JP6984436B2 - Rotating machine - Google Patents

Description

The present invention relates to a rotary electric machine.

The rotary electric machine is equipped with an armature having a commutator, a brush whose tip is in sliding contact with the commutator, a brush holder for accommodating the brush, and a pressing member for pressing the rear end surface of the brush toward the commutator. DC motors are known (see, for example, Patent Document 1).

Japanese Patent No. 3653036

In such a rotary electric machine, when the brush vibrates as the brush comes into sliding contact with the commutator, the brush may collide with the brush holder and an abnormal noise may be generated.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a rotary electric machine capable of suppressing the generation of abnormal noise due to a brush colliding with a brush holder.

In order to solve the above problem, the rotary electric machine according to claim 1 has an armature having a commutator, a brush whose tip is in sliding contact with the commutator, and a pair of side wall portions and an upper wall portion. A brush holder for accommodating the brush, a pressing member for pressing the rear end surface of the brush toward the commutator side and the upper wall portion side, and a pair of side wall portions on the downstream side in the rotation direction of the armature. A protrusion formed by projecting from the lower part of the inner wall surface of the first side wall portion to be located and in contact with the lower part of the first side surface of the brush, and on the upper side of the protrusion portion, the inner wall surface of the first side wall portion and the said. It comprises a gap formed between the upper part of the first side surface of the brush and the brush.

In this rotary electric machine, the rear end surface of the brush is pressed toward the upper wall portion of the brush holder by the pressing member, so that the upper surface of the brush comes into contact with the upper wall portion of the brush holder. Further, when the armature is rotated, the rear end surface of the brush is pressed toward the commutator by the pressing member, so that the tip of the brush is in sliding contact with the commutator and in the tangential direction of the commutator acting on the brush. The brush is pressed against the side of the first side wall portion located on the downstream side in the rotation direction of the armature among the pair of side wall portions formed on the brush holder by the frictional force.

Here, even if the brush is pressed toward the first side wall portion, the first side surface of the brush does not come into contact with the entire inner wall surface of the first side wall portion due to a shape error during manufacturing of the brush, and the brush It is assumed that the upper part of the first side surface contacts the inner wall surface of the first side wall portion, and a gap is formed between the inner wall surface of the first side wall portion and the lower part of the first side surface portion of the brush. In this case, the lower end side of the brush is free while the upper surface of the brush is supported by the upper wall portion of the brush holder and the upper portion of the first side surface portion of the brush is supported by the inner wall surface portion of the first side wall portion. .. Therefore, when the brush receives frictional force from the commutator in the tangential direction, the lower end side of the brush vibrates significantly in the tangential direction of the commutator, and the brush collides with the brush holder, causing abnormal noise. There is a risk of becoming large.

However, according to this rotary electric machine, a protrusion that comes into contact with the lower part of the first side surface of the brush is formed on the inner wall surface of the first side wall portion of the pair of side wall portions located on the downstream side in the rotation direction of the armature. Has been done. Therefore, the upper surface of the brush is supported by the upper wall portion of the brush holder, and the lower portion of the first side surface of the brush is supported by the inner wall surface portion of the first side wall portion. Further, since a gap is formed between the inner wall surface of the first side wall portion and the upper portion of the first side surface portion of the brush, the lower portion of the first side surface portion of the brush is reliably supported by the inner wall surface of the first side wall portion. To. As a result, even if the armature rotates, the lower end side of the brush is supported by the inner wall surface of the first side wall portion, so that it is possible to suppress the lower end side of the brush from vibrating in the tangential direction of the commutator. As a result, it is possible to suppress the generation of abnormal noise due to the brush colliding with the brush holder.

By the way, the farther the protrusion (fulcrum), which is the contact portion between the first side surface of the brush and the inner wall surface of the first side wall portion, from the commutator, the longer the moment length of the tip of the brush from the protrusion. In this case, the vibration of the tip of the brush becomes large, and the lower tip side of the first side surface of the brush may collide with the first side wall portion to generate a loud noise.

Therefore, as described in claim 2, in the rotary electric machine according to claim 1, the protrusion comes into contact with the lower end side of the first side surface of the brush, and the gap is formed in the first side wall portion. It is preferable that the brush is formed between the inner wall surface and the upper end side of the first side surface of the brush.

According to this rotary electric machine, the protrusion comes into contact with the lower tip side of the first side surface of the brush, so that the moment length of the tip of the brush from the protrusion is shortened, so that the vibration of the tip of the brush is further effective. Can be suppressed. As a result, it is possible to suppress the generation of a large abnormal noise due to the lower tip side of the first side surface of the brush colliding with the first side wall portion.

As described in claim 3, in the rotary electric machine according to claim 2, the pressing member presses the rear end surface of the brush toward the first side wall portion, and the brush is the first. Supported by the first side wall portion at a first contact point where the lower end side of the side surface contacts the protrusion and a second contact point where the rear end of the first side surface contacts the inner wall surface of the first side wall portion. The central axis of the brush is inclined with respect to the central axis of the brush holder when viewed from above the brush holder, and the first contact point and the second contact point along the central axis of the brush holder are aligned with each other. When the distance between the brush holders is L and the distance between the first contact point and the second contact point along the direction orthogonal to the central axis of the brush holder in the top view of the brush holder is H, the above The inner wall surface of the first side wall portion is the upper surface view of the brush holder so that the arctan (H / L) is kept constant even if the tip of the brush is worn due to the sliding contact with the rectifier. It may be inclined with respect to the central axis of the brush holder.

According to this rotary electric machine, the inner wall surface of the first side wall is the brush holder so that the arctan (H / L) is kept constant even if the tip of the brush is worn due to the sliding contact with the commutator. It is tilted with respect to the central axis of the brush holder when viewed from above. Therefore, even if the tip of the brush is worn due to the sliding contact with the commutator, the tilt angle of the brush with respect to the central axis of the brush holder is maintained. As a result, the contact angle of the brush with respect to the commutator can be maintained even if the wear of the brush progresses.

Further, in order to solve the above-mentioned problem, the rotary armature according to claim 4 has an armature that has a commutator and rotates in both directions, a brush whose tip is in sliding contact with the commutator, and a pair of side wall portions. A brush holder having an upper wall portion and accommodating the brush, a pressing member for pressing the rear end surface of the brush toward the commutator side and the upper wall portion side, and the pair of side wall portions. The first side surface of the brush is formed so as to project from the lower part of the inner wall surface of the first side wall portion, and when the armature rotates in the first direction and the brush is pressed toward the first side wall portion. The inner wall surface of the first side wall and the inner wall surface of the first side wall on the upper side of the first protrusion in a state where the first protrusion is in contact with the lower portion and the first protrusion is in contact with the lower portion of the first side surface of the brush. The first gap formed between the upper part of the first side surface of the brush and the lower part of the inner wall surface of the second side wall portion of the pair of side wall portions are formed so that the armature projects in the second direction. When the brush is rotated and pressed toward the side of the second side wall, the second protrusion that comes into contact with the lower part of the second side surface of the brush and the second protrusion are the second side surface of the brush. in contact with the lower, the upper side of the second protruding portion comprises an inner wall surface of the second side wall portion, and a second gap formed between the upper portion of the second side of the brush.

According to this rotary electric machine, the rear end surface of the brush is pressed toward the upper wall portion of the brush holder by the pressing member, so that the upper surface of the brush comes into contact with the upper wall portion of the brush holder. Further, a first protrusion is formed on the inner wall surface of the first side wall portion of the pair of side wall portions, the armature rotates in the first direction, and the brush is pressed toward the first side wall portion. In this case, the first protrusion comes into contact with the lower part of the first side surface of the brush, so that the upper surface of the brush is supported by the upper wall part of the brush holder and the lower part of the first side surface of the brush is supported. It is in a state of being supported by the inner wall surface of the first side wall portion. Further, at this time, a gap is formed between the inner wall surface of the first side wall portion and the upper portion of the first side surface of the brush, so that the lower portion of the first side surface of the brush is surely on the inner wall surface of the first side wall portion. Is supported by. As a result, even if the armature rotates in the first direction, the lower end side of the brush is supported by the inner wall surface of the first side wall portion, so that it is possible to suppress the lower end side of the brush from vibrating in the tangential direction of the commutator.

Further, a second protrusion is formed on the inner wall surface of the second side wall portion of the pair of side wall portions, the armature rotates in the second direction, and the brush is pressed toward the second side wall portion. In this case, the second protrusion contacts the lower part of the second side surface of the brush, so that the upper surface of the brush is supported by the upper wall part of the brush holder and the lower part of the second side surface of the brush is supported. It is in a state of being supported by the inner wall surface of the second side wall portion. Further, at this time, a gap is formed between the inner wall surface of the second side wall portion and the upper portion of the second side surface portion of the brush, so that the lower portion of the second side surface portion of the brush is surely on the inner wall surface of the second side wall portion. Is supported by. As a result, even if the armature rotates in the second direction, the lower end side of the brush is supported by the inner wall surface of the second side wall portion, so that it is possible to suppress the lower end side of the brush from vibrating in the tangential direction of the commutator. From the above, when the armature rotates in either the first direction or the second direction, it is possible to suppress the generation of abnormal noise due to the brush colliding with the brush holder.

It is a perspective view of the rotary electric machine which concerns on 1st Embodiment of this invention. It is a vertical sectional view of the rotary electric machine of FIG. It is a figure which shows typically the brush holder of FIG. 2 and the peripheral part thereof. It is a figure which shows typically the support position of the brush by the brush holder of FIG. It is a bottom view which shows concretely the front housing of FIG. 5 is a cross-sectional view taken along the line F5-F5 of FIG. It is a figure which shows typically the brush holder and the peripheral part thereof when the armature rotates in the first direction in the 2nd Embodiment of this invention. It is a figure which shows typically the brush holder and the peripheral part thereof when the armature rotates in the 2nd direction in the 2nd Embodiment of this invention. It is a figure explaining the 3rd Embodiment of this invention together with the comparative example. It is a graph explaining the effect of the third embodiment of this invention. It is a figure which shows typically the brush holder which concerns on a comparative example, and the peripheral part thereof. It is a figure which shows the difference of the support position of the brush by the brush holder of FIG. 11 schematically. It is a figure explaining the measurement point of the vibration transmitted from the brush to the first side wall portion of a brush holder. It is a figure which shows the result by the measurement of FIG.

[First Embodiment]
First, the first embodiment of the present invention will be described.

The rotary electric machine 10 according to the first embodiment of the present invention shown in FIG. 1 is a DC motor with a brush. In FIG. 1 and each of the following figures, the arrow Z1 indicates one side in the axial direction of the rotary electric machine 10, and the arrow Z2 indicates the other side in the axial direction of the rotary electric machine 10. As shown in FIG. 2 (see also FIG. 1 as appropriate), the rotary electric machine 10 includes an armature 12, a yoke 14, a magnet 16, an end housing 18, and a brush device 20.

The armature 12 is a rotor and has a shaft 22, a core 24, a commutator 26, and a winding 28. The core 24 and the commutator 26 are fixed to the shaft 22. The tip end side of the shaft 22 is rotatably supported by a bearing 30 provided in the front housing 40 described later, and the rear end side of the shaft 22 is rotatably supported by a bearing 32 provided in the end housing 18 described later. It is supported. The winding 28 is wound around the core 24 and connected to the commutator 26. In the first embodiment, as an example, the armature 12 is specified to rotate only in the first direction.

The yoke 14 is formed in a cylindrical shape, and an armature 12 is rotatably housed inside the yoke 14. The magnet 16 is fixed to the inner peripheral surface of the yoke 14, and is arranged on the radial outer side of the core 24 so as to face the core 24. The end housing 18 is provided on the side of the yoke 14 opposite to the brush device 20, and closes the opening on the yoke 14 opposite to the brush device 20.

The brush device 20 has a plurality of brushes 34, a pressing member 36, a holding member 38, and a front housing 40. The front housing 40 is made of resin and has a housing main body 42 and a plurality of brush holders 44 (brush accommodating portions). The housing body 42 is provided on one side in the axial direction of the yoke 14, and closes an opening on one side in the axial direction of the yoke 14.

A concave bearing accommodating portion 46 for accommodating the above-mentioned bearing 30 is formed in the shaft core portion of the housing body 42. Further, the housing main body 42 is formed with an inclined portion 48 extending around the bearing accommodating portion 46. The inclined portion 48 is inclined with respect to the radial direction of the housing main body 42 so as to be toward the yoke 14 side toward the radial outer side of the housing main body 42 in the vertical cross-sectional view of the front housing 40.

The brush holder 44 is formed in a part of the housing body 42 in the circumferential direction, and bulges from the housing body 42 to the opposite side of the yoke 14. The brush holder 44 has a first side wall portion 50 and a second side wall portion 52 as a pair of side wall portions, and an upper wall portion 54 connecting the upper end portions of the first side wall portion 50 and the second side wall portion 52. (See Fig. 1). The brush holder 44 extends along the radial direction of the housing body 42.

The side of the brush holder 44 on the bearing accommodating portion 46 where the tip of the brush 34, which will be described later, is located is the tip end side of the brush holder 44, and the tip of the brush holder 44 is on the peripheral wall portion of the bearing accommodating portion 46. It is connected. Further, the brush holder 44 is generally inclined with respect to the radial direction of the housing main body 42 so as to be toward the yoke 14 side toward the radial outer side of the housing main body 42 in the vertical cross-sectional view of the front housing 40. See Figure 1).

The side of the brush holder 44 opposite to the bearing accommodating portion 46 and where the rear end surface of the brush 34 described later is located is the rear end side of the brush holder 44, and the rear end of the brush holder 44 is the front housing 40. It is located on the outer edge of the.

The brush 34 is housed in the brush holder 44 from the front end side to the rear end side thereof. The brush 34 is arranged radially outside the commutator 26, and the tip of the brush 34 is in contact with the outer peripheral surface of the commutator 26. The tip of the brush 34 is in sliding contact with the commutator 26 as the armature 12 rotates.

The holding member 38 is assembled to the brush holder 44 and has a lid portion 56 that closes the rear end opening of the brush holder 44. The pressing member 36 is, for example, a coil spring. The pressing member 36 is interposed between the brush 34 and the lid portion 56, and presses the brush 34 toward the commutator 26 against the lid portion 56.

By the way, as described at the beginning, in such a rotary electric machine 10, when the brush 34 vibrates due to the brush 34 sliding on the commutator 26, the brush 34 collides with the brush holder 44 and an abnormal noise is generated. It may occur. Therefore, in the first embodiment of the present invention, the following brush vibration damping structure is adopted. First, in order to clarify the superiority of the brush vibration damping structure according to the first embodiment of the present invention, the process leading to the invention of the brush vibration damping structure will be described.

11A and 11B are views schematically showing a brush holder 44 and its peripheral portion according to a comparative example, where FIG. 11A is a side view, FIG. 11B is a bottom view, and FIG. 11C is a rear view. In FIGS. 11A to 11C, the brush holder 44 is shown in cross section. In this comparative example, the configuration is the same as that of the first embodiment of the present invention except that the brush vibration damping structure described later is omitted from the first embodiment of the present invention.

The armature 12 including the commutator 26 rotates from the second side wall portion 52 toward the side of the first side wall portion 50 as an example of the first direction. Therefore, the first side wall portion 50 is located on the downstream side of the armature 12 in the rotational direction with respect to the second side wall portion 52.

Further, the brush 34 has a first side surface 34A, a second side surface 34B, an upper surface 34C, a lower surface 34D, and a rear end surface 34E. The rear end surface 34E of the brush 34 is formed with an inclined surface 34F that is inclined in a direction in which the brush 34 is pressed toward the upper wall portion 54 and the side of the first side wall portion 50 by the pressing member 36.

The inclined surface 34F is inclined with respect to the front-rear direction (arrow A direction) of the brush 34 so as to be toward the front side of the brush 34 toward the side of the second side wall portion 52 in the bottom view, and the upper wall portion in the side view. It is inclined with respect to the vertical direction (arrow B direction) of the brush 34 so as to be toward the rear side of the brush 34 toward the side of 54. Therefore, the brush 34 is pressed toward the upper wall portion 54 and the side of the first side wall portion 50 by pressing the inclined surface 34F by the pressing member 36.

12A and 12B are views schematically showing the difference in the support position of the brush 34 by the brush holder 44 of FIG. 11, FIG. 12A shows a design concept, and FIG. 12B shows a shape error in the brush 34 during manufacturing. Here is an example of the case. In the following description, the upper side of the brush 34 corresponds to the arrow Z1 side, and the lower side of the brush 34 corresponds to the arrow Z2 side.

As shown in the rear view of FIG. 12A, the design concept is that the first side surface 34A of the brush 34 comes into contact with the entire surface of the inner wall surface 50A of the first side wall portion 50. However, in reality, the brush 34 has a shape error at the time of manufacture. In the example shown in FIG. 12B, the brush 34 does not come into contact with the entire surface of the inner wall surface 50A of the first side wall portion 50 due to a shape error during manufacturing, so that the first side surface 34A of the brush 34 does not come into contact with the brush. The upper end side 34G of the first side surface 34A of the 34 comes into contact with the inner wall surface 50A of the first side wall portion 50, and the inner wall surface 50A of the first side wall portion 50 and the lower end side lower portion 34A of the first side surface 34A of the brush 34. A gap 58 is formed between them.

In this case, the upper surface 34C of the brush 34 is supported by the upper wall portion 54 of the brush holder 44, and the upper end side upper 34G of the first side surface 34A of the brush 34 is supported by the inner wall surface 50A of the first side wall portion 50. In this state, the lower end side of the brush 34 is in a free state. Therefore, when the brush 34 receives a frictional force in the tangential direction from the commutator 26, the lower end side of the brush 34 vibrates significantly in the tangential direction of the commutator 26, and the brush 34 collides with the brush holder 44. As a result, there is a risk that the abnormal noise will increase.

Further, as shown in the bottom view of FIG. 12, the contact portion 60 (fulcrum) between the first side surface 34A of the brush 34 and the inner wall surface 50A of the first side wall portion 50 becomes farther from the commutator 26 from the contact portion 60. moment length L _M of the tip of the brush 34 is lengthened. In this case, the vibration of the tip of the brush 34 becomes large, and the lower tip side lower portion 34H shown in the rear view of FIG. 12B may collide with the first side wall portion 50 to generate a loud abnormal noise. ..

Subsequently, the result of measuring the vibration of the brush 34 will be described. FIG. 13 is a diagram showing measurement points of vibration transmitted from the brush 34 to the first side wall portion 50 of the brush holder 44. In this measurement, as an example, vibration is measured using a non-contact type (laser type) vibration measuring instrument. The measurement point P1 corresponds to the upper tip side of the first side surface 34A of the brush 34, the measurement point P2 corresponds to the lower tip side of the first side surface 34A of the brush 34, and the measurement point P3 corresponds to the first of the brush 34. The measurement point P4 corresponds to the upper part on the rear end side of the side surface 34A, and corresponds to the lower part on the rear end side of the first side surface 34A of the brush 34.

FIG. 14 is a diagram showing the results of the measurements of FIG. As shown in FIG. 14, it can be seen that the vibration at the measurement point P2, that is, the lower portion on the tip end side of the first side surface 34A of the brush 34 is large.

Therefore, in the first embodiment of the present invention, the following brush vibration damping structure is adopted. 3A and 3B are views schematically showing a brush holder 44 and its peripheral portion according to the first embodiment of the present invention, where FIG. 3A is a side view, FIG. 3B is a bottom view, and FIG. 3C is a rear view. .. In FIGS. 3A to 3C, the brush holder 44 is shown in cross section.

As shown in FIG. 3, in the first embodiment of the present invention, the inner wall surface 50A of the first side wall portion 50 has a protrusion-like protrusion at a position corresponding to the tip end side lower portion 34H of the first side surface 34A of the brush 34. The portion 66 is formed so as to project. The protrusion 66 is in contact with the tip end side lower portion 34H of the first side surface 34A of the brush 34. Further, when the protrusion 66 comes into contact with the tip end side lower portion 34H of the first side surface 34A of the brush 34, between the inner wall surface 50A of the first side wall portion 50 and the tip end side upper portion 34G of the first side surface 34A of the brush 34. A gap 68 is formed in.

FIG. 4 is a diagram schematically showing a support position of the brush 34 by the brush holder 44 of FIG. As shown in FIG. 4, in the first embodiment of the present invention, the upper surface 34C of the brush 34 is supported by the upper wall portion 54 of the brush holder 44, and the lower end side 34H of the first side surface 34A of the brush 34 is supported. It is supported by the inner wall surface 50A (projection portion 66) of the first side wall portion 50. Further, a gap 68 is formed between the inner wall surface 50A of the first side wall portion 50 and the tip end side upper portion 34G of the first side surface 34A of the brush 34, whereby the tip end side lower portion of the first side surface 34A of the brush 34 is formed. 34H is reliably supported by the inner wall surface 50A of the first side wall portion 50.

Further, as described above, the protrusion 66 comes into contact with the tip end side lower portion 34H of the first side surface 34A of the brush 34, so that the protrusion 66 is from the contact portion 60 (projection 66) as shown in the bottom view of FIG. moment length L _M of the tip of the brush 34 is short.

5 is a bottom view specifically showing the front housing 40 of FIG. 2, and FIG. 6 is a sectional view taken along line F5-F5 of FIG. As shown in FIGS. 5 and 6, a protrusion 66 is formed on the inner wall surface 50A of the first side wall portion 50. The protrusion height H of the protrusion 66 with respect to the inner wall surface 50A of the first side wall 50 is, for example, about 0.15 mm.

Next, the operation and effect of the first embodiment of the present invention will be described.

As described in detail above, in the rotary electric machine 10 according to the first embodiment of the present invention, the rear end surface 34E of the brush 34 is pressed toward the upper wall portion 54 of the brush holder 44 by the pressing member 36, whereby the brush is brushed. The upper surface 34C of 34 comes into contact with the upper wall portion 54 of the brush holder 44. Further, when the armature 12 is rotated, the rear end surface 34E of the brush 34 is pressed toward the commutator 26 by the pressing member 36, so that the tip of the brush 34 slides into contact with the commutator 26 and acts on the commutator 34. Due to the frictional force in the tangential direction of the commutator 26 and the pressing force on the side of the first side wall portion 50 by the pressing member 36, the brush is applied to the side of the first side wall portion 50 located on the downstream side in the rotational direction of the armature 12. 34 is pressed.

Here, on the inner wall surface 50A of the first side wall portion 50 located on the downstream side in the rotation direction of the armature 12, a protrusion 66 that comes into contact with the tip end side lower portion 34H of the first side surface 34A of the brush 34 is formed. .. Therefore, in addition to the upper surface 34C of the brush 34 being supported by the upper wall portion 54 of the brush holder 44, the lower end side lower portion 34H of the first side surface 34A of the brush 34 is supported by the inner wall surface 50A of the first side wall portion 50. It becomes a state. Further, since a gap 68 is formed between the inner wall surface 50A of the first side wall portion 50 and the tip end side upper portion 34G of the first side surface 34A of the brush 34, the tip end side lower portion 34H of the first side surface 34A of the brush 34 is formed. Is reliably supported by the inner wall surface 50A of the first side wall portion 50.

As a result, even if the armature 12 rotates, the lower end side of the brush 34 is supported by the inner wall surface 50A of the first side wall portion 50, so that the lower end side of the brush 34 can be suppressed from vibrating in the tangential direction of the commutator 26. .. As a result, it is possible to suppress the generation of abnormal noise due to the brush 34 colliding with the brush holder 44.

In particular, the protrusion 66, by contact with the distal end side lower 34H of the first side surface 34A of the brush 34, since the moment length _{L M} of the tip of the brush 34 from the protruding portion 66 (contact portion 60) becomes shorter, brush The vibration at the tip of 34 can be suppressed more effectively. As a result, it is possible to suppress the generation of a large abnormal noise due to the collision of the tip side lower portion 34H of the first side surface 34A of the brush 34 with the first side wall portion 50.

Next, a modified example of the first embodiment of the present invention will be described.

In the first embodiment, more preferably, the protrusion 66 is formed on the inner wall surface 50A of the first side wall portion 50 of all the brush holders 44, but the plurality of brush holders 44 have the first side wall portion 50. The brush holder 44 on which the protrusion 66 is not formed may be included in the inner wall surface 50A.

Further, in the first embodiment, the inclined surface 34F formed on the rear end surface 34E of the brush 34 is more preferably such that the brush 34 is on the side of the upper wall portion 54 and the side of the first side wall portion 50 by the pressing member 36. Tilt in the direction of being pressed. However, the inclined surface 34F may be inclined in a direction in which the brush 34 is pressed only toward the upper wall portion 54 by the pressing member 36.

Further, in the first embodiment, more preferably, the protrusion 66 is formed at the end of the first side wall portion 50 on the commutator side 26 side corresponding to the tip end side lower portion 34H of the first side surface 34A of the brush 34. A gap 68 is formed between the inner wall surface 50A of the first side wall portion 50 and the tip end side upper portion 34G of the first side surface 34A of the brush 34. However, the protrusion 66 may be formed at any position in the front-rear direction of the first side wall portion 50 as long as it corresponds to the lower portion of the first side surface portion 34A of the brush 34. Further, the gap 68 may also be formed between the inner wall surface 50A of the first side wall portion 50 and the upper portion of the first side surface 34A of the brush 34, corresponding to the position of the protrusion 66.

It should be noted that the above-mentioned plurality of modifications may be carried out in combination as appropriate.

[Second Embodiment of the present invention]
Next, a second embodiment of the present invention will be described.

In the second embodiment of the present invention shown in FIGS. 7 and 8, the armature 12 is specified to rotate in both the first direction and the second direction as an example. FIG. 7 is a diagram schematically showing a brush holder 44 and its peripheral portion when the armature 12 rotates in the first direction in the second embodiment of the present invention, where (A) is a side view and (B). Is a bottom view and (C) is a rear view. 8A and 8B are views schematically showing the brush holder 44 and its peripheral portion when the armature 12 rotates in the second direction in the second embodiment of the present invention, and FIG. 8A is a side view, (A). B) is a bottom view, and (C) is a rear view. In FIGS. 7A to 7C and FIGS. 8A to 8C, the brush holder 44 is shown in cross section.

In the second embodiment of the present invention, the configuration is changed as follows with respect to the first embodiment of the present invention described above. That is, in the second embodiment of the present invention, the second side wall portion 52 of the brush holder 44 is configured symmetrically with the first side wall portion 50 in response to the rotation of the armature 12 in both directions. The second side wall portion 52 is formed with a protrusion 76 similar to the protrusion 66 of the first side wall portion 50.

The protrusion 66 of the first side wall portion 50 is an example of the "first protrusion portion" in the present invention, and the protrusion 76 of the second side wall portion 52 is an example of the "second protrusion portion" in the present invention. As shown in FIG. 7, the protrusion 66 is formed so as to project from the inner wall surface 50A of the first side wall portion 50, and is in contact with the tip end side lower portion 34H of the first side surface 34A of the brush 34. Further, as shown in FIG. 8, the protrusion 76 is formed so as to project from the inner wall surface 52A of the second side wall portion 52, and is in contact with the tip end side lower portion 34I of the second side surface 34B of the brush 34.

In this first modification, as shown in FIG. 7, when the armature 12 rotates in the first direction, the frictional force in the tangential direction of the commutator 26 acting on the brush 34 and the first side wall portion by the pressing member 36 The pressing force toward the 50 side presses the brush 34 toward the first side wall portion 50, and the protrusion 66 comes into contact with the tip end side lower portion 34H of the first side surface 34A of the brush 34. Further, in the state where the protrusion 66 is in contact with the tip side lower portion 34H of the first side surface 34A of the brush 34, the inner wall surface 50A of the first side wall portion 50 and the tip side upper portion 34G of the first side surface 34A of the brush 34 A gap 68 is formed between the and.

On the other hand, as shown in FIG. 8, when the armature 12 rotates in the second direction, the brush 34 is pressed toward the second side wall portion 52 by the tangential frictional force of the commutator 26 acting on the brush 34. The protrusion 76 comes into contact with the tip-side lower portion 34I of the second side surface 34B of the brush 34. Further, in the state where the protrusion 76 is in contact with the tip end side lower portion 34I of the second side surface 34B of the brush 34, the inner wall surface 52A of the second side wall portion 52 and the tip end side upper portion 34J of the second side surface 34B of the brush 34 A gap 78 is formed between the and. The gap 68 is an example of the "first gap" in the present invention, and the gap 78 is an example of the "second gap" in the present invention.

According to the second embodiment of the present invention, as shown in FIG. 7, when the armature 12 rotates in the first direction and the brush 34 is pressed toward the first side wall portion 50, a protrusion is formed. When the portion 66 comes into contact with the tip end side lower portion 34H of the first side surface 34A of the brush 34, the upper surface 34C of the brush 34 is supported by the upper wall portion 54 of the brush holder 44, and the first side surface 34A of the brush 34 is supported. The lower portion 34H on the tip end side is supported by the inner wall surface 50A of the first side wall portion 50. Further, at this time, since a gap 68 is formed between the inner wall surface 50A of the first side wall portion 50 and the upper end side upper portion 34G of the first side surface 34A of the brush 34, the tip of the first side surface 34A of the brush 34 is formed. The lower side portion 34H is reliably supported by the inner wall surface 50A of the first side wall portion 50. As a result, even if the armature 12 rotates in the first direction, the lower end side of the brush 34 is supported by the inner wall surface 50A of the first side wall portion 50, so that the lower end side of the brush 34 vibrates in the tangential direction of the commutator 26. Can be suppressed.

Further, as shown in FIG. 8, when the armature 12 rotates in the second direction and the brush 34 is pressed toward the second side wall portion 52, the protrusion 76 is the second side surface 34B of the brush 34. In addition to the upper surface 34C of the brush 34 being supported by the upper wall portion 54 of the brush holder 44 by coming into contact with the lower end side lower portion 34I of the brush 34, the lower end side lower portion 34I of the second side surface 34B of the brush 34 is the second side wall portion. It is in a state of being supported by the inner wall surface 52A of 52. Further, at this time, since a gap 78 is formed between the inner wall surface 52A of the second side wall portion 52 and the upper end side upper portion 34J of the second side surface 34B of the brush 34, the tip of the second side surface 34B of the brush 34 is formed. The lower side portion 34I is reliably supported by the inner wall surface 52A of the second side wall portion 52. As a result, even if the armature 12 rotates in the second direction, the lower end side of the brush 34 is supported by the inner wall surface 52A of the second side wall portion 52, so that the lower end side of the brush 34 vibrates in the tangential direction of the commutator 26. Can be suppressed. From the above, when the armature 12 rotates in either the first direction or the second direction, it is possible to suppress the generation of abnormal noise due to the brush 34 colliding with the brush holder 44.

In the second embodiment of the present invention, the modification of the first embodiment may be applied.

[Third Embodiment]
Next, a third embodiment of the present invention will be described.

FIG. 9A is a top view showing a comparative example with respect to the third embodiment of the present invention. In this comparative example, the inner wall surfaces 50A and 52A of the first side wall portion 50 and the second side wall portion 52 are formed in a straight shape. The first side wall portion 50 and the second side wall portion 52 are symmetrically configured. When the armature 12 rotates in the first direction, the brush 34 has a first contact point 90 in which the lower end side 34H of the first side surface 34A contacts the protrusion 66, and the rear end of the first side surface 34A is the first side wall. It is supported by the first side wall portion 50 at the second contact point 92 in contact with the inner wall surface 50A of the portion 50. In this case, the central axis A1 of the brush 34 is inclined with respect to the central axis A2 of the brush holder 44 when viewed from above the brush holder 44.

In this comparative example, at the initial stage of use of the brush 34, the distance L between the first contact point 90 and the second contact point 92 along the central axis A2 of the brush holder 44 is L0. Further, the distance between the first contact point 90 and the second contact point 92 along the direction orthogonal to the central axis A2 of the brush holder 44 in the top view of the brush holder 44 is the inner wall surface 50A of the first side wall portion 50. Since it corresponds to the protrusion height of the protrusion 66 with respect to the distance H, it is constant. Then, at the initial stage of using the brush 34, the inclination angle θ0 of the central axis A1 of the brush 34 with respect to the central axis A2 of the brush holder 44 is calculated by the following equation (1) when viewed from above the brush holder 44.
θ0 = arctan (H / L0) ... (1)

On the other hand, at the end of the life of the brush 34, the distance L between the first contact point 90 and the second contact point 92 along the central axis A2 of the brush holder 44 is L1 (L0> L1). Then, at the end of the life of the brush 34, the inclination angle θ1 of the central axis A1 of the brush 34 with respect to the central axis A2 of the brush holder 44 when viewed from above the brush holder 44 is calculated by the following equation (2).
θ1 = arctan (H / L1) ... (2)

However, when the inner wall surfaces 50A and 52A of the first side wall portion 50 and the second side wall portion 52 are straightened as in this comparative example, the central axis A2 of the brush holder 44 is caused by the wear of the brush 34. As the distance L between the first contact point 90 and the second contact point 92 along the above becomes shorter, the inclination angle increases from θ0 to θ1 (θ0 <θ1). That is, as the wear of the brush 34 progresses, the contact angle of the brush 34 with respect to the commutator 26 changes.

On the other hand, in the third embodiment of the present invention, it is configured as follows. FIG. 9B is a top view showing a third embodiment of the present invention. In the third embodiment of the present invention, the inner wall surfaces 50A and 52A of the first side wall portion 50 and the second side wall portion 52 are the inner wall surface 50A toward the rear end side of the first side wall portion 50 and the second side wall portion 52. It is formed in a tapered shape so that the interval of 52A is widened. The first side wall portion 50 and the second side wall portion 52 are symmetrically configured.

Further, in the third embodiment of the present invention, the first side wall portion 50 and the second side wall portion 52 are provided so that the inclination angle θ is the same at the initial stage of use of the brush 34 and the stage of the end of the life of the brush 34. The inner wall surfaces 50A and 52A are inclined with respect to the central axis A2 of the brush holder 44 when viewed from above the brush holder 44.

That is, in the third embodiment of the present invention, the distance L = L0 and the distance H = H0 at the initial stage of using the brush 34, and the distance L = L1 and the distance H = H1 at the end of the life of the brush 34. The first side wall portion 50 and the second side wall portion 52 are provided so that the inclination angle θ represented by the equation (3) is kept constant even if the tip of the brush 34 is worn due to the sliding contact with the commutator 26. The inner wall surfaces 50A and 52A are inclined with respect to the central axis A2 of the brush holder 44 when viewed from above the brush holder 44.
θ = arctan (H / L) ... (3)

Here, FIG. 10 is a graph illustrating the effect of the third embodiment of the present invention. In FIG. 10, the vertical axis shows the inclination angle of the brush 34, and the horizontal axis shows the amount of wear of the brush 34. Further, the graph G1 shows a case where the inner wall surfaces 50A and 52A of the first side wall portion 50 and the second side wall portion 52 are straight as shown in FIG. 9A, and the graph G2 is shown in FIG. 9B. As described above, the case where the inner wall surfaces 50A and 52A of the first side wall portion 50 and the second side wall portion 52 are tapered is shown.

As shown in FIG. 10, when the inner wall surfaces 50A and 52A of the first side wall portion 50 and the second side wall portion 52 are straight, the inclination angle increases with the wear of the brush 34, but the first side wall portion. When the inner wall surfaces 50A and 52A of the portion 50 and the second side wall portion 52 are tapered as described above, the inclination angle of the brush 34 is maintained substantially constant even if the tip of the brush 34 is worn.

As described above, according to the third embodiment, even if the tip of the brush 34 is worn due to the sliding contact with the commutator 26, the inclination angle of the brush 34 with respect to the central axis A2 of the brush holder 44 is maintained. As a result, the contact angle of the brush 34 with respect to the commutator 26 can be maintained even if the brush 34 wears.

In the third embodiment of the present invention, the protrusions 66 and 76 are formed on the first side wall portion 50 and the second side wall portion 52, respectively, but when the armature 12 rotates only in the first direction, The protrusion 66 may be formed only on the first side wall portion 50 corresponding to the first direction.

Further, when the armature 12 rotates only in the first direction, only the first side wall portion 50 corresponding to the first direction may be inclined so as to satisfy the above formula (3).

Further, in the third embodiment, the modification of the first embodiment may be applied.

Although the first to third embodiments of the present invention have been described above, the present invention is not limited to the above, and can be variously modified and implemented without departing from the gist thereof. Of course there is.

10 ... rotary machine, 12 ... armature, 14 ... yoke, 16 ... magnet, 18 ... end housing, 20 ... brush device, 22 ... shaft, 24 ... core, 26 ... commutator, 28 ... winding, 30, 32 ... Bearing, 34 ... Brush, 34A ... First side surface, 34B ... Second side surface, 34C ... Top surface, 34D ... Bottom surface, 34E ... Rear end surface, 34F ... Inclined surface, 34G ... Tip side upper part, 34H ... Tip side lower part, 34I ... Lower tip side, 34J ... Upper tip side, 36 ... Pressing member, 38 ... Holding member, 40 ... Front housing, 42 ... Housing body, 44 ... Brush holder, 46 ... Bearing accommodating part, 48 ... Inclined part, 50 ... First Side wall, 50A ... inner wall surface, 52 ... second side wall, 52A ... inner wall surface, 54 ... upper wall, 56 ... lid, 58 ... gap, 60 ... contact, 66 ... protrusion ("projection" and Example of "first protrusion"), 68 ... gap (example of "gap" and "first gap"), 76 ... protrusion (example of "second protrusion"), 78 ... gap ("second gap") Example), 90 ... 1st contact point, 92 ... 2nd contact point, A1 ... brush center axis, A2 ... brush holder center axis

Claims (4)

An armature with a commutator and
A brush whose tip slides into the commutator,
A brush holder having a pair of side wall portions and an upper wall portion and accommodating the brush,
A pressing member that presses the rear end surface of the brush toward the commutator side and the upper wall portion side.
Of the pair of side wall portions, a protrusion portion formed so as to project from the lower portion of the inner wall surface of the first side wall portion located on the downstream side in the rotation direction of the armature and in contact with the lower portion of the first side surface of the brush.
A gap formed between the inner wall surface of the first side wall portion and the upper portion of the first side surface of the brush on the upper side of the protrusion.
Rotating electric machine equipped with. The protrusion comes into contact with the lower end of the first side surface of the brush.
The gap is formed between the inner wall surface of the first side wall portion and the upper end side of the first side surface of the brush.
The rotary electric machine according to claim 1. The pressing member presses the rear end surface of the brush toward the first side wall portion.
The brush has a first contact point where the lower end side of the first side surface contacts the protrusion, and a second contact point where the rear end of the first side surface contacts the inner wall surface of the first side wall portion. Supported by the first side wall,
The central axis of the brush is inclined with respect to the central axis of the brush holder in the top view of the brush holder.
The distance between the first contact point and the second contact point along the central axis of the brush holder is L, and the second along the direction orthogonal to the central axis of the brush holder in the top view of the brush holder. When the distance between one contact point and the second contact point is H, the arctan (H / L) is kept constant even if the tip of the brush is worn due to the sliding contact with the rectifier. The inner wall surface of the first side wall portion is inclined with respect to the central axis of the brush holder in the top view of the brush holder.
The rotary electric machine according to claim 2. An armature that has a commutator and rotates in both directions,
A brush whose tip slides into the commutator,
A brush holder having a pair of side wall portions and an upper wall portion and accommodating the brush,
A pressing member that presses the rear end surface of the brush toward the commutator side and the upper wall portion side.
When the armature is formed so as to project from the lower part of the inner wall surface of the first side wall portion of the pair of side wall portions, the armature rotates in the first direction, and the brush is pressed toward the first side wall portion. , The first protrusion that contacts the lower part of the first side surface of the brush,
In a state where the first protrusion is in contact with the lower part of the first side surface of the brush, between the inner wall surface of the first side wall portion and the upper part of the first side surface of the brush on the upper side of the first protrusion. With the first gap formed in
When the armature is formed so as to project from the lower part of the inner wall surface of the second side wall portion of the pair of side wall portions, the armature rotates in the second direction, and the brush is pressed toward the second side wall portion. , A second protrusion that contacts the lower part of the second side surface of the brush,
In a state where the second protrusion is in contact with the lower part of the second side surface of the brush, between the inner wall surface of the second side wall portion and the upper part of the second side surface of the brush on the upper side of the second protrusion. With the second gap formed in
Rotating electric machine equipped with.

Images