JP5269797B2 - DC motor - Google Patents

Description

  The present invention relates to a direct current motor including a rotor and a stator, and having a brush for switching the polarity of the rotor.

  In this type of DC motor, it is known that the life of the brush strongly depends on the load of the electric motor. Long brush life is achieved only in the low power region. The brush wear increases on the high load side and the low load side of the DC motor. For example, the negative brush increases on the high load side and the positive brush wears on the low load side.

  The structure of the brush attached to an electric motor is known from Patent Document 1. There, the brush is tilted by 18 ° with respect to the outline of the slip ring in a drawing that can be understood so that the brush and the slip ring work together as needed. In a DC motor with a commutator, such a configuration is not important with respect to desirably extending the life of the brush. This is because, based on the increase in the occurrence of sparks, it leads to an instantaneous consumption of the carbon brush.

  From Patent Document 2, a configuration in which the brush is moved so that the center lines of the brush do not intersect is known. However, the circumferential interval (angle) between the contact points with the rotor on the central axis in the longitudinal direction of the brush is equal.

  From Patent Document 3, a configuration in which three brushes are provided is known. The circumferential angle (distance) between the two brushes is 60 ° or 120 °. The configuration to be compared is also shown in Patent Document 4.

German Publication No. 1763023A1 US Publication No. 4344072A1 British Publication No. 1537567A US Publication No. 5852352

  In view of the state of the art described above, the technical problem of the present invention is found to improve this type of DC motor with respect to brush life.

One possible solution to this task is given by the subject of claim 1. In a DC motor (1) comprising a rotor (3) and a stator (6), and having two brushes (7, 7) of a positive electrode and a negative electrode for polarity switching of the rotor (3),
The position of the two brushes (7, 7) is an initial position where the two brushes (7, 7) face each other on one reference axis (z) orthogonal to the longitudinal axis (x) of the rotor (3). Of the two brushes (7, 7) from each other and the position of each brush (7, 7) about the longitudinal axis (x) from a position after the translation . Set by rotational movement,
In integral translation of the two brushes (7,7), the intersection of the outer periphery of each of the longitudinal central axis of the two brushes (7,7) (y, y) and the rotor (3) ( The angles (α, β) between the diameter lines (D 1 , D 2 ) passing through S, S) and the reference axis (z) are 12.5 ° to 11 ° , respectively.
In the rotational movement of each of the brushes (7, 7) after the parallel movement, the positive brush (7) is rotationally moved (Δα) in a direction in which the angle (α) decreases, and the angle (α ′). with but a 7 ° to 11 °, the negative pole of the brush (7) is the angle (beta) rotational movement ([Delta] [beta]) has been the angle (beta ') so as to become 1 3 ° to 17 ° in a direction to increase In addition, it is proposed that the positions of the two brushes (7, 7) are set.
Surprisingly, a clear increase in lifetime has been found in the specified angular range in the sense that they wear equally even when used over a wide load variation range. An increase in the frequency of occurrence of sparks has not been confirmed. Preferably only two brushes are provided. The area where there is no brush between the brushes and the outer peripheral dimension is shorter is, for example, 82 to 98% of the outer peripheral dimension of the longer brushless area (when the angle is changed). The same applies to translation (see FIG. 2 below). In the case of the latter (translation), one brush is opposed to the other, and the other is moved in parallel at a distance of a to form an angle of 3 to 10 degrees so that it is advantageous for detection of the overall ratio. Here, in particular, one of the regions has a ratio of 82 to 93%.

  Further, preferably, the movement of the intersection of the positive electrode brush is made in the rotation direction of the rotor, and the movement of the intersection of the negative electrode carbon brush is made in the direction opposite to the rotation direction of the rotor.

  In the following, the subject matter of the other claims will be described in relation to the subject matter of claim 1, but also in their independent form.

It has been proposed that the longitudinal central axis of the brush intersects the longitudinal axis of the rotor. This is achieved by moving the intersection by rotating the brush around the longitudinal axis of the rotor, which further ensures that one brushless perimeter between the brushes is shorter than the oppositely exposed perimeter. Accompany. In two configurations of the brush, such a corresponding rotational movement of one or both brushes about the longitudinal axis of the rotor is achieved integrally or at different movement angles relative to the diametrically opposed configuration. Alternatively or in combination, the longitudinal central axis of the brush does not intersect the longitudinal axis of the rotor, and further penetrates the rotor, for example in a circular arc shape . This can be achieved, for example, by translation of one or two opposing brushes from a position corresponding to the diametrical direction. This also causes the intersection of the brush central axis with the outer circumference of the rotor to move on the contour of the rotor. This involves a shortening of the outer circumference without one brush and a corresponding extension of the opposite outer dimensions. In addition to this parallel movement state, the brush may be inclined with respect to each intersection. Here, the longitudinal central axis of the brush does not necessarily need to intersect the longitudinal axis of the rotor. It is further possible to easily adapt the brushes as a single unit by moving the opposing brushes in parallel so that the central axis in the longitudinal direction of the brushes divides and penetrates the rotor in an arc shape . This is because the corresponding holders are arranged to face each other from the front.

Apart from the circumferential or parallel movement of the brush or the holder containing the brush, preferably a shunt coil is introduced. Thereby, improved properties can be achieved, especially in the context of a moved holder or brush. Optimal intersecting angle with respect to specific rotor, about 12.5 °, and more takes place to be 11 to 11.5 °, etc., for example, 11.35 °. As a result of the proposed invention, the positive brush is in the direction of decreasing angle of 7-11 °, eg 8-10 °, more eg 7-8 °, preferably 7.5 °, 7.6 °, 7 .7 °, 7.8 °, or 7.9 °. Here, all intermediate values, particularly intermediate values of 1/10 ° step are included in the present disclosure. The negative brush is 10 to 17 ° in the direction of increasing the angle, more preferably 13 to 16 °, for example, 14.4 °, 14.5 °, 14.6 °, 14.7 °, 14.8 °. , 14.9 °, or 15 °. Here, all intermediate values, especially intermediate values in 1/10 ° steps, are also included. The total relative movement between both brushes falls within the range of 3-10 °. Here, too, all intermediate values, in particular intermediate values in 1/10 ° steps, are also included in the disclosure.

  The operation of the DC motor is performed through a smoothing capacitor circuit having an NTC (Negative Temperature Coefficient) thermistor for discharging after power-off, an electric resistance, and the like for load current limitation.

It is longitudinal direction sectional drawing of the direct-current motor as a part of electric fan. It is typical sectional drawing in the II-II line | wire in FIG. 1, and is related with the brush structure which concerns on a 1st Example. It is sectional drawing corresponding to FIG. 2, and is related with the brush structure which concerns on a 2nd Example. It is sectional drawing corresponding to FIG. 2, and is related with the brush structure which concerns on a 3rd Example.

  In the following, the present invention will be more apparent with reference to the accompanying drawings, in which only examples are illustrated. With reference to FIG. 1, first a DC motor 1 is shown and described. The electric motor 1 includes a rotor 3 having a rotor shaft 4, and a commutator 5 is provided at one end of the rotor shaft 4 so as not to rotate. Furthermore, a stator 6 that functions in conjunction with the rotor is provided.

  The polarity of the commutator 5 is switched via a brush 7 arranged so as to be substantially opposed. These 7 are held in the brush holder 8 and pressed against the commutator 5 from the back by a support spring 9.

In order to achieve a high brush life, even over different loads, preferably over the entire allowable load range of the DC motor 1, according to the invention described above, the brush 7 has a rotating shaft of the rotor as in the diametrically opposed configuration. They are not opposed via x, but rather are offset from this position. 2 and 3, the reference axis z perpendicular to the longitudinal axis x of the rotor is the axis that the brush 7 and the longitudinal central axis y of the brush will extend in the normal configuration facing the diametrical direction. Show. Reference sign D is a diameter line of the rotor 3.

Next, when both the brush 7 oblige counterclockwise twice, moving the intersection S of both brush 7 about the outer periphery of the rotor is achieved. Move is in the range of 3 to 10 °, for example in the present embodiment is about 5.1 °. In the latter case (5.1 °), in this example, the movement amount of the positive brush is 3.4 ° and the movement amount of the carbon brush of the negative electrode is 1.7 ° (the first rotation with respect to the common rotation direction). The numerical value is set to negative and the second numerical value is set to positive).

FIG. 2 shows an embodiment in which the opposing brushes 7 or their brush holders 8 are moved in parallel from their diametric positions so that their longitudinal central axis y is separated by a parallel distance a with respect to the axis z. Has been. Due to the parallel movement of the brush 7, the movement of each intersection S with the rotor or the outer periphery of the commutator 5 in the longitudinal center axis y of the brush is in the rotation direction r for the positive brush and the rotation direction for the negative brush. Achieved in the opposite direction of r. As a result, the outer peripheral dimension of the exposed portion between the brushes 7 also changes. This outer peripheral dimension is equal in a normal diametrical arrangement with the brush facing. By the intersection movement, a shortening of the outer peripheral dimension u ₁ is achieved in the extension of the outer peripheral dimension u ₂ of the other exposed part.

Due to the parallel movement of the brushes 7, their longitudinal axes y intersect with the rotor 3 or commutator 5 in a circular arc shape at a distance a from the rotor longitudinal axis x. Here, the distance a is selected so that the angle α or β formed between the axis z and the lines D and D intersecting the intersection S and the longitudinal axis y of the rotor 3 is 12.5 ° to 11 °. Has been. Further, as a result, the amount of movement of the intersection point S falls within, for example, 1 to 5% of the outer peripheral dimension of the commutator 5. Correspondingly, the outer peripheral dimension u1 of the exposed part becomes, for example, 0.6 to 0.95 times the outer peripheral dimension u2 of the opposite exposed part by the accompanying movement of both intersections S with respect to the contour line proposed here. To be achieved.

Alternatively, as shown in FIG. 3, the rotational movement of the brush 7 or the holder 8 around the longitudinal axis x is performed so that the longitudinal central axis y of the brush intersects the longitudinal axis x of the rotor, respectively. The movement may be realized. Also here, the brush 7 is arranged so as to move with movement, and as a result, the positive brush 7 moves in the rotation direction r and the negative brush 7 moves in the direction opposite to the rotation direction r. The angle α and β forms with the axis z occurring herein, and a numerically substantially match those in the above embodiments, will now correspondingly also be realized differently outer peripheral dimension u ₁ and u _2.

Furthermore, as shown in FIG. 4, starting from the embodiment after the translation of the brushes 7 shown in FIG. 2, these brushes 7 may be additionally tilted from the achieved intersection point S. . Thereby, the longitudinal central axis y of the brush does not necessarily need to intersect with the rotor axis x, but rather may intersect with the rotor 3 or the commutator 5 so as to be divided into arcs .

  The amount of movement from the first diametrically opposed position is such that, for example, the positive brush rotates around the longitudinal axis x of the rotor or translates relative to the axis z, and the subsequent angle α is the other brush. It may be varied, as is different from the angle β caused by the corresponding movement of 7.

  In these drawings, the above angle is exaggerated for better understanding.

  As a result of the proposed solution, it is guaranteed that there will be less rapid polarity switching for the positive brush and more rapid polarity switching for the negative brush to optimize polarity switching over a wide load area. Yes.

Hereinafter, typical values are the initial moving angle (α, β) of 12.5 or 11.35 °, the moving angle of the positive and negative carbon brushes (−Δα, + Δβ) , both carbon brushes Table 1 shows the total travel angles (α−Δα, β + Δβ) actually set for each of these and the measured values of the output exceeding 1000 hours (minimum or maximum).

  All the disclosed features (by themselves) form part of the invention. The disclosure content of the enclosed / attached priority document (a copy of the previous application) is still fully incorporated into the disclosure of this application, and the patent and Included within the scope of the claims.

1 DC motor 3 rotor 4 rotor shaft 5 commutator 6 stator 7 Brush 8 brush holder 9 support spring a parallel distance r direction of rotation u _{1, u 2} outer peripheral dimension x rotor axis of rotation (longitudinal axis)
y Brush longitudinal center axis z Reference axis D Diameter line S Intersection α, β Angle

Claims (2)

In a DC motor (1) comprising a rotor (3) and a stator (6), and having two brushes (7, 7) of a positive electrode and a negative electrode for polarity switching of the rotor (3),
The position of the two brushes (7, 7) is an initial position where the two brushes (7, 7) face each other on one reference axis (z) orthogonal to the longitudinal axis (x) of the rotor (3). Of the two brushes (7, 7) from each other and the position of each brush (7, 7) about the longitudinal axis (x) from a position after the translation . Set by rotational movement,
In integral translation of the two brushes (7,7), the intersection of the outer periphery of each of the longitudinal central axis of the two brushes (7,7) (y, y) and the rotor (3) ( The angles (α, β) formed by the diameter lines (D 1 , D 2 ) passing through S, S) and the reference axes (z) are 12.5 ° to 11 ° , respectively.
In the rotational movement of each of the brushes (7, 7) after the parallel movement, the positive brush (7) is rotationally moved (Δα) in a direction in which the angle (α) decreases, and the angle (α ′). with but a 7 ° to 11 °, the negative pole of the brush (7) is the angle (beta) rotational movement ([Delta] [beta]) has been the angle (beta ') so as to become 1 3 ° to 17 ° in a direction to increase Further, the direct current motor is characterized in that the positions of the two brushes (7, 7) are set. Central longitudinal axis of the brush (7) (y) is separated only the predetermined distance from the longitudinal axis of the rotor (x), characterized in that through the rotor (3), a DC motor according to claim 1 .

Images