JP3697357B2 - Commutator unit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a commutator unit attached to a rotating electric machine such as a small motor.
[0002]
[Prior art]
Small motors are widely used in various fields such as audio / video equipment and optical precision equipment, and in recent years, light weight, thinning, and high performance are progressing. In the small motor, a permanent magnet is mounted inside a casing, and a rotor that is rotatably supported by a bearing is disposed to face the permanent magnet. The rotor is provided with a commutator unit having a commutator piece, and a brush installed in the casing is in sliding contact with the commutator unit to supply power to the rotor armature winding.
[0003]
There are two types of commutator units: a mold type that integrates the whole with a thermosetting resin and an assembly type that uses a thermoplastic resin for the insulating part, but it has relatively little current and heat generation. Assembling type commutator units are often used for small motors.
[0004]
FIG. 6 is an exploded perspective view showing a conventional assembly type commutator unit, and FIG. 7 is a partial cross-sectional view showing a cross section of a part thereof. This commutator unit includes an insulating base 10 in which a flange portion 12 is formed at one end of a cylindrical portion 11, three commutator pieces 20 made of a conductive metal attached to the insulating base 10, and a commutator piece 20. And an insulating washer 30 that presses the commutator piece 20 against the outer peripheral surface of the insulating base 10 and fixes them together. The commutator piece 20 has a commutator portion 21 that is curved in an arc shape and is in sliding contact with the brush 40, and a riser portion 22 that is radially provided from one end side of the commutator portion 21. An end portion of an armature winding (not shown) is connected to the riser portion 22. In such a structure, the means for fixing the plurality of commutator pieces 20 to the outer peripheral surface of the insulating base 10 depends on the pressing force of the insulating washer 30.
[0005]
A slit 23 having a predetermined width S is provided between adjacent commutator pieces 20 and plays an important role in determining the switching timing of energization to the armature winding. Therefore, when the width S of the slit 23 is not uniform, the rotational characteristics of the motor are adversely affected. Therefore, in the insulating base 10 shown in FIG. 6, the positioning groove 13 is provided in the flange portion 12, and the commutator piece 20 is positioned by engaging the riser portion 22 with the positioning groove 13.
[0006]
Further, the slit 23 needs to ensure that the adjacent commutator pieces 20 are insulated from each other in order to maintain the rotation of the motor. However, if the commutator piece 20 and the brush 40 slide over a long period of time, the wear powder accumulates in the slit 23, and there is a possibility that the commutator pieces 20 are short-circuited. Therefore, in the conventional assembly type commutator unit, the concave groove 19 is provided at a position corresponding to the slit 23 on the outer peripheral surface of the cylindrical portion 11 of the insulating base 10, and wear powder is accumulated in the concave groove 19 to commutate the commutator. A means for avoiding a short circuit between the pieces 20 has been adopted.
[0007]
[Problems to be solved by the invention]
However, when the concave groove 19 is provided at a position corresponding to the slit 23, the width S cannot be uniformly regulated by directly using the slit 23. Therefore, when the commutator unit is incorporated in the motor or the riser unit 22 When the armature windings are soldered to each other, the upper end portion of each commutator piece 20 may fall to the left and right, and the width S of the slit 23 may become uneven. In particular, in the case of a motor that increases energization switching efficiency and increases torque, the number of commutator pieces 20 is increased, so that the open angle of the arc of each commutator piece 20 is reduced. For this reason, the contact area with the insulating base 10 is reduced, the upper end portion of the commutator piece is more likely to collapse, and the width S of the slit 23 becomes non-uniform. As a result, the roundness of the commutator unit deteriorates, and there is a problem in that the rotational characteristics of the motor are adversely affected.
[0008]
In addition, when the insulating washer 30 is fitted on the outer periphery of the commutator piece 20 and the commutator piece 20 and the insulating base 10 are closely fixed, as shown in FIG. 7, the inner peripheral surface of the insulating washer 30 and the cylindrical portion 11 A gap G having only one opening is generated between the two. And the abrasion powder which arises when the commutator piece 20 and the brush 40 slide is gradually accumulate | stored in this space | gap part G, and there also exists a problem that commutator pieces 20 will short-circuit with an abrasion powder eventually. .
[0009]
In view of the actual situation as described above, the present invention provides a commutator unit that can prevent the commutator pieces from collapsing and uniformize the width of the slits, and can ensure insulation between adjacent commutator pieces. It is to provide.
[0010]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention according to claim 1 of the present invention is characterized in that a plurality of commutator pieces having a commutator portion formed in an arc shape and a riser portion connected to the commutator portion are formed in a cylindrical shape. A slit is provided between the commutator pieces on the outer peripheral surface of the insulating base, and a ring-shaped washer is fitted to the outer periphery on the riser side to fix the commutator piece to the insulating base. In this commutator unit, the insulating base is characterized in that a discharge passage communicating from the slit to the outer peripheral side of the insulating base is formed.
[0011]
The present invention, since the form discharge passage communicating from each provided with slits into a plurality of commutator segments on an outer circumferential side of the insulating substrate, without abrasion powder is accumulated in the or gap portion a slit, the discharge passage It is discharged to the outer peripheral side of the commutator unit. As a result, insulation between adjacent commutator pieces can be reliably achieved.
[0012]
The invention according to claim 2, in claim 1, the base end side of the insulating substrate, a flange portion for mounting the washer is provided, the opening of the plurality of discharge passage communicating with the slits on the outer periphery of the flange portion Each is formed.
[0013]
According to such a configuration, it is possible to prevent wear powder from being discharged outward from the outer peripheral side of the flange portion on the side opposite to the slide contact where the commutator piece and the brush are in sliding contact, and the wear powder reaching the slide contact. Insulation between the commutator pieces can be ensured.
[0014]
The invention according to claim 3 is the invention according to claim 1, wherein the cylindrical outer peripheral surface of the insulating base is formed with a bulge-shaped convex portion lower than the outer peripheral surface of the commutator portion at a position corresponding to each slit, A discharge passage is formed which communicates from the gap between the outer peripheral surface of the convex portion and the inner peripheral surface of the washer to the outer peripheral side of the insulating base.
[0015]
According to such a configuration, since the protruding portion having a jetty shape lower than the outer peripheral surface of the commutator piece is formed to bulge in the cylindrical portion, in addition to the above effect, the width of the slit between adjacent commutator pieces is protruded. In addition to being able to be uniformly regulated by the portion, when the washer is inserted, only the commutator piece can be pressed without the inner peripheral surface of the washer contacting the convex portion, and the adhesion between the commutator piece and the insulating base can be improved. . Further, the wear powder is prevented from being discharged outwardly from the discharge passage communicating with the outer peripheral side of the insulating base from the gap between the outer peripheral surface of the convex portion and the inner peripheral surface of the washer and reaching the sliding contact. it can.
[0016]
The invention according to a fourth aspect is characterized in that, in the third aspect, the axial dimension of the convex portion bulged on the outer peripheral surface of the cylindrical portion of the insulating base is made larger than the axial dimension of the washer.
[0017]
According to such a configuration, in addition to the effect of the third aspect, the width of the slit between the adjacent commutator pieces is regulated over a long span in the axial direction, so that the commutator pieces are prevented from falling in the circumferential direction. And the slit width can be more evenly secured.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a commutator unit to which the present invention is applied will be described with reference to the drawings.
[0019]
1 is an exploded perspective view of a commutator unit according to an embodiment of the present invention, FIG. 2 is a plan view after the commutator unit is assembled, FIG. 3 is a cross-sectional view taken along line AA ′ in FIG. 2, and FIG. FIG. Note that the commutator unit of the present embodiment has the same basic configuration as the conventional commutator unit described with reference to FIG. 6, and therefore, parts having the same functions are denoted by the same reference numerals.
[0020]
As shown in FIG. 1 to FIG. 4, the commutator unit includes an insulating base 10 made of an insulating material such as a thermoplastic resin formed in a cylindrical shape, and a plurality of commutator units attached to the outer periphery of the insulating base 10 made of a conductive metal. The individual commutator pieces 20 and an insulating washer 30 that press-fits the commutator pieces 20 against the outer peripheral surface of the insulating base 10 and press-fits the commutator pieces 20 into close contact with each other. And is composed of. The commutator unit according to this embodiment is applied to a motor having a four-pole six-slot structure, and uses six commutator pieces 20. The washer 30 may be an insulating washer made of an electrical insulator such as a synthetic resin, or a varistor element formed in a ring shape for erasing sparks generated when energization is switched.
[0021]
The commutator piece 20 includes a commutator portion 21 formed in an arc shape that is in sliding contact with the brush 40, and a riser portion 22 that is bent from one end side of the commutator portion 21 toward the radially outer side. Yes. The commutator piece 20 used in this commutator unit is made of a clad material in which copper is used as a base material and a thin contact material such as Ag-Cu ₆ is embedded in a commutator portion 21 that is in sliding contact with the brush 40. Yes. Further, the commutator piece 20 has a radius of curvature that matches the outer peripheral surface of the cylindrical portion 11 of the insulating base 10, and when attached to the insulating base 10, the tip of the shaft almost coincides with the end surface 11 a of the insulating base 10. The direction dimension and the width dimension S of the predetermined slit 23 are set to the circumferential dimension. Note that an armature winding (not shown) is connected to the riser unit 22.
[0022]
The insulating base 10 is integrally formed with a cylindrical portion 11 and a flange portion 12 having a diameter larger than that of the cylindrical portion 11 on the base end side, and a rotation shaft such as a motor (not shown) is fitted in the central through hole 15. The On the end surface of the flange portion 12, six positioning grooves 13 that engage with the riser portion 22 of the commutator piece 20 are radially formed at equal intervals. Further, an arcuate groove 17 for receiving the lower end portion 24 of the commutator piece 20 is formed at the base of the cylindrical portion 11 inside the positioning groove 13 so as to be connected to each positioning groove 13. These arc-shaped grooves 17 are separated in the circumferential direction by a ridge-like convex portion 16 bulging radially outward from the outer peripheral surface of the cylindrical portion 11.
[0023]
The convex portions 16 are formed in six locations at regular intervals of about 60 ° in the circumferential direction, and the side surfaces of the commutator portion 21 are in contact with the both side surfaces so that the width S of the slot 23 is kept constant. Is functioning.
[0024]
Further, as shown in FIG. 2, the convex portion 16 provided on the outer peripheral surface of the cylindrical portion 11 is formed to be lower in the radial direction by the dimension T than the outer peripheral surface of the commutator portion 21. That is, the bulging dimension of the convex portion 16 in the radial direction is set shorter than the plate thickness of the commutator piece 20. This means that the radius of the circumscribed circle formed by the six convex portions 16 is set smaller by the dimension T than the radius of the circle formed by the six commutator pieces 20. The dimension T is preferably about 1/3 to 1/2 of the plate thickness of the commutator piece 20. Incidentally, in this embodiment, when the radius of the circle formed by the commutator piece 20 is 1.1 mm and the plate thickness of the commutator portion 21 is 210 μm, the dimension T is configured to be about 70 μm.
[0025]
As described above, the means for tightly fixing the commutator piece 20 to the insulating base 10 depends on the pressing force by the washer 30, but when the convex portion 16 comes into contact with the inner peripheral surface of the washer 30, the pressing force is reduced. It will decrease. For this reason, since the convex part 16 is formed lower than the plate thickness of the commutator piece 20 in the radial direction by the dimension T, the contact between the insulating washer 30 and the convex part 16 can be avoided. Adhesion with 10 can be improved.
[0026]
3 and 4, the convex portion 16 extends in the axial direction from the end surface 31 on the side opposite to the flange of the washer 30 when the washer 30 abuts on the end surface of the flange 12. By doing so, the width S of the slit 23 is regulated over a long span in the axial direction, and the commutator piece 20 is reliably prevented from falling in the circumferential direction.
[0027]
Further, as a characteristic configuration of the present invention, as shown in FIG. 1, the flange portion 12 of the insulating base 10 has six discharge passages 18 formed in a concave shape at positions corresponding to the convex portions 16 and the radial direction. Is provided. When the washer 30 is fitted on the outer periphery of the commutator piece 20 and brought into contact with the flange portion 12, the discharge passage 18 is a gap between the inner peripheral surface 32 of the washer 30 and the outer peripheral surface 16 a of the convex portion 16. G communicates with the slit 23 and communicates with the outer peripheral side of the flange portion 13 of the insulating base 10. Accordingly, the discharge passage 18 connects the contact side and the non-contact side of the brush 40 and the commutator piece 20 and opens a closed space in which wear powder accumulates. By providing such a configuration, even if the wear powder enters the discharge passage 18 from the contact side, the wear powder is discharged to the non-contact side through the discharge passage 18 and accumulated. Insulation between the commutator pieces 20 can be reliably achieved.
[0028]
Now, after attaching the riser portion 22 and the lower end portion 24 of the commutator piece 20 to the positioning groove 13 and the arc-shaped groove 17 of the insulating substrate 10, the washer 30 is fitted along the outer peripheral surface of the commutator portion 21. The inner diameter dimension of the washer 30 is set to be approximately equal to the outer diameter dimension of the circle formed by the plurality of arc-shaped commutator sections 21, so that when the washer 30 is fitted to a position where it contacts the end face of the flange section 12, the commutator The piece 20 is pressed and positioned toward the center, and the width S of the slit 23 is made uniform by the convex portion 16. As a result, the six commutator pieces 20 are evenly arranged at an equal angle of 60 ° in the circumferential direction with respect to the outer peripheral surface of the cylindrical portion 11 of the insulating base 10 to complete the commutator unit.
[0029]
At this time, the insulating base 10 is formed with a discharge passage 18 communicating with the slit 23 and capable of discharging the wear powder outside the commutator unit, so that the brush 40 and the commutator piece 20 are brought into sliding contact with each other. The wear powder is discharged outside the commutator unit via the discharge passage 18 without being accumulated in the slit 23 or the gap G. Therefore, the adjacent commutator pieces 20 are not short-circuited by the abrasion powder, and each commutator piece 20 can be reliably insulated.
[0030]
In the embodiment shown in FIGS. 1 and 2, the present invention is applied to a commutator unit in which six commutator pieces 20 are arranged on the outer periphery of an insulating substrate 10. By increasing the number of commutator pieces 20, the switching efficiency of energization increases, and the torque can be increased as compared with a rotating electrical machine using three commutator pieces. On the other hand, when obtaining an equivalent torque, the size of the rotating electrical machine can be reduced by increasing the number of commutator pieces 20.
[0031]
Next, another embodiment according to the present invention will be described with reference to FIG. In order to clarify the structure, a part of the washer 30 is notched in FIG. In FIG. 5, the commutator unit includes a cylindrical insulating base 10, three commutator pieces 20 including a commutator portion 21 and a riser portion 22 attached to the outer periphery of the insulating base 10, and a commutator piece. It is comprised from the ring-shaped washer 30 inserted by 20 outer periphery. In the embodiment shown in FIG. 1, the convex portion 16 bulging from the outer peripheral surface of the insulating base 10 is provided at a position corresponding to the slit 23 formed between the adjacent commutator pieces 20. In the embodiment, the convex portion 16 does not exist on the outer peripheral surface of the insulating base 10. That is, the outer peripheral surface of the cylindrical portion of the insulating base 10 has a round shape with no change in curvature, and the commutator piece 20 has the riser portion 22 in the positioning groove 13 formed in the flange portion 12 of the insulating base 10. It is positioned by engaging.
[0032]
Also in this embodiment, similarly to the above-described embodiment, the insulating base 10 is provided with a discharge passage 18 communicating with the slit 23. Therefore, the abrasion powder generated by sliding the brush and the commutator piece 20 is discharged from the commutator unit through the discharge passage 18 without being accumulated in the slit 23. As a result, the commutator pieces 20 can be reliably insulated from each other.
[0033]
Needless to say, the present invention can be applied to a commutator unit other than the commutator unit including three or six commutator pieces 20.
[0034]
As mentioned above, although the invention made | formed by this inventor was concretely demonstrated based on embodiment, this invention is not limited to the said embodiment, A various deformation | transformation is possible in the range which does not deviate from the summary. For example, in the embodiment shown in FIG. 1, the convex portion 16 bulging and formed on the cylindrical portion 11 of the insulating base 10 extends larger in the axial direction than the thickness of the washer 30, but the axial dimension of the convex portion 16. May be extended to a range reaching the sliding contact between the commutator portion 21 and the brush. With this configuration, the width S of the slits 23 between the adjacent commutator portions 21 can be made uniform, and the assembly workability is improved.
[0035]
Contrary to the above configuration, even if the axial dimension of the convex portion 16 is made smaller than the thickness of the washer 30 in the axial direction, the effect of insulating the commutator portions 21 is the same.
[0036]
Further, a concave groove may be provided on the outer peripheral surface of the insulating base 10 corresponding to the slit 23, and the concave groove and the discharge passage 18 may be formed to communicate with each other. However, in this case, the commutator piece 20 needs to be accurately positioned by the positioning groove 13 or the like.
[0037]
Furthermore, in the above embodiment, the discharge passage 18 is formed to have the same width as the width S of the slit 23, but the width of the discharge passage 18 may be different from the width S of the slit 23.
[0038]
Further, the discharge passage 18 may have an opening on the end surface on the side opposite to the contact of the insulating base 10 in addition to the form having an opening on the outer peripheral side of the flange portion 12 of the insulating base 10.
[0039]
【The invention's effect】
As described above, according to the present invention, since the form discharge passage communicating with the outer peripheral side of the insulating substrate from each provided with slits into a plurality of commutator segments, abrasion powder is accumulated in the slit or gap portions Without being discharged to the outer peripheral side of the commutator unit via the discharge passage. As a result, insulation between adjacent commutator pieces can be reliably achieved.
[0040]
Further, according to the present invention, since the discharge passage is opened on the outer peripheral side of the flange portion , the wear powder is outwardly exposed from the outer peripheral side of the flange portion opposite to the sliding contact where the commutator piece and the brush are in sliding contact. Can be prevented from reaching the sliding contact, and insulation between the commutator pieces can be reliably ensured.
[0041]
Further, according to the present invention, the cylindrical portion of the insulating base is formed with a ridge-like convex portion that is lower than the outer peripheral surface of the commutator piece at a position corresponding to the slit, so that in addition to the above effects, The width of the slits between the commutator pieces to be controlled can be uniformly regulated by the convex portions. At the same time, when the washer is inserted, only the commutator piece is pressed without the inner peripheral surface of the washer contacting the convex portion, so that the adhesion between the commutator piece and the insulating base can be improved. Furthermore, wear powder is discharged from the gap between the outer peripheral surface of the convex portion and the inner peripheral surface of the washer to the outer peripheral side of the insulating base and is prevented from reaching the sliding contact. it can.
[0042]
Furthermore, according to the present invention, since the axial dimension of the convex portion is larger than the axial dimension of the washer, the width of the slit between adjacent commutator pieces is restricted over a long span in the axial direction. As a result, the commutator piece is prevented from falling in the circumferential direction, and the width of the slit is more evenly secured.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view of a commutator unit according to an embodiment of the present invention.
FIG. 2 is a plan view after the commutator unit is assembled.
3 is a cross-sectional view taken along the line AA ′ in FIG.
4 is an enlarged view of a main part in FIG. 3. FIG.
FIG. 5 is a perspective view of a commutator unit according to another embodiment of the present invention.
FIG. 6 is an exploded perspective view of a conventional commutator unit.
FIG. 7 is a partial cross-sectional view of a conventional commutator unit.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Insulation base | substrate 11 Cylindrical part 12 Flange part 13 Positioning groove | channel 16 Convex part 18 Discharge passage 20 Commutator piece 21 Commutator part 22 Riser part 23 Slit 30 Washer 40 Brush S Slit width

Claims (4)

A plurality of commutator pieces having a commutator portion formed in an arc shape and a riser portion connected to the commutator portion are arranged with slits between the commutator pieces on the outer peripheral surface of the cylindrical insulating base. In addition, in a commutator unit in which a ring-shaped washer is fitted to the outer periphery on the riser side and the commutator piece is fixed to the insulating base, the insulating base is connected to the insulating base from the slit. A commutator unit having a discharge passage communicating with an outer peripheral side . The base end side of the insulating substrate, a flange portion for mounting the washer is provided, in claim 1, characterized in that to form each opening of the plurality of discharge passage communicating with the slits on the outer periphery of the flange portion The commutator unit described. On the outer peripheral surface of the cylindrical portion of the insulating base, a ridge-like convex portion lower than the outer peripheral surface of the commutator portion is bulged at a position corresponding to each slit, and the outer peripheral surface of the convex portion and the inner peripheral surface of the washer 2. The commutator unit according to claim 1, wherein a discharge passage is formed from a gap portion between the first and second insulating bases to the outer peripheral side of the insulating base.  4. The commutator unit according to claim 3, wherein the axial dimension of the convex portion bulging on the outer peripheral surface of the cylindrical portion of the insulating base is made larger than the axial dimension of the washer.

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