Coil assembly and stepping motor using same

Abstract

To provide a coil assembly capable of forming slack on a coil wire without increasing an assembly cost, and a stepping motor using the same.SOLUTION: A coil assembly includes: a bobbin 232 having flange units 233 and 234 at both ends; a plurality of terminal pin embedded units 235a provided on one flange unit 234; a terminal pin 236 buried in the terminal pin embedded unit 235a; and a coil 231 in which an end unit of a coil wire 237 is bound to the terminal pin 236 and wound about the bobbin 232. A recess 238 is provided that becomes depressed in a radial direction of the bobbin 232 between the terminal pin embedded units 235a and penetrates the bobbin 232 in an axial direction. The coil wire 237 is wound starting from a base unit of the terminal pin 236 through the recess 238 to the bobbin 232 and has a slack unit 237a inside the recess 238.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a coil assembly in which slack is formed at the ends of the coil, and a stepping motor using the same. [Background technology]

[0002] Conventionally, a known stepping motor is a PM (Permanent Magnet) stepping motor, which includes a rotor made of a permanent magnet and a stator with multiple pole teeth axially protruding from the outer periphery and arranged circumferentially. This PM stepping motor combines an outer yoke with multiple pole teeth arranged in an annular pattern and an inner yoke with multiple pole teeth arranged in an annular pattern, with a coil housed inside the outer yoke and inner yoke. The rotor made of a permanent magnet is then arranged rotatably relative to the stator.

[0003] Here, the coil wire is wound onto the bobbin by an automatic winding machine, but the coil wire that is twisted and connected to the terminal pin on the terminal block of the bobbin is under tension. In particular, at the beginning of winding, the coil wire is wound over the twisted and connected coil wire so as to press down on the twisted and connected coil wire, so a short portion of the coil wire is under tension. If this tension is left in the coil wire during assembly, there is a risk of the coil wire breaking, so it is necessary to create slack in the coil wire located near the terminal pin. For example, the method described in Patent Document 1 is known as a method for creating slack in the coil wire.

[0004] Patent document 1 describes a method for manufacturing a motor in which, when the bobbin is assembled to the stator part, the terminal block integrated with the bobbin is pushed from the inside by the stator part, moving radially outward, creating slack in the portion of the coil wire routed near the terminal pin. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-78152 Summary of the Invention [Problem to be solved by the invention]

[0006] In the method described in Patent Document 1, the terminal block needs to be pushed radially outward from the stator portion, which requires either a method of joining the bobbin and the stator portion in a state in which the terminal block of the bobbin is deformed radially outward in advance, or a method of bringing the stator portion into contact with the inside of the terminal block of the bobbin at an angle to press the terminal block radially outward, and then fitting the stator portion into the inside of the bobbin while maintaining this state.

[0007] However, the former method is cumbersome and may cause damage to the terminal block due to excessive deformation, while the latter method may cause variations in component dimensions, which may cause variations in the inclination of the terminal block, resulting in variations in the pitch between the terminal pins and the size of the circuit board. hole This may make it difficult to insert the terminal pin into the connector, resulting in reduced workability.

[0008] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a coil assembly that can form slack in the coil wire by simplifying the assembly process and without increasing assembly costs, and a stepping motor using the same. [Means for solving the problem]

[0009] The present invention relates to a bobbin having flanges at both ends, a terminal block provided on one of the flanges, a plurality of terminal pin embedding portions provided on the terminal block, and a terminal pin embedded in the terminal pin embedding portion. Extending radially outward of the flange portionThe terminal block includes a terminal pin and a coil in which an end of a coil wire is wound around the terminal pin and the end of the coil wire is wound around the bobbin. The terminal block includes a recess between the terminal pin embedded portions, the recess being recessed in the radial direction of the bobbin and penetrating the bobbin in the axial direction. The coil wire starts to be wound around the bobbin from the base of the terminal pin through the recess, and has a slack portion inside the recess, and the slack portion is: The terminal pin extends It is a coil assembly that is loose in the direction.

[0010] The coil assembly having the above configuration is manufactured as follows. First, a slack-forming pin is inserted axially into the recess between the terminal pin-embedded portions of the bobbin. In this state, an end of the coil wire is wound around the terminal pin, and the coil wire is then wound around the bobbin by hanging it on the slack-forming pin. After a predetermined number of turns of the coil wire are wound around the bobbin, the end of the coil wire is hung on another terminal pin. Then, the slack-forming pin is removed from the recess, and the portion of the coil wire that was hanging on the slack-forming pin becomes a slack portion. In this way, with the coil assembly of the present invention, a slack portion can be formed in the coil wire by the simple operation of inserting and removing the slack-forming pin from the recess. Furthermore, because the slack portion exists within the recess, problems such as the slack portion moving around due to centrifugal force and interfering with the winding of the coil wire can be prevented when the bobbin is attached to the spindle of a winding machine and the coil wire is wound. Furthermore, when winding the coil wire around the bobbin, the slack portion is positioned within the recess and does not protrude inside the bobbin, preventing the coil wire from getting wrapped around the slack portion.

[0011] In the coil assembly manufactured as described above, the slack portion has a shape that follows the outer periphery of the slack forming pin that is inserted so as to be able to move back and forth in the recess. If the cross section of the slack forming pin is circular, the slack portion will have a curved shape, making it less likely to break even when tension is applied to the coil wire.

[0012] The coil wire is desirably wound from the longitudinal middle of the terminal pin to the terminal pin embedded portion. Because the coil wire is provided with an insulating coating, the wound portion is soldered to establish electrical continuity with the terminal pin. When soldering the wound portion of the terminal pin using a dip method, a jet method, or the like, if the loosened portion protrudes beyond the surface of the terminal pin embedded portion, there is a risk that the solder will adhere to the loosened portion. However, because the loosened portion is located within the recess, it does not protrude beyond the surface of the terminal pin embedded portion, and therefore solder can be prevented from adhering to the loosened portion.

[0013] The present invention also relates to a stepping motor equipped with the coil assembly described above. That is, the present invention is a stepping motor equipped with a stator and a rotor rotatably supported on the inner periphery of the stator, the stator having an outer yoke and an inner yoke attached to sandwich the coil assembly. [Effects of the Invention]

[0014] According to the present invention, a coil assembly that can form a slack portion in a coil wire by simplifying the assembly process and without increasing assembly costs, and a stepping motor using the same are provided. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is an exploded perspective view of a stepping motor according to an embodiment of the present invention. [Figure 2] FIG. 2 is an exploded perspective view of an A-phase stator unit according to an embodiment of the present invention. [Figure 3] FIG. 2 is a perspective view showing a coil assembly according to an embodiment of the present invention. [Figure 4] FIG. 4 is a perspective view of the coil assembly of FIG. 3 as seen from the opposite direction. [Figure 5] FIG. 2 is a perspective view showing a state in which a bobbin is attached to a spindle of a winding machine and a coil wire is wound around the bobbin. [Figure 6] FIG. 6 is an exploded perspective view of FIG. 5. [Figure 7] FIG. 6 is an enlarged perspective view showing a main part of FIG. 5. DETAILED DESCRIPTION OF THE INVENTION

[0016] 1. Stepping motor configuration (Overall composition) FIG. 1 shows a stepping motor 100 according to an embodiment. The stepping motor 100 is a two-phase claw-pole PM (Permanent Magnet) stepping motor. The stepping motor 100 includes a stator 500. The stator 500 has a structure in which an A-phase stator unit 200 and a B-phase stator unit 300 are coupled in the axial direction. 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 unit over relative to the other in the axial direction and bringing their back surfaces into contact with each other and coupling them together.

[0017] A front plate 210 is fixed to the A-phase stator unit 200, and an end plate 310 is fixed to the B-phase stator unit 300. The stator 500 has a generally cylindrical shape, and the rotor 400 is housed inside the stator 500 in a freely rotatable state.

[0018] (Configuration of A-phase stator unit 200) FIG. 2 shows an exploded perspective view of the A-phase stator unit 200. As shown in FIG. 2, 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 axially connected. The outer yoke 220 functions as a yoke that forms a magnetic path and is made of a magnetic material such as soft magnetic iron or rolled steel plate. The outer yoke 220 includes a plate-shaped annular portion 221, a cylindrical outer tube portion 222 that extends axially from the outer edge of the annular portion 221, and a plurality of approximately triangular pole teeth 223 that extend axially from the inner edge of the annular portion 221 and are spaced apart along the circumferential direction. The outer tube portion 222 has a notch 222a into which a terminal block 235 (described later) fits. The coil assembly 230, around which a coil (stator coil) 231 is wound, is disposed in the annular space between the outer tube portion 222 of the outer yoke 220 and the plurality of pole teeth 223. The configuration of the coil assembly 230 will be explained in detail later.

[0019] The inner yoke 240 functions as a yoke in which a magnetic path is formed, and is made of a magnetic material such as soft magnetic iron or rolled steel plate. The inner yoke 240 includes a plate-shaped annular portion 241 and a plurality of approximately triangular pole teeth 243 that extend axially from the inner peripheral edge of the annular portion 241 and are spaced apart along the circumferential direction. The annular portion 241 is formed with a notch 241a into which the terminal block 235 fits. The pole teeth 243 of the inner yoke 240 are combined so as to alternately mesh with the pole teeth 223 of the outer yoke 220 in the circumferential direction.

[0020] The inner yoke 340 of the B-phase stator unit 300 is the same member as the inner yoke 240 of the A-phase stator unit 200, but flipped in the axial direction. The A-phase stator unit 200 and the B-phase stator unit 300 are coupled by bringing the inner yoke 240 and the inner yoke 340 into contact with each other with the same surfaces facing each other.

[0021] A front plate 210 is coupled to the surface of the annular portion 221 of the outer yoke 220 opposite to the side facing the coil assembly 230. The front plate 210 has a circular opening 211 in its center, and a bearing 250 is attached to this opening 211.

[0022] (Configuration of B-phase stator unit 300) The B-phase stator unit 300 has the same structure as the A-phase stator unit 200, and is used by rotating the A-phase stator unit 200 in the axial direction. 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 with the same structure as the outer yoke 220, and the coil assembly 330 is a component with the same structure as the coil assembly 230. An end plate 310 is connected to the outer yoke 320. The end plate 310 has a circular opening 311 in its center, and a bearing 260 is attached to this opening 311.

[0023] (Rotor configuration) Rotor 400 has a generally cylindrical structure and is provided with permanent magnets such as ferrite magnets or rare earth magnets on its outer periphery. These permanent magnets have a magnetic pole structure in which the magnetic poles are alternately polarized in the circumferential direction in the NSNS pattern. Shaft 401 is fixed to the axial center of rotor 400 and penetrates it in the axial direction. The end of shaft 401 protruding from rotor 400 to the left in FIG. 1 is rotatably supported by front plate 210 via bearing 250, and the end of shaft 401 protruding from rotor 400 to the right is rotatably supported by end plate 310 via bearing 260.

[0024] 2. Coil assembly configuration As shown in FIGS. 3 and 4, coil assembly 230 has bobbin 232 around which coil wire 237 is wound, constituting coil 231 having a coaxial structure with its axis center. Bobbin 232 is made of resin and formed using an injection molding method. Flange portions 233 and 234 are formed on both axial ends of bobbin 232 to prevent coil 231 from becoming unwound. One of flange portions 234 is formed with terminal block 235. Terminal block 235 is a rectangular block that protrudes axially from flange portion 234 and is molded integrally with flange portion 234. Multiple (three in this embodiment) terminal pin embedding portions 235a are formed in terminal block 235, and recesses 238 are formed between terminal pin embedding portions 235a.

[0025] A plurality of metal terminal pins 236 (two in this embodiment) are embedded in the terminal pin embedding portions 235a by means of press-fitting, insert molding, or the like. Ends of the coil wire 237 of the coil 231 are wound around the terminal pins 236. Recesses 238 that are recessed downward in the drawing and penetrate axially are formed between the terminal pin embedding portions 235a. A slack portion 237a of the coil wire 237 is formed in the recess 238 on the right side in FIG. 3. This slack portion 237a is the beginning of the winding of the coil wire 237.

[0026] 2, coil assembly 230 having the above configuration is coupled so as to be sandwiched between outer yoke 220 and inner yoke 240, and A-phase stator unit 200 is configured with terminal block 235 fitted into notch 222a of outer yoke 220 and notch 241a of inner yoke 240. Similarly, coil assembly 330 is coupled so as to be sandwiched between outer yoke 320 and inner yoke 340, and B-phase stator unit 300 is configured with terminal block 235 fitted into notch 322a of outer yoke 320 and notch 341a of inner yoke 340, as shown in FIG.

[0027] 3. Coil assembly formation procedure The procedure for forming the coil assembly 230 will be described with reference to Figures 5 to 7. In Figure 5, reference numeral 600 denotes a spindle of an automatic winding machine, which is attached to the main body of the automatic winding machine and rotates. As shown in Figure 6, the spindle 600 includes a main body 601 made of a substantially rectangular block, a disk-shaped bobbin holder 602, and a shank portion 603 that is gripped by the main body of the automatic winding machine.

[0028] A base 604 is attached to the top surface of the main body 601 with screws 605. A slack forming pin 606 is attached to the base 604. The slack forming pin 606 has a thick base to ensure rigidity. A recess 604a is formed on one side of the base 604 facing the axial direction, and the terminal block 235 fits into this recess 604a to position it. Note that reference numeral 607 in the figure denotes a pressing member for fixing the bobbin 232 attached to the bobbin receiver 602. The pressing member 607 is moved toward the main body 601 by a drive mechanism (not shown), and works together with the main body 601 to clamp the coil assembly 230 and rotates along with the spindle 600 in this state.

[0029] Next, a procedure for winding the coil wire 237 around the bobbin 232 to form the coil assembly 230 will be described. First, the bobbin 232 is attached to the bobbin receiver 602 manually or by means of a manipulator or the like, and the pressing member 607 is attached to the bobbin receiver 602 to clamp the bobbin 232 between the main body 601 and the pressing member 607. At this time, the small-diameter tip of the slack forming pin 606 is inserted into the recess 238 formed between the terminal pin embedded portions 235a. As shown in Figure 7, a cylindrical curved surface 238a is formed at the corner of the recess 238, and the outer circumferential surface of the slack forming pin 606 is positioned in contact with or very close to the cylindrical curved surface 238a.

[0030] The automatic winding machine has a nozzle that can move three-dimensionally to feed out the coil wire 237, and first winds the coil wire 237 fed from the nozzle around the terminal pin 236. Once the coil wire 237 has been wound up to the terminal pin embedded portion 235a, the nozzle hooks the coil wire 237 around the slack forming pin 606 and guides it to the body of the bobbin 232. In this state, the spindle 600 is positioned as shown in FIG. 5, as viewed from the right side. anti The spindle 600 rotates clockwise, winding the coil wire 237 onto the bobbin 232. At this time, tension acts on the coil wire 237, causing bending stress on the slack forming pin 606, but the cylindrical curved surface 238a of the recess 238 supports the slack forming pin 606, suppressing or preventing deformation. While winding the coil wire 237, the nozzle moves axially to align the coil wire 237. When winding of the coil wire 237 is complete, the spindle 600 stops, and the nozzle feeds out the coil wire 237, which is the last part of the winding, and entangles it around the other terminal pin 236.

[0031] Once the winding of the coil wire 237 is complete, the nozzle cuts the coil wire 237. Then, the presser member 607 is retracted and removed from the bobbin receiver 602, and the coil assembly 230 around which the coil wire 237 is wound is removed from the spindle 600 manually or by means of a manipulator 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, leaving a slack portion 237a in the recess 238.

[0032] In the coil assembly 230 configured as described above, the slack 237a can be formed in the coil wire 237 by a simple operation of inserting the slack forming pin 606 into the recess 238 of the terminal block 235, winding the coil wire 237 around the bobbin 232, and then removing the slack forming pin 606 after the winding. Furthermore, because the slack 237a is present within the recess 238, problems such as the slack 237a moving wildly due to centrifugal force and interfering with the winding can be prevented when the bobbin 232 is mounted on the spindle 600 of an automatic winding machine and the coil wire 237 is wound thereon can be prevented. Furthermore, when the coil wire 237 is wound around the bobbin 232, the slack 237a is located within the recess 238 and does not protrude beyond the inner surface of the flange portion 234, preventing the slack 237a from getting caught.

[0033] In particular, in the above embodiment, slack portion 237a has a shape that follows the outer periphery of slack forming pin 606 inserted into recess 238. Since slack forming pin 606 has a circular cross section, slack portion 237a has a curved shape, making coil wire 237 less likely to break even when tension is applied to it.

[0034] In the above embodiment, coil wire 237 is wound from the longitudinal middle portion of terminal pin 236 to terminal pin embedded portion 235a. Because coil wire 237 is provided with an insulating coating, the wound portion is soldered to establish electrical continuity with terminal pin 236. When soldering the wound portion of the terminal pin by a dip method, a jet method, or the like, if loose portion 237a protrudes beyond the surface of terminal pin embedded portion 235a, there is a risk that solder will adhere to loose portion 237a. However, because loose portion 237a is located within recess 238, it does not protrude beyond the surface of terminal pin embedded portion 235a, and therefore it is possible to prevent solder from adhering to loose portion 237a.

[0035] 4. Example of changes The above embodiment is applied to a unifilar winding (bipolar drive) with two terminal pins 236 and one coil wire 237. The present invention can also be applied to a bifilar winding (unipolar drive) with three terminal pins 236 and two coil wires 237. In this case, the terminal pin 236 is press-fitted into the terminal pin press-fitting hole 235b of the central terminal pin embedding portion 235a shown in FIG. 7, and the coil wire 237 starts to be wound from this terminal pin 236 as well. Accordingly, in this case as well, the coil wire 237 is fed from each of two nozzles provided on an automatic winding machine (not shown), and the winding start portion is entangled around the terminal pin 236 on one end and the terminal pin 236 embedded in the central terminal pin embedding portion 235a. After that, each coil wire 237 is hung on the corresponding slack-forming pin 606 inserted in the recess 238 and wound around the bobbin 232 by a predetermined number of turns. After winding the coil wire 237, each nozzle winds the coil wire 237 at the end around the central terminal pin 236 and the other end terminal pin 236. In this way, the slack portions 237a formed at the start of each winding are located within the recesses 238.

[0036] In the above embodiment, two slack forming pins 606 are attached to base 604. This is because base 604 is provided with slack forming pins 606 for forming slack portion 237a in coil wire 237 at the start of winding, making it possible to use both unifilare winding and bifilar winding. Note that base 604 only needs to be provided with slack forming pins 606 for forming slack portion 237a in coil wire 237 at the start of winding, and it goes without saying that base 604 may be provided with pins 606 dedicated to unifilare winding and bifilar winding, respectively.

[0037] In the above embodiment, multiple terminal pin embedded portions 235a are provided in terminal block 235, but multiple terminal blocks (terminal pin embedded portions) can be formed spaced apart from each other in flange portion 234, and the spaces between the terminal blocks can be used as recesses. In this embodiment, too, slack forming pin 606 can be inserted into the recesses to form slack portions 237a in coil wire 237, as in the above embodiment.

[0038] In the above embodiment, the slack portion 237a is formed when the coil wire 237 starts to be wound around the bobbin 232, but if necessary, the slack portion 237a can also be formed when the winding ends. In this case, the slack forming pin 606 is disposed in the left corner of the recess 238 facing the spindle 600.

[0039] The present invention is not limited to the claw-pole type two-phase stepping motor as in the above embodiment, but can be applied to any stepping motor such as a hybrid type stepping motor. [Industrial Applicability]

[0040] The present invention can be applied to the technical field of stepping motors. [Explanation of symbols]

[0041] 100...Stepping motor, 200...A-phase stator unit, 210...Front plate, 211...Opening, 220...Outer yoke, 221...Annular portion, 222...Outer cylinder portion, 222a...Notched portion, 223...Pole tooth, 230...Coil assembly, 231...Coil, 232...Bobbin, 233...Flange portion, 234...Flange portion, 235...Terminal block, 235a...Terminal pin embedding portion, 235b...Terminal pin press-fit hole, 236...Terminal pin, 237...Coil wire, 237a...Slack portion, 238...Recess, 240...Inner yoke, 241... Circular ring portion, 241a...notch portion, 243...pole tooth, 250...bearing, 260...bearing, 300...B-phase stator unit, 310...end plate, 311...opening, 320...outer yoke, 322a...notch portion, 330...coil assembly, 340...inner yoke, 341a...notch portion, 400...rotor, 401...shaft, 500...stator, 600...spindle, 601...main body, 602...bobbin holder, 603...shank portion, 604...base, 604a...recess, 605...screw, 606...slack forming pin, 607...pressing member.

Claims

1. a bobbin having flanges at both ends; a terminal block provided on one of the flange portions; a plurality of terminal pin embedding portions provided on the terminal block; a terminal pin embedded in the terminal pin embedding portion and extending radially outward from the flange portion; a coil having an end portion of a coil wire wound around the terminal pin and wound around the bobbin, a recessed portion that is recessed in the radial direction of the bobbin and penetrates the bobbin in the axial direction, between the terminal pin embedded portions of the terminal block; 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 loosened portion of the coil assembly is loosened in a direction in which the terminal pin extends.

2. 2. The coil assembly according to claim 1, wherein the coil wire is wound from the terminal pin to the terminal block.

3. a stator; a rotor rotatably supported on the inner circumferential side of the stator, 3. A stepping motor, wherein the stator comprises an outer yoke and an inner yoke mounted to sandwich the coil assembly according to claim 1 or 2.

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