JP5049754B2 - Manufacturing method of flat commutator - Google Patents

Description

  The present invention relates to a method of manufacturing a commutator used for an electric motor, a generator, or the like, and more particularly to a method of manufacturing a flat type commutator in which each segment piece is disposed with its sliding contact surface facing the axial direction.

  An electric motor with a brush is provided with a commutator for commutating a direct current supplied from a power source at a predetermined timing and supplying the direct current to the amateur coil. This commutator is provided with metal segment pieces, and these segment pieces are arranged at predetermined intervals in the circumferential direction and fixed to a resin holder portion and insulated from each other. Each segment piece is connected to a coil end of a corresponding amateur coil, and the brush is in sliding contact with the sliding contact surface.

  As such a commutator, a cylindrical one (cylinder type) in which a segment piece is arranged on the outer peripheral surface of a cylindrical holder portion and the brush is brought into sliding contact with the segment piece from the radial direction is often used. However, in an electric power steering, an engine starter, an electric motor or the like used for a fuel pump, a flat commutator (also called a flat commutator or a disk commutator) is used to reduce the size of the apparatus. In such a flat type commutator, the holder portion is formed in a disk shape from a resin material, the segment piece is fixed to one axial end surface of the holder portion with the sliding contact surface facing the axial direction, and the brush is It comes in sliding contact with the segment piece from the direction.

On the other hand, as a manufacturing method of a flat type commutator, for example, as disclosed in Patent Document 1, a plurality of segment pieces are mounted on a metal cartridge, and the resin material is injected in a state where the cartridge is disposed inside a mold. A method is known in which the holder part is resin-molded integrally with the segment piece by molding.
International Publication No. 03/050932 Pamphlet

  However, in the manufacturing method shown in Patent Document 1, since a metal cartridge is used, it is difficult to bring a segment piece, which is also made of metal, into close contact with the cartridge to have a predetermined sealing property, When the resin material is injection-molded, the resin material may invade between the segment piece and the cartridge, and the resin material may remain on the sliding surface or the slit portion between adjacent segment pieces. For this reason, a post-process for removing these residual resins is required, and the man-hours for manufacturing this commutator, that is, the manufacturing cost, has been increased.

  An object of the present invention is to prevent the resin material from adhering to the sliding contact surface of the segment piece during molding of the resin material, and to reduce the manufacturing cost of the flat commutator.

A flat commutator manufacturing method according to the present invention includes a resin holder portion fixed to an amateur shaft, and a plurality of metal segments arranged in a circumferential direction and fixed to the holder portion with a sliding contact surface facing an axial direction. A method of manufacturing a flat commutator provided with a piece, the step of mounting a plurality of the segment pieces in a circumferential direction at predetermined intervals on a resin cartridge provided with a protective surface covering the sliding contact surface And a step of disposing the cartridge on which a plurality of segment pieces are mounted in a molding die, molding the holder portion with a resin material, and a step of removing the cartridge from the segment pieces after the holder portion is molded. possess the door, said the mold facing with a predetermined interval on an outer periphery of the segment piece and the first positioning surface outer periphery of the cartridge abuts And second positioning surface is provided, the resin material is characterized Rukoto filled in the forming die from the axial center portion of the mold.

  The flat commutator manufacturing method of the present invention is characterized in that the cartridge is detached from the segment piece under a state of a glass transition temperature or higher.

  The flat commutator manufacturing method of the present invention is characterized in that the cartridge is formed of a non-reinforced polyamide resin.

  The flat commutator manufacturing method of the present invention is characterized in that the cartridge is made of nylon 66.

  According to the present invention, since the cartridge on which each segment piece is mounted is made of resin, the sliding contact surface of the segment piece is brought into close contact with the protective surface of the cartridge, and the resin is applied to the sliding contact surface when the holder portion is resin-molded. Can be prevented from adhering. This eliminates the need for a post-process for removing the resin adhering to the sliding contact surface, thereby reducing the manufacturing cost of the flat commutator.

  Further, according to the present invention, the cartridge is pressed against the first positioning surface by the pressure of the resin material filled in the mold, and each segment piece is positioned by the second positioning surface. In addition to positioning accurately, the resin piece pressure is used to bring the segment pieces into close contact with the cartridge, ensuring that the resin material enters between the cartridge and the segment pieces or between the cartridge and the inner surface of the mold. Can be prevented.

  Furthermore, according to the present invention, since the cartridge is removed from the segment piece under the state of the glass transition temperature or higher, the cartridge can be easily removed.

  Furthermore, according to the present invention, since the cartridge is formed of non-reinforced polyamide-based resin, when the segment piece is attached to the cartridge, the cartridge is provided with appropriate elasticity and slidability. Installation work can be facilitated. Further, the cartridge can have sufficient heat resistance against the molding of the holder portion.

  Furthermore, according to the present invention, since the cartridge is formed of nylon 66, the cartridge can be easily detached from the segment piece even under a high temperature condition immediately after the holder portion is molded.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a cross-sectional view showing the internal structure of a starter motor used in a motorcycle (motorcycle). The starter motor 11 includes a cylindrical yoke 13 whose ends are closed by covers 12a and 12b. Accommodates an amateur 14 (armature). The amateur 14 is rotatable inside the yoke 13 by the armature shaft 15 being supported by bearings 16a and 16b provided on the covers 12a and 12b, and a plurality of armature cores 17 fixed to the armature shaft 15 are provided. The amateur coil 18 is wound. Further, a flat commutator 21 (hereinafter referred to as a commutator 21) is fixed to the amateur shaft 15 adjacent to the amateur core 17.

  FIG. 2 is a partially cutaway perspective view showing the details of the commutator shown in FIG. 1. This commutator 21 is a so-called flat type (disk type), and is a substantially circular shape whose radial dimension is larger than the axial dimension. It has the holder part 22 formed in plate shape. The holder portion 22 is formed by molding (molding) a resin material such as a thermosetting resin, for example. The holder portion 22 is press-fitted into the armature shaft 15 through a shaft hole 23 formed in the shaft center thereof, and the armature shaft 15 is formed. It is supposed to be fixed to.

  A plurality of segment pieces 24 are fixed to one end face in the axial direction of the holder portion 22 so as to be arranged radially at a predetermined interval in the circumferential direction. These segment pieces 24 are formed of, for example, a metal material such as copper, and the outer shape thereof is substantially a fan shape, and each segment piece 24 is disposed on the holder portion 22 with the sliding contact surface 24a facing in the axial direction. A holder portion 22 is interposed between adjacent segment pieces 24 and a slit 25 is formed on the surface side thereof, and each segment piece 24 is separated by the holder portion 22 and the slit 25 and electrically insulated from each other. Has been. A coil connection portion 24b is provided at one end on the outer peripheral side of each segment piece 24, and a connection groove 24c is formed in each coil connection portion 24b. The coil end of the amateur coil 18 is inserted into the connection groove 24c of the corresponding segment piece 24, and the insertion portion is fusing or the like to be electrically connected to the coil connection portion 24b.

  As shown in FIG. 1, a pair of power supply brushes 26a and 26b are mounted on the cover 12b on the commutator 21 side so as to be movable in parallel to the axis of the armature shaft 15. 26 b is urged by springs 27 a and 27 b, respectively, and is in sliding contact with the sliding contact surface 24 a of each segment piece 24 from the axial direction of the armature shaft 15. Each brush 26a, 26b is connected to a power source (not shown) such as a battery mounted on a vehicle via a starter switch (not shown) or the like, and when the starter switch is operated, a current is supplied from the power source to the brushes 26a, 26b. It is like that. When current is supplied to the brushes 26 a and 26 b, the current is commutated by the brushes 26 a and 26 b and the commutator 21 and supplied to each armature coil 18 at a predetermined timing, thereby the inner surfaces of the armature core 17 and the yoke 13. An electromagnetic force is generated with the magnet 28 fixed to the armature 28, and the armature shaft 15 is rotated in a predetermined direction by the electromagnetic force.

  Next, a method for manufacturing the commutator 21, that is, a method for manufacturing the flat commutator 21 according to an embodiment of the present invention will be described.

  FIG. 3 is a process diagram showing the manufacturing process of the commutator shown in FIG. 2, and the commutator 21 is manufactured through the processes P1 to P6 shown in this process chart. The manufacturing method of the commutator 21 by these processes P1 to P6 will be briefly described. First, a plurality of segment pieces 24 are formed in the segment piece forming process P1, and these segment pieces 24 are formed in a cartridge described later in the cartridge mounting process P2. Installed. Next, an anchor, which will be described later, is processed on the back surface of the slidable contact surface 24a of each segment piece 24 in the anchor formation step P3, and the holder portion 22 is made of resin in a state where the segment piece 24 attached to the cartridge is inserted in the holder portion forming step P4. Molded. When the holder portion 22 is molded, the cartridge is removed from the segment piece 24 in the cartridge removal step P5, and then the connection groove 24c is formed in the coil connection portion 24b in the connection groove formation step P6, thereby completing the commutator 21.

  Next, the detail of each process P1-P6 is demonstrated in order.

  4 is a perspective view schematically showing the segment piece forming step, and FIG. 5 is a perspective view showing details of the segment piece formed by the segment piece forming step shown in FIG.

  The segment piece 24 used for manufacturing the commutator 21 is formed by cutting the base material 31 (theta bar) into a predetermined shape by the segment piece forming step P1. As shown in FIG. 4, as the base material 31, for example, a copper material or the like whose cross-sectional shape is formed in a uniform shape in the axial direction by drawing is used. A plurality of segment pieces 24 made of copper are formed by sequentially cutting along cutting lines indicated by broken lines 4. As shown in FIG. 5, the segment piece 24 formed by the process P1 includes a main body portion 24d having a sliding contact surface 24a, a coil connection portion 24b provided with a step at one end of the main body portion 24d, The other end of the portion 24d is formed in a predetermined shape including a fixing convex portion 24e provided with a step.

  Moreover, the pilot hole 32 which penetrates the coil connection part 24b is previously formed in the coil connection part 24b provided in the end of the segment piece 24 by press work etc., for example. The lower hole 32 facilitates the processing and reduces the burden on the holder portion 22 when the connection groove 24c is processed in the coil connection portion 24b in the connection groove forming step P6 performed after the holder portion 22 is formed. Are previously formed.

  In the present embodiment, the lower hole 32 is formed in the segment piece 24 cut out from the base material 31. However, the present invention is not limited to this, and a plurality of prepared holes are arranged in the base material 31 in the axial direction in advance. 32 may be formed, and the segment piece 24 including the prepared hole 32 may be cut out from the base material 31.

  When the plurality of segment pieces 24 are manufactured in the segment piece forming step P1, the plurality of segment pieces 24 are then attached to the cartridge in the cartridge attaching step P2.

  6 is a front view showing the configuration of the cartridge, and FIG. 7 is a cross-sectional view taken along the line AA in FIG. FIGS. 8A and 8B are perspective views showing a procedure for attaching the segment pieces to the cartridge. FIG. 9 is a front view showing the cartridge in a state where a plurality of segment pieces are attached.

  The cartridge 33 used in the cartridge mounting process P2 is made of resin, and the cartridge 33 includes an annular substrate portion 34. An outer peripheral wall 35 is provided integrally with the substrate portion 34 on the outer periphery of the substrate portion 34, and a plurality of partition walls 36 for forming slits 25 between the segment pieces 24 on the substrate portion 34. Are provided integrally. These partition walls 36 are arranged radially on the substrate portion 34, and one end thereof is connected to the inner surface of the outer peripheral wall 35.

  As shown in FIG. 7, each partition wall 36 has a top surface parallel to the substrate portion 34 and from the substrate portion 34 in a predetermined range from the distal end portion to the base end portion connected to the outer peripheral wall 35. The wall is formed with a constant height. On the other hand, an inclined surface 36a is formed on the base end side of each partition wall 36 as an inclined portion that is inclined in a direction in which the height dimension from the substrate portion 34 gradually increases as the outer peripheral wall 35 is approached. The height of the inclined surface 36a from the substrate portion 34 is higher than that of the tip portion.

  Further, on both side surfaces of the base end portion of each partition wall 36, convex portions 37 for holding the segment piece 24 attached to the cartridge 33 on the cartridge 33 are provided. These convex portions 37 protrude in the circumferential direction along the outer peripheral wall 35 from the side surface of the partition wall 36, and the interval between the adjacent partition walls 36 is narrowed by these convex portions 37.

  The surfaces defined by the adjacent partition walls 36 and the outer peripheral wall 35 on the substrate portion 34 are protective surfaces 38 for covering the sliding contact surfaces 24a of the segment pieces 24, that is, on the substrate portion 34 of the cartridge 33. A plurality of protective surfaces 38 corresponding to the number of segment pieces 24 are formed side by side in the circumferential direction. Then, as shown in FIGS. 8A and 8B, each segment piece 24 abuts the sliding contact surface 24a against the protective surface 38 and is adjacent on both sides thereof with the coil connection portion 24b as the outer peripheral side. The cartridge 33 is mounted so as to be inserted between the partition walls 36.

  At this time, the convex portions 37 provided on each partition wall 36 are crushed and elastically deformed on both side portions of the segment piece 24, and the segment piece 24 is held by the cartridge 33 by the elastic force.

  As described above, in this method of manufacturing the commutator 21, the convex portions 37 projecting in the circumferential direction are provided on both side surfaces of each partition wall 36 of the resin cartridge 33, and the cartridges 33 are crushed against the convex portions 37. The segment piece 24 can be held in the cartridge 33 by the elastic force of the convex portion 37. Accordingly, the segment piece 24 can be prevented from being detached from the cartridge 33 during movement between the processes, and the occurrence of defective products due to a missing piece of the segment piece 24 can be prevented.

  By sequentially inserting a plurality of segment pieces 24 between the partition walls 36, each segment piece 24 has a state in which its sliding contact surface 24a is covered with a protective surface 38 of the cartridge 33, as shown in FIG. Thus, the cartridges 33 are mounted side by side with an interval corresponding to the partition wall 36 in the circumferential direction. Since the distal end portion on the inner peripheral side of each segment piece 24 mounted on the cartridge 33, that is, the fixing convex portion 24e is not restrained by the cartridge 33, each segment piece 24 elastically deforms each partition wall 36, thereby It can be moved slightly.

  Here, the cartridge 33 is formed of a non-reinforced polyamide-based resin called nylon 66 (PA66). When the temperature exceeds a predetermined glass transition temperature (about 50 ° C.), the glass transition occurs and the rigidity and viscosity are lowered. It changes to the rubber state. In the holder part molding step P4 described later, the cartridge 33 is heated to a glass transition temperature or higher by the heat of the heated resin material, thereby increasing the degree of adhesion between the cartridge 33 and the segment piece 24, and the cartridge 33 and the segment. Intrusion of the resin material from between the pieces 24 is prevented.

  When the plurality of segment pieces 24 are attached to the cartridge 33 in the cartridge attachment step P2, an anchor is processed and formed on each segment piece 24 in the anchor formation step P3.

  FIG. 10 is a cross-sectional view showing a processed state of the anchor by the anchor forming die, and FIG. 11 is a perspective view showing details of a segment piece on which the anchor is formed.

  As shown in FIG. 10, the anchor forming die 41 has an upper die 42 and a lower die 43, and the cartridge 33 with the segment piece 24 mounted thereon is disposed on the lower die 43. On the other hand, the upper die 42 is provided with a cylindrical stripper 44, and a punch holder 46 is provided above the stripper 44 via a spring 45. A punch 47 is attached to the punch holder 46 downward. The punch 47 is disposed inside the stripper 44 and supported by the stripper 44 so as to be relatively movable in the axial direction. A nail sharpening portion 47 a is formed at the tip of the punch 47. The claw shaving portion 47a is formed in a taper shape whose inner peripheral side is increased in diameter upward, and is opposed to a portion closer to the inner diameter side of the coil connection portion 24b of each segment piece 24 arranged in the lower mold 43. It has become.

  When the punch holder 46 is pushed downward by a press device (not shown), the coil connecting portion 24b is sandwiched between the stripper 44 and the lower mold 43, and each segment piece 24 is held at a predetermined position. When the punch holder 46 is further pushed down in this state, the punch 47 is lowered and the claw shaving portion 47a comes into contact with a portion closer to the inner diameter side of the coil connecting portion 24b. When the punch holder 46 further lowers the stroke of the thickness dimension of the coil connection portion 24b, the claw shaving portion 47a bites into the segment piece 24, and as shown in FIG. 11, the inside of the coil connection portion 24b of each segment piece 24 An anchor 48 is formed on the circumferential side. At this time, the anchor 48 is formed so as to protrude toward the inner peripheral side along the tapered shape of the nail shaving portion 47a.

  When the anchor 48 is formed by such an anchor forming die 41, each segment piece 24 is pushed downward by the punch 47, so that each segment piece 24 is arranged on the lower die 43 by the pressing force. The cartridge 33 is strongly pressed. Thereby, the convex portion 37 of the cartridge 33 can be sufficiently elastically deformed so that the sliding contact surface 24 a of each segment piece 24 can be brought into close contact with the protective surface 38 of the cartridge 33.

  When the anchor 48 is formed on each segment piece 24 in the anchor forming step, the holder portion 22 is then formed by injection molding of a resin material using a molding die in the holder portion forming step P4.

  FIG. 12 is a cross-sectional view showing a processing state of the forming die in the holder part forming step, and FIG. 13 is a cross-sectional view showing an arrangement state of cartridges and segment pieces inside the forming die.

  As shown in FIG. 12, the mold 51 includes an upper mold 52 and a lower mold 53, and a molding chamber 54 for molding the holder portion 22 is formed between the upper mold 52 and the lower mold 53. ing.

  A cartridge housing portion 55 is provided inside the molding chamber 54 of the lower mold 53, and the cartridge 33 with a plurality of segment pieces 24 mounted thereon is arranged in the housing portion 55. As shown in FIG. 13, the cartridge housing portion 55 has a concave shape including an annular support surface 55 a orthogonal to the axial direction of the molding chamber 54 and a first positioning surface 55 b erected on the outer periphery of the support surface 55 a. The cartridge 33 with a plurality of segment pieces 24 mounted thereon has the segment piece 24 as an upper side to bring the substrate portion 34 into contact with the support surface 55a and the outer peripheral wall 35 against the first positioning surface 55b. It is arranged to be in contact with the accommodating portion 55.

  A segment piece support 56 is provided on the outer side of the lower mold 53 above the cartridge accommodating portion 55. As shown in FIG. 13, the segment piece support 56 includes an annular support surface 56a orthogonal to the axial direction of the molding chamber 54 and a second positioning surface 56b erected on the outer periphery of the support surface 56a. When the cartridge 33 with a plurality of segment pieces 24 mounted thereon is arranged in the cartridge accommodating portion 55, the coil connection portion 24b of each segment piece 24 is arranged on the support surface 56a of the segment piece support portion 56 and its The outer periphery faces the second positioning surface 56b with a predetermined interval.

  As shown in FIG. 12, the upper mold 52 of the molding die 51 is provided with a gate 57 so as to open at the axial center portion of the molding chamber 54, and at a predetermined temperature (180 ° C. in the present embodiment). The resin material heated up to is injected into the molding chamber 54 from the gate 57.

  14 (a) to 14 (c) are explanatory views showing a procedure for resin molding of the holder portion by the molding die, respectively. As shown in FIG. 12, the plurality of segment pieces 24 remain in the state where they are mounted on the cartridge 33. When accommodated in the molding chamber 54, as shown in FIG. 14A, the resin material heated to a predetermined temperature (180 ° C.) is injected from the gate 57 into the molding chamber 54. The resin material injected from the gate 57 is filled into the molding chamber 54 from the upper side of the axial center portion of the molding chamber 54 toward the outer peripheral portion thereof.

  As shown in FIG. 14B, when the resin material is filled up to the segment pieces 24, the segment pieces 24 are caused by the pressure of the resin material injected from above the axial center portion of the molding chamber 54. It is pushed toward the lower side in the axial direction and the outer side in the radial direction. At this time, the heat of the resin material is transmitted through the segment piece 24, whereby the cartridge 33 is heated to a temperature higher than the glass transition temperature, causing a glass transition and changing into a rubber shape.

  When each segment piece 24 is pressed downward in the axial direction by the resin pressure, the sliding contact surface 24 a of each segment piece 24 is pressed against the protective surface 38 of the cartridge 33, and the substrate portion 34 of the cartridge 33 is moved to the cartridge housing portion 55. It is pressed against the support surface 55a. Accordingly, the sliding contact surface 24a of the segment piece 24 is in close contact with the protective surface 38 of the cartridge 33 made of rubber, and the substrate portion 34 of the cartridge 33 made of rubber is in close contact with the support surface 55a. Intrusion of the resin material between the cartridge 33 and the cartridge 33 and between the cartridge 33 and the support surface 55a is prevented.

  On the other hand, when each segment piece 24 is pushed radially outward by the resin pressure, as shown in FIG. 14 (c), the cartridge 33 that is rubbery between each segment piece 24 and the first positioning surface 55b. The outer peripheral wall 35 is sandwiched and compressed so as to reduce its thickness. As a result, the segment piece 24 is in close contact with the rubber-like outer peripheral wall 35, and the rubber-like outer peripheral wall 35 is in close contact with the first positioning surface 55 b, so that the segment piece 24 and the cartridge 33 Intrusion of the resin material between the cartridge 33 and the first positioning surface 55b is prevented.

  Further, when each segment piece 24 is pushed radially outward by the resin pressure and the outer peripheral wall 35 is pushed by the segment piece 24 and compressed, each segment piece 24 moves the inside of the molding chamber 54 to the outside in the radial direction. The outer peripheral portion of the coil connection portion 24b comes into contact with the second positioning surface 56b. Thereby, each segment piece 24 is accurately positioned at a predetermined position in the molding chamber 54.

  In this state, the inside of the molding chamber 54 is filled with a resin material, and the holder portion 22 is formed by solidifying the chamber. The holder portion 22 is formed so as to include an anchor 48 provided on the segment piece 24 and a fixing convex portion 24e, whereby each segment piece 24 is fixed to the holder portion 22. Further, by this molding step P4, the resin material enters the lower holes 32 formed in the respective coil connection portions 24b, and the lower holes 32 are filled with the resin material.

  When the holder part 22 is resin-molded, the molded product is taken out from the mold 51, and a shaft hole 23 is formed in the shaft center of the holder part 22 by a cutting process or the like performed as a post process, and the holder part molding step P4 is performed. finish.

  As described above, in the manufacturing method of the commutator 21, the cartridge 33 to which each segment piece 24 is mounted is made of resin. Therefore, the sliding contact surface 24 a of the segment piece 24 is brought into close contact with the protective surface 38 of the cartridge 33 and the sliding is performed. It is possible to prevent the resin from adhering to the contact surface 24a. Thereby, the post process for removing the resin adhering to the sliding contact surface 24a of the segment piece 24 becomes unnecessary, and the manufacturing cost of the commutator 21 can be reduced.

  Further, in the manufacturing method of the commutator 21, the sliding contact surface 24a of each segment piece 24 is brought into close contact with the protective surface 38 of the cartridge 33 by the pressure of the resin material filled in the mold 51, and the cartridge 33 is supported on the support surface. 55a and the first positioning surface 55b are in close contact with each other, so that the resin material can be reliably prevented from entering between the segment piece 24 and the cartridge 33 and between the cartridge 33 and the inner surface of the mold 51. .

  Further, in this method of manufacturing the commutator 21, the outer periphery of each segment piece 24, that is, the coil connection portion 24b is brought into contact with the second positioning surface 56b by the pressure of the resin material filled in the molding die 51. The segment piece 24 can be accurately positioned on the holder portion 22.

  Furthermore, in this method of manufacturing the commutator 21, the convex portions 37 provided on both side surfaces of each partition wall 36 also have a function of improving the sealing performance between the cartridge 33 and each segment piece 24. It is possible to reliably prevent the resin material from entering between the cartridges 33.

  If the holder part 22 is resin-molded in the holder part molding step P4, the cartridge 33 is then removed from each segment piece 24 in the cartridge removal step P5.

  This cartridge removal process P5 is performed before the cartridge 33 that has been heated to a temperature equal to or higher than the glass transition temperature by receiving the heat of the resin material heated in the holder part molding process P4 is cooled to the temperature or lower. That is, the removal work is performed under the condition where the cartridge 33 is at or above the glass transition temperature. As a result, the cartridge 33 can be removed while the glass 33 is changed to a glass and becomes rubbery, so that the operation can be facilitated.

  As described above, in the method for manufacturing the commutator 21, the cartridge 33 is detached from the segment piece 24 under the state of the glass transition temperature or higher, so that the removal work of the cartridge 33 can be facilitated.

  Further, in the manufacturing method of the commutator 21, the cartridge 33 is formed of a polyamide-based resin such as nylon 66, but such a polyamide-based resin has an appropriate adhesive strength to the resin forming the holder portion 22. have. Therefore, even if the resin material enters between the cartridge 33 and the segment piece 24 in the holder part forming step P4, the entered resin material adheres to the cartridge 33 side, and the resin remains on the segment piece 24. Can be prevented.

  In the present embodiment, after the resin molding of the holder portion 22, the cartridge removal step P5 is performed before the cartridge 33 cools below the glass transition temperature. When the cartridge 33 cools below the glass transition temperature after molding, the cartridge removal step P5 may be performed after the cartridge 33 is heated again above the glass transition temperature.

  On the other hand, when the cartridge 33 is removed, the slit 25 is formed between the adjacent segment pieces 24 by the partition wall 36 of the cartridge 33. In the manufacturing method of the commutator 21, the base end portion of each partition wall 36 of the cartridge 33 is formed. Since the inclined surface 36a is formed on the side, a tapered surface 58 is formed on the outer peripheral portion of the holder portion 22 between the adjacent segment pieces 24 as shown in FIG. Thereby, when the cartridge 33 is removed after the holder portion 22 is molded, the corner portion of the holder portion 22 can be prevented from being chipped.

  As described above, in the manufacturing method of the commutator 21, the inclined surface 36a is formed on the base end side of each partition wall 36 of the cartridge 33. Therefore, the outer peripheral portion of the holder portion 22 between the adjacent segment pieces 24 is formed. It forms as the taper surface 58, and when removing the cartridge 33, it can prevent that the corner | angular part of the outer peripheral part of the holder part 22 between the adjacent segment pieces 24 is missing.

  When the cartridge 33 is removed from the segment piece 24 in the cartridge removing step P5, the connection groove 24c is then formed in the coil connection portion 24b of each segment piece 24 in the connection groove forming step P6.

  FIG. 15 is a cross-sectional view showing a connection groove forming mold, and FIGS. 16A to 16C are explanatory views showing processing steps of the connection groove by the connection groove forming mold.

  As shown in FIG. 15, the connection groove forming die 61 has an upper die 62 and a lower die 63, and the lower die 63 is provided with a support base 64 that is movable in the vertical direction. 64 is supported by a spring 65 and held at a predetermined position. A support pin 66 projecting upward is provided at the shaft center of the support base 64, and the holder portion 22 to which the segment piece 24 is fixed is inserted into the support pin 66 in the shaft hole 23 and supported by the support base 64. It is arranged in a state where it is positioned on.

  As can be seen from FIG. 16A, a plurality of punches 67 (male type) corresponding to the number of segment pieces 24 are arranged in a radial pattern on the lower die 63, and the coil connecting portions 24b of the segment pieces 24 are arranged. The prepared holes 32 are opposed to the corresponding punches 67. On the other hand, the upper die 62 is provided with a plurality of dies 68 (female dies) corresponding to the punches 67, and these dies 68 are provided with a scrap discharge portion 69.

  When the upper die 62 is pushed downward by a pressing device (not shown) and moved downward, each segment piece 24 is pushed downward by the upper die 62 and moves downward together with the support base 64 against the spring force of the spring 65. Moving. When each segment piece 24 moves downward, as shown in FIG. 16B, the portion including the pilot hole 32 of the coil connection portion 24 b is cut into a groove shape by pressing, that is, shearing by each punch 67 and die 68. The As a result, as shown in FIG. 16C, the resin material filled in the lower holes 32 is removed together with the lower holes 32, and groove-shaped connection grooves 24 c are formed in the coil connection portions 24 b of the segment pieces 24. .

  Reference numeral 71 denotes an ejector for removing each segment piece 24 from the punch 67 after processing.

  Here, in the manufacturing method of the commutator 21, the pilot hole 32 is formed in advance in the coil connection portion 24b, so that the shear force necessary for processing the connection groove 24c by the punch 67 and the die 68 is applied to the coil connection portion. Compared to the case where the pilot hole 32 is not previously formed in 24b, it can be made smaller and the processing can be facilitated. Further, since the shearing force necessary for the processing of the connection groove 24c can be reduced as compared with the case where the pilot hole 32 is not formed, the load applied to the holder portion 22 when the connection groove 24c is processed can be reduced. It is possible to prevent the holder portion 22 from being damaged.

  As described above, in the method for manufacturing the commutator 21, the coil connection portion 24b is provided with the pilot hole 32 in advance, and the connection groove 24c is formed by cutting the portion including the pilot hole 32 by pressing. The machining of the groove 24c can be facilitated, and the load applied to the holder portion 22 during the machining can be reduced to prevent the holder portion 22 from being damaged.

  FIG. 17 is a perspective view showing a modification of the segment piece shown in FIG.

  In the segment piece 24 shown in FIG. 5, the pilot hole 32 is formed in advance in the coil connection portion 24b. However, as in the modification shown in FIG. 17, the shape corresponding to the connection groove 24c in advance in the coil connection portion 24b. A lower groove 72 (temporary groove) may be formed. In this case, in the connection groove forming step P6, the portion including the lower groove 72 is cut by press working using the punch 67 and the die 68 to form the connection groove 24c.

  In FIG. 17, the same reference numerals are given to the portions corresponding to the portions described above.

  It goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, in the above-described embodiment, the present invention is applied to the flat commutator 21 used for the starter motor 11. However, the present invention is not limited to this. For example, the electric motor used as a drive source for an electric power steering or a fuel pump. The present invention may be applied to the flat type commutator.

  In the above embodiment, the cartridge 33 is formed of non-reinforced nylon 66. However, the present invention is not limited to this, and other polyamide resins such as nylon 6 (PA6) and nylon 46 (PA46) are used. Alternatively, the cartridge 33 may be formed of other resin materials such as these reinforced polyamide-based resins and resins other than polyamide-based resins.

  Further, the connecting groove 24c is formed by pressing from the direction perpendicular to the slidable contact surface 24a, so that the shape of the armature coil 18 is difficult to be removed or the shape of the armature coil 18 is easily adhered to the outer peripheral surface. The degree of freedom can be increased.

  Further, in the above-described embodiment, the convex portion 37 of the cartridge 33 is provided at the proximal end portion of the partition wall 36, but is not limited thereto, and is provided so as to protrude in the circumferential direction on both side portions of the partition wall 36. If it does, the position does not matter.

It is sectional drawing which shows the internal structure of the starter motor used for a two-wheeled vehicle (motorcycle). FIG. 2 is a partially cutaway perspective view showing details of the commutator shown in FIG. 1. It is process drawing which shows the manufacturing process of the commutator shown in FIG. It is a perspective view which shows a segment piece formation process schematically. It is a perspective view which shows the detail of the segment piece formed by the segment piece formation process shown in FIG. It is a front view which shows the structure of a cartridge. It is sectional drawing which follows the AA line in FIG. (A), (b) is a perspective view which shows the attachment procedure of the segment piece to a cartridge, respectively. It is a front view which shows the cartridge in the state in which the several segment piece was mounted | worn. It is sectional drawing which shows the processing state of the anchor by an anchor formation type | mold. It is a perspective view which shows the detail of the segment piece in which the anchor was formed. It is sectional drawing which shows the processing state of the shaping | molding die in a holder part shaping | molding process. It is sectional drawing which shows the arrangement | positioning state of the cartridge and segment piece inside a shaping | molding die. (A)-(c) is explanatory drawing which shows the procedure in which a holder part is resin-molded with a shaping | molding die, respectively. It is sectional drawing which shows a connection groove | channel formation type | mold. (A)-(c) is explanatory drawing which shows the process sequence of the connection groove | channel by a connection groove | channel formation type | mold, respectively. It is a perspective view which shows the modification of the segment piece shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Starter motor 12a, 12b Cover 13 York 14 Amateur 15 Amateur shaft 16a, 16b Bearing 17 Amateur core 18 Amateur coil 21 Flat type commutator 22 Holder part 23 Shaft hole 24 Segment piece 24a Sliding contact surface 24b Coil connection part 24c Connection groove 24d Main body Portion 24e Fixing convex portion 25 Slit 26a, 26b Brush 27a, 27b Spring 28 Magnet 31 Base material 32 Lower hole 33 Cartridge 34 Substrate portion 35 Outer peripheral wall 36 Partition wall 36a Inclined surface (inclined portion)
37 convex portion 38 protective surface 41 anchor forming die 42 upper die 43 lower die 44 stripper 45 spring 46 punch holder 47 punch 47a nail shaving portion 48 anchor 51 molding die 52 upper die 53 lower die 54 molding chamber 55 cartridge accommodating portion 55a support surface 55b First positioning surface 56 Segment piece support portion 56a Support surface 56b Second positioning surface 57 Gate 58 Tapered surface 61 Connection groove forming die 62 Upper die 63 Lower die 64 Support base 65 Spring 66 Support pin 67 Punch 68 Die 69 Scrap Ejector 71 Ejector 72 Lower groove P1 Segment piece forming process P2 Cartridge mounting process P3 Anchor forming process P4 Holder forming process P5 Cartridge removing process P6 Connection groove forming process

Claims (4)

A flat commutator manufacturing method comprising: a resin holder portion fixed to an amateur shaft; and a plurality of metal segment pieces arranged in the circumferential direction and fixed to the holder portion with a sliding contact surface facing in the axial direction. Because
Attaching a plurality of the segment pieces to the cartridge made of resin having a protective surface covering the sliding contact surface at predetermined intervals in the circumferential direction; and
Placing the cartridge with a plurality of the segment pieces in a mold, and molding the holder portion with a resin material;
Possess a step of removing the cartridge from the segment piece after the holder portion is formed,
The molding die is provided with a first positioning surface on which the outer periphery of the cartridge abuts and a second positioning surface facing the outer periphery of the segment piece with a predetermined interval, and the resin material is formed of the molding die. flat commutator manufacturing method characterized by Rukoto filled in the forming die from the shaft center portion. 2. The method of manufacturing a flat commutator according to claim 1 , wherein the cartridge is detached from the segment piece under a state of a glass transition temperature or higher. 3. The method of manufacturing a flat commutator according to claim 1 , wherein the cartridge is made of a non-reinforced polyamide resin. 4. The method of manufacturing a flat commutator according to claim 3 , wherein the cartridge is made of nylon 66.

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