JP3664871B2 - Plastic magnet rotor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a plastic magnet rotor formed by integrally molding a plastic magnet used for a rotor of a brushless motor, a stepping motor or the like with a shaft.
[0002]
[Prior art]
FIG. 7 is a conventional plastic magnet rotor formed by integrally molding a plastic magnet with a shaft, FIG. 7A is a perspective view thereof, and FIG. 7B is a sectional view thereof.
In the figure, 1 is a shaft, 2 is a plastic magnet part, 3 is a magnetic pole part, 4 is an inner cylinder, 5 is a connecting part, and 6 is a linear rib.
[0003]
The plastic magnet portion 2 is composed of a magnetic pole portion 3, an inner cylinder 4, a connecting portion 5, and a linear rib 6.
The magnetic pole part 3 is connected to the inner cylinder 4 integrated with the shaft 1 by the connecting part 5. The connecting portion 5 is provided with linear ribs 6 for improving strength and dimensional accuracy.
In general, a plastic magnet rotor is formed by integrally molding the above-described structure, and thus can be easily manufactured, can reduce processing costs, and is optimal for a small-capacity home synchronous motor.
[0004]
[Problems to be solved by the invention]
By the way, in the conventional plastic magnet rotor having the above-described configuration, the improvement of the characteristics of the plastic magnet rotor is performed by using a plastic magnet having a high magnetic flux density and by increasing the thickness of the magnetic pole part and the rib. There were problems such as an increase in product weight.
The present invention has been made to solve the above-described problems, and an object of the present invention is to obtain a plastic magnet rotor capable of improving performance, reducing weight, reducing costs, and improving cooling efficiency.
[0005]
[Means for Solving the Problems]
A package for a semiconductor device according to a first aspect of the present invention is a plastic magnet rotor in which a shaft and a plastic magnet portion are integrally formed, and is provided between the shaft and the magnetic pole portion of the plastic magnet portion, and the magnetic flux density of the magnetic pole portion. The magnetic flux density enhancing means is a rib that directly couples the magnetic pole part and the shaft, and the rib is disposed so as to be inclined in the axial direction .
[0008]
A plastic magnet rotor according to a second aspect of the present invention is the plastic magnet rotor according to the first aspect of the present invention, wherein the rib has a shape that becomes thicker toward the outer peripheral side.
[0009]
A plastic magnet rotor according to a third aspect of the present invention is the plastic magnet rotor according to the first or second aspect, wherein the rib is elongated in the axial direction by a volume of volume connecting the magnetic pole portion and the shaft.
[0011]
A plastic magnet rotor according to a fourth aspect of the present invention is the plastic magnet rotor according to any one of the first to third aspects, wherein the number of the ribs is the same as the number of poles of the magnetic pole portion.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described below with reference to the drawings.
Embodiment 1 FIG.
1 shows Embodiment 1 of the present invention, FIG. 1A is a perspective view thereof, and FIG. 1B is a sectional view thereof. 1, parts corresponding to those in FIG. 7 are denoted by the same reference numerals, and detailed description thereof is omitted.
In the figure, reference numeral 2A denotes a plastic magnet part, and 6A denotes a rib as a magnetic flux density enhancing means that is installed in the connecting part 5 and connects the magnetic pole part 3 and the inner cylinder 4.
FIG. 2 is an enlarged view of the rib 6A.
As can be clearly seen from FIG. 2, the rib 6A has a shape that becomes thicker toward the outer peripheral side. In this case, the plastic magnet portion 2A includes the magnetic pole portion 3, the inner cylinder 4, the connecting portion 5, and the rib 6A.
[0013]
By the way, a plastic magnet is a resin in which magnetic powder is mixed with plastic, and is a resin that can be injection-molded like a general-purpose plastic. Although there are advantages in terms of manufacturing such that the shape can be arbitrarily selected as compared with permanent magnets such as sintering, handling is complete, and integral molding is possible, the material cost increases because it is not a general-purpose plastic. Therefore, the amount of plastic magnets to be used must be reduced and reduced in weight, but there are also recent energy-saving trends, and it is required to realize weight reduction and improved characteristics at the same time.
[0014]
Here, the magnetic pole part 3 is connected to the inner cylinder 4 integrated with the shaft 1 by the connecting part 5, and the connecting part 5 is provided with a rib 6 </ b> A for improving strength and dimensional accuracy.
As described above, the rib 6A is thicker toward the outer peripheral side (see FIG. 2).
Here, the thickness of the rib 6A on the inner cylinder 4 side is determined from ensuring the strength and the moldability of the plastic magnet, and is made as thin as possible. The thickness on the magnetic pole part 3 side is determined from the amount of plastic magnet used and the pole pitch, and is made as thick as possible. In consideration of the balance of magnetic flux, the same number as the number of poles is arranged at the pole center.
[0015]
When the plastic magnet rotor having the above configuration is magnetized, the thicker rib 6A can be used as a magnetic path toward the outer periphery, and the thickness of the magnetic pole portion 3 and the rib 6 of the plastic magnet rotor shown in FIG. As with, the magnetic flux density increases, the characteristics can be improved, the amount of plastic magnet used can be reduced, and the weight can be reduced.
[0016]
Thus, in this embodiment, since the thickness of the rib arranged in the connecting portion that couples the magnetic pole portion and the shaft is increased toward the outer peripheral side, the magnetic flux density is increased and the characteristics are improved. The amount of plastic magnets used can be reduced, which makes it possible to improve performance, reduce weight, and reduce costs.
[0017]
Embodiment 2. FIG.
3 shows Embodiment 2 of the present invention, FIG. 3A is a perspective view thereof, and FIG. 3B is a sectional view thereof. 3, parts corresponding to those in FIG. 7 are denoted by the same reference numerals, and detailed description thereof is omitted.
In the figure, 2B is a plastic magnet part, 6B is a rib as linear magnetic flux density enhancing means for connecting the magnetic pole part 3 and the inner cylinder 4, and 7 is a cavity.
In this case, the plastic magnet portion 2B includes the magnetic pole portion 3, the inner cylinder 4, and the linear rib 6B. That is, in the second embodiment, the connecting portion 5 used in the first embodiment is not necessary. Further, the rib 6B is longer in the axial direction than the rib 6 of FIG.
[0018]
Here, the inner cylinder 4 integrated with the shaft 1 and the magnetic pole part 3 are connected by a linear rib 6B, and this rib 6B has a rib volume corresponding to the volume of the connecting part of the plastic magnet rotor of FIG. The axial length increases in volume.
The plastic magnet rotor of the present embodiment has a configuration in which the connecting portion is substantially eliminated from the conventional plastic magnet rotor (FIG. 7), but the strength is increased by increasing the axial length of the linear rib 6B. Secured. In addition, by increasing the length of the linear rib 6B, the magnetic flux density increases simultaneously with securing the strength, and the characteristics can be improved without increasing the total amount of the plastic magnet.
[0019]
As described above, in the present embodiment, the characteristics can be improved without increasing the weight and the cost by coupling the magnetic pole portion and the shaft with substantially only the rib.
[0020]
Embodiment 3 FIG.
4 shows Embodiment 3 of the present invention, FIG. 4A is a perspective view thereof, and FIG. 4B is a sectional view thereof. 4, portions corresponding to those in FIGS. 1 and 3 are denoted by the same reference numerals, and detailed description thereof is omitted.
In the figure, 2C is a plastic magnet portion, and 6C is a rib as magnetic flux density enhancing means for connecting the magnetic pole portion 3 and the inner cylinder 4. The rib 6C has a shape that becomes thicker toward the outer peripheral side.
In this case, the plastic magnet portion 2C includes the magnetic pole portion 3, the inner cylinder 4, and the rib 6C. That is, in the third embodiment, the connecting portion 5 used in the first embodiment is not necessary, and the rib 6C has a long axial length. In other words, the present embodiment is substantially a combination of the first and second embodiments.
[0021]
Here, the inner cylinder 4 integrated with the shaft 1 and the magnetic pole portion 3 are connected by a rib 6C which becomes thicker toward the outer peripheral side, and this rib 6C is the connecting portion of the plastic magnet rotor of FIG. The axial length is such that the volume of the rib increases by the volume of. The plastic magnet rotor of the present embodiment has a configuration in which the connecting portion is substantially abolished from the plastic magnet rotor (FIG. 1) of the first embodiment, but the axial direction of the rib 6C becomes thicker toward the outer peripheral side. Strength is secured by increasing the length. Further, by increasing the thickness of the rib 6C that becomes thicker toward the outer peripheral side, the magnetic flux density increases at the same time as securing the strength, and the characteristics can be improved without increasing the total amount of the plastic magnet.
[0022]
Thus, in this embodiment, the magnetic flux density is increased and the characteristics are improved by performing the coupling of the magnetic pole portion and the shaft only with the ribs that become thicker toward the outer peripheral side. The amount of use can be reduced, thereby improving the characteristics without increasing the weight and cost, and improving the performance, reducing the weight, and reducing the cost.
[0023]
Embodiment 4 FIG.
5 shows Embodiment 4 of the present invention, FIG. 5A is a perspective view thereof, and FIG. 5B is a sectional view thereof. 5, parts corresponding to those in FIG. 3 are denoted by the same reference numerals, and detailed description thereof is omitted.
In the figure, 2D is a plastic magnet portion, and 6D is a rib as a linear magnetic flux density enhancing means for connecting the magnetic pole portion 3 and the inner cylinder 4.
In this case, the plastic magnet portion 2D includes the magnetic pole portion 3, the inner cylinder 4, and the linear rib 6D. That is, even in the fourth embodiment, the connecting portion 5 used in the first embodiment is not necessary. Further, the rib 6D is elongated in the axial direction and is inclined in the axial direction.
[0024]
Here, the inner cylinder 4 integrated with the shaft 1 and the magnetic pole portion 3 are connected by a linear rib 6D, and this rib 6D has a rib volume corresponding to the volume of the connecting portion of the plastic magnet rotor in FIG. The axial length is such that the volume increases, and is inclined in the axial direction.
As in the second embodiment, the plastic magnet rotor of the present embodiment has a configuration in which the connecting portion is eliminated from the plastic magnet rotor, and the strength is ensured by increasing the axial length of the linear rib 6D. Yes. In addition, by increasing the length of the linear rib 6D, the magnetic flux density increases at the same time as securing the strength, and the characteristics can be improved without increasing the total amount of the plastic magnet.
Further, when the plastic magnet rotor of this embodiment is incorporated into an electric motor and operated, the rib 6D, which becomes thicker toward the outer peripheral side inclined in the axial direction, causes convection in the cavity 7 and the magnetic pole part 3, and the plastic magnet part 2D. Is soaked and cooled.
[0025]
As described above, in this embodiment, the coupling between the magnetic pole portion and the shaft is substantially performed only by the rib, so that the characteristics can be improved without increasing the weight and the cost. By inclining, the convection occurs and the cooling efficiency is improved.
[0026]
Embodiment 5 FIG.
6 shows Embodiment 5 of the present invention, FIG. 6A is a perspective view thereof, and FIG. 6B is a sectional view thereof. 6, parts corresponding to those in FIG. 4 are denoted by the same reference numerals, and detailed description thereof is omitted.
In the figure, 2E is a plastic magnet portion, and 6E is a rib as linear magnetic flux density enhancing means for connecting the magnetic pole portion 3 and the inner cylinder 4. The rib 6E has a shape that becomes thicker toward the outer peripheral side.
In this case, the plastic magnet portion 2E includes the magnetic pole portion 3, the inner cylinder 4, and the rib 6D. That is, even in the fifth embodiment, the connecting portion 5 used in the first embodiment is not necessary. Further, the rib 6E is elongated in the axial direction and is inclined in the axial direction.
[0027]
Here, the inner cylinder 4 integrated with the shaft 1 and the magnetic pole portion 3 are connected by a linear rib 6E, and this rib 6E has a rib volume corresponding to the volume of the connecting portion of the plastic magnet rotor of FIG. The axial length is such that the volume increases, and is inclined in the axial direction.
As in the third embodiment, the plastic magnet rotor of the present embodiment has a configuration in which the connecting portion is eliminated from the plastic magnet rotor, and the strength is ensured by increasing the axial length of the linear rib 6E. Yes. In addition, by increasing the length of the linear rib 6E, the magnetic flux density increases simultaneously with securing the strength, and the characteristics can be improved without increasing the total amount of the plastic magnet.
Further, when the plastic magnet rotor of this embodiment is incorporated in an electric motor and operated, the rib 6E that becomes thicker toward the outer peripheral side inclined in the axial direction causes convection in the cavity 7 and the magnetic pole part 3, and the plastic magnet part 2E. Is soaked and cooled.
[0028]
As described above, in this embodiment, the coupling between the magnetic pole portion and the shaft is substantially performed only by the rib, so that the characteristics can be improved without increasing the weight and the cost. By inclining, the convection occurs and the cooling efficiency is improved.
[0029]
【The invention's effect】
According to the first aspect of the present invention, in the plastic magnet rotor in which the shaft and the plastic magnet portion are integrally formed, the magnetic flux density increasing means is provided between the shaft and the magnetic pole portion of the plastic magnet portion and increases the magnetic flux density of the magnetic pole portion. Because it has high performance, light weight, and low cost , and the magnetic flux density enhancing means is a rib that directly connects the magnetic pole part and the shaft, the weight and cost are increased. Therefore, the characteristics can be improved, and the ribs are arranged so as to be inclined in the axial direction. Therefore, there is an effect that convection occurs in the cavity and the magnetic pole portion, and the cooling efficiency is improved .
[0032]
According to the invention of claim 2 , since the rib has a shape that becomes thicker toward the outer peripheral side, it is possible to improve the characteristics by increasing the magnetic flux density and reducing the weight and the cost. effective.
[0033]
According to the invention of claim 3 , since the rib is elongated in the axial direction by the volume integral connecting the magnetic pole part and the shaft, there is an effect that the magnetic flux density increases and the characteristics can be improved.
[0035]
According to the invention of claim 4 , since the ribs are arranged at the pole center as many as the number of poles of the magnetic pole part, the magnetic flux of the magnetic pole part is balanced, and there is an effect that it is possible to contribute to improvement of characteristics.
[Brief description of the drawings]
FIGS. 1A and 1B show a first embodiment of the present invention, in which A is a perspective view and B is a cross-sectional view thereof. FIG.
FIG. 2 is an enlarged view showing a main part of the first embodiment of the present invention.
FIGS. 3A and 3B show a second embodiment of the present invention, in which A is a perspective view and B is a cross-sectional view thereof. FIG.
4 shows Embodiment 3 of the present invention, in which A is a perspective view and B is a cross-sectional view thereof. FIG.
5 shows Embodiment 4 of the present invention, in which A is a perspective view and B is a cross-sectional view thereof. FIG.
6 shows Embodiment 5 of the present invention, in which A is a perspective view and B is a cross-sectional view thereof. FIG.
FIG. 7 shows a conventional plastic magnet rotor, in which A is a perspective view and B is a cross-sectional view thereof.
[Explanation of symbols]
1 axis, 2A-2E plastic magnet part, 3 magnetic pole part, 4 inner cylinder, 5 connection part, 6A-6E, rib, 7 cavity.

Claims (4)

In the plastic magnet rotor in which the shaft and plastic magnet part are integrally molded,
The magnetic flux density enhancing means is provided between the shaft and the magnetic pole portion of the plastic magnet portion and increases the magnetic flux density of the magnetic pole portion, and the magnetic flux density enhancing means is a rib for directly coupling the magnetic pole portion and the shaft. A plastic magnet rotor characterized in that the ribs are arranged to be inclined in the axial direction . The plastic magnet rotor according to claim 1 , wherein the rib has a shape that becomes thicker toward an outer peripheral side . 3. The plastic magnet rotor according to claim 1 , wherein the rib is elongated in the axial direction by a volume integral connecting the magnetic pole portion and the shaft . The plastic magnet rotor according to any one of claims 1 to 3, wherein the rib is arranged at the pole center in the same number as the pole number of the magnetic pole portion .

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