Metal mold for crimping and crimping device

A crimping die including a first die piece having a recess portion and a second die piece having a protrusion portion is provided. An inner wall surface of the recess portion has a bottom wall surface and recess-side lateral end surfaces. An outer surface of the protrusion portion has a top end surface and protrusion-side lateral end surfaces. The bottom wall surface has a recess-side projection portion, a recess-side concave portion, and a recess-side curvature changing portion. The top end surface has a protrusion-side projection portion, a protrusion-side concave portion, and a protrusion-side curvature changing portion. A sign of curvature of the bottom wall surface changes at a boundary portion in the recess-side curvature changing portion with respect to the recess-side concave portion. A sign of curvature of the top end surface changes at a boundary portion in the protrusion-side curvature changing portion with respect to the protrusion-side concave portion.

BACKGROUND OF THE INVENTION

The present invention relates to a crimping die, particularly to a crimping die used for crimping a tubular crimp portion of a terminal fitting onto a conductive wire lying in the crimp portion.

The present invention also relates to a crimping equipment having a crimping die.

The present invention also relates to a method of manufacturing a conductive wire with a terminal by means of a crimping die or a crimping equipment.

It is well known to manufacture a conductive wire with a terminal by inserting a conductive wire into a tubular crimp portion of a terminal fitting and crimping (i.e., swaging) the crimp portion onto the conductive wire by means of a crimping die. For such a crimp portion, a tubular crimp portion of so-called closed barrel type may be used. The crimp portion of this type is deformed under pressure (squashed) by means of a crimping die and thereby joined with a conductive wire lying in the crimp portion.

In terms of the outer shape (crimp shape) of a crimp portion after crimping, a dumbbell-like crimp shape (hereinafter also called “narrowed elliptical shape”) in cross section shown inFIG. 33leads to excellent crimp strength and excellent electric characteristics (e.g., a crimp resistance residual). A crimping die capable of forming the narrowed elliptical shape as the crimp shape has been developed to date, and one example thereof is a crimping die described in JP 5686064 B.

As shown inFIGS. 32 and 33, the crimping die (hereinafter called “conventional die100”) described in the above publication has a first die piece103and a second die piece105, the first die piece103being provided with a recess surface102for constraining a crimp portion101of circular tube shape formed in a terminal fitting, and the second die piece105being provided with a protrusion surface104serving as a counterpart of the recess surface102. This conventional die100sandwiches the crimp portion101between the recess surface102and the protrusion surface104to compress and deform the portion101, thereby crimping and fixing the crimp portion101onto a conductive wire106lying in the crimp portion101.

FIGS. 32 and 33show cross sections of the conventional die100(precisely, cross sections with the depth direction being defined as a normal line direction), whereFIG. 32shows the state immediately before crimping, andFIG. 33shows the state immediately after completion of the crimping.

As shown inFIG. 32, in the conventional die100above, a first projection portion107projects from the bottom portion of the recess surface102. This first projection portion107extends along the depth direction of the first die piece103. A second projection portion108projects from the top end portion of the protrusion surface104. This second projection portion108extends along the depth direction of the second die piece105. In the conventional die100, the lateral width of the bottom portion of the recess surface102and that of the top end portion of the protrusion surface104coincide with the outer diameter of the crimp portion101.

The conventional die100thus configured can compress and deform the crimp portion101into a narrowed elliptical shape. Further, at crimping, the conventional die100can squash the crimp portion101in a longitudinal direction (Z direction inFIG. 33) while keeping the lateral width of the crimp portion101unchanged.

As shown inFIGS. 32 and 33, however, in the conventional die100, the bottom portion of the recess surface102and the top end portion of the protrusion surface104are different in shape from each other, so that the cross-sectional shape of the crimp portion101formed through crimping should be affected by the shape difference between the bottom portion and the top end portion. More specifically, the bottom portion of the recess surface102has curved surfaces109extending separately from the lateral sides of the first projection portion107. Each curved surface109is curved in a concave form and smoothly connected to the corresponding lateral end portion of the recess surface102. On the other hand, the top end portion of the protrusion surface104has curved surfaces110extending separately from the lateral sides of the second projection portion108toward the lateral ends of the protrusion surface104. Each curved surface110is curved in a concave form and extends up to a position slightly anterior to the corresponding lateral end of the protrusion surface104. The top end portion of the protrusion surface104sharply bends at intermediate positions (specifically, one end position of each of the curved surfaces110) and forms flat surfaces111extending from the bending positions to the lateral ends of the protrusion surface104, separately.

Due to the shape difference as described above, the crimp portion101is unsuitably deformed in the longitudinal direction at crimping, as shown inFIG. 33. More specifically, since the curved surfaces109provided on the lateral sides of the first projection portion107in the bottom portion of the recess surface102separately extend up to the lateral end portions of the recess surface102, when the crimp portion101is pressed against the first projection portion107at crimping, the crimp portion101is deformed such that a material part of the crimp portion101is forced out from the contacting point toward the lateral sides (in the X direction inFIG. 33) along the curved surfaces109. Consequently, the crimp portion101is unsuitably deformed in the longitudinal direction, and in particular, the portion of the crimp portion101pressed with the first projection portion107is decreased in thickness, whereby cracks or fractures may be easily generated.

SUMMARY OF THE INVENTION

The present invention has been made in view of the above circumstances and is aimed at solving objects described below.

An object of the invention is to solve the above problem of the conventional art by providing a crimping die capable of appropriately deforming a crimp portion into a narrowed elliptical shape, thus achieving an excellent crimp.

Another object of the invention is to provide a crimping equipment having a crimping die achieving the above object.

Another object of the invention is to provide a method of manufacturing a conductive wire with a terminal using the crimping die and the crimping equipment.

In order to attain the foregoing objects, the present invention provides a crimping die for use in crimping a crimp portion of tubular shape included in a terminal fitting onto a conductive wire lying in the crimp portion, comprising: a first die piece having a recess portion and a second die piece having a protrusion portion that enters the recess portion, wherein an inner wall surface of the recess portion has a bottom wall surface and a pair of recess-side lateral end surfaces separately situated on opposite sides of the bottom wall surface, an outer surface of the protrusion portion has a top end surface and a pair of protrusion-side lateral end surfaces separately situated on opposite sides of the top end surface, the crimping die presses the crimp portion having the conductive wire therein with the inner wall surface and the outer surface to crimp the crimp portion onto the conductive wire, the bottom wall surface has a recess-side projection portion projecting toward an opening of the recess portion, a recess-side concave portion adjoining the recess-side projection portion, and a recess-side curvature changing portion between the recess-side concave portion and one of the pair of recess-side lateral end surfaces, the top end surface has a protrusion-side projection portion projecting in a same direction as a direction in which the protrusion portion protrudes, a protrusion-side concave portion adjoining the protrusion-side projection portion, and a protrusion-side curvature changing portion between the protrusion-side concave portion and one of the pair of protrusion-side lateral end surfaces, a sign of curvature of the bottom wall surface changes at a boundary portion in the recess-side curvature changing portion with respect to the recess-side concave portion, and a sign of curvature of the top end surface changes at a boundary portion in the protrusion-side curvature changing portion with respect to the protrusion-side concave portion.

The present invention provides another crimping die for use in crimping a crimp portion of tubular shape included in a terminal fitting onto a conductive wire lying in the crimp portion, comprising: a first die piece having a recess portion and a second die piece having a protrusion portion that enters the recess portion, wherein an inner wall surface of the recess portion has a bottom wall surface and a pair of recess-side lateral end surfaces separately situated on opposite sides of the bottom wall surface, an outer surface of the protrusion portion has a top end surface and a pair of protrusion-side lateral end surfaces separately situated on opposite sides of the top end surface, the crimping die presses the crimp portion having the conductive wire therein with the inner wall surface and the outer surface to crimp the crimp portion onto the conductive wire, the bottom wall surface has a recess-side projection portion projecting toward an opening of the recess portion, a recess-side concave portion adjoining the recess-side projection portion, and a recess-side curvature changing portion between the recess-side concave portion and one of the pair of recess-side lateral end surfaces, the top end surface has a protrusion-side projection portion projecting in a same direction as a direction in which the protrusion portion protrudes, a protrusion-side concave portion adjoining the protrusion-side projection portion, and a protrusion-side curvature changing portion between the protrusion-side concave portion and one of the pair of protrusion-side lateral end surfaces, the recess-side curvature changing portion forms a flat surface intersecting one of the pair of recess-side lateral end surfaces, and the protrusion-side curvature changing portion forms a flat surface intersecting one of the pair of protrusion-side lateral end surfaces.

The present invention also provides a crimping equipment for crimping the crimp portion onto the conductive wire by means of one of the crimping dies described above.

The present invention also provides a method of manufacturing a conductive wire with a terminal by crimping the crimp portion onto the conductive wire by means of one of the crimping dies according to the invention or the crimping equipment according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

A crimping die and a crimping equipment according to embodiments of the invention are described below with reference to the appended drawings. To clarify the positional relation and moving directions of members, three coordinate axes (X, Y and Z axes) intersecting one another are provided to the drawings referred to in the description below, as appropriate.

The embodiments described below are only examples used to facilitate the understanding of the invention, and the invention is by no means limited thereto. In other words, the invention may be modified or improved from the embodiments described below without departing from the scope and spirit of the invention. In particular, the materials, design dimensions and other factors of members used in the invention can be freely determined as long as the configuration of the invention is satisfied and the effects of the invention are produced. Needless to say, the invention includes its equivalents.

In the following description, the terms “same” and “coincide” include not only the completely same and coinciding cases but also the cases where things are different within an error range generally allowed in the technical field the invention pertains to. The same applies to the terms “symmetric” and “mirror image relationship” in the following description.

For describing a crimping die and a crimping equipment of the invention, the description is made on a conductive wire with a terminal that is manufactured using the crimping die and the crimping equipment of the invention with reference toFIGS. 1 to 3.FIG. 1is a perspective view showing a conductive wire with a terminal1(terminal-attached conductive wire1).FIG. 2is a cross-sectional view taken along line A-A inFIG. 1, showing a cross section of a crimp part7to be described later.FIG. 3is a cross-sectional view of the crimp part7that corresponds toFIG. 2but shows the state before crimping.

InFIG. 1, the direction in which a conductor cable2of the terminal-attached conductive wire1extends is defined as “Y direction,” and the side on which a terminal portion5of a terminal fitting4is present in the Y direction is defined as “+Y side,” while the opposite side thereof is defined as “−Y side.” InFIG. 2, in a cross section of the crimp part7having a narrowed elliptical shape, the direction corresponding to the major axis of the narrowed ellipse is defined as “X direction,” while the direction corresponding to the minor axis thereof (i.e., a narrowed direction) is defined as “Z direction.”

As shown inFIG. 1, the terminal-attached conductive wire1is composed of the conductor cable2and the terminal fitting4that is crimped on a plurality of conductive wires3bared at the tip of the conductor cable2. The conductive wires3are disposed in the form of strand wire inside the conductor cable2.

As shown inFIG. 1, the terminal fitting4has the terminal portion5of pin shape and a crimp portion6of circular tube shape (closed barrel type). The crimp portion6is disposed posterior to the terminal portion5(on the −Y side thereof), and the bared conductive wires3are disposed inside the crimp portion6.

A portion (hereinafter called “crimp part7”) slightly anterior to the rear end (−Y side end) of the crimp portion6(on the +Y side of the rear end) is pressed with the crimping die of the invention and thereby compressed and deformed. Thus, the crimp part7that had a circular tube shape as shown inFIG. 3before crimping is squashed into a narrowed elliptical shape as shown inFIG. 2, and consequently, the crimp portion6(precisely, the crimp part7) is crimped on and joined with the conductive wires3lying in the crimp portion6.

In this process, when the crimping die of the invention is used, the crimp part7after crimping has a substantially symmetric structure in the X direction and the Z direction as shown inFIG. 2. That is, the appearance when the terminal-attached conductive wire1is viewed from the +Z side and that when the terminal-attached conductive wire1is viewed from the −Z side are substantially the same. Owing to the crimping performed such that the crimp part7can have a symmetric structure as described above, the terminal-attached conductive wire1having excellent crimp strength and crimp resistance residual can be manufactured.

Configurations of Crimping Equipment and Crimping Die According to Embodiment 1 of the Invention

Next, the configurations of a crimping equipment (hereinafter called “crimping equipment10”) and a crimping die (hereinafter called “crimping die11”) according to Embodiment 1 of the invention are described with reference toFIGS. 4 to 14.FIG. 4is a perspective view showing the whole of the crimping equipment10.FIGS. 5 and 6are perspective views showing the crimping die11and the terminal-attached conductive wire1, whereFIG. 5shows the state before crimping, andFIG. 6shows the state at crimping.FIG. 7is a cross-sectional view taken along line B-B inFIG. 5.FIG. 8is a cross-sectional view taken along line B-B inFIG. 6. Note that inFIGS. 7 and 8, hatching is omitted from the cross sections of a first die piece12and a second die piece13for convenience of illustration.FIGS. 9 and 10are enlarged plan views of the crimping die11and a region therearound in the crimping equipment10, whereFIG. 9shows the state before crimping, andFIG. 10shows the state at crimping.FIGS. 11 and 12are enlarged perspective views of the crimping die11and a region therearound in the crimping equipment10, whereFIG. 11shows the state before crimping, andFIG. 12shows the state at crimping.FIGS. 13 and 14are side views of a part of the crimping equipment10as viewed from the arrow direction G-G inFIGS. 9 and 10, whereFIG. 13shows the state before crimping, andFIG. 14shows the state at crimping.

The crimping equipment10has the crimping die11as shown inFIG. 4and crimps the crimp portion6of the terminal fitting4onto the conductive wires3lying in the crimp portion6by means of the crimping die11. To be more specific, as shown inFIGS. 5 to 8, the crimping die11is composed of the first die piece12(so-called crimper) and the second die piece13(so-called anvil). As shown inFIGS. 5 and 7, the first die piece12has a recess portion14having a somewhat large depth. The second die piece13has a protrusion portion15having a substantially rectangular shape in a plan view and protruding toward the first die piece12. An inner wall surface16of the recess portion14corresponds in shape to an outer surface17of the protrusion portion15. More specifically, as shown inFIG. 7, a bottom wall surface18that is the innermost part of the inner wall surface16of the recess portion14substantially coincides in shape with a top end surface20that is the upper end part of the outer surface17of the protrusion portion15.

When the crimping equipment10is operated, the first die piece12linearly moves toward the second die piece13with the crimp portion6having the conductive wires3therein being placed between the recess portion14and the protrusion portion15. Consequently, as shown inFIGS. 6 and 8, the protrusion portion15enters the recess portion14, so that the crimp portion6(precisely, crimp part7) having the conductive wires3therein is sandwiched between the inner wall surface16of the recess portion14and the outer surface17of the protrusion portion15. This allows the bottom wall surface18and the top end surface20to together press the outer peripheral surface of the crimp part7, and the pressing force acts to compress and deform the crimp part7of circular shape into a narrowed elliptical shape. Thus, the crimp portion6is crimped on and joined with the conductive wires3lying in the crimp portion6.

The recess portion14and the protrusion portion15are described later in detail.

In the following description, the depth direction of the first die piece12and the second die piece13is defined as “Y direction,” and the direction in which the first die piece12moves “Z direction.” The X, Y and Z directions defined with respect to the crimping equipment10and the crimping die11are equivalent to the X, Y and Z directions provided for the terminal-attached conductive wire1shown inFIG. 1. In other words, the direction in which the conductive wires3inside the crimping portion6extend (that is, the Y direction) and the depth direction of the first die piece12and the second die piece13(that is, the Y direction) are the same as each other at crimping.

In the following description, the side on which the second die piece13is situated when viewed from the first die piece12side in the Z direction is defined as “+Z side,” and the side on which the first die piece12is situated when viewed from the second die piece13side is defined as “−Z side.”

Next, the whole structure of the crimping equipment10is described. As shown inFIGS. 4 and 9 to 12, the crimping equipment10has a base unit40, a power supply unit50, a piston unit60, a pressure amount adjusting unit70and a terminal fitting setting unit80around the crimping die11.

The base unit40is a device for supporting the crimping die11, the power supply unit50, the piston unit60and the pressure amount adjusting unit70. As shown inFIGS. 4 and 9 to 12, the base unit40has a pair of elongated blocks41arranged in parallel and a connecting block42interconnecting the pair of elongated blocks41. The pair of elongated blocks41are each a block body elongated in the Z direction. The connecting block42is joined with one ends (+Z side ends) in the longitudinal direction of the pair of elongated blocks41to connect the one ends to each other.

As shown inFIGS. 4 and 9, the crimping die11is sandwiched between the pair of elongated blocks41in the X direction. The power supply unit50and the piston unit60are attached to the other ends (−Z side ends) of the pair of elongated blocks41on the opposite side from the position of the connecting block42in the Z direction. The pressure amount adjusting unit70is assembled to the connecting block42on the +Z side of the connecting block42.

The power supply unit50is a device for supplying power to the piston unit60. As shown inFIG. 4, the power supply unit50has a power source cord51connected to a commercial power source (not shown) that is a source of power, a motor52driven by the power supplied from the commercial power source, and a gun type casing53. Although not shown inFIG. 4or other drawings, the casing53houses therein a power supply circuit connected to the power supply cord51, a substrate used for motor control, and a transmission mechanism for transmitting the rotating force of the motor52to the piston unit60.

A trigger53B to be operated by the user is attached to the casing53. Upon operation of the trigger53B, the motor52rotates, and the piston unit60is powered by the resulting rotational force and thereby operates. Consequently, the first die piece12moves to the4Z side toward the second die piece13.

While the power source of this embodiment is a commercial power source, the invention is not limited thereto, and a portable battery may be used as the power source.

As shown inFIG. 4, a cover54is attached to the fore end (+Z side end) of a cylindrical portion53A extending in the Z direction in the casing53. As shown inFIGS. 4, 13 and 14, a pair of fixing blocks55aligned in the X direction project from the cover54. Each fixing block55is of substantially C shape in a side view as shown inFIGS. 13 and 14and is pinned on the other end (−Z side end) in the longitudinal direction of the corresponding one of the pair of elongated blocks41of the base unit40while holding the other end. Thus, the power supply unit50is assembled to the base unit40.

The piston unit60is a device for moving the first die piece12to the +Z side toward the second die piece13by using the power supplied from the power supply unit50. As shown inFIG. 10, the piston unit60has a piston61movable forward and backward in the Z direction. The piston61is assembled to the power supply unit50(precisely, the power transmission mechanism of the power supply unit50). Upon operation of the trigger53B, the power supplied from the power supply unit50makes the piston61move toward the +Z side, i.e., to a pushing position. This movement (pushing movement) allows the first die piece12to move to the +Z side toward the second die piece13.

The amount of stroke of the piston61(i.e., the amount of movement of the first die piece12) is uniform. Therefore, every time the piston61arrives at the pushing position, the first die piece12is always placed at the same position in the Z direction.

As shown inFIG. 4, a retracting lever53C to be operated by the user is attached to the casing53of the power supply unit50. Upon operation of the retracting lever53C, a retracting mechanism (not shown) disposed in the casing53operates so that the piston61in the pushing position moves to the −Z side and retracts to the initial position. This movement (retracting movement) allows the first die piece12to move away from the second die piece13.

As shown inFIGS. 9 and 10, a piston-side aligning adopter62of stepped cylindrical shape is provided at the tip (+Z side end) of the piston61. The piston-side aligning adopter62is fitted in a slot hole (hereinafter called “first slot hole22”) formed at the rear end (−Z side end) of the first die piece12, as shown inFIGS. 9 and 10. When the piston-side aligning adopter62is fitted into the first slot hole22, the piston61and the first die piece12are joined to each other. Further, when the piston-side aligning adopter62is fitted into the first slot hole22, the position of the central axis of the piston61is adjusted to coincide (is aligned) in the X direction with the middle in the lateral width direction of the first die piece12.

The pressure amount adjusting unit70is a device for adjusting the amount of pressure applied to the crimp portion6at crimping, more specifically, the amount of deformation of the crimp portion6in the Z direction (that is, the thickness of the crimp part7after crimping). As shown inFIGS. 4 and 9 to 12, the pressure amount adjusting unit70has a movable rod71movable forward and rearward in the Z direction, a knob type handle72attached to the rear end (+Z side end) of the movable rod71, and a spacer73for pressure amount adjustment. The movable rod71is inserted in an insertion hole formed in the connecting block42of the base unit40. The movable rod71is constituted of a threaded rod whose outer peripheral surface has an external thread and engages an internal thread provided in the inner peripheral surface of the insertion hole.

The central axis of the movable rod71coincides with the central axis of the piston61in position in the X direction. As shown inFIGS. 9 and 10, a movable rod-side aligning adopter74of stepped cylindrical shape is provided at the tip (−Z side end) of the movable rod71. The movable rod-side aligning adopter74is fitted in a slot hole (hereinafter called “second slot hole23”) formed at the rear end (+Z side end) of the second die piece13, as shown inFIGS. 9 and 10. When the movable rod-side aligning adopter74is fitted into the second slot hole23, the movable rod71and the second die piece13are joined to each other. Further, since the movable rod-side aligning adopter74is fitted in the second slot hole23, the position of the central axis of the movable rod71coincides (is aligned) in the X direction with the middle in the lateral width direction of the second die piece13.

When the handle72is operated (specifically, rotated clockwise), the movable rod71moves toward the −Z side and arrives at the limit position at the end. The limit position is a position where the fore end (−Z side end surface) of the handle72abuts on the outer surface (the surface facing the handle72in the Z direction) of the connecting block42or the spacer73. Upon arrival of the movable rod71at the limit position, the second die piece13is set to a crimp performing position in the Z direction.

The crimp performing position of the second die piece13is adjustable by use of the spacer73. Specifically, the spacer73made of a flat plate material with a uniform thickness is detachably attached to the outer surface (the surface facing the handle72in the Z direction) of the connecting block42. The limit position of the movable rod71is changed by suitably replacing the spacer73(precisely, with another spacer73having a different thickness), and consequently, the crimp performing position of the second die piece13is adjusted in the Z direction. The change in the crimp performing position of the second die piece13results in the change in the amount of pressure applied to the crimp portion6at crimping, that is, the thickness of the crimp part7after crimping.

The terminal fitting setting unit80is a device for holding the terminal fitting4having the conductive wires3inside the crimp portion6, at crimping, between the first die piece12and the second die piece13in the Z direction. The terminal fitting setting unit80has a holding block81shown inFIGS. 13 and 14. The holding block81is disposed under the crimping die11(on the +Y side of the crimping die11) and, for example, fixed to the bottom surface (end surface on the +Y side) of the second die piece13by a screw or other means.

As shown inFIG. 9, the holding block81fixed to the bottom surface of the second die piece13somewhat protrudes beyond the fore end (−Z side end) of the second die piece13, and a long hole82is formed in the protruding portion. As shown inFIG. 9, the long hole82is exposed between the recess portion14of the first die piece12and the protrusion portion15of the second die piece13in the Z direction before crimping (i.e., when the first die piece12is separated from the second die piece13). In this state, the terminal portion5of the terminal fitting4having the conductive wires3inside the crimp portion6is inserted into the long hole82from the −Y side. Thus, the terminal fitting4is set between the first die piece12and the second die piece13in the Z direction. When the terminal fitting4is set between the first die piece12and the second die piece13, a certain part of the outer peripheral surface of the crimp portion6(precisely, the crimp part7) faces the bottom wall surface18of the recess portion14of the first die piece12, and the opposite part thereof faces the top end surface20of the protrusion portion15of the second die piece13.

Next, a crimping operation using the crimping die11is described as an example of the operation of the crimping equipment10having the configuration described above. For the crimping operation, the crimping die11, the power supply unit50, the piston unit60and the pressure amount adjusting unit70are mounted to specified locations of the base unit40. At this time, the first die piece12and the second die piece13composing the crimping die11are selected depending on the size of the terminal fitting4(precisely, the outer diameter of the crimp portion6) to be crimped, and the selected first and second die pieces12and13are placed between the pair of elongated blocks41. The holding block81of the terminal fitting setting unit80is fixed to the bottom surface (end surface on the +Y side) of the second die piece13. The spacer73having a thickness corresponding to a desired amount of pressure is attached to the outer surface (end surface on the +Z side) of the connecting block42.

Subsequently, the handle72of the pressure amount adjusting unit70is operated to make the movable rod71move toward the −Z side up to the limit position (i.e., the position where the fore end of the handle72abuts on the spacer73). Thus, the second die piece13is situated in the crimp performing position in the Z direction. In this stage, the recess portion14of the first die piece12and the protrusion portion15of the second die piece13are separated from each other in the Z direction, and the long hole82of the holding block81is exposed therebetween. In this state, the terminal fitting4having the conductive wires3inside the crimp portion6is held, and the terminal portion5of the terminal fitting4is inserted into the long hole82, whereby the terminal fitting4is set in a crimp position.

After the setting of the terminal fitting4is completed, upon operation of the trigger53B, the piston61is pushed toward the +Z side, so that the first die piece12is moved toward the second die piece13. Consequently, the protrusion portion15of the second die piece13enters the recess portion14of the first die piece12, the crimp portion6of the terminal fitting4is sandwiched between the bottom wall surface18of the recess portion14and the top end surface20of the protrusion portion15, and the crimp portion6is pressed by both the bottom wall surface18and the top end surface20. Thereafter, the retracting lever53C is operated to retract the piston61toward the −Z side so that the first die piece12is separated from the second die piece13, thereby releasing the pressure; then, the trigger53B is again operated to move the first die piece12toward the second die piece13to again sandwich the crimp portion6between the bottom wall surface18of the recess portion14and the top end surface20of the protrusion portion15.

As a result of repetitive pressing and releasing operation as above, the crimp portion6having a circular cross section (the crimp portion6shown inFIG. 3) is compressed and deformed to a narrowed elliptical shape in cross section, whereby the crimp portion6is crimped (swaged) onto the conductive wires3lying in the crimp portion6. After the crimping is completed, the fitting terminal4whose terminal portion5is inserted in the long hole82of the holding block81is pulled out toward the −Y side, so that the terminal fitting4is removed from the crimping die11. The crimping operation of the crimping equipment10finishes at this point, and the terminal-attached conductive wire1is completed.

Next, the recess portion14of the first die piece12and the protrusion portion15of the second die piece13are further described with reference toFIGS. 15 to 18in addition toFIGS. 5 and 6mentioned above.FIG. 15is a plan view of the recess portion14.FIG. 16is an enlarged view of a region designated by X inFIG. 15.FIG. 17is a plan view of the protrusion portion15.FIG. 18is an enlarged view of a region designated by X inFIG. 17.

In this embodiment, the recess portion14and the protrusion portion15are in the positions corresponding to each other and have the shapes corresponding to each other as shown inFIGS. 5 and 6. Specifically, the middle position of the recess portion14in the lateral width direction (X direction) coincides with the middle position of the protrusion portion15in the lateral width direction (X direction). The inner wall surface16of the recess portion14and the outer surface17of the protrusion portion15have similar shapes that are not exact but approximate inversions of each other in the Z direction.

The shape of the inner wall surface16of the recess portion14and that of the outer surface17of the protrusion portion15are described in detail below. In the following, described are the shapes thereof when the recess portion14and the protrusion portion15are viewed in the Y direction (more precisely, from the −Y side), i.e., in a plan view, unless otherwise noted. For convenience of description, the +X side with respect to the reference position (for instance, the position where a certain portion is formed) is also called “right side,” and the −X side with respect thereto is also called “left side.”

(Inner Wall Surface of Recess Portion)

First, the shape of the inner wall surface16of the recess portion14is described. As shown inFIG. 15, the inner wall surface16of the recess portion14has the bottom wall surface18and a pair of recess-side lateral end surfaces19situated on the opposite sides (+X side and −X side) of the bottom wall surface18. As shown inFIG. 15, the pair of recess-side lateral end surfaces19of the inner wall surface16are each inclined such that the distance between the recess-side lateral end surfaces19increases as advancing toward an opening24of the recess portion14. That is, the recess portion14of this embodiment is a tapered recess portion that decreases in width as advancing toward the innermost side (−Z side).

The lateral width (W11inFIG. 15) of the bottom wall surface18is smaller than the outer diameter (W10inFIG. 3) of the crimp portion6. Note that the outer diameter W10of the crimp portion6is the outer diameter of the crimp portion6, more precisely, the outer diameter of the crimp part7before crimping (i.e., before compression and deformation). The lateral width W11of the bottom wall surface18is the distance between the right end (end on the +X side) and the left end (end on the −X side) of the bottom wall surface18, and more specifically, the distance between the right end of a recess-side connecting portion29of a recess-side curvature changing portion27on the right side and the left end of a recess-side connecting portion29of a recess-side curvature changing portion27on the left side, of a right and left pair of recess-side curvature changing portions27to be described later.

In this embodiment, there is the position where, when the crimp portion6before crimping enters the recess portion14, the outer peripheral surface of the crimp portion6contacts both the pair of recess-side lateral end surfaces19, and the lateral width of the recess portion14on the deeper side (−Z side) than that position is smaller than the outer diameter W10of the crimp portion6.

Describing the shape of the bottom wall surface18, as shown inFIG. 15, the bottom wall surface18has a symmetric (laterally symmetric) shape with respect to the middle position of the bottom wall surface18in the lateral width direction (X direction) of the recess portion14. More specifically, one recess-side projection portion25is provided in a middle portion of the bottom wall surface18in the X direction. A right and left pair of recess-side concave portions26are provided on the opposite sides of the recess-side projection portion25and adjoin the portion25. The right and left pair of recess-side curvature changing portions27are provided at the opposite ends of the bottom wall surface18in the X direction.

The recess-side projection portion25projects on the +Z side toward the opening24of the recess portion14. The recess-side projection portion25is to abut on the outer peripheral surface of the crimp portion6and squashes a part of the outer peripheral surface (precisely, a part facing the recess-side projection portion25) toward the +Z side at crimping, thereby forming a narrowed shape at the part. In this embodiment, the recess-side projection portion25is curved in a mountain-like shape with a rounded top as shown inFIG. 15; however, the invention is not limited thereto, and the top of the recess-side projection portion25may be a flat surface parallel to an XY plane or a bending surface bent at an obtuse or acute angle.

As is clear fromFIG. 5, the recess-side projection portion25extends along the depth direction (Y direction) of the first die piece12. That is, in this embodiment, the recess-side projection portion25is to abut on the outer peripheral surface of the crimp portion6throughout the range that the recess-side projection portion25extends in the Y direction, at crimping.

The right and left pair of recess-side concave portions26separately adjoin the recess-side projection portion25and are each curved in a concave shape to form an arc. The radius of curvature of each recess-side concave portion26is substantially uniform over the entire recess-side concave portion26in the X direction. Each recess-side concave portion26extends along the depth direction (Y direction) of the first die piece12, as with the recess-side projection portion25.

As shown inFIG. 15, the right and left pair of recess-side curvature changing portions27are each situated between the corresponding recess-side concave portion26and the corresponding recess-side lateral end surface19in the X direction to adjoin both the portion26and the surface19. Each recess-side curvature changing portion27extends along the depth direction (Y direction) of the first die piece12, as with the recess-side projection portion25. Further, in this embodiment, the sign of curvature of the bottom wall surface18changes at a boundary portion in the recess-side curvature changing portion27with respect to the adjacent recess-side concave portion26.

With the bottom wall surface18in a plan view (i.e., viewed in the Y direction) being considered as a curve, the curvature of the bottom wall surface18herein refers to the curvature (degree of curving) in each portion of the curve. With the bottom wall surface18being considered as a curve, the sign of curvature of the bottom wall surface18is determined by the curving direction of an arc forming each portion of the curve. In this description, when advancing along the arc toward the +X side, the sign when the arc curves clockwise is defined as “+ (plus),” and the sign when the arc curves counterclockwise “− (minus).”

The recess-side curvature changing portion27is described in detail. As shown inFIG. 16, the recess-side curvature changing portion27is curved in a substantially S shape and has a recess-side curve portion28and the recess-side connecting portion29. The recess-side curve portion28is curved to have a convex shape in a position adjacent to the recess-side concave portion26in the X direction.

The recess-side connecting portion29interconnects the recess-side curve portion28and the recess-side lateral end surface19in the X direction. Of the recess-side connecting portion29, an end portion closer to the recess-side lateral end surface19in the X direction is curved in a concave shape.

As shown inFIG. 16, in each of the right and left pair of recess-side curvature changing portions27, the sign of curvature of the bottom wall surface18changes at the end position of the recess-side curve portion28on the side adjacent to the recess-side concave portion26(the position indicated by dashed line inFIG. 16, which is hereinafter called “recess-side changing position30”). In the configuration shown inFIG. 16, the sign F1of curvature is plus (+) in the recess-side concave portion26on the left side of the recess-side changing position30(the side closer to the middle of the bottom wall surface18), while the sign F2of curvature is minus (−) in the recess-side curve portion28on the right side of the recess-side changing position30(the side farther away from the middle of the bottom wall surface18).

In this embodiment, when the bottom wall surface18is seen in a plan view and considered as a curve, the recess-side changing position30corresponds to an inflection point of the curve, and the curvature at the recess-side changing position30is zero.

Further referring to the recess-side curvature changing portion27, in this embodiment, the top of the recess-side curve portion28of the recess-side curvature changing portion27coincides with the top of the recess-side projection portion25in position in the2direction, as shown inFIG. 15. In other words, in this embodiment, the top of the recess-side projection portion25coincides with the top of the recess-side curve portion28in position in the direction in which the portion25projects (Z direction).

Next, the shape of the outer surface17of the protrusion portion15is described. As shown inFIG. 17, the outer surface17of the protrusion portion15has the top end surface20and a pair of protrusion-side lateral end surfaces21situated on the opposite sides (+X side and −X side) of the top end surface20. The pair of protrusion-side lateral end surfaces21of the outer surface17are each inclined such that the distance between the protrusion-side lateral end surfaces21decreases as advancing toward the top of the protrusion portion15. That is, the protrusion portion15of this embodiment is a tapered protrusion portion that decreases in width as advancing toward the top (−Z side).

The lateral width (W12inFIG. 17) of the top end surface20is smaller than the outer diameter W10of the crimp portion6. As described above, the outer diameter W10of the crimp portion6is the outer diameter of the crimp portion6(more precisely, the crimp part7) before crimping. The lateral width W12of the top end surface20is the distance between the right end (end on the +X side) and the left end (end on the −X side) of the top end surface20, and more specifically, the distance between the right end of a protrusion-side connecting portion35of a protrusion-side curvature changing portion33on the right side and the left end of a protrusion-side connecting portion35of a protrusion-side curvature changing portion33on the left side, of a right and left pair of protrusion-side curvature changing portions33to be described later.

Describing the shape of the top end surface20, as shown inFIG. 17, the top end surface20has a symmetric (laterally symmetric) shape with respect to the middle position of the top end surface20in the lateral width direction (X direction) of the protrusion portion15. More specifically, one protrusion-side projection portion31is provided in a middle portion of the top end surface20in the X direction. A right and left pair of protrusion-side concave portions32are provided on the opposite sides of the protrusion-side projection portion31and adjoin the portion31. The right and left pair of protrusion-side curvature changing portions33are provided at the opposite ends of the top end surface20in the X direction.

The protrusion-side projection portion31projects in the same direction as the direction in which the protrusion portion15projects (i.e., on the −Z side). The protrusion-side projection portion31is to abut on the outer peripheral surface of the crimp portion6and squashes a certain part of the outer peripheral surface (precisely, a part facing the protrusion-side projection portion31) toward the −Z side at crimping, thereby forming a narrowed shape at the part. In this embodiment, the protrusion-side projection portion31is curved in a mountain-like shape with a rounded top as shown inFIG. 17; however, the invention is not limited thereto, and the top of the protrusion-side projection portion31may be a flat surface parallel to an XY plane or a bending surface bent at an obtuse or acute angle. In this embodiment, the amount of projection of the protrusion-side projection portion31(the amount of projection in the Z direction) is the same as that of the recess-side projection portion25but may be different therefrom.

As shown inFIG. 5, the protrusion-side projection portion31extends along the depth direction (Y direction) of the second die piece13. That is, in this embodiment, the protrusion-side projection portion31is to abut on the outer peripheral surface of the crimp portion6throughout the range that the protrusion-side projection portion31extends in the Y direction, at crimping.

The right and left pair of protrusion-side concave portions32separately adjoin the protrusion-side projection portion31and are each curved in a concave shape to form an arc. The radius of curvature of each protrusion-side concave portion32is substantially uniform over the entire protrusion-side concave portion32in the X direction. Each protrusion-side concave portion32extends along the depth direction (Y direction) of the second die piece13, as with the protrusion-side projection portion31.

As shown inFIG. 17, the right and left pair of protrusion-side curvature changing portions33are each situated between the corresponding protrusion-side concave portion32and the corresponding protrusion-side lateral end surface21in the X direction and adjoin both the portion32and the surface21. Each protrusion-side curvature changing portion33extends along the depth direction (Y direction) of the second die piece13, as with the protrusion-side projection portion31. Further, in this embodiment, the sign of curvature of the top end surface20changes at a boundary portion in the protrusion-side curvature changing portion33with respect to the adjacent protrusion-side concave portion32.

With the top end surface20in a plan view (i.e., viewed in the Y direction) being considered as a curve, the curvature of the top end surface20herein refers to the curvature in each portion of the curve. Since the sign of curvature of the top end surface20can be determined in the same manner as for the sign of curvature of the bottom wall surface18described above, the description therefore is omitted.

The protrusion-side curvature changing portion33is described in detail. As shown inFIG. 18, the protrusion-side curvature changing portion33is curved in a substantially V shape and has a protrusion-side curve portion34and the protrusion-side connecting portion35. The protrusion-side curve portion34is curved to have a convex shape in a position adjacent to the protrusion-side concave portion32in the X direction.

The protrusion-side connecting portion35interconnects the protrusion-side curve portion34and the protrusion-side lateral end surface21in the x direction and is a flat surface parallel to an XY plane or slightly inclined to an XY plane.

As shown inFIG. 18, in each of the right and left pair of protrusion-side curvature changing portions33, the sign of curvature of the top end surface20changes at the end position of the protrusion-side curve portion34on the side adjacent to the protrusion-side concave portion32(the position indicated by dashed line inFIG. 18, which is hereinafter called “protrusion-side changing position36”). In the configuration shown inFIG. 18, the sign F3of curvature is minus (−) in the protrusion-side concave portion32on the left side of the protrusion-side changing position36(the side closer to the middle of the top end surface20), while the sign F4of curvature is plus (+) in the protrusion-side curve portion34on the right side of the protrusion-side changing position36(the side farther away from the middle of the top end surface20).

In this embodiment, when the top end surface20is seen in a plan view and considered as a curve, the recess-side changing position30corresponds to an inflection point of the curve, and the curvature at the recess-side changing position30is zero.

Further referring to the protrusion-side curvature changing portion33, in this embodiment, the top of the protrusion-side curve portion34of the protrusion-side curvature changing portion33coincides with the top of the protrusion-side projection portion31in position in the Z direction, as shown inFIG. 17. In other words, in this embodiment, the top of the protrusion-side projection portion31coincides with the top of the protrusion-side curve portion34in position in the direction in which the portion31projects (Z direction).

Furthermore, in this embodiment, in the state where the bottom wall surface18of the recess portion14and the top end surface20of the protrusion portion15face each other (e.g., the state shown inFIG. 9), the recess-side projection portion25, the right and left pair of recess-side concave portions26and the right and left pair of recess-side curve portions28of the bottom wall surface18have the mirror image relationship with the protrusion-side projection portion31, the right and left pair of protrusion-side concave portions32and the right and left pair of protrusion-side curve portions34. The mirror image relationship herein refers to a symmetric relationship with respect to an imaginary XY plane (imaginary plane VS inFIG. 7) situated in the middle position in the Z direction between the bottom wall surface18and the top end surface20, precisely, between the top of the recess-side projection portion25and the top of the protrusion-side projection portion31.

In the foregoing, the description has been made on the shape of the bottom wall surface18of the recess portion14of the first die piece12and the shape of the top end surface20of the protrusion portion15of the second die piece13as characteristics of the crimping equipment10and the crimping die11according to this embodiment. Owing to those characteristics, the crimping equipment10and the crimping die11according to this embodiment can suitably compress and deform the crimp portion6of the terminal fitting4into a narrowed elliptical shape, thus the crimp portion6can be crimped well onto the conductive wires3lying in the crimp portion6.

Specifically, as described in “BACKGROUND OF THE INVENTION” above, in the crimping die (i.e., the conventional die100) illustrated in JP 5686064 B, the bottom portion of the recess surface102and the top end portion of the protrusion surface104are different in shape from each other as shown inFIGS. 32 and 33. Therefore, the crimp portion101after crimping should have a distorted shape in cross section in the Z direction. More specifically, the bottom portion of the recess surface102in the conventional die100has the curved surfaces109that are curved in a concave shape separately from the lateral sides of the first projection portion107and continuously extend up to the lateral end portions of the recess surface102. The expression “the curved surfaces109. . . continuously extend” herein means that the sign of curvature of the curved surfaces109does not change in any position.

On the other hand, while the top end portion of the protrusion surface104in the conventional die100has the curved surfaces110curved in a concave shape that extend separately from the lateral sides of the second projection portion108toward the lateral ends of the top end portion of the protrusion surface104, the top end portion of the protrusion surface104is bent at intermediate positions and forms the flat surfaces111extending from the bending portions to the lateral ends of the top end portion of the protrusion surface104.

As described above, in the conventional die100, the bottom portion of the recess surface102and the top end portion of the protrusion surface104are different in shape from each other. Accordingly, crimping using the conventional die100makes the crimp portion101unsuitably deformed in the longitudinal direction as shown inFIG. 33. More specifically, the crimp portion101is compressed and deformed through crimping such that on the side facing the protrusion surface104, the thickness of the portion101becomes uniform because of the above-described shape of the protrusion surface104. On the other hand, on the opposite side of the crimp portion101that faces the recess surface102, the crimp portion101is compressed and deformed such that a material part of the crimp portion101is forced out from the point pressed with the first projection portion107toward the lateral sides (in the X direction) along the above-described curved surfaces109. Consequently, the crimp portion101is unsuitably deformed in the Z direction, and in particular, the portion pressed with the first projection portion107is decreased in thickness, so that cracks or fractures may be easily generated there.

In contrast, in this embodiment, the recess-side curvature changing portion27is provided at each end of the bottom wall surface18of the recess portion14, and the sign of curvature changes at the boundary portion between the recess-side curvature changing portion27and the recess-side concave portion26. In other words, the curving direction of the bottom wall surface18of the recess portion14is switched at the boundary portion between the recess-side curvature changing portion27and the recess-side concave portion26. Similarly, the protrusion-side curvature changing portion33is provided at each end of the top end surface20of the protrusion portion15, and the sign of curvature changes at the boundary portion between the protrusion-side curvature changing portion33and the protrusion-side concave portion32. In other words, the curving direction of the top end surface20of the protrusion portion15is switched at the boundary portion between the protrusion-side curvature changing portion33and the protrusion-side concave portion32.

Owing to the foregoing configuration, in this embodiment, the recess-side curvature changing portions27can prevent a material part of the crimp portion6from being forced out from the point pressed with the recess-side projection portion25toward the lateral sides (in the X direction) along the recess-side concave portions26at crimping. Similarly, it is possible to prevent a material part of the crimp portion6from being forced out from the point pressed with the protrusion-side projection portion31toward the lateral sides (in the X direction) along the protrusion-side concave portions32. Thus, unsuitable deformation of the crimp portion6can be suppressed. In addition, this configuration makes it possible to prevent the crimp portion6from being locally decreased in thickness at the portion pressed with the recess-side projection portion25and the protrusion-side projection portion31, thus suppressing the generation of cracks or fractures at the pressed portion.

In this embodiment, the recess portion14is a tapered recess portion that decreases in width as advancing toward the innermost side (−Z side), and the lateral width of the bottom wall surface18of the recess portion14is smaller than the outer diameter of the crimp portion6. Further, in this embodiment, the protrusion portion15is a tapered protrusion portion that decreases in width as advancing toward the top (−Z side), and the lateral width of the top end surface20of the protrusion portion15is smaller than the outer diameter of the crimp portion6. This configuration makes it possible to more properly compress and deform the crimp portion6at crimping.

To be more specific, if the lateral width of the bottom wall surface18of the recess portion14and that of the top end surface20of the protrusion portion15each coincide with the outer diameter of the crimp portion6, when the crimp portion6is tried to be sufficiently crimped on the conductive wires3lying in the crimp portion6, the crimp portion6needs to be greatly compressed and deformed in the longitudinal direction (Z direction). In this case, the ratio of the lateral length to the longitudinal length of the crimp portion6(the ratio of the X directional length of the crimp portion6to the Z directional length thereof) after crimping is to be remarkably large, and a large difference arises in thickness between a compressed and deformed portion and an undeformed portion. Accordingly, fractures and the like are easily generated at the compressed and deformed portion having a smaller thickness.

In contrast, in this embodiment, the lateral width of the bottom wall surface18of the recess portion14and that of the top end surface20of the protrusion portion15are each smaller than the outer diameter of the crimp portion6, and this configuration can further reduce the amount of deformation of the crimp portion6in the longitudinal direction with respect to the amount of deformation thereof in the lateral direction in the process for crimping the crimp portion6onto the conductive wires3lying in the crimp portion6. Consequently, in this embodiment, the ratio of the lateral length to the longitudinal length of the crimp portion6after crimping can be made smaller, and this leads to a smaller difference in thickness between a compressed and deformed portion and an undeformed portion, thus suppressing the generation of fractures and the like at the compressed and deformed portion.

Meanwhile, when attention is paid to the crimp portion6crimped on the conductive wires3by means of the crimping die11according to this embodiment, as shown inFIGS. 19 to 22, it can be understood that the crimp portion6(precisely, the crimp part7) is properly compressed and deformed into a narrowed elliptical shape and takes on a substantially symmetric shape in the lateral direction (Z direction). Of the conductive wires3lying in the crimp portion6, some conductive wires3situated in the narrowed portion (i.e., the portion sandwiched between the recess-side projection portion25and the protrusion-side projection portion31at crimping) are squashed to such an extent that those conductive wires3are properly joined with the crimp portion6as shown inFIGS. 20 to 22.

FIG. 19is a view of the crimp portion6after crimping, as viewed from a lateral side.FIG. 20is a cross-sectional view taken along line C-C inFIG. 19.FIG. 21is a cross-sectional view of the crimp portion6and a region therearound shown inFIG. 19taken along line D-D inFIG. 20.FIG. 22is an image of the crimp portion6and the conductive wires3lying in the crimp portion6after crimping.

While, in this embodiment, the bottom wall surface18of the recess portion14has a symmetric (laterally symmetric) shape with respect to the middle of the bottom wall surface18in the X direction, the invention is not limited thereto, and the left half and the right half of the bottom wall surface18may have somewhat different shapes. Similarly, while, in this embodiment, the top end surface20of the protrusion portion15has a symmetric (laterally symmetric) shape with respect to the middle of the top end surface20in the X direction, the invention is not limited thereto, and the left half and the right half of the top end surface20may have somewhat different shapes. However, in terms of the quality of the terminal-attached conductive wire1, it is favorable that the bottom wall surface18and the top end surface20each have a laterally symmetric shape for achieving a good appearance of the crimp portion6after crimping.

In this embodiment, in the state where the bottom wall surface18of the recess portion14and the top end surface20of the protrusion portion15face each other, the recess-side projection portion25, the recess-side concave portions26and the recess-side curve portions28have the mirror image relationship with the protrusion-side projection portion31, the protrusion-side concave portions32and the protrusion-side curve portions34. However, the invention is not limited thereto, and the recess-side projection portion25may be somewhat different from the protrusion-side projection portion31, the recess-side concave portions26may be somewhat different from the protrusion-side concave portions32, and the recess-side curve portions28may be somewhat different from the protrusion-side curve portions34. However, when the recess-side projection portion25, the recess-side concave portions26and the recess-side curve portions28have the mirror image relationship with the protrusion-side projection portion31, the protrusion-side concave portions32and the protrusion-side curve portions34, it is possible to compress and deform the crimp portion6into a symmetric shape in the longitudinal direction, thus achieving a further excellent crimp connection. From this viewpoint, this embodiment is more favorable.

Configuration of Crimping Die According to Embodiment 2

In Embodiment 1, the sign of curvature of the top end surface20changes at the boundary portion in the protrusion-side curvature changing portion33with respect to the protrusion-side concave portion32. Further, in Embodiment 1, the boundary portion where the sign of curvature of the top end surface20changes is the end position of the protrusion-side curve portion34on the side adjacent to the protrusion-side concave portion32(that is, the protrusion-side changing position36). When the top end surface20is seen in a plan view and considered as a curve, the protrusion-side changing position36corresponds to an inflection point of the curve.

In regard to the above configuration, another embodiment (hereinafter called “Embodiment 2”) different from Embodiment 1 is also possible. A configuration according to Embodiment 2 is described with reference toFIGS. 23 and 24.FIG. 23is a plan view of a protrusion portion15of a second die piece13according to Embodiment 2, corresponding toFIG. 17.FIG. 24is an enlarged view of a region designated by X inFIG. 23, corresponding toFIG. 18. Note that inFIGS. 23 and 24, the same portions as those in Embodiment 1 are assigned the same reference numerals as those in Embodiment 1.

As shown inFIG. 23, in Embodiment 2, the top end surface20of the protrusion portion15has protrusion-side curvature changing portions33P at positions adjacent to the protrusion-side concave portions32. In Embodiment 2, the sign of curvature of the top end surface20changes at a boundary portion in the protrusion-side curvature changing portion33P with respect to the protrusion-side concave portion32as with Embodiment 1. Further, in Embodiment 2, as shown inFIG. 24, the boundary portion where the sign of curvature of the top end surface20changes forms a flat surface portion (the portion designated by S inFIG. 24). When the top end surface20is seen in a plan view and considered as a curve, the flat surface portion S is illustrated as a linear portion as shown inFIG. 24. Thus, when the top end surface20is seen in a plan view and considered as a curve, the portion where the sign of curvature of the top end surface20changes may be not a single point (inflection point) but a region (linear portion) having a certain width.

Although Embodiment 2 is different from Embodiment 1 in the above point, the remaining configuration is the same as Embodiment 1 and is therefore not further described.

Aside from that, in Embodiment 1, the sign of curvature of the bottom wall surface18changes at the boundary portion in the recess-side curvature changing portion27with respect to the recess-side concave portion26, and the boundary portion where the sign of curvature of the bottom wall surface18changes is the end position of the recess-side curve portion28on the side adjacent to the recess-side concave portion26(that is, the recess-side changing position30). When the bottom wall surface18is seen in a plan view and considered as a curve, the recess-side changing position30corresponds to a single point (inflection point) on the curve; however, the same way of thinking as above is applied here, and the portion where the sign of curvature of the bottom wall surface18changes may be a region (linear portion in a plan view) having a certain width.

Configuration of Crimping Die According to Embodiment 3

In Embodiment 1, the sign of curvature of the bottom wall surface18changes at the boundary portion in the recess-side curvature changing portion27with respect to the recess-side concave portion26. Further, in Embodiment 1, the sign of curvature of the top end surface20changes at the boundary portion in the protrusion-side curvature changing portion33with respect to the protrusion-side concave portion32. However, in regard to this configuration, another embodiment (hereinafter called “Embodiment 3”) different from Embodiment 1 is also possible.

A configuration according to Embodiment 3 is described with reference toFIGS. 25 and 26.FIG. 25is an enlarged plan view of a recess-side curvature changing portion27Q according to Embodiment 3, corresponding toFIG. 16.FIG. 26is an enlarged plan view of a protrusion-side curvature changing portion33Q according to Embodiment 3, corresponding toFIG. 18. Note that inFIGS. 25 and 26, the same portions as those in Embodiment 1 are assigned the same reference numerals as those in Embodiment 1.

The recess-side curvature changing portion27Q according to Embodiment 3 is not curved (i.e., the sign of curvature thereof cannot be defined), forms a flat surface intersecting the recess-side lateral end surface19, and in the configuration shown inFIG. 25, extends along an XY plane. Similarly, the protrusion-side curvature changing portion33Q is not curved (i.e., the sign of curvature thereof cannot be defined), forms a flat surface intersecting the protrusion-side lateral end surface21, and in the configuration shown inFIG. 26, extends along an XY plane.

Although Embodiment 3 is different from Embodiment 1 in the above point, the remaining configuration is the same as Embodiment 1 and is therefore not further described.

Even with the recess-side curvature changing portion27Q and the protrusion-side curvature changing portion33Q according to Embodiment 3 described above, it is possible to prevent a material part of the crimp portion6from being forced out from the point pressed with the recess-side projection portion25or the protrusion-side projection portion31toward the lateral sides (in the X direction) at crimping, thus suppressing unsuitable deformation of the crimp portion6.

Configuration of Crimping Die According to Embodiment 4

In Embodiment 1, the top of the recess-side curve portion28of the recess-side curvature changing portion27coincides with the top of the recess-side projection portion25in position in the Z direction (seeFIG. 15). Further, in Embodiment 1, the top of the protrusion-side curve portion34of the protrusion-side curvature changing portion33coincides with the top of the protrusion-side projection portion31in position in the Z direction (seeFIG. 17). However, in regard to this configuration, another embodiment (hereinafter called “Embodiment 4”) different from Embodiment 1 is also possible.

A configuration according to Embodiment 4 is described with reference toFIGS. 27 and 28.FIG. 27is a plan view of a crimping die11R according to a first example of Embodiment 4.FIG. 28is a plan view of a crimping die11S according to a second example of Embodiment 4. Note that inFIGS. 27 and 28, the same portions as those in Embodiment 1 are assigned the same reference numerals as those in Embodiment 1.

In Embodiment 4, as shown inFIGS. 27 and 28, the top of each recess-side curve portion28is different from the top of a recess-side projection portion25R in position in the Z direction. Similarly, in Embodiment 4, the top of each protrusion-side curve portion34is different from the top of a protrusion-side projection portion31R in position in the Z direction.

Specifically, as shown inFIG. 27, the recess-side projection portion25R may be higher than the recess-side curve portions28in the Z direction. That is, the recess-side projection portion25R may project beyond the tops of the recess-side curve portions28in its projecting direction; in other words, the top of the recess-side projection portion25R may be situated on the +Z side of the tops of the recess-side curve portions28. Further, as shown in the same drawing, the protrusion-side projection portion31R may be higher than the protrusion-side curve portions34in the Z direction. That is, the protrusion-side projection portion31R may project beyond the tops of the protrusion-side curve portions34in its projecting direction; in other words, the top of the protrusion-side projection portion31R may be situated on the −Z side of the tops of the protrusion-side curve portions34. The recess-side projection portion25R and the protrusion-side projection portion31R shown inFIG. 27each have flat surface portions (linear portions in a plan view) in their base portions.

Conversely, as shown inFIG. 28, a recess-side projection portion25S may be lower than the recess-side curve portions28in the Z direction. That is, the top of the recess-side projection portion25S may be situated on the −Z side of the tops of the recess-side curve portions28. Further, as shown in the same drawing, a protrusion-side projection portion31S may be lower than the protrusion-side curve portions34in the Z direction. That is, the top of the protrusion-side projection portion31S may be situated on the +Z side of the tops of the protrusion-side curve portions34.

As described above, the shape of the crimp portion6after crimping, more specifically, the depth of the narrowed portion can be adjusted by adjusting the positions of the tops of the recess-side projection portion25R,25S and the protrusion-side projection portion31R,31S.

Although Embodiment 4 is different from Embodiment 1 in the above point, the remaining configuration is the same as Embodiment 1 and is therefore not further described.

Configuration of Crimping Die According to Embodiment 5

In Embodiment 1, one recess-side projection portion25is provided in the middle portion of the bottom wall surface18of the recess portion14, and one protrusion-side projection portion31is provided in the middle portion of the top end surface20of the protrusion portion15. However, in regard to this configuration, another embodiment (hereinafter called “Embodiment 5”) different from Embodiment 1 is also possible.

A configuration according to Embodiment 5 is described with reference toFIGS. 29 to 31.FIG. 29is a plan view of a crimping die11T according to a first example of Embodiment 5.FIG. 30is a plan view of a crimping die11U according to a second example of Embodiment 5.FIG. 31is a plan view of a crimping die11V according to a third example of Embodiment 5. Note that inFIGS. 29 to 31, the same portions as those in Embodiment 1 are assigned the same reference numerals as those in Embodiment 1. For ease of understanding of the description, the crimp portion6immediately before crimping is illustrated by dashed line inFIGS. 29 to 31.

In Embodiment 5, as shown inFIGS. 29 to 31, a plurality of recess-side projection portions25T,25U,25V are provided in a middle portion of the bottom wall surface18of the recess portion14. Similarly, a plurality of protrusion-side projection portions31T,31U,31V are provided in a middle portion of the top end surface20of the protrusion portion15. This configuration makes it possible to increase crimped places (swaged places) in the crimp portion6, thereby crimping the crimp portion6onto the conductive wires3lying in the crimp portion6more firmly. At the same time, the die shape is more complicated than that in Embodiment 1, and this leads to increased work in the manufacture of the die.

The number of the recess-side projection portions25T,25U,25V and the number of the protrusion-side projection portions31T,31U,31V may be arbitrarily determined and are preferably the same as each other for the purpose of compressing and deforming the crimp portion6into a symmetric shape.

The tops of the recess-side projection portions25T may coincide in position in the Z direction, and the tops of the protrusion-side projection portions31T may coincide in position in the Z direction, as in the configuration shown inFIG. 29; however, the invention is not limited thereto, and the tops may be situated in different positions in the Z direction. For instance, as in the configuration shown inFIG. 30, among the recess-side projection portions25U, the top of the recess-side projection portion25U closer to the middle of the bottom wall surface18may be situated farther on the +Z side (i.e., may be higher). Similarly, among the protrusion-side projection portions31U, the top of the protrusion-side projection portion31U closer to the middle of the top end surface20may be situated farther on the −Z side (i.e., may be higher).

Conversely, as in the configuration shown inFIG. 31, among the recess-side projection portions25V, the top of the recess-side projection portion25V farther apart from the middle of the bottom wall surface18may be situated farther on the +Z side (i.e., may be higher). Similarly, among the protrusion-side projection portions31V, the top of the protrusion-side projection portion31V farther apart from the middle of the top end surface20may be situated farther on the −Z side (i.e., may be higher).

Although Embodiment 5 is different from Embodiment 1 in the above point, the remaining configuration is the same as Embodiment 1 and is therefore not further described.