JP2005269780A - Motor feeding brush, motor and electric power steering motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor feeding brush that can suppress the deterioration of performance caused by the movement of the motor feeding brush accompanied by the movement of a commutator, and to provide a motor equipped with the motor feeding brush, and an electric power steering motor. <P>SOLUTION: A tip 16b is composed of a normal rotation sliding face 16c and a reverse rotation sliding face 16d as sliding faces, and a tapered face 16e. An arc center O2 at normal rotation being the center of an arc that formes the normal rotation sliding face 16c is located in advance in a position that is shifted by an angle β that is equal to an angle α and advances in a direction opposite to the angle α with respect to a center line L1. An arc center O3 at reverse rotation being the center of an arc that formes the reverse rotation sliding face 16d is located in a position that is shifted by the angle α that is equal to the angle β and advances in a direction opposite to the angle β with respect to the center line L1. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a motor power supply brush pressed against a commutator, a motor including the motor power supply brush, and an electric power steering motor.

  2. Description of the Related Art Conventionally, there are brush devices that are disclosed in Patent Document 1 as brush devices provided in a DC motor. The brush device includes a substantially square cylindrical brush holder, a substantially rectangular parallelepiped motor power supply brush (hereinafter simply referred to as a brush) accommodated in the brush holder, and a coil spring that presses the brush toward the commutator side. It is configured.

By the way, when a DC motor having such a brush device is driven for a long time, the brush becomes hot and thermally expands due to contact resistance between the brush and the commutator. For this reason, the brush holder is designed in consideration of the thermal expansion of the brush. That is, the accommodation space in the brush holder is slightly larger than the brush before expansion, and there is a gap between the brush holder and the brush. By providing this gap, even if the brush becomes hot and thermally expands, the side wall of the brush holder is prevented from hindering the movement of the brush in the front-rear direction.
JP 2003-259607 A

  On the other hand, when the DC motor is driven, there is a gap between the brush holder and the brush, so that the brush is inclined in the brush holder due to friction between the outer peripheral surface of the commutator and the sliding surface of the brush. Move in parallel. As a result, the outer peripheral surface of the commutator and the sliding surface of the brush cannot be in good contact with each other, and power feeding becomes unstable and it may be difficult to obtain good performance.

  The present invention has been made in view of such circumstances, and its purpose is for motor power feeding that can suppress a decrease in performance caused by the motor power brush being moved by the commutator during rotation of the commutator. An object of the present invention is to provide a brush, a motor including the power feeding brush for the motor, and an electric power steering motor.

  In order to solve the above-mentioned problem, the invention according to claim 1 is accommodated in the brush holder with a gap between the brush holder and a side wall of the brush holder, and is urged toward the commutator in the brush holder. The motor power supply brush having a substantially rectangular parallelepiped shape in which the portion is slidably contacted with the outer peripheral surface of the commutator. An arc-shaped sliding surface is formed, and the sliding surface is inclined in the brush holder when the motor power supply brush slides with respect to a center line passing through the center of the circumferential width of the motor power supply brush. The motor power supply brush is formed in a central arc shape shifted in the direction opposite to the direction in which the motor power supply brush is inclined.

  The invention according to claim 2 is accommodated in the brush holder with a gap between the brush holder and a side wall of the brush holder, and is urged toward the commutator in the brush holder so that the tip end portion is an outer peripheral surface of the commutator. A substantially rectangular parallelepiped motor power supply brush that is slidably contacted with the motor, and a front end portion of the motor power supply brush has an arcuate sliding surface that is in sliding contact with the outer peripheral surface of the commutator and extends along the outer peripheral surface of the commutator. The sliding surface is parallelly moved in a direction perpendicular to the center line in the brush holder when the motor power supply brush slides from a center line passing through the center of the circumferential width of the motor power supply brush. It is formed in the shape of a circular arc at the center shifted by the gap in the direction opposite to the direction in which it moves.

  According to a third aspect of the present invention, in the motor power supply brush according to the first aspect, the motor power supply brush includes a power supply lead wire for supplying a motor drive current to the motor power supply brush. The lead wire is provided on the center line passing through the center of the circumferential width of the motor power supply brush.

  According to a fourth aspect of the present invention, in the motor power supply brush according to any one of the first to third aspects, the sliding surface is located on the center line of the circumferential width of the motor power supply brush. Two lines are formed symmetrically with respect to the line.

  According to a fifth aspect of the present invention, in the motor power supply brush according to any one of the first to fourth aspects, the tip portion of the motor power supply brush includes the sliding surface and the sliding surface. And a tapered surface away from the commutator along the axial direction from the axial end of the commutator.

  According to a sixth aspect of the present invention, in the motor power supply brush according to any one of the first to fourth aspects, the tip of the motor power supply brush has an axial direction of the commutator at the front end. A concave portion is formed in the central portion.

In a seventh aspect of the present invention, the motor includes the motor power supply brush according to any one of the first to sixth aspects.
According to an eighth aspect of the present invention, the electric power steering motor includes the motor power supply brush according to any one of the first to sixth aspects.

(Function)
According to the first aspect of the present invention, the sliding surface that is in sliding contact with the outer peripheral surface of the commutator is brushed when the motor power supply brush is in sliding contact with the center line that passes through the center of the circumferential width of the motor power supply brush. It is formed in a central arc shape shifted in the direction opposite to the direction in which the motor power supply brush is inclined by the angle of inclination in the holder. When the commutator rotates, the motor power supply brush is tilted by the commutator due to friction between the outer peripheral surface of the commutator and the sliding surface, and the center of the arc of the sliding surface moves by an angle formed by shifting in advance. As a result, the sliding surface faces the outer peripheral surface of the commutator in front, and the outer peripheral surface of the commutator and the sliding surface of the motor power supply brush are in good sliding contact. Accordingly, it is possible to suppress a decrease in performance caused by the motor power supply brush being moved by the commutator during rotation of the commutator.

  According to the second aspect of the present invention, the sliding surface that is in sliding contact with the outer peripheral surface of the commutator is located in the brush holder when the motor power supply brush slides from the center line passing through the center of the circumferential width of the motor power supply brush. Thus, it is formed in a circular arc shape with a center shifted by a gap in the direction opposite to the direction parallel to the direction perpendicular to the center line. When the commutator rotates, the power supply brush for the motor is moved in parallel by the friction between the outer peripheral surface of the commutator and the sliding surface, and the parallel movement is made by shifting the arc center of the sliding surface in advance. To do. As a result, the sliding surface faces the outer peripheral surface of the commutator in front, and the outer peripheral surface of the commutator and the sliding surface of the motor power supply brush are in good sliding contact. Accordingly, it is possible to suppress a decrease in performance caused by the motor power supply brush being moved by the commutator during rotation of the commutator.

  According to the third aspect of the present invention, since the power supply lead wire is small but rigid, the motor power supply brush is easily inclined with the power supply lead wire as the central axis when the commutator rotates. The center of the arc of the sliding surface is formed in a direction opposite to the tilting angle by an amount corresponding to the tilt angle of the motor power supply brush when sliding, with reference to the centerline to which the power supply lead wire is connected. Therefore, during sliding, the sliding surface of the motor power supply brush is slidably contacted with the outer peripheral surface of the commutator.

  According to the invention described in claim 4, since the two sliding surfaces are formed symmetrically with respect to the center line of the circumferential width of the motor power supply brush, In either case of rotation or reverse rotation, the outer peripheral surface of the commutator and the sliding surface of the motor power supply brush are in good sliding contact. Particularly, when the power supply lead wire is provided on the center line of the circumferential width of the motor power supply brush as in the invention described in claim 3, the amount by which the motor power supply brush is moved by the commutator. Since the forward rotation and the reverse rotation are substantially equal, the same performance can be obtained during the forward rotation and the reverse rotation.

  According to the fifth aspect of the present invention, since the sliding surface that is in sliding contact with the outer peripheral surface of the commutator is a part in the axial direction of the commutator at the tip of the motor power supply brush, the motor power supply brush is attached to the commutator. Accordingly, the outer peripheral surface of the commutator and the sliding surface can be in sliding contact with each other more satisfactorily. Further, since the tip of the motor power supply brush is composed of a sliding surface and a tapered surface along the axial direction of the commutator, the outer peripheral surface of the commutator and the sliding surface of the motor power supply brush come into contact with each other. The area is small. Therefore, the sliding noise is smaller than that of the motor power supply brush in which the entire tip is a sliding surface.

  According to the sixth aspect of the present invention, in the front end portion of the motor power supply brush, there are two sliding surfaces in sliding contact with the outer peripheral surface of the commutator at both ends of the front end portion along the axial direction of the commutator. Therefore, the motor power supply brush, especially the motor power supply brush that is long in the axial direction of the commutator, can stably slide the sliding surface against the outer peripheral surface of the commutator. Moreover, since the recessed part is formed in the center part of the axial direction of the commutator in a front-end | tip part, the area which the outer peripheral surface of a commutator and the electric power supply brush for motors contact is small. Accordingly, the sliding noise is smaller than that of the motor power supply brush in which the entire front end portion is in contact as a sliding surface.

According to the invention described in claim 7, the motor having the function described in any one of claims 1 to 6 is obtained.
According to the invention described in claim 8, an electric power steering motor having the function described in any one of claims 1 to 6 is obtained.

  ADVANTAGE OF THE INVENTION According to this invention, at the time of rotation of a commutator, the motor power supply brush by which the fall of the performance produced by a motor power supply brush being moved by a commutator is suppressed, a motor provided with this motor power supply brush, and electric power A steering motor can be provided.

(First embodiment)
A first embodiment embodying the present invention will be described below with reference to FIGS.
As shown in FIG. 1, an electric power steering motor (hereinafter referred to as EPS motor) 1 as a motor is fixed to a substantially bottomed cylindrical yoke housing 2, an end frame 3, and an inner peripheral surface of the yoke housing 2. The armature 5 and the brush device 6 accommodated in a space surrounded by the yoke housing 2 and the end frame 3 are provided.

A flange portion 2a extending radially outward is formed in the opening of the yoke housing 2, and a plurality of screw insertion holes 2b are formed in the flange portion 2a.
The end frame 3 is formed in a substantially disk shape, and a central hole 3a is formed at the center thereof. A fixing portion 3b extending toward the yoke housing 2 and extending radially outward is formed on the outer peripheral edge of the end frame 3, and the fixing portion 3b has a screw hole at a position corresponding to the screw insertion hole 2b. A plurality of 3c are formed. The end frame 3 is fixed to the yoke housing 2 by screws 7 that pass through the screw insertion holes 2b and are screwed into the screw holes 3c.

  The armature 5 includes a rotating shaft 8, a core 9 fixed to the rotating shaft 8, a winding 10 wound around the core 9, and a commutator 11 fixed to the rotating shaft 8 on the end frame 3 side. It has. The rotating shaft 8 is supported by a bearing 12 provided at the upper end at the center of the bottom of the yoke housing 2 and rotated at a lower end by a bearing 13 fixed to the inner periphery of the central hole 3a of the end frame 3. Held possible. Incidentally, the lower end side of the rotating shaft 8 protrudes outside from the central hole 3a while being rotatably supported by the bearing 13. And the fitting which has the two-surface width recessed part 14a for engaging with the external rotating shaft (this embodiment steering shaft) which is not illustrated in the lower end part of the protruding rotating shaft 8 so that it may engage with a rotation direction. The joint member 14 is fixed.

The commutator 11 has a substantially cylindrical shape, and is provided with a plurality of segments 11a on the outer peripheral surface thereof. The winding 10 is connected to each segment 11a.
The brush device 6 is disposed on the end frame 3 at a position adjacent to the commutator 11. A pair of brush devices 6 are provided at intervals of 180 degrees along the circumferential direction of the commutator 11. As shown in FIGS. 2A and 2B, each brush device 6 includes a brush holder 15, a brush 16, and a coil spring 17. In FIGS. 2A to 2C, the shapes of the brush holder 15 and the brush 16 constituting the brush device 6 are exaggerated to facilitate understanding.

  As shown in FIGS. 2 (a) and 2 (b), the brush holder 15 has a substantially rectangular tube shape with a bottom, and is fixed to the end frame 3 with the opening 15a facing the commutator 11 side. An extraction groove 15 c is formed in the upper side surface 15 b of the brush holder 15 along the longitudinal direction (the radial direction of the commutator 11 in the brush holder 15).

  The brush 16 has a substantially rectangular parallelepiped shape. The brush 16 is accommodated in the brush holder 15 between the side walls 15d and 15e of the brush holder 15 with a certain gap from the side walls 15d and 15e. This gap is provided in consideration of the thermal expansion of the brush 16 caused by the contact resistance between the brush 16 and the commutator 11 when the EPS motor 1 is driven for a long time. A coil spring 17 as a biasing means is disposed in a compressed state between the rear end surface 16a of one end in the longitudinal direction of the brush 16 and the bottom portion 15f of the brush holder 15. The brush 16 is urged toward the commutator 11 so that the distal end portion 16b contacts the outer peripheral surface (segment 11a) of the commutator 11.

  The tip 16b of the brush 16 is composed of a forward sliding surface 16c and a reverse sliding surface 16d as sliding surfaces, and a tapered surface 16e. The forward sliding surface 16c is in sliding contact with the segment 11a provided on the outer peripheral surface of the commutator 11 when the EPS motor 1 rotates forward. Further, the reverse sliding surface 16d is in sliding contact with the segment 11a of the commutator 11 when the EPS motor 1 rotates in reverse. In the present embodiment, the direction of the arrow X shown in FIG. 2A is the forward rotation direction, and the direction opposite to the arrow X is the reverse rotation direction. The forward sliding surface 16c and the reverse sliding surface 16d are formed on the upper end side in the axial direction of the commutator 11 at the distal end portion 16b side by side in the short direction of the brush 16. A tapered surface 16e is formed at the lower part of each sliding surface 16c, 16d. The taper surface 16e gradually moves away from the commutator 11 from the lower end of each sliding surface 16c, 16d downward in the axial direction of the commutator 11.

  Since the brush 16 is disposed with a gap between both side walls 15d and 15e of the brush holder 15, when the commutator 11 rotates and comes into sliding contact with the commutator 11, the segment 11a and the segment 11a Due to the friction generated between the front end 16b (forward sliding surface 16c and reverse sliding surface 16d) that is in contact with the side wall, it tilts until it contacts both side walls 15d and 15e. Accordingly, the forward sliding surface 16c and the reverse sliding surface 16d are formed in consideration of the amount by which the brush 16 is inclined. Specifically, the normal rotation sliding surface 16 c has an arc shape with the same curvature as the outer circumferential circle of the commutator 11. Here, when the EPS motor 1 rotates forward in the arrow X direction, the brush 16 is attached to the commutator 11 and is in contact with both side walls 15d and 15e of the brush holder 15 (shown by a two-dot chain line in FIG. 2A). Rotate slightly to position) and tilt. At this time, the center line L1 passing through the center of the commutator 11 in the brush 16 (the center of the circumferential width) passes through the center of the circumferential width of the brush holder 15 and passes through the center O1 of the outer peripheral circle of the commutator 11. The brush 16 is inclined with respect to the line L0 by an angle α rotated. Therefore, the normal rotation arc center O2 that is the center of the arc forming the normal rotation sliding surface 16c is previously equal to the angle α, and the angle α is an angle β that advances in the opposite direction to the center line L1. It is located at a shifted position. In other words, the forward-rotating sliding surface 16c is forwardly shifted with respect to the center line L1 by an angle α at which the brush 16 tilts in the brush holder 15 during the forward rotation of the EPS motor 1 in a direction opposite to the direction in which the brush 16 tilts. It is formed in a circular arc shape with the hour arc center O2. Therefore, when the EPS motor 1 rotates forward in the direction of the arrow X, the brush 16 rotates by the angle α by being driven by the commutator 11, so that the arc center O2 during forward rotation moves toward the center line L0 by the angle β. 11 substantially coincides with the center O1 of the outer circumference circle. As a result, the normal rotation sliding surface 16c comes into contact with the outer peripheral surface of the commutator 11 so as to face each other and come into surface contact (see FIG. 2C).

  The reverse sliding surface 16d also has an arc shape with the same curvature as the outer circumferential circle of the commutator 11, like the normal sliding surface 16c. Here, when the EPS motor 1 rotates in the reverse direction, the brush 16 is slightly rotated and tilted to a position where the brush 16 is brought into contact with the side walls 15d and 15e by the commutator 11. At this time, the center line L 1 of the circumferential width of the brush 16 is inclined by the angle β of the rotation of the brush 16 with respect to the center line L 0 of the circumferential width of the brush holder 15. Therefore, the reverse rotation arc center O3, which is the center of the arc forming the reversing sliding surface 16d, is previously shifted by an angle α that is equal to the angle β and that travels in the opposite direction to the center line L1. Located in position. In other words, the reverse rotation sliding surface 16d is a reverse rotation arc that is shifted in a direction opposite to the direction in which the brush 16 is inclined by an angle β that the brush 16 is inclined in the brush holder 15 when the EPS motor 1 is reverse with respect to the center line L1. It is formed in an arc shape with a center O3. Accordingly, when the EPS motor 1 rotates in the reverse direction, the brush 16 rotates by the angle β by the commutator 11, so that the arc center O3 during the reverse rotation moves toward the center line L0 by the angle α and the center of the outer circumference circle of the commutator 11. It almost coincides with O1. As a result, the reverse sliding surface 16d comes into contact with the outer peripheral surface of the commutator 11 so as to face each other and come into surface contact.

In the present embodiment, the forward sliding surface 16c and the reverse sliding surface 16d are formed symmetrically with respect to the center line L1.
On the upper surface 16 f of the brush 16, a pigtail 18 as a power supply lead wire is connected to the center line L <b> 1, and protrudes from the extraction groove 15 c formed in the brush holder 15 to the outside of the brush holder 15. The pigtail 18 is connected to a power source via a power supply terminal (not shown). Then, a drive current is supplied to the commutator 11 via the pigtail 18 and the brush 16, and the armature 5 of the EPS motor 1 is rotated forward or reverse.

As described above, the present embodiment has the following effects.
(1) The forward rotation sliding surface 16c that is in sliding contact with the outer peripheral surface of the commutator 11 is a forward arc that is shifted in the direction opposite to the direction in which the brush 16 is inclined by an angle α that is inclined in the brush holder 15 with respect to the center line L1. It is formed in an arc shape with a center O2. When the commutator 11 rotates forward, the brush 16 is tilted by the commutator 11 due to friction between the outer peripheral surface of the commutator 11 and the tip 16b, and the arc center O2 during forward rotation moves by an angle β formed by shifting in advance. . Then, since the curvature of the arc of the normal rotation sliding surface 16c is the same as the curvature of the outer circumference circle of the commutator 11, the arc center O2 during normal rotation overlaps the center O1 of the outer circumference circle of the commutator 11. Therefore, the normal sliding surface 16c comes to face the outer peripheral surface of the commutator 11 in front, and the outer peripheral surface of the commutator 11 and the normal sliding surface 16c can be in good sliding contact. As a result, it is possible to suppress a decrease in performance caused by the brush 16 being moved by the commutator 11 during normal rotation of the commutator 11. Further, with respect to the reverse sliding surface 16d, when the commutator 11 reverses, the same effect as the normal rotation sliding surface 16c has during forward rotation can be obtained. As described above, the phenomenon in which the brush 16 is moved by the commutator 11 is likely to occur particularly when the EPS motor 1 is new and is not familiar with the outer peripheral surface of the commutator 11. Easy to get effect.

  (2) On the upper surface 16f of the brush 16, the pigtail 18 is connected on the center line L1. In general, since the pigtail 18 is small but has rigidity, the pigtail 18 is easily inclined with the pigtail 18 as a central axis. In the present embodiment, the angles α and β are taken with respect to the center line L1, and the centers of the arcs of the sliding surfaces 16c and 16d are shifted by such angles α and β, respectively. 16d is formed. Therefore, when the commutator 11 rotates, the sliding surfaces 16c and 16d are slidably contacted with the outer peripheral surface of the commutator 11.

  (3) Since the sliding surface for forward rotation 16c and the sliding surface for reverse rotation 16d are formed symmetrically with respect to the center line L1 passing through the center of the circumferential width of the brush 16, this embodiment rotates forward and backward. In the EPS motor 1 of the embodiment, the outer peripheral surface of the commutator 11 and the sliding surfaces 16c and 16d are in good sliding contact with each other in both cases of normal rotation and reverse rotation. In particular, as in the present embodiment, when the pigtail 18 is formed on the center line L1 on the upper surface 16f of the brush 16, the amount of inclination (angle α, β) that the brush 16 is tilted by the commutator 11 is forward rotation. Therefore, the same performance can be obtained during forward rotation and reverse rotation.

  (4) The tip portion 16b is composed of a normal rotation sliding surface 16c, a reverse rotation sliding surface 16d, and a tapered surface 16e. Accordingly, the portion in sliding contact with the outer peripheral surface of the commutator 11 is one of the forward sliding surface 16c and the reverse sliding surface 16d in the axial direction of the commutator 11, that is, a part in the axial direction. 16 is easily moved by the commutator 11, and the outer peripheral surface of the commutator 11 can be slidably contacted with the forward sliding surface 16 c and the reverse sliding surface 16 d. Further, since the tip end portion 16b is composed of a normal rotation sliding surface 16c, a reverse rotation sliding surface 16d, and a tapered surface 16e, the outer peripheral surface of the commutator 11, the normal rotation sliding surface 16c, and the reverse rotation sliding surface. The area in contact with 16d is small. Accordingly, the sliding noise is smaller than that of the brush in contact with the entire surface in the axial direction of the tip portion 16b as the normal sliding surface 16c and the reverse sliding surface 16d.

(Second Embodiment)
In the first embodiment, the case where the brush 16 is rotated by the commutator 11 has been described. However, there is a case where the brush moves in parallel until it is brought into contact with the side wall 15d or the side wall 15e of the brush holder 15 by the commutator 11. Therefore, in the present embodiment, in the latter case, a second embodiment that embodies the present invention will be described with reference to FIG. In addition, about the structure similar to the said 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  In FIGS. 3A and 3B, the shapes of the brush holder 15 and the brush 22 constituting the brush device 21 are exaggerated to facilitate understanding. The brush device 21 of the present embodiment is disposed in the EPS motor 1 in place of the brush device 6 of the first embodiment. The brush 22 provided in the brush device 21 is obtained by changing the forward sliding surface 16c and the reverse sliding surface 16d in the brush 16 of the first embodiment. As shown in FIG. 3A, the brush 22 and the brush holder 15 are arranged between the side walls 15d and 15e and the brush 22 when the brush 22 is arranged at the center between both side walls 15d and 15e of the brush holder 15. The gaps G1 and G2 that are equal to each other are generated.

  The tip 22b of the brush 22 is composed of a forward sliding surface 22c and a reverse sliding surface 22d as sliding surfaces, and a tapered surface 16e similar to that of the first embodiment. The forward sliding surface 22c comes into sliding contact with the segment 11a provided on the outer peripheral surface of the commutator 11 when the EPS motor 1 rotates forward. Further, the reverse sliding surface 22d is in sliding contact with the segment 11a of the commutator 11 when the EPS motor 1 is reversely rotated. The forward rotation sliding surface 22c and the reverse rotation sliding surface 22d are formed on the upper end side in the axial direction of the commutator 11 at the distal end portion 22b side by side in the short direction of the brush 22.

  The forward rotation sliding surface 22 c has an arc shape with the same curvature as the outer circumferential circle of the commutator 11. Here, when the EPS motor 1 rotates forward in the direction of the arrow X, the brush 22 is attached to the commutator 11, and the side surface 22f of the brush 22 is brought into contact with the side wall 15d of the brush holder 15 (lower side in FIG. 3A). The brush 22 is translated in a direction perpendicular to the center line L2 passing through the center in the circumferential direction of the commutator 11 in the brush 22 up to the position (a position indicated by a two-dot chain line in FIG. 3A). At this time, the center line L2 of the circumferential width of the brush 22 is set to the side wall 15d by the gap G1 corresponding to the translation of the brush 22 relative to the center line L0 passing through the center of the circumferential width of the brush holder 15, that is, the distance Y1. Translate to the side. Therefore, the forward rotation arc center O4, which is the center of the arc forming the normal rotation sliding surface 22c, is previously equal to the gap G1 and is shifted from the gap G1 by a distance Y2 that travels in the opposite direction with respect to the center line L2. Located in. In other words, the forward rotation sliding surface 22c has a gap G1 in the direction opposite to the direction in which the brush 22 translates in the direction perpendicular to the center line L2 in the brush holder 15 from the center line L2 during the forward rotation of the EPS motor 1. Only, that is, formed in the arc shape of the arc center O4 during forward rotation shifted by the distance Y2. Therefore, as shown in FIG. 3B, when the EPS motor 1 rotates forward in the direction of the arrow X, the brush 22 moves in parallel by the distance Y1 due to the commutator 11, so that the arc center O4 during forward rotation has a distance Y2 And moves substantially toward the center line L0 and substantially coincides with the center O1 of the outer circumference circle of the commutator 11. As a result, the normal rotation sliding surface 22 c comes into contact with the outer peripheral surface of the commutator 11 in a face-to-face manner and comes into surface contact.

  The reverse sliding surface 22d also has an arc shape with the same curvature as the outer circumferential circle of the commutator 11, like the normal sliding surface 22c. Here, when the EPS motor 1 is rotated in the reverse direction, the brush 22 is moved by the commutator 11 to the position where the side surface 22g of the brush 22 contacts the side wall 15e of the brush holder 15 (upper side in FIG. 3A). Translate in a direction perpendicular to the line L2. At this time, the center line L2 of the brush 22 translates toward the side wall 15e by the gap G2 in which the brush 22 is translated relative to the center line L0, that is, Y2. Therefore, the reverse rotation arc center O5, which is the center of the arc forming the reversing sliding surface 22d, is previously equal to the gap G2 and is shifted from the gap G2 by a distance Y1 that travels in the opposite direction with respect to the center line L2. Be positioned. In other words, the reverse sliding surface 22d has a gap G2 in the direction opposite to the direction in which the brush 22 translates in the direction perpendicular to the center line L2 in the brush holder 15 from the center line L2 when the EPS motor 1 rotates backward. That is, it is formed in an arc shape of the arc center O5 during reverse rotation shifted by the distance Y1. Therefore, when the EPS motor 1 rotates in the reverse direction, the brush 22 is moved in parallel by the distance Y2 by the commutator 11. Therefore, the arc center O5 at the time of reverse rotation moves in the direction of the center line L0 by the distance Y1, and the outer circumferential circle of the commutator 11 moves. It substantially coincides with the center O1. As a result, the reversing sliding surface 22d comes into contact with the outer peripheral surface of the commutator 11 so as to face each other and come into surface contact.

In this embodiment, the forward sliding surface 22c and the reverse sliding surface 22d are formed symmetrically with respect to the center line L2.
As described above, according to this embodiment, in addition to the same effect as the effect (4) of the first embodiment, the following effect is obtained.

  (1) The forward sliding surface 22c has a gap G1 in the direction opposite to the direction in which the brush 22 moves parallel to the direction orthogonal to the center line L2 in the brush holder 15 from the center line L2, that is, the distance Y2. It is formed in an arc shape of the shifted arc center O4 during forward rotation. When the commutator 11 rotates forward, the brush 22 is moved by the commutator 11 in parallel with the commutator 11 due to the friction between the outer peripheral surface of the commutator 11 and the tip 22b, and the normal rotation arc center of the normal rotation sliding surface 22c. O4 moves in parallel by a distance Y2 formed in advance. Then, since the curvature of the arc of the normal rotation sliding surface 22c is the same as the curvature of the outer circumference circle of the commutator 11, the arc center O4 during normal rotation overlaps the center O1 of the outer circumference circle of the commutator 11. Accordingly, the normal rotation sliding surface 22c faces the outer peripheral surface of the commutator 11 in front, and the outer peripheral surface of the commutator 11 and the normal sliding surface 22c can be in good sliding contact. As a result, it is possible to suppress a decrease in performance caused by the brush 22 being moved by the commutator 11 during normal rotation of the commutator 11. Further, with respect to the reverse sliding surface 22d, when the commutator 11 reverses, the same effect as the normal rotation sliding surface 22c has during normal rotation can be obtained. As described above, the phenomenon in which the brush 22 is moved by the commutator 11 is likely to occur particularly when the EPS motor 1 is new and is not familiar with the outer peripheral surface of the commutator 11. Easy to obtain.

  (2) Since the forward sliding surface 22c and the reverse sliding surface 22d are formed symmetrically with respect to the center line L2 passing through the center of the circumferential width of the brush 22, the present embodiment rotates forward and backward. In the EPS motor 1, the outer peripheral surface of the commutator 11 and the sliding surfaces 22c and 22d are in good sliding contact with each other regardless of whether the rotation is forward or reverse.

In addition, you may change embodiment of this invention as follows.
In the first embodiment, the forward rotation sliding surface 16c and the reverse rotation sliding surface 16d are formed on the axial direction upper side (side to which the pigtail 18 is connected) of the commutator 11 at the distal end portion 16b. Although the taper surface 16e is formed in the lower part of 16c and the sliding surface 16d for reverse rotation, it is not restricted to this. A forward sliding surface 16c and a reverse sliding surface 16d are formed on the lower side in the axial direction of the commutator 11 (opposite the side where the pigtail 18 is connected), and the forward sliding surface 16c and the reverse sliding surface 16d. It is good also as a structure by which the taper surface 16e is formed in the upper part. Also in the second embodiment, the tapered surface 16e may be formed on the upper part (the side to which the pigtail 18 is connected) of the forward sliding surface 22c and the reverse sliding surface 22d.

  In the first embodiment, the forward rotation sliding surface 16c and the reverse rotation sliding surface 16d are formed on the axial direction upper side of the commutator 11 at the tip portion 16b, and the forward rotation sliding surface 16c and the reverse rotation sliding surface 16d Although the tapered surface 16e is formed in the lower part, the tapered surface 16e may be formed on both the upper and lower sides of the forward sliding surface 16c and the reverse sliding surface 16d. Also in the second embodiment, the tapered surfaces 16e may be formed on both the upper and lower sides in the axial direction of the forward sliding surface 22c and the reverse sliding surface 22d.

  In each of the embodiments described above, the forward end sliding surfaces 16c and 22c and the reverse rotation sliding surfaces 16d and 22d are formed on the tip portions 16b and 22b on the upper end side in the axial direction of the commutator 11 in the brushes 16 and 22, A tapered surface 16e is formed at the lower portion in the axial direction of each sliding surface 16c, 16d, 22c, 22d, but this is not restrictive. The entire tip portions 16b and 22b may be tapered surfaces 16e, and the sliding surfaces 16c and 16d or the sliding surfaces 22c and 22d may be formed on the tapered surfaces 16e. At that time, the sliding surfaces 16c, 16d, 22c, and 22d are continuously formed from the upper end to the lower end of the tapered surface 16e in the commutator axial direction.

  In the first embodiment, the tip end portion 16b is composed of the normal rotation sliding surface 16c, the reverse rotation sliding surface 16d, and the tapered surface 16e. In the second embodiment, the front end portion 22b is composed of the forward rotation sliding surface 22c, the reverse rotation sliding surface 22d, and the tapered surface 16e. However, the present invention is not limited to this, and the brushes 31 and 41 having the shapes shown in FIGS. 4 and 5 may be used.

  A tip 31 b of the brush 31 shown in FIG. 4 is formed in parallel with the outer peripheral surface of the commutator 11 in the axial direction of the commutator 11. Then, the forward sliding surface 16c and the reverse sliding surface 16d, or the forward sliding surface 22c and the reverse sliding surface 22d are formed continuously from the upper end to the lower end in the axial direction.

  The tip 41b of the brush 41 shown in FIG. 5 is formed with a recess 41c made of two inclined surfaces at the axial center of the commutator 11 in the brush 41. Then, at the both ends of the commutator 11 in the brush 41 in the axial direction, the normal rotation sliding surface 16c and the reverse rotation sliding surface 16d similar to the first embodiment, or the normal rotation sliding similar to the second embodiment, are provided. A moving surface 22c and a reverse sliding surface 16d are formed. If comprised in this way, in the front-end | tip part 41b, the sliding surfaces 16c and 16d (22c, 22d) which slidably contact with the outer peripheral surface of the commutator 11 will be two places of the both ends side along the axial direction of the commutator 11. Therefore, the brush 41 can stably slidably contact the sliding surfaces 16c and 16d (22c and 22d) with the outer peripheral surface of the commutator 11 (particularly when the brush 41 is long in the axial direction of the commutator 11). it can. Moreover, since the recessed part 41c is formed in the center part of the axial direction of the commutator 11 in the front-end | tip part 41b, the area where the outer peripheral surface of the commutator 11 and the front-end | tip part 41b contact is small. Accordingly, the sliding noise is smaller than that of a brush in which the entire tip is in contact as a sliding surface. In addition, although the brush 41 shown in FIG. 4 is provided with each sliding surface 16c, 16d (22c, 22d) in the axial direction both ends of the commutator 11 in the brush 41, it is not restricted to this. The front end portion 41b is composed of two inclined surfaces that form the concave portion 41c, and the normal rotation sliding surface 16c and the reverse rotation sliding surface 16d, or the normal rotation sliding surface 22c and the reverse rotation sliding surface are formed on the entire surface of each inclined surface, respectively. 16d may be formed.

  In each of the above embodiments, the pigtail 18 is connected to the center line L1 (L2) passing through the center of the circumferential width of the brush 16 (22) on the upper surface 16f of the brush 16 (22). Not limited to. When connecting to a location on the upper surface 16f that does not pass through the center line L1 (L2), the normal rotation sliding surface 16c and the reverse rotation sliding surface 16d, or the normal rotation sliding surface 22c and the reverse rotation sliding surface. The surface 22d may be formed symmetrically with respect to a straight line that is parallel to the center line L1 (L2) and passes through the connecting portion of the pigtail 18.

  In each of the above embodiments, the normal rotation sliding surfaces 16c and 22c and the reverse rotation sliding surfaces 16d and 22d are all formed in the same manner as the curvature of the outer circumference circle of the commutator 11, but may not be the same.

  In each of the above embodiments, the coil spring 17 is used as an urging means for urging the brushes 16 and 22 toward the commutator 11, but is not limited to the coil spring 17. In addition, any material that can urge the brush 16 toward the commutator 11, such as a bamboo spring, may be used.

  In the above embodiments, the brushes 16 and 22 are provided in the EPS motor 1, but the invention is not limited thereto, and may be provided in a motor having other brushes. In this case, the motor may be a motor that rotates only in one direction, instead of a motor that rotates both forward and reverse.

In each of the above embodiments, the brushes 16 and 22 are formed with the forward sliding surfaces 16c and 22c and the reverse sliding surfaces 16d and 22d, respectively. Alternatively, only one of the normal rotation sliding surfaces 16c and 22c and the reverse rotation sliding surfaces 16d and 22d may be formed.

The technical idea that can be grasped from each of the above embodiments will be described below.
(A) The motor power supply brush according to claim 1, wherein the motor power supply brush includes a power supply lead wire for supplying a motor drive current to the motor power supply brush on an upper surface of the motor power supply brush. The motor power supply brush is formed in two symmetrically with respect to a straight line parallel to the center line of the circumferential width of the motor power supply brush and passing through the power supply lead wire. In this case, since the power supply lead wire is small but rigid, the motor power supply brush is easily inclined with the power supply lead wire as the central axis. Therefore, the two sliding surfaces are in better contact with the outer peripheral surface of the commutator.

  (B) A brush for housing the motor power supply brush with a gap between the motor power supply brush whose tip is in sliding contact with the outer peripheral surface of the substantially cylindrical commutator and the side surface of the motor power supply brush. A brush device comprising a holder, an urging means for urging the brush toward the commutator, and a power supply lead wire for supplying a drive current of the motor to the brush, wherein the tip of the power supply brush for the motor Is formed in an arcuate sliding surface that is in sliding contact with the outer peripheral surface of the commutator and extends along the outer peripheral surface of the commutator, and the sliding surface is a center line that passes through the center of the circumferential width of the motor power supply brush. On the other hand, the motor power supply brush is formed in a central arc shape shifted in the direction opposite to the direction in which the motor power supply brush is inclined by an angle inclined in the brush holder at the time of sliding contact. Brush apparatus.

  (C) A brush that houses the motor power supply brush with a gap between the motor power supply brush whose tip is in sliding contact with the outer peripheral surface of the substantially cylindrical commutator and the side surface of the motor power supply brush. A brush device comprising a holder, an urging means for urging the brush toward the commutator, and a power supply lead wire for supplying a drive current of the motor to the brush, wherein the tip of the power supply brush for the motor Is formed in an arcuate sliding surface that is in sliding contact with the outer peripheral surface of the commutator and extends along the outer peripheral surface of the commutator, and the sliding surface is a center line that passes through the center of the circumferential width of the motor power supply brush. Thus, the motor power supply brush is formed in a central arc shape shifted by the gap in the direction opposite to the direction parallel to the direction perpendicular to the center line in the brush holder at the time of sliding contact. Brush and wherein.

Sectional drawing of the motor for electric power steering. (A) is a conceptual diagram showing the upper part of the brush device of the first embodiment, (b) is a conceptual diagram showing the side of the brush device of the first embodiment, (c) is the first implementation during the forward rotation of the EPS motor. The conceptual diagram which shows the brush apparatus of a form. (A) is the elements on larger scale of the brush apparatus of 2nd Embodiment, (b) is a conceptual diagram which shows the brush apparatus of 2nd Embodiment at the time of EPS motor normal rotation. The conceptual diagram which shows the side of the brush apparatus of another example. The conceptual diagram which shows the side of the brush apparatus of another example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Motor for electric power steering (EPS motor) as a motor, 11 ... Commutator, 15 ... Brush holder, 16, 22, 31, 41 ... Brush as power supply brush for motor, 15d, 15e ... Side wall, 16b, 22b, 31b, 41b ... tip, 16c, 22c ... forward rotation sliding surface as sliding surface, 16d, 22d ... reverse rotation sliding surface as sliding surface, 16e ... tapered surface, 16f ... upper surface, 18 ... for power feeding Pigtail as a lead wire, 41c ... concave portion, L1, L2 ... center line, α, β ... angle, O2, O4 ... center of arc during forward rotation as the center of arc of sliding surface, O3, O5 ... of sliding surface Arc center during reverse rotation as the center of the arc, G1, G2,...

Claims (8)

A substantially rectangular parallelepiped motor which is accommodated in the brush holder with a gap between the brush holder side wall and is urged toward the commutator in the brush holder so that the tip end portion is in sliding contact with the outer peripheral surface of the commutator. Power feeding brush for
The tip of the motor power supply brush is slidably contacted with the outer peripheral surface of the commutator, and an arcuate sliding surface is formed along the outer peripheral surface of the commutator.
The sliding surface is inclined with respect to a center line passing through the center of the circumferential width of the motor power supply brush by an angle that the motor power supply brush is inclined in the brush holder when slidingly contacted. A motor power supply brush characterized by being formed in a central arc shape shifted in the opposite direction to the direction. A substantially rectangular parallelepiped motor which is accommodated in the brush holder with a gap between the brush holder side wall and is urged toward the commutator in the brush holder so that the tip end portion is in sliding contact with the outer peripheral surface of the commutator. Power feeding brush for
The tip of the motor power supply brush is slidably contacted with the outer peripheral surface of the commutator, and an arcuate sliding surface is formed along the outer peripheral surface of the commutator.
The sliding surface is parallel to a direction perpendicular to the center line in the brush holder when the motor power supply brush slides from a center line passing through the center of the circumferential width of the motor power supply brush. Is formed in a circular arc shape with a center shifted in the opposite direction by the gap. The power supply brush for motor according to claim 1,
The motor power supply brush includes a power supply lead wire that supplies a motor drive current to the motor power supply brush.
The motor power supply brush, wherein the power supply lead wire is provided on the center line of the circumferential width of the motor power supply brush. The motor power supply brush according to any one of claims 1 to 3,
Two of the sliding surfaces are formed in line symmetry with respect to the center line of the circumferential width of the motor power supply brush. The power supply brush for motor according to any one of claims 1 to 4,
The front end portion of the motor power supply brush is configured by the sliding surface and a tapered surface that moves away from the commutator along the axial direction from the axial end of the commutator on the sliding surface. A power supply brush for a motor. The power supply brush for motor according to any one of claims 1 to 4,
The motor power supply brush is characterized in that a concave portion is formed at a tip portion of the motor power supply brush at a central portion of the tip portion in the axial direction of the commutator.   A motor comprising the motor power supply brush according to any one of claims 1 to 6.   An electric power steering motor comprising the motor power supply brush according to any one of claims 1 to 6.

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