JP2006014530A - Coil and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor coil and its manufacturing method that easily increase a space factor. <P>SOLUTION: The coil covers the one wound spirally edgewise on a long material 3 whose cross-section is flat. One end side of this long material 3 is wider but thinner than the other side and the cross-sectional area of the long material 3 is virtually constant over its longitudinal direction. This structure eliminates the stacked layers of the long material in the circumferential direction of a motor rotating shaft, and forms a single layer, which increases the space factor. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a coil and a manufacturing method thereof. In particular, the present invention relates to a motor coil that can realize a high space factor.

  In a conventional motor, a rotor or a stator having a coil provided on a core is widely known. In general, a rotor or a stator includes a ring portion and a plurality of protrusions extending in the radial direction of the ring portion. The coil is formed by winding a conductive wire around each of the protrusions to obtain the required number of ampere turns. In addition, a wire having a round or square cross section has been used for this conductive wire (for example, Non-Patent Document 1).

"Illustrations and illustrations All about small motors" by Naoshi Mijo and Tomoshi Sado Technical Review Company May 25, 2001 First edition published P91 Figure 3.29

  However, when such a conducting wire is used, a gap is generated between the conducting wires, and the space factor (the ratio of the conducting wire area in the cross section of the coil arrangement space) cannot be increased.

  Usually, the conductive wire is provided with an insulating coating such as enamel resin. However, this insulation coating prevents the heat generated when the motor is driven. If thin conductors are used, the number of conductors stacked in the circumferential direction of the ring (circumferential direction of the motor rotating shaft) will increase, resulting in an increase in the number of insulation coatings and lower heat dissipation efficiency. The increase in temperature caused a further decrease in efficiency.

  Accordingly, a main object of the present invention is to provide a motor coil and a manufacturing method thereof that can easily increase the space factor.

  Another object of the present invention is to provide a motor coil excellent in heat dissipation and a manufacturing method thereof.

  In the present invention, the above object is achieved by using a long material (conductive wire) having a flat cross section and devising the form and bending method of the long material.

  The coil of the present invention is a coil in which a long material having a flat cross section is spirally wound by edgewise winding. The long material has a larger width and a smaller thickness on the other end side than on one end side. And the cross-sectional area of a long material is characterized by being substantially constant over a longitudinal direction.

  This coil is configured to be edgewise wound using a flat plate-like long material. Edgewise winding is a winding method in which the thickness direction of the long material does not extend along the radial direction of the coil, but the width direction of the long material extends along the radial direction of the coil. With this configuration, it is possible to eliminate the lamination of long materials in the circumferential direction of the motor rotation shaft and to make a single layer, and to increase the space factor. In addition, if the lamination of the long material in the circumferential direction of the motor rotation shaft is eliminated to form a single layer, the insulation coating formed on the long material is not laminated, and a coil having a high heat dissipation effect can be obtained. it can.

  In addition, the width of the other end is larger and the thickness is smaller on the other end than the one end, but the cross-sectional area is substantially constant over the longitudinal direction. It is possible to obtain a coil that can be made uniform over the direction and has a shape corresponding to the slot shape of the core. Generally, the core of a motor includes a ring portion and a protrusion portion that extends in the radial direction of the ring portion and is wound with a long material. A slot formed between the protrusions and in which the long material is disposed is a slot. This slot is usually longer in the circumferential direction on the outer peripheral side of the ring portion than on the inner peripheral side. Therefore, by making the width of the long material arranged in the outer peripheral region of the core wider than the width of the long material arranged in the inner peripheral region, a coil suitable for the shape of the slot can be obtained. The space factor can be increased even when the circumferential distance is different between the inner and outer circumferences.

  On the other hand, the coil manufacturing method of the present invention comprises a step of preparing a long material having a flat cross section in which the width increases in the longitudinal direction and the thickness decreases but the cross-sectional area does not change, and the long material is continuously or conically with a conical roller. A step of intermittently rolling to form a bent portion, and forming a long material into a spiral coil.

  In this manufacturing method, a long material having a flat cross section in which the width increases in the longitudinal direction and the thickness decreases but the cross sectional area does not change is prepared in advance. The cross-sectional shape of a typical long material is a rectangle. As means for forming the long material, plastic working and machining with material removal can be used. Examples of the plastic working include rolling, a combination of rolling and pressing, and only pressing. Machining with material removal includes cutting and grinding.

  In the case of using rolling, a base material having a uniform cross-sectional shape in the longitudinal direction is prepared, and the base material may be rolled by sequentially increasing the rolling reduction.

  In the case of combining rolling and pressing, the rolling material may be pressed by sequentially changing the compression rate in the longitudinal direction of the obtained rolled material after rolling with the above-described reduction ratios sequentially increased.

  When only pressing is performed, a base material having a uniform cross-sectional shape in the longitudinal direction may be prepared, and the base material may be pressed by sequentially changing the compression rate in the longitudinal direction of the base material.

  When performing cutting or grinding, the base material is cut (grinded) using an appropriate cutting (grinding) tool, and a long material with a flat cross section whose width increases and decreases in thickness but does not change in cross-sectional area is obtained. What is necessary is just to form. When cutting (grinding), the shape of the base material is not particularly limited. Usually, a base material having a uniform cross-sectional shape in the longitudinal direction is used.

  In order to edgewise wind such a long material, a conical roller is used. When this long material is passed through the conical roller, one side edge side of the long material is crushed more than the other side edge side. Therefore, one side edge side of the long material is greatly extended in the longitudinal direction as compared with the other side edge side, and the long side edge side with a small degree of crushing is the inner circumference and the side edge side with a large degree of crushing is the outer circumference. The material will be bent.

  Therefore, if a long material is continuously rolled with a conical roller, a substantially cylindrical coil can be formed. In addition, when rolling with a conical roller is performed by intermittently closing the interval between the conical rollers for a predetermined time, the long material is bent to form a bent portion only while being rolled with the conical roller, and is not rolled. Since a straight portion is formed, a substantially elliptical cylindrical coil can be formed. The bending radius of the bent portion can be adjusted by changing the difference between the diameters of the one end side and the other end side of the conical roller to change the degree of crushing on one side edge side and the other side edge side of the long material.

  Here, the straight portion remains the cross-sectional shape of the long material, but the bent portion is greatly crushed on the outer peripheral side, so that the cross-sectional shape becomes trapezoidal. The bent portion of the trapezoidal cross section tends to have a smaller cross-sectional area than the cross section of the straight portion. Therefore, the electric resistance is relatively high, and the space factor is lowered, which is disadvantageous in terms of heat dissipation. Therefore, the bent portion is provided as short as possible on the end surface side of the ring portion (end surface side in the motor axial direction). With this configuration, the length of the portion with relatively high electrical resistance and large heat generation can be minimized, and large heat generation can be avoided, and the large heat generation portion can be disposed on the end surface side in the motor axial direction which is advantageous for heat dissipation.

  On the other hand, the linear part comprised by the elongate material of a rectangular cross section will be arrange | positioned in the space formed between each projection part of a core. For this reason, the linear portion is in contact with the protruding portion over a wide range, and efficient heat dissipation by heat conduction can be expected.

  Furthermore, as a modification of the manufacturing method of the present invention, a large number of coils can be manufactured efficiently. That is, another manufacturing method of the present invention includes the following steps.

A step of preparing a base material having a uniform cross-sectional shape in the longitudinal direction.
Rolling material in which the base material is rolled by alternately repeating ascending and descending changes in rolling reduction, and a narrow portion having a small width and a large thickness and a wide portion having a large width and a small thickness are alternately repeated in the longitudinal direction. Obtaining.
A step of rolling the rolled material continuously or intermittently with a conical roller to form a bent portion to obtain a formed body in which a plurality of spiral bodies are connected.
A step of obtaining a plurality of coils by cutting the narrow portion and the wide portion in the formed body.

  As described above, the width of the other end side is smaller than the one end side, and the thickness is smaller and the cross-sectional area is one coil if a substantially constant length material is wound edgewise along the longitudinal direction. Can be manufactured one by one. When obtaining this long material, if the base material is rolled by alternately repeating the ascending change and descending change in rolling reduction, a narrow part having a large width and a wide part having a large width and a small thickness are obtained. A rolled material that appears alternately in the longitudinal direction can be obtained. If this rolled material is edgewise wound using a conical roller, a molded body in which a plurality of coils are connected can be obtained. If such a molded body is obtained, a plurality of coils can be easily obtained by later cutting the narrow portion and the wide portion.

  As described above, according to the coil of the present invention, since the coil is adapted to the slot shape of the core constituting the motor, the space factor can be increased and the heat dissipation is excellent. In particular, since the cross-sectional area of the long material constituting the coil is constant over the longitudinal direction, the resistance of the long material can be made uniform over the entire length.

  Further, the coil manufacturing method of the present invention can easily form a coil suitable for the slot shape of the core.

  Embodiments of the present invention will be described below.

A method for producing the coil of the present invention by rolling will be described.
First, as shown in FIG. 1 (A), a base material made of a rod-shaped body having a square cross section is prepared. Here, a copper base material is prepared.

  Next, this base material 1 is rolled as shown in FIG. Rolling uses a total of two pairs of rollers, an upper and lower roller 2A that presses the base material 1 in the thickness direction and a left and right roller 2B that presses the base material 1 in the width direction. The upper and lower rollers 2A reduce the thickness of the base material 1, and the left and right rollers 2B control the width of the rolled material so that the width of the base material 1 is smoothly expanded.

  This rolling is performed in multiple stages, and as shown in FIG. 1 (C), a long material 3 having a large thickness and a small width on one end side but a small thickness and a large width on the other end side is formed. At this time, rolling is performed by sequentially changing the rolling reduction so that the cross-sectional area is constant over the longitudinal direction of the long material 3. By this rolling, a flat long material 3 having a rectangular cross section is formed. In FIG. 1 (C), the change in thickness and width in the longitudinal direction of the long material is exaggerated (the same applies to FIGS. 7C, 8C, and 9C described later), but the actual size of the long material is The thick side is 2mm thick and 2mm wide, and the thin side is 1mm thick and 4mm wide.

  Then, the obtained long material 3 is pressed and bent by a conical roller. FIG. 2 shows a state in which a long material is rolled by this conical roller. The conical rollers 4 sandwiching the long material 3 are arranged in parallel so that one end side in the axial direction of the roller 4 is a small diameter side and the other end side is a large diameter side. If a long material having a rectangular cross section is sandwiched between the conical rollers 4, the compression amount on the large diameter side is larger than the compression amount on the small diameter side, so the portion rolled on the large diameter side is the long material 3 The long material 3 is bent as a result. That is, the portion compressed on the large diameter side of the conical roller 3 is the outer peripheral side of the bend, and the portion compressed on the small diameter side of the roller is the inner peripheral side of the bend. Therefore, if rolling by the conical roller is continuously performed, the long material continues to bend as shown in FIG. 1 (D) and is sent out spirally from the conical roller 4 to form a coil.

  FIG. 3 shows a schematic shape of a coil obtained by rolling using such a conical roller. FIG. 3 is a schematic view in which the coil of the present invention is partially cut away. As shown in FIG. 3, the coil 10 is formed in a hollow frustum shape by winding a long material 3 edgewise in a spiral shape. That is, on the small diameter side of the coil 10, the long material 3 has a large thickness and a small width. On the contrary, on the large diameter side of the coil 10, the long material 3 has a large width and a small thickness. Further, the cross-sectional area of the long material 3 is substantially the same at any location in the longitudinal direction. Then, the obtained coil 10 may be provided with an insulating coating (not shown) such as enamel or ceramics.

  Such a coil 10 is incorporated into a core to form a stator. FIG. 4 is a schematic configuration diagram of a general motor. The inner rotor type motor shown in FIG. 4 includes a magnet that becomes the rotor 30 on the center side and a stator 40 on the outer periphery thereof. The stator 40 has a core including a ring portion 41 arranged coaxially with the rotor, and a plurality of protrusions 42 protruding from the ring portion 41 toward the center. Each protrusion 42 has a substantially T-shaped cross section when the motor is viewed from the axial direction, and a coil 10 is formed by winding a long material around the outer periphery thereof. Usually, an insulating material (not shown) is interposed between the coil 10 and the protrusion 42. In this motor, the rotational position of the magnet is detected using the Hall element 50 and fed back to the inverter 51 to control energization to the coil 10.

  FIG. 5 shows a partial plan view of the stator in which the coil of the present invention is used for the stator. In the coil 10, the long material on the inner peripheral side of the ring portion is narrow and thick, and the long material on the outer peripheral side is wide and thin. The space formed between the protrusions 42 is formed in a fan shape when viewed from the motor rotation axis direction. Therefore, if a narrow long material is arranged on the front end side (ring portion inner peripheral side) of the protruding portion 42 and a wide long material is arranged on the protruding portion base side (ring portion outer peripheral side), the fan-shaped The coil 10 can be stored in the space with a high space factor. Furthermore, since the cross-sectional area of the long material is substantially the same in the longitudinal direction, the electrical resistance is uniform in the longitudinal direction, and uniform heat generation can be achieved over the entire length.

  In order to fit the coil 10 of the present invention into the protrusion 42 of the stator, the protrusion 42 and the ring 41 may be prepared as separate parts. That is, the coil 10 may be fitted to the outer periphery of the protrusion 42 in a state removed from the ring portion 41, and the protrusion 42 may be fixed to the ring portion 41 in that state. If the ring part 41 and the projecting part 42 constituting the stator are configured as separate parts, the coil 10 can be easily incorporated into the core.

  In the present example, the case where the coil of the present invention is used for the stator has been described, but it can of course be used as a rotor. For example, it is a case where a plurality of protrusions protruding on the outer peripheral side of the ring portion are formed and a coil is fitted on the outside of the protrusion. In that case, the magnet which becomes a stator is arranged on the outer peripheral side of the protrusion.

  In Example 1, since the rolling with the conical roller was continuously performed, a coil having a circular shape with one turn of the coil was formed. However, when the rolling with the conical roller was intermittently performed, the shape of the one turn of the coil was elliptical. A coil can also be formed. That is, if rolling is performed intermittently with a conical roller, a portion rolled by the conical roller becomes a bent portion, and a portion not rolled by the roller becomes a straight portion. For this reason, one turn of the coil is formed in an elliptical shape with bent portions connected to both ends of the linear portion.

  FIG. 6 shows a state where one turn of the coil is mounted on the core. As shown in FIG. 6, the coil 10 is formed in a spiral shape by repeating a turn in which a bent portion 12 is continuously formed in an elliptical shape at both ends of the linear portion 11, and is fitted into the protruding portion 42 of the core. It is. In this case, only the bent portion 12 has a trapezoidal cross-sectional shape, and the cross-sectional area is smaller than that of the straight portion 12 where the cross-sectional shape remains rectangular. For this reason, the electric resistance of the bent portion 12 is larger than that of the straight portion 11, and heat is easily generated. However, the bent portion 12 is exposed at the end surface in the axial direction of the stator, thereby enabling efficient heat generation.

  In Example 1, a long material was obtained only by rolling, but in this example, a method of forming a long material by combining rolling and pressing will be described. FIG. 7 is an explanatory view of the method of the present invention, (A) is a perspective view of the base material, (B) is an explanatory view showing a state of rolling the base material, and (C) is a state of pressing the further rolled base material. Explanatory drawing shown, (D) is explanatory drawing which shows the state which rolls the obtained elongate material with a conical roller.

  Also in this example, as shown in FIGS. 7A and 7B, the same procedure as in Example 1 is performed until the base material 1 is prepared and the base material 1 is rolled. In this example, the rolled material is pressed with a punch 5 to form a long material 3 having a large thickness and a small width on one end side but a small thickness and a wide width on the other end side. At this time, pressing is performed by sequentially changing the compression ratio so that the cross-sectional area is constant over the longitudinal direction of the rolled material. By this pressing, a flat long material 3 having a rectangular cross section is formed.

  When such a long material 3 can be formed, it is rolled with a conical roller 4 and bent in a spiral shape in the same manner as in Example 1 to form a coil.

  In Example 3, a long material was obtained by a combination of rolling and pressing, but in this example, a method of forming a long material only by pressing will be described. FIG. 8 is an explanatory view of the method of the present invention, (A) is a perspective view of the base material, (B) is an explanatory view showing a state of pressing the base material, (C) is an explanation showing a state of further pressing the base material FIG. 4D is an explanatory view showing a state in which the obtained long material is rolled with a conical roller.

  Also in this example, as shown in FIG. 8A, the point that the base material is prepared is the same as in Examples 1 and 2. In this example, this base material is pressed with a punch 5. At that time, the press is performed by sequentially changing the compression ratio of the press. That is, pressing is performed so that the thickness of the long material 3 is successively reduced and the width is increased. However, the cross-sectional area of the long material 3 is the same in the longitudinal direction. By this pressing, a long material 3 having a large thickness and a small width on one end side, a small thickness and a large width on the other end side, and a constant cross-sectional area in the longitudinal direction is formed.

  When such a long material 3 can be formed, it is rolled with a conical roller 4 and bent in a spiral shape in the same manner as in Example 1 to form a coil.

  In Examples 1 to 5, a long material was obtained by plastic working such as rolling or pressing. In this example, a method of forming a long material by cutting will be described. FIG. 9 is an explanatory view of the method of the present invention, (A) is a perspective view of the base material, (B) is an explanatory view showing a state where the base material is cut, and (C) is an explanation showing a state where the base material is further cut. FIG. 4D is an explanatory view showing a state in which the obtained long material is rolled with a conical roller.

  Also in this example, as shown in FIG. 9A, the point that the base material is prepared is the same as in Examples 1 and 2. In this example, this base material is cut (FIGS. 9B and 9C). At that time, cutting is performed so that the width increases in the longitudinal direction of the base material 1 and the thickness decreases but the cross-sectional area does not change. By this cutting, the long material 3 having a large thickness and a small width on one end side, a small thickness and a large width on the other end side, and a constant cross-sectional area in the longitudinal direction is formed.

  When such a long material 3 can be formed, it is rolled with a conical roller 4 and bent in a spiral shape in the same manner as in Example 1 to form a coil.

  Next, in Examples 1-5, although the method of producing one coil from one elongate material was demonstrated, in this example, the method of producing several coils efficiently from one elongate material is demonstrated. To do.

  In this example as well, the base material is rolled while increasing the rolling reduction in the same manner as in Example 1. By this rolling, the rolling start side has a large thickness and a small width, but the rolling progress side can process the base material in a state where the thickness is small and the width is large. Next, the rolling is continuously performed while the rolling reduction is successively reduced. By this rolling, the base material is processed into a state in which the thickness is larger and the width is smaller toward the rolling progress side. In other words, if the ascending order change and descending order change of the rolling reduction are repeated alternately, as shown in FIG. 10, the narrow width portion 6A having a narrow width and a large thickness and the wide width portion 6B having a wide width and a small thickness are alternately elongated. A rolled material 6 that repeatedly appears in the direction can be obtained.

  If such a rolled material is rolled with a conical roller in the same manner as in Example 1, the rolled material 6 is spirally bent, and a formed body in which a plurality of coils are connected is formed. By cutting the narrow portion 6A and the wide portion 6B in this molded body, a large number of coils can be efficiently produced.

  As described above, according to the present invention, a motor with a high space factor and high heat dissipation efficiency can be configured. Therefore, the present invention is expected to be used for drive motors of electric vehicles and hybrid cars.

1A is a perspective view of a base material, FIG. 1B is an explanatory view showing a state of rolling the base material, FIG. 1C is an explanatory view showing a state of further rolling the base material, and FIG. It is explanatory drawing which shows the state which rolls a elongate material with a conical roller. FIG. 2 is an explanatory view showing a state in which the conical roller is rolled with a long material. FIG. 3 is a schematic view in which the coil of the present invention is partially cut away. FIG. 4 is a schematic configuration diagram of a general motor. FIG. 5 is a partial plan view of a stator using the coil of the present invention. It is a fragmentary perspective view which shows the state which mounted | wore with the coil whose 1 turn of an coil is elliptical. FIG. 7 is an explanatory view of the method of the present invention, (A) is a perspective view of the base material, (B) is an explanatory view showing a state of rolling the base material, and (C) is a state of pressing the further rolled base material. Explanatory drawing shown, (D) is explanatory drawing which shows the state which rolls the obtained elongate material with a conical roller. FIG. 8 is an explanatory view of the method of the present invention, (A) is a perspective view of the base material, (B) is an explanatory view showing a state of pressing the base material, (C) is an explanation showing a state of further pressing the base material FIG. 4D is an explanatory view showing a state in which the obtained long material is rolled with a conical roller. FIG. 9 is an explanatory view of the method of the present invention, (A) is a perspective view of the base material, (B) is an explanatory view showing a state where the base material is cut, and (C) is an explanation showing a state where the base material is further cut. FIG. 4D is an explanatory view showing a state in which the obtained long material is rolled with a conical roller. FIG. 10 is a plan view of a long material having a narrow portion and a wide portion.

Explanation of symbols

1 Base material 2A Vertical roller 2B Left and right roller 3 Long material 4 Conical roller
5 Punch 10 Coil 11 Linear part 12 Bent part 40 Stator
41 Ring part 42 Projection part 50 Hall element 51 Inverter

Claims (7)

A coil in which a long material having a flat cross section is spirally wound by edgewise winding,
The coil is characterized in that the long material has a larger width and a smaller thickness on the other end side than on one end side, and its cross-sectional area is substantially constant in the longitudinal direction. A step of preparing a long material having a flat cross section in which the width increases in the longitudinal direction and the thickness decreases but the cross-sectional area does not change; and
And a step of forming the bent portion by continuously or intermittently rolling the long material with a conical roller, and forming the long material into a spiral coil. The step of preparing the long material includes
Preparing a base material having a uniform cross-sectional shape in the longitudinal direction;
The method for manufacturing a coil according to claim 2, further comprising a step of rolling the base material by sequentially increasing a rolling reduction. The step of preparing the long material includes
Preparing a base material having a uniform cross-sectional shape in the longitudinal direction;
Rolling the base material by sequentially changing the rolling reduction; and
The method for manufacturing a coil according to claim 2, further comprising a step of pressing the rolled material by sequentially changing a compression ratio in a longitudinal direction of the obtained rolled material. The step of preparing the long material includes
Preparing a base material having a uniform cross-sectional shape in the longitudinal direction;
The method for manufacturing a coil according to claim 2, further comprising: pressing the base material by sequentially changing a compression rate in a longitudinal direction of the base material. The step of preparing the long material includes
Preparing the base material;
The method for manufacturing a coil according to claim 2, further comprising a step of machining the base material with removal of the base material. Preparing a base material having a uniform cross-sectional shape in the longitudinal direction;
Rolling material in which the base material is rolled by alternately repeating ascending and descending changes in rolling reduction, and a narrow portion having a small width and a large thickness and a wide portion having a large width and a small thickness are alternately repeated in the longitudinal direction. Obtaining
Rolling the rolled material continuously or intermittently with a conical roller to form a bent portion, and obtaining a molded body in which a plurality of spiral bodies are connected; and
And a step of cutting the narrow portion and the wide portion in the formed body to obtain a plurality of coils.

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