JP2010172089A - Dc motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a DC motor which prevents cracks or the like of magnet plates, and is reduced in sound and noise. <P>SOLUTION: A stator 2 related to the DC motor is composed of a magnetic material, formed in a hexagonal cylindrical shape, and provided with a yoke 3 having six flat plates 4 which are connected to one another in series and formed in a flat-plate shape, and six magnet plates which are formed of sintered bodies with neodymium as main materials. The magnet plates are attached to inner walls of the flat plates formed at the yoke 3, respectively. The magnet plates are composed of first and second magnet pieces (M1, M2) which are arranged in proximity with each other, respectively. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a DC motor, and more particularly to a DC motor including a hexagonal cylindrical yoke.

  FIG. 9 shows an example of a DC motor 100 including a hexagonal cylindrical yoke 30 as an example of a DC motor. The stator 20 constituting the DC motor 100 includes a yoke 30 and six plate-shaped magnets M attached to the inner wall P 1 of the yoke 30. The yoke 30 has six flat plate portions P connected in series with each other by the joint portion C, and is formed in a hexagonal cylinder shape. Each of the six magnets M is attached to the inner wall P1 of each flat plate portion P by an adhesive (see, for example, Patent Document 1 and Patent Document 2).

JP 2005-20914 A JP 2007-104758 A

  Here, when the flat magnet P attached to the yoke 30 is formed of a sintered body (hereinafter referred to as “neodymium sintered body”) using neodymium as a main raw material, the DC motor 100 is driven. In addition, when the temperature of the stator 20 rises to a high temperature due to an increase in the ambient temperature, there is a possibility that the magnet P itself may crack due to the rise in the temperature of the stator 20, and adhesion that fixes the magnet P to the yoke 30. There is a possibility that the adhesive layer formed by the agent cracks and the magnet P falls off the yoke 30. Hereinafter, this point will be described with reference to FIG.

  FIG. 10 is a partially enlarged view of the stator 20 as seen from the direction of the arrow B in FIG. When the temperature of the stator 20 rises and becomes high, the yoke 30 expands in the longitudinal direction y due to an increase in volume accompanying the temperature rise. On the other hand, the magnet P formed of neodymium sintered body also increases in volume as the temperature rises. However, since the expansion rate in the thickness direction z is large due to the influence of the orientation direction during production such as sintering, the thickness direction z And contracts in the longitudinal direction y and the lateral direction x. That is, when attention is paid to the longitudinal direction y, the yoke 30 expands in the longitudinal direction y, whereas the magnet P contracts in the longitudinal direction y, and the deformation direction of the yoke 30 and the magnet P is reversed in the longitudinal direction y. Become. Therefore, thermal stress is generated in the magnet P itself and the adhesive layer due to a rise in the temperature of the stator 20 or the like.

  Therefore, when the flat plate-shaped magnet P is formed of a neodymium sintered body, when the temperature of the stator 20 rises and becomes high, the magnet P itself is cracked or the magnet P is fixed to the yoke 30. There is a possibility that a crack may occur in the adhesive layer formed by the adhesive.

  Furthermore, the DC motor is required to reduce sound and vibration generated when the motor is driven. As a cause of this sound and vibration, first, cogging torque is cited. That is, the DC motor is also required to reduce the cogging torque generated in the DC motor in order to reduce sound and vibration generated during driving.

  Therefore, the present invention has been made in view of the above-described circumstances, and even when the temperature of a stator including a plate-shaped magnet formed of a neodymium sintered body is increased and becomes a temperature, the neodymium sintering is performed. It is an object of the present invention to provide a direct current motor that can prevent cracks and the like of a plate-like magnet formed by a body, reduce cogging torque, and reduce sound and vibration generated during driving.

  In order to solve the above problems, a direct current motor of the present invention is made of a magnetic material, is formed in a hexagonal cylinder shape, and has a yoke having six flat plate portions connected in series with each other, and neodymium as a main raw material. A stator that is attached to each inner wall of the flat plate portion formed on the yoke, a rotating shaft, and the rotating shaft. An armature core having a substantially ring-shaped core body and a plurality of teeth integrally formed at equal intervals in the circumferential direction from the outer peripheral surface of the core body toward the radially outer side, and the armature core An armature coil having a plurality of windings wound around the formed teeth, and attached to the rotating shaft in proximity to the armature core. A DC motor including a commutator having a plurality of commutator pieces on an outer peripheral surface and including an armature that is rotatably disposed inside the stator, wherein the number of teeth and the number of commutator pieces are both 9, Each of the magnet plates is formed of first and second magnet pieces arranged close to each other.

  In this way, the length of the first and second magnet pieces attached to the yoke in the vertical direction or the horizontal direction is formed by configuring the magnet plate from the first and second magnet pieces arranged close to each other. Can be shortened. Therefore, when the temperature of the stator becomes high, the contraction length in the vertical direction or the horizontal direction of the first and second magnet pieces can be shortened, and cracking of the first and second magnet pieces can be prevented. Can be prevented.

  Further, in the DC motor of the present invention, the first and second magnet pieces forming the magnet plate are arranged in the direction of the central axis of the yoke, and the first magnet piece is a flat plate portion formed on the yoke. The second magnet piece is disposed at a predetermined angle from the axial center line of the flat plate portion formed on the yoke and is opposite to the circumferential direction by one angle. It is characterized by being arranged with a predetermined angular shift in the circumferential direction.

  As described above, the first and second magnet pieces are arranged side by side in the direction of the central axis of the yoke, and the first and second magnet pieces are arranged at a predetermined angle in the circumferential direction of the yoke. Thus, when the armature rotates, the change in the amount of magnetic flux flowing through the teeth formed in the armature core provided in the armature becomes gentle. Therefore, the cogging torque generated in the DC motor is reduced.

According to the present invention, the contraction length of the first and second magnet pieces in the vertical direction or the horizontal direction can be shortened, and cracking of the first and second magnet pieces can be prevented. Further, the cogging torque generated in the DC motor can be reduced.

It is the figure seen from the axial direction of the DC motor in the 1st Embodiment of this invention. It is sectional drawing of the stator seen from the AA cross section in FIG. It is an expanded view of the stator of the 1st Embodiment of this invention. It is a figure explaining the fall of the cogging torque of the DC motor of the 1st Embodiment of this invention. It is a figure explaining the relationship between the cogging torque of the DC motor of the 1st Embodiment of this invention, and the shift | offset | difference angle of a 1st and 2nd magnet piece. It is a figure explaining the deformation | transformation of the 1st and 2nd magnet piece of the 1st Embodiment of this invention. It is an expanded view of the stator of the 2nd Embodiment of this invention. It is an expanded view of the stator of the 3rd Embodiment of this invention. It is the figure seen from the axial direction of the stator with which the DC motor of a prior art is equipped. It is a figure explaining the deformation | transformation of the magnet of a prior art.

  Next, a first embodiment of the present invention will be described with reference to FIG. 1, FIG. 2, and FIG. As shown in FIG. 1, the DC motor 1 of the present embodiment includes a stator 2 and an armature 6 that is rotatably disposed inside the stator 2. The stator 2 includes a yoke 3 formed in a hexagonal cylinder shape and six magnet plates 5 attached to the yoke 3. The yoke 3 has six flat plate portions 4 connected in series with each other by a connecting portion 3a. And the magnet plate 5 is attached to each of the six flat plate parts 4 with an adhesive agent. Details of the magnet plate 5 attached to the flat plate portion 4 will be described later.

  The armature 6 includes a rod-shaped rotating shaft 7, an annular core body 8 a that is attached to the rotating shaft 7, and a plurality of teeth 8 b that are integrally formed radially outward from the outer peripheral surface of the core body 8 a. An armature core 8 and an armature coil 9 attached to the armature core 8 are provided. The armature coil 9 includes a plurality of windings 9a wound around the teeth 8b.

  Next, based on FIG. 2 and FIG. 3, the detail of the magnet plate 5 attached to the flat plate part 4 is demonstrated. The magnet plate 5a is attached to the flat plate portion 4a formed on the yoke 3 with an adhesive. More specifically, the magnet plate 5a is attached to the flat plate portion 4a, the magnet plate 5b is attached to the flat plate portion 4b, the magnet plate 5c is attached to the flat plate portion 4c by an adhesive, the magnet plate 5d is attached to the flat plate portion 4d, and the magnet plate 5e is The magnet plate 5f is attached to the flat plate portion 4e by an adhesive.

  The magnet plate 5 is composed of thin and substantially rectangular parallelepiped first and second magnet pieces (M1, M2), and the first and second magnet pieces (M1, M2) are close to each other, and the yoke 3 Placed in. The first and second magnet pieces (M1, M2) are formed of a neodymium sintered body.

  In the present embodiment, the first and second magnet pieces (M1, M2) forming the magnet plate 5 are arranged side by side in the central axis direction a of the yoke 3, which is the arrangement direction of the central axis Ly of the yoke 3. Arranged. The first magnet piece M1 is shifted from the axial center line L0 of the flat plate portion 4 formed on the yoke 3 by a predetermined angle θ in the circumferential direction r of one yoke when viewed from the central axis Ly of the yoke 3. The second magnet piece is disposed in the yoke 3 in the circumferential direction r of the other yoke opposite to the circumferential direction r of one yoke from the axial center line L0 of the flat plate portion 4 similarly formed in the yoke 3. The central axis Ly is disposed at a predetermined angle θ.

  That is, the axial center line L1 of the first magnet piece M1 is arranged at a predetermined angle θ in the circumferential direction r of one yoke from the axial center line L0, and the axial center line of the second magnet piece M1. The line L2 is disposed at a predetermined angle θ from the axial center line L0 in the circumferential direction r of another yoke opposite to the circumferential direction r of one yoke. In the present embodiment, the angle θ is set to 3.75 degrees, but it is needless to say that the angle θ is not limited to 3.75 degrees. The angle may be 4 degrees or less.

  Next, since the magnet plate 5 is formed of the first and second magnet pieces (M1, M2), that is, two magnet pieces, the first temperature is increased even when the temperature of the stator 2 is increased. And the second magnet piece (M1, M2) itself is difficult to break, and a crack occurs in the adhesive layer formed between the first and second magnet pieces (M1, M2) and the yoke 3. The difficulty will be described with reference to FIG.

  FIG. 4 shows a partially enlarged view of the stator 2, and the yoke 3 and the first and second magnet pieces (when the temperature of the stator 2 rises and the temperature of the stator 2 becomes high) are shown. M1, M2) shows the form of expansion or contraction. As shown in the figure, when the temperature of the stator 2 rises and the temperature of the stator 2 becomes high, the yoke 3 expands in the longitudinal direction y due to the increase in volume accompanying the temperature rise. On the other hand, the magnet P formed of neodymium sintered body has a large expansion coefficient in the thickness direction z due to an increase in volume due to a temperature rise due to the influence of the orientation direction during production such as sintering. The second magnet piece (M1, M2) expands greatly in the thickness direction z, while contracting in the horizontal direction x and the vertical direction y.

  That is, when attention is paid to the longitudinal direction y, the yoke 30 expands in the longitudinal direction y, whereas the magnet P contracts in the longitudinal direction y, and the deformation direction of the yoke 30 and the magnet P is reversed in the longitudinal direction y. Become. Therefore, thermal stress is generated in the magnet P itself and the adhesive layer due to a rise in the temperature of the stator 20 or the like.

  As described above, thermal stress is formed on the first and second magnet pieces (M1, M2) itself and the adhesive layer. In the present embodiment, the magnet plate 5 includes the first and second magnet pieces. (M1, M2), that is, formed by two magnet pieces. For this reason, the longitudinal length Ly of the entire magnet plate 5 is divided into two substantially half lengths (Ly / 2) by the first and second magnet pieces (M1, M2). , The longitudinal direction of the first and second magnet pieces (M1, M2) as compared with the contraction length of the longitudinal direction y of the magnet M having the length Ly in the longitudinal direction y as shown in FIG. The contraction length of y is halved and set short.

  For this reason, the length of the first and second magnets (M1, M2) contracting in the longitudinal direction y due to the temperature rise is shortened, and the first and second magnet pieces (M1, M2) themselves and the adhesive layer are reduced. The formed thermal stress is reduced more than the thermal stress formed on the magnet M shown as a conventional example in FIG. Therefore, when the magnet plate 5 is formed by the first and second magnet pieces (M1, M2), that is, two magnet pieces, the temperature of the stator 2 rises, and even when the temperature becomes high, the first In addition, the second magnet piece (M1, M2) itself is difficult to break, and the crack generated in the adhesive layer formed between the first and second magnet pieces (M1, M2) and the yoke 3 is less likely to occur. .

  Next, the reduction in sound and vibration generated in the DC motor 1 of the present embodiment will be described. As described above, the first and second magnet pieces (M1, M2) of the DC motor 1 of the present embodiment are arranged side by side in the central axis direction a of the yoke, and the first and second magnet pieces are arranged. The magnet pieces are arranged at a predetermined angle in the circumferential direction r of the yoke. Therefore, when the armature 6 rotates, the change in the amount of magnetic flux flowing from the first and second magnet pieces (M1, M2) to the teeth 8b formed in the armature core 8 provided in the armature 6 becomes gradual. . Therefore, the cogging torque generated in the DC motor 1 is reduced.

  As described above, the reduction in the cogging torque generated in the DC motor 1 will be described with reference to FIGS. FIG. 5 shows that the deviation angles θ of the axial center lines L1, L2 of the first and second magnet pieces (M1, M2) from the axial center line L0 shown in FIG. The cogging torque generated in the DC motor 1 when the armature 6 provided in the DC motor 1 is rotated will be described. In the figure, the cogging torque generated in the DC motor 1 when the deviation angle θ is 0 degrees is indicated by a broken line, and the cogging torque generated in the DC motor 1 when the deviation angle θ is 2.5 degrees is indicated by a solid line.

  As shown in the figure, the cogging torque generated in the DC motor 1 when the deviation angle θ is 2.5 degrees is larger than the cogging torque generated in the DC motor 1 when the deviation angle θ is 2.5 degrees. Will be reduced. That is, the first and second magnet pieces (M1, M2) of the DC motor 1 are arranged side by side in the central axis direction a of the yoke, and the first and second magnet pieces are arranged in the circumferential direction of the yoke. The cogging torque is reduced by disposing r at a predetermined angle (2.5 degrees in the figure).

  Further, in FIG. 6, the shift angle θ between the axial center lines L1 and L2 of the first and second magnet pieces (M1, M2) from the axial center line L0 shown in FIG. Sometimes the cogging torque generated in the DC motor 1 is shown. As shown in the figure, the cogging torque generated in the DC motor 1 is small when the deviation angle θ is 2 degrees or more and 4.5 degrees or less, and the deviation angle θ is 3.75 degrees (θ = 3.75 degrees). To the minimum. Therefore, as described above, in the DC motor 1 of the present embodiment in which the deviation angle θ is set to 3.75 degrees, the cogging torque is set to be small.

  In this way, the first and second magnet pieces (M1, M2) of the DC motor 1 are arranged side by side in the central axis direction a of the yoke, and the first and second magnet pieces are arranged on the yoke. By being shifted by a predetermined angle (2.5 degrees in the figure) in the circumferential direction r, the cogging torque is reduced and the sound and vibration generated in the DC motor 1 are reduced.

  Next, the DC motor 1 according to the second embodiment will be described with reference to FIG. The direct current motor 1 of the second embodiment is different from the direct current motor 1 of the first embodiment in the shape and yoke of the first and second magnet pieces (M1, M2) forming the magnet plate 5. Only the attachment position to 3 is different, and the other parts are the same. Therefore, only the shape of the first and second magnet pieces (M1, M2) forming the magnet plate 5 and the attachment position to the yoke 3 will be described, and description of other parts will be omitted.

  In the DC motor 1 of the second embodiment, the first and second magnet pieces (M1, M2) forming the magnet plate 5 are arranged in the direction of the central axis of the yoke 3, which is the arrangement direction of the central axis Ly of the yoke 3. a are arranged side by side. For this reason, the longitudinal length Ly of the entire magnet plate 5 is divided into two substantially half lengths (Ly / 2) by the first and second magnet pieces (M1, M2). , The longitudinal direction of the first and second magnet pieces (M1, M2) as compared with the contraction length of the longitudinal direction y of the magnet M having the length Ly in the longitudinal direction y as shown in FIG. The contraction length of y is halved and set short.

  Therefore, similarly to the first embodiment, the DC motor 1 of the second embodiment has a short length that contracts in the longitudinal direction y due to the temperature rise of the first and second magnets (M1, M2). Thus, the thermal stress formed on the first and second magnet pieces (M1, M2) itself and the adhesive layer is reduced more than the thermal stress formed on the magnet M shown as a conventional example in FIG. Therefore, when the magnet plate 5 is formed by the first and second magnet pieces (M1, M2), that is, two magnet pieces, the temperature of the stator 2 rises, and even when the temperature becomes high, the first In addition, the second magnet piece (M1, M2) itself is difficult to break, and the crack generated in the adhesive layer formed between the first and second magnet pieces (M1, M2) and the yoke 3 is less likely to occur. .

  Next, a DC motor 1 according to a third embodiment will be described with reference to FIG. The direct current motor 1 of the third embodiment is different from the direct current motor 1 of the first embodiment in the shape and yoke of the first and second magnet pieces (M1, M2) forming the magnet plate 5. Only the attachment position to 3 is different, and the other parts are the same. Therefore, only the shape of the first and second magnet pieces (M1, M2) forming the magnet plate 5 and the attachment position to the yoke 3 will be described, and description of other parts will be omitted.

  In the DC motor 1 of the third embodiment, the first and second magnet pieces (M1, M2) forming the magnet plate 5 are arranged side by side in the circumferential direction r of the yoke 3. For this reason, the overall length Lx of the entire magnet plate 5 is divided into two (Lx / 2) lengths by the first and second magnet pieces (M1, M2). The first and second magnet pieces shown as the first embodiment in comparison with the contraction length of the magnet M having the length Lx in the lateral direction x shown in FIG. The contraction length in the lateral direction x of (M1, M2) is halved and set short.

  Therefore, similarly to the first embodiment, the DC motor 1 of the second embodiment has a short length that contracts in the lateral direction x due to the temperature rise of the first and second magnets (M1, M2). Thus, the thermal stress formed on the first and second magnet pieces (M1, M2) itself and the adhesive layer is reduced more than the thermal stress formed on the magnet M shown as a conventional example in FIG. Therefore, when the magnet plate 5 is formed by the first and second magnet pieces (M1, M2), that is, two magnet pieces, the temperature of the stator 2 rises, and even when the temperature becomes high, the first In addition, the second magnet piece (M1, M2) itself is difficult to break, and the crack generated in the adhesive layer formed between the first and second magnet pieces (M1, M2) and the yoke 3 is less likely to occur. .

1 DC motor
2 Stator
3 York
3a connecting part
4 Flat plate
4a to 4f Flat plate part 5 Magnet plate
5a to 5f Magnet plate 6 Armature
7 Rotating shaft
8 Armature core
8a core body
8b Teeth
9 Armature coil
9a Winding
10 Commutator
10a Commuter piece
11 Bearing
M1 1st magnet piece
M2 Second magnet piece

Claims (4)

It has a hexagonal cylindrical shape made of a magnetic material, and has a yoke having six flat plate portions connected in series with each other, and six magnet plates formed of a sintered body mainly made of neodymium. Each of the magnet plates is attached to each inner wall of the flat plate portion formed on the yoke; and
An armature having a rotating shaft, a substantially annular core body attached to the rotating shaft, and a plurality of teeth integrally formed at equal intervals in the circumferential direction from the outer peripheral surface of the core body toward the radially outer side A core, an armature coil having a plurality of windings wound around the teeth formed on the armature core, and a plurality of commutator pieces attached to the rotating shaft in the vicinity of the armature core and having an outer peripheral surface. In a DC motor comprising a commutator and an armature that is rotatably arranged inside the stator,
The number of teeth and the number of commutator pieces are both 9,
Each of the magnet plates is formed of a first magnet piece and a second magnet piece arranged close to each other.   2. The DC motor according to claim 1, wherein the first and second magnet pieces forming the magnet plate are arranged side by side in a central axis direction of the yoke.   Of the first and second magnet pieces forming the magnet plate, the first magnet piece is deviated by a predetermined angle in one circumferential direction from the axial center line of the flat plate portion formed on the yoke. And the second magnet piece is disposed at a predetermined angle in the other circumferential direction opposite to the one circumferential direction from the axial center line of the flat plate portion formed on the yoke. The DC motor according to claim 2, wherein   2. The DC motor according to claim 1, wherein the first and second magnet pieces forming the magnet plate are arranged side by side in a circumferential direction of the yoke.

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