JP2009284679A - Brushless motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a lead wire from being stuck and failure in attaching of a grommet by improving the assembling workability to a bracket by stably fixing a grommet and a bracket holder. <P>SOLUTION: A rubber grommet 41 is attached to a grommet attaching portion 44 cut and formed on an outer circumferential wall 25a of the bracket holder 25 to which a resolver stator 23 is attached. sidewalls 45 are provided so as to be upright on both sides in the circumferential direction of the grommet attaching portion 44. The grommet 41 has an engaging groove portion 43 engaging with the sidewalls 45. The sidewalls 45 are engaged with the engaging groove portion 43, thereby attaching the grommet 41 to the grommet attaching portion 44 in the state where a movement in the dimension direction is regulated. The slippage of the grommet 41 is stopped in the diameter direction for the bracket holder 25, and thus the workability in assembling the bracket holder 25 into the bracket 8 is improved. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a lead wire mounting structure for a brushless motor, and more particularly to a fixing structure for a seal grommet used when mounting a lead wire of a rotation detection device of a brushless motor to a brushless motor body.

  In recent years, electric power steering devices (hereinafter abbreviated as EPS) using an electric motor as a drive source have increased as power steering devices used for assisting steering force of automobiles and the like from the viewpoint of reducing engine load and weight. ing. For such EPS motors, brush DC motors have been used in the past, but nowadays, brushless motors, which are excellent in terms of miniaturization and high performance, are being combined with improvements in control technology. Adoption is increasing.

  On the other hand, in the brushless motor, in order to rotationally drive the rotor, it is necessary to detect the rotational position of the rotor and sequentially excite the stator side coil (stator coil) based on the detected rotor rotational position. Conventionally, detection devices using encoders, Hall ICs, and the like have been used for detecting the rotational position of the rotor. However, in recent years, high-resolution sensors have been required due to demands for higher performance and lower noise in brushless motors. In addition, the use of resolvers with high detection accuracy, simple structure and less failure, and strong resistance to high temperatures and vibration environments is increasing.

This resolver generally includes a resolver rotor that rotates together with a rotor of a motor, and a resolver stator that is disposed outside the resolver rotor. The resolver stator includes an excitation coil and a detection coil, and these coils are connected to a controller or the like provided outside the apparatus via lead wires. For example, in an EPS brushless motor such as Patent Document 1, the resolver stator is attached to a bracket holder made of synthetic resin for insulation and prevention of foreign matter intrusion, and is mounted in a bracket made of aluminum die casting. At this time, the resolver lead wire is attached to the bracket holder using a rubber grommet in order to ensure sealing performance, and the bracket holder is assembled to the bracket together with the grommet into which the lead wire is inserted.
Japanese Patent Application No. 2006-258111

  However, in such a conventional brushless motor, since the grommet is not fixed to the bracket holder in the radial direction and the axial direction, these must be assembled to the bracket in a state where the grommet is not fixed to the dangle. There was a problem that workability was not good. For this reason, when assembling the bracket holder to the bracket, there are problems such that the lead wire is caught between the bracket holder and the bracket, or the grommet is not securely attached to the bracket holder or the bracket.

  Also, from the standpoint of reducing the number of parts, etc., there is also an integrated O-ring for sealing arranged on the outer periphery of the bracket holder with the grommet. In that case, if the grommet becomes unstable, There is a risk of damaging the O-ring. Furthermore, since the grommet is transported and delivered with the bracket holder assembled in advance, the assembled state of both is not stable due to vibration during transportation, etc., and it is necessary to rework before mounting to the bracket. there were.

  The object of the present invention is to improve the assembly workability to the bracket by stably fixing the grommet and the bracket holder, and to prevent the bite of the lead wire, the mounting failure of the grommet, the damage of the O-ring, etc. It is in.

  The brushless motor according to the present invention includes a holder member to which a rotation detection device for detecting the rotation position of the rotor is attached, and a grommet attachment portion formed on the holder member, and a lead wire connected to the rotation detection device. A brushless motor having a grommet to be inserted, wherein the grommet is fitted to a grommet holding portion provided in the grommet mounting portion, and the grommet is controlled in a state where movement in a radial direction is restricted. It has the fitting part with which a grommet attaching part is mounted | worn, It is characterized by the above-mentioned.

  In the present invention, when the grommet is attached to the holder member, the fitting portion and the grommet holding portion are fitted, and the grommet is prevented from coming off in the radial direction with respect to the bracket holder. For this reason, the grommet does not become unstable, the workability when assembling the holder member to other parts is greatly improved, the lead wire can be prevented from being bitten, and the grommet mounting failure can be reduced.

  In the brushless motor, the grommet holding portion is provided with a side wall portion of the grommet mounting portion that is notched in the outer peripheral wall of the holder member, and the fitting portion is formed at a circumferential end portion of the grommet. You may provide the fitting groove part which can be fitted with a side wall part. Further, as the grommet holding part, a fitting piece projecting from the grommet mounting part formed in the outer peripheral wall of the holder member is provided and the fitting piece is formed on the grommet as the fitting part. A fitting hole that can be fitted with may be provided.

  In the brushless motor of the present invention, a holder member to which a rotation detection device for detecting the rotation position of the rotor is attached, and a lead wire attached to a grommet attachment portion formed on the holder member and connected to the rotation detection device are inserted. In a brushless motor having a grommet, a fitting portion that is fitted to the grommet holding portion provided in the grommet attaching portion and is attached to the grommet attaching portion in a state where the movement of the grommet is restricted in the radial direction is provided. Since the grommet is provided, when the grommet is attached to the holder member, the grommet is prevented from being displaced in the radial direction with respect to the holder member, and workability when the holder member is attached to another component can be improved.

  Therefore, the number of assembling steps when attaching the holder member to other parts can be reduced, and the manufacturing cost can be reduced. In addition, the lead wire can be prevented from biting at the time of assembling work and the mounting failure of the grommet can be reduced, so that the product reliability can be improved. Further, in the case where the grommet and the O-ring are integrated, damage to the O-ring during the assembling work can be suppressed, and in this case, the product reliability can be improved. In addition, since the grommets are stably attached to the holder member, the misalignment between them when transported and delivered in a pre-assembled state is reduced, and there is no need for reworking before assembling. Man-hours can be reduced.

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

  FIG. 1 is a cross-sectional view showing a configuration of a brushless motor that is Embodiment 1 of the present invention. As shown in FIG. 1, a brushless motor 1 (hereinafter abbreviated as “motor 1”) is an inner rotor type brushless motor having a stator (stator) 2 on the outside and a rotor (rotor) 3 on the inside. Yes. The motor 1 is used, for example, as a power source of a column assist type electric power steering device (EPS), and applies an operation assisting force to a steering shaft of an automobile. The motor 1 is attached to a speed reduction mechanism provided on the steering shaft, and the rotation of the motor 1 is transmitted to the steering shaft by being decelerated by the speed reduction mechanism.

  The stator 2 includes a bottomed cylindrical case 4, a stator core 5, a stator coil 6 (hereinafter abbreviated as a coil 6) wound around the stator core 5, and a bus bar unit 7 attached to the stator core 5. . The case 4 is formed in a bottomed cylindrical shape with iron or the like, and an aluminum die cast bracket 8 is attached to an opening of the case 4 with a fixing screw (not shown). The stator core 5 has a configuration in which a plurality of (for example, nine) divided cores are assembled in the circumferential direction, and a plurality of teeth protrudes radially inward. The split core is formed by stacking core pieces made of electromagnetic steel plates, and an insulator 11 made of synthetic resin is attached around the core.

  A coil 6 is wound around the outside of the insulator 11, and an end portion 6 a of the coil 6 is drawn out in the radial direction on one end side of the stator core 5. A bus bar unit 7 in which a copper bus bar is insert-molded in a synthetic resin main body is attached to one end side of the stator core 5. Around the bus bar unit 7, a plurality of power feeding terminals 12 project in the radial direction, and when the bus bar unit 7 is attached, the coil end 6 a is welded to the power feeding terminal 12. In the bus bar unit 7, the number of bus bars corresponding to the number of phases of the motor 1 (here, three for U phase, V phase, W phase) is provided, and each coil 6 is a power supply terminal corresponding to that phase. 12 is electrically connected. The stator core 5 is press-fitted and fixed in the case 4 after the bus bar unit 7 is attached.

  A rotor 3 is inserted inside the stator 2. The rotor 3 has a rotor shaft 13, and the rotor shaft 13 is rotatably supported by bearings 14a and 14b. The bearing 14 a is fixed to the center of the bottom of the case 4, and the bearing 14 b is fixed to the center of the bracket 8. A cylindrical rotor core 15 is fixed to the rotor shaft 13, and a segment type magnet (permanent magnet) 16 is attached to the outer periphery thereof. A synthetic resin magnet holder 17 is inserted on the rotor shaft 13, and the magnet 16 is disposed on the outer periphery of the rotor core 15 so as to be held by the magnet holder 17. In the motor 1, six magnets 16 are arranged along the circumferential direction, and a cylindrical magnet cover 18 is attached to the outside of the magnet 16.

  A rotor (resolver rotor) 22 of a resolver 21 serving as a rotation angle detection unit is attached to the end of the magnet holder 17. On the other hand, the stator (resolver stator) 23 of the resolver 21 is press-fitted into a metal resolver holder 24 and is fixed to a bracket holder (holder member) 25 in that state. The bracket holder 25 is made of synthetic resin, and a metal female screw portion 27 is insert-molded. A mounting screw 28 is screwed into the female screw portion 27 from the outside of the bracket 8, whereby the resolver holder 24 is fixed to the inside of the bracket 8.

  A power supply wiring 29 to which external power supply terminals 31 (U, V, W) are connected is assembled to the bracket 8. On the other hand, the bus bar unit 7 is provided with bus bar terminals 32 (U, V, W) and protrudes in the axial direction. When the motor 1 is assembled, the bus bar terminal 32 faces the external power feeding terminal 31 in parallel. In the motor 1, after the bracket 8 is attached to the case 4, the bus bar terminal 32 and the external power feeding terminal 31 are fixed by welding. A work hole 33 is formed in the bracket 8, and a bracket cap 34 is attached to the work hole 33 after the welding process.

  On the other hand, the resolver holder 24 is formed in a bottomed cylindrical shape, and is inserted and attached to the central portion of the bracket holder 25. On the other hand, the opening side end portion where the flange portion 24 a is formed is lightly press-fitted into the outer periphery of the end portion of the rib 26 provided in the bracket 8. The rib 26 projects in a cylindrical shape toward the axial direction at the center of the bracket 8, and a bearing 14 b that supports the rotor shaft 13 is fixed to the inside of the rib 26. Therefore, the resolver stator 23 is mounted concentrically with the rotor shaft 13 by lightly press-fitting the resolver holder 24 into the rib 26.

  A lead wire 9 for transmitting a signal output as the rotor 22 rotates is fixed to the resolver stator 23. The lead wire 9 is routed along the circumferential direction between the bracket 8 and the bracket holder 25, and from the outer peripheral portion of the bracket 8 through a lead wire insertion hole 10 of a rubber grommet 41 (hereinafter abbreviated as grommet 41). It is pulled out of the device. 2 is a plan view showing the bracket holder 25 with the lead wire 9 attached, FIG. 3 is a perspective view showing the configuration of the bracket holder 25 and the grommet 41, and FIG. 4 is a side view of the grommet 41. As shown in FIG. 2, the bracket holder 25 is attached to the bracket 8 in a state where the grommet 41 is assembled. An O-ring 42 is integrally formed with the grommet 41, and when the bracket holder 25 is attached to the bracket 8, the O-ring 42 is attached to the bracket 8.

  Here, in the conventional brushless motor, since the grommet is not fixed to the bracket holder in the radial direction and the axial direction as described above, there is a problem in terms of workability. On the other hand, in the motor 1, a fitting groove portion (fitting portion) 43 is formed in the grommet 41, the fitting groove portion 43 is fitted into the grommet mounting portion 44 of the bracket holder 25, and the grommet 41 has a diameter. The displacement is stopped. For this reason, the grommet 41 is not in a state of being dangled, and workability when the bracket holder 25 to which the grommet 41 is attached is assembled to the bracket 8 is greatly improved.

  As shown in FIG. 3, the bracket holder 25 has a grommet mounting portion 44 formed in the outer peripheral wall 25a in order to attach the grommet 41 to the bracket holder 25. On both sides in the circumferential direction of the grommet mounting portion 44, end portions of the outer peripheral wall 25 a are erected as side wall portions (grommet holding portions) 45. When attaching the grommet 41 to the bracket holder 25, the grommet 41 is inserted into the grommet attaching portion 44 from above the bracket holder 25 as shown in FIG. 3. At this time, the side wall portion 45 of the bracket holder 25 and the bottom end portions 44 a of the grommet attachment portion 44 are inserted into the fitting groove portion 43, and the grommet 41 is fitted and attached to the grommet attachment portion 44.

  When the fitting groove 43 is fitted to the side wall 45 in this manner, the grommet 41 is attached to the grommet mounting portion 44 in a state where movement in the radial direction is restricted. In addition, by attaching the fitting groove 43 to the side wall 45, a labyrinth-like seal portion 46 is formed between the bracket holder 25 and the grommet 41. For this reason, compared with the grommet which does not have a fitting structure like the conventional brushless motor, the sealing performance inside the bracket holder 25 is improved.

  Further, as shown in FIG. 4, a convex portion 47 projects in the radial direction in the fitting groove portion 43. When the side wall 45 is inserted into the fitting groove 43, the convex portion 47 comes into contact with the side wall 45 and is pressed by the side wall 45. Thereby, the side wall 45 is held in the fitting groove 43 by the elastic force of the convex portion 47. Accordingly, it is difficult to come out in the axial direction (upward in FIGS. 3 and 4).

  After the grommet 41 is attached to the bracket holder 25, the lead wire 9 is pushed into the bracket holder 25 by a pressing piece 48 provided on the inner peripheral side of the grommet 41 as shown in FIG. That is, when the upper piece 48a of the pressing piece 48 is pushed downward in FIGS. 3 and 4, the lower end 48b is pushed down, and the lead wire 9 (see FIG. 4) extending below the lower end 48b is pushed downward. . As a result, the lead wire 9 is pushed into the lead wire accommodating portion 49 formed on the inner side of the side wall portion 45 of the bracket holder 25, and the efficiency of the wiring work is improved.

  Thus, in the motor 1 of the present invention, when the grommet 41 is attached to the bracket holder 25, the fitting groove 43 and the side wall 45 are fitted, and the grommet 41 is prevented from coming off in the radial direction with respect to the bracket holder 25. Is done. For this reason, the grommet 41 does not become unstable, the workability when assembling the bracket holder 25 to the bracket 8 is greatly improved, and the number of assembling steps can be reduced. Further, when the bracket holder 25 is assembled to the bracket 8, the lead wire 9 can be prevented from being bitten, the mounting failure of the grommet 41 can be reduced, and damage to the O-ring 42 during assembling can be suppressed. Product reliability is improved. In addition, since the grommet 41 is stably attached to the bracket holder 25, the misalignment between the two when transporting and delivering them in a pre-assembled state is reduced, and no reworking before assembly is required. Assembling man-hours can be reduced.

  Next, a brushless motor that is Embodiment 2 of the present invention will be described. 5 is a perspective view showing the configuration of a rubber grommet 51 (hereinafter abbreviated as grommet 51) used in the brushless motor of Example 2, FIG. 6 is a plan view thereof, and FIG. 7 is a bracket holder to which the grommet 51 is attached. 52 is a perspective view showing the configuration of 52. FIG. The brushless motor of the second embodiment has the same configuration as that of the motor 1 of the first embodiment except for the grommet 51. In this embodiment, the same members and parts as those of the first embodiment are the same. Reference numerals are assigned and description thereof is omitted.

  As shown in FIGS. 5 and 6, the O-ring is not integrally formed with the grommet 51 of the second embodiment. A mounting piece 53 projects from the inner peripheral surface 51b of the main body 51a in the radial direction. A fitting hole (fitting portion) 54 is formed through the center of the mounting piece 53 along the axial direction (vertical direction in FIG. 5). On the other hand, in order to attach the grommet 51 to the bracket holder 52, a grommet attaching portion 55 is formed in the outer peripheral wall 52a. As shown in FIG. 7, a fitting piece (grommet holding portion) 56 is erected at the center portion of the grommet mounting portion 55, and the circumferential dimension X1 of the fitting piece 56 is determined by the fitting of the grommet 51. The joint hole 54 is formed to have substantially the same dimension as the circumferential dimension X2.

  When attaching the grommet 51 to the bracket holder 25, the grommet 51 is inserted into the grommet attaching portion 55 from above the bracket holder 25 in the same manner as described above. At this time, the fitting piece 56 of the bracket holder 25 is inserted into the fitting hole 54, and the grommet 51 is fitted and attached to the grommet mounting portion 55. That is, in the brushless motor of the second embodiment, when the grommet 51 is attached to the bracket holder 25, the fitting piece 56 and the fitting hole 54 are fitted, and the grommet 51 is prevented from being displaced in the radial direction with respect to the bracket holder 25. The

  For this reason, also in the brushless motor according to the second embodiment, the grommet 51 is not in a state of being dangled, the workability when the bracket holder 25 is assembled to the bracket 8 is greatly improved, and the number of assembling steps can be reduced. Further, the lead wire 9 can be prevented from being bitten and the mounting failure of the grommet 51 can be reduced, and the product reliability can be improved. Furthermore, the gap between the grommet 51 and the bracket holder 25 at the time of conveyance and delivery is reduced, so that the rework before assembling becomes unnecessary, and the assembling man-hour can be reduced.

  It goes without saying that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention.

  For example, in the above-described embodiment, the brushless motor used for the column assist type EPS is shown. However, the present invention can be applied to other types of EPS motors. In addition, the present invention is widely applicable not only to EPS and motors for various on-vehicle electric products, but also to general brushless motors.

It is sectional drawing which shows the structure of the brushless motor which is Example 1 of this invention. It is a top view which shows the bracket holder of the state which attached the lead wire. It is a perspective view which shows the structure of a bracket holder and a grommet. It is a side view of a grommet. It is a perspective view which shows the structure of the rubber grommet used with the brushless motor which is Example 2 of this invention. It is a top view of the rubber grommet of FIG. It is a perspective view which shows the structure of the bracket holder with which a grommet is mounted | worn.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Brushless motor 2 Stator 3 Rotor 4 Case 5 Stator core 6 Stator coil 6a Coil end 7 Bus bar unit 8 Bracket 9 Lead wire 10 Lead wire insertion hole 11 Insulator 12 Feeding terminal 13 Rotor shaft 14a, 14b Bearing 15 Rotor core 16 Magnet 17 Magnet Holder 18 Magnet cover 21 Resolver 22 Rotor 23 Resolver stator 24 Resolver holder 24a Flange 25 Bracket holder (holder member)
25a outer peripheral wall 26 rib 27 female screw portion 28 mounting screw 29 power supply wiring 31 external power supply terminal 32 bus bar terminal 33 work hole 34 bracket cap 41 rubber grommet 42 O-ring 43 fitting groove (fitting portion)
44 Grommet mounting portion 44a Bottom end portion 45 Side wall portion (grommet holding portion)
46 Sealing portion 47 Protruding portion 48 Pressing piece 48a Upper piece portion 48b Lower end portion 49 Lead wire accommodating portion 51 Rubber grommet 51a Body portion 51b Inner peripheral surface 52 Bracket holder 52a Outer peripheral wall 53 Mounting piece 54 Fitting hole (fitting portion)
55 Grommet mounting part 56 Fitting piece (Grommet holding part)
X1 Mating piece circumferential dimension X2 Mating hole circumferential dimension

Claims (3)

A holder member to which a rotation detection device for detecting the rotation position of the rotor is attached; and a grommet that is attached to a grommet attachment portion formed on the holder member and into which a lead wire connected to the rotation detection device is inserted. A brushless motor,
The grommet includes a fitting portion that is fitted to the grommet holding portion provided in the grommet mounting portion, and is fitted to the grommet mounting portion in a state where movement of the grommet is restricted in a radial direction. Brushless motor.   2. The brushless motor according to claim 1, wherein the grommet holding portion is a side wall portion of the grommet mounting portion that is notched in an outer peripheral wall of the holder member, and the fitting portion is provided at a circumferential end portion of the grommet. A brushless motor, wherein the brushless motor is a fitting groove that is formed and can be fitted to the side wall.   2. The brushless motor according to claim 1, wherein the grommet holding portion is a fitting piece projecting from the grommet mounting portion formed in the outer peripheral wall of the holder member, and the fitting portion is formed on the grommet. A brushless motor, wherein the brushless motor is formed and is a fitting hole capable of fitting with the fitting piece.

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