JP5123084B2 - Commutator manufacturing method - Google Patents

Description

  The present invention relates to a method of manufacturing a commutator used in a rotating electrical machine such as a DC motor or a DC generator.

  Conventionally, as a method of manufacturing a commutator, a plurality of copper commutator pieces are arranged at equal intervals in the circumferential direction so as to be separated from each other, and a resin is injected into the inside thereof to insert-mold, thereby commutator pieces and a resin body And after the resin material is insert-molded and integrated inside the copper commutator piece base material formed in a cylindrical shape, a predetermined interval in the circumferential direction with respect to the commutator piece base material And a method in which each commutator piece is arranged on the outer peripheral surface of the resin body at equal intervals by slitting the substrate into a plurality of commutator pieces (for example, see Patent Document 1). It has been. The latter is easier than the former and is often used to manufacture commutators with relatively small dimensions.

  The commutator formed in this manner is integrally attached to the rotating shaft of the rotor, and rotates with the rotating shaft in a state where the brush is in contact with the outer peripheral surface thereof. It is desired to be disposed on a true cylindrical surface centering on the rotation axis. Therefore, in manufacturing the rotor, after the commutator is attached to the rotating shaft, the finishing process is generally performed a plurality of times so that the outer peripheral surface of the commutator is coaxial with the rotating shaft.

Further, if the commutator piece and the resin body are not firmly connected, the commutator piece may be lifted from the resin body by centrifugal force. Various measures are taken, such as forming a protruding portion in the circumferential direction in the groove portion that has been cut and raised, in addition to a locking claw that is formed by cutting and raising the inner surface so as to be securely held.
JP 2000-102225 A

  However, even if the commutator piece and the resin body are firmly coupled, an error of several tens to several hundreds μm is generated on the outer peripheral surface of the commutator according to the distortion due to the processing accuracy of the commutator piece base material. It is inevitable. When the outer peripheral accuracy of the commutator is low, it has been necessary to perform outer peripheral cutting before attaching to the rotating shaft to increase the outer peripheral accuracy of the commutator.

  This invention is made in view of such a background, and it aims at providing the manufacturing method which improves the outer periphery precision of the commutator by which several commutator piece was arrange | positioned on the outer periphery.

  In order to solve the above problems, the present invention is a method of manufacturing a commutator used in a rotating electrical machine, wherein a substantially cylindrical commutator piece base material is inserted into a mold, and the inside of the commutator piece base material A step of forming a commutator base material in which the commutator piece base material and the substantially cylindrical resin body are integrated, and guiding the through-hole formed in the resin body A step of ironing the outer peripheral surface of the commutator piece base material, and slitting the commutator piece base material subjected to the ironing process, thereby converting the commutator piece base material into a plurality of commutator pieces. And a step of dividing.

  In this case, it is preferable that the slit processing forms a slit based on the through hole.

  According to the present invention, by performing ironing on the outer peripheral surface of the commutator piece base material after insert molding, the outer peripheral surface of the commutator piece base material is disposed on a true cylindrical surface centering on the through hole of the resin body, The outer periphery accuracy of the commutator in which a plurality of commutator pieces are arranged by slit processing can be improved. Thereby, the finishing process of the rotor several times required when the accuracy of the outer peripheral surface of the commutator is low can be omitted or the number of times can be reduced. Further, the commutator piece base material has an increased hardness on the outer peripheral surface due to plastic deformation by ironing, so that the amount of burrs generated during subsequent slit processing and finishing processing is reduced.

  In addition, by forming slits based on the through-holes of the resin body, the slitting process can improve the placement accuracy of the commutator pieces in addition to the accuracy of the outer peripheral surface of the commutator.

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

  FIG. 1 is a cross-sectional view of an electric motor device to which a commutator 10 according to an embodiment is applied. The electric motor device is a drive device for opening and closing a window mounted on a vehicle, and is integrally coupled to a brushed DC motor 1 (hereinafter simply referred to as a motor) and a bottomed cylindrical casing 2 that also serves as a yoke thereof. The reduced speed reduction device 3 is configured.

  The illustrated motor 1 includes a rotor 4 rotatably received in a casing 2, and a plurality of permanent magnets 7 disposed on a corresponding inner peripheral surface of the casing 2 so as to surround the rotor 4. The DC motor has a general structure including a brush 8 that is in sliding contact with the rotor 4. The rotor 4 includes a metal rotary shaft 5 rotatably held in the casing 2, an armature 6 provided coaxially and integrally with the rotary shaft 5, and coaxial and integral with the rotary shaft 5 adjacent to the armature 6. It is comprised from the substantially cylindrical commutator 10 attached to. The brush 8 is provided integrally with the casing 2 via the reduction gear 3, and the tip thereof is in sliding contact with the outer peripheral surface of the commutator 10.

  The rotating shaft 5 extends into the resin speed reducer 3 on the side protruding from the casing 2, and is supported by two bearings 9 a and 9 b provided in the speed reducer 3. Further, the end of the rotary shaft 5 is pivotally supported by a bearing 9 c provided on the casing 2 on the side opposite to the speed reducer 3. A worm 5a is integrally formed at an intermediate portion of the rotating shaft 5 projecting toward the speed reduction device 3, and the speed reduction device 3 is configured by gear coupling of the worm wheel 17 to the worm 5a. The shaft of the worm wheel 17 is an output shaft of a motor device that drives a link mechanism of a regulator for opening and closing a window (not shown).

  FIG. 2 is a perspective view of the commutator 10 according to the embodiment, and FIG. 3 is a plan view of the commutator 10 according to the embodiment. As shown in FIGS. 2 and 3, the commutator 10 is disposed at equal intervals in the circumferential direction on the outer periphery of the cylindrical resin body 11 having a through hole 11 a into which the rotating shaft 5 is inserted, and the resin body 11. It is composed of eight commutator pieces 12. The commutator pieces 12 are all formed in the same shape. Each of the commutator pieces 12 has an arc-shaped slidable contact surface 12a that forms the outer peripheral surface of the commutator 10, and the axis of the commutator 10, that is, the axis A of the through hole 11a. And bundling claws 12b projecting radially outward from one end in the direction. The commutator pieces 12 form slits 13 between the commutator pieces 12 adjacent to each other, and are electrically independent from each other.

  Next, a method for manufacturing the commutator 10 will be described. FIG. 4 is a flowchart illustrating a method for manufacturing the commutator 10, and FIGS. 5 and 6 are explanatory diagrams relating to a method for manufacturing the commutator 10. 5 is a perspective view of the commutator base material 10 ′, and FIG. 6 is a side view showing a state of ironing, in which the die 23 is broken at the center of the recess 24.

  First, the commutator piece base material 15 is inserted into a mold (not shown) and the commutator base material 10 'is resin-molded (step 1). Specifically, a copper commutator piece base material 15 that has a cylindrical shape and includes a binding claw 12b that protrudes radially outward at one end in the axial direction is set in a mold. Then, the temperature of the mold is set to be equal to or higher than the curing temperature of the thermosetting resin that is a raw material of the resin body 11, and the resin that is heated to the glass transition point or more and has increased fluidity Inject inside. After elapse of a predetermined curing time, the cured resin is taken out from the mold to form a commutator base material 10 ′ in which the commutator piece base material 15 and the resin body 11 are integrated as shown in FIG. 5. The inner peripheral surface of the commutator piece base material 15 is formed with various locking claws, locking grooves, and the like (not shown), so that the commutator piece base material 15 and the resin body 11 are firmly connected. Is realized.

  Next, ironing is performed on the commutator base material 10 ′ formed in Step 1 using the ironing device 21 (Step 2). Specifically, as shown in FIG. 6, the commutator base material 10 ′ is set on a punch 22 that is complementary to the top surface shape of the commutator base material 10 ′. The die 23 disposed below the punch 22 is formed with a cylindrical recess 24 having an inner diameter slightly smaller than the outer diameter of the commutator base material 10 ', and an opening edge (see FIG. A conical inclined surface 24b whose diameter is increased toward the end edge is formed on the upper edge of the inside. In addition, a guide post 25 inserted into the through hole 11a of the commutator base material 10 ′ protrudes coaxially with the recess 24 toward the opening of the recess 24 (upward in the figure) at the center of the bottom surface of the recess 24. It is installed. By pressing downward the punch 22 on which the commutator base material 10 ′ is set, the commutator base material 10 ′ moves downward along the guide post 25, and the commutator piece base material 15 extends along the inclined surface 24b. To cause plastic deformation and reduce its wall thickness. Thereby, the commutator base material 10 'is formed in a cylindrical shape coaxial with the through hole 11a with high accuracy. The punch 22 is not limited to the complementary shape as described above, and may be a normal flat shape.

  Next, slit processing is performed on the commutator base material 10 ′ taken out from the ironing device 21 using a slit processing device (not shown) (step 3). Specifically, slits 13 along the axis A are formed at equal intervals on the outer peripheral surface of the commutator base material 10 ′ in which the through holes 11 a are held. In the present embodiment, eight slits 13 are formed at intervals of 45 ° from the radially outer side toward the axis A with respect to the cylindrical commutator base material 10 ′. By forming the slit 13 deeper than the thickness of the thinned commutator piece base material 15, the commutator piece base material 15 becomes eight commutator pieces 12 that are electrically separated, as shown in FIGS. A commutator 10 is formed.

  After the slit processing, the rotary shaft 5 is press-fitted into the through-hole 11a of the commutator 10 to integrate them (step 4), and the commutator 10 is connected to the rotor 4 attached to the rotary shaft 5 with respect to the commutator piece. By performing the cutting process so that the 12 sliding contact surfaces 12a are arranged on the cylindrical surface centering on the rotation axis 5, that is, the cylindrical surface centering on the axis A of the through-hole 11a (step 5), the commutator 10 is completed.

  Thus, the commutator 10 is formed on the cylindrical surface centered on the through hole 11a when the commutator piece base material 15 is ironed at the stage of the commutator base material 10 ′. It will be arranged with high accuracy. For example, a method of ironing the commutator piece base material 15 before insert molding and then integrating with the resin is also conceivable, but in this case, the outer peripheral accuracy of the commutator piece base material 15 is reduced during insert molding. There is a risk of doing. On the other hand, in the case of this embodiment, since ironing is performed after insert molding, there is no such a possibility.

  When the through hole 11a is guided to the guide post 25 during the ironing process, in other words, the through hole 11a serves as a reference for the ironing process, for example, the through hole 11a is separated from the axis of the resin body 11. Even if the commutator piece 12 is displaced, the sliding contact surface 12a of the commutator piece 12 is disposed on the cylindrical surface with the through hole 11a as the center. It is arranged with high accuracy on a central cylindrical surface. As a result, the number of times of cutting that is the finishing process of the rotor 4 can be reduced to one.

  On the other hand, when the through hole 11a is guided to the guide post 25 during the ironing process, the inner peripheral accuracy of the through hole 11a is improved. Further, since the commutator piece 12 is arranged with reference to the through hole 11a (guide post 25), even if the inner peripheral accuracy of the through hole 11a is not so high, the commutator is attached to the rotating shaft 5 even if it is not so high. The placement accuracy of the piece 12 is ensured. In addition, the inner diameter of the through hole 11a before the ironing process is equal to or slightly smaller than the outer diameter of the guide post 25.

  Further, the commutator piece 12 is plastically deformed by ironing to increase its hardness, and the occurrence of burrs during slit processing and finishing is suppressed, so that the outer peripheral accuracy of the commutator 10 is only further improved. In addition, the durability of the commutator 10 is also improved.

  In addition, the slit 13 is formed on the outer peripheral surface of the commutator base material 10 ′ while the through hole 11 a is held during the slit processing. In other words, the through hole 11 a becomes a reference for the slit processing. Thereby, not only the outer periphery accuracy of the commutator 10 but also the arrangement accuracy of each commutator piece 12 can be improved.

  This is the end of the description of specific embodiments, but the present invention is not limited to these embodiments. For example, in the above embodiment, the commutator is applied to an electric motor device for opening and closing a window, but the application target is not limited to this, and any DC motor with a brush can be used for any purpose. It may be. The application target of the commutator is not limited to a motor that converts electrical energy into rotational kinetic energy, but may be a DC generator that converts rotational kinetic energy into electrical energy.

  In the above embodiment, the commutator piece base material is made of copper, but the raw material is not limited to this, and any material may be used as long as it has electrical conductivity and plasticity. On the other hand, the raw material of the resin body is not limited to the thermosetting resin, and may be a plastic resin. Further, in addition to the above changes, the shape and quantity of the commutator pieces can be appropriately changed as long as they do not depart from the spirit of the present invention.

Sectional drawing of the electric motor apparatus which applied the commutator which concerns on embodiment Plan view of commutator according to the embodiment Side view of commutator according to embodiment The flowchart which shows the manufacturing method of the commutator which concerns on embodiment Explanatory drawing of the manufacturing method of the commutator concerning an embodiment Explanatory drawing of the manufacturing method of the commutator concerning an embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Motor 4 Rotor 5 Rotating shaft 8 Brush 10 Commutator 10 'Commutator base material 11 Resin body 11a Through hole 12 Commutator piece 12a Sliding contact surface 13 Slit 15 Commutator piece base material A Axis

Claims (2)

A method of manufacturing a commutator used in a rotating electrical machine,
The commutator piece base material and the substantially cylindrical resin body are integrated by inserting a substantially cylindrical commutator piece base material into a mold and injecting resin into the commutator piece base material. Forming a commutator base material;
A step of ironing the outer peripheral surface of the commutator piece base material while guiding through holes formed in the resin body; and
A step of dividing the commutator piece base material into a plurality of commutator pieces by slitting the commutator piece base material subjected to the ironing process. Production method.   The method of manufacturing a commutator according to claim 1, wherein the slit processing forms a slit based on the through hole.

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