JP2014239585A - Motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique for using a brush to a limit by securing a movable range of the brush, for preventing a shunt cable loosened by brush wear from being brought in contact with a commutator.SOLUTION: In the motor, a main body of a brush card includes a first projection 363 projecting in an axial direction on a side closer to a center axis than a shunt cable 33. At least part of a side wall of the first projection 363 simultaneously constitutes a wall face 367 of a guide way of the shunt cable 33 as well.

Description

  The present invention relates to a motor including a brush and a shunt cable.

  Conventionally, a structure having a partition wall that prevents a shunt cable connected to a brush from coming into contact with a commutator is known. For example, according to the structure described in Patent Document 1, even if the distance between the pigtail (shunt cable) and the commutator (commutator) is shortened due to wear of the brush, the partition prevents the pigtail from contacting the commutator. This can prevent damage to the pigtail.

  Further, a structure is known in which a brush holder is provided with a slit extending along the radial direction of the commutator. For example, according to the structure described in Patent Document 2, the brush can be used to the limit, and the life can be extended.

JP 2003-189551 A Japanese Patent No. 51255105

  Regardless of the structure described in Patent Document 1 or Patent Document 2, since the pigtail (shunt cable) is connected to the radially outer end of the brush, the pigtail was necessary before the brush was worn. The length becomes shorter as the brush wears. The length of the brush that is no longer needed becomes slack as the brush wears and is accommodated in a space in the brush assembly or brush holding plate.

  Here, in the structure described in Patent Document 1, since the slack of the pigtail generated when the distance between the pigtail and the commutator decreases as the brush wears, the movable range of the brush is limited. There is a problem that the brush cannot be used to the limit.

  On the other hand, in the structure described in Patent Document 2, there is no partition wall, and a slit extending along the radial direction of the commutator is provided. Therefore, the pigtail slack that occurs when the distance between the pigtail and the commutator becomes shorter due to wear of the brush is not pressed against the bulkhead, but the distance between the pigtail and commutator becomes smaller as the brush wears. There is a problem that the pigtail slack that occurs when it is shortened contacts the commutator, and the pigtail is damaged.

  The present invention has been made in view of the above problems, and is a technique for ensuring the movable range of the brush and using the brush to the limit, and preventing the slack of the shunt cable caused by brush wear from contacting the commutator. The purpose is to provide.

  According to the present invention, a shaft extending along a central axis, a rotor core fixed to the shaft, a coil in which a conducting wire is wound around the rotor core, and one axial end of the rotor core A rotating part that rotates around the central axis, a bottomed housing that has a substantially cylindrical shape around the central axis, and an inner peripheral surface of the housing; And a stationary portion having a magnet radially opposed to the outer peripheral surface of the rotor core, a bearing that rotatably supports the rotating portion, and is fixed to the housing, and penetrates in a central portion in an axial direction. A plate-like main body having a hole, a plurality of rod-shaped brushes disposed at a guide portion extending in a direction toward the central axis while being depressed in the axial direction in the main body, and having one end surface in contact with the commutator; Said A brush holder having a top plate portion covering the sheath, a shunt cable formed by knitting a conductive member and having a connection portion connected to a portion of the brush opposite to the central axis side, the shunt cable, and an external connection A brush card having a choke coil connected to a terminal, and a pressure member that has one end fixed to the main body and the other end pressed against the end surface of the brush opposite to the commutator. The main body has a first protrusion protruding in the axial direction on the central axis side of the shunt cable, and at least a part of the side wall of the first protrusion is At the same time, it constitutes a wall surface of the guide path of the shunt cable, and the guide path has a gap in which the vicinity of the connecting portion is accommodated in the side wall and the brush.

  According to the present invention, when the shunt cable moves toward the central axis along with the wear of the brush, the side wall of the first protrusion provided on the central axis side of the shunt cable in the brush card is the shunt cable. By acting as a guideway, the movement of the shunt cable can be regulated. Thereby, while allowing the brush to be worn to the maximum extent, it is possible to avoid problems such as contact with the commutator, which can be caused by the slack of the shunt cable caused by shortening the length of the brush.

It is sectional drawing which shows the motor in exemplary embodiment of this invention. It is a top view which shows the brush card | curd in exemplary embodiment of this invention. It is a perspective view showing the shunt cable periphery in an exemplary embodiment of the present invention. It is a perspective view which shows the brush holder in exemplary embodiment of this invention.

  Hereinafter, exemplary embodiments of the present invention will be described with reference to the drawings. In the present application, the direction parallel to the central axis of the motor is “axial direction”, the direction perpendicular to the central axis of the motor is “radial direction”, and the direction along the arc centered on the central axis of the motor is “circumferential direction”. , Respectively. Further, in the present application, the shape and positional relationship of each part will be described with the axial direction as the vertical direction and the brush holder side as the upper side with respect to the stator. However, the definition of the vertical direction is not intended to limit the orientation of the motor according to the present invention during manufacture and use.

  Further, in the present application, the “parallel direction” includes a substantially parallel direction. Further, in the present application, the “perpendicular direction” includes a substantially orthogonal direction.

  FIG. 1 is a diagram illustrating a cross section of a motor 1 in an exemplary embodiment of the invention. The motor 1 includes a rotating unit 2 and a stationary unit 4. The rotating part 2 is supported by the stationary part 4 via a bearing 5 so as to be rotatable.

  The rotating unit 2 includes a shaft 22 extending along a central axis A1, a rotor core 23 fixed to the shaft 22, a coil 21 in which a conducting wire is wound around the rotor core 23, and a shaft of the rotor core 23. A commutator 24 is provided that is fixed to the shaft 22 at one end in the direction.

  The stationary part 4 includes a bottomed housing 41 having a substantially cylindrical shape with the central axis A1 as a center, and a magnet 42 disposed on the inner peripheral surface of the housing 41 and opposed to the outer peripheral surface of the rotor core 23 in the radial direction. The brush card 3 is fixed to the lower end portion of the housing 41. The bearing 5 includes an upper bearing and a lower bearing. The upper bearing is held by the brush card 3, and the lower bearing is held by the housing 41.

  FIG. 2 is a top view showing the brush card 3 in the present embodiment. FIG. 3 is a perspective view showing the periphery of the shunt cable 33 in the present embodiment. Hereinafter, the detailed structure of the brush card 3 in the present embodiment will be described with reference to FIGS. 2 and 3.

  The brush card 3 includes a main body portion 36 made of a plate-shaped resin material, a plurality of rod-shaped brushes 31, a brush holder 32, a shunt cable 33 formed by knitting a conductive member, a shunt cable 33, and an external connection. A choke coil 34 connected to the terminal 37 and a pressure member 35 that presses the radially outer end face of the brush 31 are provided. The main body portion 36 has a disk shape in the present embodiment, and includes a hole 39 penetrating in the axial direction in the central portion thereof, and a guide portion 362 extending in the direction toward the central axis A1 while being recessed downward in the axial direction. Note that the shape of the main body 36 is not limited to a disk shape, and may be, for example, an elliptical shape or a substantially rectangular shape. The brush 31 is disposed in the guide portion 362 along the guide portion 362, and one end surface thereof is in contact with the commutator 24. The brush holder 32 includes a top plate portion 321 that covers at least a part of the brush 31. The shunt cable 33 has a connection portion 38 connected to a portion of the brush 31 opposite to the central axis side. In the present embodiment, the connecting portion 38 is provided on the side surface in the circumferential direction of the brush 31, but may be provided on the upper side surface in the axial direction of the brush 31 or may be provided on the radially outer end surface. The pressurizing member 35 has one end portion 351 held by the brush card 3 and the other end portion 352 is opposite to the contact surface of the commutator 24 of the brush 31, that is, by a wire that contacts the radially outer end surface. Composed. In this embodiment, the coil spring 353 is formed by winding a wire in a spiral shape, but is not limited to such a shape.

  As shown in FIG. 3, the main body 36 has a first protrusion 363 that protrudes in the axial direction on the center axis side of the shunt cable 33. In addition, the main body 36 has a second protrusion 364 on the opposite side in the circumferential direction across the first protrusion 363 and the brush 31. FIG. 3 shows a state in which the brush holder 32 is removed in order to make the first protrusion 363 and the second protrusion 364 easier to see than FIG. At least a part of the wall surface 367 of the first protrusion 363 also forms a wall surface 367 of the guide path 366 of the shunt cable 33 at the same time. That is, the portion of the wall surface 367 of the first protrusion 363 that can be in contact with the shunt cable 33 other than the center axis A1 side is the center axis A1 of the pressing member holding portion 365 that is radially outward from the first protrusion 363. Together with the side wall surface 367 and the side wall in the circumferential direction of the brush 31, an operating region of the shunt cable 33 is defined, and a guide path 366 of the shunt cable 33 is configured. The shunt cable 33 has a certain length between the connection portion 38 </ b> A with the choke coil 34 and the connection portion 38 with the brush 31. Here, since the connection part 38 of the shunt cable 33 and the brush 31 moves to the central axis A1 side as time passes, the shunt cable 33 itself also moves to the central axis A1 side as time passes. However, the physical distance between the connecting portion 38A of the choke coil 34 and the connecting portion 38 of the brush 31 is shortened as the brush 31 is worn, whereas the actual length of the shunt cable 33 is smaller than this physical distance. Because of the long length, the shunt cable 33 becomes slack with time. In the present embodiment, the wall surface 367 of the first protrusion 363 contacts the shunt cable 33 that moves toward the central axis A <b> 1 as the brush 31 is worn, and plays a role of absorbing such slack of the shunt cable 33. Therefore, the wall surface 367 of the first protrusion 363 restricts the movement of the shunt cable 33, so that the slack of the shunt cable 33 is eliminated, and the slack of the shunt cable 33, which has been a problem in the past, comes into contact with the commutator 24. It can be avoided.

  The guide path 366 may reach the hole 39 in the main body portion 36 of the brush card 3. That is, the guide path 366 may be open toward the central axis. By doing so, the connection portion 38 between the shunt cable 33 and the brush 31 can be as close to the commutator 24 as possible, and the wear of the brush 31 can be allowed to the maximum. In addition, in the guide path 366, at least the width between the wall surface 367 of the first protrusion 363 and the circumferential side wall of the brush 31 is not less than the width of the shunt cable 33 and not more than twice the width of the shunt cable 33. It is preferable. By doing so, even if the shunt cable 33 is slack, the slack is in the portion of the guide path 366 between the wall surface 367 of the first protrusion 363 and the side wall in the circumferential direction of the brush 31. There is no overlap in the width direction of the guide path 366, and clogging during movement of the shunt cable 33 in the guide path 366 due to looseness of the shunt cable 33 can be avoided.

  The wall surface 367 of the first projecting portion 363 is preferably substantially curved in the circumferential direction of the first projecting portion 363 at a portion that can contact the shunt cable 33 other than the central axis A1 side. By doing in this way, damage of the shunt cable 33 which contacted the 1st protrusion part 363 can be prevented.

  FIG. 4 is a perspective view showing the brush holder 32 in an exemplary embodiment of the invention.

  The brush holder 32 in the present embodiment includes a top plate portion 321, a plurality of leg portions 322, a pair of side wall portions 323, an arm portion 324, an engagement portion 326, and a stopper portion 325. The top plate portion 321 extends along the rod-shaped brush 31. The leg portion 322 extends downward in the axial direction from the top plate portion 321. The pair of side wall portions 323 extend in the longitudinal direction of the top plate portion 321 while projecting toward the lower side in the axial direction from both circumferential ends of the top plate portion 321. The arm portion 324 extends from the radially outer end of the side wall portion 323 opposite to the leg portion 322 with respect to the top plate portion 321 toward the outer side in the vertical direction of the side wall portion 323. The engaging portion 326 extends in the axial direction at the tip of the arm portion 324. The stopper portion 325 extends radially outward from the upper end in the axial direction of the engaging portion 326.

The first protrusion 363 crosses the first engagement hole 368 </ b> A opened toward the lower side in the axial direction at the upper end in the axial direction of the first protrusion 363 and the upper end in the axial direction of the first protrusion 363 in the circumferential direction. The slit 368 is cut in the axial direction and connected to the first engagement hole 368A. Further, the second protrusion 364 has a second engagement hole 368B opened toward the lower side in the axial direction at the upper end in the axial direction of the second protrusion 364. The arm portion 324 of the brush holder 32 is inserted into the slit 368 of the first projecting portion 363, and the engaging portion 326 of the brush holder 32 is inserted into the first engaging hole 368A of the first projecting portion 363, respectively. The lower surface of 325 is in contact with the upper surface in the axial direction of the first protrusion 363. At least one of the plurality of legs 322 of the brush holder 32 is inserted into the second engagement hole 368B of the second protrusion.

  Since the main body 36 of the brush card 3 is made of resin, it can be elastically deformed by an external stress. When such external stress is large, the deformation generated in the main body portion 36 is also transmitted to the top plate portion 321 of the brush holder 32, so that the top plate portion 3321 may come into contact with the brush 31, for example. The above-described engagement mechanism in the first protrusion 363, in particular, the presence of the slit 368 provided in the first protrusion 363 prevents the deformation of the main body 36 due to such external stress from being transmitted to the top plate 321. it can. That is, since the slit 368 is formed by being cut in the axial direction so as to cross the circumferential width of the first protrusion 363, the influence of external stress that can deform the main body 36 is affected by the brush holder 32. The arm portion 324 is absorbed by sliding in the slit 368 in the axial direction and the circumferential direction. Thereby, even if an external stress is applied, it is possible to avoid problems such as the top plate portion 321 contacting the brush 31 and damaging the brush 31.

  In the present embodiment, the guide path 366 of the shunt cable 33 has a portion defined by the wall portion 369 of the pressure member holding portion 365 and the side wall in the circumferential direction of the brush 31 that are radially outward from the first protrusion 363. The pressure member holding part 365 is configured to have an inclined surface that descends from the brush 31 side. The inclined surface may be curved in the axial direction or the radial direction at a part or all of the inclined surface.

  By configuring the guide path 366 of the shunt cable 33 in this way, the movement of the shunt cable 33 radially inward with the wear of the brush 31 is smoothly performed in the guide path 366, and the movement of the shunt cable 33 is controlled. It is possible to guide. Thereby, the malfunction which may arise at the time of the movement to the radial inside of the shunt cable 33 can be avoided effectively.

  As mentioned above, although exemplary embodiment of this invention was described, the structure of this invention is not limited to an above-described example. For example, you may combine suitably each element which appeared in each embodiment and its modification in the range which does not produce inconsistency.

  In addition, this invention can be used for the motor for anti-lock brakes, for example.

A1 Central axis 1 Motor 2 Rotating part 21 Coil 211 Winding 22 Shaft 23 Rotor core 24 Commutator 3 Brush card 31 Brush 32 Brush holder 321 Top plate part 322 Leg part 323 Side wall part 324 Arm part 325 Stopper part 326 Engagement part 327 End portion 33 Shunt cable 34 Choke coil 35 Pressure member 351 One end portion 352 Other end portion 353 Coil spring 36 Main body portion 362 Guide portion 363 First protrusion portion 364 Second protrusion portion 365 Pressure member holding portion 366 Guide portion 367 Wall surface 368 Slit 368A First engagement hole 368B Second engagement hole 369 Wall portion 37 External connection terminal 38 Connection portion with brush 38A Connection portion with choke coil 39 Hole 4 Stationary portion 41 Housing 42 Magnet 5 Bearing

Claims (5)

A shaft extending along a central axis, a rotor core fixed to the shaft, a coil formed by winding a conductive wire around the rotor core, and fixed to the shaft at one axial end of the rotor core A rotating part having a commutator and rotating about the central axis;
A stationary portion having a bottomed housing having a substantially cylindrical shape around the central axis, and a magnet disposed on an inner peripheral surface of the housing and opposed to the outer peripheral surface of the rotor core in a radial direction;
A bearing that rotatably supports the rotating portion and is fixed to the housing;
A plurality of plate-like main body portions each having a hole penetrating in the axial direction in the central portion and a guide portion extending in the direction toward the central axis while being depressed in the axial direction in the main body portion, and having one end surface in contact with the commutator A brush holder having a top plate portion covering at least a part of the brush, and a connecting portion formed by knitting a conductive member and connected to a portion of the brush opposite to the central axis side. A shunt cable, a choke coil connected to the shunt cable and an external connection terminal, and an end face opposite to the one end fixed to the main body and the other end contacting the commutator of the brush A pressure card that presses a brush card, and a motor comprising:
The main body has a first protrusion protruding in the axial direction on the central axis side than the shunt cable,
The motor in which at least a part of the side wall of the first projecting portion also constitutes the wall surface of the guide path of the shunt cable.   The motor according to claim 1, wherein the wall surface of the first protrusion is a substantially curved surface in a circumferential direction of the first protrusion. The brush holder protrudes from the top plate portion extending along the brush, a plurality of legs extending axially below the top plate portion, and axially downward from both circumferential ends of the top plate portion. However, a pair of side wall portions extending in the longitudinal direction of the top plate portion, and a radially outer end portion of the side wall portion on the opposite side of the leg portion with respect to the top plate portion, outward in the vertical direction of the side wall portion. An extending arm part, an engaging part extending in the axial direction at the tip of the arm part, and a stopper part extending radially outward from the axial upper end of the engaging part,
The first projecting portion traverses in the circumferential direction the first engagement hole opened toward the lower side in the axial direction at the upper end in the axial direction of the first projecting portion, and the upper end in the axial direction of the first projecting portion. The motor according to claim 1, further comprising: a slit cut in an axial direction and connected to the first engagement hole. The brush holder has a second protrusion on the opposite side in the circumferential direction across the first protrusion and the brush,
A second engagement hole opened downward in the axial direction at an upper end in the axial direction of the second protrusion, and the arm of the brush holder is formed in the slit of the first protrusion, The engaging portions are respectively inserted into the first engaging holes of the first projecting portion, the lower surface of the stopper portion of the brush holder is in contact with the upper surface in the axial direction of the first projecting portion, and the brush holder The motor according to claim 1, wherein at least one of the plurality of legs is inserted into the second engagement hole of the second protrusion.   The said guide path is the said brush from the said pressurization member holding part side in the site | part prescribed | regulated by the side wall of the pressurization member holding | maintenance part which exists in the radial direction outer side than the said 1st protrusion part, and the circumferential direction side wall of the said brush. The motor according to claim 1, wherein the motor has an inclined surface descending to the side.

Images