JP2013099111A - motor - Google Patents

Abstract

Even when a field portion is made small (the length in the axial direction is shorter than that of a laminated core), the effect of skew is reduced by non-uniform magnetic flux distribution in the field portion. Provided is a motor that can be prevented.
A motor 1 includes a field portion 20 (a first field portion 20a disposed on the upper side in the axial direction and the same shape as the first field portion 20a, and the axial direction of the first field portion 20a). And a laminated core 53 supported so as to be rotatable coaxially with the field portion 20, and includes Lm (first field portion 20a and Each axial length of the second field portion 20b) <Lc (the axial length of the laminated core 53) / 2, and la (the first field portion 20a and the second field portion 20b) The length in the axial direction from the one side end of the laminated core 53 to the one side end of the first field portion 20a and the other side end of the laminated core 53 To the other end of the second field portion 20b in the axial direction).
[Selection] Figure 8

Description

  The present invention relates to a motor technology, and more particularly to a technology for reducing cogging torque.

  Conventionally, an annularly formed field portion is disposed opposite to the inside of the field portion, and is formed by stacking magnetic plates, and is supported so as to be rotatable coaxially with the field portion in the circumferential direction. The technology of a motor having a laminated core is known. In the motor having such a configuration, since the laminated core and the field part have mutual attractive force, when the laminated core is rotated even when no current is applied, So-called cogging torque is generated.

  When the cogging torque is generated in this way, there are various problems depending on the intended use of the motor. For example, when the motor is used as a motor for driving an EGR valve, there are the following problems.

  That is, when the energization is turned off and the EGR valve is not operated, a force is applied so that the EGR valve is closed to the fully closed side by an urging force such as a spring from the viewpoint of fail-safe. In such a case, if the generated cogging torque is large, it is necessary to apply a larger biasing force that overcomes the cogging torque. However, when the EGR valve is operated with energization turned on, the urging force becomes a resistance force, and thus the output of the motor needs to be further increased. Thus, when the generated cogging torque is large, there is a problem that it is necessary to further increase the output of the motor. Furthermore, since the output torque varies depending on the valve opening of the EGR valve (by the phase of the motor), there is a problem that the control of the EGR valve becomes unstable.

  On the other hand, techniques for reducing the cogging torque are known. For example, in the techniques described in Patent Documents 1 and 2, a skew that is inclined in the circumferential direction is formed in the laminated core from one end to the other end in the axial direction. As a result, the cogging torque waveforms in the respective portions of the laminated core are mutually combined to cancel each other, and the cogging torque as the whole laminated core can be reduced. In the techniques described in Patent Documents 1 and 2, the effect of the skew is prevented from being reduced due to the magnetic flux distribution of the field part by specifying the shape of the field part.

JP-A-8-228447 JP-A-10-117469

  However, in the techniques described in Patent Documents 1 and 2, the field portion needs to have an axial length equal to or longer than that of the laminated core. In other words, when the field part is made small (for example, the axial length is shorter than the laminated core) for reasons such as reducing production costs, the magnetic field distribution in the field part becomes non-uniform. As a result, the effect due to skew is reduced, and there is a problem.

  The present invention has been made in view of such a situation, and the problem to be solved is a case where the field portion is made small (the axial length is shorter than the laminated core), An object of the present invention is to provide a motor capable of preventing the effect of skew from being reduced by making the magnetic flux distribution in the field portion uniform.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

That is, according to the first aspect of the present invention, the annularly formed field portion is disposed opposite to the inside of the field portion, and is formed by stacking magnetic plates, and is coaxial with the field portion in the circumferential direction. A laminated core supported rotatably, wherein the laminated core has a skew that is inclined in a circumferential direction from one end to the other end in the axial direction. A first field portion arranged on one side of the direction, and a second field magnet having the same shape as the first field portion and spaced apart on the other side in the axial direction of the first field portion The first field part and the second field part satisfy the following mathematical formulas (1) and (2).
Formula (1) ·· Lm (length in the axial direction of each of the first field portion and the second field portion) <Lc (length in the axial direction of the laminated core) / 2
Formula (2) ·· la (length in the axial direction between the first field part and the second field part) = 2 × lo (one side end of the laminated core to one side of the first field part) Axial length to the end and axial length from the other end of the laminated core to the other end of the second field part)

  In the present invention, a rare earth magnet is used as the field part.

  As effects of the present invention, the following effects can be obtained.

  According to the first aspect of the present invention, even when the field portion is made small (the axial length is shorter than that of the laminated core), the effect of skew is reduced by uniformizing the magnetic flux distribution of the field portion. Can be prevented.

  In claim 2, since the field portion is formed small (the axial length is shorter than that of the laminated core), even when a rare earth magnet that is generally expensive is used as the field portion, Production costs can be reduced.

The disassembled perspective view which showed the structure of the motor which concerns on one Embodiment of this invention. Side surface sectional drawing which showed the structure of a part of motor. FIG. 3 is an end view taken along line AA in FIG. 2. The perspective view which showed the structure of the laminated core. The top view which showed the structure of the core member. The graph which showed the cogging torque waveform of the core member when the magnetic flux distribution of a field part is uniform. The partially expanded view which showed the structure of the field part. The table | surface which showed the relationship between the structure of a field part, and the magnetic flux distribution of the surface of a lamination | stacking core. The graph which showed the cogging torque waveform of the core member when the magnetic flux distribution of a field part is non-uniform | heterogenous.

First, an overall configuration of a motor 1 according to an embodiment of the present invention will be briefly described with reference to FIGS.
In the following description, the front-rear direction, the left-right direction, and the up-down direction are defined based on the arrow directions shown in the drawings.

  FIG. 1 is an exploded perspective view showing a configuration of a motor 1 according to an embodiment of the present invention. FIG. 2 is a side sectional view showing a configuration of a part of the motor 1. FIG. 3 is an end view taken along line AA in FIG. FIG. 4 is a perspective view showing the configuration of the laminated core 53.

  The motor 1 shown in FIGS. 1 to 3 is a so-called DC brush motor. The motor 1 mainly includes a case 10, a field part 20, a brush holder 30, a bracket 40, and an armature 50.

  A case 10 shown in FIGS. 1 to 3 accommodates each member constituting the motor 1 and has a function as a yoke. The case 10 is formed in a substantially cylindrical shape with its cylindrical direction directed in the vertical direction. An opening 11 is formed at the upper end of the case 10. A support 12 that faces the opening 11 is formed at the lower end of the case 10. A bearing 13 is disposed inside the support portion 12.

The field part 20 shown in FIGS. 1 to 3 is formed in an annular shape by arranging a plurality of magnets 21 in the circumferential direction. A detailed description of the configuration of the field unit 20 will be given later.
The field portion 20 is an embodiment of the “field portion” in the present invention.

  A brush holder 30 shown in FIG. 1 is fitted into the opening 11 of the case 10. The brush holder 30 is formed in a substantially short cylindrical shape whose axial direction is directed in the vertical direction. Terminals 31 and 31 that are current input / output terminals are disposed on the upper side surface of the brush holder 30. The terminals 31 and 31 are electrically connected to brushes 34 and 34 disposed on the lower surface of the brush holder 30, respectively. A housing portion 32 that houses the commutator 52 is formed inside the upper center portion of the brush holder 30. An insertion hole 33 is opened in the upper center portion of the housing portion 32.

  The bracket 40 shown in FIG. 1 closes the case 10. A support portion 41 is formed at the upper center portion of the bracket 40. A bearing 42 is disposed inside the support portion 41.

  The armature 50 shown in FIG. 1 mainly includes a rotating shaft 51, a commutator 52, and a laminated core 53.

  The rotating shaft 51 shown in FIGS. 1 to 4 is arranged on the inner side of the case 10 and coaxially with the case 10 (field portion 20) with the axial direction thereof directed in the vertical direction. The lower end side of the rotating shaft 51 is rotatably supported by the bearing 13. Further, the upper end side of the rotating shaft 51 is rotatably supported by the bearing 42 through the insertion hole 33. Thus, the rotating shaft 51 is rotatably supported inside the case 10 via the bearing 13 and the bearing 42. In addition, the lower end side of the rotating shaft 51 is extended outward as an output shaft of the motor 1.

  The commutator 52 shown in FIG. 1 is formed in a substantially cylindrical shape whose axial direction is directed in the vertical direction. The commutator 52 is fixed to the rotating shaft 51 so as not to rotate relative to the rotating shaft 51, and is disposed inside the housing portion 32 of the brush holder 30. The brushes 34 and 34 of the brush holder 30 are brought into contact with the commutator 52. The electricity supplied from the outside of the motor 1 through the terminal 31 is supplied to the commutator 52 through the brush 34.

The laminated core 53 shown in FIGS. 1 to 4 is formed by stacking a plurality of core members 100 made of a magnetic plate material. The laminated core 53 is formed in a substantially cylindrical shape whose axial direction is directed in the vertical direction. The laminated core 53 is fixed to the rotary shaft 51 below the commutator 52 so as not to be relatively rotatable. Thereby, the laminated core 53 is supported so as to be rotatable around the axis (circumferential direction) via the rotation shaft 51 on the same axis as the field magnet portion 20. The laminated core 53 is disposed so as to face the inside of the field portion 20 and is disposed at the same position as the field portion 20 in the vertical direction position. A winding 65 is wound around the laminated core 53 (more specifically, a plurality of teeth 62 described later). In the drawings other than FIG. 1, the winding 65 is not shown for convenience of explanation.
The laminated core 53 is an embodiment of the “laminated core” in the present invention.

  In the above configuration, a current is supplied to the motor 1 from the outside of the motor 1 via the terminal 31. The current supplied to the terminal 31 is supplied to the commutator 52 by the brush 34 and supplied to the winding 65 wound around the laminated core 53. As a result, the armature 50 rotates around the axis of the rotating shaft 51 by the electromagnetic action with the field magnet portion 20. And the torque of the motor 1 generate | occur | produces because the rotating shaft 51 rotates around an axis | shaft.

Next, the configuration of the laminated core 53 will be described in more detail with reference to FIGS.
FIG. 5 is a plan view showing the configuration of the core member 100. FIG. 6 is a graph showing the cogging torque waveform of the core members 101, 102,... 116 when the magnetic flux distribution of the field portion 20 is uniform.

  The laminated core 53 shown in FIGS. 1 to 4 is formed by stacking a plurality of core members 100 made of a magnetic plate material as described above. The core member 100 is stacked with its plate surface directed in the same direction (vertical direction) as the axial direction of the laminated core 53. A core member 100 shown in FIG. 5 mainly includes a yoke portion 61 and a teeth portion 62.

  The yoke part 61 shown in FIG. 5 is a part located in the center part of the core member 100. The yoke portion 61 is a substantially plate-like member whose plate surface is directed in the vertical direction, and is formed in a substantially annular shape. An insertion hole 63 through which the rotating shaft 51 is inserted is opened at the center of the yoke portion 61.

  The teeth part 62 shown in FIG. 5 is a part located in the outer side part of the core member 100 (outside of the yoke part 61). The teeth part 62 is formed in a substantially T shape in plan view. The teeth part 62 is provided with a plurality (10 in this embodiment) of the same shape. The teeth portions 62, 62,... Are evenly disposed in the circumferential direction on the outer peripheral edge portion of the yoke portion 61, and extend from the outer peripheral edge portion in the longitudinal direction toward the outer radial direction. A winding 65 is wound around the teeth portions 62, 62,... (See FIG. 1).

In the present embodiment, the laminated core 53 is formed by stacking 16 core members 100. Then, the core members 100, 100,... Are in a state of rotating gradually (equally) counterclockwise in plan view as they go down one by one from the uppermost core member 100 arranged (shifting the phase). Arranged). With such a configuration, a plurality (ten in this embodiment) of skews 70, 70,... Are formed on the outer peripheral surface of the laminated core 53. The skews 70, 70,... Are formed so as to incline in the circumferential direction so that the upper side is on the left side and the lower side is on the right side, that is, from the upper end to the lower end.
The skew 70 is an embodiment of “skew” in the present invention.

  As shown in FIGS. 4 and 7, the core member 100 disposed on the uppermost side among the core members 100, 100.. 101 ”, and“ core member 102, core member 103, core member 104, core member 115, and core member 116 ”as they go downward one by one from the core member 101, respectively.

When the magnetic flux distribution of the field portion 20 is uniform, the cogging torque waveforms having different phases are generated in the core members 101, 102, 116 by forming the skews 70, 70,. . More specifically, the core member 101 and the core member 109, the core member 102 and the core member 110,..., And the core member 109 and the core member 116 generate cogging torque waveforms that have opposite phases and the same amplitude. To do. Then, these cogging torque waveforms with shifted phases cancel each other out, and the cogging torque is reduced as a whole of the core members 101, 102, 116 (laminated core 53). In the present embodiment, as described above, the cogging torque waveforms of the upper half and the lower half of the laminated core 53 (that is, the core members 101 to 108 and the core members 109 to 116) are combined with each other. Is configured to cancel each other out.
Thus, by forming the skews 70, 70,... In the laminated core 53, the cogging torque can be reduced.

Next, the configuration of the field magnet portion 20 will be described in detail with reference to FIG.
FIG. 7 is a partially enlarged view showing the configuration of the field magnet portion 20.

  As described above, the field portion 20 is formed in an annular shape by arranging a plurality of magnets 21 in the circumferential direction. In the present embodiment, a rare earth magnet is used as the magnet 21. The field part 20 includes a first field part 20a and a second field part 20b.

  The first field portion 20a is formed in an annular shape by arranging a plurality of magnets 21a in the circumferential direction. The magnet 21 a is formed in a substantially curved plate shape with its plate surface directed in the inner diameter direction and the outer diameter direction in the case 10. A plurality (four in this embodiment) of magnets 21a having the same shape are provided. The magnets 21a, 21a,... Are fixed to the inner peripheral surface of the case 10. The magnets 21a, 21a,... Are equally arranged in the circumferential direction, and are formed in a substantially cylindrical shape as a whole with the cylinder center (axis) direction directed in the vertical direction. The upper end portion of the first field portion 20 a is formed below the upper end portion of the laminated core 53.

  The second field portion 20b has the same shape as the first field portion 20a, and is spaced apart from the lower side in the axial direction of the first field portion 20a.

  More specifically, the second field portion 20b is formed in an annular shape by arranging a plurality of magnets 21b having the same shape as the magnet 21a in the circumferential direction. The magnet 21b is formed in a substantially curved plate shape with its plate surface facing the inner diameter direction and the outer diameter direction in the case 10. A plurality of magnets 21b having the same shape (four in this embodiment) are provided. The magnets 21b, 21b,... Are fixed to the inner peripheral surface of the case 10. The magnets 21b, 21b,... Are evenly arranged in the circumferential direction, and are formed in a substantially cylindrical shape as a whole with the cylinder center direction directed in the vertical direction. The lower end portion of the second field portion 20 b is formed above the lower end portion of the laminated core 53.

  Thus, the field portion 20 (the first field portion 20a and the second field portion 20b) has an axial length (from the upper end of the first field portion 20a to the bottom of the second field portion 20b). The length to the side end) is shorter than the axial length of the laminated core 53 (the length from the upper end to the lower end of the laminated core 53).

  And the 1st field part 20a and the 2nd field part 20b are formed so that the following numerical formula (1) and numerical formula (2) may be satisfy | filled.

(Equation 1)
Lm <Lc / 2

  Here, “Lm” refers to the axial length of each of the first field portion 20a and the second field portion 20b. The “Lc” refers to the axial length of the laminated core 53.

(Equation 2)
la = 2 × lo

  Here, “la” refers to the length in the axial direction between the first field portion 20a and the second field portion 20b. The “lo” is the axial length from the upper end (one side end) of the laminated core 53 to the upper end (one side end) of the first field part 20 a, and the laminated core 53. This refers to the length in the axial direction from the lower end (other end) of the second field portion 20b to the lower end (other end).

Below, the effect produced when the 1st field part 20a and the 2nd field part 20b satisfy | fill said numerical formula (1) and numerical formula (2) is demonstrated using FIG.8 and FIG.9.
FIG. 8 is a table showing the relationship between the configuration of the field unit 20 and the conventional field unit 120 and the magnetic flux distribution on the surface of the laminated core 53. FIG. 9 is a graph showing the cogging torque waveform of the core members 101, 102, .. 116 when the magnetic flux distribution of the field portion 20 (the first field portion 20a and the second field portion 20b) is not uniform. It is.

  As shown in FIG. 8, according to the configuration of the conventional field portion 120 (configuration that does not satisfy the above formulas (1) and (2)), the magnetic flux density on the surface of the laminated core 53 is The upper half and the lower half of 53 do not match at corresponding locations. Here, the “corresponding portion between the upper half and the lower half of the laminated core 53” means that if the magnetic field distribution of the field portion 120 is uniform, they are canceled by being combined with each other. This is a point where a cogging torque waveform is generated. Therefore, in such a case, the cogging torque waveforms change at the corresponding portions of the upper half and the lower half of the laminated core 53, so that the phases are opposite to each other and the amplitudes do not coincide with each other. As a result, the effect of the skew 70, 70,... Is reduced by the magnetic flux distribution of the field part 120 (cogging torque cannot be reduced).

  On the other hand, as shown in FIG. 8, the configuration of the field portion 20 (the first field portion 20a and the second field portion 20b) (a configuration that satisfies the above formulas (1) and (2)). According to the above, the magnetic flux density on the surface of the laminated core 53 is the same in the corresponding portions of the upper half and the lower half of the laminated core 53. Therefore, in such a case, even if the cogging torque waveform changes in the corresponding portions of the upper half and the lower half of the laminated core 53, as shown in FIG. A matching relationship is maintained. As a result, it is possible to prevent the effects due to the skews 70, 70,. be able to).

As described above, the motor 1 according to one embodiment of the present invention is
A field portion 20 formed in an annular shape;
A laminated core 53 that is disposed facing the inside of the field portion 20 and is formed by stacking core members 100 (magnetic plate materials), and is supported so as to be rotatable coaxially with the field portion 20 in the circumferential direction;
Comprising
The laminated core 53 is a motor in which skews 70, 70,... That are inclined in the circumferential direction from one end to the other end in the axial direction are formed,
The field part 20 has the same shape as the first field part 20a and the first field part 20a arranged on the upper side (one side) in the axial direction, and the axial direction of the first field part 20a. A second field portion 20b that is spaced apart from the lower side (the other side) of
The first field part 20a and the second field part 20b satisfy the following formulas (1) and (2).
Formula (1) ·· Lm (length in the axial direction of each of the first field portion 20a and the second field portion 20b) <Lc (length in the axial direction of the laminated core 53) / 2
Formula (2) ·· la (length in the axial direction between the first field portion 20a and the second field portion 20b) = 2 × lo (from one end of the laminated core 53 to the first field portion) The length in the axial direction to one end of 20a and the length in the axial direction from the other end of the laminated core 53 to the other end of the second field portion 20b)

  With such a configuration, even when the field portion 20 (the first field portion 20a and the second field portion 20b) is formed small (the axial length is shorter than the laminated core 53), By making the magnetic flux distribution of the field part 20 (the first field part 20a and the second field part 20b) uniform, it is possible to prevent the effects due to the skews 70, 70,. As a result, the field portion 20 can be formed small, and the production cost can be suppressed.

  Further, a rare earth magnet is used as the field part 20.

  With this configuration, the field portion 20 (the first field portion 20a and the second field portion 20b) is formed to be small (the axial length is shorter than that of the laminated core 53). Even if rare earth magnets that are generally expensive are used as the (first field part 20a and second field part 20b), the production cost can be suppressed.

1 motor 20 field part 20a first field part 20b second field part 53 laminated core 70 skew

Claims (2)

A field part formed in an annular shape;
A laminated core that is arranged facing the inside of the field part, is formed by stacking magnetic plates, and is supported so as to be rotatable coaxially with the field part in the circumferential direction;
Comprising
The laminated core is a motor in which a skew that is inclined in the circumferential direction from one end to the other end in the axial direction is formed,
The field portion has a first field portion disposed on one side in the axial direction and the same shape as the first field portion and is spaced apart from the other side in the axial direction of the first field portion. A second field portion to be disposed,
The first field part and the second field part satisfy the following mathematical formulas (1) and (2):
A motor characterized by that.
Formula (1) ·· Lm (length in the axial direction of each of the first field portion and the second field portion) <Lc (length in the axial direction of the laminated core) / 2
Formula (2) ·· la (length in the axial direction between the first field part and the second field part) = 2 × lo (one side end of the laminated core to one side of the first field part) Axial length to the end and axial length from the other end of the laminated core to the other end of the second field part) Using a rare earth magnet as the field part,
The motor according to claim 1.

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