Patent Description:
A round metallic wire formed of a solid wire in a cross-section circular shape is used as conductors of various electric devices. The round metallic wire is inexpensive as compared with a square wire in a cross-section square shape, and excellent in strength against tension and bending, and further has such an advantage as easier bending in a desired direction than the square shape when attached to the electric device.

In focusing attention on such an advantage, for example, in <CIT>, the round metallic wire is used as a power line for supplying electric power to a three-phase rotary electric machine such as a motor. On the other hand, connecting three power lines to terminals individually brings about a problem such that flexibility of the power line causes a displacement at the time of fastening to the terminal, and <CIT> proposes that to prevent such a displacement, a power-line fixing member including three insertion holes through which the three power lines are inserted is used.

By using such a power-line fixing member, the displacement is securely suppressed, but due to the circular cross section of the power line, it rotates centered at an axial center in the insertion hole of the power-line fixing member. As a result, difficulty of positioning at the time of fastening with the terminal and a displacement due to vibrations have been unable to be completely eliminated.

In consideration of this point, <CIT> discloses a technique in which a jig crushes a predetermined portion of a power line to a cross-section non-circular shape and a resin member which is a power-line fixing member is molded integrally with this portion. Since the resin member is integrated with the cross-section non-circular portion, relative rotation between the power line and the resin member is suppressed.

However, in <CIT>, the cross-section non-circular portion is formed on the power line by the jig before the resin member as the power-line fixing member is integrated therewith. The round metallic wire made of copper or the like has flexibility, and hence can be bent to some extent to be fitted to a shape of an attachment portion when assembled to the motor or the like as described above, but actually, a power line formed in a three-dimensional shape, whose bending angle, length, and the like are specified beforehand to be fitted to the attachment portion, is used. The power line in <CIT> is also similar, and the predetermined portion of the three-dimensionally shaped power line processed to given design specifications is crushed by the jig through additional processing, and the resin member is integrated therewith.

Subjecting such a round metallic wire processed to/with the given design specifications and accuracy to the processing of partial crushing with the jig affects the bending angle, a bend position, and the like of the round metallic wire formed in the three-dimensional shape, and even though an aim to stop the rotation by using the resin member can be attained, there is a possibility that dimensional accuracy and accuracy of form of the round metallic wire itself are inferior against the design specifications.

The present invention was made in consideration of the above and has an object to provide a method for manufacturing a power distribution component including steps of processing a round metallic wire which make it possible to process a three-dimensionally shaped round metallic wire having a cross-section non-circular portion in a predetermined portion without performing additional processing, and having specified dimensional accuracy and accuracy of form.

To solve the above problems, a method for manufacturing a power distribution component for use in a predetermined position of an electric device is provided, the method includes the steps of processing a round metallic wire formed of a cross-section circular solid wire, for use as a conductor of the power distribution component, the method includes:.

Preferably, in the cross-section non-circular portion forming step, the cross-section non-circular portion is processed in a shape including a flat surface which comes into surface contact with an abutting surface of the wire holding portion of the bending machine.

Preferably, at either timing after the correction step and before the cross-section non-circular portion forming step or timing after the cross-section non-circular portion forming step, the round metallic wire is cut in a predetermined length.

According to the present invention, in an intermediate step in which the round metallic wire is processed in the predetermined three-dimensional shape, in at least one position, the cross-section non-circular portion having a non-circular cross-sectional shape is formed. At the time of bending, this cross-section non-circular portion is held by the wire holding portion of the bending machine, and the bending is performed in the predetermined three-dimensional shape. Holding the cross-section non-circular portion causes relative rotation centered at an axial center between the cross-section non-circular portion and the wire holding portion to be suppressed as compared with a case of the cross-section circular shape. In particular, processing this cross-section non-circular portion in a shape including the flat surface which comes into surface contact with the abutting surface of the wire holding portion of the bending machine causes the relative rotation between the cross-section non-circular portion and the wire holding portion to be further suppressed. As a result, bending accuracy in the three-dimensional shape is improved. Further, a displacement is eliminated in a holding position of the wire holding portion of the bending machine, which also reduces an error among processed products. Further, normally, after the bending, dimensional measurement is performed on the processed products by using an optical microscope or the like. At this time, the cross-section circular shape makes it difficult to focus on a tangent along a longitudinal direction, and makes positioning relative to a reference line of the optical microscope difficult, but having the cross-section non-circular portion, preferably having the flat surface makes a visible line clear, which makes it easy to focus on it and makes the positioning easy, resulting in improvement also in dimensional measurement accuracy.

Hence, according to the present invention, after obtaining the processed product of the three-dimensionally shaped round metallic wire having high dimensional accuracy and accuracy of form, the round metallic wire can be combined with the member such as a rotation stopper as it is while maintaining the high dimensional accuracy and the like without a need to perform additional processing for forming the cross-section non-circular portion. Further, the power distribution component integrated with the resin member by insert molding can also be manufactured easily by using the cross-section non-circular portion as it is without performing the additional processing.

An embodiment of the present invention will be hereinafter described using the drawings. <FIG> illustrates a processed product (hereinafter, to be referred to as "wire processed product") 100A of a round metallic wire <NUM> processed using a round metallic wire processing apparatus <NUM> (refer to <FIG>) The wire processed product 100A is used as, for example, a power line of a motor or the like as indicated in Patent Documents <NUM>, <NUM>, and formed in a three-dimensional shape to include connecting portions <NUM>, <NUM> to be connected to terminals or the like at both end portions, a plurality of bent portions <NUM>, <NUM>, and straight portions <NUM>, <NUM> between them. Then, in any portion of the wire processed product 100A, in a range of the straight portion <NUM> in the vicinity of the middle of the entire length, a cross-section non-circular portion <NUM> having a non-circular cross-sectional shape in a diameter direction (a direction orthogonal to a longitudinal direction (axial center direction) of the round metallic wire <NUM>) of the round metallic wire <NUM> is formed. A shape of the cross-section non-circular portion <NUM> is formed in a rectangle having four flat surfaces 105a to 105d on an outer peripheral surface as illustrated in <FIG>. Note that this shape of the cross-section non-circular portion <NUM> will be further described later.

The wire processed product 100A is set in a metal mold, and a resin member <NUM> is integrated by insert molding (refer to <FIG>). At this time, as illustrated in <FIG>, the resin member <NUM> is integrated closely around the cross-section non-circular portion <NUM>. The cross-section non-circular portion <NUM> has the four flat surfaces 105a to 105d, which eliminates the occurrence of relative rotation between them and the resin member <NUM> closely covering their peripheries. As a result, the wire processed product 100A of the round metallic wire <NUM> gets rid of being rotated and displaced in an axial direction at the time of fastening with the terminal of the motor or the like or by action of external vibrations, or the like. Note that as indicated in Patent Documents <NUM>, <NUM>, for example, in a case of being used for a three-phase motor or the like, it is naturally possible to have a structure in which the three wire processed products 100A of the round metallic wires <NUM> are subjected to insert molding together and covered with the common resin member <NUM> to thereby prevent a mutual displacement.

Next, a processing method and a processing apparatus for the round metallic wire <NUM> used as described above will be described. <FIG> schematically illustrates a schematic configuration of the round metallic wire processing apparatus <NUM>, and <FIG> and <FIG> each schematically illustrate each of processing machines for each processing step. As illustrated in these figures, the round metallic wire processing apparatus <NUM> includes a straightening machine <NUM>, a cross-section non-circular portion forming machine <NUM>, a bending machine <NUM>, and a cutting machine <NUM>.

The straightening machine <NUM> includes, for example, a plurality of straightening rollers <NUM> disposed to be opposed, as illustrated in <FIG> and <FIG>. The round metallic wire <NUM> targeted for processing is formed of a cross-section circular solid wire having a surface covered with enamel and made of metal such as copper, and provided as a coiled material wound in a coil shape. The straightening machine <NUM> is provided to correct its winding tendency caused by being wound in a coil shape. Here, in the wire processed product 100A illustrated in <FIG>, end portions serve as the connecting portions <NUM>, <NUM>, and a film of enamel is removed from these connecting portions <NUM>, <NUM>. The enamel film is removed after the straightening by, for example, shaving the surface, using chemicals, or the like.

A cross-section non-circular portion forming machine <NUM> forms a predetermined portion of the round metallic wire <NUM> processed linearly by the straightening machine <NUM> in a non-circular shape in the cross-sectional shape in the diameter direction of the round metallic wire <NUM>. A concrete structure of the cross-section non-circular portion forming machine <NUM> is not limited, but for example, is constituted of a pressing machine having pressing portions <NUM> which sandwiches the round metallic wire <NUM> on both sides along the diameter direction as illustrated in <FIG> and <FIG>. A facing surface 21a facing the round metallic wire <NUM> on the pressing portion <NUM> has a shape roughly fitted to an abutting surface 31a of a wire holding portion <NUM> of the bending machine <NUM> which separates from and approaches the round metallic wire <NUM> (refer to <FIG>). Concretely, for example, the wire holding portion <NUM> has at least the two abutting surfaces 31a on the round metallic wire <NUM>, and at least one surface of them is formed of a flat surface, and hence at least one of the pressing surfaces 21a of the pressing portions <NUM> is also formed in a flat surface.

In this example, both the facing surfaces 21a, 21a of the pressing portions <NUM>, <NUM> on both <NUM>-degree opposed sides of the cross-section non-circular portion forming machine <NUM> are formed as the flat surfaces. Accordingly, when these pressing portions <NUM>, <NUM> approach each other, one pair of the opposing flat surfaces 105a, 105c serving as the cross-section non-circular portion <NUM> are formed, and next, by turning the round metallic wire <NUM> by <NUM> degrees centered at an axial center and making the pressing portions <NUM>, <NUM> approach each other again, the other pair of the opposing flat surfaces 105b, 105d are formed, and the cross-section non-circular portion <NUM> having a substantially rectangular cross section in the diameter direction is formed.

However, the cross-sectional shape of the cross-section non-circular portion <NUM> is applicable unless circular, and for example, the flat surface may be formed only on one surface, or the flat surfaces may be formed only on two opposing surfaces. They may be formed on three or five surfaces or more. However, the closer the cross-sectional shape is to a circle, the more likely relative rotation between the cross-section non-circular portion <NUM> and the wire holding portion <NUM> of the bending machine <NUM> and the relative rotation, when the resin member <NUM> illustrated in <FIG> is molded integrally, between the two are to occur, and hence the flat surfaces are preferably set to eight surfaces or less. In addition to this, a modified cross section partially having any depression or projection such as a cross-section square or triangle is also applicable. In any case, these surfaces may each be in a shape having at least one flat surface capable of surface contact with the abutting surface 31a of the wire holding portion <NUM> of the bending machine <NUM>. Having at least one flat surface causes the abutting surface 31a of the wire holding portion <NUM> of the bending machine <NUM> to come into surface contact therewith, and thereby the round metallic wire <NUM> can be prevented from rotating centered at the axial center at the time of bending.

As the bending machine <NUM>, for example, the one provided with the wire holding portion (chuck) <NUM> at a tip of a three-dimensionally movable robot arm <NUM> as illustrated in <FIG>, the one having the wire holding portion <NUM> provided with a pair of opposing plates capable of separating from and approaching each other (corresponding to a portion in which work in a press die is held) as illustrated in <FIG>, or the like can be used. In each of these wire holding portions <NUM>, at least one surface (the two opposing surfaces in this embodiment) on which the round metallic wire <NUM> is held is set as the flat surface. Accordingly, as long as the round metallic wire <NUM> on which the flat surfaces 105a to 105d are formed by the cross-section non-circular portion forming machine <NUM> is set in each of these wire holding portions <NUM>, the round metallic wire <NUM> does not rotate centered at the axial center despite having a cross-section circular shape in portions expect the cross-section non-circular portion <NUM>.

In <FIG>, the bending machine <NUM> has the wire holding portion (chuck) <NUM> and a working portion (not illustrated) which comes into contact with the round metallic wire <NUM>, and either or both of these move three-dimensionally, and thereby the round metallic wire <NUM> is bent at a predetermined angle in a predetermined direction, or the like, and the round metallic wire <NUM> is processed in a predetermined three-dimensional shape to design specifications. In <FIG>, for example, the round metallic wire <NUM> is held between a pair of the abutting surfaces 31a, 31a of the wire holding portion <NUM> formed of the two plates, and a portion protruding from the wire holding portion <NUM> is approached from any direction by and brought into contact with a processing tool <NUM> (refer to "bending step" in <FIG> and <FIG>) to be thereby processed in a predetermined shape. Then, by varying the directions of the round metallic wire <NUM> or using the one capable of approaching it from different directions as the processing tool, the three-dimensional shape is imparted. Note that a concrete structure of the bending machine <NUM> is not limited at all as long as the round metallic wire <NUM> can be subjected to bending.

The cutting machine <NUM> cuts the round metallic wire <NUM> in a predetermined length in accordance with the design specifications. As long as the round metallic wire <NUM> can be cut, its structure is not limited at all. In this example, a cutting machine control unit <NUM> which automatically operates the cutting machine <NUM> is included (refer to <FIG>). The cutting machine control unit <NUM> controls the cutting machine <NUM> so as to perform cutting operation in the predetermined length in accordance with the beforehand set design specifications. The cutting machine control unit <NUM> only needs to control a cutting length, and moreover, timing of operating the cutting machine <NUM> can also be automatically controlled. Specifically, the round metallic wire <NUM> is straightened by the above-described straightening machine <NUM>, and thereafter at either timing before being transferred to the cross-section non-circular portion forming machine <NUM> (the state in <FIG>) or timing before being transferred to the bending machine <NUM> after the formation of the cross-section non-circular portion <NUM> (the state in <FIG>), the cutting machine <NUM> is operated to cut the round metallic wire <NUM> in the predetermined length.

The timing of cutting by using the cutting machine <NUM> can be optionally set depending on the kind of the three-dimensional shape to be imparted to the round metallic wire <NUM>, the required dimensional accuracy, and the like. As illustrated in <FIG>, cutting after the straightening makes, even when the cross-section non-circular portion <NUM> is formed in any position of end portions and a middle portion, its positioning easy, and also makes handling of the bending thereafter easy. Further, cutting after the bending sometimes also causes deformation due to a shock at the time of cutting, but the prior cutting eliminates such a possibility as described above.

As illustrated in <FIG>, cutting before the bending after the formation of the cross-section non-circular portion <NUM> makes it easy to perform the bending, but makes the positioning of the formation position of the cross-section non-circular portion <NUM> more difficult than that in cutting prior thereto since the cross-section non-circular portion <NUM> is formed while keeping the round metallic wire <NUM> long. On one hand, by forming the cross-section non-circular portion <NUM>, a size in a long direction is sometimes somewhat affected by a deformation in the diameter direction. Further, the cutting after the bending sometimes causes the deformation as described above. Thus, when the dimensional accuracy is required more strictly, or the like, the round metallic wire <NUM> is also considered to be kept long until the formation of the cross-section non-circular portion <NUM> and cut before the bending.

Next, one example of a method for processing the round metallic wire <NUM> will be described based on <FIG> and <FIG>. In the processing method, as described above, the material provided in a coil shape is transferred to the straightening machine <NUM> of the round metallic wire processing apparatus <NUM> to be linearly corrected (S1 in <FIG>). Thereafter, in accordance with specifications of the wire processed product 100A, an enamel cover is peeled for each predetermined distance so that the connecting ends <NUM>, <NUM> to the terminals or the like at attachment positions are formed.

Next, for example, the linearly corrected round metallic wire <NUM> is cut in a predetermined length by the cutting machine <NUM> (S2 in <FIG>). The advantage such that cutting at this time makes handling of later processing easy is as described above. Subsequently, the round metallic wire <NUM> cut in the predetermined length is transferred to the cross-section non-circular portion forming machine <NUM> to form the cross-section non-circular portion <NUM> (S3 in <FIG>). The cross-section non-circular portion <NUM> is formed in at least one position. The cross-section non-circular portion <NUM> is provided to prevent movement in a rotation direction when held by the wire holding portion <NUM> in the bending machine <NUM>, and in varying the portion held by the wire holding portion <NUM>, using a plurality of the bending machines <NUM>, or the like, corresponding thereto, the cross-section non-circular portions <NUM> can be formed in a plurality of positions.

Next, the cross-section non-circular portion <NUM> is held by the wire holding portion <NUM> of the bending machine <NUM>, and a three-dimensional shape in accordance with the design specifications is imparted (S4 in <FIG>). At this time, when the plurality of bending machines <NUM> are used, it is possible to in the initial bending machine <NUM>, hold the cross-section non-circular portion <NUM> in a certain predetermined position in the wire holding portion <NUM> and perform the bending, and thereafter in the next bending machine <NUM>, hold the cross-section non-circular portion <NUM> formed in a different position therefrom in the wire holding portion <NUM> and perform the bending, for example.

This completes the wire processed product 100A. Note that the timing of the cutting step is thus not limited to before the formation of the cross-section non-circular portion after the correction, but as illustrated in <FIG>, is also applicable to after the formation of the cross-section non-circular portion as described above. <FIG> is a flowchart illustrating one example of processing steps in that case, and after the correction step (S5 in <FIG>), the cross-section non-circular portion is formed (S6 in <FIG>), cutting is thereafter performed (S7 in <FIG>), and the bending step is performed (S8 in <FIG>) to obtain the wire processed product 100A.

According to this example, with respect to the round metallic wire <NUM>, the cross-section non-circular portion <NUM> is formed before the bending. Therefore, by holding the cross-section non-circular portion <NUM> in the wire holding portion <NUM>, the bending can be performed, which allows the prevention of the movement in the rotation direction centered at the axial center at the time of bending, or the like, resulting in enabling an increase of bending accuracy. Further, making a holding position of the wire holding portion <NUM> stable reduces variations in processing accuracy among products. Further, the round metallic wire <NUM> is transferred between the machines by feed rollers (not illustrated), and after the formation of the cross-section non-circular portion <NUM>, a slide with respect to the feed rollers is suppressed, which also enables suppression of a deterioration of the processing accuracy caused by variations in feed rate.

Further, when dimensions of the processed wire processed product 100A are measured using an optical microscope, a visible outline of the cross-section non-circular portion <NUM>, in particular, a surface processed in the flat surface is easy to observe. That is, in a circular cross section, it is difficult to focus on a tangent of the circular cross section when it is observed by the optical microscope, which sometimes affects dimensional measurement accuracy, but according to this example, it becomes easy to focus on the visible outline of the flat surface or the like, which increases the dimensional measurement accuracy.

Next, the wire processed product 100A of this example is used as a power distribution component, wherein it is integrated with the resin member <NUM> which functions as a rotation stopper for an attachment portion, or the like, the resin member <NUM> is integrated with the cross-section non-circular portion <NUM> by the insert molding (S10) to obtain a power distribution component <NUM> (refer to <FIG>), as illustrated in <FIG>. The obtained power distribution component <NUM> does not rotate mutually since the resin member <NUM> is integrated with the cross-section non-circular portion <NUM>. According to the present invention, the cross-section non-circular portion is not required to be formed by additional processing after completing the wire processed product as conventionally formed, and it is possible to prevent an influence on dimensional accuracy and a deformation accompanying the additional processing.

Claim 1:
A method for manufacturing a power distribution component (<NUM>) for use in a predetermined position of an electric device, the method including steps of processing a round metallic wire (<NUM>) formed of a cross-section circular solid wire, for use as a conductor of the power distribution component (<NUM>), the method comprising:
a correction step of linearly correcting a coiled material of the round metallic wire (<NUM>);
a cross-section non-circular portion forming step of forming a cross-section non-circular portion (<NUM>) having a non-circular cross-sectional shape in a diameter direction in at least one position of the round metallic wire (<NUM>) linearly corrected by the correction step;
a bending step of holding the cross-section non-circular portion (<NUM>) in a wire holding portion (<NUM>) of a bending machine (<NUM>) and performing bending in a predetermined three-dimensional shape; and
the step of integrally attaching a resin member (<NUM>) on an outer periphery of the cross-section non-circular portion (<NUM>) of the processed product of the round metallic wire (<NUM>).