JP2011250532A - Bus bar unit for brush motor, brush motor, and electric power steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce vibrations and operating noise caused in a brush motor that has a bus bar for supplying power to brushes and brush holder units supported by a floating structure.SOLUTION: A brush motor 10 includes a flange 12, a commutator 15, brushes 19, brush holder units 20, and a bus bar unit 30. The brushes 19 are arranged opposite to one another in a diametrical direction of the commutator 15 and in contact with the commutator 15. Each of the brush holder units 20 is mounted on the flange 12, with an elastic member 24 placed in between, so as to hold a corresponding one of the brushes 19. A bus bar unit 30 includes a bus bar and a resin portion 33. At least part of the bus bar is exposed from a casing of the brush motor 10, and supplies power to the brushes 19. The resin portion 33 is mounted on the flange 12, without the elastic member 24 placed in between, so as to hold the bus bar.

Description

  The present invention relates to a structure of a brush motor, and more particularly to a bus bar unit for a brush motor. Furthermore, the present invention relates to an electric power steering device equipped with a brush motor.

  As disclosed in Patent Document 1, a brush motor is a device in which a brush is brought into contact with a commutator to energize a coil, and the rotor is rotated by electromagnetic force. In such a brush motor, when vibration occurs when the rotor rotates, the vibration is applied to the commutator, the brush, the brush holder unit, and a member (particularly a flange) that is an outer shell of the brush motor. It is transmitted in order. Accordingly, in such a brush motor, when vibration occurs when the rotor rotates, an operation sound is generated due to the vibration. As a technique for reducing this vibration and operating noise, there is a structure in which the brush holder unit is floated. This structure is a structure in which an elastic member is interposed between a member serving as an outer shell of the brush motor and the brush holder unit. Hereinafter, this structure is referred to as a floating structure.

Japanese Patent Laying-Open No. 2003-070211 (FIG. 9) Utility Model Registration No. 3154393

  Some types of brush motors include a bus bar as in the technique disclosed in Patent Document 2, for example. The bus bar is a member for supplying electric power to the brush from the outside of the brush motor. If the floating structure is applied to a brush motor in which power is supplied to the brush by the bus bar, the brush motor is elastic for the floating structure by a screw for attaching the bus bar to a member (for example, a flange) serving as an outer shell of the brush motor. The member may be deformed.

  When the elastic member is deformed, the brush holder unit is tilted with respect to a member serving as an outer shell of the brush motor. Due to this inclination, such a brush motor creates a gap between the brush holder unit and the member that becomes the outer shell of the brush motor, or the gap becomes non-uniform. Since the brush may vibrate due to the gap, the brush motor may generate operating noise and vibration. Therefore, it is difficult to realize a floating structure with a brush motor in which electric power is supplied to the brush by the bus bar.

  The present invention has been made in view of the above, and an object of the present invention is to reduce vibration and operating noise generated in a brush motor in which power is supplied to a brush by a bus bar and the brush holder unit is supported by a floating structure. And

  In order to solve the above-described problems and achieve the object, a brush motor bus bar unit according to the present invention includes a housing, a rotor provided in the housing, and including a commutator and a core, and the housing. A brush holder unit provided inside the body and opposed to each other in the radial direction of the commutator; a brush held by the brush holder unit and provided in contact with the commutator; the housing and the brush A bus bar unit for a brush motor provided in a brush motor including an elastic member interposed between the holder unit and a bus bar that is at least partially exposed to the outside of the housing and supplies power to the brush And bus bar holding means that holds the bus bar and is attached to the casing without the elastic member between the bus bar and the casing. .

  By the said structure, the bus-bar unit for brush motors which concerns on this invention does not deform | transform the elastic member for floating structures provided in a brush motor. Therefore, the bus bar unit for a brush motor according to the present invention can reduce a possibility that a gap is generated between the brush holder unit and a member serving as an outer shell, or can reduce a possibility that the gap is not uniform. As a result, the bus bar unit for a brush motor according to the present invention can reduce operating noise and vibration due to the gap, and operating noise and vibration due to the gap becoming non-uniform.

  As a preferred aspect of the present invention, it is desirable that the bus bar holding means is attached to the housing together with the brush holder unit by one fastening means. With the above configuration, the brush motor bus bar unit according to the present invention is fastened together with the brush holder unit by one bolt. Thereby, the bus-bar unit for brush motors concerning this invention can reduce the number of volt | bolts required in order to attach a brush holder unit and self (brush-bar unit for brush motors) to the member used as an outer shell. Further, in general, the elastic member for the floating structure is provided avoiding the bolt hole for attaching the brush holder unit to the member serving as the outer shell. Therefore, the bus bar unit for a brush motor according to the present invention is disposed at a position that naturally avoids the elastic member by being fastened together with the brush holder unit by one bolt.

  As a preferred aspect of the present invention, it is desirable that the bus bar is connected to the brush via an electrically conductive member having flexibility. With the configuration described above, the brush motor bus bar unit according to the present invention is less likely to transmit vibration of the brush to itself (brush motor bus bar unit) because the electrically conductive member is less likely to transmit vibration. Further, with the configuration described above, the brush motor bus bar unit according to the present invention is capable of expanding an error allowed when attached to a member serving as an outer shell of the brush motor because the electrically conductive member bends. Also, with the above configuration, the bus bar unit for brush motor according to the present invention can be easily attached by a member that becomes an outer shell of the brush motor because the electric conductive member bends.

  In order to solve the above-described problems and achieve the object, a brush motor according to the present invention includes a housing, a rotor provided inside the housing, including a commutator and a core, and an interior of the housing. A brush holder unit that is provided to face the commutator in the radial direction; a brush that is held by the brush holder unit and provided in contact with the commutator; the housing and the brush holder unit; An elastic member interposed between the brush motor bus bar unit and the brush motor bus bar unit described above.

  With the above configuration, in the brush motor according to the present invention, deformation of the elastic member for the floating structure is reduced. Therefore, the brush motor according to the present invention can reduce the possibility that a gap is generated between the brush holder unit and the member serving as the outer shell, or can reduce the possibility that the gap becomes non-uniform. As a result, the brush motor according to the present invention can reduce the operating noise and vibration caused by the gap and the operating noise and vibration caused by the non-uniform gap.

  In order to solve the above-described problems and achieve the object, an electric power steering apparatus according to the present invention is characterized in that an auxiliary steering torque is obtained from the above-described brush motor.

  With the above configuration, in the electric power steering apparatus according to the present invention, deformation of the elastic member for the floating structure included in the brush motor is reduced. Therefore, the electric power steering device according to the present invention can reduce the possibility that a gap is generated between the brush holder unit and the member serving as the outer shell, or can reduce the possibility that the gap becomes non-uniform. As a result, the electric power steering apparatus according to the present invention can reduce the operating noise and vibration caused by the gap and the operating noise and vibration caused by the gap becoming non-uniform.

  The present invention can reduce vibration and operating noise generated in a brush motor in which power is supplied to the brush by the bus bar and the brush holder unit is supported by the floating structure.

FIG. 1 is a configuration diagram of an electric power steering apparatus including a brush motor. FIG. 2 is a front view for explaining an example of a reduction gear provided in the electric power steering device. FIG. 3 is an explanatory view schematically showing the brush motor cut along a plane orthogonal to the rotation axis. 4 is a cross-sectional view taken along the line AA in FIG. FIG. 5 is an explanatory view schematically showing a brush and a brush holder unit. FIG. 6 is an explanatory view schematically showing a brush case attached to a substrate. FIG. 7 is an explanatory view showing the elastic member cut along a plane orthogonal to the rotation axis. FIG. 8 is an explanatory diagram schematically showing the bus bar unit as viewed along the rotation axis direction. FIG. 9 is an explanatory diagram schematically showing the bus bar unit as seen along the circumferential direction.

  Hereinafter, the present invention will be described in detail with reference to the drawings. It should be noted that the present invention is not limited by the modes for carrying out the invention (hereinafter referred to as embodiments). In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art and those that are substantially the same. In the present embodiment, an example in which the brush motor according to the present invention is applied to an electric power steering device (EPS) will be described, but the application target of the present invention is not limited to the electric power steering device. Even when the present invention is applied to an electric power steering apparatus, the method is not limited.

(Embodiment)
FIG. 1 is a configuration diagram of an electric power steering apparatus including a brush motor. First, an outline of an electric power steering apparatus including the brush motor of the present embodiment will be described with reference to FIG. The electric power steering device 80 includes a steering wheel 81, a steering shaft 82, a steering force assist mechanism 83, a universal joint 84, a lower shaft 85, a universal joint 86, in the order in which the force applied from the steering wheel is transmitted. A pinion shaft 87, a steering gear 88, and a tie rod 89 are provided. The electric power steering device 80 includes an ECU (Electronic Control Unit) 90, a torque sensor 91a, and a vehicle speed sensor 91b.

  The steering shaft 82 includes an input shaft 82a and an output shaft 82b. The input shaft 82a has one end connected to the steering wheel 81 and the other end connected to the steering force assist mechanism 83 via the torque sensor 91a. The output shaft 82 b has one end connected to the steering force assist mechanism 83 and the other end connected to the universal joint 84. In the present embodiment, the input shaft 82a and the output shaft 82b are made of a magnetic material such as iron.

  The lower shaft 85 has one end connected to the universal joint 84 and the other end connected to the universal joint 86. The pinion shaft 87 has one end connected to the universal joint 86 and the other end connected to the steering gear 88. Steering gear 88 includes a pinion 88a and a rack 88b. The pinion 88a is connected to the pinion shaft 87. The rack 88b meshes with the pinion 88a. The steering gear 88 is configured as a rack and pinion type. The steering gear 88 converts the rotational motion transmitted to the pinion 88a into a linear motion by the rack 88b. The tie rod 89 is connected to the rack 88b.

  The steering force assist mechanism 83 includes a speed reducer 92 and the brush motor 10. The reduction gear 92 is connected to the output shaft 82b. The brush motor 10 is connected to the speed reducer 92 and generates auxiliary steering torque. In the electric power steering device 80, a steering column is constituted by the steering shaft 82, the torque sensor 91a, and the speed reducer 92. The brush motor 10 gives auxiliary steering torque to the output shaft 82b of the steering column. That is, the electric power steering apparatus 80 of this embodiment is a column assist system.

  FIG. 2 is a front view for explaining an example of a reduction gear provided in the electric power steering device. FIG. 2 shows a part in cross section. The speed reducer 92 is a worm speed reducer. The reduction gear 92 includes a reduction gear housing 93, a worm 94, a ball bearing 95 a, a ball bearing 95 b, a worm wheel 96, and a holder 97. The worm 94 is coupled to the shaft 18 of the brush motor 10 by a spline or an elastic coupling. The worm 94 is held in the speed reducer housing 93 so as to be rotatable by a ball bearing 95 a and a ball bearing 95 b held by the holder 97. The worm wheel 96 is rotatably held by the speed reducer housing 93. The worm teeth 94 a formed on a part of the worm 94 mesh with the worm wheel teeth 96 a formed on the worm wheel 96. The rotational force of the brush motor 10 is transmitted to the worm wheel 96 through the worm 94 to rotate the worm wheel 96. The reduction gear 92 increases the torque of the brush motor 10 by the worm 94 and the worm wheel 96. Then, the reduction gear 92 gives an auxiliary steering torque to the output shaft 82b of the steering column shown in FIG.

  The torque sensor 91a shown in FIG. 1 detects the driver's steering force transmitted to the input shaft 82a via the steering wheel 81 as a steering torque. The vehicle speed sensor 91b detects the traveling speed of the vehicle on which the electric power steering device 80 is mounted. The ECU 90 is electrically connected to the brush motor 10, the torque sensor 91a, and the vehicle speed sensor 91b. The ECU 90 controls the operation of the brush motor 10. Moreover, ECU90 acquires a signal from each of the torque sensor 91a and the vehicle speed sensor 91b. That is, the ECU 90 acquires the steering torque T from the torque sensor 91a, and acquires the traveling speed V of the vehicle from the vehicle speed sensor 91b. The ECU 90 is supplied with electric power from a power supply device (for example, a vehicle-mounted battery) 99 with the ignition switch 98 turned on. The ECU 90 calculates an assist steering command value of the assist command based on the steering torque T and the traveling speed V. Then, the ECU 90 adjusts the current value supplied to the brush motor 10 based on the calculated auxiliary steering command value.

  The steering force of the driver (driver) input to the steering wheel 81 is transmitted to the speed reduction device 92 of the steering force assist mechanism 83 via the input shaft 82a. At this time, the ECU 90 acquires the steering torque T input to the input shaft 82a from the torque sensor 91a, and acquires the traveling speed V from the vehicle speed sensor 91b. The ECU 90 controls the operation of the brush motor 10. The auxiliary steering torque created by the brush motor 10 is transmitted to the reduction gear 92. The steering torque (including auxiliary steering torque) output via the output shaft 82 b is transmitted to the lower shaft 85 via the universal joint 84 and further transmitted to the pinion shaft 87 via the universal joint 86. The steering force transmitted to the pinion shaft 87 is transmitted to the tie rod 89 via the steering gear 88 to steer the steered wheels. Next, the brush motor 10 will be described.

  FIG. 3 is an explanatory view schematically showing the brush motor cut along a plane orthogonal to the rotation axis. 4 is a cross-sectional view taken along the line AA in FIG. As shown in FIG. 4, the brush motor 10 includes a housing 11, a magnet 13, a rotor 14, a shaft 18, a brush 19, a brush holder unit 20, and a bus bar unit 30. The housing 11 includes a cylindrical portion 11a, a bottom portion 11b, and a flange 12. The cylindrical portion 11a is made of a magnetic material and has a substantially cylindrical shape. The magnetic material forming the cylindrical portion 11a is, for example, a general steel material such as SPCC (Steel Plate Cold Commercial) or electromagnetic soft iron. One end of the cylindrical portion 11a is closed by the bottom portion 11b. The bottom part 11b is formed integrally with the cylindrical part 11a, for example. Further, the opening which is the other end (the side opposite to the bottom 11 b) of the cylindrical portion 11 a is closed by the flange 12.

  The magnet 13 is attached to the inner surface of the cylindrical portion 11a by a magnet holder 13a. Two magnets 13 are provided. The two magnets 13 are provided with opposite polarities. The magnet 13 is covered with a magnet scattering prevention cover 13b. Thereby, the magnet scattering prevention cover 13b prevents the two magnets 13 from being accidentally scattered. The rotor 14 is provided in the cylindrical portion 11a. The rotor 14 is centered by a shaft 18 and is fixed to the shaft 18.

  Rotor 14 includes a commutator 15, a core 16, and a coil 17. In the commutator 15, a plurality of conductive portions 15 a formed of a conductor are arranged in parallel at equal intervals on the side surface of a cylindrical insulating portion formed of an insulator. The core 16 is formed using a magnetic material. The core 16 is formed by, for example, using a silicon steel plate as a magnetic material and laminating silicon steel plates. The core 16 portion of the rotor 14 has a plurality of slots (grooves). The coil 17 is wound around the slot. One end of the coil 17 is connected to one conductive portion 15a, and the other end is connected to another conductive portion 15a.

  The shaft 18 is supported by the bearing 18a and the bearing 18b so as to be able to rotate around the rotation axis Zr. The bearing 18 a is provided inside the cylindrical portion 11 a and at a substantially central portion of the flange 12. The bearing 18b is provided inside the cylindrical portion 11a and at a substantially central portion of the bottom portion 11b. The rotation axis Zr corresponds to the central axis of the shaft 18 and coincides with the rotation axis of the rotor 14. The shaft 18 is attached with a joint 18c. The worm 94 of the speed reducer 92 shown in FIG. 2 is splined to the joint 18c. The shaft 18 and the worm 94 may be coupled by an elastic coupling.

  The brush 19 is supported by a brush holder unit 20 described later. A plurality of brushes 19 are provided at positions facing the commutator 15 in the radial direction of the commutator 15 in the cylindrical portion 11a. The brush 19 is a polyhedron having a substantially prismatic shape, preferably a quadrangular prism shape. More preferably, the brush 19 has a shape in which one of the two apexes on the core 16 side protrudes out of the four apexes included on the surface facing the commutator 15 instead of the flange 12 side. The brush 19 is in contact with the commutator 15 at the protruding vertex. With such a structure, the brush motor 10 has a clear position where the brush 19 and the commutator 15 come into contact. As a result, the supply of electric power from the brush 19 to the commutator 15 is stabilized in the brush motor 10. Further, the user of the brush motor 10 can easily predict the wear state of the brush 19.

  The brush 19 is made of a material that has a small contact resistance and can withstand a mechanical shock. For example, the brush 19 is made of graphite. The brush 19 is supplied with power by the bus bar unit 30. The bus bar unit 30 will be described later. The electric power is electric power having a current value controlled by the ECU 90. The current supplied to the brush 19 is guided to the coil 17 through the conductive portion 15 a of the commutator 15 that is in contact with the brush 19. The current guided to the coil 17 passes through the coil 17, reaches another conductive portion 15 a of the commutator 15, and flows into another brush 19. The brush motor 10 generates a magnetic field when a current flows through the coil 17. In the brush motor 10, the rotor 14 is rotated by the interaction between this magnetic field and the magnetic field of the magnet 13.

  FIG. 5 is an explanatory view schematically showing a brush and a brush holder unit. As shown in FIG. 4, the brush holder unit 20 includes a brush case 21, a spring 22, a substrate 23, and an elastic member 24. The brush case 21 includes five plate-like portions, and is formed into a box shape having an opening 21f by the five plate-like portions. In FIG. 5, three of the five plate-like portions are shown. The remaining two plate-like portions are portions orthogonal to the three plate-like portions shown in FIG. 5, and are portions parallel to the paper surface in FIG.

  The brush case 21 is provided so that the opening 21 f faces the commutator 15 in the radial direction of the commutator 15. The brush case 21 is formed larger than the brush 19. This is because the brush 19 thermally expands in the brush case 21 when the temperature of the brush 19 rises. That is, the brush case 21 holds the brush 19 with a gap between itself (the brush case 21) and the brush 19.

  The spring 22 is a compression stress spring. The spring 22 is provided inside the brush case 21 and between the brush 19 and the brush case 21. In the present embodiment, the spring 22 is provided between the bottom surface portion of the five plate-like portions of the brush case 21 and the brush 19. The bottom surface portion is a plate-shaped portion on the side opposite to the opening 21 f among the five plate-shaped portions of the brush case 21. One end of the spring 22 is in contact with the bottom surface portion of the brush case 21, and the other end is in contact with the brush 19. As a result, the spring 22 applies a force in the direction toward the commutator 15 to the brush 19. Therefore, at least a part of the brush 19 protrudes from the opening 21 f and is pressed against the commutator 15 by the spring 22.

  FIG. 6 is an explanatory view schematically showing a brush case attached to a substrate. The substrate 23 is a member for attaching the brush case 21 to the flange 12. As illustrated in FIG. 4, the substrate 23 is provided between the brush case 21 and the flange 12. For example, two substrates 23 are provided as indicated by the hatched lines in FIG. The substrate 23 has, for example, a shape obtained by dividing an annular plate-shaped member into two. In the present embodiment, one substrate 23 has two brush cases 21 shown in FIG. Each substrate 23 includes a bolt through hole 23a. The bolt through hole 23 a is formed at a position facing the bolt hole 12 a formed in the flange 12. The bolt hole 12 a is a female screw hole for fastening the brush holder unit 20 to the flange 12. A bolt B as a fastening means shown in FIG. 4 is screwed into the bolt hole 12a. For example, two bolt holes 12a are provided. The board 23 is fastened to the flange 12 by the bolt B being inserted into the bolt through hole 23a and screwed into the bolt hole 12a.

  FIG. 7 is an explanatory view showing the elastic member cut along a plane orthogonal to the rotation axis. In the present embodiment, the elastic member 24 is provided along the circumferential direction around the rotation axis Zr, as indicated by the oblique lines in FIG. As described above, the plurality of brush cases 21 shown in FIG. 6 are arranged in the circumferential direction around the rotation axis Zr. The elastic member 24 is disposed along the plurality of brush cases 21. In the present embodiment, the elastic member 24 has a shape obtained by dividing an annular plate-shaped member into two parts. However, the elastic member 24 only needs to be interposed between at least the brush case 21 shown in FIG. 4 and the flange 12, and may have a shape obtained by, for example, dividing an annular plate-shaped member into four parts.

  The elastic member 24 is provided so as to avoid the bolt hole 12 a formed in the flange 12. As shown in FIG. 4, the elastic member 24 is provided between the substrate 23 and the flange 12. Thereby, the elastic member 24 implement | achieves what is called a floating structure, and reduces the vibration transmitted to the flange 12 from the brush case 21 via the board | substrate 23. FIG. Here, the flange 12 also has a cylindrical portion 12c, as shown in FIG. For example, the brush case 21 may be provided so as not to contact the cylindrical portion 12c of the flange 12 in the radial direction. Thereby, the brush motor 10 can further reduce vibration transmitted from the brush case 21 to the flange 12.

  FIG. 8 is an explanatory diagram schematically showing the bus bar unit as viewed along the rotation axis direction. FIG. 9 is an explanatory diagram schematically showing the bus bar unit as seen along the circumferential direction. As shown in FIGS. 8 and 9, the bus bar unit 30 includes a first bus bar 31, a second bus bar 32, a resin portion 33 as a bus bar holding means, a bolt through hole 34, and a pigtail 35. The first bus bar 31 and the second bus bar 32 are metal plate-like members. The first bus bar 31 and the second bus bar 32 are electrically conductive members. As shown in FIG. 8, the first bus bar 31 and the second bus bar 32 are provided at intervals so as not to contact each other. A part of the first bus bar 31 and the second bus bar 32 is exposed to the outside of the housing 11. A space surrounded by the cylindrical portion 11a, the bottom portion 11b, and the flange 12 is the inside of the housing 11, and a space other than the inside is the outside of the housing 11.

  The resin part 33 has elasticity, for example. The resin part 33 covers the first bus bar 31 and the second bus bar 32. Thereby, the resin part 33 insulates the first bus bar 31 and the second bus bar 32. Further, the resin portion 33 insulates the first bus bar 31 and the second bus bar 32 from the tubular portion 11 a and the flange 12 when the bus bar unit 30 is attached to the brush motor 10. As shown in FIG. 9, the bolt through hole 34 is a hole that penetrates the resin portion 33 in the direction of the rotation axis Zr. The bolt through hole 34 is formed in a portion of the resin portion 33 that is disposed inside the housing 11 illustrated in FIG. 4. Bolts B are inserted into the bolt through holes 34. The bolt through hole 34 is reinforced with, for example, a metal collar.

  The pigtail 35 is an electrically conductive member. The pigtail 35 electrically connects the first bus bar 31 and the second bus bar 32 shown in FIG. 8 and the brush holder unit 20 shown in FIGS. 4, 5, and 6. In the present embodiment, the pigtail 35 electrically connects the first bus bar 31 and the second bus bar 32 shown in FIG. The substrate 23 is provided with an electric circuit for supplying power to the brush 19. The electric circuit is electrically connected to the brush 19 by a wiring member 35a of an electric conductive member shown in FIG. Thereby, the brush 19 is supplied with electric power from the first bus bar 31 and the second bus bar 32 via the pigtail 35 and the substrate 23. The first bus bar 31 and the second bus bar 32 may be directly electrically connected to the brush 19 by the pigtail 35 without passing through an electric circuit formed on the substrate 23.

  The pigtail 35 is electrically connected to both the first bus bar 31 and the second bus bar 32 by, for example, welding, more specifically, projection welding. Further, the pigtail 35 is electrically connected to an electric circuit formed on the substrate 23 by, for example, welding, more specifically, projection welding. The pigtail 35 has flexibility. Since it has flexibility, the pigtail 35 is difficult to transmit vibration. Therefore, the brush motor 10 is unlikely to transmit the vibration of the brush 19 to the bus bar unit 30 via the substrate 23. Moreover, since the pigtail 35 bends, the brush motor 10 is likely to allow an attachment error between the bus bar unit 30 and the flange 12. Further, since the pigtail 35 bends in the brush motor 10, the bus bar unit 30 can be easily attached by the flange 12.

  Thus, since the pigtail 35 bends, the freedom degree of arrangement of the brush holder unit 20 and the bus bar unit 30 is improved in the brush motor 10. Therefore, a more preferable arrangement of the arrangement of the brush holder unit 20 and the bus bar unit 30 will be described. In the present embodiment, the bus bar unit 30 is provided so as to partially overlap the brush holder unit 20 in the direction of the rotation axis Zr, as shown in FIG. As a result, the brush motor 10 is larger in the radial direction by the area where the brush holder unit 20 and the bus bar unit 30 overlap than when the bus bar unit 30 is provided without overlapping the brush holder unit 20 in the direction of the rotation axis Zr. Can be reduced.

  Here, the flange 12 includes a bus bar unit mounting recess 12b as shown in FIG. 3, FIG. 6, and FIG. The resin portion 33 of the bus bar unit 30 is fitted into the bus bar unit mounting recess 12b. Thereby, the resin part 33 is interposed between the flange 12 and the cylindrical part 11a. And the resin part 33 is arrange | positioned in the position which avoided the elastic member 24 shown in FIG. That is, as shown in FIG. 4, the resin portion 33 is disposed at a position where the elastic member 24 is not interposed between itself (the resin portion 33) and the flange 12. Thereby, in the brush motor 10, the elastic member 24 is not interposed between the resin portion 33 and the flange 12.

  The bolt through hole 34 is provided at a position facing the bolt hole 12a shown in FIG. 7 in the direction of the rotation axis Zr. That is, in the brush motor 10 of this embodiment, as shown in FIG. 4, the bolt through holes 34, the bolt through holes 23 a, and the bolt holes 12 a are arranged in a line in the direction of the rotation axis Zr from the rotor 14 side. Be placed. In the brush motor 10, the bolt B is inserted into the bolt through hole 34, the bolt through hole 23a, and the bolt hole 12a from the rotor 14 side. Thereby, in the brush motor 10, the brush holder unit 20 and the bus bar unit 30 are fastened together by one bolt B.

  Here, in the conventional brush motor, if the elastic member is deformed, the brush holder unit is inclined due to the deformation. Specifically, the brush holder unit is inclined with respect to a plane orthogonal to the rotation axis Zr. Thereby, a clearance gap arises between a brush case and a flange, especially between the cylindrical part of a flange, and a brush case, or the said clearance gap becomes non-uniform | heterogenous. Further, since the brush is also tilted due to the deformation, the brush motor has unstable contact between the brush and the commutator. As a result, the brush motor may repeatedly collide with the brush case and the flange, increasing vibration and operating noise.

  However, in the brush motor 10 of this embodiment, the force that the bolt B applies to the brush holder unit 20 and the bus bar unit 30, that is, the force that presses the brush holder unit 20 and the bus bar unit 30 against the flange 12 is not transmitted to the elastic member 24. This is because the elastic member 24 is not interposed between the bus bar unit 30 and the flange 12 as described above. Thereby, the brush motor 10 can reduce the deformation of the elastic member 24. As a result, the brush motor 10 can reduce vibrations and operating sounds resulting from the deformation.

  In the brush motor 10 of the present embodiment, the brush holder unit 20 and the bus bar unit 30 are fastened together by one bolt B. Thereby, the brush motor 10 can reduce the number of bolts required for attaching the brush holder unit 20 and the bus bar unit 30 to the flange 12. Furthermore, the elastic member 24 needs to be provided avoiding the bolt hole 12a for attaching the brush holder unit 20 to the flange 12. Therefore, the brush motor 10 has a bus bar unit 30 and a bus bar unit 30 that are fastened together by a single bolt B, so that the bus bar can be used with a conventional structure, that is, without requiring a large-scale design change. The elastic member 24 is not interposed between the unit 30 and the flange 12.

  However, the brush motor 10 is not limited to a structure in which the brush holder unit 20 and the bus bar unit 30 are fastened together by one bolt B. The bus bar unit 30 may be attached to the flange 12 by, for example, a bolt different from the bolt for attaching the brush holder unit 20 to the flange 12. Even in this case, the brush motor 10 can reduce the deformation of the elastic member 24 as long as the elastic member 24 is not interposed between the bus bar unit 30 and the flange 12. As a result, the brush motor 10 can reduce vibrations and operating sounds resulting from the deformation.

  As described above, the brush motor bus bar unit, the brush motor, and the electric power steering apparatus according to the present invention have vibration generated in the brush motor in which power is supplied to the brush by the bus bar and the brush holder unit is supported by the floating structure. And it is useful for a technique for reducing operating noise.

DESCRIPTION OF SYMBOLS 10 Brush motor 11 Housing | casing 11a Cylindrical part 11b Bottom part 12 Flange 12a Bolt hole 12b Bus bar unit attachment recessed part 12c Cylindrical part 13 Magnet 13a Magnet holder 13b Magnet scattering prevention cover 14 Rotor 15 Commutator 15a Conductive part 16 Core 17 Coil 18 Shaft 18a Bearing 18b Bearing 18c Joint 19 Brush 20 Brush holder unit 21 Brush case 21f Open 22 Spring 23 Substrate 23a Bolt through hole 24 Elastic member 30 Bus bar unit 31 First bus bar 32 Second bus bar 33 Resin portion 34 Bolt through hole 35 Pigtail 35a Wiring member 80 Electric power steering device 81 Steering wheel 82 Steering shaft 82a Input shaft 82b Output shaft 83 Steering force assist Mechanism 84 universal joint 85 lower shaft 86 universal joint 87 the pinion shaft 88 steering gear 88a pinion 88b rack 89 tie rod 90 ECU
91a Torque sensor 91b Vehicle speed sensor 92 Deceleration device 93 Deceleration device housing 94 Worm 94a Worm tooth 95a Ball bearing 95b Ball bearing 96 Worm wheel 96a Worm wheel tooth 97 Holder 98 Ignition switch 99 Battery B Bolt Zr Rotating shaft

Claims (5)

A housing,
A rotor provided inside the housing and including a commutator and a core;
A brush holder unit that is provided inside the housing and is provided to face in the radial direction of the commutator;
A brush held by the brush holder unit and provided in contact with the commutator;
An elastic member interposed between the housing and the brush holder unit;
A brush motor bus bar unit provided in a brush motor including:
A bus bar that is at least partially exposed to the outside of the housing and supplies power to the brush;
Bus bar holding means for holding the bus bar and being attached to the casing without the elastic member between the casing and the casing;
A bus bar unit for a brush motor, comprising:   2. The brush motor bus bar unit according to claim 1, wherein the bus bar holding unit is attached to the housing together with the brush holder unit by one fastening unit.   The bus bar unit for a brush motor according to claim 1 or 2, wherein the bus bar is connected to the brush via a flexible electric conductive member. A housing,
A rotor provided inside the housing and including a commutator and a core;
A brush holder unit that is provided inside the housing and is provided to face in the radial direction of the commutator;
A brush held by the brush holder unit and provided in contact with the commutator;
An elastic member interposed between the housing and the brush holder unit;
A bus bar unit for a brush motor according to any one of claims 1 to 3,
A brush motor comprising:   An electric power steering apparatus, wherein an auxiliary steering torque is obtained from the brush motor according to claim 4.

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