Coil assembly and stepper motor using the same

Abstract

The present invention provides a coil assembly that can loosen a coil wire without increasing assembly costs, and a stepping motor using the coil assembly. The coil assembly comprises: a bobbin (232) having flanges (233, 234) at both ends; a plurality of terminal pin embedding portions (235a) provided at one flange portion (234); a terminal pin (236) embedded in the terminal pin embedding portion (235a); and a coil (231), the end of the coil wire (237) being wound around the bobbin (232) by being wound around the terminal pin (236). A recess (238) is provided between the terminal pin embedded portions (235a), which is recessed radially toward the winding tube (232) and passes through the winding tube (232) in the axial direction. The coil wire (237) is wound around the winding tube (232) from the base of the terminal pin (236) through the recess (238), and a slack portion (237a) is provided inside the recess (238).

Description

Technical Field

[0001] The present invention relates to a coil assembly forming slack at the end of a coil and a stepper motor using the coil assembly. Background Art

[0002] Conventionally, as a stepping motor, there is a known PM (Permanent Magnet) type stepping motor having a rotor composed of permanent magnets and a stator, wherein the stator has a plurality of pole teeth protruding axially from the outer periphery of the rotor and arranged circumferentially. The PM type stepping motor combines an outer yoke having a plurality of pole teeth arranged in a ring shape and an inner yoke having a plurality of pole teeth arranged in a ring shape, and a coil is accommodated inside the outer yoke and the inner yoke to form a stator. Furthermore, the rotor composed of permanent magnets is arranged in a state where it can rotate relative to the stator.

[0003] Here, the coil wire is wound around the bobbin by an automatic winding machine, but the coil wire connected to the terminal pin of the terminal block provided on the bobbin is in a tensioned state. In particular, the winding start side is wound from above the coil wire connected to the terminal pin in a manner that presses the coil wire connected to the terminal pin, thereby applying tension to the short portion of the coil wire. If assembly is performed in a state where this tension remains, there is a concern that the coil wire may break, so it is necessary to form slack in the coil wire located near the terminal pin. As a method for forming slack in the coil wire, for example, the method described in Japanese Patent Gazette No. 2011-78152 is known.

[0004] This document describes a method for manufacturing a motor in which, when assembling a bobbin to a stator, a terminal block integrated with the bobbin is pressed from the inside by the stator to move radially outward, thereby creating slack in a coil wire lead portion near a terminal pin.

[0005] In the method described in the above document, the terminal block needs to be pressed radially outward from the stator part. Therefore, the following method needs to be adopted: a method of connecting the bobbin and the stator part in a state where the terminal block of the bobbin is deformed radially outward in advance, or a method of making the stator part contact the inner side of the terminal block of the bobbin from an oblique direction and pressing the terminal block in the radial outward direction, maintaining this state and embedding the stator part into the inner side of the bobbin.

[0006] However, the former method is complicated in operation and there is a concern that the terminal block may be damaged due to excessive deformation of the terminal block. In addition, the latter method is difficult to insert into the hole of the circuit board due to deviation in component size and inclination of the terminal block, which may reduce workability. Summary of the invention

[0007] The present invention has been made in view of the above problems, and an object of the present invention is to provide a coil assembly capable of forming slack in a coil wire without simplifying the work and increasing the assembly cost, and a stepping motor using the coil assembly.

[0008] The coil assembly of the present invention comprises: a winding tube having flange portions at both ends; a plurality of terminal pin embedded portions arranged on one side of the flange portions; a terminal pin embedded in the terminal pin embedded portion; and a coil, wherein the ends of the coil wire are wound around the terminal pins and wound around the winding tube, and recesses are provided between the terminal pin embedded portions, which are radially recessed in the winding tube and pass through the axial direction of the winding tube, and the coil wire is wound around the winding tube from the base of the terminal pin through the recess, and a slack portion is provided inside the recess.

[0009] The coil assembly of the above structure is manufactured as follows. First, a slack forming pin is inserted into a recess between the terminal pin embedded parts from the axial direction of the bobbin. In this state, the end of the coil wire is wound around the terminal pin, so that the coil wire is hung on the slack forming pin and wound around the bobbin. After the coil wire is wound around the bobbin for a specified amount, the terminal end of the coil wire is wound around another terminal pin. Then, by pulling out the slack forming pin from the recess, the part of the coil wire hung on the slack forming pin becomes a slack portion. In this way, in the coil assembly of the present invention, a slack portion can be formed in the coil wire by a simple operation such as inserting the slack forming pin into the recess and pulling it out. In addition, since the slack portion exists in the recess, it is possible to suppress the trouble of causing a malfunction in the winding of the coil wire due to the centrifugal force when the bobbin is installed on the main shaft of the winding machine and the coil wire is wound. In addition, when the coil wire is wound around the bobbin, since the slack portion is located in the recess, it will not protrude to the inside of the bobbin, so it is possible to prevent the coil wire from being wound into the slack portion.

[0010] In the coil assembly manufactured as described above, the slack portion has a shape along the outer periphery of the slack forming pin, and the slack forming pin is inserted into the recessed portion freely. If the cross section of the slack forming pin is circular, the slack portion becomes a curved shape, and the wire is not easily broken even when tension is applied to the coil wire.

[0011] The coil wire is preferably wound from the middle portion of the terminal pin in the long side direction to the terminal pin embedded portion. Since the coil wire is provided with an insulating coating, the wound portion is subjected to soldering to be connected to the terminal pin. When the wound portion of the terminal pin is soldered by dipping, jetting, etc., there is a concern that the solder will adhere to the loose portion if the loose portion protrudes beyond the surface of the terminal pin embedded portion. However, since the loose portion is located in the recessed portion, it will not protrude beyond the surface of the terminal pin embedded portion, so that the solder can be prevented from adhering to the loose portion.

[0012] The present invention is also a stepping motor having the coil assembly as described above. That is, the present invention is a stepping motor having a stator and a rotor rotatably supported on the inner circumference of the stator, wherein the stator has an outer yoke and an inner yoke mounted so as to sandwich the coil assembly.

[0013] According to the present invention, there are provided a coil assembly capable of forming a slack portion in a coil wire without simplifying the work and increasing the assembly cost, and a stepping motor using the coil assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is an exploded perspective view of a stepping motor according to an embodiment of the present invention.

[0015] Figure 2 It is an exploded perspective view of the A-phase stator unit in the embodiment of the present invention.

[0016] Figure 3 It is a perspective view showing a coil assembly in the embodiment of the present invention.

[0017] Figure 4 Observe from the opposite direction Figure 3 A three-dimensional view of the coil assembly.

[0018] Figure 5 This is a perspective view showing a state where a bobbin is mounted on a main shaft of a winding machine and a coil wire is wound thereon.

[0019] Figure 6 yes Figure 5 Exploded three-dimensional diagram.

[0020] Figure 7 Yes means Figure 5 An enlarged stereogram of the main parts.

[0021] Description of Reference Numerals

[0022] 100…stepping motor; 200…A-phase stator unit; 210…front plate; 211…opening; 220…outer yoke; 221…circular ring; 222…outer cylinder; 222a…cutout; 223…pole tooth; 230…coil assembly; 231…coil; 232…bobbin; 233…flange; 234…flange; 235…terminal block; 235a…terminal pin embedding portion; 235b…terminal pin press-in hole; 236…terminal pin; 237…coil wire; 237a…slack portion; 238…recess; 240…inner yoke; 241…circular ring portion; 241a…cut-out portion; 243…pole tooth; 250…bearing; 260…bearing; 300…B-phase stator unit; 310…end plate; 311…opening portion; 320…outer yoke; 322a…cut-out portion; 330…coil assembly; 340…inner yoke; 341a…cut-out portion; 400…rotor; 401…shaft; 500…stator; 600…spindle; 601…body; 602…bobbin receiver; 603…shank; 604…pedestal; 604a…recess; 605…screw; 606…loose-forming pin; 607…pressing member. DETAILED DESCRIPTION

[0023] 1. Structure of stepper motor

[0024] (Overall structure)

[0025] Figure 1 A stepper motor 100 according to an embodiment is shown. The stepper motor 100 is a claw-pole two-phase PM (Permanent Magnet) stepper motor. The stepper motor 100 includes a stator 500. The stator 500 has a structure that connects an A-phase stator unit 200 and a B-phase stator unit 300 in the axial direction. Here, the A-phase stator unit 200 and the B-phase stator unit 300 have the same structure, and the stator 500 is formed by flipping one of them in the axial direction relative to the other so that their back surfaces contact and connect with each other.

[0026] The front plate 210 is fixed to the A-phase stator unit 200, and the end plate 310 is fixed to the B-phase stator unit 300. The stator 500 has a substantially cylindrical shape, and the rotor 400 is rotatably accommodated inside the stator 500.

[0027] (Structure of A-phase stator unit 200)

[0028] Figure 2 FIG. 2 is an exploded perspective view of the A-phase stator unit 200. Figure 2As shown, the A-phase stator unit 200 has a structure in which an outer yoke 220, a coil assembly 230, and an inner yoke 240 are connected axially. The outer yoke 220 is a part that functions as a yoke that forms a magnetic circuit, and is made of magnetic materials such as electromagnetic soft iron or rolled steel plate. The outer yoke 220 has a plate-shaped annular portion 221, a cylindrical outer cylinder portion 222 extending axially from the outer edge of the annular portion 221, and a plurality of roughly triangular-shaped pole teeth 223 extending axially from the edge of the inner circumference of the annular portion 221 and arranged at intervals along the circumferential direction. A cutout portion 222a is formed in the outer cylinder portion 222 for embedding the terminal block 235 described later. The coil assembly 230 wound with the coil (stator coil) 231 is arranged in an annular space between the outer cylinder portion 222 of the outer yoke 220 and the plurality of pole teeth 223. In addition, the structure of the coil assembly 230 will be described in detail later.

[0029] The inner yoke 240 is a part that functions as a yoke that forms a magnetic circuit, and is made of a magnetic material such as electromagnetic soft iron or rolled steel plate. The inner yoke 240 includes a plate-shaped annular portion 241, and a plurality of substantially triangular-shaped pole teeth 243 extending axially from the edge of the inner circumference of the annular portion 241 and arranged at intervals along the circumferential direction. A cutout portion 241a is formed in the annular portion 241 for the terminal block 235 to be embedded. The pole teeth 243 of the inner yoke 240 are combined with the pole teeth 223 of the outer yoke 220 in a manner that they are alternately meshed in the circumferential direction.

[0030] The same component as the inner yoke 240 of the A-phase stator unit 200 is axially reversed to form the inner yoke 340 of the B-phase stator unit 300. The A-phase stator unit 200 and the B-phase stator unit 300 are connected by making the inner yoke 240 and the inner yoke 340 face and contact with each other with the same surface.

[0031] The surface of the annular portion 221 of the outer yoke 220 opposite to the side facing the coil assembly 230 is connected to the front plate 210. The front plate 210 has a circular opening 211 at the center, and a bearing 250 is mounted in the opening 211.

[0032] (Structure of B-phase stator unit 300)

[0033] The B-phase stator unit 300 has the same structure as the A-phase stator unit 200, and the components of the same structure as the A-phase stator unit 200 are used in an axially flipped state. The B-phase stator unit 300 has a structure in which an outer yoke 320, a coil assembly 330, and an inner yoke 340 are combined in the axial direction. Here, the outer yoke 320 is a component of the same structure as the outer yoke 220, and the coil assembly 330 is a component of the same structure as the coil assembly 230. The outer yoke 320 is connected to the end plate 310. The end plate 310 has a circular opening 311 at the center, and the bearing 260 is installed in the opening 311.

[0034] (Rotor Structure)

[0035] The rotor 400 has a substantially cylindrical structure and has a permanent magnet such as a ferrite magnet or a rare earth magnet on its outer periphery. The permanent magnet has a magnetic pole structure in which the magnetic poles are alternately flipped in the circumferential direction to be NSNS. The shaft 401 is fixed to the axial center of the rotor 400 in a state of passing through in the axial direction. Figure 1 The end portion protruding to the left is rotatably supported by the front plate 210 via a bearing 250 , and the end portion of the shaft 401 protruding to the right from the rotor 400 is rotatably supported by the end plate 310 via a bearing 260 .

[0036] 2. Structure of coil assembly

[0037] like Figure 3 and Figure 4 As shown, the coil assembly 230 has a bobbin 232, on which a coil wire 237 constituting a coil 231 having a coaxial structure with the center of the axis is wound. The bobbin 232 is made of resin and is formed using an injection molding method. Flange portions 233 and 234 are formed at both ends of the bobbin 232 in the axial direction to prevent the coil 231 from unwinding. A terminal block 235 is formed on the flange portion 234 on one side. The terminal block 235 is a rectangular block protruding axially from the flange portion 234, and is integrally formed with the flange portion 234. A plurality of (three in the present embodiment) terminal pin embedded portions 235a are formed on the terminal block 235, and a recess 238 is formed between the terminal pin embedded portions 235a.

[0038] In the terminal pin embedding portion 235a, a plurality of (two in this embodiment) metal terminal pins 236 are embedded by press-fitting, insert molding, etc. The end of the coil wire 237 of the coil 231 is wound around the terminal pin 236. Between the terminal pin embedding portions 235a, a recessed portion 238 is formed that is recessed toward the lower side in the figure and penetrates in the axial direction. Figure 3 A slack portion 237a of the coil wire 237 is formed in the recessed portion 238 on the middle right side. The slack portion 237a is a portion where the coil wire 237 starts winding.

[0039] like Figure 2 As shown, the coil assembly 230 having the above structure is connected to the outer yoke 220 and the inner yoke 240 in a manner of being clamped therebetween, and the terminal block 235 is embedded in the cutout portion 222a of the outer yoke 220 and the cutout portion 241a of the inner yoke 240 to form the A-phase stator unit 200. Figure 1 As shown, the coil assembly 330 is similarly connected to the outer yoke 320 and the inner yoke 340 in a manner of being sandwiched therebetween, and the B-phase stator unit 300 is formed in a state where the terminal block 235 is embedded in the cutout portion 322 a of the outer yoke 320 and the cutout portion 341 a of the inner yoke 340 .

[0040] 3. Formation steps of coil assembly

[0041] Reference Figure 5 to Figure 7 The steps of forming the coil assembly 230 are described below. Figure 5 In the figure, reference numeral 600 is the main shaft of the automatic winding machine, which is installed on the main body of the automatic winding machine and rotates. Figure 6 As shown, the spindle 600 includes a main body 601 formed of a substantially rectangular block, a disk-shaped bobbin receiver 602, and a handle 603 to be held by the main body of the automatic winding machine.

[0042] A pedestal 604 is mounted on the upper surface of the main body 601 by means of screws 605. A slack forming pin 606 is mounted on the pedestal 604. The base of the slack forming pin 606 is formed relatively thick to ensure rigidity. A recess 604a is formed on the axial side of the pedestal 604, and the terminal block 235 is engaged with the recess 604a to be positioned. In addition, reference numeral 607 in the figure is a pressing component for fixing the bobbin 232 mounted on the bobbin receiver 602. The pressing component 607 is moved toward the main body 601 side by a driving mechanism not shown in the figure, and cooperates with the main body 601 to clamp the coil assembly 230, and rotates with the main shaft 600 in this state.

[0043] Next, the steps of winding the coil wire 237 on the bobbin 232 to form the coil assembly 230 are described. First, the bobbin 232 is installed on the bobbin receiver 602 by manual operation or a robot, and the pressing member 607 is installed on the bobbin receiver 602, and the bobbin 232 is clamped by the main body 601 and the pressing member 607. At this time, the front end of the small diameter of the slack forming pin 606 is inserted into the recess 238 formed between the terminal pin embedded parts 235a. Figure 7 As shown, a cylindrical curved surface 238 a is formed at a corner of the recessed portion 238 , and the outer peripheral surface of the slack forming pin 606 is arranged at a position in contact with or extremely close to the cylindrical curved surface 238 a .

[0044] The automatic winding machine has a three-dimensional movable nozzle for feeding the coil wire 237. First, the coil wire 237 fed from the nozzle is wound around the terminal pin 236. After the coil wire 237 is wound around the terminal pin embedded portion 235a, the nozzle hooks the coil wire 237 to the slack forming pin 606 and guides it to the main body of the winding tube 232. In this state, the spindle 600 moves along the direction from Figure 5 The coil wire 237 is wound around the bobbin 232 by rotating counterclockwise when viewed from the right side. At this time, tension acts on the coil wire 237 and applies bending stress to the slack forming pin 606, but the slack forming pin 606 is supported by the cylindrical curved surface 238a of the recess 238, which suppresses or even prevents its deformation. During the winding of the coil wire 237, the nozzle moves axially to align the coil wire 237. When the winding of the coil wire 237 is completed, the spindle 600 stops, and the nozzle delivers the coil wire 237, which will become the winding terminal, while winding it around the terminal pin 236 on the other side.

[0045] After the winding of the coil wire 237 is completed, the nozzle cuts the coil wire 237. Then, the pressing member 607 is retracted and removed from the bobbin receiver 602, and the coil assembly 230 wound with the coil wire 237 is removed from the main shaft 600 by manual operation or a robot or the like. As a result, the slack forming pin 606 is pulled out of the recess 238, and the tension applied to the coil wire 237 at the start of winding is released, and as a result, a slack portion 237a remains in the recess 238.

[0046] In the coil assembly 230 having the above structure, the slack forming pin 606 is inserted into the recess 238 of the terminal block 235, the coil wire 237 is wound around the bobbin 232, and the slack forming pin 606 is pulled out after the winding, thereby forming the slack portion 237a in the coil wire 237. In addition, since the slack portion 237a exists in the recess 238, it is possible to prevent the slack portion 237a from fluctuating due to centrifugal force when the bobbin 232 is mounted on the main shaft 600 of the automatic winding machine and the coil wire 237 is wound, thereby preventing the trouble such as winding failure. In addition, when the coil wire 237 is wound around the bobbin 232, since the slack portion 237a is located in the recess 238, it does not protrude toward the inner surface of the flange portion 234, and thus it is possible to prevent the slack portion 237a from being wound.

[0047] In particular, in the above embodiment, the slack portion 237a has a shape along the outer periphery of the slack forming pin 606 inserted into the recess 238. Since the cross section of the slack forming pin 606 is circular, the slack portion 237a has a curved shape, so that the coil wire 237 is not easily broken even when tension is applied.

[0048] In the above embodiment, the coil wire 237 is wound around the terminal pin embedded portion 235a from the middle portion in the longitudinal direction of the terminal pin 236. Since the coil wire 237 is provided with an insulating film, the wound portion is subjected to soldering to be electrically connected to the terminal pin 236. When the wound portion of the terminal pin is soldered by dipping, jetting, or the like, if the slack portion 237a protrudes from the surface of the terminal pin embedded portion 235a, there is a concern that the solder may adhere to the slack portion 237a. However, since the slack portion 237a is located in the recess 238, it does not protrude from the surface of the terminal pin embedded portion 235a, so it is possible to suppress the solder from adhering to the slack portion 237a.

[0049] 4. Change Examples

[0050] The above embodiment is applied to a single-wire winding (bipolar drive) in which there are two terminal pins 236 and one coil wire 237. The present invention can also be applied to a double-wire winding (unipolar drive) in which there are three terminal pins 236 and two coil wires 237. In this case, the terminal pin 236 is pressed into the Figure 7 The terminal pin pressing hole 235b of the central terminal pin embedding portion 235a shown in the figure is also used to start winding the coil wire 237 from the terminal pin 236. Therefore, in this case, the coil wire 237 is fed out from two nozzles provided in the automatic winding machine (not shown), and after the winding start end portion is wound around the terminal pin 236 on one end side and the terminal pin 236 embedded in the central terminal pin embedding portion 235a, each coil wire 237 is hung on each slack forming pin 606 inserted into the recess 238 and wound around the bobbin 232 with a predetermined number of turns. After the coil wire 237 is wound, each nozzle winds the coil wire 237, which will become the winding end, around the central terminal pin 236 and the terminal pin 236 on the other end side. In this way, the slack portion 237a formed at each winding start end is located in the recess 238.

[0051] In the above embodiment, two slack forming pins 606 are mounted on the base 604. Since the slack forming pins 606 for forming the slack portion 237a in the coil wire 237 at the start of winding are provided, this can be applied to both single-wire winding and double-wire winding. In addition, as long as the slack forming pins 606 for forming the slack portion 237a in the coil wire 237 at the start of winding are provided on the base 604, it is of course possible to use them exclusively for single-wire winding and double-wire winding.

[0052] In the above embodiment, a plurality of terminal pin embedding portions 235a are provided in the terminal block 235, but a plurality of terminal blocks (terminal pin embedding portions) may be formed separately from each other in the flange portion 234, so that the terminal blocks can be used as recesses. Even in this embodiment, the slack forming pin 606 is inserted into the recess, and a slack portion 237a can be formed in the coil wire 237 in the same manner as in the above embodiment.

[0053] In the above embodiment, the slack portion 237a is formed when the coil wire 237 starts to be wound around the bobbin 232, but the slack portion 237a may be formed at the end of the winding as needed. In this case, the slack forming pin 606 is arranged at the left corner of the recess 238 facing the main shaft 600.

[0054] The present invention is not limited to the claw-pole type two-phase stepping motor as in the above-described embodiment, but can be applied to any stepping motor such as a hybrid stepping motor.

[0055] The present invention can be used in the technical field of stepper motors.

Claims

1. A coil assembly, wherein: have: The bobbin has flanges at both ends; A plurality of terminal pin embedding portions provided on one side of the flange portion; a terminal pin embedded in the terminal pin embedding portion and extending radially outward from the flange portion; as well as The coil wire end is wound around the terminal pin and wound around the bobbin. A recessed portion is provided between the terminal pin embedded portions, the recessed portion being recessed in the radial direction of the bobbin and penetrating in the axial direction of the bobbin. The coil wire is wound around the bobbin from the base of the terminal pin through the recess and has a slack portion inside the recess. The slack portion is slack in a direction in which the terminal pin extends.

2. The coil assembly according to claim 1, wherein: The slack portion has a shape along the outer periphery of a slack forming pin, and the slack forming pin is inserted into the recessed portion so as to be able to move forward and backward.

3. The coil assembly according to claim 1, wherein: The terminal pin embedded portion is provided in a terminal block formed on one side of the flange portion, and the coil wire is wound from the terminal pin to the terminal block.

4. The coil assembly according to claim 2, wherein: The terminal pin embedded portion is provided in a terminal block formed on one side of the flange portion, and the coil wire is wound from the terminal pin to the terminal block.

5. A stepper motor, wherein: have: stator; and a rotor rotatably supported on the inner circumference of the stator, The stator includes an outer yoke and an inner yoke which are mounted so as to sandwich the coil assembly according to claim 1 .

6. A stepper motor, wherein: have: stator; and a rotor rotatably supported on the inner circumference of the stator, The stator includes an outer yoke and an inner yoke which are mounted so as to sandwich the coil assembly according to claim 2 .

7. A stepper motor, wherein: have: stator; and a rotor rotatably supported on the inner circumference of the stator, The stator includes an outer yoke and an inner yoke which are mounted so as to sandwich the coil assembly according to claim 3 .

8. A stepper motor, wherein: have: stator; and a rotor rotatably supported on the inner circumference of the stator, The stator includes an outer yoke and an inner yoke which are mounted so as to sandwich the coil assembly according to claim 4 .

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