JP5321789B2 - Method and apparatus for forming valley of serpentine annular coil and die used for forming the same - Google Patents

Description

  The present invention relates to a technique for manufacturing a meandering annular coil used as a stator winding of an electric motor (motor).

  As a motor for a hybrid vehicle or a motor for an electric vehicle, a permanent magnet type AC synchronous motor or a brushless DC motor using a permanent magnet as a rotor is often used. This type of motor includes a stator in which a winding coil is wound around a stator core for each of three phases including a U phase, a V phase, and a W phase, and a rotor composed of permanent magnets is driven by this stator in a three-phase manner. There is a permanent magnet type three-phase synchronous motor. The present applicant has a motor in which three-phase stator rings and two-phase annular winding coils are alternately arranged so as to be sequentially stacked along the axial direction, and a plurality of meander portions are formed in each annular coil. The stator was proposed first. (See Patent Document 1).

  Since this stator is not generally well known, its configuration will be described with reference to FIG. In the drawing, A is a perspective view of the assembled stator 30, and B is an exploded perspective view of the stator 30 to which the meandering annular winding is mounted. As shown in FIG. 6B, the stator 30 includes a U-phase stator ring (teeth ring) 31, a V-phase stator ring (teeth ring) 32, a W-phase stator ring (teeth ring) 33, a U-phase meandering annular coil 3, , W-phase meandering annular coil 4. The U-phase stator ring 31 includes a plurality (10 in the illustrated example) of U-phase teeth 34 (U-phase claw balls) 34 spaced apart at equal intervals in the circumferential direction, and a plurality of U-phase stator rings 31 spaced apart in the circumferential direction. A coupling portion 37 is provided. Each U-phase tooth 34 protrudes on one side in the axial direction (right side in the figure). The V-phase stator ring 32 has a plurality (10 in the illustrated example) of V-phase teeth 35 spaced apart at equal intervals in the circumferential direction, and a plurality of coupling portions 38 spaced apart in the circumferential direction. . Each V-phase tooth 35 protrudes on both sides in the axial direction. The W-phase stator ring 33 has a plurality (ten in this embodiment) of W-phase teeth 36 that are spaced apart at equal intervals in the circumferential direction, and a plurality of coupling portions 39 that are spaced apart in the circumferential direction. Each W-phase tooth 36 projects to the other side in the axial direction (left side in the figure). That is, the U-phase teeth 34 and the W-phase teeth 36 protrude in a direction approaching each other.

  The U-phase teeth 34, the V-phase teeth 35, and the W-phase teeth 36 overlap each other when the U-phase stator ring 31, the V-phase stator ring 32, and the W-phase stator ring 33 are laminated and joined at the respective connecting portions 37, 38, and 39. It is arranged at a relatively shifted position so as not to become. The U-phase annular coil 3 is formed by winding a conducting wire in an annular shape, and has a plurality of meandering portions 40 meandering in the axial direction of the stator 30. Similarly, the W-phase annular coil 4 also has a plurality of meandering portions 41 meandering in the axial direction of the stator 30. The connecting portions 37, 38, 39 of the respective stator rings 31, 32, 33 are aligned, the U-phase annular winding coil 3 and the W-phase annular coil 4 are arranged at predetermined positions in the circumferential direction, and the respective stator rings 31, 32 are arranged. , 33 are fixed with bolts to complete the stator 30 as shown in FIG.

  As is apparent from FIG. 6, the teeth 34, 35, 36 of each stator ring are in a predetermined order in the circumferential direction (U-phase teeth 34, V-phase teeth 35, W-phase teeth 36, U-phase teeth 34,...). The meandering portion 40 of the U-phase meandering annular coil 3 is arranged between the teeth 34 and 35 adjacent in the circumferential direction, and the meandering portion 41 of the W-phase meandering annular coil 4 is disposed between the teeth 35 and 36 adjacent in the circumferential direction. Is placed. That is, one U-phase tooth 34 is disposed in the U-phase meandering portion 40, and one W-phase tooth 36 is disposed in the W-phase meandering portion 41, and the U-phase meandering portion 40 and the W-phase meandering that are adjacent in the circumferential direction. One V-phase tooth 35 is arranged between the portion 41. The meandering portion 40 of the U-phase meandering annular coil 3 and the meandering portion 41 of the W-phase meandering annular coil 4 are provided so as to protrude in different directions, and the U-phase meandering annular coil 3 and the W-phase meandering annular coil 4 are They are arranged at positions relatively displaced along the circumferential direction so as to have a phase difference of 240 ° in electrical angle. Thus, the two-phase meandering annular coils 3 and 4 arranged so as to sew between the teeth 34 and 35 adjacent to each other in the circumferential direction or between 35 and 36 form a short-pitch winding of a so-called electrical angle of 120 ° or less. It is formed as follows.

  The meandering annular winding coil as described above is formed by the method disclosed in Patent Document 2. This formation is performed using a special molding machine as shown in FIG. This figure is a cross-sectional view of the upper mold unit 12 and the lower mold unit 13 before processing of the molding machine, and the base of the upper mold unit 12 is spaced apart from each other at equal intervals in the circumferential direction. The mold support portion 14 is fixed. A guide rail 17 is attached to each mold support portion 14 by a pair of brackets 15 and 16. A slider 18 is attached along the guide rail 17 so as to be slidable in the radial direction of the circular annular winding 1 to be formed into the meandering annular coil 3 (4). Each slider 18 is provided with a first mold 19 including a pressing portion 20 for forming the circular annular winding 1 and the punch 6 of the present application, and a rotatable roller 21. The roller 21 rolls on a cam surface 28 formed on the roller guide 27 of the lower mold unit 13 as the upper mold unit 12 and the lower mold unit 13 approach each other. For forming a meandering annular coil having ten tops and troughs, the upper mold unit 12 has ten molds 19 spaced apart from each other at equal intervals in the circumferential direction. A plurality of roller guides 22 arranged in the middle of one mold 19 are fixed. A curved cam surface 23 is formed at the tip of each roller guide 22.

  A plurality of mold support parts spaced apart at equal intervals in the circumferential direction are fixed to the base of the lower mold unit 13. Each mold support portion is provided with a guide rail 24 so that the circular annular winding 1 in which the second mold 25 is set can slide along the guide rail 24 in the radial direction. It is attached. Each second mold 25 includes a mold base 51 slidable along the guide rail 24, a coil pressing member 52, and the die 5 of the present application. The roller 26 is rotatably attached to the mold base 51 via a pair of brackets. Since the roller 26 of each second mold 25 is adapted to roll on the cam surface 23 of the roller guide 22 provided in the upper mold unit 12, each second mold 25 is arranged in the circumferential direction. It is spaced apart by 36 ° and is arranged in the middle in the circumferential direction between the adjacent first molds 19. Further, a plurality of roller guides 27 that are spaced apart at equal intervals in the circumferential direction and are respectively disposed in the middle in the circumferential direction of the adjacent second mold 25 are fixed to the lower mold unit 13.

  As shown in FIG. 4, the circular winding coil 1 is prepared by preparing a cylindrical body 42 as shown in FIG. Is wound around the cylindrical body 42 to form an annular coil, which is extracted from the cylindrical body 42 as shown in B, and the coil start end 45 and coil end 46 are raised to form an m-row n-layer circle as shown in C. The annular winding 1 having a shape is formed. Thus, after winding the conducting wire 44 around the cylindrical body 42 to form an annular winding group, as shown in D, the circular annular winding 1 is attached to each second die 25 of the lower die unit 13. Place and hold on the mold base. From this state, as shown by E, the upper mold unit 12 is lowered, and the forming process of the circular annular winding 1 is started. At the time of starting the molding process shown in F, the roller 21 of the upper mold unit 12 comes into contact with a substantially linear portion where the cam surface 28 of the roller guide 27 of the lower mold unit 13 is steeply inclined, and the lower mold unit Since the roller 26 of the mold unit 13 is in contact with a substantially linear portion where the cam surface 23 of the roller guide 22 of the upper mold unit 12 is steeply inclined, the circular annular winding 1 is formed at the initial stage of the molding process. It is only slightly reduced in the radial direction with respect to the axial change amount. When the upper mold unit 12 further moves in the axial direction, the roller 21 rolls on the arc-shaped portion of the cam surface 28, and the roller 26 rolls on the arc-shaped portion of the cam surface 23. Therefore, the upper mold unit As the amount of reduction in the radial direction of the circular annular winding 1 increases gradually with respect to the amount of displacement in the axial direction of 12, the roller 21 tilts the cam surface 28 as the pressing further proceeds as indicated by G. Rolls in a substantially linear part where the roller surface 26 is gentle and the roller 26 rolls in a substantially linear part where the inclination of the cam surface 23 is gentle. Therefore, the radial displacement amount relative to the axial displacement amount of the circular annular winding 1 Will draw a curve. As described above, by adopting the curved cam surfaces 23 and 28 having a special shape as shown in FIG. 5, the circular annular winding 1 can be displaced with respect to the axial displacement amount of the circular annular winding 1. Since the ratio of the amount of displacement in the radial direction can be continuously changed, a plurality of meandering portions 40 (41) are provided on the circular annular winding 1 without applying excessive stress to the circular annular winding 1. Can be easily configured automatically. An annular coil 3 (4) having a plurality of (ten in this example) meandering portions as shown in FIG. 3 is completed.

For example, as shown in FIG. 3, the meandering annular coil has a shape in which a trapezoidal top and a U-shaped trough are alternately repeated. The tip of the U valley portion of the meandering annular coil has a small curvature (R), and the inclination angle formed between the U valley side wall and the trapezoidal surface is 91 °, which is very close to 90 ° (vertical). If the amount of springback (hereinafter abbreviated as SB amount) is taken into consideration, the bending process needs to bend beyond the product dimensions. Depending on the shape of the valley, the tilt angle may be close to 90 °, and the tilt angle in anticipation of the amount of SB may be less than 90 °. In that case, considering normal press working, the mold and the sample interfere with each other on the locus of the movement of the mold, and the molding cannot be performed. If the inclination angle of the meandering annular coil is very close to 90 ° (around 91 °), the inclination angle of the trough is the same as that of the formed springback (SB) even if 90 ° processing, which is the limit value in normal pressing, is performed. Since it spreads from a predetermined angle due to the influence, the finished shape becomes an obtuse angle. In addition, there is a problem that the R shape of the mold can be limited and the predetermined R dimension cannot be obtained.
JP 2006-280190 A "Stator" Published on October 12, 2006 JP 2008-54490 A “Meandering Circular Winding Coil Forming Machine and Meandering Circular Winding Coil Forming Method” Published March 6, 2008

  When the meandering annular coil is formed by the pressing method of Patent Document 2 shown in FIG. 5, the adjacent mold comes closer due to the reduced diameter during forming, but the inclination angle of the valley becomes just 90 °. This is because the clearance between adjacent molds (die and punch) is equal to the coil thickness. In general, in order to prevent deformation due to the SB phenomenon, it is only necessary to perform over-molding in consideration of the amount of SB at the time of molding. In order to finish the meandering annular coil to a predetermined diameter, it is necessary to further reduce the diameter of the die in consideration of the amount of SB. This means that the clearance will be less than the coil thickness and will face mechanical limitations.

  The object of the present invention is to realize the above-mentioned problem in the method of forming a meandering annular coil that is axially pressed while reducing the diameter of the stroke, that is, in order to realize an inclination angle close to 90 ° in view of the springback amount, a die and a punch The purpose of this invention is to present a method for forming a meandering annular coil that solves the mechanical limit problem that the clearance between the coils becomes equal to or less than the coil thickness and forms a desired valley shape.

The valley and top forming method of the meandering annular coil having a desired shape according to the present invention is a pressing process in which one punch enters between two dies to form a valley and a top shape, and the die and the A plurality of punches are alternately arranged in the circumferential direction of the annular coil, and at least one side of the die and the punch facing each other, both the die and the tip end R portion of the punch facing each other have an overhang shape. At the same time, the R dimension of the tip end R portion of the die that is in an overhang shape is set smaller than the product dimension in consideration of the amount of spring back, and the two dies are moved closer to and away from each other as the punch advances and retreats. In consideration of the amount of springback, a steep inclination angle shape was assumed.

The valley and top forming device of the meandering annular coil of the present invention is a press working device in which one punch enters between two dies to form a valley and a top shape, and this device responds to the advance and retreat of the punch. Means for moving the two dies closer to and away from each other, and at least one side of the die and the punch facing each other, both of the tip R portions thereof are overhanged, and the die is overhanged. The R dimension of the tip R part is set to be smaller than the product dimension in consideration of the amount of springback, and the tip shape of both is overhanged by providing a mechanism for the punch to enter with the die open. and is in spite of being, without interfering with each other across a coil having a thickness, the function of processing the steep angle of inclination in the amount of spring back It was obtain things.

The valley forming method of the meandering annular coil having a desired valley shape according to the present invention is a press working in which one punch enters between two dies to form a valley shape, and at least one of the die and the punch is opposed to each other. On the side, both the die and the punch are overhanged, so that the inclination angle of the valley can be formed at an acute angle of 90 ° or less, and the two dies approach as the punch advances and retreats. This is a molding method that enables molding with an appropriate spring back that allows the overhanging die or punch tip R portion to move forward and backward without interfering with each other by being separated. This makes it possible to form a trough having an inclination angle close to 90 ° even when there is a spring back after press forming.
In addition, by arranging a plurality of dies and punches alternately in the circumferential direction of the annular coil, even if there is a spring back after press forming, a plurality of valleys with an inclination angle close to 90 ° can be simultaneously formed with high accuracy. Became possible.

  In the valley forming method of the meandering coil having the desired valley shape according to the present invention, since the punch enters with the die opened in the initial step, the die or the tip R portion shape of the punch overhangs. Can be fitted without interfering with each other, and in the next step, the die enters the punch while the interval between the dies is narrowed, and passes through a predetermined product size to correct a predetermined springback amount. Since the trough shape is stepped up to the pushed position, the punch and die tip R part shape overhangs and presses into a state of engagement with each other, so the inclination angle is formed at an acute angle of 90 ° or less. can do. Further, in the next step, the step of retracting the punch while expanding the distance between the dies on both sides to at least the product dimension is taken to ensure the molding, and the die and the tip R portion shape of the punch are overhanged. Even if they exist, they can be retracted to the initial position without interfering with each other.

The meandering annular coil trough forming apparatus of the present invention comprises means for moving the two dies closer to and away from each other according to the advance and retreat of the punch, and the tips R of both the die and the punch are at least on opposite sides. Since the configuration in which both the portions are overhanged is adopted, the valley shape can be processed into an inclination angle close to 90 ° regardless of the phenomenon of springback.
By considering the springback amount, the R dimension of the tip R portion that has become the overhang shape of the die used in the valley forming method of the meandering annular coil of the present invention is set to be smaller than the product dimension. Even if there is a springback phenomenon, it can be finished closer to the product shape.

  The overall shape of the meandering annular coil is as shown in FIG. 3, but the shape of the trough 10 is not symmetrical, and the rising portion 11a and the falling portion 11b have different inclination angles and bending shapes. . FIG. 1A shows a form of conventional press working, and the upper figure shows the time when the punch entry end point (bottom dead center) is reached. In the figure, θ represents an inclination angle formed by the U valley side wall and the trapezoidal surface. The dies 5 and the punches 6 on both sides mesh with each other to form a product shape. The inclination angle of the falling part 11b is close to 90 °, and when the bottom dead center is reached, the product is pressed into the product shape. After that, the distance between the dies 5 on both sides is increased and the punch 6 is retracted. Then, when the product is taken out, as shown in the lower diagram of FIG. 1A, the angle of the portion bent into the product shape is slightly reduced due to the phenomenon of spring back (SB). When the tilt angle is considerably larger than 90 ° as in the shape of the rising portion 11a, it is possible to press the steeper angle in anticipation of this SB, but the tilt angle is 90 ° as in the falling portion 11b. In the case of an angle close to, if an attempt is made to press at a steeper angle in anticipation of the SB, the die 5 and the punch 6 interfere with each other, so that the engagement becomes impossible and the SB is anticipated. Will not be able to.

Therefore, according to the present invention, on at least one side of the die and the punch facing each other, both the die and the tip R portion facing the punch are both overhanged, and the two dies are moved closer to and away from each other according to the advance and retreat of the punch. Thus, a technique for forming a desired V-shaped or U-shaped valley shape is presented. By using a die and punch whose tip R portion has an overhang shape, the width dimension becomes narrow at the side surface portion other than the tip portion, and a clearance can be secured between the die and the punch. When the punch is retracted after bending at an acute angle using the clearance, it is necessary to avoid the tip R portion having an overhang shape from interfering with the counterpart die or punch. In the present invention, this problem is solved by making the two dies 5 approach and separate as the punch 6 advances and retreats.
Note that the valley shape is not limited to the angle of inclination of both the rising portion 11a and the falling portion 11b being close to 90 °. If only one is steep and the other is gentle, the die and punch It is sufficient if one of the opposed tip R portions has an overhang shape.

  FIG. 1B shows the valley forming method of the present invention. With the dies 5 on both sides open, the punch 6 enters and starts forming the valley shape. Therefore, even if the tip R portion of the both dies 5 has an overhang shape, the tip of the punch 6 has an overhang shape. The portion can pass through this portion with the thickness of the annular winding 1 interposed, and can enter the back of the double-sided die 5. The tip of the punch 6 passes through this portion and enters the back of the die 5 and is further advanced after the annular winding 1 is pressed to the product dimensions, and the distance between the dies 5 on both sides is further narrowed. It becomes a state. This figure shows the time when the bottom dead center is reached, and the projection interval on the radial surface between the tip end R portion of the die that forms the falling portion 11b and the tip end portion of the punch 6 is the workpiece. It becomes below the thickness dimension of a certain coil. The shape of the falling portion 11b of the meandering annular coil is formed at an acute angle by an amount exceeding the thickness dimension. That is, as shown in the above figure, the top of the coil is formed at the tip of the die 5, the R shape is formed at the overhanged shoulder, and the valley bottom is formed at the tip of the punch 6 that is overhanged. Is formed, and the coil is pushed into the side surface of the die 5 where the width dimension is narrowed, and is pressed to an acute inclination angle. After that, as shown in the lower figure, when the distance between the dies 5 on both sides is increased to at least the product size and the punch 6 is retracted and the product is taken out, the bent portion is a springback (SB) phenomenon. Although the angle is slightly distorted, since it has been bent excessively, an inclination angle close to 90 ° of the product shape can be realized. Further, the shape of the tip end portion R of the die 5 having an overhang shape is set to be smaller than the R dimension of the product in consideration of the amount of SB so that a predetermined R dimension can be obtained.

  An example of a die and a punch used in the press working of the meandering annular coil forming the valley shape of the present invention will be described with reference to FIG. In this embodiment, both the shoulder and punch of the die have an overhang shape at the tip R. In the figure, the shape of the solid line display for both the die and the punch is the conventional shape, and the shape of the two-dot chain line display is the shape of this embodiment. The tip portion of the punch 6 having an overhang shape is a thick portion having a size slightly larger than the conventional R shape, and the other portion is a thin portion having a size smaller than the conventional width size. On the other hand, the tip of the overhang-shaped die 5 has different shapes on the rising portion 11a side and the falling portion 11b side of the coil valley portion, the former R shape having a large size and the latter R shape having a small size. It is a dimension. This is because, as described above, the valley shape of the coil to be molded is asymmetric between the rising portion 11a side and the falling portion 11b side, and the former has a gentle inclination angle with the top portion 9, and the latter has the top portion. This is because a steep inclination angle is between 9.

When the above die is opened, the above punch enters, so the tip shape is both overhang, but the punch reaches the bottom dead center without interfering with the thick coil. it can. As can be seen from FIG. 2, the top surface of the coil 3 is in the state where the bottom surface of the coil 3 (4), which is initially in the form of a circular annular winding, is in contact with the tip portion of the die 5. The trough is press-molded. The position of the punch 6 is not close to the center of the dies 5 on both sides but close to the die 5 on the falling part 11b side. The reason for this configuration is that the rising portion 11a cooperates with the tip shape of the die 5 in which the R shape on the rising portion 11a side has a large size and the R shape on the falling portion 11b side has a small size. This is because the coil shape on the side is formed at a gentle inclination angle, and the shape on the falling portion 11b side is formed at a steep inclination angle. In order to finish the shape of the falling portion 11b side to be close to 90 ° (91 ° in this embodiment) with a steep inclination angle, as shown in FIG. The leading end of the punch 6 thus formed forms the meandering annular coil 3 (4) at an inclination angle of 90 ° -α.
Thereafter, the both-side dies 5 are opened and the punch 6 is retracted, and the punch retracts while the distance between the both-side dies is widened to at least the product size. It is separated smoothly. The formed meandering annular coil released from the die 5 and the punch 6 is pressed into an acute angle in anticipation of a slight bending angle due to the SB phenomenon, and the shape on the falling part 11b side is 91 ° of the designed value. Finished with a steep inclination angle close to.

It is a figure explaining the valley formation method of the present invention compared with the conventional method. It is a figure which shows the Example of the die | dye and punch used for the trough formation method of this invention. It is a figure which shows the shape of the annular coil which has a meandering part which concerns on this invention. It is a figure explaining the formation process of the cyclic | annular winding coil which has the conventional several meander part. It is a figure which shows the apparatus which press-molds the conventional cyclic | annular winding coil which has several meandering parts. It is a figure which shows the state which integrated the conventional winding coil of U phase and W phase.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Circular ring winding 3 (4) Ring coil which has meander part 5 Die 6 Punch 9 Top part 10 Valley part
11a Rising part 11b Falling part
12 Upper mold unit for molding 13 Lower mold unit for molding
14 Mold support 15, 16 Bracket
17 Guide rail 18 Slider
19 First mold 20 Holding part
21 Roller 22 Roller guide
23 Cam surface 24 Guide rail
25 Second mold 26 Roller
27 Roller guide 28 Cam surface
30 Stator 31 U-phase stator ring
32 V-phase stator ring 33 W-phase stator ring
34 U-phase teeth 35 V-phase teeth
36 W phase teeth 37, 38, 39 joint
40, 41 Meandering part 42 Cylindrical body
44 Conductor 45 Coil start
46 Coil termination 51 Mold base
52 Coil retainer

Claims (2)

A press work in which one punch enters between two dies to form a valley and a top shape, and a plurality of the dies and punches are alternately arranged in the circumferential direction of the annular coil. On at least one side of the punch facing each other, both the die and the tip R portion facing the punch are both in an overhang shape, and the R dimension of the tip R portion in the die overhang shape is a spring. It is set to be smaller than the product size expected to back amount, by toward and away from the two dies according to advance and retreat of the punch, valleys of the serpentine annular coil and to steep inclination angle shape by the amount of spring back Top molding method. A press working device in which one punch enters between two dies to form a valley and a top shape, and this device comprises means for moving the two dies closer to and away from each other according to the advance and retreat of the punch, On at least one side of the die and the punch facing each other, both the tip R portions have an overhang shape, and the R dimension of the tip R portion having the overhang shape of the die assumes a springback amount. Even if a thick coil is sandwiched between the two when the punch enters when the die is open with the die set open, the tip shape of both ends is overhanging. A device for forming a valley portion and a top portion of a meandering annular coil having a function of processing into a steep inclination angle in anticipation of a springback amount without performing the above.

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