JP2012175760A - Brush device and motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize performance of a motor while suppressing a spark discharge by actualizing excellent rectification without reference to the degree of wear of a brush body.SOLUTION: The brush device includes a brush body which is energized to abut against a rectifier which rotates in one direction on an abutting surface at a thickness-directional front end, and the brush body is constituted by stacking a plurality of brush body pieces, differing in resistance value from one another, in layers, and the abutting surface wears to move back along the thickness direction. The brush body is so constituted that an area where a brush body piece having a larger resistance value appears on the abutting area downstream side from a brush body piece having a lower resistance value when viewed from the rotating direction of the rectifier and the brush body piece having the lower resistance value appears on the abutting surface as the abutting surface moves back increases and an area where the brush body piece having the higher resistance value appears decreases.

Description

  The present invention relates to a brush device and a motor, and more particularly, to a brush device including a brush body that is urged along a thickness direction and abuts against a commutator, and a motor having the brush device.

Generally, in a DC motor or the like, rectification to a commutator is performed using a brush device. The brush device is provided with a brush body that is urged along the thickness direction to come into contact with the commutator, and rectification is performed by the brush body coming into contact with the commutator.
By the way, in the conventional DC motor, the current change at the time of rectification is very delayed due to the inductance of the armature coil, and the rectification may be insufficient. In this case, as a result of a large current change at the end of rectification, a large reactance voltage is generated, and a spark discharge is generated between the brush body and the commutator. This spark discharge roughens the commutator surface, forms an uneven surface, increases the amount of wear on the brush body, significantly reduces the life of the equipment, increases the vibration noise of the brush body, and affects the quality of the motor. It is a problem.

  As a method for suppressing spark discharge, resistance rectification for increasing the resistance of the brush body is generally used. However, if a high-resistance brush body is used, the efficiency of the motor decreases. As a countermeasure, the brush body is configured by layering the high resistance and low resistance parts in the direction of rotation of the commutator, and the high resistance part of the brush body is rectified in the later stage of rectification when insufficient rectification occurs. A brush device that is brought into contact with a child has been developed (for example, see Patent Document 1). With this brush device, it is possible to suppress spark discharge due to insufficient rectification while suppressing reduction in motor efficiency.

  However, when the brush body gradually wears as the motor usage time elapses, the urging force acting on the brush body toward the commutator decreases according to the amount of wear. As a result, the contact resistance between the brush body and the commutator increases, and the efficiency of the motor gradually decreases. Such a problem also occurs in the brush device described in Patent Document 1.

  On the other hand, in consideration of an increase in contact resistance due to wear of the brush body, a brush apparatus has been developed that employs a brush body configured by stacking a plurality of layers having different resistance values in the thickness direction (for example, Patent Document 2). reference). With this brush device, it is possible to suppress a reduction in the efficiency of the motor even if the contact resistance increases as a result of the low resistance layer abutting against the commutator when the brush body is worn.

  However, in the brush device described in Patent Document 2, since the distribution of the resistance value is uniform in the rotation direction of the commutator, there is a possibility that the rectification is insufficient. In addition, since the resistance value changes abruptly near the boundary between each layer, the magnitude of the current flowing through the commutator changes abruptly at the timing when the layer in contact with the commutator switches, and as a result, the performance of the motor is reduced. There is a risk of sudden changes.

JP 2001-351758 A JP 2008-99438 A

  Therefore, an object of the present invention is to provide a brush device capable of stabilizing motor performance while realizing good rectification and suppressing spark discharge regardless of the degree of wear of the brush body, and the brush device It is providing the motor provided with.

  According to the brush device of the present invention, the brush device according to the present invention has a contact surface that contacts the commutator rotating in one direction at the front end in the thickness direction, and is biased so as to contact the commutator at the corresponding contact surface. A brush device including a brush body, wherein the brush body is configured by laminating a plurality of brush body pieces having different resistance values, and the contact surface is along the thickness direction. The brush body is configured to wear backward, and the brush body is configured such that the brush body piece having a higher resistance value is in a rotating direction of the commutator than the brush body piece having a lower resistance value. As the abutment surface recedes as viewed from the side and the abutment surface recedes, the region where the brush body piece having the lower resistance value appears on the abutment surface increases, and the resistance value increases. The high brush body piece appears Is solved by has a configuration that region is reduced.

In the brush device described above, the high resistance brush body piece is positioned downstream of the low resistance brush body piece when viewed from the rotation direction of the commutator, thereby avoiding insufficient rectification in the later stage of commutation and generating sparks. Can be suppressed. Further, when the contact surface is retracted, the region where the low-resistance brush body piece appears on the contact surface increases, and the region where the high-resistance brush body piece appears decreases. It is possible to suppress a decrease in motor efficiency. Furthermore, since the region where the low resistance brush body piece appears on the contact surface gradually increases according to the degree of retraction of the contact surface (in other words, the degree of wear of the brush body), the contact resistance value is gradually increased. It is possible to suppress a sudden change in the performance of the motor.
As a result, a brush device capable of stabilizing motor performance while realizing good rectification and suppressing spark discharge regardless of the degree of wear of the brush body is provided.

  In the brush device, the brush body includes a plurality of brush body pieces, a first brush body piece, a second brush body piece having a resistance value larger than that of the first brush body piece, and the first brush body piece. The third brush body piece having a resistance value larger than that of the two brush body pieces is layered, and in the initial period from the start of consumption of the brush body to the end of consumption, the rotation direction on the contact surface The second brush body piece appears on the upstream side when viewed from the side, the third brush body piece appears on the downstream side, and the second brush body piece is formed on the abutting surface as the abutting surface is retracted. The appearing area increases, the area where the third brush body piece appears is decreased, and in the later stage of the period, the first brush body piece is upstream of the contact surface in the rotation direction. Appear, below As the second brush body piece appears on the side and the abutting surface retreats, the area where the first brush body piece appears on the abutting surface increases, and the second brush body piece appears. It is preferable that the area that is present decreases.

Further, in the above brush device, the layer of the third brush body piece is formed in a corner portion of the brush body that is located on the downstream side when viewed from the rotation direction and on the front end side in the thickness direction, The layer of the second brush body piece is adjacent to the layer of the third brush body piece in the brush body, from the corner portion located upstream from the rotation direction and located on the front end side in the thickness direction, The first brush body piece layer is formed at an angle toward the downstream side and the central portion in the thickness direction, and the layer of the first brush body piece is the second brush on the rear end side in the thickness direction of the brush body. It is preferable that it is formed adjacent to the layer of the main body piece so that the length in the thickness direction becomes shorter from the upstream side toward the downstream side as seen from the rotational direction.
Such a configuration is relatively simple as a configuration for stabilizing the motor performance while realizing good rectification and suppressing spark discharge regardless of the degree of wear of the brush body. That is, if it is said structure, it will become possible to acquire the effect of this invention by a comparatively simple structure.

In the above brush device, a boundary surface between the layer of the third brush body piece and the layer of the second brush body piece, and the layer of the second brush body piece and the layer of the first brush body piece The boundary surface of the third brush body piece and the second brush are inclined such that the downstream end thereof is located on the rear side in the thickness direction with respect to the upstream end as viewed from the rotational direction. The downstream end of the boundary surface between the body piece layer and the upstream end of the boundary surface between the second brush body piece layer and the first brush body piece layer are at the same position in the thickness direction. It is preferable that it is located at.
With such a configuration, the effects of the present invention can be obtained with a simpler configuration.

  Further, the above-described problem has a commutator that rotates in one direction and a contact surface that contacts the commutator at the front end in the thickness direction, and is biased to contact the commutator at the corresponding contact surface. A brush device including a brush body, wherein the brush body is configured by laminating a plurality of brush body pieces having different resistance values from each other, and the contact surface has the thickness The brush body is configured to wear backward so that the brush body piece having a higher resistance value at the contact surface is more rectified than the brush body piece having a lower resistance value. The region where the brush body piece having a lower resistance value appears on the contact surface increases as the contact surface retreats as it appears downstream from the rotation direction of the child, The brush body with a higher resistance value A region that appears is solved by has a configuration to decrease.

  With the motor having the above-described configuration, it is possible to stabilize the motor performance while realizing good rectification and suppressing spark discharge regardless of the degree of wear of the brush body.

  According to the brush device of the present invention, the high-resistance brush body piece is positioned downstream of the low-resistance brush body piece as viewed from the rotation direction of the commutator, thereby avoiding insufficient rectification in the later stage of commutation and sparking. Can be suppressed. Further, when the contact surface is retracted, the region where the low-resistance brush body piece appears on the contact surface increases, and the region where the high-resistance brush body piece appears decreases. It is possible to suppress a decrease in motor efficiency. In addition, the area where the low resistance brush body piece appears on the contact surface gradually increases according to the degree of retraction of the contact surface, so that the contact resistance value gradually changes and the motor performance changes rapidly. Can be suppressed. From the above results, it is possible to stabilize the motor performance while realizing good rectification and suppressing spark discharge regardless of the degree of wear of the brush body.

It is sectional drawing which shows schematic structure of the motor which concerns on this embodiment. It is explanatory drawing of the brush apparatus which concerns on this embodiment. It is a figure when a brush main body is seen from the upper side of the height direction. 4A to 4D are views when the brush body is viewed from the front side in the thickness direction. It is a figure which shows the rectification | straightening curve about the brush apparatus which concerns on this embodiment. It is a figure which shows the change of the abrasion loss of a brush main body, and a contact resistance value. 7A to 7D are diagrams illustrating an example of a method for manufacturing a brush body according to the present embodiment. It is the block diagram of the brush main body 11 which distributed each brush main body piece 15 three-dimensionally (the 1). It is the block diagram of the brush main body 11 which distributed each brush main body piece 15 three-dimensionally (the 2). It is a block diagram of the brush main body 11 which distributed each brush main body piece 15 three-dimensionally (the 3). It is a block diagram of the brush main body 11 which distributed each brush main body piece 15 three-dimensionally (the 4).

<< About the brush device and the motor according to this embodiment >>
Hereinafter, one embodiment of the present invention (hereinafter referred to as this embodiment) will be described with reference to FIGS. 1, 2, 3, 4 (a) to 4 (d), 5, 6, and 7 (a). This will be described with reference to (d). FIG. 1 is a cross-sectional view showing a schematic configuration of a motor according to the present embodiment. FIG. 2 is an explanatory diagram of the brush device according to the present embodiment. FIG. 3 is a diagram (plan view) when the brush body is viewed from above in the height direction. 4A to 4D are views (front views) when the brush body is viewed from the front side in the thickness direction. In addition, the figure represents the situation where the thickness direction front end of a brush main body changes, and it changes in order of Fig.4 (a), (b), (c), (d). FIG. 5 is a diagram showing a rectification curve for the brush device (conventional product) according to the present embodiment, and the rectification curve for a normal brush device is also shown in the drawing as a comparison target. FIG. 6 is a diagram showing changes in the amount of wear and the contact resistance value of the brush body. In the figure, the change in contact resistance in a normal brush device (conventional product) is also shown as a comparison. FIGS. 7A to 7D are diagrams showing an example of a method for manufacturing a brush body according to the present embodiment, which are manufactured in the order of FIGS. 7A, 7B, 7C, and 7D. The process proceeds.

First, a schematic configuration of a motor according to the present embodiment (hereinafter simply referred to as motor M) will be described.
The motor M according to the present embodiment adopts a known configuration except for the brush device S. That is, as shown in FIG. 1, the motor M includes a brush device S configured as described later, a shaft 1 serving as an output shaft, an iron core 3 on which a coil 2 is formed, a commutator 4, and a field mechanism. The magnet 5 and a housing 6 that accommodates the magnet 5 are included as main components.

  The shaft 1 is rotatably supported by a housing 6 via a bearing 7 and rotates in one direction in this embodiment. An iron core 3 is fixed to the shaft 1, and a magnet 5 is arranged around the outer periphery of the iron core 3. A commutator 4 is also fixed to the shaft 1. The commutator 4 is a cylindrical member that rotates in one direction integrally with the shaft 1, and includes a plurality of commutator pieces 4 a that are arranged at regular intervals along the rotation direction. And the commutator 4 switches the direction of the electric current which flows through the coil 2 by the commutator piece 4a contact | abutting with the brush main body 11 of the brush apparatus S switching with rotation.

Next, the brush device S according to the present embodiment (hereinafter simply referred to as the brush device S) will be described.
The brush device S is configured to pass a current to the coil 2 through the commutator 4. As shown in FIGS. 1 and 2, the brush body 11, the storage box 12, the urging spring 13, and a power supply lead wire. As a main component. The brush body 11 is a rectangular parallelepiped member made of graphite containing copper, the thickness direction is along the radial direction of the commutator 4, and the height direction is along the axial direction of the shaft 1. Further, the front end surface (contact surface T) in the thickness direction of the brush body 11 forms an arcuate curved surface along the outer periphery of the commutator 4.

  The brush body 11 having the above shape is urged along the thickness direction by the urging spring 13 which is also housed in the storage box 12 with a part thereof being stored in the storage box 12. As a result, the brush body 11 abuts on the rotating commutator 4 at the abutment surface T located at the front end in the thickness direction. In other words, the commutator 4 slides on the same surface while being in contact with the front end surface (contact surface T) of the brush body 11 on the outer peripheral surface thereof. As a result, the brush body 11 is worn so that the contact surface T moves backward along the thickness direction. That is, the brush main body 11 is gradually worn away in the thickness direction as the use time of the motor M elapses from the unconsumed state, and is consumed until the brush main body 11 cannot function properly.

  In the present embodiment, the period from when the brush body 11 starts to be consumed until the end of consumption (that is, the life of the brush body 11) is determined when the contact surface T is in a predetermined position (from the time when the motor M starts to be used). For example, it is a period from the time when the pigtail 14 is retracted to a position slightly before the position where the pigtail 14 is connected.

  Furthermore, the brush body 11 according to the present embodiment is configured by laminating a plurality of brush body pieces 15 having different resistance values from each other in layers. Specifically, the low resistance piece 15a as the first brush body piece, the medium resistance piece 15b as the second brush body piece, and the high resistance piece 15c as the third brush body piece are layered to overlap the brush body. 11 is constituted. Here, the resistance value of each brush body piece 15 increases in the order of the low resistance piece 15a, the middle resistance piece 15b, and the high resistance piece 15c. The resistance value of the brush body piece 15 increases as the copper content with respect to graphite, which is a constituent component, is lower. For example, the copper content of the medium resistance piece 15b is lower than the copper content of the low resistance piece 15a. It has become.

Hereinafter, the configuration of the brush body 11 according to the present embodiment will be described in detail with reference to FIGS. 3 and 4.
As described above, in the brush body 11 according to this embodiment, each of the three brush body pieces 15 forms a layer.

  Specifically, as shown in FIG. 3, first, the layer of the high resistance piece 15 c is located in the brush body 11 on the downstream side when viewed from the rotation direction of the commutator 4 and on the front end side in the thickness direction. It is formed at the corner (downstream front end). Next, the layer of the medium resistance piece 15b is adjacent to the layer of the high resistance piece 15c on the rear side in the brush main body 11, and is located on the upstream side when viewed from the rotation direction of the commutator 4 and on the front end side in the thickness direction. From the corner (upstream front end portion) to be inclined toward the downstream portion (downstream center portion) located at the center portion in the thickness direction. Finally, the layer of the low resistance piece 15a is adjacent to the layer of the medium resistance piece 15b on the rear end side in the thickness direction in the brush body 11, and the length in the thickness direction increases from the upstream side to the downstream side when viewed from the rotation direction. Is formed to be short.

Further, the boundary surface B1 between the layer of the high resistance piece 15c and the layer of the medium resistance piece 15b, and the boundary surface B2 between the layer of the medium resistance piece 15b and the layer of the low resistance piece 15a are from the rotation direction of the commutator 4. The downstream end is inclined so that the downstream end is positioned on the rear side in the thickness direction of the brush body 11 with respect to the upstream end.
Furthermore, the downstream end (denoted by x1 in FIG. 3) of the boundary surface B1 between the layer of the high resistance piece 15c and the layer of the medium resistance piece 15b, the layer of the medium resistance piece 15b, and the layer of the low resistance piece 15a The upstream end of the boundary surface B2 (denoted by x2 in FIG. 3) is located at the same position in the thickness direction of the brush body 11.

  With the configuration described above, in the brush body 11 according to this embodiment, the brush body piece 15 having a higher resistance value on the contact surface T rotates the commutator 4 than the brush body piece 15 having a lower resistance value. It appears on the downstream side when viewed from the direction. In other words, the configuration of the brush body 11 is such that, on the contact surface T, the brush body piece 15 having a higher resistance value is more downstream than the brush body piece 15 having a lower resistance value as viewed from the rotational direction of the commutator 4. It has a structure that appears.

  More specifically, as shown in FIGS. 4 (a) and 4 (b), at the initial stage of the brush body 11 from the start of consumption until the end of consumption (hereinafter simply referred to as the initial stage) due to the above-described configuration. In the contact surface T, the middle resistance piece 15b appears on the upstream side when viewed from the rotation direction of the commutator 4, and the high resistance piece 15c appears on the downstream side. On the other hand, in the latter part of the period from the start of consumption of the brush body 11 to the end of consumption (hereinafter simply referred to as the latter part), as shown in FIGS. , The low resistance piece 15a appears on the upstream side, and the middle resistance piece 15b appears on the downstream side. Note that only the middle resistance piece 15b appears on the contact surface T at the moment of switching from the initial stage to the late stage.

  Here, the initial term means a period from the time when the brush body 11 starts to be consumed to the time when the contact surface T reaches a preset position (set position). The setting position can be arbitrarily set. For example, the brush main body appearing on the contact surface T calculated by numerical calculation based on the resistance value of each brush main body piece 15, the performance curve of the motor M, or the like. It is desirable that the position is optimal for switching the type of the piece 15. Further, the latter term means a period from the time when the contact surface T reaches the set position to the time when the brush body 11 is consumed.

  Furthermore, in the brush body 11 according to the present embodiment, the region where the brush body piece 15 having a lower resistance value appears on the contact surface T increases as the contact surface T recedes due to the above-described configuration. The region where the brush body piece 15 having a higher value appears is reduced. That is, in the present embodiment, the configuration of the brush body 11 is such that as the contact surface T recedes, the region where the brush body piece 15 having a lower resistance value appears on the contact surface T increases. The region where the brush body piece 15 having a higher height appears is reduced. Here, the region is a range occupied by each brush body piece 15 on the contact surface T.

More specifically, with the above-described configuration, as the contact surface T is initially retracted, the region where the middle resistance piece 15b appears on the contact surface T increases, while the high resistance piece 15c. The area where appears is reduced. In other words, during the initial stage, the contact surface T is in the state shown in FIG. 4A at a certain time, and when the contact surface T is somewhat retracted from this time, the state transitions to the state shown in FIG.
Similarly, in the latter period, as the contact surface T moves backward, the region where the low resistance piece 15a appears on the contact surface T increases, while the region where the medium resistance piece 15b appears decreases. That is, during the latter period, the contact surface T is in the state shown in FIG. 4C at a certain time, and when the contact surface T is somewhat retracted from this time, the state transitions to the state shown in FIG.

  The change in the contact surface T described above is realized by the arrangement pattern of each brush body piece 15 in the brush body 11 described above (that is, the arrangement pattern of each brush body piece 15 shown in FIG. 3). Is.

Next, an example of a method for manufacturing the brush body 11 having the above configuration will be described with reference to FIGS.
When manufacturing the brush main body 11 having the above-described configuration, a mold 8 is used (see, for example, FIG. 7A). The molding die 8 is formed with a feeding groove 8a, and brush powder which is a material of the brush body 11 is fed into the feeding groove 8a. Further, the upper pressing pieces 9a to 9c and the lower pressing piece 10 are inserted into the charging groove 8a, and the brush powder is pressed between the pieces to form the brush body piece 15. The upper pressing pieces 9a to 9c are prepared for the types of brush main body pieces 15 (three types in this embodiment), and the upper pressing pieces 9a to 9c have shapes corresponding to the layers formed by the brush main body pieces 15. have. Further, the upper end surface of the lower pressing piece 10 is curved in an arc shape.

  The manufacturing procedure of the brush body 11 will be described. With the lower pressing piece 10 inserted from the lower opening of the charging groove 8a, the brush powder for the high resistance piece 15c is charged from the upper opening of the charging groove 8a (FIG. 7). (See (a)). After feeding the brush powder, the upper pressing piece 9a for forming the layer of the high resistance piece 15c is inserted into the feeding groove 8a, and the brush powder is pressurized between the pieces to form the layer of the high resistance piece 15c ( (Refer FIG.7 (b)). Thereafter, the upper pressing piece 9a is pulled out, and the brush powder for the medium resistance piece 15b is put on the layer of the high resistance piece 15c. Thereafter, the middle resistance piece 15b layer and the low resistance piece 15a layer are formed by the same procedure (see FIGS. 7C and 7D). Thus, the brush body 11 having a three-layer structure is completed, and finally the pigtail 14 is attached after being removed from the mold 8.

<< Effectiveness of Brush Device S According to the Present Embodiment >>
In the brush device S according to the present embodiment, the brush body 11 is configured by laminating a plurality of brush body pieces 15 having different resistance values. In the configuration of the brush body 11, the brush body piece 15 having a higher resistance value appears on the contact surface T on the downstream side as viewed from the rotation direction of the commutator 4 than the brush body piece 15 having the lower resistance value. As the contact surface T is retracted, the area of the brush body piece 15 having a lower resistance value on the contact surface T increases, and the brush body piece 15 having a higher resistance value appears. The area is reduced. With such a configuration, it is possible to stabilize the performance of the motor M while realizing good rectification and suppressing spark discharge regardless of the degree of wear of the brush body 11.

  More specifically, in the brush device S according to the present embodiment, the configuration of the brush body 11 is such that the brush body piece 15 having a higher resistance value on the contact surface T is higher than the brush body piece 15 having a lower resistance value. The configuration is such that it appears on the downstream side when viewed from the rotational direction of the commutator 4. With such a configuration, the brush main body 11 abuts on each commutator piece 4a at a lower resistance portion in the early stage of commutation, and in the later stage of commutation, prioritizing suppression of spark generation, The brush body 11 abuts at a higher resistance portion. That is, resistance rectification occurs in the later stage of rectification, and as shown in FIG. 5, the current change compared to the conventional brush body (brush body with a uniform resistance distribution as viewed from the rotation direction of the commutator 4). Becomes moderate. Therefore, the spark discharge generated by the rapid current change is suppressed, and good rectification is realized. Furthermore, as a result of realizing good rectification, secondary effects such as improved durability of the brush body 11 and reduction of noise and electromagnetic noise are also exhibited.

  On the other hand, as the wear of the brush body 11 progresses, the contact force of the brush body 11 with respect to the commutator 4 is reduced by gradually reducing the inelastic force (elastic force) by the biasing spring 13, and the brush body 11 and the commutator are reduced. The contact resistance with 4 increases. In the conventional brush device, the motor performance (specifically, the output characteristics) is lowered as the contact resistance increases. On the other hand, in the brush device S according to the present embodiment, as the contact surface T recedes, the region where the brush body piece 15 having a lower resistance value appears on the contact surface T increases. The area where the brush body piece 15 having a higher is appearing is reduced. That is, in the brush device S according to the present embodiment, the influence of the contact pressure of the brush body 11 with respect to the commutator 4 being reduced due to wear of the brush body 11 is affected by the portion of the brush body 11 that contacts the commutator 4. It becomes possible to cancel by reducing the resistance.

Furthermore, in this embodiment, the region where the brush body piece 15 having a lower resistance value appears on the contact surface T gradually appears in accordance with the amount of retreat of the contact surface T (in other words, the amount of wear of the brush body 11). The brush body 11 is configured so that the region where the brush body piece 15 having a higher resistance value appears gradually decreases. That is, in a conventional brush device (for example, a brush device whose resistance value changes stepwise in the thickness direction), the resistance value (that is, the contact resistance value) of the portion appearing on the contact surface T in the brush body 11. Changes discretely, but in the brush device S according to the present embodiment, it changes continuously according to the retraction amount of the contact surface T. As a result, as shown in FIG. 6, the contact resistance value is kept constant regardless of the amount of wear of the brush body 11. Therefore, in this embodiment, it is possible to avoid a sudden change in the performance of the motor.
As a result, in the present embodiment, it is possible to stabilize the performance of the motor M while realizing good rectification and suppressing spark discharge regardless of the degree of wear of the brush body 11.

<< Other Embodiments >>
In the above embodiments, the brush device and the motor of the present invention have been mainly described. However, the above embodiment is for facilitating the understanding of the present invention, and does not limit the present invention. The present invention can be changed and improved without departing from the gist thereof, and the present invention includes the equivalents thereof.

  For example, in the above embodiment, each brush body piece 15 is composed of graphite containing copper as a component. However, the present invention is not limited to this, and each brush body piece 15 is made of synthetic resin such as phenol resin or epoxy resin, carbon-based material such as carbon nanotube or carbon fiber, zinc, manganese, nickel, molybdenum compound (for example, (Molybdenum disulfide) or the like can be used as appropriate.

In the above embodiment, the brush body 11 having the three-layer structure has been described. That is, the brush body 11 according to the above-described embodiment may be a brush body 11 having a multilayer structure of four or more layers, in which the low resistance piece 15a, the middle resistance piece 15b, and the high resistance piece 15c are layered. Good.
If the brush body 11 has a two-layer structure, the configuration can be simplified as compared with the above-described embodiment (the brush body 11 having a three-layer structure), but the adjustment of the contact resistance value becomes rough. On the other hand, as the number of layers of the brush body pieces 15 constituting the brush body 11 increases, the contact resistance value can be finely adjusted, but the manufacturing becomes difficult. In consideration of the precision of adjusting the contact resistance value and the simplicity of the structure, it is preferable that the number of layers formed on the brush body 11 is about three.

In the above embodiment, the high resistance piece 15c and the medium resistance piece 15b appear on the contact surface T in the initial period from when the brush body 11 starts to be consumed until the brush body 11 is consumed. At T, the medium resistance piece 15b and the low resistance piece 15a appear. That is, in the above-described embodiment, the brush body pieces 15 appearing on the contact surface T are two types during the initial period and the latter period. However, the present invention is not limited to this. The main body piece 15 may appear on the contact surface T.
In the above embodiment, the downstream end of the boundary surface B1 between the layer of the high resistance piece 15c and the layer of the middle resistance piece 15b, so that two types of brush body pieces 15 appear on the contact surface T, The upstream end of the boundary surface B2 between the layer of the medium resistance piece 15b and the layer of the low resistance piece 15a is positioned at the same position in the thickness direction of the brush body 11. However, the present invention is not limited to this, and the downstream end of the boundary surface B1 and the upstream end of the boundary surface B2 may be located at different positions in the thickness direction.

  Moreover, in said embodiment, the arrangement pattern of the brush main-body piece 15 shown in FIG. 3 was employ | adopted. That is, the layer of the high resistance piece 15c is formed at the corner portion of the brush body 11 that is located on the downstream side when viewed from the rotation direction of the commutator 4 and on the front end side in the thickness direction. The layer of the medium resistance piece 15b is adjacent to the layer of the high resistance piece 15c, and is located downstream from the corner located on the upstream side in the thickness direction and on the front end side in the thickness direction. It was supposed that it was formed diagonally toward the part located in the area. The layer of the low resistance piece 15a is adjacent to the layer of the middle resistance piece 15b on the rear end side in the thickness direction, and is formed so that the length in the thickness direction becomes shorter from the upstream side to the downstream side when viewed from the rotation direction. It was decided that The said structure is comparatively simple as a structure for stabilizing the performance of a motor, implement | achieving favorable commutation | regulation irrespective of the abrasion degree of a brush main body, suppressing spark discharge. That is, if it is said structure, it will become possible to acquire the effect of this invention by a comparatively simple structure. However, the above arrangement pattern is merely an example, and other arrangement patterns may be used.

  In the above embodiment, the arrangement pattern of the brush body pieces 15 in the rotation direction of the commutator 4 and the thickness direction of the brush body 11 has been described. That is, in the above embodiment, the distribution of each brush body piece 15 in the brush body 11 is defined in the above two directions. However, the present invention is not limited to this, and as shown in FIGS. 8 to 11, the distribution of each brush body piece 15 is defined in three directions including the height direction of the brush body 11 in the above two directions. (That is, the arrangement pattern of each brush body piece 15 may be determined three-dimensionally). 8 to 11 are configuration diagrams of the brush body 11 in which the respective brush body pieces 15 are three-dimensionally distributed. FIG. 8 is a diagram when the brush body 11 is viewed from the upper side in the height direction. 9 is a diagram when viewed from the front side in the thickness direction, FIG. 10 is a diagram when viewed from the upstream side in the rotational direction of the commutator 4, and FIG. 11 is a diagram in the rotational direction. It is a figure when it sees from the downstream.

1 shaft, 2 coil, 3 iron core, 4 commutator, 4a commutator piece,
5 magnets, 6 housings,
7 Bearing, 8 Mold, 8a Loading groove, 9a, 9b, 9c Upper pressing piece,
10 Lower pressing piece, 11 Brush body, 12 Storage box,
13 bias spring, 14 pigtail,
15 brush body piece, 15a low resistance piece, 15b medium resistance piece, 15c high resistance piece,
B1, B2 boundary surface, M motor, S brush device, T contact surface

Claims (5)

A brush device comprising a brush body having a contact surface that contacts a commutator rotating in one direction at a front end in a thickness direction and biased to contact the commutator at the corresponding contact surface. ,
The brush body is configured by laminating a plurality of brush body pieces having different resistance values from each other, and the contact surface is worn so as to recede along the thickness direction,
In the configuration of the brush body, the brush body piece with the higher resistance value appears on the downstream side when viewed from the rotation direction of the commutator than the brush body piece with the lower resistance value on the contact surface. As the contact surface is retracted, a region where the brush body piece having a lower resistance value appears on the contact surface increases, and the brush body piece having a higher resistance value appears. The brush device is characterized in that the area of the brush is reduced. The brush body includes a plurality of brush body pieces, a first brush body piece, a second brush body piece having a larger resistance value than the first brush body piece, and the resistance more than the second brush body piece. It is composed of a third brush body piece with a large value stacked in layers,
At the beginning of the period from the start of consumption of the brush body to the end of consumption, the second brush body piece appears on the upstream side when viewed from the rotational direction on the contact surface, and the third brush body piece on the downstream side. As the contact surface retreats, the area where the second brush body piece appears on the contact surface increases, and the area where the third brush body piece appears decreases,
In the latter part of the period, the first brush body piece appears on the upstream side as viewed from the rotation direction on the contact surface, the second brush body piece appears on the downstream side, and the contact surface moves backward. 2. The brush device according to claim 1, wherein a region where the first brush main body piece appears on the contact surface increases and a region where the second brush main body piece appears decreases. The layer of the third brush body piece is formed in a corner portion of the brush body that is located on the downstream side when viewed from the rotation direction and on the front end side in the thickness direction,
The layer of the second brush body piece is adjacent to the layer of the third brush body piece in the brush body, from the corner portion located upstream of the rotation direction and on the front end side in the thickness direction. , Formed at an angle toward the downstream side and the portion located in the central portion in the thickness direction,
The layer of the first brush body piece is adjacent to the layer of the second brush body piece on the rear end side in the thickness direction in the brush body, and as it goes from the upstream side to the downstream side as seen from the rotation direction, The brush device according to claim 2, wherein the brush device is formed so that a length in a thickness direction is shortened. The boundary surface between the layer of the third brush body piece and the layer of the second brush body piece, and the boundary surface between the layer of the second brush body piece and the layer of the first brush body piece are in the rotation direction. The end on the downstream side as viewed from the side is inclined so as to be located on the rear side in the thickness direction with respect to the upstream end,
The downstream end of the boundary surface between the layer of the third brush body piece and the layer of the second brush body piece, and the boundary surface between the layer of the second brush body piece and the layer of the first brush body piece The brush device according to claim 3, wherein the upstream end is located at the same position in the thickness direction. A commutator rotating in one direction;
A brush device including a brush body that has a contact surface that contacts the commutator at a front end in the thickness direction and is biased to contact the commutator at the contact surface;
A motor equipped with
The brush body is configured by laminating a plurality of brush body pieces having different resistance values from each other, and the contact surface is worn so as to recede along the thickness direction,
In the configuration of the brush body, the brush body piece with the higher resistance value appears on the downstream side when viewed from the rotation direction of the commutator than the brush body piece with the lower resistance value on the contact surface. As the contact surface is retracted, a region where the brush body piece having a lower resistance value appears on the contact surface increases, and the brush body piece having a higher resistance value appears. A motor characterized by having a configuration in which the area being reduced decreases.

Images