubular body20.

The other axial-direction end portion202of the tubular body20has the end-side cutout202B and the hole202C.

The end-side cutout202B is formed in a shape cut out along the axial direction from the other axial-direction end surface202A of the other axial-direction end portion202. The hole202C is open at the other axial-direction end portion202. The end-side cutout202B and the hole202C face each other in a direction (radial direction) perpendicular to the axial direction.

That is, the tubular body20has the end-side cutout202B provided in a shape cut out from the other axial-direction end surface202A toward the one axial-direction X1 side at the other axial-direction end portion202of the tubular body20, and the hole202C which is open at the other axial-direction end portion202.

The second conductor50includes the second protrusion51that protrudes from the tubular body20to the other axial-direction X2 side and the second insertion52that is connected to the one axial-direction X1 side of the second protrusion51and disposed inside the tubular body20. The second protrusion51includes a flange512on the one axial-direction X1 side.

The second insertion52includes an inclined portion521, a third straight portion522, a narrow portion523, and a fourth straight portion524. The inclined portion521has an outside diameter gradually increased toward the other axial-direction X2 side. The third straight portion522is connected to the other axial-direction X2 side of the inclined portion521, and has an outside diameter constant along the axial direction.

That is, the second insertion52includes the inclined portion521having the outside diameter gradually increased toward the other axial-direction X2 side, and the third straight portion522connected to the other axial-direction X2 side of the inclined portion521and having the outside diameter constant along the axial direction.

The outside diameter of the third straight portion522is larger than the inside diameter of the tubular body20.

The narrow portion523is connected to the other axial-direction X2 side of the third straight portion522and is connected to the one axial-direction X1 side of the flange512. The narrow portion523has an outside diameter smaller than that of the third straight portion522.

The fourth straight portion524is connected to the one axial-direction X1 side of the inclined portion521, and has an outside diameter constant along the axial direction.

When the second conductor50is assembled to the tubular body20, the fourth straight portion524is inserted into the tubular body20from the other axial-direction end surface202A. As the insertion proceeds, the inclined portion521comes into contact with an inner periphery of the other axial-direction end surface202A. As the second conductor50is pushed in as it is, the other axial-direction end portion202expands, and the third straight portion522is inserted into the tubular body20.

As the insertion further proceeds, the flange512comes into contact with the other axial-direction end surface202A, thus restricting the insertion of the second conductor50.FIG.24illustrates a state in which the second conductor50is pushed into the tubular body20and the flange512is in contact with the other axial-direction end surface202A inFIG.22.FIG.25illustrates a state in which the second conductor50is pushed into the tubular body20and the flange512is in contact with the other axial-direction end surface202A inFIG.23.

In the states illustrated inFIGS.24and25, the third straight portion522is pinched from both sides in the direction perpendicular to the axial direction by a pair of arms202D and202E of the tubular body20. The arms202D and202E are interposed between the end-side cutout202B and the hole202C.

Since the outside diameter of the third straight portion522is larger than the inside diameter of the tubular body20, the third straight portion522is pressed by the pair of arms202D and202E. That is, the third straight portion522is in contact with the arms202D and202E. This allows the second conductor50to be fastened to the tubular body20.

Since the tubular body20has the end-side cutout202B and the hole202C, the other axial-direction end portion202easily expands, the second conductor50is easily pushed into the tubular body20, and the second conductor50is easily assembled to the tubular body20.

A wall surface525is formed in the level-difference portion between the third straight portion522and the narrow portion523(FIG.22). Here, as illustrated inFIG.25, a distance between the wall surface525and the flange512is longer than a distance between the hole202C and the other axial-direction end surface202A. Consequently, in the state ofFIG.25, the narrow portion523is fitted between the hole202C and the other axial-direction end surface202A. Then, the wall surface525is contactable with the hole202C.

That is, the wall surface525disposed at the other axial-direction end of the third straight portion522is contactable with the hole202C. This allows the second conductor50assembled to the tubular body20to be less likely to come off from the tubular body20.

Thus, the fastening structure for fastening the second conductor50to the tubular body20can achieve the same effect based on the same configuration as the foregoing fastening structure for the first conductor40.

Since the fourth straight portion524is elongated in the axial direction so as to be inserted into the tubular body20and contactable with the first body21(FIG.3), the fourth straight portion524is long in axial length and increases the effect of reducing the inclination of the second conductor50with respect to the tubular body20.

Furthermore, the other axial-direction end portion202may have a configuration as illustrated inFIG.26. InFIG.26, in front view of the hole202C, the hole202C is formed to be line-symmetric with respect to the central axis of the tubular body20. The hole202C has a recess202C1on the one axial-direction X1 side and a protruding edge202C2on the other axial-direction X2 side. The recess202C1is recessed to the one axial-direction X1 side. The other axial-direction end portion202includes a protrusion202F protruding to the one axial-direction X1 side. The protruding edge202C2is an edge of the protrusion202F.

While the embodiments of the present disclosure have been described above, the embodiments can be modified in various ways within the scope of the present disclosure.

For example, the foregoing fastening structure for the conductor can also be applied to a contact terminal in which two sliding contact points are formed by conductors disposed on both sides in an axial direction and a body at an intermediate position of a tubular body into which the conductors are inserted. In addition, the fastening structure may be applied to a contact terminal configured by fastening only one conductor to a tubular body.

The present disclosure is applicable to electrical inspections of, for example, various inspection targets.

Features of the above-described embodiments and the modifications thereof may be combined appropriately as long as no conflict arises.