Technical Field
5 [0001] The present invention relates to an electric
motor including a main body including an opening at an
end thereof, and a bracket attached to the main body so
as to cover the opening.
Background Art
10 [0002] As an electric motor, an inner-rotor electric
motor has been conventionally known, in which a
columnar rotor including a permanent magnet portion is
disposed coaxially with a cylindrical stator, which
generates a rotating magnetic field, on the inner
15 diameter side of the cylindrical stator. This electric
motor is, for example, used to rotationally drive a
blower fan mounted in an air conditioner.
[0003] This type of electric motor includes an
electric motor including leg portions for attaching the
20 electric motor to a target object, to which the
electric motor is to be fixed. The leg portions are
formed to protrude from the outer circumferential
surface of the main body of the electric motor in an
outer diameter direction and formed close to an end of
25 the electric motor in a rotation axis direction (see,
e.g., Patent Literature 1).
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Citation List
Patent Literature
[0004] Patent Literature 1: Japanese Patent
Application Laid-open No. 2015-274604
5 Disclosure of Invention
Technical Problem
[0005] Here, in order to prevent the transmission of
vibration to a target object to which the electric
motor is to be fixed (e.g., casing of air conditioner),
10 it is conceivable that a vibrationproof member is
attached to the leg portion to fix the electric motor
to the target object via the vibrationproof member.
However, if a thick vibrationproof member is disposed
at the leg portion of the electric motor of Patent
15 Literature 1, the vibrationproof member largely
protrudes from the shell of the electric motor in the
rotation axis direction, which results in a problem
that the electric motor and the target object, to which
the electric motor is fixed, are distant from each
20 other. On the other hand, if the thickness of the
vibrationproof member in the rotation axis direction is
reduced to suppress the protrusion in the rotation axis
direction, the vibrationproof performance by the
vibrationproof member is probably reduced.
25 [0006] In this regard, it is an object of the
present invention to provide an electric motor capable
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of ensuring vibrationproof performance while
suppressing the height of a vibrationproof member
protruding in a rotation axis direction from the shell
of the electric motor when the vibrationproof member is
5 disposed in this type of electric motor.
Solution to Problem
[0007] According to an aspect of the present
invention, there is provided an electric motor
including: a rotor; a shaft disposed along a rotation
10 axis of the rotor; a main body having a bottomed
cylindrical shape having an opening on one end side in
an axis direction of the rotation axis; and a bracket
that covers the opening of the main body, the rotor
being stored in an internal space covered with the main
15 body and the bracket.
The main body includes leg portions extending
outward in a radial direction on the one end side of
the main body. The bracket includes a circular plate
portion and protrusions protruding outward in the
20 radial direction from the circular plate portion.
The leg portion includes a leg-portion-side
fastening portion to which the protrusion of the
bracket is to be fastened, and a vibrationproof member
placing portion in which a vibrationproof member is to
25 be disposed. The vibrationproof member placing portion
of the leg portion is disposed in a manner that does
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not overlap with the protrusion of the bracket in the
axis direction.
[0008] According to the present invention, it is
possible to ensure vibrationproof performance while
5 suppressing the height of a vibrationproof member
protruding in a rotation axis direction from the shell
of an electric motor.
Brief Description of Drawings
[0009] [Fig. 1] Fig. 1 is an overall perspective
10 view of a permanent magnet electric motor according to
the present invention.
[Fig. 2] Fig. 2 is a transverse cross-sectional view
of the permanent magnet electric motor according to the
present invention.
15 [Fig. 3] Fig. 3 is a perspective view of a bracket of
the permanent magnet electric motor according to the
present invention.
[Fig. 4] Fig. 4 is an overall perspective view of the
permanent magnet electric motor according to the
20 present invention, showing a state in which the bracket
of Fig. 3 is removed.
[Fig. 5] Fig. 5 is a cross-sectional view of a crosssection
taken along a slitted groove shown in Fig. 1.
[Fig. 6] Fig. 6 is an overall perspective view of the
25 electric motor according to the present invention as
viewed from an output side, showing a state in which a
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vibrationproof member is removed.
[Fig. 7] Fig. 7 is a perspective view showing a state
in which the vibrationproof member is attached in Fig.
6.
5 [Fig. 8] (A) is a schematic view showing a state in
which the permanent magnet electric motor of an
embodiment is attached to a target object, and (B) is a
schematic view showing a state in which an electric
motor of a comparative example is attached to a target
10 object.
Mode(s) for Carrying Out the Invention
[0010] Next, an embodiment of the present invention
will be described with reference to the drawings. In
the following description about the drawings, the same
15 or similar portions will be denoted by the same or
similar reference symbols. It should be noted that the
drawings are schematic and may differ from reality.
Therefore, specific constituent parts should be
determined by referring to the following description.
20 [0011] Further, the embodiment to be described below
exemplifies apparatuses and methods for embodying the
technical idea of the present invention, and the
technical idea of the present invention does not
specify the shape, structure, arrangement, and the like
25 of the constituent parts to those described below.
Various modifications can be made to the technical idea
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of the present invention within the technical scope
defined by the claims.
[0012] Hereinafter, an electric motor according to
an embodiment of the present invention will be
5 described.
[0013]
Figs. 1 to 5 are views for describing a
configuration of an electric motor 1 of this embodiment.
As shown in those figures, this permanent magnet
10 electric motor 1 is a brushless DC motor, for example.
The electric motor 1 is, for example, used to
rotationally drive a blower fan mounted in an outdoor
unit of an air conditioner, though not shown in the
figures.
15 [0014] As shown in Figs. 1 and 2, the permanent
magnet electric motor 1 of this embodiment includes a
stator 2, a rotor 3, a motor shell (casing, main body)
10, and a bracket 41.
Hereinafter, an inner-rotor permanent magnet
20 electric motor 1 will be described as an example, in
which a columnar rotor 3 including a permanent magnet
portion 31 is rotatably disposed inward in the radial
direction of a cylindrical stator 2 that generates a
rotating magnetic field.
25 [0015]
As shown in Fig. 2, the rotor 3 includes an
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annular permanent magnet portion 31 and a coupling
portion 35, which is disposed on the inner diameter
side relative to the permanent magnet portion 31 and
couples the permanent magnet portion 31 and a shaft 32
5 to each other. The shaft 32 is disposed along the
center axis of the columnar rotor 3 and also fixed to
the rotor 3. In this embodiment, the permanent magnet
portion 31 and the coupling portion 35 of the rotor 3
are formed by integral molding of a resin material in
10 which a ferrite magnetic substance is mixed. After the
molding, only the permanent magnet portion 31 is
magnetized to cause the permanent magnet portion 31 to
function as a ferrite bonded magnet. Further, the
permanent magnet portion 31 is magnetized to be a polar
15 anisotropic magnet in which a south pole and a north
pole alternately appear in the circumferential
direction thereof. Thus, a part of a yoke for
concentrating the flow of the magnetic flux of the
permanent magnet portion 31 becomes unnecessary, and
20 the leakage flux can be suppressed.
Note that the permanent magnet portion 31 and the
coupling portion 35 may be formed separately. For
example, the rotor 3 may be a so-called surface magnet
(SPM) rotor, in which a plurality of ferrite sintered
25 magnets (corresponding to the permanent magnet portion
31), which are obtained by sintering a powder-like
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ferrite magnetic substance in a mold, are annularly
attached to the outer circumferential surface of a
rotor core (corresponding to the coupling portion 35).
[0016] The stator 2 includes a stator core 21
5 including a cylindrical yoke portion (not shown) and a
plurality of teeth portions (not shown) extending from
the yoke portion to the inner diameter side, and
winding (not shown) wound around the teeth portions via
an insulator. The stator 2 is covered with the motor
10 shell 10 (main body) formed of resin by resin integral
molding, except for the inner circumferential surface
of the stator core 21 (see Figs. 2 and 4). Specifically,
the motor shell 10 covers the stator 2 including the
stator core 21 and the winding. As shown in Figs. 1 and
15 2, the stator 2 is disposed on the outer
circumferential side of the rotor 3 (outward in the
radial direction of the permanent magnet electric motor
1). Further, the stator core 21 of the stator 2 is
disposed such that the teeth portions of the stator
20 core 21 face the permanent magnet portion 31 of the
rotor 3 in the radial direction. In other words, the
stator 2 is disposed such that the annular permanent
magnet portion 31 of the rotor 3 faces the stator core
21 of the stator 2 in the radial direction.
25 [0017] As shown in Fig. 4, the motor shell 10 as a
main body is formed into a bottomed cylindrical shape
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having an opening O on one side (in the embodiment, the
opposite output side of the shaft 32) in the axis
direction of the center axis of the permanent magnet
electric motor 1, that is, the rotation axis of the
5 rotor 3 (hereinafter, rotation axis C). In this
embodiment, the motor shell 10 includes an annular
portion 12, the opening O, and an end surface portion
(bottom surface) 13 formed at the end portion on the
opposite side of the opening O (the output side of the
10 shaft 32). The rotor 3 is stored in the internal space
covered with the motor shell (main body) 10 and the
bracket 41 (see Figs. 2 and 4).
[0018] The rotor 3 is rotatably disposed on the
inner circumferential side of the stator core 21 of the
15 stator 2 with a predetermined clearance (gap) from the
stator core 21. As shown in Figs. 2, 4, and 5, the
permanent magnet portion 31 disposed in an annular
shape is disposed on the outer side (outer
circumference side) in the radial direction of the
20 rotor 3 so as to face the stator core 21.
[0019] The rotor 3 is fixed to the circumference of
the shaft 32. The shaft 32 is rotatably supported
(held) by a first bearing 33 and a second bearing 34
fixed to the outer circumferential surface of the shaft
25 32. Further, the first bearing 33 is stored (held) in a
first bearing storing portion 42 to be described later,
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and the second bearing 34 is stored (held) in a second
bearing storing portion 43 to be described later, so
that the rotor 3 is rotatably supported. The first
bearing storing portion 42 and the second bearing
5 storing portion 43 are formed of, for example, a
magnetic substance of chromium-nickel-based stainless
steel.
[0020]
As shown in Figs. 2, 3, and 5, the first bearing
10 33 is fixed to one end side (opposite output side) of
the shaft 32 at the inner race side of the first
bearing 33. The second bearing 34 is fixed to the other
end side (output side) of the shaft 32 at the inner
race side of the second bearing 34. The first bearing
15 33 and the second bearing 34 (a pair of bearings)
cooperate to rotatably support the shaft 32 and the
rotor 3 coupled to the shaft 32. For example, a ball
bearing is used for each of the first bearing 33 and
the second bearing 34.
20 [0021] The bracket 41 includes the first bearing
storing portion 42 that is formed of a magnetic
substance and stores the first bearing 33, and a nonmagnetic
portion 44 (end surface portion) formed of a
non-magnetic substance (e.g., resin). In the motor
25 shell 10 (main body) of the permanent magnet electric
motor 1, the bracket 41 is disposed at an end in the
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rotation axis C direction, that is, disposed on the
opposite output side of the shaft 32. The non-magnetic
portion (end surface portion) 44 of the bracket 41
includes a connection portion 45 connected to the first
5 bearing storing portion 42 (see Figs. 2, 3, and 5). The
non-magnetic portion (end surface portion) 44 of the
bracket 41 is integrally formed with the first bearing
storing portion 42, which is a magnetic portion, by
insert molding. The non-magnetic portion (end surface
10 portion) 44 is connected to the first bearing storing
portion 42 at the connection portion 45.
The bracket 41 is attached to the end portion of
the motor shell 10 (main body) on the opposite output
side by using screws to serve as a lid for covering the
15 opening O of the motor shell 10 (main body). Note that
the opening O of the motor shell 10 (main body) may be
provided toward the output side. In this case, the
bracket 41 is disposed not on the opposite output side
of the shaft 32 but on the output side of the shaft 32.
20 [0022] The non-magnetic portion 44 (end surface
portion) of the bracket 41 includes a circular plate
portion 414 formed into a substantially circular plate
shape having the outer shape in the radial direction,
which expands to the outer circumferential surface of
25 the motor shell 10 in the radial direction. Further,
the non-magnetic portion 44 (end surface portion) of
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the bracket 41 forms a resin shell of the permanent
magnet electric motor 1 together with the motor shell
10. Additionally, the non-magnetic portion 44 includes
protrusions 410, which protrude from the circular plate
5 portion 414 outward in the radial direction relative to
the outer circumferential surface of the motor shell 10
as viewed from the rotation axis C direction. The
protrusions 410 each abut on the basal end portion of a
leg portion 107 of the motor shell 10. The leg portion
10 107 will be described later. The protrusion 410 of the
bracket 41 is disposed so as to overlap with the leg
portion 107 in the rotation axis C direction.
[0023] The protrusions 410 of the bracket 41 are
formed as many as the leg portions 107 provided to the
15 motor shell 10 (three positions). For example, the
protrusions 410 are each formed into a trapezoidal
shape as viewed from the rotation axis C direction and
each include, at the center portion thereof, a screw
through hole 413 penetrating in the rotation axis C
20 direction.
[0024] Note that the bracket 41 includes a slitted
groove 416 for providing an electrically conductive
member 5 for measures against electrolytic corrosion,
which will be described later, on the outer surface
25 side exposed to the outside in the permanent magnet
electric motor 1 after assembling (see Figs. 1 and 3).
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The slitted groove 416 extends outward in the
radial direction from the center portion of the bracket
41 (tubular connection portion 45 of the non-magnetic
portion 44 to be described later) to the outer
5 circumferential surface of the bracket 41, and further
extends in the axis direction from there to the
position abutting on the motor shell 10.
[0025] The bracket 41 is fitted into the motor shell
10 (main body) and then screwed at leg-portion-side
10 fastening portions (screw holes) 103 (to be described
later) of the leg portions 107 of the motor shell 10
via the screw through holes 413 (see Fig. 1).
Further, the first bearing storing portion
(bearing house portion) 42 for storing the first
15 bearing 33 on the inner side (output side) of the
permanent magnet electric motor 1 is disposed at the
center portion of the circular plate shape bracket 41.
The first bearing storing portion 42 is formed into,
for example, a substantially bottomed cylindrical shape
20 by press working. Further, the non-magnetic portion 44
of the bracket 41 includes, at the inner diameter side
thereof, the tubular connection portion 45 connected to
the first bearing storing portion 42 (see Figs. 2 and
5).
25 [0026] The second bearing storing portion (bearing
house portion) 43 for storing the second bearing 34 on
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the inner side (opposite output side) of the electric
motor 1 is disposed at the center portion of the output
side end portion of the motor shell 10 (see Figs. 2, 5,
and 6). The second bearing storing portion 43 is formed
5 into, for example, a substantially bottomed cylindrical
shape similarly to the first bearing storing portion 42.
The second bearing storing portion 43 is disposed
inward (inner diameter side) relative to the annular
permanent magnet portion 31 in the radial direction of
10 the rotor 3. The end surface portion 13 of the motor
shell 10 includes a connection portion 14 that is
connected to a flange portion 432 (to be described
later) of the second bearing storing portion 43.
[0027] As shown in Figs. 2 and 5, the first bearing
15 storing portion 42 includes a tubular portion 421 that
holds the outer race side of the first bearing 33 from
the radial direction, an annular flange portion 422
that extends outward (outer circumferential side) in
the radial direction of the rotor 3 from one end
20 portion of the tubular portion 421 in the rotation axis
C direction, and a coronal portion 423 that extends
inward (inner circumferential side) in the radial
direction from the other end portion of the tubular
portion 421 in the rotation axis C direction. The
25 coronal portion 423 covers the other end side of the
first bearing 33 in the rotation axis C direction. The
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outer circumferential edge of the annular flange
portion 422 is located inward (inner circumferential
side) in the radial direction of the rotor 3 relative
to the permanent magnet portion 31. In other words, the
5 first bearing storing portion 42 is formed so as not to
overlap with the permanent magnet portion 31 as viewed
from the rotation axis C direction of the rotor 3.
[0028] Specifically, the first bearing storing
portion 42 (bearing house portion of the bracket 41 is
10 disposed inward (inner diameter side) in the radial
direction of the rotor 3 relative to the permanent
magnet portion 31, as viewed from the rotation axis C
direction. Further, the outer circumferential edge
portion (edge portion on the outer diameter side) of
15 the flange portion 422 of the first bearing storing
portion 42 (bearing house portion) is covered with
resin that is a non-magnetic substance. Specifically,
in the bracket 41, the outer circumferential edge
portion of the flange portion 422 of the first bearing
20 storing portion 42 is covered with the non-magnetic
portion 44 made of resin.
[0029] As described above, the bracket 41 is formed
by the first bearing storing portion (magnetic portion)
42, which is one of the pair of bearing storing
25 portions (bearing house portions), and the non-magnetic
portion 44 (end surface portion). The first bearing
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storing portion (magnetic portion) 42 is disposed on
the inner diameter side relative to the permanent
magnet portion 31 in the radial direction of the rotor
3, and thus can prevent the flange portion 422 of the
5 first bearing storing portion 42 serving as a magnetic
portion from facing the permanent magnet portion 31 in
the rotation axis C direction. This makes it possible
to suppress a leakage flux flowing from the permanent
magnet portion 31 to the first bearing storing portion
10 (magnetic portion) 42. Furthermore, in the first
bearing storing portion (magnetic portion) 42, the
outer circumferential edge portion of the flange
portion 422, which is disposed close to the permanent
magnet portion 31 of the rotor 3, is covered with the
15 non-magnetic portion 44. This makes it possible to
block the path of the leakage flux flowing from the
permanent magnet portion 31 to the first bearing
storing portion (bearing house portion) 42 formed of a
magnetic substance by the non-magnetic portion 44
20 formed of a non-magnetic substance, and thus further
possible to suppress the leakage flux flowing from the
permanent magnet portion 31 to the first bearing
storing portion 42.
[0030] Note that such a structure for suppressing
25 the leakage flux can be applied to not only the first
bearing storing portion 42 side but also the second
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bearing storing portion 43 side. At that time, the
second bearing storing portion 43 is formed into the
shape similar to that of the first bearing storing
portion 42 and includes a tubular portion 431 that
5 holds the outer race side of the second bearing 34 from
the radial direction, an annular flange portion 432
that extends outward in the radial direction of the
rotor 3 from one end portion of the tubular portion 431
in the rotation axis C direction, and a coronal portion
10 433 that extends inward in the radial direction from
the other end portion of the tubular portion 431 in the
rotation axis C direction. Additionally, the second
bearing storing portion 43 is disposed on the inner
diameter side relative to the permanent magnet portion
15 31 in the radial direction of the rotor 3. Further, the
outer circumferential edge portion of the flange
portion 422 of the second bearing storing portion 43 is
covered with the end surface portion 13 (connection
portion 14) of the resin motor shell 10 that is a non20
magnetic substance. This makes it possible to suppress
the leakage flux flowing from the permanent magnet 31
to the second bearing storing portion 43.
[0031] The non-magnetic portion (end surface
portion) 44 of the bracket 41 includes the connection
25 portion 45 connected to the first bearing storing
portion (bearing house portion) 42. The connection
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portion 45 is formed into a substantially tubular shape,
and the flange portion 422 of the first bearing storing
portion (bearing house portion) 42 is inserted into and
fixed to the side surface of the tubular connection
5 portion 45 on the inner diameter side. Here, the
tubular portion 421 of the first bearing storing
portion 42 is not in contact with the non-magnetic
portion 44 of the bracket 41 (is not covered with the
non-magnetic portion 44), and only the outer
10 circumferential edge portion of the flange portion 422
is joined (connected) to the connection portion 45 of
the non-magnetic portion 44 so as to be covered
therewith. Further, a clearance portion (air gap) AG1
is formed between the tubular portion 421 of the first
15 bearing storing portion 42 and the tubular connection
portion 45 of the non-magnetic portion 44. With this
configuration, the deformation of the motor shell 10
due to heat, shock, or the like hardly affects the
first bearing 33. Furthermore, the contact area between
20 the connection portion 45 of the bracket 41 and the
flange portion 422 of the first bearing storing portion
42 can be reduced, and thus the heat generated at the
winding wound in the stator core 21 can be prevented
from being transmitted to the first bearing 33 via the
25 bracket 41. This makes it possible to suppress an
increase in temperature of the first bearing 33 and
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prevent the first bearing 33 from deteriorating.
[0032] In this embodiment, the second bearing
storing portion 43, which is the other one of the pair
of bearing storing portions (bearing house portions),
5 also has the structure similar to that of the first
bearing storing portion 42. Specifically, the motor
shell 10 is formed into a bottomed cylindrical shape
and includes the annular portion 12 of the motor shell
10, which is integrally formed with the stator 2, and
10 the end surface portion 13 of the motor shell 10, which
is connected to the end portion of the annular portion
12 and expands inward (inner circumferential side) in
the radial direction. Additionally, the end surface
portion 13 of the motor shell 10 includes the
15 cylindrical connection portion 14 connected to the
second bearing storing portion 43. Further, similarly
to the first bearing storing portion 42, the second
bearing storing portion 43, which is the other one of
the pair of bearing storing portions, includes the
20 tubular portion 431 and the flange portion 432
extending outward in the radial direction from the
tubular portion 431, and only the outer circumferential
edge portion of the flange portion 432 is inserted into
and fixed to the side surface of the connection portion
25 14 of the resin shell (motor shell 10) on the inner
diameter side. Further, a clearance portion (air gap)
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AG2 is formed between the tubular portion 431 of the
second bearing storing portion 43 and the connection
portion 14 of the resin shell (motor shell 10).
With this configuration, the deformation of the
5 motor shell 10 due to heat, shock, or the like hardly
affects the second bearing 34. Furthermore, the contact
area between the connection portion 14 of the motor
shell 10 and the flange portion 432 of the second
bearing storing portion 43 can be reduced, and thus the
10 heat generated at the winding wound in the stator core
21 can be prevented from being transmitted to the
second bearing 34 via the resin shell 10. This makes it
possible to suppress an increase in temperature of the
first bearing 33 and prevent the first bearing 33 from
15 deteriorating.
[0033] Further, as described above, the rotor 3
includes the coupling portion 35, to which the shaft 32
is fixed and which couples the permanent magnet portion
31 and the shaft 32 to each other. The permanent magnet
20 portion 31 is disposed so as to face the cylindrical
stator core 21 in the radial direction. The coupling
portion 35 is disposed on the inner diameter side of
the permanent magnet portion 31 annularly disposed. As
shown in Figs. 2 and 4, the coupling portion 35
25 includes a recess 36 that is recessed toward the center
of the coupling portion 35 in the axis direction of the
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rotation axis C (rotation axis C direction). The recess
36 is formed such that the thickness of the coupling
portion 35 in the rotation axis C direction at the
position at which the recess 36 is formed is smaller
5 than the thickness of the permanent magnet portion 31
in the rotation axis C direction. Additionally, the
flange portion 422 of the first bearing storing portion
42 is disposed so as to overlap with the recess 36 in
the rotation axis C direction. This makes it possible
10 to form the annular recess 36 recessed toward the
rotation axis C direction in the rotor 3, so that the
flange portion 422 of the first bearing storing portion
42 can be disposed within the recess 36.
In such a manner, a part of the first bearing
15 storing portion 42 (flange portion 422) can enter the
annular recess 36 recessed in the axis direction of the
rotation axis C, thus reducing the thickness of the
permanent magnet electric motor 1 in the rotation axis
C direction and downsizing the permanent magnet
20 electric motor 1 in the rotation axis C direction.
[0034] As shown in Fig. 4, terminal pins 26
electrically connected to the winding (not shown) of
the stator core 21, and bosses 27 each serving as a
guide used when a substrate (not shown) is attached are
25 provided at the end portion (upper end portion in Fig.
4) of the stator 2 on the opposite output side in the
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rotation axis C direction.
The bracket 41 functions as an insulation cover
for preventing the terminal pins 26 from being exposed
to the outside of the permanent magnet electric motor 1.
5 In this embodiment, the terminal pins 26 are
provided at three positions, and the bracket 41 is
attached to the motor shell 10 so as to cover up those
three positions.
[0035] The bracket 41 includes the cover main body
10 (circular plate portion) 414 to be attached along the
upper end surface of the stator 2 and a fitting portion
415 integrally formed with the cover main body
(circular plate portion) 414. The cover main body
(circular plate portion) 414 and the fitting portion
15 415 correspond to the non-magnetic portion 44 (end
surface portion).
The cover main body 414 is formed into a
substantially circular plate shape as a whole. As shown
in Fig. 3, the fitting portion 415 is formed as an
20 annular protrusion disposed at the outer
circumferential edge portion of the cover main body
(circular plate portion) 414. The fitting portion 415
is fitted into the end portion of the motor shell 10 on
the opposite output side (upper end surface of the
25 motor shell 10 in Fig. 4) from the rotation axis C
direction, so that the motor shell 10 (main body) and
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the bracket 41 are aligned with each other, and the
first bearing 33 is stored in the first bearing storing
portion 42 of the bracket 41 as shown in Fig. 2.
[0036]
5 The motor shell 10 (main body) includes the
plurality of leg portions 107 extending so as to
protrude outward (outer diameter side) in the radial
direction, on one end side in the rotation axis C
direction (the side on which the opening O is provided;
10 in the embodiment, an end portion on the opposite
output side) (see Figs. 1, 2, and 4 to 7). Three leg
portions 107 are arranged at regular intervals in the
circumferential direction of the permanent magnet
electric motor 1, for example.
15 The plurality of leg portions 107 each protrude
into a trapezoidal shape in the outer diameter
direction of the stator 2 (permanent magnet electric
motor 1) and each have a predetermined thickness in the
rotation axis C direction. Note that any number of leg
20 portions 107, such as two or six leg portions 107, may
be provided, and the plurality of leg portions 107 need
not be arranged at regular intervals.
[0037] As shown in Figs. 1, 4, and 7, each leg
portion 107 is formed such that the length of the leg
25 portion 107 in the circumferential direction becomes
shorter outward (outer diameter side) in the radial
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direction of the permanent magnet electric motor 1.
This makes it possible to ensure the strength of the
leg portion 107 and also effectively use a dead space
formed in the leg portion 107. The dead space will be
5 described later.
Each leg portion 107 includes a vibrationproof
member placing portion 104 in which a vibrationproof
member 6 is to be disposed. In this embodiment, the
vibrationproof member placing portion 104 is formed as
10 a cutout portion for fitting the vibrationproof member
6 thereinto from the outside (outer circumferential
side) in the radial direction of the permanent magnet
electric motor 1 to the inner diameter direction. The
vibrationproof member placing portion (cutout portion)
15 104 formed in each leg portion 107 is formed at the
center of the leg portion 107 in the circumferential
direction of the permanent magnet electric motor 1. The
vibrationproof member placing portion (cutout portion)
104 is formed by cutting out the outer diameter side of
20 the leg portion 107 so as to connect a hole formed in
each leg portion 107 to penetrate in the rotation axis
C direction and the outer circumferential edge of the
leg portion 107 to each other. Note that the
vibrationproof member placing portion 104 need not be a
25 cutout portion connected to the outer circumferential
edge of the leg portion 107 and may be a mere through
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hole penetrating in the rotation axis C direction. In
this case, the vibrationproof member 6 is inserted into
the vibrationproof member placing portion 104, which is
formed as a through hole, in the rotation axis C
5 direction.
Further, the vibrationproof member placing portion
104 provided to the leg portion 107 includes a recess
portion 106 recessed on one side of the leg portion 107
in the rotation axis C direction (the output side of
10 the shaft 32) along with the shape of the
vibrationproof member 6 to be described later.
[0038] Examples of the vibrationproof member 6
include vibrationproof rubbers and bushings, each of
which is molded into a hollow bobbin shape or a
15 cylindrical shape. The vibrationproof member 6 of the
embodiment is formed into a bobbin shape and includes a
central core portion 61, flange portions 62 formed at
both ends of the central core portion 61 in the
rotation axis C direction, and an insertion hole 63
20 into which a fastening member is to be inserted (see
Figs. 5 and 7). Note that the bobbin-shaped
vibrationproof member 6 may have a hexagonal shape or a
square shape as viewed from the rotation axis C
direction (as viewed from the top). A fastening member
25 (e.g., screw) for attaching the permanent magnet
electric motor 1 to a target object (e.g., casing of
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air conditioner), to which the permanent magnet
electric motor 1 is to be fixed, is inserted into the
insertion hole 63 of the vibrationproof member 6 in the
rotation axis C direction. The vibrationproof member 6
5 is formed of an elastic material such as ethylene
propylene diene rubber (EPDM) or chloroprene rubber
(CR).
[0039] The leg-portion-side fastening portion 103 is,
for example, a screw hole or an embedded nut, to which
10 a fastening member (screw or the like) (not shown) is
to be fastened. The leg-portion-side fastening portion
103 formed in the leg portion 107 and the screw through
hole 413 formed in the bracket 41 are fastened via a
fastening member, and thus the leg-portion-side
15 fastening portion 103 is disposed in a manner that does
not overlap with the vibrationproof member 6. This
makes it possible to effectively use the region in each
leg portion 107 where the vibrationproof member 6 is
not disposed (dead space), and to thus suppress an
20 increase in size of each leg portion 107.
[0040] Fig. 8A is a schematic view of the permanent
magnet electric motor 1 and the vibrationproof member 6
of the embodiment. As shown in Fig. 7 and 8A, the
vibrationproof member 6 is formed such that a height Hf
25 of the flange portion 62 in the rotation axis C
direction of the permanent magnet electric motor 1 is
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higher than a thickness Hb of the bracket 41 in the
rotation axis C direction. Thus, since the
vibrationproof member 6 protrudes from the end surface
of the permanent magnet electric motor 1 in the
5 rotation axis C direction (specifically, the end
surface of the bracket 41 on the opposite output side),
it is possible to prevent the permanent magnet electric
motor 1 from being in direct contact with a target
object for attachment (e.g., casing of air conditioner)
10 and vibration from being transmitted thereto. Further,
since the thickness in the rotation axis C direction of
the vibrationproof member 6 (height of flange portion
62) interposed between the permanent magnet electric
motor 1 and the target object for attachment can be
15 ensured, the transmission of vibration from the
permanent magnet electric motor 1 to the target object
for attachment can be effectively suppressed.
[0041] The vibrationproof member placing portion 104
is disposed in a manner that does not overlap with the
20 protrusion 410 of the bracket 41 in the rotation axis C
direction. Further, each leg portion 107 includes the
leg-portion-side fastening portion 103 for fastening
the protrusion 410 of the bracket 41 at one end portion
of each leg portion 107 in the circumferential
25 direction. With this configuration, the vibrationproof
member 6 does not overlap with the protrusion 410 of
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the bracket 41 in the rotation axis C direction, so
that the height of the vibrationproof member 6
protruding from the end surface of the bracket 41 in
the rotation axis C direction can be canceled out by
5 the thickness Hb of the bracket 41 even if the
thickness of the vibrationproof member 6 in the
rotation axis C direction is increased. Specifically,
assuming that the protruding height of the
vibrationproof member 6 is Hp1, Hp1 = Hf – Hb. Thus, it
10 is possible to prevent the vibrationproof member 6 from
largely protruding from the end surface of the bracket
41 in the rotation axis C direction. In particular, if
the bearing house portion 43 formed in the bracket 41
does not protrude from the end surface of the bracket
15 41 as in this embodiment, the permanent magnet electric
motor 1 and the target object for attachment can be
disposed close to each other, and the increase in size
of the entire apparatus to which the permanent magnet
electric motor 1 is attached can be suppressed.
20 [0042] Fig. 8B is a schematic view of a permanent
magnet electric motor 91 and a vibrationproof member 96
of a comparative example. The permanent magnet electric
motor 91 of the comparative example and that of the
embodiment have a common structure except for a bracket
25 941 and the vibrationproof member 96. Here, in the
bracket 41 of the comparative example as shown in Fig.
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8B, a protrusion 9410 of the bracket 941 overlaps with
a vibrationproof member placing portion 9104, which is
formed in a leg portion 9107 of a motor shell 910, in
the rotation axis C direction. At that time, assuming
5 that the vibrationproof member 96 has a thickness Hf of
a flange portion 962 in the rotation axis C direction
(height of flange portion 962), which is the same
thickness as in the embodiment, a protruding height Hp2
of the vibrationproof member 6 is Hp2=Hf, and the
10 vibrationproof member 96 protrudes from the end surface
of the bracket 941 in the rotation axis C direction by
the height Hf of the flange portion 962 of the
vibrationproof member 96.
[0043] Therefore, as compared with the comparative
15 example shown in Fig. 8B, the permanent magnet electric
motor 1 of the embodiment shown in Figs. 1 to 8A can
prevent the vibrationproof member 6 from protruding in
the rotation axis C direction while ensuring the
thickness of the vibrationproof member 6 and
20 suppressing the transmission of vibration to the target
object for attachment.
[0044] As shown in Figs. 4, 6, and 7, any one of the
three leg portions 107 includes a slitted groove 105
for arranging the electrically conductive member 5 for
25 measures against electrolytic corrosion (see Fig. 5)
along the rotation axis C direction, the slitted groove
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105 being formed from the position on the most inner
diameter side of the cutout portion 104 in the radial
direction of the stator 2 (permanent magnet electric
motor 1) toward the rotation axis C. A slitted groove
5 108 for the electrically conductive member 5 is also
formed on the side surface and the end surface portion
13 (surface on the output side) of the motor shell 10
in the axis direction of the rotation axis C and the
radial direction (see Fig. 6).
10 The electrically conductive member 5 is a stripshaped
member for electrical conduction between the
first bearing storing portion 42 and the second bearing
storing portion 43. The electrically conductive member
5 is formed by, for example, punching a steel plate
15 into a strip shape and bending the obtained steel plate
into a squared U shape along the outer surfaces of the
motor shell 10 and the bracket 41 (see Fig. 5). The
electrically conductive member 5 allows the potentials
of the first bearing 33 and the second bearing 34 on
20 the outer race side to be the same, and thus the
occurrence of electrolytic corrosion can be suppressed.
[0045] Here, when the bracket 41 is fitted into the
motor shell 10, the slitted groove 416 of the bracket
41 and the slitted groove 108 formed in the outer
25 surface of the motor shell 10 become continuous, and
both the slitted grooves become a guide into which the
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strip-shaped electrically conductive member 5 is to be
embedded. This makes it possible to prevent the stripshaped
electrically conductive member 5 from protruding
from the surface of the resin shell of the permanent
5 magnet electric motor 1 and from dropping. As shown in
Fig. 5, the electrically conductive member 5 is
disposed to extend from the position of the flange
portion 422 of the first bearing storing portion 42 to
the position of the flange portion 432 of the second
10 bearing storing portion 43 through the slitted groove
416 of the bracket 41, the slitted groove 105 of the
leg portion 107, and the slitted groove 108 of the
motor shell 10. Further, before the vibrationproof
member 6 is fitted into the leg portion 107, the
15 electrically conductive member 5 is inserted into the
slitted groove 105 in advance, so that the
vibrationproof member 6 can press the electrically
conductive member 5 from the outside, and the
electrically conductive member 5 can be prevented from
20 dropping.
[0046] Both end portions of the electrically
conductive member 5 are disposed in clearance portions
AG1 and AG2 formed outside the tubular portions 421 and
431 of the bearing house portions 42 and 43,
25 respectively (see Figs. 2 and 5). With this
configuration, the electrically conductive member 5 for
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preventing electrolytic corrosion can be easily fixed
to the outer circumferential surfaces of the bearing
house portions 42 and 43 by using the clearance
portions AG1 and AG2.
5 [0047] As described above, the electric motor 1 of
this embodiment includes the rotor 3, the shaft 32
disposed along the rotation axis C of the rotor 3, the
main body 10 having a bottomed cylindrical shape having
an opening on one end side in the axis direction of the
10 rotation axis C, and the bracket that covers the
opening O of the main body 10. The rotor 3 is stored in
the internal space covered with the main body 10 and
the bracket 41. The main body 10 includes the plurality
of leg portions 107 extending outward in the radial
15 direction on one end side of the main body 10. The
bracket 41 includes the circular plate portion 414 and
the plurality of protrusions 410 protruding outward in
the radial direction from the circular plate portion
414. The leg portion 107 includes the leg-portion-side
20 fastening portion 103 to which the protrusion 410 of
the bracket 41 is to be fastened, and the
vibrationproof member placing portion 104 in which the
vibrationproof member 6 is to be disposed. Additionally,
the vibrationproof member placing portion 104 of the
25 leg portion 107 (the vibrationproof member 6 attached
to the leg portion 107) does not overlap with the
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protrusion 410 of the bracket 41 in the axis direction
of the rotation axis C.
This makes it possible to ensure vibrationproof
performance while suppressing the height of the
5 vibrationproof member 6 protruding from the shell of
the electric motor 1 in the axis direction of the
center axis 32.
Reference Signs List
[0048]
10 1 electric motor
10 motor shell (main body)
103 leg-portion-side fastening portion
104 vibrationproof member placing portion (cutout
portion)
15 107 leg portion
2 stator
21 stator core
3 rotor
31 permanent magnet portion
20 32 shaft
33 first bearing
34 second bearing
41 bracket
414 circular plate portion
25 410 protrusion
42 first bearing storing portion
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43 second bearing storing portion
6 vibrationproof member
61 central core portion
62 flange portion
5 63 insertion hole
O opening

Claims
[1] An electric motor, comprising:
a rotor;
a shaft disposed along a rotation axis of the
5 rotor;
a main body having a bottomed cylindrical shape
having an opening on one end side in an axis direction
of the rotation axis; and
a bracket that covers the opening of the main body,
10 the rotor being stored in an internal space
covered with the main body and the bracket, wherein
the main body includes a plurality of leg portions
extending outward in a radial direction on the one end
side of the main body,
15 the bracket includes a circular plate portion and
a plurality of protrusions protruding outward in the
radial direction from the circular plate portion,
each of the leg portions includes a leg-portionside
fastening portion to which the protrusion of the
20 bracket is to be fastened, and a vibrationproof member
placing portion in which a vibrationproof member is to
be disposed, and
the vibrationproof member placing portion of the
leg portion is disposed in a manner that does not
25 overlap with the protrusion of the bracket in the axis
direction.
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[2] The electric motor according to claim 1, wherein
the protrusion of the bracket is disposed in a
manner that overlaps with the leg portion in the axis
direction.
5 [3] The electric motor according to claim 1 or 2,
wherein
the vibrationproof member is formed into a bobbin
shape including a flange portion, and
the flange portion has a larger height in the axis
10 direction than a thickness of the bracket.
[4] The electric motor according to any one of claims
1 to 3, wherein
the protrusion of the bracket is disposed in a
manner that does not overlap with the vibrationproof
15 member.
[5] The electric motor according to any one of claims
1 to 4, wherein
the leg portion is formed such that a length in a
circumferential direction becomes shorter outward in
20 the radial direction.
[6] The electric motor according to any one of claims
1 to 5, wherein
the vibrationproof member placing portion of the
leg portion is a cutout portion obtained by cutting out
25 an outer diameter side of the leg portion.
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Abstract
[Abstract]
ELECTRIC MOTOR
[Object] To provide an electric motor capable of
5 ensuring vibrationproof performance while suppressing
the height of a vibrationproof member protruding from
the shell of the electric motor in an axis direction of
a rotation axis.
[Solving Means] An electric motor according to an
10 aspect of the present invention includes: a rotor; a
shaft disposed along a rotation axis of the rotor; a
main body having a bottomed cylindrical shape having an
opening on one end side in an axis direction of the
rotation axis; and a bracket that covers the opening of
15 the main body, the rotor being stored in an internal
space covered with the main body and the bracket. The
main body includes leg portions extending outward in a
radial direction on the one end side of the main body.
The bracket includes a circular plate portion and
20 protrusions protruding outward in the radial direction
from the circular plate portion. The leg portion
includes a leg-portion-side fastening portion to which
the protrusion of the bracket is to be fastened, and a
vibrationproof member placing portion in which a
25 vibrationproof member is to be disposed. The
vibrationproof member placing portion is disposed in a
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manner that does not overlap with the protrusion of the
bracket in the axis direction of the rotation axis.
[Selected Drawing] Fig. 1