JP2014204590A - Stepping motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stepping motor in which degradation of performance can be prevented by preventing a yoke from being deformed by the injection molding pressure during insert molding, thereby making the driving sound quieter.SOLUTION: Molten synthetic resin is injected from each gate 23A3, 23B3, 24A3, 24B3, and a bobbin 28 is molded integrally with a yoke 22 by insert molding. Since each protrusion 26A1, 26B1, 26A2, 26B2 bears each pole tooth 23B2, 23A2, 24B2, 24A2(the tip thereof) from the outside, the synthetic resin can be prevented from flowing between each pole tooth 23A2, 23B2, 24A2, 24B2 and a horizontal direction positioning device 5 by the injection molding pressure during insert molding.

Description

  The present invention relates to a stepping motor. More specifically, the present invention relates to a technique for preventing deformation of a yoke when the yoke is integrated with a bobbin by insert molding.

  In recent years, stepping motors have been required to operate quietly. Insertion molding is performed using a yoke that generates electromagnetic noise as an insert, and the yoke and bobbin are integrated to suppress vibrations of the yoke, resulting in quieter operation. Tend to do.

JP 2008-236931 A

  However, in the stepping motor as shown in Patent Document 1, the yoke is deformed by the injection molding pressure at the time of insert molding, and at the time of molding disposed at the yoke pole teeth (claw pole) and the yoke central portion. As a result, synthetic resin flows in between the horizontal positioning device and burr is generated, and sometimes the burr comes into contact with the rotor, making it difficult to rotate the motor or generating a louder sound. .

  Therefore, an object of the present invention is to provide a stepping motor that can prevent the yoke from being deformed by the injection molding pressure at the time of insert molding, make the operation sound quieter, and prevent the performance from deteriorating.

For this reason, the first invention is a rotor in which a magnet is integrated around a motor shaft,
A plurality of pole teeth each standing up from a ring-shaped annular portion are provided at the inner end of the annular portion via cut portions at predetermined intervals, and are combined so that the pole teeth are alternately meshed in a non-contact manner. A stator composed of a yoke in which a plurality of upper and lower pairs are stacked and a bobbin around which a coil is wound;
In a stepping motor that is integrated by insert molding with a terminal block that is arranged on the outer periphery of the annular portion and attaches a plurality of terminals for energizing the coil,
A support portion for supporting the pole teeth from the outside at the time of the insert molding is formed at a central portion of each inner end portion of the annular portion forming each cut portion.

According to a second aspect of the present invention, a rotor in which a magnet is integrated around a motor shaft;
A plurality of pole teeth each standing up from a ring-shaped annular portion are provided at the inner end of the annular portion via cut portions at predetermined intervals, and are combined so that the pole teeth are alternately meshed in a non-contact manner. A stator composed of a yoke in which a plurality of upper and lower pairs are stacked and a bobbin around which a coil is wound;
In a stepping motor that is integrated by insert molding with a terminal block that is arranged on the outer periphery of the annular portion and attaches a plurality of terminals for energizing the coil,
A projecting portion projecting inward is formed at the center of each inner end portion of the annular portion forming each cut portion so as to support the pole teeth from the outside during the insert molding. .

A third invention is a rotor in which a magnet is integrated around a motor shaft;
A plurality of pole teeth each standing up from a ring-shaped annular portion are provided at the inner end of the annular portion via cut portions at predetermined intervals, and are combined so that the pole teeth are alternately meshed in a non-contact manner. A stator composed of a yoke in which a plurality of upper and lower pairs are stacked and a bobbin around which a coil is wound;
In a stepping motor that is integrated by insert molding with a terminal block that is arranged on the outer periphery of the annular portion and attaches a plurality of terminals for energizing the coil,
A support piece for supporting the pole teeth from the outside at the time of the insert molding is formed upright at the center of each inner end portion of the annular portion forming each cut portion.

  According to the present invention, it is possible to provide a stepping motor that can prevent the yoke from being deformed by the injection molding pressure at the time of insert molding, make the operation sound quieter, and prevent the performance from deteriorating.

It is a longitudinal cross-sectional view which passes along A terminal of a stepping motor. It is a disassembled perspective view of a yoke. It is a perspective view of the state where what combined the upper yoke and the lower yoke was piled up on two steps up and down. It is a cross-sectional plan view of the uppermost annular portion 23A1 in a state where the yoke and the bobbin are integrated. It is a perspective view of the state which integrated the yoke and the bobbin. It is a principal part longitudinal cross-sectional view which passes along B terminal of a stepping motor. It is a top view of the state before making each terminal by a press-fit cylinder press-fit into a terminal block. It is a top view in the state where each terminal by the press-fitting cylinder was partially press-fitted into the terminal block. It is a principal part longitudinal cross-sectional view of the state which made the A terminal partially press-fit in the terminal block. It is a principal part longitudinal cross-sectional view of the state which made the B terminal partially press-fit in the terminal block. It is a principal part top view in the state where each terminal by the press-fitting cylinder was partially press-fitted into the terminal block. FIG. 4 is a perspective view of a state in which each terminal is partially press-fitted into the terminal block (however, the press-fitting cylinder is omitted). It is a principal part top view in the state where a magnet wire was wound on a bobbin in the state where a part of each terminal by a press-fitting cylinder was press-fitted into a terminal block. It is a perspective view (however, a press-fit cylinder is abbreviate | omitted) of the state which wound the magnet wire to the bobbin in the state which made each terminal by a press-fit cylinder press-fit to a terminal block. It is a principal part top view in the state where each terminal by the press-fitting cylinder was press-fitted into the terminal block. It is a principal part longitudinal cross-sectional view of the state which made the A terminal press-fit in a terminal block. It is a principal part longitudinal cross-sectional view of the state which made the B terminal partially press-fit in the terminal block. It is a principal part top view of the state in which the magnet wire was partially loosened in a state where each terminal by the press-fitting cylinder was press-fitted into the terminal block. It is a side view of a stepping motor. It is AA sectional drawing of FIG. It is a state figure before mold-clamping with an upper mold and a lower mold. It is a state figure after mold-clamping and forming. It is a disassembled perspective view of the yoke of 2nd Embodiment. It is a perspective view of the state where what combined the upper yoke and lower yoke of a 2nd embodiment was piled up in two steps.

  Hereinafter, an embodiment of a stepping motor 10 according to the present invention will be described with reference to FIG. Reference numeral 11 denotes a stainless steel motor shaft serving as a rod-shaped output shaft, and a magnet 12 is integrally fixed around the motor shaft 11. That is, the magnet 12 is manufactured by mixing magnetic powder in polar anisotropic synthetic resin and integrally molding the motor shaft 11 while orienting the magnetic field. The magnet 12 having a large number of magnetic poles magnetized in the circumferential direction and the motor shaft 11 constitute a rotor and rotate. The motor shaft 11 transmits an attractive force and a repulsive force generated from the magnet 29 and the magnet 12 for exciting the pole teeth of the yoke, which will be described later, to the outside.

  That is, in the case of unipolar driving, the common line is fixed to plus or minus, and other terminals are switched to pass current through the coil 29. In the case of bipolar drive, the current direction is switched by always switching between terminals. When a current is periodically passed through the coil 29, a magnetic field is alternately generated in the yoke 22 (described later) from the south pole to the north pole, and the direction of the current flowing through the coil 29 is switched to thereby attract the magnet 12. A rotating force is generated by the repulsive force, and the stepping motor 10 generates a force using the generated rotating force via the motor shaft 11 as a torque.

  Reference numeral 13 denotes a cup-shaped steel case having an open bottom surface, and an upper bearing 14 for rotatably supporting the motor shaft 11 is press-fitted into the recess 13A, and the motor shaft 11 is formed on the bottom surface forming the upper surface recess 13A. An insertion hole 13B for insertion is opened. An opening 13 </ b> C is formed in the side surface of the case 13.

  Reference numeral 15 denotes a cover that covers the lower surface opening of the case 13, and a lower bearing 16 that rotatably supports the motor shaft 11 is press-fitted into the recess 15A, and the motor shaft 11 is inserted into an upper surface that forms the recess 15A. An insertion hole 15B is formed. The cover 15 fitted so as to cover the lower surface opening of the case 13 is fixed, and the case 13 and the cover 15 constitute a motor case.

  The upper bearing 13 and the lower bearing 16 are made by sintering copper or iron powder, and support the motor shaft 11 inserted by impregnating oil in pores (porous) between the powders. The motor shaft 11 is supported so that it can rotate smoothly.

  17 and 19 are a stainless steel spring washer 18 disposed below the surface of the case 13 forming the recess 13 and the upper surface of the magnet 12, the surface of the cover 15 forming the recess 15A, and the surface of the cover 15. A disc-shaped thrust washer in which the motor shaft 11 is rotatably fitted between the lower surface of the magnet 12 and the thrust washer 17 is made of a synthetic resin material having wear resistance and excellent slidability. In addition, the rotor (motor shaft 11) is smoothly rotated, and generation of sound, heat generation, wear, and the like due to contact between metals are suppressed. The amount of thrust can be adjusted by adjusting the thickness.

  The spring washer 18 has a disk shape in which the motor shaft 11 is rotatably fitted and swells upward toward the center portion, and the thrust washer 17 is formed on the bottom surface forming the recess 13A of the case 13. The rotation of the rotor is stabilized by pressing and urging with an elastic force.

  2 and 3, a magnetic iron-based metal yoke 22 has a pair of first yokes of a first upper yoke 23A and a first lower yoke 23B, a second upper yoke 24A and a second yoke. 2 A pair of second yokes with the lower yoke 24B are vertically stacked to form two stages, but three or more stages may be stacked. The first upper yoke 23A and the second lower yoke 24B are the same, and the first lower yoke 23B and the second upper yoke 24A are the same, and are disposed in the opposite vertical directions.

  More specifically, in the first upper yoke 23A, an injection port 23A3 for injecting a molten synthetic resin is opened at a predetermined interval in the plane portion, and a positioning groove 23A4 at the time of injection molding is formed in the outer edge portion. A ring-shaped annular portion (horizontal plane) 23A1 and a cut-out portion 23AS are provided at predetermined intervals on the inner end of the annular portion 23A1. For example, five side views are generally triangular. And a claw pole 23A2 having a rounded top apex angle. In the first lower yoke 23B, an injection port 23B3 for injecting a molten synthetic resin is opened at a predetermined interval in a flat surface portion thereof, and a positioning groove 23B4 at the time of injection molding on an outer peripheral portion (outer peripheral edge portion) and a later-described A ring-shaped annular portion (horizontal plane) 23B1 in which a formation groove 23B5 for forming the terminal block 30 to be formed is formed, and cut portions 23BS are provided at predetermined intervals on the inner end portion of the upper surface 23B1. For example, there are five pole teeth 23B2 standing upright, for example, having a triangular shape in a side view and a rounded apex angle.

  In addition, the second upper yoke 24A has injection ports 24A3 for injecting molten synthetic resin at predetermined intervals in the plane portion, and positioning grooves 24A4 at the time of injection molding and the terminal block 30 at the outer edge portion. A ring-shaped annular portion (horizontal plane) 24A1 in which a formation groove 24A5 for forming a ring is formed, and a cut-out portion 24AS are provided at predetermined intervals on the inner end portion of the annular portion 24A1 to stand and hang down. For example, five pole teeth 24A2 having a substantially triangular shape in a side view and a rounded apex angle are provided. The second lower yoke 24B is a ring in plan view in which an injection port 24B3 for injecting a molten synthetic resin is opened at a predetermined interval in the plane portion and a positioning groove 24A4 at the time of injection molding is formed in the outer edge portion. A circular ring portion (horizontal plane) 24B1 and a cut-out portion 24BS standing at predetermined intervals on the inner end portion of the circular ring portion 24B1, for example, five side views are generally triangular, And a pole tooth 24B2 having a rounded apex angle.

  The pole teeth 23A2, 23B2, 24A2, 24B2 are formed upright at the inner ends of the annular portions 23A1, 23B1, 24A1, 24B1 so as to be orthogonal to the annular portions 23A1, 23B1, 24A1, 24B1. .

  In this case, as shown in FIG. 3, the pole teeth 23A2 of the first upper yoke 23A and the pole teeth 23B2 of the first lower yoke 23B, and the pole teeth 24A2 of the second upper yoke 24A and the second lower yoke The pole teeth 24B2 of the yoke 24B are used in combination so that they are alternately meshed with each other without contact. The total number of teeth is 20 in this embodiment. In this embodiment, the number of teeth is 20 and the angle of movement per pulse is determined by the number of teeth, so the rotation is 18 degrees per pulse. And it is used in the range of 16 to 48 sheets, and if it is 16, it rotates 22.5 degrees per pulse, and if it is 48 sheets, it rotates 7.5 degrees per pulse.

  As described above, the inner end portion of the annular portion 23A1 of the first upper yoke 23A is cut at a predetermined interval so that the cut portion 23AS becomes the inner end of the annular portion 23B1 of the first lower yoke 23B. Are cut at predetermined intervals to cut the cut portion 23BS, and the inner end of the annular portion 24A1 of the second upper yoke 24A is cut at predetermined intervals to cut the cut portion 24AS to the second lower yoke 24B. The inner end of the annular portion 24B1 is excised at predetermined intervals to form the excised portion 24BS. The excised portions 23AS, 23BS, 24AS, and 24BS are respectively connected to the polar teeth 23A2, 23B2, 24A2, The depth dimension (depth) is cut larger than the thickness of 24B2.

  In this case, in the center part of each inner end of the annular parts 23A1, 23B1, 24A1, 24B1 forming the cut parts 23AS, 23BS, 24AS, 24BS, Certain protrusions 26A1, 26B1, 26A2, and 26B2 are formed. In addition, the height of each projection 26A1, 26B1, 26A2, 26B2 from the position where each projection 26A1, 26B1, 26A2, 26B2 is not formed and the thickness of each of the pole teeth 23A2, 23B2, 24A2, 24B2 The total is the same size as the depth dimensions of the cutouts 23AS, 23BS, 24AS, and 24BS where the protrusions 26A1, 26B1, 26A2, and 26B2 are not formed.

  Reference numeral 28 denotes a bobbin integrally formed by inserting the yoke 22 as an insert and molding it by injection molding of an insulating synthetic resin, and fixes the yoke 22. In this case, first, before the insert molding is performed by the insert molding apparatus 1 shown in FIG. 21, in the mold open state, the second portion with the annular portion 24B1 down and the pole teeth 24B2 up. The lower yoke 24B is fitted in and inserted into a columnar horizontal positioning portion 2A whose central space portion is erected upward at the center of the upper surface of the lower mold 2, and is formed on the upper surface of the lower mold 2. The angle positioning portion 2B erected upward is fitted into the positioning groove 24B4, and the second lower yoke 24B is set on the upper surface of the lower mold 2.

  Next, the left and right horizontal slide lower molds 3A1 and 3B1 in FIG. 21 are moved toward the horizontal positioning portion 2A, and the second lower slides are inserted into the grooves formed on the lower surfaces of the horizontal slide lower molds 3A1 and 3B1. The second lower yoke 24B is positioned by inserting the annular portion 24B of the yoke 24B. That is, the annular portion 24B of the second lower yoke 24B is inserted into the space between the lower surface of the horizontal slide lower molds 3A1 and 3B1 and the upper surface of the lower mold 2 forming the groove, and is positioned. Further, when the horizontal slide lower molds 3A1 and 3B1 are moved toward the horizontal positioning portion 2A, the first vertical positioning members provided inwardly on the horizontal slide lower molds 3A1 and 3B1. (Not shown) presses the annular portion 24B1 of the second lower yoke 24B against the lower mold 2 from above to position and regulate the positioning of the second lower yoke 24B in the vertical direction (height direction). And supporting the lower surface of the annular portion 24A1 of the second upper yoke 24A by means of a second vertical positioning member (not shown) provided inwardly on the lateral slide lower dies 3A1 and 3B1. Is possible.

  Next, the angular positioning of the second upper yoke 24A with the annular portion 24A1 on the top and the pole teeth 24A2 on the bottom so that the central space portion is fitted into the horizontal positioning portion 2A. The portion 2B is fitted into the positioning groove 24A4. In this case, the lower surface of the annular portion 24A1 of the second upper yoke 24A is supported by the second vertical positioning member.

  Further, above the second upper yoke 24A, the central space portion of the first lower yoke 23B with the annular portion 23B1 on the lower side and the pole teeth 23B2 on the upper side is positioned as the horizontal positioning portion 2A. The angle positioning portion 2B is fitted into the positioning groove 23B4 so as to be inserted. In this case, the annular portion 24A1 of the second upper yoke 24A and the annular portion 24B1 of the first lower yoke 23B are back to back.

  In this state, when the horizontal slide upper molds 3A2 and 3B2 are moved toward the horizontal positioning portion 2A, the horizontal slide lower molds 3A1 and 3B1 are provided inwardly with respect to each other. 3. A vertical positioning member (not shown) regulates positioning of the annular portion 23B1 of the first lower yoke 23B from above, and a fourth vertical positioning member (not shown) of the first upper yoke 23A. The lower surface of the annular portion 23A1 can be supported.

  Next, the central space of the first upper yoke 23A with the annular portion 24A1 up and the pole teeth 24A2 down is inserted into the horizontal positioning portion 2A, and the angular positioning is performed. The portion 2B is fitted into the positioning groove 23A4. In this case, the lower surface of the annular portion 23A1 of the first upper yoke 23A is supported by the fourth vertical positioning member.

  Accordingly, the pole teeth 23A2 of the first upper yoke 23A and the pole teeth 23B2 of the first lower yoke 23B, and the pole teeth 24A2 of the second upper yoke 24A and the pole teeth 24B2 of the second lower yoke 24B are formed. A pair of first yokes including a first upper yoke 23A and a first lower yoke 23B, a second upper yoke 24A, 2 A pair of second yokes with the lower yoke 24B are vertically stacked to form a two-stage stacked state, and the angle positioning portions 2B are fitted into the positioning grooves 23A4, 23B4, 24A4, 24B4, respectively in the horizontal direction and the rotational direction. Positioning is possible.

Then, when the terminal part slide mold 4 is moved in the horizontal direction (right direction in FIG. 21) and the upper mold 5 is moved downward to perform the mold clamping, the cavity S is formed.
When the clamping is performed, the pole teeth 24A2 of the second upper yoke 24A and the second lower yoke are disposed between the pole teeth 23A2 of the first upper yoke 23A and the pole teeth 23B2 of the first lower yoke 23B. Positioning is performed in such a manner that there is a gap between the pole teeth 24B2 of the 24B, that is, in a non-contacting state. Instead of moving the upper mold 5 downward and clamping it like an abnormality, the lower mold 2 may be moved upward and clamped.

  In this state, an injection passage 5A is formed in the upper mold 5, and the synthetic resin melted from the injection ports 23A3, 23B3, 24A3, and 24B3 through the injection passage 5A communicating with an injection nozzle (not shown). It is injected into the cavity S, and a bobbin 28 is formed integrally with the yoke 22 (see FIGS. 4 and 22). Therefore, between the pole teeth 23A2 of the first upper yoke 23A and the pole teeth 23B2 of the first lower yoke 23B, the pole teeth 24A2 of the second upper yoke 24A and the pole teeth 24B2 of the second lower yoke 24B. The gaps between them are filled and connected with synthetic resin by this insert molding, and the inlets 23A3, 23B3, 24A3, and 24B3 are also filled. After the insert molding, the mold is opened and the bobbin 28 integrated with the yoke 22 is taken out from the cavity S. When the mold is opened, the ejector pin 8 is raised to release the molded product from the mold. The molded product is peeled off from the lower mold 2 and can be easily taken out from the cavity S.

  The bobbin 28 has a part of the annular part 23B1 in which the formation groove 25B5 of the first lower yoke 23B is formed and an annular part in which the formation groove 24A5 of the second upper yoke 24A is formed. The terminal block 30 is formed so as to cover a part of 24A1 and project outward (see FIG. 5). It should be noted that the notched portion 28A having no synthetic resin is formed on the lower surface of the first upper yoke 23A, the upper surface of the first lower yoke 23B, the lower surface of the second upper yoke 24A, and the upper surface of the second lower yoke 24B. The first to fourth vertical positioning members are formed (see FIG. 5).

  In this case, at the time of this injection molding, the projections 26A1, 26B1, 26A2, and 26B2 support the pole teeth 23B2, 23A2, 24B2, and 24A2 (tips thereof) from the outside, so that injection molding at the time of insert molding is performed. The synthetic resin can be prevented from flowing between the respective pole teeth 23A2, 23B2, 24A2, 24B2 of the yoke 22 and the horizontal positioning portion 2A by the pressure, and the yoke can be prevented from being deformed.

  Therefore, in the past, the synthetic resin flowed in and burr was generated, and this burr contacted the rotor (magnet 12), making it difficult to rotate the motor or generating a loud sound. To provide a stepping motor 10 that can prevent the yoke 22 from being deformed by the injection molding pressure at the time of insert molding, make the operation sound quieter, and prevent the performance from deteriorating without disturbing the rotation. it can.

  Reference numeral 29 denotes a multipolar coil made of a magnet wire MW wound around the bobbin 28. The magnet wire MW is usually a copper wire coated with urethane resin or polyamide resin. The bobbin 28 electrically insulates the coil 29 and the yoke 22 from each other.

  As described above, the terminal block 30 is formed on the bobbin 28. The terminal block 30 has insertion grooves 30A into which two terminal pins 31A of a central A terminal 31 are inserted, respectively. Insertion grooves 30B into which the two terminal pins 32A and 32A respectively separated above and below the B terminals 32 and 32 arranged on both sides of the A terminal 31 are formed are formed (see FIGS. 1 and 6). ).

  The A terminal 31 and the B terminals 32 and 32 are energized to the coil 29 through the terminal block 30 and are made of iron or brass and plated with tin or solder gold for solderability and corrosion resistance. Has been. Next, the terminal pins 31A, 32A, 32A of the A terminal 31, B terminals 32, 32 are inserted (press-fitted) into the terminal block 30 and fixed, and the magnet wire MW is wound on the bobbin 28 and the coil is wound. A method for producing the material 29 will be described.

  First, as shown in FIG. 7 showing an apparatus for terminal-treating a magnet wire in a stepping motor, a cylinder body 34A of a press-fit cylinder 34 is fixed on a work table 40, and the yoke 22 is integrated with the cylinder 22A. The bobbin 28 is set on the work table 40. Support members 36A and 36B are fixed to both ends of the two rods 35 of the press-fit cylinder 34, respectively, and the terminal pins of the A terminal 31, B terminals 32 and 32 are attached to the support member 3B6 on the distal end side. A holder 37, which is a press-fitting jig for detachably holding 31C, 32C, and 32C (connected to a power source via a connector), is fixed. Between the two rods 35, there is provided a rod 39 provided with a main stopper 38 for limiting the length of the rod 35 when the rod 35 moves, and the cylinder on the tip side of the rod 39 is further provided. A detachable auxiliary stopper 41 can be disposed on the side surface of the main body 34A.

  First, the bobbin 28 integrated with the yoke 22 is set on the work table 40, and the terminal pin 31C of the A terminal 31 and the terminal pins 32C and 32C of the B terminals 32 and 32 are placed on the holder 37. Install. Next, in a state where the auxiliary stopper 41 is attached to the side surface of the cylinder body 34A, the press-fitting cylinder 34 is operated to push out and move the rod 35. Then, as shown in FIG. 8, the main stopper 38 comes into contact with the sub-stopper 41 and the pushing is restricted, and the terminal pins 31A, 32A, 32A of the A terminal 31, B terminals 32, 32 are It is press-fitted to about half of the insertion grooves 30A and 30B formed in the terminal block 30 (FIGS. 9, 10, 11 and 12).

  Next, in this state, one end of each magnet wire MW is connected to each of the upper and lower terminal pins 32B and 32B of the left B terminal 32 and the upper and lower terminal pins 31B and 31B of the central A terminal 31, for example, 3, The magnet wires MW are wound around the bobbin 28 by a winding machine to form the two upper and lower coils 29 respectively. Then, after the coil 29 is formed, the other end of the magnet wire MW fixed to the left upper and lower terminal pins 32B and 32B is fixed to the center upper and lower terminal pins 31B and 31B, and the center upper and lower terminal pins 32B and 32B. The other end of the magnet wire MW that is fixed to one end of the terminal pins 31B and 31B is fixed to the upper and lower terminal pins 32B and 32B of the right B terminal 32 (see FIGS. 13 and 14). Then, after the end of the winding, each A terminal 31, B terminal 32, 32 and each end of the magnet wire MW entangled with each other are connected by soldering so as to be electrically conductive. Accordingly, both end portions of the magnet wire MW are soldered and fixed to the A terminal 31 and the B terminals 32 and 32, respectively.

  Next, since the main stopper 38 and the sub-stopper 41 are in contact with each other and the extrusion is restricted, when the sub-stopper 41 is removed from the side surface of the cylinder body 34A, the main stopper 38 is An insertion groove in which the terminal pins 31A, 32A, 32A of the A terminal 31, B terminals 32, 32 are formed in the terminal block 30 is brought into a state where the extrusion is restricted by contacting the cylinder body 34A (see FIG. 15). It inserts to the innermost part in 30A, 30B, and 30B, and also press-fits (refer FIG. 16, FIG. 17). In this case, the terminal pins 31 </ b> B, 32 </ b> B, 32 </ b> B of the A terminal 31, B terminals 32, 32 come into contact with the front end of the terminal block 30.

  Therefore, as shown in FIG. 18, a part of the magnet wire MW not wound around the bobbin 28 (between the terminal pins 31B, 32B, 32B of the A terminal 31, B terminals 32, 32 and the bobbin 28). ) Is in a relaxed state, and then the holder 37 is removed from the terminal pin 31C of the A terminal 31 and the terminal pins 32C and 32C of the B terminals 32 and 32 (see FIGS. 19 and 20). For this reason, conventionally, since the magnet wire MW is not slack and is in a tensioned state as in this embodiment, vibration during operation of the stepping motor 10, the A terminal 31, and the B terminals 32, 32. On the other hand, there is a possibility that disconnection may occur due to insertion / removal of a connector for connection to a power source, vibration due to operation of the stepping motor 10 or the like, but such disconnection can be prevented as much as possible.

  Next, a method for assembling the stepping motor 10 will be briefly described below. First, as described above, the yoke 22 and the bobbin 28 are integrally formed by insert molding, and the A terminal 31 and the B terminals 32 and 32 are connected to the terminal block 30 of the bobbin 28 and the magnet wire. The coil 29 is formed by winding the MW. That is, the yoke 22, the bobbin 28, and the coil 29 form a stator.

  On the other hand, as described above, the rotor that has been formed integrally with the motor shaft 11 to produce the magnet 12 is placed in the yoke 22. In this case, the magnet 12 is set as large as possible so as not to contact the yoke 22. Then, a rotor accommodated in the yoke 22 is inserted into the case 13 so that the terminal block 30 is guided outward from the opening 13C on the side surface of the case 13, and the lower surface opening of the case 13 is opened. With the cover 15 being closed, the cover 15 is fixed to the case 13 by appropriate means (see FIGS. 1, 19, and 20).

  Next, a second embodiment of the yoke 22 will be described with reference to FIGS. 23 and 24, but the same or similar structure / function will be achieved unless otherwise specified. First, the difference from the first embodiment is that the annular portion 23A1 that forms the cut portions 23AS, 23BS, 24AS, and 24BS instead of the protrusions 26A1, 26B1, 26A2, and 26B2 of the first embodiment. , 23B1, 24A1, and 24B1, the support pieces 26A3, 26B3, 26A4, and 26B4 that are support portions are formed upright at the center of each inner end portion.

  The lengths of the support pieces 26A3, 26B3, 26A4, and 26B4 in the vertical direction are formed longer than the thicknesses of the annular portions 23A1, 23B1, 24A1, and 24B1. On the other hand, the length of each pole tooth 23A2, 23B2, 24A2, 24B2 of the second embodiment is formed slightly shorter than that of the first embodiment. When the pair of first yokes and the other pair of second yokes are stacked one above the other, the pole teeth 23B2 and the support piece 26A3 are replaced with the pole teeth 23A2 and the support piece 26B3. However, the pole teeth 24A2 and the support pieces 26B4 are so arranged that the pole teeth 24A2 and the support pieces 26B4 partially overlap each other so that the pole teeth 24B2 and the support pieces 26A4 do not collide in the vertical direction. , 24B2 to form the apex angle, the outer portion of the tip is thinly cut to form the overlapping portions 27A1, 27B1, 27A2, and 27B2.

  That is, as described above, when the pair of first yokes and the other pair of second yokes are stacked one on top of the other, the overlapping portions 27A1 of the pole teeth 23A2, 23B2, 24A2, and 24B2 are stacked. 27B1, 27A2, 27B2 and the inner surface of the tip of each support piece 26B3, 26A3, 26B4, 26A4 overlap so that the inner surfaces of all the pole teeth 23A2, 23B2, 24A2, 24B2 are not deformed by the injection pressure. The bearing pieces 26B3, 26A3, 26B4, and 26A4 are supported from the outside.

  Therefore, it is possible to prevent the synthetic resin from flowing between the respective pole teeth 23A2, 23B2, 24A2, 24B2 of the yoke 22 and the horizontal positioning device 5 due to the injection molding pressure at the time of insert molding, and the yoke 22 is deformed. You can avoid it.

  Therefore, in the past, the synthetic resin flowed in and burr was generated, and this burr contacted the rotor (magnet 12), making it difficult to rotate the motor or generating a loud sound. Also in the second embodiment of the yoke 22, as in the first embodiment, the yoke 22 is not deformed by the injection molding pressure at the time of insert molding, the operation sound is made quieter, and the rotation is obstructed. Thus, it is possible to provide the stepping motor 10 that can prevent the performance from deteriorating.

  Although the embodiments of the present invention have been described above, various alternatives, modifications, and variations can be made by those skilled in the art based on the above description. It includes modifications or variations.

10 Stepping motor 11 Motor shaft 12 Magnet 22 Yoke 23A First upper yoke 23B First lower yoke 24A Second upper yoke 24B Second lower yoke 23A1, 23B1, 24A1, 24B1 Ring portions 26A1, 26B1, 26A2, 26B2 Protruding portion 23B2 , 23A2, 24B2, 24A2 Pole teeth 23AS, 23BS, 24AS, 24BS Cutting part 26B3, 26A3, 26B4, 26A4 Bearing piece 28 Bobbin 29 Coil 30 Terminal block

Claims (3)

A rotor with magnets integrated around the motor shaft;
A plurality of pole teeth each standing up from a ring-shaped annular portion are provided at the inner end of the annular portion via cut portions at predetermined intervals, and are combined so that the pole teeth are alternately meshed in a non-contact manner. A stator composed of a yoke in which a plurality of upper and lower pairs are stacked and a bobbin around which a coil is wound;
In a stepping motor that is integrated by insert molding with a terminal block that is arranged on the outer periphery of the annular portion and attaches a plurality of terminals for energizing the coil,
A stepping motor, wherein a support portion for supporting the pole teeth from the outside at the time of the insert molding is formed at a central portion of each inner end portion of the annular portion forming each cut portion. A rotor with magnets integrated around the motor shaft;
A plurality of pole teeth each standing up from a ring-shaped annular portion are provided at the inner end of the annular portion via cut portions at predetermined intervals, and are combined so that the pole teeth are alternately meshed in a non-contact manner. A stator composed of a yoke in which a plurality of upper and lower pairs are stacked and a bobbin around which a coil is wound;
In a stepping motor that is integrated by insert molding with a terminal block that is arranged on the outer periphery of the annular portion and attaches a plurality of terminals for energizing the coil,
A projecting portion projecting inward is formed at the center of each inner end portion of the annular portion forming each cut portion so as to support the pole teeth from the outside during the insert molding. Stepping motor. A rotor with magnets integrated around the motor shaft;
A plurality of pole teeth each standing up from a ring-shaped annular portion are provided at the inner end of the annular portion via cut portions at predetermined intervals, and are combined so that the pole teeth are alternately meshed in a non-contact manner. A stator composed of a yoke in which a plurality of upper and lower pairs are stacked and a bobbin around which a coil is wound;
In a stepping motor that is integrated by insert molding with a terminal block that is arranged on the outer periphery of the annular portion and attaches a plurality of terminals for energizing the coil,
A stepping motor, wherein a support piece for supporting the pole teeth from the outside at the time of the insert molding is formed upright at a central portion of each inner end portion of the annular portion forming each cut portion.

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