JP5953143B2 - DC motor manufacturing method - Google Patents

Description

The present invention relates to a method of manufacturing a direct current motor, a method of manufacturing a suitable brush for direct current motor using the particular brake system for a vehicle.

  Examples of conventional DC motors are described in Patent Document 1 and Patent Document 2. In the DC motor with a brush described in these publications, a resin plate is employed in a portion where the electric motor is connected to the brake portion. Specifically, in the electric brake device for a vehicle described in Patent Document 1, a motor chamber is formed inside a motor case of an electric motor, and the motor case is attached to a housing portion of a caliper body that constitutes a brake portion. . Then, a metal yoke integrally formed with a flange portion projecting outward in the radial direction and having a cylindrical shape with a bottom, and an outer peripheral portion of the yoke flange portion are in contact with the flange portion of the yoke. A motor case is constituted by a brush holder made of resin, for example, synthetic resin, and a metal lid member sandwiching the brush holder between the yoke and the yoke.

  Further, in the electric brake device for a vehicle described in Patent Document 2, similarly to Patent Document 1, the motor case is attached to the housing portion of the caliper body, and the flange portion that projects the motor case radially outward is opened. A metal yoke integrally formed on the end side and formed in a bottomed cylindrical shape, a metal bearing holder disposed at the opening end of the yoke, and an outer peripheral portion in contact with the flange portion of the yoke A lid member made of a resin, for example, a synthetic resin, is used to close the open end of the yoke. That is, in Patent Document 1, the resin disk-shaped member is disposed on the motor side with respect to the bearing holder, whereas in Patent Document 2, it is disposed on the brake side with respect to the bearing holder.

JP 2011-179658 A JP 2011-179655 A

  In the electric brake device for a vehicle described in Patent Document 1 and Patent Document 2, a resin-made disk-shaped member is disposed in the vicinity of the axial direction of the support bearing that supports the electric motor in order to reduce the weight. doing. And the outer peripheral part of a support bearing is hold | maintained with the cover member (patent document 1) or the bearing holder (patent document 2) obtained by sheet-metal processing. Since a sheet metal bearing support material that is less likely to change in temperature and easily obtains processing accuracy than a resin material is disposed, it is expected that situations such as rattling can be avoided even during vehicle operation.

  However, the electric motors described in these publications use a sheet metal lid member or a bearing holder as a bearing support member and substantially cover the opening end of the yoke, so that the motor weight increases and man-hours due to sheet metal processing increase. Tied to Various elements used for vehicles are desired to be as light as possible, and providing a bearing support member in addition to a material covering the opening of the yoke causes not only an increase in weight but also an increase in cost.

  The present invention has been made in view of the above-described problems of the prior art, and is to reduce vibration and noise caused by a bearing support portion in a DC motor with a brush having a resin bearing support member. Another object is to maintain and improve manufacturability and workability.

A feature of the present invention that achieves the above object is that a case formed in a cup shape, a brush plate covering an opening of the case, a rotor housed in the case and having an armature and a commutator, and the rectifier A brush press-contacted to the child, a rear bearing at one end, a front bearing attached to an intermediate portion thereof, and a rotary shaft fixedly mounted between the rear bearing and the front bearing. In a method of manufacturing a DC motor with a brush which is assembled by contacting a driven body driven by the DC motor with a brush plate, the brush plate is made of resin, and the brush side is the outer peripheral side of the resin brush plate. A plurality of arc-shaped ribs extending in the circumferential direction are formed on the surface of the resin integrally with the brush plate, and the front bearing is press-fitted into the inner peripheral side of the brush plate. By the driven body in a state that the assembled contact with the brush plate has to restrict deformation of the brush plate in the inner circumferential surface of the case so as repulsive force to the case to the ribs occurs, the The front bearing is clamped in the axial direction by the pressing force of the brush plate based on the repulsive force and the pressing force of the driven body during assembly.

In this feature, it is desirable that the outer ring of the front bearing is clamped in the axial direction by the pressing force of the driven body and the brush plate, and the plurality of ribs formed on the resin brush plate include the brush It is desirable that a plurality of radial ribs extending from the front bearing holding portion to the outer peripheral side are formed on the surface of the brush plate where the ribs extending in the circumferential direction are formed. It may be formed.

  According to the present invention, when the support bearing for rotating and supporting the electric motor is supported by the resin plate, since the rib is provided on the outer peripheral portion of the plate, the deformation at the bearing holding portion is suppressed, and this is caused by the bearing holding portion. Vibration and noise can be reduced. Further, only the ribs are formed, and the manufacturability and workability can be maintained and improved.

It is the longitudinal cross-sectional view and front view of one Example of the DC motor which concerns on this invention. It is the front-back perspective view and front view of a brush plate with which the DC motor shown in FIG. It is a principal part enlarged view of the DC motor shown in FIG.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1A is a longitudinal sectional view of an embodiment of a DC motor according to the present invention, and FIG. 1B is a side view thereof. 2 is a view of the brush plate 17 included in the DC motor 100 shown in FIG. 1, FIG. 2 (a) is a perspective view from the oblique front, FIG. 2 (b) is a perspective view from the oblique rear, and FIG. 2 (c) is a front view from the rear. The DC motor shown in FIG. 1 is used for an anti-lock brake system (ABS) provided in a vehicle, but the present invention is not limited to that used for ABS.

  The DC motor 100 according to this embodiment is a brushed DC motor. An annular permanent magnet 16 constituting a field of the electric motor 100 is fixed to a peripheral wall portion 12 of a case (yoke) 11 in which an iron plate is formed in a cup shape by pressing or the like. The case 11 and the permanent magnet 16 constitute a stator of the electric motor 100. An armature 43 is disposed so as to face the permanent magnet 16. The armature 43 includes a laminated steel plate (core) 41 formed by laminating die-cut silicon steel plates and the like, and a winding 42 wound around a convex pole formed on the laminated steel plate 41. . In addition, the outer surface side of the laminated steel plate 41 is molded with a mold resin to ensure insulation.

  The laminated steel plate 41 around which the winding 42 is wound is attached to the rotating shaft 32. As the rotary shaft 32 rotates, the pump 95 attached to one end of the electric motor 100 is driven to rotate. One end portion of the rotating shaft 32 is supported by a rear side rolling bearing 34 held by a rear bearing holding portion 13 formed by pressing or the like at the center portion of the bottom portion (left end portion in FIG. 1A) of the case 11. Here, the rear bearing holding portion 13 is formed in a convex shape inside the case 11. A cam portion 35 is formed at the other end of the rotating shaft 32.

  In order to supply power to the winding 42, the commutator 22 is attached to the rotating shaft 32, and the two brushes 21 are pressed against the commutator 22 by a coil spring 74 (see FIG. 2C). ing. The brush 21 is electrically connected to terminals 25 a and 25 b attached to the brush plate 17. The terminals 25 a and 25 b are protected from insulation by the cylindrical portion 83 of the brush plate 17.

  The opening of the case 11 is covered with a brush plate 17. Flange 18 for axial and circumferential positioning is formed at four locations in the circumferential direction of the outer periphery of brush plate 17. The brush plate 17 is fitted in the case 11 in an airtight manner. An opening for holding the front side rolling bearing 33 is formed at the center of the brush plate 17, and the front side rolling bearing 33 fixed to the rotating shaft 32 is held via the collar 5. A flange 14 is formed on the outer periphery of the case 11, and a pump 95 is attached by inserting a bolt into a pump attachment hole 15 formed in the flange 14.

  Here, the brush plate 17 is made of resin and is integrally formed with the terminals 25a and 25b. Each of the terminals 25a and 25b has a rectangular shape on one end side, and the rectangular portion forms convex protrusions 26a and 26b. A pigtail 75 having an end fixed to the brush 21 and guided by a pigtail guide 73 is attached to the protrusions 26a and 26b of the terminals 25a and 25b. The other end side of the terminals 25a and 25b forms a connector portion.

  The terminals 25a and 25b can be spot-welded or fused, and after a steel plate or copper plate, which is a conductive material, is punched out by a press or the like, a convex shape is formed at the tip by a press or the like, and a 90-degree bent shape is formed at an intermediate portion ing. An intermediate portion of the terminals 25a and 25b is formed as a wiring portion, and has a shape that fits in a ring portion of the brush plate 17 formed in a ring shape. The two connector portions of the terminals 25a and 25b are substantially parallel and formed in a cylindrical shape, and are used for connection to the power supply portion of the pump 95. The axial length of the connector portion is determined according to the pump 95 to be driven.

  The brush 21 is held by box-shaped brush holders 72 provided at two locations on the back side of the brush plate 17. The brush holder 72 is movable in the radial direction with a brush holder slit formed in the radial direction as a guide. A coil spring 74 whose end is fixed to a spring holder slit 76 formed in the spring holder 71 prevents the brush 21 from popping out.

  If the two terminals 25a and 25b are integrated in advance with an integrated member made of an insulating resin, and the resin is integrally formed with the integrated terminal, positioning is performed while ensuring airtightness. Is possible. As the material of the integrated member, an adhesive material having good airtightness and adhesiveness is used. The mutual positional relationship between the plurality of (two in this embodiment) terminals 25a and 25b can be positioned in advance, which facilitates positioning work during resin integral molding and improves workability.

  In the DC motor 100 of this embodiment configured as described above, since the brush plate 17 is integrated with resin, insulation, weight reduction, and airtightness can be improved. However, since the brush plate 17 is integrated, supporting the load applied to the outer ring of the front side rolling bearing 33 becomes a problem.

  Since the DC motor 100 of the present invention is used for ABS pump driving or the like, a variable load of the pump acts on the front side rolling bearing 33. This fluctuating load may cause creep distortion in the outer ring of the front side rolling bearing 33. Alternatively, if the outer ring of the rolling bearing 33 is held by the resin brush plate 17, a gap (backlash) may occur between the outer ring of the rolling bearing 33 and the inner periphery of the brush plate 17 due to long-term use. If backlash occurs, it may cause noise and vibration.

  Therefore, in this embodiment, in order to make the DC motor light and have little backlash, the front side bearing 33 holding portion of the brush plate 17 is made of resin with an outer peripheral rib 61 and is, for example, an interference fit such as press fitting. The bearing 33 is held on the inner peripheral side of the brush plate 17. The pump 95 is assembled with the front bearing 33 held on the inner peripheral portion of the resin brush plate 17. Thereby, the pressing force from both axial sides acts on the rolling bearing 33 over a long period of time.

  This will be described with reference to FIG. 1 (a) and FIG. 3 and FIG. 3A is a longitudinal sectional view showing the assembly relationship between the front bearing 33, the brush plate 17, and the yoke 11, and FIG. 3B schematically shows the force acting on the resin brush plate 17 in a beam structure. FIG.

  As shown in FIGS. 2B and 2C, the brush holder 72 is disposed on the brush plate 17 at an interval of approximately 90 degrees in the circumferential direction. Except for the circumferential position where the brush holder 72 is formed and the symmetrical position with the brush holder 72 (predetermined range centered at a position 180 degrees apart), the outer periphery of the brush plate 17 is axially Arc-shaped ribs 61 having a predetermined length are formed. The flange 18 is formed at a position symmetrical to the brush holder 72 and the brush holder 72. The portion where the flange 18 is formed serves as a circumferential boundary of the rib 61. Since the boundary is formed in the rib 61, the replacement of the brush 21 is facilitated. The radial thickness and the circumferential length of the rib 61 are set in consideration of the following deformation.

  That is, since the brush plate 17 is made of resin, the elastic deformation is easier than that made of metal, and internal stress is generated in the brush plate 17 due to the elastic deformation. In this embodiment, this internal stress is used to hold the front bearing 33.

  3A, the broken line 51 indicates that the brush plate 17 is obstructed by the inner peripheral surface 12a of the peripheral wall 12 when the brush plate 17 is brought into contact with the spigot 12b formed on the peripheral wall 12 of the yoke 11. This is a virtual deformation line of the brush plate 17 when it is assumed that the brush plate can be deformed. The DC motor 100 is assembled in a state where the outer ring 33a of the rolling bearing 33 including the outer ring 33a, the inner ring 33b, and the steel ball 33c is press-fitted into the brush plate 17. In this state, the brush portion rate 17 is only subjected to the tightening stress when the rolling bearing 33 is press-fitted on the inner peripheral surface, and the outer peripheral portion and the like are stress-free.

  Next, the assembled DC motor 100 is assembled to the pump 95 using bolts inserted through the pump mounting holes 15. At that time, the corner 95a of the housing of the pump 95 pushes the outer ring 33a of the rolling bearing 33 in the axial direction. Let this pushing force be F. The rolling bearing 33 is pressed into the brush plate 17 and is in close contact with a flange portion 17 a formed on the inner peripheral side of the brush plate 17. Therefore, if the rolling bearing 33 moves in the axial direction, the brush plate also moves in the axial direction together. On the other hand, the axial position of the outer peripheral side of the brush plate 17 is restricted by the spigot portion 12 b of the yoke 11. Thereby, a bending force (bending moment) of size T acts on the inner peripheral side of the brush plate 17.

  If the outer peripheral side of the brush plate 17 is restricted only in the axial direction and can be freely deformed in the radial direction, almost no stress is generated inside the brush plate 17 by assembly. However, in practice, the deformation of the brush plate 17 extending in the radial direction is restricted by the inner peripheral surface 12 a of the yoke 11. As a result, the deformed state indicated by the solid line 52 in FIG. In the state shown by the solid line 52, the rib 61 of the brush plate 17 is restricted from being freely deformed, so that a repulsive force is generated to cause free deformation, which becomes internal stress. This repulsive force varies depending on the axial length L of the rib 61, the radial thickness Δr of the rib 61, the thickness of the cover portion (disk portion) 62 of the brush plate 17, and the like. Generally, the repulsive force increases as the axial length L of the rib 61 and the radial thickness Δr of the rib 61 increase as they increase. As shown in FIG. 3 (b), the pressing force of magnitude Rx is applied from the yoke to the rib 61 by the axial force F during assembly, whereby the rib 61 generates a repulsive force of magnitude Ax.

  The repulsive force Ax generated in the rib 61 acts as a bending moment near the inner peripheral surface of the brush plate 17, and acts as an axial load Sx at the press-fitted portion of the rolling bearing 33. That is, in the rolling bearing 33, F force is applied from the pump side by assembly, and Sx force acts from the brush plate 17 side as a result of the repulsive force of the assembly. These forces are in opposite directions and act as a compressive load on the rolling bearing 33. As a result, even if vibration is generated as a result of the operation of the DC motor 100 or creep distortion occurs in the brush plate 17 due to long-term operation, the force sandwiched from both sides of the rolling bearing 33 can continue to act. Therefore, the vibration caused by the rolling bearing 33 can be suppressed.

  In this embodiment, the ribs in the circumferential direction are formed on the brush plate instead of the radial ribs. The reason is that when a resin brush plate is used, the expected repulsive force is made of steel. This is because the same dimensions are small. Therefore, to obtain the desired repulsive force, it is necessary to enlarge the ribs. In the case of radial ribs, this can be dealt with by increasing the axial dimension, but interference with windings and brushes must be avoided. The axial dimension of the DC motor becomes too large. On the other hand, in the case of the circumferential rib, a sufficient space can be secured even if the brush and the winding are avoided. Of course, it is also possible to use the radial rib and the circumferential rib in combination, create the radial rib within an allowable range, and reduce the size of the circumferential rib.

  As described above, according to the present embodiment, it is possible to reduce the weight by using a resin brush plate, and the rib extending in the circumferential direction is formed on the outer peripheral portion of the brush plate. Thus, it is possible to generate an axial pressing force on the front rolling bearing. The rolling bearing is sandwiched between this pressing force and the pressing force from the pump side at the time of assembly, so even if there is vibration when the DC motor is operated or creep distortion due to long-term use, the rolling bearing The resulting vibration and noise can be suppressed.

  Further, since the brush plate can be integrally molded with resin, the brush plate can be easily manufactured with high accuracy. Furthermore, since the rib formed on the brush plate does not increase the number of parts, the assemblability is not deteriorated and the cost is not increased. Therefore, vibration and noise caused by the front bearing of the DC motor for the pump can be suppressed with a simple configuration.

DESCRIPTION OF SYMBOLS 11 ... Case (yoke), 12 ... Peripheral wall part, 13 ... Rear bearing holding part, 14 ... Flange, 15 ... Pump attachment hole, 16 ... Permanent magnet, 17 ... Brush plate, 18 ... Flange, 21 ... Brush, 22 ... Rectification Child, 24 ... Integral terminal, 25a, 25b ... Terminal, 26a, 26b ... (terminal) projection, 32 ... Rotating shaft, 33 ... Front side rolling bearing, 33a ... Outer ring, 33b ... Inner ring, 33c ... Steel ball, 34 ... Rear-side rolling bearing, 35 ... Cam part, 41 ... Laminated steel sheet, 42 ... Winding, 43 ... Armature, 51 ... Virtual deformation state, 52 ... Deformation state, 61 ... Rib, 62 ... Disk part, 71 ... Spring holder, 72 ... Brush holder, 73 ... Pigtail guide, 74 ... Coil spring, 75 ... Pigtail, 76 ... Spring holder slit, 77 ... Brush holder slit, 83 ... Connector, 95 ... Pon , 100 ... DC motor.

Claims (4)

A case formed in a cup shape, a brush plate covering the opening of the case, a rotor having an armature and a commutator housed in the case, a brush pressed against the commutator, and one end A front bearing is attached to the middle portion of the rear bearing, and the armature is fixed between the rear bearing and the front bearing. The rotating shaft is attached to the brush plate, and the DC motor is driven by the brush motor. In the method of manufacturing a DC motor with a brush that is assembled by contacting the body,
The brush plate is made of resin, and a plurality of arc-shaped ribs extending in the circumferential direction are formed integrally with the brush plate on the outer surface of the resin brush plate and on the brush side, and the brush plate In the state where the front bearing is press-fitted to the inner peripheral side of the casing, the driven body is assembled in contact with the brush plate so that a repulsive force to the case is generated on the rib on the inner peripheral surface of the case. A direct current electric motor characterized in that deformation of the brush plate is restricted, and the front bearing is clamped in the axial direction by the pressing force of the brush plate based on the repulsive force and the pressing force of the driven body during assembly . Manufacturing method . 2. The method of manufacturing a DC motor according to claim 1, wherein an outer ring of the front bearing is held in an axial direction by a pressing force between the driven body and the brush plate. 3. The method of manufacturing a DC motor according to claim 1, wherein the rib formed on the resin brush plate is not formed at a circumferential position where the brush is held. 4. A plurality of radial ribs extending outward from the front bearing holding portion are formed on a surface of the brush plate on which ribs extending in the circumferential direction are formed. A method for producing a DC motor as described in 1.

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