JP3560197B2 - Method and apparatus for manufacturing sliding brush for electric machine - Google Patents

Description

【００２９】
以上の結果から明らかなように、ダイスの表面における荒らし面は、中心線平均表面粗さＲ_ａ が３μｍよりも粗く形成されている場合に、初期ノイズの低減効果が発揮される。
特に、ブラシ摺動面表面粗さＲ_ａ が１０μｍよりも粗く形成されている場合に、初期ノイズの低減効果が有効に発揮される。
尚、上記実施の形態では、上型により材料粉末を圧搾成形する場合について説明したが、特にこれに限定されることはなく、基板に対して水平に摺動する圧搾手段を用いて圧搾成形しても良い。
【００３０】
【発明の効果】
以上の説明で明らかなとおり、本発明の摺動ブラシの製造方法およびその装置によれば、圧搾室内において成形されたブラシ成形体は、ロアパンチの作用により圧搾室から押し出される際に、ブラシ摺動面が硬質砥粒の電着またはブラストによる荒らし加工が施されたダイス表面によって荒らされる。
これにより金型成形時の圧搾作用により緻密化され、表面が固化されたブラシ摺動面の表面層は除去される。
よって、従来のようにブラシ摺動面に特別な後加工を施す必要性もなくなり、電動機等の整流作用において初期ノイズの少ない特性を有する摺動ブラシを連続的に得ることができる。
【図面の簡単な説明】
【図１】本発明に係る摺動ブラシの製造装置の一実施例を一部破断して示した正面図である。
【図２】図１に示す実施例を一部破断して示した側面図である。
【図３】図２におけるＩＩＩ−ＩＩＩ線を矢印方向に見た断面図である。
【図４】図１に示す実施例の主要部を示した斜視図である。
【図５】圧搾室部分の構成を示した断面図である。
【図６】圧搾室より摺動ブラシを押し出す過程を示した断面図である。
【符号の説明】
１ 基台
２ 圧搾室
３ 上型
４ フィーダー
５ ホッパー
７ ロアパンチ
８ 摺動ブラシ
８ａ ブラシ摺動面
９ 導線
１０ 切断器
１１ 押型
１１ｂ ダイス
ａ 材料粉末[0001]
[Industrial applications]
The present invention relates to a method and an apparatus for manufacturing a sliding brush for an electric machine used for, for example, an electric motor, and more particularly to a manufacturing method and an apparatus for manufacturing a sliding brush capable of reducing the generation of initial noise. Things.
[0002]
[Prior art]
In general, rectifying sliding brushes are used in electric machines such as electric motors and generators, and many of them use metallic graphite sliding brushes.
The metallic graphite sliding brush used in these electric machines is formed by compressing a material powder such as graphite or copper filled in a molding die and baking it, for example.
It is known that the sliding brush formed in this manner causes a phenomenon in which the material powder on the mold wall surface is stretched and densified by the squeezing action at the time of molding, and the surface is solidified.
Further, for example, copper content is molded at 30 wt% to 60 wt%, the centerline average surface roughness _{R a} of the sliding brush sliding surface firing was made was about 0.5Myuemu～1.5Myuemu.
[0003]
For this reason, when used as it is for a sliding brush of an electric motor or the like, there is a technical problem that the brush sliding surface having a solidified surface directly hits a commutator of the electric motor or the like, and the initial noise is high.
In addition, there is a technical problem of causing a failure to other electric devices and the like.
Therefore, devising the softening of the base material by adjusting the binder mixed with the material powder or the molding pressure, or applying an appropriate taper, arc or wavy shape to the sliding surface of the formed brush Measures have been taken to reduce the initial noise by processing.
[0004]
[Problems to be solved by the invention]
However, in the case where a device such as adjusting the binder and the molding pressure is applied as described above, a new problem occurs that the abrasion resistance of the brush deteriorates.
In addition, when performing post-processing such as taper, arc or corrugation on the sliding surface of the brush formed in a mold, processing equipment such as a grinder is required, and some skill is required for processing. It becomes.
Further, there is a problem that cost increase due to an increase in the number of manufacturing steps is unavoidable.
[0005]
The present invention has been made to solve the above-described technical problem, and at the time of mold release for squeezing material powder to form a brush body, simultaneously removing a surface layer of a brush sliding surface. by configured to be, shaped, the center line average surface roughness R _a of the sliding brush surface after sintering was 2 to 15 [mu] m, the manufacturing method of the sliding brush that can reduce the occurrence of initial noise and It is intended to provide such a device.
[0006]
[Means for Solving the Problems]
A method for manufacturing a sliding brush according to the present invention made to achieve the above object includes a step of filling a material powder for forming a sliding brush into a pressing chamber, and pressing the material powder in the pressing chamber to obtain a material powder. Forming a predetermined shape, and extruding the brush molded body formed by the pressing from the compression chamber and roughening the brush sliding surface of the brush molded body to remove the surface layer of the brush sliding surface. It is characterized by having.
[0007]
Further, the sliding brush manufacturing apparatus according to the present invention includes a base having a pressing chamber for forming a sliding brush, a feeder for supplying material powder into the pressing chamber of the base, and a material powder in the pressing chamber. Squeezing molding means for squeezing, a lower punch for extruding the sliding brush after the squeezing in the squeezing chamber, and a brush sliding surface of the squeezed sliding brush provided on a path extruded by the lower punch. And a die for removing a surface layer of the brush sliding surface.
[0008]
In this case, the surface of the die from which the surface layer of the brush sliding surface is removed is preferably subjected to roughening by electrodeposition or blasting of hard abrasive grains, and further, the roughened surface on the surface of the die has a center line average. It is desirable that the surface roughness _Ra is formed to be larger than 3 μm.
Further, it is preferable that _Ra is formed coarser than 10 μm.
[0009]
[Action]
According to the manufacturing method of the sliding brush described above, the brush molded body molded in the compression chamber is roughened when the brush molded body is extruded from the compression chamber, and the squeezing action at the time of mold molding is performed. The surface layer of the brush sliding surface which has been densified and whose surface has been solidified is removed.
Further, according to the above-described apparatus for manufacturing a sliding brush, a die is formed following the pressing chamber, and the surface of the die is roughened by, for example, electrodeposition of hard abrasive grains or blasting.
By extruding the sliding brush after the completion of the compression molding by the lower punch, the surface layer of the brush sliding surface is roughened and the surface layer is removed.
Therefore, the surface layer of the brush sliding surface whose surface has been solidified in the releasing step following the pressing is removed.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail based on the embodiment shown in FIGS. A reference numeral 1 shown in the figure is a base having a compression chamber 2 for forming a sliding brush at a substantially central portion thereof. Above the base 1, an upper opening of the compression chamber 2 is openably and closably closed. An upper die 3 for squeezing material powder a, which will be described later, is provided.
Further, a feeder 4 for feeding the material powder a into the compression chamber 2 and a hopper 5 for supplying the material powder a to the feeder 4 are arranged on the upper surface of the base 1.
[0011]
In addition, a lower punch 7 for extruding the semi-finished product (sliding brush) A after the completion of the compression molding is provided on the lower surface of the compression chamber 2.
Further, one end of a conductive wire 9 attached to a sliding brush 8 is inserted through the upper die 3, and the upper die 3 is pressed by the upper die 3 on the upper surface of the base 1, that is, at a position facing the feeder 4. A cutting device 10 for cutting the conductive wire 9 having one end embedded in a molded sliding brush 8 to a predetermined length is arranged.
[0012]
The above is the overall configuration of the embodiment of the sliding brush manufacturing apparatus according to the present invention. Next, each part of the apparatus configured as described above will be described in detail.
The squeezing chamber 2 includes a pressing die 11 provided at an upper portion in a stepped hole 1a provided in the base 1, and the upper die 3 sliding in a notch groove 11a of the pressing die 11.
The pressing die 11 is integrally fixed to the base 1 via a pressing die 12 fitted on the outer wall of the pressing die 11.
[0013]
The upper die 3 is provided with conductive rod insertion holes 14b formed in the axial direction from the side of the operating rod 14a of the operating device 14 provided at the upper end of the four columns 13 supporting the base 1. A through-hole 3a is formed at a right angle to the above, so that one end of the conducting wire 9 wound around the reel 15 at the other end is inserted therethrough.
[0014]
The feeder 4 is a rectangular box body having an opening at the lower surface and a material inlet 6 at the center of the upper surface. The lower end surface of the feeder 4 is slidably contacted with the upper surface of the base 1 by the operating rod 16a of the operating device 16. It reciprocates toward the squeezing chamber 2.
An openable / closable shutter 17 is mounted between the upper end side wall of the feeder 4 and the material supply port 5a of the hopper 5.
[0015]
The lower punch 7 is attached to the upper end surface of an operating rod 19 of an operating device 18 which protrudes upward through a stepped hole 1a provided on the lower surface of the base 1, and pushes out the product after compression molding upward. It is configured to be able to.
As shown in FIG. 3, the cutting device 10 of the conducting wire 9 is rotatably supported via a support shaft 21 having a lower end screwed into a substrate 20 projecting from the upper surface of the base 1, and has a free end. Is provided with a lever 23 having a cutting blade 22 composed of a fixed blade 22a and a movable blade 22b. A movable lever 24 slidable in the axial direction is attached to one side wall of the lever 23 via a support screw (not shown).
[0016]
On the upper surface of one end of the movable lever 24, a locking pin 27 that engages with an engagement groove 26 provided at a position spaced from the pivot 25 of the movable blade 22b, and on the lower surface of the other end. Are provided with pins (not shown) that come into contact with stoppers (not shown) protruding from the upper surface of the substrate 20 when the lever 23 is rotationally displaced.
Further, an auxiliary lever 28 is mounted on the fulcrum of the lever 23, that is, on the upper surface of the pivotal connection with the support shaft 21 at a predetermined angle with respect to the axis of the lever 23. The end is connected to the tip of the operating rod 30 in the cutter cylinder 29 as shown in FIG.
[0017]
When the lever 23 rotates clockwise and the pin comes into contact with the stopper, the movable lever 24 slides, and the movable blade 22 b rotates via the pivot 25.
At this time, the conductive wire 9 interposed between the fixed blade 22a and the movable blade 22b is cut.
[0018]
Reference numeral 31 in the drawing denotes a detecting section of a control device (not shown) for controlling the operating range of each of the operating rods 14a, 16a, 19, 30. 31a and a switch 31b.
[0019]
FIG. 5 is an enlarged sectional view showing details of the pressing chamber 2 formed in the notch groove 11a of the pressing die 11 and the die 11b following the pressing chamber 2.
The pressing chamber 2 is configured so that four sides are surrounded by the pressing dies 11 existing in the front, rear, left and right directions in FIG. 5, and a sealed space is formed by the upper die 3 and the lower punch 7 existing above and below.
A die 11b is formed in an upper part following the compression chamber 2. The die 11b is formed in a part of the notch groove 11a in the pressing die 11, and the surface thereof is subjected to electrodeposition of hard abrasive grains or roughening by blasting.
The roughened surface is extended outward with a small dimension d (d = 0.002 to 0.2 mm) with respect to the side wall of the compression chamber 2.
The length of the die 11b is preferably set to a length corresponding to 1/2 to 1 of the thickness of the compact after pressing in order to reliably remove the surface layer of the brush sliding surface.
[0020]
Next, the operation of the sliding brush manufacturing apparatus configured as described above will be described. First, the operating rod 16a of the operating device 16 is slid to the predetermined position from the state in which the operating rods 14a, 16a, 19, and 30 are retracted to the predetermined positions (the states shown in FIGS. 1 to 3). The powder material a is supplied into the compression chamber 2.
At this time, the material supply port 5a of the hopper 5 is closed on the upper surface of the shutter 17.
[0021]
Next, by returning the feeder 4 to the original position, the material powder in the hopper 5 is supplied into the feeder 4, and the upper die 3 is lowered as shown in FIG. Then, the material powder a is pressed and molded.
At this time, one end of the conductive wire 9 extending from the lower end surface of the upper die 3 is in a state of protruding into the compression chamber 2, so that one end of the conductive wire 9 is embedded in the sliding brush 8 formed by compression.
[0022]
Next, the upper die 3 is retracted to the original position. At this time, since the sliding brush 8 is pressed against the wall surface of the squeezing chamber 2 at the same time, the conducting wire 9 is extended by a predetermined length.
Then, by projecting the operating rod 30 of the cutter 10 by a predetermined length, the conductive wire 9 is interposed between the fixed blade 22a and the movable blade 22b, and the conductive wire 9 is cut to a predetermined length.
[0023]
Next, the cutter 10 is retracted, and simultaneously the lower punch 7 is raised.
Here, as the lower punch 7 is raised, the sliding brush 8 is pushed out of the pressing chamber 2 through the die 11b to the upper part of the die 11 in the order shown in FIGS. 6A, 6B, and 6C.
That is, the sliding brush 8 is pushed up from the inside of the compression chamber 2 shown in FIG. 6A by the raising of the lower punch 7 as shown in FIG. 6B, and the sliding brush 8 is slightly expanded by a so-called spring back action. The brush sliding surface 8a of the sliding brush 8 comes into contact with a roughened die 11b.
[0024]
Then, the lower punch 7 continues to ascend, and pushes the sliding brush A to the upper part of the pressing die 11 as shown in FIG.
At this time, the brush sliding surface 8 of the sliding brush 8 is roughened by the roughened surface of the die 11b, and the surface layer of the brush sliding surface is removed.
That is, the surface layer of the brush sliding surface, which has been densified by the pressing action at the time of molding and has a solidified surface, is removed.
[0025]
In this way, the sliding brush 8 is pushed out to the upper part of the pressing die 11, and when the feeder 4 subsequently slides and the lower punch 7 retreats, the material powder a is again supplied into the pressing chamber 2.
At this time, the sliding brush 8 is simultaneously transferred to a predetermined position in the horizontal direction by the side wall of the feeder 4.
Subsequently, by repeating the same operation as described above, it is possible to continuously obtain a metal-graphite molded body with a conductive wire.
Then, if the formed body is fired in a firing furnace (not shown), a metal graphite sliding brush having _a center line average surface roughness Ra of the sliding surface of 2 to 15 μm can be easily manufactured. The present invention is an optimal method particularly for producing a metallic graphite sliding brush having a metal (e.g., copper, silver) content of 30 to 60% by weight.
[0026]
As described above, according to the sliding brush obtained by the method and the apparatus according to the present invention, when the sliding brush 8 is released from the pressing chamber 2, the brush sliding whose surface is solidified by the pressing action is solidified. The surface layer of the surface is removed at the same time.
Therefore, even if it is used as it is for a sliding brush of an electric motor or the like, characteristics with little initial noise in the rectifying action can be obtained.
[0027]
Next, a description will be given of an experimental result on the optimum roughness of the roughened surface of the die 11b.
First, copper 38 wt%, graphite 58 wt%, the M O _S 2 ₄ consisting wt% material, an appropriate amount of phenol - alcohol was dissolved Le resin - mixed le, kneaded, and dried, and pulverized, molded I do.
Then, at the time of molding, _a roughened surface on the surface of the die was made rougher than _Ra = 3 μm, and a brush molded body having _a brush sliding surface surface roughness _{Ra of 2} , 6, 11, 15 μm was prepared and fired. (Examples 1 to 4).
Also, as a comparative example, after molding with a material of the same quality as the above example, the roughened surface of the die was set to a surface smaller than _Ra = 3 μm, and the brush sliding surface surface roughness _Ra was set to 0.1 μm. A brush molding was prepared and fired.
These were assembled in a motor for an automobile wiper, and the initial noise was measured.
Table 1 below shows the center line average surface roughness of each brush sliding surface after firing, and the results of measuring the initial noise by incorporating them into a motor for an automobile wiper.
[0028]
[Table 1]

[0029]
As is clear from the above results, the roughened surface of the die has an effect of reducing the initial noise when the center line average surface roughness _Ra is formed to be larger than 3 μm.
In particular, the brush sliding surface roughness R _a is in the case which is rougher than the 10 [mu] m, the effect of reducing the initial noise is effectively exhibited.
In the above-described embodiment, the case where the material powder is pressed by the upper mold is described.However, the present invention is not particularly limited to this, and the pressing is performed by using a pressing means that slides horizontally on the substrate. May be.
[0030]
【The invention's effect】
As apparent from the above description, according to the method and the apparatus for manufacturing the sliding brush of the present invention, when the brush molded body formed in the compression chamber is pushed out of the compression chamber by the action of the lower punch, the brush slides. The surface is roughened by the die surface which has been roughened by electrodeposition or blasting of hard abrasive grains.
As a result, the surface layer of the brush sliding surface, which is densified by the squeezing action at the time of molding and has a solidified surface, is removed.
Therefore, there is no need to perform special post-processing on the brush sliding surface as in the related art, and it is possible to continuously obtain a sliding brush having low initial noise characteristics in a rectifying action of an electric motor or the like.
[Brief description of the drawings]
FIG. 1 is a partially cutaway front view showing an embodiment of a sliding brush manufacturing apparatus according to the present invention.
FIG. 2 is a side view of the embodiment shown in FIG.
FIG. 3 is a sectional view taken along line III-III in FIG. 2 in the direction of the arrow.
FIG. 4 is a perspective view showing a main part of the embodiment shown in FIG. 1;
FIG. 5 is a cross-sectional view showing a configuration of a squeezing chamber portion.
FIG. 6 is a cross-sectional view showing a process of pushing out a sliding brush from a squeezing chamber.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Base 2 Squeezing room 3 Upper die 4 Feeder 5 Hopper 7 Lower punch 8 Sliding brush 8a Brush sliding surface 9 Conductor 10 Cutting device 11 Pressing die 11b Dice a Material powder

Claims (4)

A step of filling a material powder for forming a sliding brush into a compression chamber, a step of compressing the material powder in the compression chamber to form the material powder into a predetermined shape, and forming the brush molded body formed by the compression Extruding the brush from the pressing chamber and roughening the brush sliding surface of the brush formed body to remove the surface layer of the brush sliding surface. A base having a squeezing chamber for sliding brush molding, a feeder for supplying material powder into the squeezing chamber of the base, squeezing means for squeezing the material powder in the squeezing chamber, and squeezing in the squeezing chamber. A lower punch for extruding the sliding brush after the completion, and a die provided on a path extruded by the lower punch, for roughening the brush sliding surface of the compression-formed sliding brush and removing a surface layer of the brush sliding surface. An apparatus for manufacturing a sliding brush for an electric machine, comprising: The sliding brush for an electric machine according to claim 2, wherein the surface of the die from which the surface layer of the brush sliding surface is removed has been subjected to electrodeposition of hard abrasive grains or roughening by sandblasting. Manufacturing equipment. 3. A roughened surface on a surface of a die which has been subjected to roughening processing by electrodeposition or blasting of the hard abrasive grains, is formed so that _a center line average surface roughness _Ra is larger than 3 μm. An apparatus for manufacturing a sliding brush for an electric machine according to claim 3.

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