JP2019068670A - Brush holder device and motor with brush mounted with the same - Google Patents

Abstract

To provide: a brush holder device that while manufactured at low cost without requiring any special process control during the manufacture, can be securely reduced in quantity of variation in contact phase angle in an abrasion stage of a brush to prevent various problems due thereto; and a motor with the brush which is mounted with the same.SOLUTION: A brush 22 is brought into slide contact with an outer peripheral surface of a commutator 10 with elasticity accompanying bending of a brush arm 21, and then while the brush arm 21 is made to vary in angle as the brush 22 wears off, the brush 22 is kept in the slide contact. The center Cb of an arcuate trajectory (P1-P2) where an axial base point of the brush 22 moves when the brush arm 21 varies in angle as the brush 22 wears off is aligned with the middle point P01 of a brush length in directions in which the brush 22 contacts and leaves the commutator 10 so as to reduce a variation width S2 of the axial base point in a tangential direction of the brush 22 to the commutator 10, thereby reducing the quantity of variation in contact phase angle of the brush 22.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a brush holder device for supporting a brush for supplying power to an armature (armature) and bringing the brush into sliding contact with the outer peripheral surface of a commutator (commutator), and a brushed motor equipped with the same.

  In this type of brushed motor, a field magnet constituting the stator is fixed to the inner peripheral surface of the housing, and an armature and a commutator constituting the rotor are provided on a rotary shaft rotatably supported in the housing. . A pair of brush bases of the brush holder device are fixed in the housing, the base end of the brush arm is fixed on the brush bases, and the brush is fixed on the tip side of each brush arm. The brush during operation of the motor is pressed by the elastic body such as a spring through the brush arm and is in sliding contact with the outer peripheral surface of the commutator, whereby the direction of the winding to be energized and the flowing current is continuous in the multiple windings of the armature. Reversely to continue the rotation of the rotor.

  In an arm-type brush holder device utilizing such a pressing force of an elastic body, the brush arm changes its angle as the brush wears, and the angle (hereinafter referred to as contact phase angle) of the brush to the commutator changes accordingly Do. When the contact phase angle changes, a shift occurs in the energization timing with the commutator, and sparks generated between the commutator increase, which shortens the brush life and also causes a reduction in motor efficiency and output. As a technique focusing on this point, one described in Patent Document 1 can be mentioned.

  The brush holder device of Patent Document 1 is a technique focusing on a point in which the brush moves along an arc-like locus when the angle of the brush arm changes as the brush wears. By forming the shape of the brush into an arc shape in accordance with the movement trajectory, it is considered that the same contact phase angle is always maintained regardless of the wear of the brush.

Japanese Utility Model Application Publication No. 62-057566

  However, achieving the desired effect by the technique of Patent Document 1 is limited due to the manufacturing limitations of the brush holder device. That is, as described above, in order to always maintain the same contact phase angle regardless of the wear of the brush, the brush must have an accurate arc shape that follows the movement trajectory, and the brush direction correctly attached. It is necessary to satisfy requirements such as being attached to the brush arm at an angle about the axis of

  In order to satisfy these requirements, the brush shape, the direction of assembly, and the mounting angle must be very strictly controlled in the molding and assembly steps of the brush, which causes an increase in manufacturing cost. If the mounting direction of the brush is different, there is a concern that the shift of the contact phase angle may be expanded. If the motor is small, the brush is small, and it is difficult to visually identify the mounting direction error or by an image. . In addition, even if the process control is strictly carried out, the contact phase angle may change due to a manufacturing error and the above requirement can not be satisfied due to a manufacturing error, and there is also a problem that the certainty is poor as a countermeasure.

  The present invention has been made to solve such problems, and the object of the present invention is to wear the brush while making it possible to carry it out at a low cost without requiring special process control during manufacturing. It is an object of the present invention to provide a brush holder device and a brushed motor equipped with the same capable of reliably reducing the amount of change in the contact phase angle in the process and preventing various problems resulting therefrom.

  In order to achieve the above object, in the brush holder device of the present invention, the base end of the brush arm is fixed on the brush base, and the brush is fixed on the tip side of the brush arm, concentric with the rotation axis of the rotor. The brush comes in sliding contact with the outer peripheral surface of the provided commutator due to the elasticity of the brush arm due to the bending, and the brush arm can be maintained in sliding contact while changing the angle of the brush arm with the wear of the brush. In the brush holder device, when the distance between the center of the commutator and the center of the length in the contact and separation direction of the brush is 100%, and the angle of the brush arm changes with abrasion of the brush The center of the locus of movement is set within ± 17% of the middle point of the brush length in the contact / separation direction of the brush with respect to the commutator. Characterized in that there (claim 1).

  According to the brush holder device configured as described above, the sliding contact of the brush with the commutator is maintained while changing the angle of the brush arm with the wear of the brush, and the axial base point of the contact surface of the brush at this time follows the locus I approach a committer. Since the center of the arc locus is set within ± 17% in the contact and separation direction with respect to the middle point of the brush length, the initial axial base point and the final axial base point of the brush are tangents to the brush tangent to the commutator Approach in the direction. For this reason, the fluctuation range of the tangential direction of the axial base point from the beginning to the end of the brush is reduced, and the variation amount of the contact phase angle of the brush correlated with the fluctuation range is also reduced. As a result, it is possible to suppress the deviation of the energization timing between the brush and the commutator, which occurs due to the change of the contact phase angle.

As another aspect, the central axis of the brush is 100% of the distance between the center of the arc locus along which the brush axial base moves and the tangential center of the brush along with the abrasion in the tangential direction of the brush with respect to the commutator. Preferably, the distance from the center of rotation of the commutator is within ± 2.3% (claim 2).
According to the brush holder device configured as described above, when the distance Y in the tangential direction of the central axis of the brush with respect to the rotation center of the commutator is changed, the contact angle of the brush changes as shown in FIG. In the case of the distance X = + 17% in the approaching and separating direction shown in (b) in the figure, the distance Y = 0 to 2.3% is determined as the distance Y satisfying the allowable range (84 to 95 °) of the contact angle. In the case of the distance X = −17% shown in (c) of the inside, the distance Y = 0 to −2.3% is obtained. As a result, if the distance Y is set within ± 2.3%, the contact angle of the brush can be kept within the allowable range.

As another aspect, it is desirable to mount a brush holder device according to claim 1 to constitute a brushed motor (claim 3).
According to the motor with a brush configured as described above, the brush holder device achieves the effects and advantages described in claim 1 or 2.

  According to the brush holder device of the present invention and the motor with a brush mounted thereon, the change of the contact phase angle in the process of wearing the brush can be realized at low cost without requiring special process control during manufacturing. The amount can be reliably reduced to prevent various problems resulting from this.

It is a sectional view showing a motor with a brush of an embodiment. It is the figure which looked at the brush holder apparatus in an end bell from the front side. It is a schematic diagram which shows the movement locus | trajectory of the brush accompanying abrasion of the brush holder apparatus of embodiment. It is explanatory drawing which compared the specification and test result of the brush holder apparatus of embodiment with the thing of a prior art. It is a schematic diagram corresponding to FIG. 3 which shows a brush holder apparatus when wear of a brush progresses. It is a figure which shows the analysis result by the simulation which calculated | required the contact angle of the brush when changing the distance Y to the tangent direction of the central axis of the brush with respect to the rotation center of a commutator. It is a schematic diagram which shows the movement locus | trajectory of the brush accompanying abrasion of the brush holder apparatus of a prior art.

Hereinafter, an embodiment of a brush holder device embodying the present invention, and a brushed motor equipped with the same will be described.
FIG. 1 is a cross-sectional view showing a brushed motor according to this embodiment. The left side in the drawing corresponds to the front side of the motor, and the right side corresponds to the rear side of the motor.

  The housing 2 of the motor 1 is composed of a metal case 3 and an end bell 4 made of synthetic resin. The metal case 3 has a bottomed cylindrical shape that opens toward the rear side, and the end bell 4 is fitted in the step portion of the open end of the metal case 3 so as to close the opening. The end bell 4 is fixed by caulking by cutting and bending the part.

  A field magnet 5 of two poles is fixed to the inner peripheral surface of the metal case 3 by a projection (not shown) provided on the inner peripheral surface of the metal case 3 and a spring (not shown). The stator 6 (stator) is configured by the metal case 3 that functions as A rotor 7 (rotor) is disposed inside the field magnet 5, and the rotor 7 is composed of a rotating shaft 8, an armature 9 (armature) and a commutator 10 (commutator). The field magnet 5 may be fixed to the metal case 3 by an adhesive, or a protrusion, a spring and an adhesive may be used in combination.

  The front side of the rotary shaft 8 of the rotor 7 is rotatably supported by the bearing 12 in the metal case 3, and the rear side of the rotary shaft 8 is rotatably supported by the bearing 13 in the end bell 4. This rotary shaft 8 is a metal It projects from the case 3 to the front side and functions as an output shaft of the motor 1.

  The armature 9 is formed by winding a three-pole winding 15 around a core 14 fixed on a rotating shaft 8, and a magnetic gap is formed between the outer peripheral surface of the core 14 and the inner peripheral surface of the field magnet 5. A predetermined clearance is formed. The commutator 10 is provided on the rotation shaft 8 so as to be located in the end bell 4 and has a conductor piece whose cylindrical shape is divided into three pieces in the circumferential direction so as to cover the outer peripheral surface. Although not shown, these conductor pieces are electrically connected to the respective poles of the winding 15.

The number of poles of the winding 15 and the number of conductor pieces of the commutator 10 are not necessarily three. The number of poles of the winding 15 is a natural number of 2 or more, and the commutator 10 can take 0.5 times the number of poles of the winding 15 or a natural number.
A cooling fan 16 is mounted between the armature 9 on the rotating shaft 8 and the commutator 10, and the cooling fan 16 rotates with the rotating shaft 8 to cool the armature 9 and the brush holder device 18 described below.

A brush holder device 18 is disposed in the end bell 4 so as to include the commutator 10. The configuration of the brush holder device 18 will be described below.
FIG. 2 is a front view of the brush holder device 18 in the end bell 4.
As shown in FIGS. 1 and 2, metal brush bases 19 are fixed at positions in the end bell 4 facing 180 ° centering on the commutator 10, and terminals 20 are integrally formed or connected to each brush base 19. It is done. Each terminal 20 protrudes from the inside of the end bell 4 toward the outside rear side, and can connect a power supply cable (not shown) connected to an external power supply.

  A fixed surface 21a (base end) of the brush arm 21 is fixed to one side of each brush base 19 by caulking or the like, and the brush arm 21 is electrically connected to the terminal 20 via the brush base 19. An R portion 21b having a predetermined curvature is formed in the brush arm 21 in the vicinity of the fixed surface 21a, and one obtuse angle at one end on the tip side of the brush arm 21 holding the brush 22 than the R portion 21b. A bent portion is formed on the tip to direct the tip to the commutator 10 side. The bent portion is provided to make the contact angle between the brush 22 and the commutator 10 appropriate, and may be linear or curved. When this bent portion is provided, it may have a right angle or an acute angle depending on the arrangement of the brush base 19 and the brush arm 21 in the end bell 4.

  A brush 22 made of carbon is fixed to the tip of each brush arm 21, and each brush 22 is positioned facing 180 ° across the commutator 10. As a result, the pair of brush arms 21 and brushes 22 are arranged in a staggered positional relationship that is point symmetric with respect to the commutator 10. The pair of brush arms 21 may be arranged in line symmetry with respect to a straight line passing through the center of the commutator 10 depending on design circumstances such as the arrangement of the terminals 20.

  Each brush arm 21 is made of an elastic plate material such as beryllium copper, and the edges 21c on the front side and the rear side are bent at a right angle except for the region on the base end side. As a result, the brush arm 21 is given elasticity in the proximal end region, and is given rigidity in the other regions, and the proximal end region is flexed to make each brush 22 a part of the commutator 10 by elasticity. It is in contact with the outer peripheral surface.

  When power is supplied from the feed cable to the terminal 20, a current is caused to flow through the winding 15 of the armature 9 through the brush arm 21, the brush 22 and the commutator 10 to generate a magnetic field in the core 14. The rotor 7 rotates by suction and repulsion. Each brush 22 is in sliding contact with the outer peripheral surface of the commutator 10 as the rotor 7 rotates, and the direction of the winding 15 to be energized and the flowing current is continuously switched among the plurality of windings 15 of the armature 9 The magnetic field of the core 14 changes continuously and the rotor 7 keeps rotating.

  By the way, in the arm type brush holder device, various problems such as an increase of sparks at the time of rectification occur due to the change of the contact phase angle with the wear of the brush. Is formed in an arc shape following the movement trajectory. However, as described in [Problems to be solved by the invention], it is necessary to strictly control the brush shape and the mounting angle to the brush arm, so that the manufacturing cost rises, and the desired effect can not be achieved. In some cases there is little certainty.

  FIG. 3 is a schematic view showing the movement locus of the brush 22 with the wear of the brush holder device 18 according to this embodiment, and in detail, the movement locus of the axis origin of the brush 22 (the root point on the central axis L of the brush 22) It shows. In the following description, the horizontal direction in the drawing is expressed as the contact / separation direction of the brush 22 with respect to the commutator 10, and the vertical direction in the drawing is expressed as the tangential direction of the brush 22 with respect to the commutator 10.

  When the brush 22 shown in the drawing is not worn out (hereinafter referred to as the initial position of the brush 22), the axis base point is located at P1 in the drawing, and the brush arm 21 changes its angle as the brush 22 wears. The axis origin follows an arc locus and approaches the commutator 10, whereby the sliding contact of the brush 22 with the commutator 10 is maintained.

  Then, when all the brushes 22 are worn (hereinafter referred to as the end of the brushes 22), the axis origin of the brushes 22 reaches the position P2 closest to the commutator 10. The movement distance of the axis base point from P1 to P2 is similar to the length of the brush 22 (the dimension in the direction of contact with the commutator 10) although there is a difference between the curve and the straight line. It can be considered.

  In the process of wearing the brush 22, due to the structure of the arm-type brush holder device 18, a change in the contact phase angle can not be avoided, and it has been known that the smaller the amount of change in the contact phase angle is desirable, The current situation is that the setting method has not been established.

  In view of the above-mentioned problems of Patent Document 1 and the present recognition of the contact phase angle, the inventor moves the contact phase angle change amount in the process of wearing the brush 22 and the axial base end of the brush 22 following the arc locus. Attention was focused on the correlation with the fluctuation range in the tangential direction with respect to the commutator 10 (indicated by S2 in FIG. 3 and S1 in FIG. 7).

  As described above, the axial base point of the brush 22 moves along the arc locus in the course of wear, and the positional displacement (variation) of the brush 22 in the tangential direction with respect to the commutator 10 accordingly. The variation width in the tangential direction of the axial base point of the brush 22 at this time (hereinafter sometimes referred to simply as the variation width in the tangential direction) correlates with the change amount of the contact phase angle of the brush 22, and the variation width in the tangential direction is The smaller the value, the smaller the amount of change in the contact phase angle. Therefore, it is possible to minimize the amount of change in the contact phase angle by reducing the tangential fluctuation of the brush 22 as much as possible during the wear process.

Based on the above findings, in the present embodiment, each requirement of the brush arm 21 is optimally set in order to reduce the fluctuation range in the tangential direction of the brush 22, and the details will be described below.
Among the requirements of the brush arm 21, an important requirement that affects the tangential variation of the brush 22 is the central position of the arc trace that the brush 22 follows during the wear process.

FIG. 7 is a schematic view showing a movement locus of the brush 22 caused by the wear of the conventional brush holder device 31 not paying attention to the variation width in the tangential direction of the brush 22. As shown in FIG.
In the initial state of the brush 22 shown in FIG. 7, the axial base point of the brush 22 is located at P1 coincident with the rotation center Cc of the commutator 10 in the tangential direction, and the axial base point of the brush 22 moves along with abrasion. The center Cb is shifted toward the commutator 10 by a distance X (1.373 mm as described later in this example) with respect to the midpoint P01 of the length of the brush 22 in the contact / separation direction.

  As the brush 22 wears, the axis origin follows an arc locus and approaches the commutator 10, and at the end of the brush 22, the axis origin reaches P2 closest to the commutator 10.

Since the center Cb of the arc locus is shifted to the side of the commutator 10 with respect to the midpoint P01 of the length of the brush 22, P2 of the final stage with respect to the initial P1 of the brush 22 is tangential to the commutator 10 Position is displaced to the tip side. As a result, in the process of moving from P1 to P2, the axial origin varies tangentially by S1.
Note that the variation width S1 in the tangential direction hardly changes even if the axial base point P1 of the brush 22 in the initial state coincides with or does not coincide with the rotation center Cc of the commutator 10 in the tangential direction.

  The contact phase angle of the brush 22 (the angle of the brush 22 with respect to the commutator 10) at this time is a value correlated with the fluctuation range S1 in the tangential direction of the axial base end of the brush 22. In order for the axial base end of the brush 22 to move in a tangential direction when it moves along an arc locus, the brush 22 needs to make a large angle change at that time, and as a result, the amount of change in the contact phase angle becomes large. As a result, a correlation is established between the two.

On the other hand, in the brush holder device 18 of the present embodiment shown in FIG. 3, the center Cb of the circular arc trajectory coincides with the midpoint P01 of the length of the brush 22 in the contact and separation direction without 0 mm) is different.
The center Cb of the arc locus in the present embodiment coincides with the center of the R portion 21 b of the brush arm 21 having the curvature radius R. Therefore, the center Cb of the arc trajectory can be specified from the curved shape of the R portion 21b.

  Then, as the brush 22 wears, the axis origin follows the arc locus and approaches the commutator 10, and reaches P2 at the end of the brush 22. Since the center Cb of the circular arc trajectory coincides with the midpoint P01 of the length of the brush 22 in the contact / separation direction, P2 of the final stage coincides with the initial P1 of the brush 22 in the tangential direction. In the process of moving from P.sub.2 to P.sub.2, the axis origin varies tangentially by S.sub.2.

  In this embodiment, P2 coincides with P1 in the tangential direction, as compared to the prior art in which P2 is displaced relative to P1 toward the tip side of the brush arm 21. For this reason, the fluctuation width S2 in the tangential direction of the axial base point of this embodiment is reduced compared to the fluctuation width S1 of the prior art by the amount that P2 is not displaced, and as a result, the change amount of the contact phase angle of the brush 22 is also conventionally Reduced compared to technology. From the geometrical point of view, the variation width S2 of this embodiment is the minimum value in the same arc locus (the radius from the center Cb and the brush length are the same), so the change amount of the contact phase angle is also minimized. It can be stopped.

  Therefore, according to the brush holder device 18 of the present embodiment, it is possible to reliably reduce the amount of change in the contact phase angle in the process of wearing the brush 22, and to thereby suppress the deviation of the energization timing with the commutator 10. Therefore, it is possible to prevent various problems caused by the deviation of the energization timing, for example, shortening of the brush life due to sparks generated with the commutator 10, or reduction of the motor efficiency and output.

  Then, in order to obtain the above-described effects, the center Cb of the arc locus along which the axial base point of the brush 22 moves with wear is made to coincide with the midpoint P01 of the length of the brush 22 in the contact and separation direction. The other requirements of the brush arm 21 (for example, the length of the brush arm 21, the length of the bending area, the plate thickness, the plate width, etc.) are completely the same as those of the prior art brush holder device 31 of FIG.

  Therefore, the brush 22 is molded in a usual shape in the molding process of the brush 22 and the brush 22 is fixed to the brush arm 21 as usual in the assembling process (for example, the base end of the brush 22 in the holding hole of the brush arm 21) As in the technique of Patent Document 1, there is no need to strictly control the brush shape and the mounting angle. For this reason, it is possible to prevent in advance the rise of the manufacturing cost due to the strict control in each process, and it can be implemented at a very low cost.

  In addition, when the brush holder device 18 is manufactured, if the center Cb of the arc locus of the axial base point and the midpoint P01 of the length of the brush 22 are maintained in a regular positional relationship, the above-mentioned effects can be achieved without fail. Very high certainty can be realized.

As described above, although the center Cb of the arc locus of the axial base point and the middle point P01 of the length of the brush 22 are set to a normal positional relationship, a certain degree of manufacturing error can not be practically avoided. . Therefore, in the present embodiment, the allowable range of the error is set.
Specifically, a desirable product life (working time) can be obtained if the center Cb of the arc locus is located within a range of ± 1.0 mm in the contact / separation direction with reference to the midpoint P01 of the brush length. Within this allowable range, the change amount of the contact phase angle hardly increases as compared with the case where the middle point P01 of the brush length and the center Cb of the arc locus coincide (error = 0 mm). Based on findings.

FIG. 4 is an explanatory view comparing the specifications and the test results of the brush holder device 18 of the present embodiment with those of the prior art shown in FIG.
The embodiment and the prior art are different only in the distance X of the center Cb of the arc locus to the midpoint P01 of the brush length, and the other specifications are the same. For example, the outer diameters of the commutators are both set to φ 8.6 mm, and the requirements of the brush arm 21 are also set the same. And the specification of the motor 1 in which the brush holder apparatus 18 and 31 were integrated is also the same, for example, the outer diameter is set to (phi) 35.8 mm.

  In the prior art, the distance X of the center Cb of the arc locus with respect to the midpoint P01 of the brush length is 1.373 mm (+ means a shift to the side of the commutator 10), which deviates from the tolerance of ± 1.0 mm. . On the other hand, in the embodiment, although the center Cb of the arc locus does not coincide with the middle point P01 of the brush length due to a manufacturing error, the distance X is 0.873 mm and thus satisfies the condition of the tolerance of ± 1.0 mm. ing.

The inventor conducted a life test of the brush holder devices 18 and 31 of the embodiment and the prior art, and measured the working time from the initial stage to the final stage multiple times for each. As shown in FIG. 4, in the embodiment, the working time is greatly extended in the embodiment as compared with the prior art, and it can be considered as a proof that the setting of the tolerance for the distance X is appropriate.
Therefore, in the present embodiment, the center Cb of the arc locus is made to coincide with the midpoint P01 of the length of the brush 22 in the contact / separation direction, but it is not necessary to make it coincide. As apparent from the results of the life test, if the distance X in the contact / separation direction of the center Cb of the arc locus with respect to the middle point P01 is set within ± 1.0 mm, the initial axial base point and the final axial base point of the brush 22 However, the amount of change in the contact phase angle can be sufficiently reduced because the width of the fluctuation in the tangential direction decreases as the tangential direction of the brush 22 approaches. The present invention includes such positioning of the center Cb.

  In the present embodiment, since the center of the R portion 21b of the brush arm 21 coincides with the center Cb of the arc trajectory at the base end of the axis, the center Cb can be identified from the curved shape of the R portion 21b. There are brush arms in which both do not match. And, as is clear from the above description, the center point of the brush length P01 should be coincident with the center Cb of the arc locus which can only specify the position virtually.

However, the R portion 21b located at the base end of the deflection of the brush arm 21 is located in close proximity to the center Cb of the arc locus in any of the various brush arms 21 having different shapes. For this reason, the center of the R portion 21b may be regarded as the center Cb of the arc locus, and may be made coincident with the middle point P01 of the brush length in the contact / separation direction.
As a result, since the center Cb of the arc locus is also very close to the middle point P01 of the brush length, the variation width of the tangential direction of the base end of the axis can be sufficiently reduced even in this case. The effect is comparable to the form. The present invention also includes the case where the center of the R portion 21b is made to coincide with the midpoint P01 of the brush length.

  The outer diameter of the commutator 10 of this embodiment is 7.55 mm, and the length of the brush 22 in the contact / separation direction is 4.3 mm. The optimum dimension of the distance X in the contact / separation direction of the center Cb of the arc locus with respect to the middle point P01 changes with the size of the motor. Since the contact direction position of the brush 22 depends on the diameter of the commutator 10 and the contact direction dimension of the brush 22, the optimum dimension of the distance X in the contact direction of the center Cb of the arc locus with respect to the midpoint P01 is the comitator It may be taken as a ratio to the distance between the center Cc of 10 and the center of the brush (dimension A in FIG. 3). In this embodiment, since the distance between the center Cc of the commutator 10 and the brush center is 7.55 / 2 + 4.3 / 2 = 5.925 mm, the tolerance range ± 1.0 mm is ± 17% of the distance between the center Cc of the commutator 10 and the brush center It becomes.

On the other hand, in the above description, the positional relationship between the central axis L of the brush 22 at the initial and final stages and the rotation center Cc of the commutator 10 is not mentioned, but it is the same as the distance X in the contact / separation direction. There is an acceptable range.
For example, the center Cb of the arc locus with respect to the midpoint P01 of the length of the brush 22 in the contact and separation direction in the initial state of the brush 22 shown in FIG. Are made coincident (distance X = 0 mm), and the central axis L of the brush 22 is made coincident (distance Y = 0 mm) with respect to the rotation center Cc of the commutator 10 in the tangential direction.

  As the wear of the brush 22 gradually progresses, the contact angle of the brush 22 with the outer peripheral surface of the commutator 10 (meaning the rotation angle of the commutator 10 from the reference angle 0 ° as shown in FIG. 5) The P2 position on the central axis L changes to the advance side. Although the change of the contact angle of the brush 22 varies depending on the settings of the distances X and Y, it is necessary to keep the contact angle of the brush 22 near 90 ° of the target value over the entire period from the initial to the end of the brush 22 There is.

Therefore, the distances X and Y were changed, and changes in the contact angle of the brush 22 with the commutator 10 from the initial stage to the final stage were analyzed by simulation.
As described above, since the allowable range of the distance X is ± 1.0 mm (+ on the commutator side, − on the anti-commitator side), under the three conditions of the distance X = 0 mm, +1.0 mm and −1.0 mm, The simulation which changed the distance Y was implemented, respectively. When the target value is 90 °, 84 to 95 ° is defined as an acceptable contact angle of the brush 22, and the contact angle does not deviate from the allowable range from the initial stage to the final stage of the brush 22 (tip side of the brush arm 21 + And proximal end-) were determined.

  As shown in the analysis result of FIG. 6, the contact angle of the brush 22 changes to the advance side according to the angle of the brush arm 21 which changes with the progress of the wear of the brush 22 as a tendency common to setting of each distance X. The distance X = + 1.0 mm shown in (b) in the figure, compared to the distance X = 0 mm which is the optimum value in the contact / separation direction shown in (a) in the figure later changing to the retard side. At -1.0 mm shown in (c), the change in the contact angle is large. When the distance X = + 1.0 mm, Y = 0 to +0.3 mm is determined as the distance Y satisfying the allowable range (84 to 95 °) of the contact angle, and when the distance X = -1.0 mm, the allowable range of the contact angle Y = 0 to -0.3 mm is obtained as the distance Y satisfying the above.

  Therefore, in addition to the condition regarding the distance X described in the embodiment, if the distance Y in the tangential direction of the central axis L of the brush 22 to the rotation center Cc of the commutator 10 is set within ± 0.3 mm, from the beginning of the brush 22 The contact angle of the brush 22 is kept within the allowable range over the entire period until the end. Therefore, the shift of the energization timing with the commutator 10 can be suppressed, and although not described in duplicate, various problems caused by the shift of the energization timing can be more reliably prevented.

  The tangential length of the brush 22 according to the present embodiment is 3.7 mm, and the distance between the center Cb of the arc locus along which the axial base point of the brush 22 moves with wear and the tangential center of the brush 22 is 13.28 mm. . The optimum dimension of the distance in the tangential direction of the central axis L of the brush 22 with respect to the rotation center Cc of the commutator 10 changes with the size of the motor. The tangential position of the brush 22 depends on the distance from the center Cb of the arc locus along which the axial base point of the brush 22 moves with wear to the tangential center of the brush 22, the brush 22 relative to the rotation center Cc of the commutator 10. The optimal dimension range of the distance of the central axis L of the center line L in the tangential direction is the distance from the center Cb of the arc locus along which the axis base point of the brush 22 moves with wear to the tangential center of the brush 22 (dimension B in FIG. 3) You can think of it as a ratio to Therefore, ± 1.0 mm is ± 17%. The allowable range ± 0.3 mm of the distance Y in the tangential direction of the central axis L of the brush 22 with respect to the rotation center Cc of the commutator 10 is tangent to the brush trajectory 22 and the center Cb of the arc locus along which the brush axial axis moves. It is ± 2.3% of the distance to the direction center.

  Although the description of the embodiment is finished above, the aspect of the present invention is not limited to this embodiment. For example, in the above embodiment and another example, the present invention is embodied in a brushed motor 1 in which the stator 6 has two poles and the armature 9 has three poles, and the brush holder device 18 mounted on the motor 1. However, if it is a brushed motor, the specification is not limited to the above embodiment, and the number of poles and the like can be arbitrarily changed.

  The specifications of the brush holder devices 18 and 31 according to the above-described embodiment and another example can be arbitrarily changed. For example, the shape and requirements of the brush arm 21 or the material of the brush 22 may be changed.

DESCRIPTION OF SYMBOLS 7 Rotor 8 Rotor axis 10 COMMITATOR 18 Brush holder apparatus 19 Brush base 21 Brush arm 21a Fixing surface (proximal end)
22 Brush L Central axis P1, P2 Axis origin P01, P02 Midpoint

Claims (3)

The base end of the brush arm is fixed on the brush base, and the brush is fixed on the tip end side of the brush arm, and the outer surface of the commutator concentric with the rotation axis of the rotor is elastic with the deflection of the brush arm. A brush holder device capable of maintaining the sliding contact of the brush while slidingly contacting the brush by changing the angle of the brush arm with the wear of the brush;
When the distance from the center of the commutator to the center of the contact direction of the brush is 100%, when the brush arm changes its angle as the brush wears, the center of the locus along which the axis origin of the brush moves The brush holder device according to claim 1, wherein the distance between the center point of the brush and the center point of the brush in the contact / separation direction of the brush with respect to the commutator is within ± 17%. When the distance between the center of the arc locus along which the axial origin of the brush moves and the tangential center of the brush with the abrasion is 100%, the central axis of the brush is in the tangential direction of the brush with respect to the commutator. The brush holder device according to claim 1, wherein the distance is within ± 2.3% from the center of rotation of the commutator.   A brushed motor equipped with the brush holder device according to claim 1.

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