WO2004054073A1

WO2004054073A1 - Method of manufacturing segment for flat commutator

Info

Publication number: WO2004054073A1
Application number: PCT/JP2003/015424
Authority: WO
Inventors: Shuji Uehara; Hideyuki Minami; Kazuo Iwashita; Hideki Horiuchi; Minoru Isoda; Yasuhiro Takebe; Yoshinori Kojima; Takayuki Ishizeki; Mitsuru Shishido
Original assignee: Mitsuba Corporation
Priority date: 2002-12-10
Filing date: 2003-12-02
Publication date: 2004-06-24
Also published as: AU2003284535A1; EP1575149A4; JP4252795B2; CN1723598A; JP2004194396A; CN100342624C; EP1575149A1

Abstract

A method of manufacturing a segment (3) for a flat commutator, comprising the steps of forming a theta section bar (15) having the same cross sectional shape as that of the segment (3) by drawing, punching out the theta section bar (15) in a direction Z perpendicular to a drawing direction X to form the segment (3) for the flat commutator, wherein the drawing direction X for the theta section bar (15) is aligned in the generally same direction as the slidable contact direction of a brush on the segment (3) and a draw-finished surface is formed to be used as a brush sliding surface (4) of the segment (3), and an anchor part (14) forming an extraction stopper for the segment (3) is formed on the theta section bar (15) in drawing, whereby the segment for the flat commutator capable of preventing the leakage of resin in a resin mold process can be easily manufactured at a low cost.

Description

Description Method for manufacturing flat commutator segments

Technical field

The present invention relates to a method for manufacturing a commutator for a rotating electric machine, and more particularly to a method for manufacturing a segment in a disk-type flat commutator. Background art

In recent years, motors used in electric power steering, engine starters, fuel pumps, and the like have come to use flat commutators (flat connectors) due to demands for downsizing the equipment. This flat type commutator has a disk-shaped brush sliding surface that extends in the radial direction from the rotation axis, unlike a general cylindrical commutator. A metal member called commutator metal is molded integrally with synthetic resin. Is done. After integral molding, the commutator metal is cut radially so as to be insulated from each other and separated in the circumferential direction to form a plurality of segments. Then, the brush slides on the brush sliding surface made of the commutator metal from the axial direction, and the armature current is switched.

As a method of manufacturing commutator metal in such a flat type commutator, a method of individually forming each segment for cold forging or forming a chain in an annular shape by a progressive press is adopted. Have been. However, according to these methods, there is a problem that the curved surface (R) at the bending corner becomes large due to press bending, ironing, drawing and the like. When the radius of the corner increases, the length of the brush sliding surface decreases by the radius, which is disadvantageous in securing the length of the sliding surface. Also, the R at the corner generates a component force in the direction of lifting the segment against resin pressure during resin molding. Furthermore, commutator metal is manufactured in a complex multi-step process requiring progressive presses, which increases equipment costs and increases the blank area to secure feed pilot holes, which lowers the yield.

FIG. 6 is an explanatory diagram showing the influence of the corner R at the time of resin molding. Shown in Figure 6 As described above, at the corner R, the resin supplied from the gate 51 tries to move from the corner 53 of the commutator metal 52 to the brush sliding surface 54 side. Then, the commutator metal 52 is deformed upward by the pressure, and the resin may leak to the inner diameter side of the brush sliding surface 54. When resin leakage occurs, not only is it necessary to remove the spar on the brush sliding surface 54, but also there is a step between the segments due to the burrs, and further cutting work is required to absorb the difference. For this reason, the number of steps in the process after the resin molding is increased, resulting in a problem that the cost is increased. In particular, in the case of pressed commutator metal, the metal may be deformed more than the spring pack, and measures to prevent resin leakage were required.

On the other hand, an attempt has been made to solve the above-mentioned problem by applying a method for manufacturing a segment used in an ordinary cylindrical commutator. FIG. 7 is a partial cross-sectional side view showing the configuration of the cylindrical commutator, and FIG. 8 is an explanatory diagram of a method for manufacturing the segments used in FIG. In the cylindrical commutator 55, the segment 56 is formed by appropriately cutting a rod-shaped member called a teeter bar. The theta-ta 57 is a drawn material made of copper and has a trapezoidal cross section as shown in FIG. The segment 56 is formed by punching out the taper 57 in the form shown by the broken line in the figure to have a shape used in the cylindrical commutator 55 in FIG.

Therefore, the flat commutator segment (commutator metal) manufactured from such a taper plate 57 does not have a rounded corner like a pressed product, and there is no problem with the spring pack. FIG. 9 is an explanatory view showing a state in which a segment of a flat commutator is manufactured from a teeter bar. If the segment 58 is cut out from the theta bar 57 as shown by the broken line in FIG. 9, the end of the brush sliding surface 59 will not be rounded. Therefore, even if the segment 58 is resin-molded, the resin does not flow around the brush sliding surface 59, and the number of post-processing steps can be reduced.

However, when the segment 58 is punched out of the tether bar 57 as shown in FIG. 9, the machined surface becomes the brush sliding surface 54. That is, the fracture surface becomes the brush sliding surface 54. For this reason, the surface roughness of the brush sliding surface 54 becomes large, and further cutting is required after punching. Therefore, although the man-hour after molding is reduced, the number of man-hours for manufacturing the segment increases, and effective cost reduction cannot be achieved. Also, segment 5 8 formation In this case, since the deleted portion of the tea bar 57 is relatively large, the yield is low and the production cost is disadvantageous. Furthermore, since the inside portion softer than the surface of the tether bar 57 becomes the plush sliding surface 54, there is a problem that the surface hardness is lowered, and the improvement has been desired.

SUMMARY OF THE INVENTION An object of the present invention is to manufacture a segment that can prevent resin leakage in a resin commutation step of a flat commutator easily and inexpensively, and to reduce the number of manufacturing steps of the flat commutator. Disclosure of the invention

The method for manufacturing a flat commutator segment according to the present invention includes: a holder formed into a disc shape by a synthetic resin; and a plurality of segments disposed along one circumferential surface of one end in the axial direction of the holder. A method for manufacturing the segment in the flat type commutator provided, comprising: a step of forming a base material having a portion having a cross-sectional shape similar to the cross-sectional shape of the segment by drawing, and cutting the base material. Forming the segment by using the above method.

In the present invention, since the segments are manufactured by cutting the base material having the same cross-sectional shape as the segments, for example, the segments can be formed by only one punching process on the base material, Many punching operations are not required. Therefore, there is no dimensional variation due to matching and feeding errors in each step, and the segment can be molded with high dimensional accuracy. In addition, since the processing of the base material is only punching and no feed accuracy is required, segment manufacturing equipment can be handled by general-purpose and inexpensive equipment, and it becomes possible to process segments at low cost.

In the method for manufacturing a flat commutator segment, the segment is radially arranged on one axial end surface of the holder portion, and the base material has a cross-sectional shape similar to a cross-sectional shape along a radial direction of the segment. You may have it. In the method for manufacturing a segment for a flat commutator, the direction in which the base material is drawn may be substantially the same as the direction in which the brush slides on the segment. As a result, the processing direction of the brush sliding surface substantially matches the brush sliding direction, and the drawn surface can be used directly as the brush sliding surface without cutting after punching. It becomes.

In the method of manufacturing a flat commutator segment, the drawn surface of the base material may be a brush sliding surface of the segment. As a result, the portion where the work hardening occurs in the drawing becomes the brush sliding surface, the hardness of the brush sliding surface can be improved, and the durability of the commutator can be improved.

Further, in the method for manufacturing a flat commutator segment, an anchor portion for preventing the segment from coming off in the axial direction with respect to the holder portion may be formed on the base material by the drawing process. This eliminates the need for an anchor portion forming operation such as taper processing and nail shaving processing after the drawing process, thereby reducing man-hours.

On the other hand, in the method of manufacturing a segment for a flat commutator, the segment may be formed by punching the base material in a direction perpendicular to the drawing direction. In this case, the segments may be punched out in a state where the adjacent segments have their inner and outer diameter sides inverted. As a result, unnecessary portions of the base material are reduced, segments can be punched very efficiently, segment yield can be improved, manufacturing costs can be reduced, and waste can be reduced. Become. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a partially cutaway perspective view showing an example of a flat commutator using a segment manufactured by a manufacturing method according to the present invention.

FIG. 2 is a perspective view showing a configuration of a segment of the flat commutator.

FIG. 3 is an explanatory diagram showing a segment manufacturing method according to the first embodiment of the present invention. FIG. 4 is an explanatory diagram showing a segment manufacturing method according to the first embodiment of the present invention. FIG. 5 is an explanatory diagram showing a segment manufacturing method according to the second embodiment of the present invention. FIG. 6 is an explanatory diagram showing the influence of the corner R at the time of resin molding.

FIG. 7 is a partial cross-sectional side view showing the configuration of the cylindrical commutator.

FIG. 8 is an explanatory diagram of a method of manufacturing the segment used in FIG.

Figure 9 shows how a flat commutator segment is manufactured from a teeter bar. FIG. BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment 1)

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a partially cut perspective view showing an example of a flat commutator using a segment manufactured by a manufacturing method according to the present invention.

The commutator 1 has a flat structure as shown in FIG. 1, and is used for a starter motor, an in-tank fuel supply pump, and the like. The commutator 1 includes a synthetic resin holder 2 and a plurality of metal segments 3, and the segment 3 is molded integrally with the holder 2. The surface of segment 3 (the upper surface in Fig. 1) is a brush sliding surface 4, where a brush (not shown) comes into contact from the axial direction.

Such a commutator 1 is formed by mounting the individual segments 3 on a circular cartridge, and then molding the whole with synthetic resin in that state. The molded commutator 1 is assembled together with a rotating shaft armature core and a coil winding (not shown), and then coated with a synthetic resin to form an armature assembly.

The holder part 2 is formed in a thick, substantially disk shape, and a shaft hole 5 for fixing a motor rotation shaft is formed in a center part. A plurality of segments 3 are arranged at equal intervals on one axial end surface of the holder 2. Each segment 3 is formed in a substantially sector shape, and is radially arranged on the surface of the holder 2. Slits 6 are formed between the segments 3 to electrically insulate the adjacent segments 3 from each other. FIG. 2 is a perspective view showing the configuration of the segment 3. As shown in FIG. 2, the segment 3 has a main body portion 7 on which the brush sliding surface 4 is formed, and an outer peripheral portion 8 formed with a step outside the main body portion 7. An outer peripheral portion 8 is provided with a U-shaped coil mounting groove 9. An armature coil (not shown) is fixed to the coil mounting groove 9 by fusing or the like.

A boss 11 is provided on the inner peripheral side of the main body 7, and a taper 1 2a is formed. The boundary between the main body 7 and the outer peripheral portion 8 is a stepped portion 13, and the inner surface side is also a tapered portion 12 b. The tapered portions 12 a and 12 b are expanded toward the main body 7 side, and form an anchor portion 14 which serves as an axial stopper for the segment 3 with respect to the holder portion 2.

Such a segment 3 is formed as follows. 3 and 4 are explanatory diagrams showing a method for manufacturing the segment 3 according to the first embodiment of the present invention. As shown in Figure 3, segment 3 is also cut from a copper tether bar (base metal). The theta bar 15 is formed by drawing a copper material in the direction indicated by the arrow X. The cross section is the same as the A-A cross section (radial cross section) in Fig. 2 of the segment 3 as shown in Figs. It is molded into. That is, the tether bar 15 has a form in which a main body forming part 17 that becomes the main body part 7, an outer peripheral forming part 18 that becomes the outer peripheral part 8, and a boss forming part 21 that becomes the boss part 11 are formed into a body. Has become.

A stepped portion 23 is formed between the main body forming portion ₁₇ and the outer peripheral forming portion 18 of the tether bar 15, and tapered surfaces 22 a and 22 b are respectively formed inside them. Since the cross-sectional shape of the theta bar 15 is determined by the drawing die, the degree of freedom of the cross-sectional shape is greater than that of the bending process, and the inside of the boss 11 and the inside of the step 23 are also easily tapered 2 a , 2 2 b. In the case of the commutator metal 52 formed by pressing, as shown in Fig. 6, a process of forming the boss portion 61 into a tapered shape and a nail shaving process of forming the engaging piece 62 are required as shown in FIG. . On the other hand, in the segment 3, the anchor shape is formed at the same time in the drawing process, so that taper processing, nail shaving processing, and the like become unnecessary, thereby reducing man-hours.

Segment 3 is stamped side-by-side from the tether bar 15, as shown in Figure 4. Punching is performed in a direction perpendicular to the drawing direction X (Y direction in Fig. 3). Segment molding from the data bar 15 can be performed by a single punching process.Compared to multiple punching, there is no dimensional variation due to matching and feeding errors in each process, and segment 3 can be formed with high dimensional accuracy. Can be molded. The equipment used at that time also requires only punching and does not require feed accuracy, so general-purpose and inexpensive equipment can be used, and segment 3 can be processed at low cost.

Also, as shown in Fig. 4, the punching of segment 3 The area to be deleted can be reduced. Therefore, the material is effectively used and the yield is improved. Furthermore, there is no bending in the molding of segment 3 and the radius of the corner is minimized. Therefore, the resin does not flow around the brush sliding surface 4 due to the resin mold, and the number of post-processing steps can be reduced.

On the other hand, in segment 3, the brush sliding surface 4 is the outer surface 17a of the main body forming portion 17. That is, the drawn surface becomes the brush sliding surface 4. The drawing surface] has higher surface roughness and flatness than the fractured surface by punching, and can be used as the brush sliding surface 4 as it is. In the conventional segments shown in Figs. 8 and 9, the drawing surface is buried in the resin mold, and the fracture surface is the brush sliding surface 4, which is not used despite its good surface. In contrast, in segment 3, the drawing surface is set to be the brush sliding surface 4, and the good surface is actively used. Therefore, if the segment 3 is used, the finishing of the brush sliding surface 4 after the resin molding becomes unnecessary, and the man-hour for manufacturing the commutator 1 can be reduced. The outer surface 17a of the body forming portion 17 has a higher hardness due to work hardening by drawing, and the durability of the brush sliding surface 4 is also improved.

Generally, the withdrawal direction X of the tether bar is perpendicular to the brush sliding direction (rotation direction) Z, as shown in FIGS. In view of the orientation of the material on the surface of the brush sliding surface 4, it is preferable that the processing direction and the brush sliding direction match. However, in the case of Figs. 8 and 9, the brush sliding surface of the segment is scheduled to be cut and finished after punching, so there is not much effect even if the directions of both are different. On the other hand, on the brush driving surface 4 of the segment 3, the pulling direction (the X direction in FIG. 3) of the theta bar 15 is substantially the same as the force brush sliding direction (the Z direction in FIG. 2). In this embodiment, the tangential direction of the brush sliding direction Z on the circumferential center line (the line A_A in FIG. 2) of the segment 3 matches the drawing direction X of the thetaper 15. Therefore, in segment 3, post-machining caused by the difference between the machining direction and the brush sliding direction can be omitted, and due to the goodness of the drawn surface and the surface hardness, punching of the data bar 15 is performed. Can be commercialized as it is.

(Embodiment 2) ''

FIG. 5 is an explanatory diagram showing a segment manufacturing method according to the second embodiment of the present invention. The same parts and members as in Embodiment 1 are given the same reference numerals, and description thereof is omitted.

In the manufacturing method according to the second embodiment, so-called staggered cutting is performed on the tether bar (base material) 25 as shown in FIG. 5 in order to further increase the yield of the segment 3. The theta-taper 25 has a portion having the same cross-sectional shape as that of the segment 3 so as to penetrate the adjacent segment 3 in the vertically opposite direction, and has a vertically symmetrical form. That is, the outer peripheral portion 18 of the theta bar 15 having the same cross-sectional shape as the segment 3 is provided at both ends, and the outer end portion 26 is formed at both ends. .

The adjacent segment 3 is punched up and down, that is, with the inside diameter side and the outside diameter side reversed. The outer end 26 of the theta bar 25 on the inner diameter side (tapered side) is punched at an intermediate position to form a boss 11. As is clear from comparison of FIGS. 4 and 5, the unnecessary portion of the tether bar 25 is small in this manufacturing method, and the segment 3 is punched out very efficiently. Therefore, the yield of segment 3 can be improved, and not only can the manufacturing cost be reduced, but also the amount of waste can be reduced.

The present invention is not limited to the above embodiment, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

For example, in the commutator 1 described above, it is possible to omit the cutting finish for cleaning the brush sliding surface 4, but the flatness and surface roughness may be appropriately reduced by cutting according to the required accuracy of the finished product. Finishing may be performed. Therefore, the theta bars 15 and 25 may have not only the same cross-sectional shape as the segment 3 but also a shape that can be easily formed into the segment 3 by post-processing. Not including cross-sectional shapes. In the case of performing post-processing, the number of steps such as grinding can be reduced as compared with the conventional case.

According to the method for manufacturing a flat commutator segment of the present invention, a base material having a section having the same cross-sectional shape as that of the segment is formed by drawing, and the base material is cut to form a segment. In this way, the segment can be formed by cutting the base material, eliminating the need for multi-step processing. Therefore, there is no variation in dimensions due to matching of each process or a feeding error, and a segment can be molded with high dimensional accuracy. In addition, since feed precision is not required for the processing of the base material, segment manufacturing equipment can be handled by general-purpose and inexpensive equipment, and it becomes possible to process segments at low cost. In addition, by setting the drawing direction of the base material to be substantially the same as the brush sliding direction of the segment, the processing direction of the brush sliding surface can be substantially matched with the brush sliding direction. The drawing surface can be used as it is as the brush sliding surface without performing.

Furthermore, by using the brushed surface of the base material as the brush sliding surface of the segment, the portion where work hardening occurs during the drawing becomes the brush sliding surface, and the hardness of the brush sliding surface can be improved. The durability of the commutator is improved.

In addition, by forming the anchor portion on the base material by drawing, the anchor portion forming work such as tapering and nail shaving after the drawing process is not required, thereby reducing man-hours.

On the other hand, by punching out the base metal in a state where the inner and outer diameters of the adjoining segments are inverted with each other, unnecessary portions of the base metal can be reduced, and the segments can be punched efficiently, thereby improving the segment yield. Not only can manufacturing costs be reduced, but also waste can be reduced.

Claims

The scope of the claims

1. A flat type commutator having a disk-shaped holder made of a synthetic resin and a plurality of segments disposed along one end face of the holder in the axial direction along the circumferential direction. A manufacturing method,

Forming a base material having a site having a cross-sectional shape similar to the cross-sectional shape of the segment by drawing;

Cutting the base material to form the segments. A method for manufacturing a flat commutator segment, comprising the steps of:

2. The method for manufacturing a flat commutator segment according to claim 1, wherein the segments are radially arranged on one axial end surface of the holder portion, and the base material has a cross-sectional shape along a radial direction of the segments. A method of manufacturing a segment for a flat commutator, comprising a portion having a similar cross-sectional shape.

3. The method for manufacturing a flat commutator segment according to claim 1 or 2, wherein a drawing direction of the base material is substantially the same as a brush sliding direction of the segment. Manufacturing method.

4. The method for manufacturing a flat commutator segment according to any one of claims 1 to 3 p, wherein the drawing surface of the base material is a brush sliding surface of the segment. Manufacturing method of segment for automobile.

5. The method for manufacturing a flat commutator segment according to any one of claims 1 to 4, wherein the anchor portion serving as an axial stopper for the segment with respect to the holder portion is formed by the drawing process. A method for manufacturing a flat commutator segment, wherein the segment is formed in a material.

6. The method for manufacturing a flat commutator segment according to any one of claims 1 to 5, wherein the segment is formed by punching the base material in a direction perpendicular to a drawing direction thereof. Manufacturing method for flat commutator segments.

7. The method for manufacturing a flat commutator segment according to claim 6, wherein the segments are formed such that adjacent segments have their inner diameter side and outer diameter side inverted with respect to each other. A method for manufacturing a flat commutator segment, characterized by being punched out in a state.