JP2008079466A - Brushless motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the reliability of a brushless motor by preventing sputter at a terminal welding portion from intruding into a motor. <P>SOLUTION: The brushless motor 1 comprises a bus bar unit 7 having a bus bar terminal 46, and a bracket holder unit 35 arranged contiguously to the bus bar unit 7 in the axial direction and having a terminal 44 connected with an external power supply. The bracket holder unit 35 has an opening 54 where the connection terminal 44 is arranged, and the bus bar terminal 46 is inserted into the opening 54 and secured to the connection terminal 44 by welding. In the proximity of the opening 54 between the bus bar unit 7 and the bracket holder unit 35, labyrinths 55 and 56 are formed by the bus bar unit 7 and the bracket holder unit 35 thus preventing sputter from intruding into the motor when the terminal is welded. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a brushless motor, and more particularly, to a structure for preventing spatter from occurring at a welded portion in a brushless motor.

  In recent years, in the brushless motor, from the viewpoint of improving assemblability, a method has been adopted in which each part of the motor is assembled and a plurality of assemblies are assembled to form one brushless motor. FIG. 6 is a cross-sectional view showing a configuration of a conventional brushless motor 100 (hereinafter abbreviated as “motor 100”). The motor 100 has a configuration in which a bracket assembly 101, a rotor assembly 102, and a stator assembly 103 are assembled. It has become. As shown in FIG. 6, the bracket assembly 101 has a configuration in which a bearing 105 and a resolver holder 107 to which a resolver stator 106 is attached are assembled to a bracket 104. The bracket 104 is provided with a connection terminal 108 that is electrically connected to an external power source.

The rotor assembly 102 includes a rotor 110 including a rotor shaft 109 and a resolver rotor 111 fixed to the rotor shaft 109, and is rotatably disposed in the stator assembly 103. Further, the stator assembly 103 includes a case 112, a stator core 113 fixed in the case 112, a motor coil 114 wound around the stator core 113, and a bus bar unit 115 attached to an end of the stator core 113. It has become. The bus bar unit 115 is provided with a bus bar terminal 116 electrically connected to the motor coil 114. The bus bar terminal 116 is pulled out from an opening 117 provided in the bracket 104, and is welded at a weld 118. The connection terminal 108 is fixed by welding.
JP 2006-33989 A

  However, since the motor 100 in FIG. 6 has a structure in which the bus bar terminal 116 and the connection terminal 108 are welded in the vicinity of the opening 117, if spatter is generated during welding, the spatter may enter the motor. There was a problem. As indicated by arrows in FIG. 6, when spatter is generated in the welded portion 118, the sputter may enter the inside of the bracket 104 from the opening 117 and adhere to the rotor 110 or the like inside the motor. Therefore, if spatter enters the motor, it may cause a motor failure, such as a problem in the rotational operation of the rotor 110, and a countermeasure has been demanded.

  An object of the present invention is to prevent spatter in the terminal welded portion from entering the motor and improve the reliability of the brushless motor.

  The brushless motor of the present invention is disposed on one end side of the stator core and includes a bus bar unit including a bus bar terminal electrically connected to the motor coil, and is disposed adjacent to the bus bar unit in the axial direction, and is electrically connected to an external power source. A bracket holder unit including a connection terminal connected to the bracket holder unit, the bracket holder unit including an opening in which the connection terminal is disposed, and the bus bar terminal includes the opening. A labyrinth part formed by the bus bar unit and the bracket holder unit is provided in the vicinity of the opening between the bus bar unit and the bracket holder unit. And

  In the present invention, a labyrinth portion is provided in the vicinity of the opening between the bus bar unit and the bracket holder unit, and a narrow portion in which sputtering is difficult to pass between the welded portion of the bus bar terminal and the connection terminal and the inside of the motor is constructed. . Thereby, even if spatter is generated during welding, the labyrinth portion prevents the spatter from entering the motor. Accordingly, it is possible to prevent a malfunction of the motor due to the intrusion of spatter, and to improve the reliability of the motor.

  In the brushless motor, in the labyrinth portion, a first labyrinth portion formed on the outer diameter side of the bus bar terminal and the connection terminal, and a second labyrinth formed on the inner diameter side of the bus bar terminal and the connection terminal. May be provided. In this case, the first labyrinth portion is pivoted on a first labyrinth wall projecting in an axial direction on an end surface of the bus bar unit on the bracket holder unit side, and on an end surface of the bracket holder unit on the bus bar unit side. You may form in the 2nd labyrinth wall which protrudes toward the direction and is arrange | positioned in parallel with the said 1st wall part at radial direction.

  In addition, the second labyrinth portion is projected in the axial direction at the base portion of the bus bar terminal, and a terminal holding portion having a tapered taper formed at the tip portion, and an inner edge of the opening portion. The outer peripheral surface may be formed by an edge portion that is a tapered surface facing the tapered portion of the terminal holding portion, and a linear portion is formed on the edge portion so as to face the flat bus bar terminal. It may be provided continuously.

  According to the brushless motor of the present invention, in a brushless motor having a bus bar unit including a bus bar terminal electrically connected to the stator coil and a bracket holder unit including a connection terminal electrically connected to an external power source, The bracket holder unit is provided with an opening in which the connection terminal is arranged, and the bus bar terminal is inserted into the opening to be welded and fixed to the connection terminal, and in the vicinity of the opening between the bus bar unit and the bracket holder unit. Since the labyrinth part is formed by the bracket holder unit, a narrow part where spatter does not easily pass between the welded part of the bus bar terminal and the connection terminal and the inside of the motor is constructed. It is possible to prevent entry. Therefore, it is possible to prevent a malfunction of the motor due to the intrusion of the spatter and to improve the reliability of the motor.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a sectional view of a brushless motor according to an embodiment of the present invention, and FIG. 2 is an exploded perspective view of the brushless motor of FIG. As shown in FIG. 1, a brushless motor 1 (hereinafter abbreviated as “motor 1”) is an inner rotor type brushless motor in which a stator 2 is arranged on the outside and a rotor 3 is arranged on the inside. 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 wound around the stator core 5 (hereinafter abbreviated as coil 6), and a bus bar unit (terminal unit) 7 attached to the stator core 5. It is configured. The case 4 is formed in a bottomed cylindrical shape with iron or the like, and a bracket 24 made of aluminum die cast is attached to an opening of the case 4 with a fixing screw 23. The stator core 5 includes a plurality of divided cores 8 and has a configuration in which nine divided cores 8 are assembled in the circumferential direction. The split core 8 is formed by stacking core pieces made of electromagnetic steel plates, and an insulator 9 made of synthetic resin is attached around the core.

  A coil 6 is wound around the outside of the insulator 9, 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 supply terminals 11 protrude in the radial direction, and when the bus bar unit 7 is attached, the coil end 6 a is welded to the power supply terminal 11. 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. 11 is electrically connected. After the bus bar unit 7 is attached, the stator core 5 is press-fitted into the case 4 and bonded and fixed to the inner peripheral surface of the case.

  A rotor 3 is inserted inside the stator 2. The rotor 3 has a rotor shaft 21, and the rotor shaft 21 is rotatably supported by bearings 22a and 22b. The bearing 22 a is fixed to the center of the bottom of the case 4, and the bearing 22 b is fixed to the center of the bracket 24. A cylindrical rotor core 25 is fixed to the rotor shaft 21, and a segment type magnet (permanent magnet) 26 is attached to the outer periphery thereof. A magnet holder 27 made of synthetic resin is inserted on the rotor shaft 21, and the magnet 26 is disposed on the outer periphery of the rotor core 25 in a form held by the magnet holder 27. In the motor 1, six magnets 26 are arranged along the circumferential direction, and a bottomed cylindrical magnet cover 28 is attached to the outside of the magnet 26.

  A rotor (resolver rotor) 32 of a resolver 31 serving as a rotation angle detection unit is attached to the end of the magnet holder 27. On the other hand, the stator (resolver stator) 33 of the resolver 31 is press-fitted into a metal resolver holder 34 and is fixed to the bracket holder unit 35 in that state. A sensor harness 36 for transmitting a signal output as the rotor 32 rotates is fixed to the resolver stator 33. The sensor harness 36 is welded to the terminal portion 33a of the stator 33, and an insulator 37 made of synthetic resin is attached to the terminal portion 33a. The sensor harness 36 is drawn between the bracket 24 and the bracket holder unit 35 along the circumferential direction, and is drawn out of the apparatus from the outer peripheral portion of the bracket 24 via the rubber grommet 38.

  In the motor 1, the resolver holder 34 is formed in a bottomed cylindrical shape, and is inserted and mounted in the central portion of the bracket holder unit 35. On the other hand, the opening side end portion where the flange portion 34 a is formed is lightly press-fitted into the outer periphery of the end portion of the rib 39 provided on the bracket 24. The rib 39 projects in a cylindrical shape toward the axial direction at the center of the bracket 24, and a bearing 22 b that supports the rotor shaft 21 is fixed to the inside of the rib 39. Therefore, by lightly press-fitting the resolver holder 34 into the rib 39, the resolver stator 33 is mounted concentrically with the rotor shaft 21, the core accuracy of the stator 33 and the rotor 32 of the resolver 31 is improved, and the rotor position detection accuracy is improved. Is planned.

  The bracket holder unit 35 is formed of a synthetic resin, and a metal female screw portion 41 is insert-molded. A mounting screw 42 is screwed into the female screw portion 41 from a resolver fixing hole 48 b provided in the bracket 24, whereby the resolver holder 34 is fixed inside the bracket 24. The attachment hole 34b formed in the flange portion 34a of the resolver holder 34 is a long hole extending in the circumferential direction, and the position of the resolver holder 34 can be finely adjusted in the circumferential direction. The bracket holder unit 35 is also provided with three external power feeding terminals 43. The external power supply terminal 43 is provided for each phase of U, V, and W, and when the bracket holder unit 35 is assembled to the bracket 24, the external power supply terminal 43 is provided so as to protrude in the radial direction from the side surface of the bracket 24. It has been.

  Each external power feeding terminal 43 (43U, 43V, 43W) is electrically connected to a connection terminal 44 (44U, 44V, 44W) provided in the bracket holder unit 35. Each connection terminal 44 protrudes from the main body 45 of the bracket holder unit 35 in the axial direction, and is welded to a bus bar terminal 46 (46U, 46V, 46W) provided on the bus bar unit 7. The bus bar terminal 46 also protrudes from the main body 47 of the bus bar unit 7 in the axial direction. When the motor 1 is assembled, the bus bar terminal 46 is formed on the bracket holder unit 35 and the connection terminal 44 is provided. It protrudes from the opening 54 in the axial direction and faces the connection terminal 44 in parallel. In the motor 1, after the bracket 24 is attached to the case 4, the bus bar terminal 46 and the connection terminal 44 are fixed by welding. A welding work hole 48a is formed in the bracket 24, and a bracket cap 49 is attached to the welding work hole 48a after the welding process.

  As described above, when the bus bar terminal 46 and the connection terminal 44 are fixed by welding, when spatter is generated and enters the motor, the motor operation may be hindered. On the other hand, in the motor 1, labyrinth portions 55 and 56 are formed in the vicinity of the opening 54 between the bus bar unit 7 and the bracket holder unit 35. Measures are taken so as not to enter. FIG. 3 is an explanatory view showing the configuration of the labyrinth portions 55 and 56, and FIG. 4 is an enlarged cross-sectional view of a portion of the bus bar unit 7 and the bracket holder unit 35 forming the labyrinth portions 55 and 56.

  As shown in FIGS. 3 and 4, a rabin rinse wall 57 (first labyrinth wall) is projected in the axial direction on the end face of the bus bar unit 7 on the bracket holder unit 35 side. On the other hand, the bracket holder unit 35 is provided with a rabin rinse wall 58 (second labyrinth wall) projecting in the axial direction on the end face on the bus bar unit 7 side. The rabin rinse wall 58 on the bracket holder unit 35 side is provided radially outside the rabin rinse wall 57 on the bus bar unit 7 side. When the bus bar unit 7 and the bracket holder unit 35 are assembled together, the outer peripheral surface of the rabin rinse wall 57 and the rabin rinse The wall 58 is opposed to the inner peripheral surface with a slight gap. At this time, the upper end surfaces of the labyrinth walls 57 and 58 also face the end surfaces of the bracket holder unit 35 and the bus bar unit 7 with a slight gap therebetween, thereby forming the labyrinth portion 55 (first labyrinth portion). Is done.

  On the other hand, on the end surface of the bus bar unit 7 on the bracket holder unit 35 side, a terminal holding portion 59 is projected from the base portion of the bus bar terminal 46 in the axial direction. A tip end portion of the terminal holding portion 59 has a tapered tapered detail 61. On the other hand, the bracket holder unit 35 is provided with an edge portion 62 that forms the inner edge of the opening 54, and the outer peripheral surface of the edge portion 62 is a tapered surface similar to the tapered portion 61 of the terminal holding portion 59. It has become. When the bus bar unit 7 and the bracket holder unit 35 are assembled, both tapered surfaces of the tapered portion 61 and the edge portion 62 face each other with a slight gap therebetween, and a labyrinth portion 56 (second labyrinth portion) is formed there.

  In this case, when assembling the unit, the gap between the outer edge of the edge 62 and the bus bar terminal 46 is kept small compared to the conventional motor (about 2 to 3 mm → 1 mm or less). Further, as shown in FIG. 5, the edge portion 62 has a shape in which three straight portions 63 are connected to the flat bus bar terminal 46, and the edge portion 62 is formed in an arc shape. Also, the maximum gap between the bus bar terminal 46 is set to be small. In other words, in the labyrinth portion 56, consideration is given to the gap between the tapered portion 61 and the tapered portion of the edge portion 62 as well as the gap at the entrance.

  As described above, in the motor 1, the labyrinth portions 55 and 56 are formed by the bracket holder unit 35 of the bus bar unit 7, and the narrow portion where sputtering is difficult to pass between the welded portion of the bus bar terminal 46 and the connection terminal 44 and the inside of the motor. Is building. For this reason, even if spatter is generated during welding, the labyrinth portions 55 and 56 are hindered from entering the motor, thereby preventing a malfunction of the motor due to the intrusion of spatter.

  Such a motor 1 is assembled as follows. First, the stator 2, the rotor 3, and the bracket assembly 51 are assembled individually. In this case, the bracket assembly 51 is an assembly product in which the bracket 24 in which the bearing 22 b is incorporated and the bracket holder unit 35 in which components related to the resolver stator 33 are assembled, and are fixed by a tapping screw 52. The stator 2 is an assembly product in which a bus bar unit 7 is attached to a stator core 5 around which a coil 6 is wound, and a power supply terminal 11 and a coil end 6 a are welded and accommodated in a case 4. The rotor 3 is an assembly product in which the rotor core 25 is fixed to the rotor shaft 21, the magnet holder 27 is attached, the magnet 26 is press-fitted and the magnet cover 28 is attached, and the resolver rotor 32 is press-fitted and fixed to the magnet holder 27. It is.

  After assembling such assemblies, the rotor 3 is attached to the bracket assembly 51, the stator 2 is externally mounted thereon, and the case 4 and the bracket 24 are fastened by the fixing screws 23. Next, the bus bar terminal 46 and the connection terminal 44 are welded and fixed via the welding work hole 48a. As described above, at this time, even if spatter is generated by welding, the spatter is blocked by the labyrinth portions 55 and 56 and does not enter the motor. In this state, motor resistance, insulation check, etc. are performed, and then the origin of the resolver 31 is adjusted. The origin adjustment is performed by finely adjusting the position of the resolver holder 34 from the outside of the bracket 24 in the circumferential direction by using the long attachment hole 34b. A resolver adjustment hole 48c is formed in the bracket 24, and the origin adjustment is performed from the resolver adjustment hole 48c. At that time, an adjusting jig (not shown) is inserted into the resolver adjusting hole 48c, the position of the resolver holder 34 is finely adjusted in the circumferential direction using the mounting hole 34b, and the origin of the resolver 31 is adjusted.

  After the origin is adjusted, the mounting screw 42 is inserted from the outside of the bracket 24 through the resolver fixing hole 48b, and is screwed and fixed to the female screw portion 41. As a result, the flange portion 34 a of the resolver holder 34 is fixed so as to be sandwiched between the bracket 24 and the bracket holder unit 35. After tightening the attachment screw 42, the bracket cap 49 is attached. Thus, the assembly work of the motor 1 is completed, after which various characteristic checks and the like are performed to obtain a finished product.

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 labyrinth wall 58 is provided on the outer side in the radial direction of the labyrinth wall 55 in the labyrinth portion 55. However, any of the labyrinth walls may be arranged on the outer side in the radial direction. It is also possible to build a double or triple labyrinth part by adding more labyrinth walls. Furthermore, it is also possible to form a labyrinth portion by projecting a rabin rinse wall in the radial direction.

  Furthermore, in the above-described embodiment, the brushless motor used in the column assist type EPS is shown, but the present invention can be applied to other types of EPS motors. In addition to EPS and various in-vehicle electric motors, the present invention can be widely applied to general brushless motors, and can also be applied to motors with brushes and electric devices.

It is sectional drawing of the brushless motor which is one Example of this invention. It is a disassembled perspective view of the brushless motor of FIG. It is explanatory drawing which shows the structure of a labyrinth part. It is an expanded sectional view of the site | part which forms the labyrinth part of a bus-bar unit and a bracket holder unit. It is explanatory drawing which shows the structure of an edge part. It is sectional drawing which shows the structure of the conventional brushless motor.

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 Divided core 9 Insulator 11 Feeding terminal 21 Rotor shaft 22a, 22b Bearing 23 Fixing screw 24 Bracket 25 Rotor core 26 Magnet 27 Magnet holder 28 Magnet cover 31 Resolver 32 Rotor 33 Stator 33a Terminal part 34 Resolver holder 34a Flange part 34b Mounting hole 35 Bracket holder unit 36 Sensor harness 37 Insulator 38 Rubber grommet 39 Rib 41 Female thread part 42 Mounting screw 43 External power supply terminal 44 Connection terminal 45 Main body Portion 46 Busbar terminal 47 Body 48a Welding hole 48b Resolver fixing hole 48c Resolver adjustment hole 49 Bracket cap 5 1 Bracket assembly 52 Tapping screw 54 Opening 55 Labyrinth part (first labyrinth part)
56 Labyrinth Club (2nd Labyrinth Club)
57 Labin rinse wall (1st labyrinth wall)
58 Labin rinse wall (2nd labyrinth wall)
59 Terminal holding part 61 Pointer 62 Edge part 63 Straight line part
100 brushless motor
101 Bracket assembly
102 Rotor assembly
103 Stator assembly
104 Bracket
105 Bearing
106 Resolver stator
107 Resolver holder
108 connection terminals
109 Rotor shaft
110 rotor
111 Resolver rotor
112 cases
113 Stator core
114 Motor coil
115 Busbar unit
116 Busbar terminal
117 opening
118 welds

Claims (5)

A bus bar unit having a bus bar terminal attached to one end side of the stator core and electrically connected to the stator coil, and a connection terminal that is arranged adjacent to the bus bar unit in the axial direction and is electrically connected to an external power source. A brushless motor having a bracket holder unit comprising:
The bracket holder unit includes an opening in which the connection terminal is disposed,
The bus bar terminal is inserted into the opening and welded to the connection terminal,
A brushless motor comprising a labyrinth portion formed by the bus bar unit and the bracket holder unit in the vicinity of the opening between the bus bar unit and the bracket holder unit.   2. The brushless motor according to claim 1, wherein the labyrinth portion is formed on the outer diameter side of the bus bar terminal and the connection terminal, and on the inner diameter side of the bus bar terminal and the connection terminal. And a second labyrinth portion.   3. The brushless motor according to claim 2, wherein the first labyrinth portion includes a first labyrinth wall projecting in an axial direction on an end surface of the bus bar unit on the bracket holder unit side, and the bus bar of the bracket holder unit. A brushless motor, comprising: a first labyrinth wall protruding in the axial direction on an end surface on a unit side and arranged in parallel in a radial direction.   3. The brushless motor according to claim 2, wherein the second labyrinth portion protrudes in the axial direction from a base portion of the bus bar terminal, and a terminal holding portion having a tapered tapered shape formed at a tip portion thereof, and the opening. A brushless motor, comprising: an inner edge of the portion, and an outer peripheral surface thereof having a tapered surface facing the tapered portion of the terminal holding portion.   5. The brushless motor according to claim 4, wherein the edge portion includes a linear portion continuously provided so as to face the flat bus bar terminal.

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