JP3736743B2 - Brush manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention belongs to the technical field of a brush that is in sliding contact with a commutator of a DC rotating electric machine such as a DC motor or a DC generator.
[0002]
[Prior art]
(Old technology)
As a conventional technique, Japanese Patent Application Laid-Open No. 9-49478 discloses a multilayer brush in which a plurality of different types of brush materials having different electrical conductivities are laminated. The brush main body described in the embodiment of the publication is integrally formed by joining a thick high conductive member and a thin low conductive member.
[0003]
The publication does not mention the attachment of the lead wire connected to the brush body, but when the lead wire is inserted into the brush body from the highly conductive member side, the connection resistance is low and good connection characteristics. Is obtained. However, conversely, when a lead wire is inserted into the brush body from the low conductive member side, the connection resistance between the two becomes high, resulting in inconvenience. That is, as shown in FIG. 7, since the lead wire 103 inserted into the brush body 100 from the low conductive member 101 side is in contact with the low conductive member 101, the connection resistance is increased at this portion. The efficiency of the DC rotating electric machine equipped with such a brush is lowered, and the performance is lowered. Moreover, due to the Joule heat generated by the connection resistance, an overheating problem may be caused.
[0004]
(Improved technology)
In order to avoid such inconvenience, as shown in FIG. 8, it is conceivable that the lead wire 103 is inserted deeper into the brush body 100 to reach the portion of the highly conductive member 102. The low-conductivity member 101 is clung around the periphery of the insertion. As a result, the connection resistance also increases at that portion, and some disadvantages as described above occur. In addition, the connection resistance varies depending on how the low-conductive member 101 is attached to the lead wire 103, and as a result, there is a disadvantage that a stable performance of the DC rotating electric machine cannot be obtained. Then, the case where the lead wire 103 is inserted into the brush body 100 from the low conductive member 101 side in this way is unavoidable in the handling of the lead wire 103.
[0005]
(Conventional technology)
Therefore, in order to prevent the connection resistance from becoming too large in such a case, there is a conventional brush disclosed in Japanese Patent Laid-Open No. 2-86081 and a method for manufacturing the same. That is, the publication discloses a brush in which a portion where a lead wire is inserted does not have a low conductive member, and the portion is covered with a high conductive member in a columnar shape (such as a columnar shape or a prismatic shape). According to this prior art, the lead wire does not touch the low conductive member at all and is embedded only in the high conductive member, so that the lead wire is inserted into the brush body from the low conductive member side, There is an effect that the connection resistance of the lead wire does not increase.
[0006]
[Problems to be solved by the invention]
However, depending on the prior art, it is necessary to eliminate the low-conductivity member only in part and form the high-conductivity member in a columnar shape. Therefore, as disclosed in the publication, the brush body molding process is performed twice. The powder material must be pressed and divided. As a result, it is unavoidable that the manufacturing process becomes complicated and man-hours increase, resulting in a significant increase in cost.
[0007]
  Therefore, the present invention provides a brush that is stable without increasing the connection resistance of the lead wire while the lead wire is inserted into the brush body from the low conductive member side.By manufacturing with a simpler manufacturing process than beforeProviding at low cost is a problem to be solved.
[0008]
[Means for Solving the Problems]
  In order to solve the above problems, the inventors haveBrush manufacturing methodWas invented.
[0009]
  First, the structure of a brush to which the manufacturing method of the present invention is applied will be described. Of the present inventionThe brush includes a brush main body in which a high conductive member and a low conductive member are bonded to each other, and a lead wire having one end embedded in the brush main body, and has the following structural features. First, the low-conductivity member has a thin plate shape and is joined to the surface portion on the sliding contact side of the side surfaces of the high-conductivity member. Next, the lead wire is embedded in the surface portion where the low conductive member is not connected on the side opposite to the sliding contact surface among the side surfaces of the high conductive member.
[0010]
Here, the low conductive member is assumed to be a thin plate, but it is sufficient if it has a relatively thin plate or layer shape compared to the thickness of the brush, and the thickness of the low conductive member is not necessarily constant. There is no need. In addition, it is desirable that the low conductive member covers one surface of the high conductive member over the entire width of the brush body, but this is not necessarily required.
[0011]
Furthermore, it is desirable that the low-conductive member is present from one surface of the brush body to the portion corresponding to at least the maximum wear allowance of the brush body from the sliding surface side that is in sliding contact with the commutator of the rotating electrical machine. It is not limited to this. Conversely, even if the low-conductive member is slightly in contact with the embedded lead wire, it is within the scope of this means.
[0012]
The lead wire is embedded in the surface of the brush body opposite to the sliding surface. However, the lead wire is not limited to the surface of the brush body, and is considerably deeper in the brush body. It may be buried. Even if it is on the side opposite the sliding contact surface, the lead wire does not necessarily have to be embedded in the end (opposite end) opposite to the sliding contact surface. If that's the case,
[0013]
ReThe lead wire is embedded only in the high conductivity member and not in the low conductivity member, so the lead wire is connected to the brush body while the lead wire is inserted from the low conductivity member side. Resistance does not increase. In addition, the surface portion of the highly conductive member in which one end of the lead wire is embedded is not formed in a columnar shape and surrounded by the low conductivity member, but the sliding surface of one surface of the highly conductive member. Only the side is covered with a thin plate-like low-conductivity member. Therefore, the connection resistance of the lead wire is not only lower than that of the prior art, but also has less variation than the prior art and maintains a more stable value.
[0014]
  ThereforeLowAlthough the lead wire is embedded in the brush body from the side where the conductive member is disposed, the connection resistance of the lead wire is lower than that of the prior art, and the variation in the resistance value is also smaller.Yes.As a result, the brush of this means has an effect of generating less Joule heat and less likely to cause a problem due to overheating. Not only that, the performance of the rotating electrical machine using the brush of this means is improved, and further, the variation in the performance of the rotating electrical machine is reduced..
[0015]
  Moreover,thisThe brush can be easily manufactured by a simpler manufacturing process than the conventional technology, so the manufacturing cost is reduced and it can be provided at a lower cost than the conventional technology.The
[0016]
Also, unlike the manufacturing process in which the low-conductivity member and the high-conductivity member are pressed and divided in two steps in the prior art, a manufacturing process in which the low-conductivity member and the high-conductivity member are pressed together in one punch is taken. be able to. As a result, since the low conductive member and the high conductive member are more firmly bonded to each other, peeling between them is less likely to occur, and the effect of improving the reliability of the brush is also obtained.
[0017]
  This brush is manufactured using the following manufacturing method.That is, the brush body is filled with a high-conductivity powder in a female mold with a step of a predetermined height on the surface, and the low-conductivity powder is roughly plate-like in the lower part of the surface of the high-conductivity powder. Squeeze and sinter bothManufactured.
[0018]
  When this manufacturing method is adopted,In the manufacturing process, the material powder forming the brush body is pressed only once, so the manufacturing process is simplified compared to the conventional technology that requires the pressing process twice, and the manufacturing cost is reduced and the manufacturing cost is reduced. The As a result, the brush of this means is less expensive than the brush produced by the prior art production method.The
[0020]
  In a preferred embodiment,The highly conductive powder is once filled flat in a female mold, and then the surface portion is formed with a step difference from one end to the other end.
[0021]
  That is,In forming the step on the surface of the highly conductive member, after the highly conductive powder is once filled flat in the female mold as described above, the surface portion is moved halfway from one end to the other end. . Therefore, by attaching a movable piece to the female mold as will be described later in the section of Example 1, or by thrusting the movable piece from above the female mold, the surface portion of the highly conductive powder can be relatively easily obtained. A step can be formed.
[0022]
  ThereforeYongA step can be easily formed on the surface portion of the highly conductive powder.
[0042]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the brush of the present invention are clearly and fully described in the following examples so as to provide a practicable understanding for those skilled in the art.
[0043]
[Example 1]
(Configuration of Example 1)
The brush as Example 1 of the present invention is a component constituting a DC rotating electric machine (not shown), and is in sliding contact with a commutator (not shown). As shown in FIG. 1, the brush of this embodiment includes a block-shaped brush body 10 and a lead wire 3 having one end 31 embedded in the brush body 10.
[0044]
That is, the brush body 10 includes a high conductivity member 2 and a low conductivity member 1 integrally joined to the high conductivity member 2. Here, the high conductive member 2 is a member made of a sintered alloy containing copper as a main component and having high electrical conductivity, and may be called a low resistivity member. On the other hand, the low-conductivity member 1 is a member having a low electrical conductivity, which is made of a sintered material containing graphite as a main component and containing additive particles such as a binder, and may be called a high resistivity member.
[0045]
A sliding contact surface 11 that is in sliding contact with a commutator (not shown) of the brush body 10 is formed by the end surfaces of both the high conductive member 2 and the low conductive member 1. On the contrary, the base end face 12 pressed and urged by a spring (not shown) is formed facing away from the sliding contact face 11 and is formed only from the end face of the highly conductive member 2.
[0046]
The low conductive member 1 has a thin plate shape with a substantially constant thickness, and is joined to the surface portion 21 on the sliding contact surface 11 side of the side surface of the high conductive member 2. On the other hand, the lead wire 3 is embedded in the surface portion 22 to which the low conductive member 1 is not connected on the side opposite to the sliding contact surface 12 among the side surfaces of the high conductive member 2. The low conductive member covers one surface of the high conductive member 2 over the entire width of the brush body 10 (the depth direction in FIG. 1). Further, the low-conductive member 1 is formed on one surface of the brush body 10 at a portion slightly exceeding the maximum wear allowance of the brush body from the sliding contact surface 11 side that is in sliding contact with the commutator (not shown) of the rotating electrical machine. Extend to. The low conductive member 1 is bonded to the high conductive member 2 with a predetermined distance from the lead wire 10 embedded in the brush body 10.
[0047]
The lead wire 3 is a strand (stranded wire) obtained by twisting a large number of thin copper wires, and is also commonly called a pigtail. One end 31 of the lead wire 3 embedded in the highly conductive member 2 of the brush body 10 is formed by cutting off the tip surface, and is firmly joined to the highly conductive member 2 and fixed to the brush body 10. Yes. One end 31 of the lead wire 3 is embedded in the highly conductive member 2 at a predetermined depth from the surface portion 22 of the brush body 10 on the side opposite to the sliding contact surface 11. Moreover, the lead wire 3 is embedded in the highly conductive member 2 at a predetermined distance from the base end surface 12 even on the side opposite to the sliding contact surface 11.
[0048]
(Operational effect of Example 1)
Since the brush of the present embodiment is configured as described above, the following operational effects are exhibited.
[0049]
First, since the lead wire 3 is embedded only in the high conductive member 2 and is not embedded in the low conductive member 1, the lead wire 3 is connected to the brush body 10 from the side where the low conductive member 1 is present. The connection resistance of the lead wire 3 does not increase while being inserted. In addition, the surface portion 22 of the highly conductive member 2 in which the one end 31 of the lead wire 3 is embedded is not formed in a columnar shape and surrounded by the low conductive member 1 as in the prior art. That is, only the sliding contact surface 11 side of the one surface of the high conductive member 2 on which the lead wire 3 is inserted is only covered with the thin plate-like low conductive member 1. Therefore, the connection resistance of the lead wire 3 is not only lower than that of the above-described conventional technique, but also has less variation than the conventional technique and maintains a more stable value.
[0050]
Therefore, according to the brush of the present embodiment, the lead wire 3 is embedded in the brush body 10 from the side where the low conductive member 1 is disposed, but the connection resistance of the lead wire 3 is lower than that of the prior art. There is an effect that there is less variation in resistance value. As a result, the brush of this embodiment has an effect that Joule heat is generated less and it is difficult to cause problems due to overheating. In addition, there is an effect that the performance of the rotating electrical machine adopting the brush of this means is improved, and further, the variation in the performance of the rotating electrical machine is reduced.
[0051]
Second, as described in the next section, the brush of the present embodiment can be easily manufactured by a simpler manufacturing process than the prior art, so that the manufacturing cost is reduced and can be provided at a lower price than the prior art. There is also an effect.
[0052]
Third, unlike the manufacturing process in which the low-conductivity member and the high-conductivity member in the prior art are pressed in two steps, the low-conductivity member 1 and the high-conductivity member 2 are pressed together in one punch. In this manufacturing process, the brush of this example is manufactured. As a result, the low-conductive member 1 and the high-conductive member 2 are more firmly joined to each other, so that peeling between the two and 1 is less likely to occur. According to the brush of this embodiment, the reliability is high. The effect of improving is also acquired.
[0053]
(Production process of Example 1)
As shown in FIGS. 2 (a) to 2 (f), the brush of this example has a high conductivity powder 2 ′ that is a material of the high conductivity member 2 and a low conductivity that is a material of the low conductivity member 1. Powder 1 'is shape | molded by the one punch (the process of pressing and hardening once). Thereafter, the molded product is fired in a state where one end 31 of the lead wire 3 is embedded, and the brush body 10 is configured as a sintered body. That is, the brush body 10 is filled with the high conductivity powder 2 ′ in the female mold 4 with steps of a predetermined height on the surfaces 21 ′ and 22 ′, and the lower one of the surfaces of the high conductivity powder 2 ′. After the portion 21 'is filled with the low conductive powder 1' in a plate shape, both 1 'and 2' are pressed and sintered.
[0054]
More specifically, the highly conductive powder 2 ′ is once flatly filled into the recess 40 of the female mold 4 as shown in FIG. Thereafter, as shown in FIGS. 2C to 2D, the movable piece 41 protrudes from one end of the female mold 4 with a predetermined stroke and then returns, so that the surface portion of the highly conductive powder 2 ′ is moved from one end to the other. The surface 21 ', 22' is formed with a step difference toward the end halfway. Note that after the movable piece 41 blocks the surface 21 ′, 22 ′ may be replenished to form a step. Next, as shown in FIG. 2 (e), the lower surface 21 'of the high conductive powder 2' is filled with the low conductive powder 1 'with a thickness corresponding to the level difference, thereby reducing the low conductive powder 1'. And the surface of the highly conductive powder 2 'is almost flat at almost the same height. After that, the male mold 5 holding the one end 31 of the lead wire 3 protruding is fitted and pushed into the female mold 4 from above, and the one end 31 of the lead wire 3 is pushed into the highly conductive powder 2 ' The conductive powder 1 'and the highly conductive powder 2' are pressed together.
[0055]
Thus, the high conductive powder 2 ′ and the low conductive powder 1 ′ are integrally molded by one punch to form a molded body, and the one end 31 of the lead wire 3 is fixed in the compacted high conductive powder 2 ′. Thereafter, the molded product is taken out from the female die 4 and fired in a heating furnace in a state where one end 31 of the lead wire 3 is buried, thereby constituting the brush body 10 which is a sintered body.
[0056]
In the above manufacturing process, the material powders 1 ′ and 2 ′ forming the brush body 10 are pressed only once. Therefore, in this embodiment, the manufacturing process is simplified, the number of steps is reduced, and the manufacturing cost is reduced as compared with the conventional technique that requires the step of pressing twice. As a result, the brush of the present embodiment has an effect that it is cheaper than the brush manufactured by the manufacturing method of the prior art. Further, for the same reason, the bonding between the high conductive powder 2 ′ and the low conductive powder 1 ′ becomes strong, and the low conductive member 1 becomes difficult to peel off from the high conductive member in the brush as a product. This has the effect of improving the reliability.
[0057]
(Modification 1 of Example 1)
As a modified embodiment 1 of the present embodiment, as shown in FIGS. 3A to 3D, it is possible to implement a brush whose manufacturing process is slightly different from that of the first embodiment. That is, in the manufacturing process of the brush according to this modified embodiment, the highly conductive powder 2 ′ is once flatly filled in the female mold 4 as shown in FIG. 3A and then shown in FIG. Thus, a part of the surface is covered and further filled so that the surface is formed with a step. The subsequent steps are the same as the manufacturing steps of Example 1 described above, as shown in FIGS.
[0058]
In the manufacturing process according to this modification, when forming a step on the surface of the highly conductive member 2, the highly conductive powder 2 'is once flatly filled into the female mold 4 as described above. Thereafter, a part of the surface thereof is covered and further filled with the highly conductive powder 2 ′, and the surfaces 21 ′ and 22 ′ of the highly conductive powder are formed with a step. Therefore, the movable piece 41 (see FIG. 2) is not required for the female mold 4, the configuration of the female mold 4 is simplified, and the highly conductive powder 2 ′ is slightly easier than the manufacturing process in the first embodiment. Steps can be formed on the surfaces 21 'and 22'.
[0059]
Therefore, according to the brush of this modification, in addition to the effect of the first embodiment, there is an effect that steps can be formed on the surfaces 21 ′ and 22 ′ of the highly conductive powder 2 ′ relatively easily. is there.
[0060]
In the brush of this modification, as shown in FIG. 2B, the edge of the highly conductive powder 2 ′ accumulated later is naturally broken, so the surfaces 21 ′ and 22 ′ of the highly conductive powder 2 ′. The step is not a step, but a slightly rounded slope. Therefore, in the brush as a product, the stress concentration is slightly relieved in the corner portion of the low conductive member 1, and the strength is increased.
[0061]
(Modification 2 of Example 1)
As a modification 2 of the present embodiment, a part of the entire circumference of the lead wire 3 is a surface portion where the low conductive member 1 is not connected on the side opposite to the sliding contact surface 11 of the side surface of the high conductive member 2. The implementation of the brush embedded in 22 is possible. In other words, in the brush of this modification, more than half of the entire circumference of the lead wire 3 is embedded in the surface portion 22 with the highly conductive member 2, and the other portion of the lead wire 3 is a low conductive member. 1 to the brush body 10.
[0062]
In this modification, the resistance of the portion of the lead wire 3 surrounded by the high conductive member 2 is much smaller than that of the portion surrounded by the low conductive member 1, so that fairly good conductivity can be obtained. . Then, even if the conductivity of the brush of Example 1 is not as good as that of the brush, the conductivity close to that can be obtained. Therefore, according to the brush of this modification, the effect similar to that of Example 1 can be obtained. In addition, there is an effect that the tolerance regarding the formation range of the plate-like low-conductivity member 1 is increased, and it can be manufactured at a lower cost.
[0063]
Therefore, according to the present modification, an effect can be obtained that can be manufactured at a lower cost while an effect equivalent to or equivalent to that of the first embodiment is obtained.
[0064]
[Example 2]
(Configuration and effect of Example 2)
As shown in FIG. 4, the brush as the second embodiment of the present invention has a configuration similar to that of the first embodiment described above, but has a configuration different from that of the first embodiment in the following two points. Yes.
[0065]
First, one end 31 of the lead wire 3 is embedded in the highly conductive member 2 much deeper than in the first embodiment. Therefore, the connection resistance between the lead wire 3 and the highly conductive member 2 is smaller than that of the first embodiment, the resistance loss is further reduced and the overheating is difficult, and the rotation using the brush of this embodiment is adopted. There is an effect that the performance of the electric machine (not shown) is improved.
[0066]
Secondly, corners disappear from the portion of the thin plate-like low-conductivity member 1 that contacts the high-conductivity member 2, and instead of the curved surface R having an appropriate curvature, the low-conductivity member 1 and the high-conductivity member 2 Are joined together. As a result, stress concentration such as thermal stress is greatly relieved around the curved surface R, so that the strength of the brush of this embodiment is further improved.
[0067]
Furthermore, since the brush of the present embodiment can be manufactured by a simple manufacturing process as described in the next section, there is an effect that it can be provided at a lower cost than that of the first embodiment.
[0068]
These effects are all due to the following manufacturing process.
[0069]
(Manufacturing process and effect of Example 2)
As shown in FIGS. 5A to 5C, the brush body 10 (see FIG. 4) covers the lower end of the female mold 4 from one end to the middle portion and applies the low-conductive powder 1 ′ with a predetermined thickness. After filling, the female mold 4 is filled with the highly conductive powder 2 'from above, and then both 1' and 2 'are pressed and sintered.
[0070]
That is, first, as shown in FIG. 5A, the low-conductive powder 1 'is filled with a predetermined thickness so as to cover from one end to the middle of the bottom surface of the female die 4. The range in which the low-conductive powder 1 'is spread with a constant thickness is equal to the maximum brush wear allowance. At this time, the edge portion of the low conductive powder 1 ′ in the middle portion of the female mold 4 is formed by a curved surface having an appropriate curvature that is naturally broken by gravity and is not formed at a right angle. Further, the edge of the low conductive powder 1 ′ collapses, so that the surface (lower surface) of the low conductive powder 1 ′ extends to a range slightly exceeding the brush wear allowance. However, an appropriate clearance is formed between the low conductive powder 1 ′ and the lead wire 3 so that the low conductive powder 1 ′ does not directly contact the lead wire 3.
[0071]
Next, as shown in FIG. 5 (b), the female die 4 is covered with one end 31 of the lead wire 3 and the low conductive powder 1 ′, which protrudes considerably from the bottom surface of the female die 4 and is held vertically. Highly conductive powder 2 'is filled. At this time, unlike the case where the lead wire 3 is pushed into the already filled high conductive powder 2 ′ as in the first embodiment, the high conductive powder 2 ′ covers the one end 31 of the lead wire 3 and conversely. Filled. Therefore, even if one end 31 of the lead wire 3 protrudes longer than in the first embodiment, the high conductive powder 2 ′ is sprinkled from above, so that the high conductive powder is comfortably provided around the one end 31 of the lead wire 3. 2 'will be filled. As a result, the high conductive powder 2 ′ covers the periphery of the one end 31 of the lead wire 3 and the surface of the low conductive powder 1 ′, and the upper surface of the high conductive powder 2 ′ is naturally flat.
[0072]
Finally, as shown in FIG. 5 (c), pressing is performed with the male mold 5 fitted to the female mold 4, and the low conductive powder 1 'and the high conductive powder 2' are compacted. Thereafter, the molded body is taken out from the female mold 4 and sintered to form the brush (see FIG. 4) of the present embodiment as described above.
[0073]
In the present embodiment, as in the first embodiment and the modified embodiment 1 described above, since the pressing process is only once, the manufacturing process is simplified and the man-hour is reduced compared to the conventional technique that requires the pressing process twice. The manufacturing cost is reduced. Moreover, unlike the above-described first embodiment and its modification 1, the low-conductivity powder 1 ′ is first filled in a predetermined range of the female mold 4 and then the high-conductivity powder 2 ′ is filled into the female mold 4. Therefore, a step is naturally formed on the downward surface of the highly conductive powder 2 ′. As a result, the brush of the present embodiment is not only cheaper than the brush manufactured by the manufacturing method of the prior art, but also more effective than the brush of the first embodiment and the modified embodiment 1 described above. Arise.
[0074]
(Modification 1 of Example 2)
As a modified embodiment 1 of the present embodiment, it is possible to implement a brush having a configuration corresponding to the modified embodiment 2 of the first embodiment. Also according to this modification, the same effect as that of Modification 2 for Example 1 can be obtained.
[0075]
(Other effects of the above embodiment)
In each of the embodiments described above, a high resistivity powder for forming the low conductive member (low conductive portion) 1 and a low resistivity powder for forming the high conductive member (high conductive portion) 2 are laminated. After sequentially depositing in the direction, compression molding is performed at the same time.
[0076]
In this way, both members are formed by thermal or mechanical energy at the time of simultaneous molding as compared to molding them separately or molding one and then depositing the other and molding again. At the boundary portion 100 (see FIG. 6), the low resistivity powder and the high resistivity powder are mixed and an intermediate composition is generated at the boundary portion. As a result, it is possible to satisfactorily suppress the occurrence of cracks along the boundary due to the thermal cycle acting on the brush.
[0077]
The technique and effect of simultaneous molding after laminating a plurality of powder layers having different compositions from each other are not limited to those in Examples 1 and 2, but a brush having a plurality of powder layers laminated with different compositions. It can be applied to all molding.
[0078]
(Modification)
In the above-described Examples 1 and 2, the low conductive member 1 does not cover the entire left side surface of the brush body 10 in FIG. 1, and the thickness direction (left and right direction in FIG. 1) of the portion near the lead wire 3 is All are occupied by the highly conductive member 2.
[0079]
However, as a modification, even if a layer of the low conductive member 1 thinner than the low conductive member 1 shown in FIG. 1 (left and right direction in FIG. 1) is provided in the vicinity of the lead wire 3, the lead wire 3 and the brush It is clear that the contact resistance with the main body 10 can be reduced and the resistance loss (due to local current concentration) of the brush main body 10 in the vicinity of the lead wire 3 can be reduced.
[0080]
[Example 3]
Another embodiment of the brush of the present invention will be described below with reference to FIG.
[0081]
The brush of this embodiment has a boundary between the high resistivity powder for forming the low conductive member (low conductive portion) 1 and the low resistivity powder for forming the high conductive member (high conductive portion) 2. After a layer of intermediate resistivity powder for forming the part 100 is deposited and filled, they are simultaneously compression molded.
[0082]
In this way, the intermediate resistivity powder for forming the boundary portion is filled between the low resistivity powder for forming the high conductive portion and the high resistivity powder for forming the low conductive portion. It is possible to satisfactorily suppress the occurrence of cracks and macro cracks along the boundary due to the difference in thermal expansion coefficient between the portion and the highly conductive portion.
[0083]
In a preferred embodiment of this embodiment, the composition of the intermediate resistivity powder is continuously changed from a composition similar to the composition of the low resistivity powder to a composition similar to the high resistivity powder from the low resistivity powder side to the high resistivity powder side. It may be increased manually or stepwise. For example, a plurality of intermediate resistivity powders each having a slightly different composition may be deposited little by little. In this way, since the composition of the boundary portion is changed continuously or stepwise in the thickness direction, further crack prevention can be realized.
[0084]
[Example 4]
Another embodiment of the brush of the present invention will be described below with reference to FIG.
[0085]
The brush of this embodiment may be subjected to compression molding after the molds 4 and 5 are vibrated with a vibration motor or the like for a predetermined time in the state of FIG. In this case, the low conductive powder 1 'and the high conductive powder 2' are mixed at the boundary portion, and as a result, the boundary portion becomes an intermediate resistivity powder layer. Thereafter, if compression molding is performed, cracks at the boundary can be satisfactorily suppressed.
[0086]
The technique and effect of simultaneous molding after laminating a plurality of powder layers having different compositions from each other are not limited to those in Examples 1 and 2, but a brush having a plurality of powder layers laminated with different compositions. It can be applied to all molding.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a configuration of a brush as Example 1
FIG. 2 is a set of drawings sequentially illustrating the manufacturing process of the brush as Example 1.
(A)-(f) The longitudinal cross-sectional view which shows each process typically
FIG. 3 is a set of drawings sequentially illustrating a manufacturing process of a brush in the first modified example of the first embodiment.
(A)-(d) The longitudinal cross-sectional view which shows each process typically
4 is a longitudinal sectional view showing a configuration of a brush as Example 2. FIG.
FIGS. 5A and 5B are assembly diagrams sequentially showing a manufacturing process of a brush as Example 2. FIGS.
(A)-(c) The longitudinal cross-sectional view which shows each process typically
6 is a longitudinal sectional view showing another effect of the brush of Example 1. FIG.
FIG. 7 is a longitudinal sectional view showing the structure of a brush according to the conventional technology.
FIG. 8 is a longitudinal sectional view showing the structure of a brush improved from the conventional technology.
[Explanation of symbols]
10: Brush body 11: Sliding contact surface 12: Base end surface
1: Low conductive material
2: Highly conductive material
21: Surface portion (joined with a low conductive member)
22: Surface portion (forms the surface opposite the sliding contact surface)
1 ': Low conductive powder
2 ': Highly conductive powder
21 ': surface (the lower part of the surface)
22 ': surface (the higher part of the surface)
3: Lead wire (Pigtail)
4: Female mold 40: Concave portion 41: Movable piece
5: Male

Claims (1)

It has a high conductivity member and a low conductivity member joined to the high conductivity member, and a sliding contact surface that is in sliding contact with the commutator is formed by the end surfaces of both the high conductivity member and the low conductivity member. a brush body, have a lead wire one end of which is embedded in the brush body of this, the low-conductivity member, the surface portion of the sliding surface side of the side surface of the thin plate and is and the highly conductive member is joined to the lead wire, with the sliding contact surface and the opposite becomes buried in the surface portion the low-conductivity member is not connected brush manufacturing method of the aspect of the high conductive member There,
After filling the surface of the female mold with high-conductivity powder with a step of a predetermined height and filling the lower part of the surface of the high-conductivity powder with low-conductivity powder in a roughly plate shape, A method of manufacturing a brush, comprising: pressing and solidifying and sintering the brush body.

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