FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10, Rule 13]
ELECTRIC MOTOR;
MITSUBISHI ELECTRIC CORPORATION, A CORPORATION ORGANISED AND
EXISTING UNDER THE LAWS OF JAPAN, WHOSE ADDRESS IS 7-3,
MARUNOUCHI 2-CHOME, CHIYODA-KU, TOKYO 100-8310, JAPAN
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE
INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.
2
DESCRIPTION
5 Technical Field
[0001] The present disclosure relates to an electric motor.
Background Art
[0002] An electric motor includes a shaft, a rotor that is attached to the shaft to
integrally rotate together, and a stator that opposes the rotor in a radially spaced apart
10 manner. Energizing the electric motor leads to a rise of temperatures of a stator core
and a stator coil of the stator and a rotor core and a rotor conductor of the rotor. To
address this, an interior of the electric motor is cooled with an air flow through an airhole
formed in the stator core, a gap between the stator core and the rotor core, and the like.
An example of this type of electric motor is disclosed in Patent Literature 1. In the
15 electric motor disclosed in Patent Literature 1, an airhole is formed in the stator core to
cool the electric motor. This electric motor includes a pair of rings fitting over the stator
core along a rotation axis direction of the shaft and having airholes. An air flows
through each of the airholes of the pair of rings and the stator core cools the interior of the
electric motor.
20 Citation List
Patent Literature
[0003] Patent Literature 1: Unexamined Japanese Patent Application Publication
No. 2012-016210
Summary of Invention
25 Technical Problem
[0004] The rings of the electric motor disclosed in Patent Literature 1 have a double
structure of a radial outer tube and a radial inner tube. In this ring, air flows in a gap
3
between the radial outer tube and the radial inner tube. The ring imposes constraints on
reduction in size of the electric motor by radial thicknesses of the radial outer tube and the
radial inner tube of the ring.
[0005] In view of the above circumstances, an objective of the present disclosure is
to reduce size of the electric motor while maintaining cooling effects 5 for the electric
motor.
Solution to Problem
[0006] To achieve the above objective, an electric motor according to the present
disclosure includes a shaft, a rotor, a stator, a frame, a first partition member, and a
10 second partition member. The shaft is supported rotatably around a rotational axis.
The rotor is disposed radially outward of the shaft and rotates integrally with the shaft.
The stator opposes the rotor in a radially spaced apart manner. The frame contains the
rotor and the stator and has a tubular shape with both ends closed, and the frame has an
inflow hole that allows an outside air to flow in and an outflow hole that allows the
15 outside air having flowed in to flow out. The first partition member is located nearer to
the inflow hole than the stator and forms, between the first partition member and an inner
circumferential surface of the frame, a first ventilation path for a flow of the outside air
having flowed in from the inflow hole. The second partition member is located nearer
to the outflow hole than the stator and forms, between the second partition member and
20 the inner circumferential surface of the frame, a second ventilation path for a flow of the
outside air. The stator has a third ventilation path penetrating through the stator from
one end to another end of the stator in a direction of the rotational axis and
communicating with the first ventilation path and the second ventilation path. The first
partition member includes a first tubular member having an outer circumferential surface
25 opposing the inner circumferential surface of the frame in a spaced apart manner, and a
first attachment member extending in a direction from the outer circumferential surface
of the first tubular member to the inner circumferential surface of the frame and fixed to
4
the first tubular member and the frame.
Advantageous Effects of Invention
[0007] The present disclosure can achieve reduction in size of the electric motor in
a radial direction by forming a ventilation path by the first partition member, the second
partition member, 5 and the frame.
Brief Description of Drawings
[0008] FIG. 1 is a cross-sectional view illustrating an electric motor according to
Embodiment 1 of the present disclosure;
FIG. 2 is a perspective view of a first partition member according to Embodiment
10 1;
FIG. 3 is a cross-sectional view of an electric motor according to Embodiment 2 of
the present disclosure;
FIG. 4 is a perspective view of a second partition member according to
Embodiment 2;
15 FIG. 5 is a cross-sectional view of an electric motor according to Embodiment 3 of
the present disclosure;
FIG. 6 is a perspective view of a first modified example of the first partition
member according to an embodiment of the present disclosure;
FIG. 7 is a perspective view of a second modified example of the first partition
20 member according to an embodiment of the present disclosure;
FIG. 8 is a perspective view of a third modified example of the first partition
member according to an embodiment of the present disclosure; and
FIG. 9 is a diagram illustrating a fan and the first partition member according to an
embodiment of the present disclosure.
25 Description of Embodiments
[0009] An electric motor according to embodiments of the present disclosure is
described below in detail with reference to the drawings. The same reference numerals
5
are used throughout the drawings to refer to the same or like parts.
[0010] Embodiment 1
An electric motor according to Embodiment 1 is described using as an example an
electric motor to be used for drive of a railway vehicle. As illustrated in FIG. 1, an
electric motor 1 according to Embodiment 1 includes a frame 11, a shaft 5 15, a rotor 16
that rotates integrally with the shaft 15, and a stator 17 attached to the frame 11. In FIG.
1, a Z axis is in a vertical direction, a Y axis is in parallel to a rotational axis AX of the
shaft 15, and an X axis is orthogonal to the Y axis and the Z axis. In FIG. 1, the
rotational axis AX is indicated by a dot-and-dash line. Since the electric motor 1 is used
10 as an electric motor for drive of a railway vehicle, the frame 11 is fixed to a bogie of the
railway vehicle, and one end of the shaft 15 is coupled to an axle of the railway vehicle
via a coupling and gears. The frame 11 includes a stator framework 12 having a tubular
shape and brackets 13 and 14 that block both of Y-axis-direction ends of the stator
framework 12. The stator framework 12 and the bracket 14 may be an integral tubular
15 stator framework with one end closed, instead of being separate parts.
[0011] The rotor 16 is disposed radially outward of the shaft 15. The rotor 16
includes a rotor core 18 fitting over the shaft 15 and a rotor conductor 19 inserted into a
groove on an outer circumferential surface of the rotor core 18. The stator 17 includes a
stator core 20 attached to the stator framework 12 of the frame 11 and a stator conductor
20 21 inserted into a groove on the stator core 20. The outer circumferential surface of the
rotor core 18 opposes the inner circumferential surface of the stator core 20 in a spaced
apart manner. The electric motor 1 further includes bearings 22 and 23 that rotatably
support the shaft 15. The bearing 22 is held by the bracket 13 and the bearing 23 is held
by the bracket 14. One end of the shaft 15 that is closer to the bracket 13 is coupled to
25 the axel of the railway vehicle via a coupling and gears that are unillustrated. Rotation
of the shaft 15 provides power to the railway vehicle. The one end of the shaft 15
coupled to the axle is referred to as a drive side and the other side thereof is referred to as
6
a non-drive side.
[0012] To cool the interior of the electric motor 1, the frame 11 has an inflow hole
24 that allows an outside air, which is an air in an exterior of the electric motor 1, to flow
in the interior of the electric motor 1 and an outflow hole 25 that allows the outside air
having flowed in to flow out to the exterior of the electric motor 1, and 5 the electric motor
1 includes a fan 26 attached to the drive side of the shaft 15 and configured to rotate
integrally with the shaft 15. To form a flow path of the outside air in the interior of the
electric motor 1, the electric motor 1 further includes a first partition member 27 that
forms a first ventilation path 28 between the first partition member 27 and the stator
10 framework 12, and a second partition member 29 that forms a second ventilation path 30
between the second partition member 29 and the stator framework 12. Furthermore, a
third ventilation path 31 is formed in the stator core 20. The third ventilation path 31
extends through the stator core 20 from one end to another end of the stator core 20 in the
rotational axis AX, and communicates with the first ventilation path 28 and the second
15 ventilation path 30. The stator core 20 has a plurality of third ventilation paths 31
spaced apart circumferentially.
[0013] A structure for cooling the interior of the electric motor 1 is described in
detail. The frame 11 has the inflow hole 24 on an end side opposing the fan 26 in the
direction of the rotational axis AX, that is, in the bracket 13. The frame 11 also has an
20 outflow hole 25 in the bracket 14. Integral rotation of the fan 26 attached to the drive
side of the shaft 15 together with the shaft 15 allows the outside air to flow from the
inflow hole 24 in the interior of the electric motor 1. Since the rotation of the fan 26 can
produce a radial outward flow of air, the outside air having flowed from the inflow hole
24 in the interior of the electric motor 1 flows in the first ventilation path 28 formed by
25 the first partition member 27. An end portion near the inflow hole 24 of the first
partition member 27 is located close to a radial end portion of the fan 26. For example,
a spacing between the end portion near the inflow hole 24 of the first partition member 27
7
and the radial end portion of the fan 26 is less than 10 millimeters. This can suppress
contact of foreign substances contained in the outside air having flowed in from the
inflow hole 24 through between the fan 26 and the first partition member 27 with the
stator conductor 21, the rotor conductor 19, and the like, and failure of the electric motor
1 due to the contact of the foreign substances with the stator conductor 5 21, the rotor
conductor 19, and the like is can be prevented.
[0014] FIG. 2 illustrates a structure of the first partition member 27 forming the first
ventilation path 28. The first partition member 27 includes a first tubular member 271
having a cylindrical shape and four first attachment members 272 having a plate-like
10 shape. As illustrated in FIG. 1, the first tubular member 271 is disposed in contact with
an end surface of the stator core 20 in the rotational axis AX. The outer circumferential
surface of the first tubular member 271 is located more radially inward than the third
ventilation paths 31 of the stator core 20. The first attachment member 272 extends in a
direction from the outer circumferential surface of the first tubular member 271 to the
15 inner circumferential surface of the stator framework 12. The first attachment member
272 is fixed to the first tubular member 271 and the stator framework 12. This fastens
the first tubular member 271 to the stator framework 12 via the first attachment member
272. The four first attachment members 272 includes a pair of first attachment members
272 having main surfaces parallel to a YZ plane and disposed symmetrically relative to
20 the rotational axis AX, and a pair of first attachment member 272 having main surfaces
parallel to an XY plane and disposed symmetrically relative to the rotational axis AX.
[0015] Space between the outer circumferential surface of the first tubular member
271 fixed via the first attachment member 272 to the stator framework 12 and the inner
circumferential surface of the stator framework 12 is the first ventilation path 28. The
25 first ventilation path 28 communicates with the third ventilation paths 31 formed in the
stator core 20. The structure of the second partition member 29 that communicates with
the third ventilation paths 31 and forms the second ventilation path 30 leading to the
8
outflow hole 25 is similar to the first partition member 27 illustrated in FIG. 2. The
second partition member 29 includes a second tubular member 291 having a cylindrical
shape and four second attachment members 292 having a plate-like shape. As
illustrated in FIG. 1, the second tubular member 291 is disposed in contact with an end
surface of the stator core 20 in the rotational axis AX. The second 5 attachment member
292 extends in a direction from the outer circumferential surface of the second tubular
member 291 to the inner circumferential surface of the stator framework 12. The
second attachment member 292 is fixed to the second tubular member 291 and the stator
framework 12. This fastens the second tubular member 291 to the stator framework 12
10 via the second attachment member 292. Similarly to the first attachment member 272
illustrated in FIG. 2, the four second attachment members 292 includes a pair of second
attachment members 292 having main surfaces parallel to the YZ plane and disposed
symmetrically relative to the rotational axis AX, and a pair of second attachment member
292 having main surfaces parallel to the XY plane and disposed symmetrically relative to
15 the rotational axis AX. Space between the outer circumferential surface of the second
tubular member 291 fixed to the stator framework 12 and the inner circumferential
surface of the stator framework 12 is the second ventilation path 30.
[0016] Upon energization of the electric motor 1 having the aforementioned
structure, temperatures of the stator core 20 and the stator conductor 21 increase. Upon
20 energization of the electric motor 1 and integral rotation of the rotor core 18 and the shaft
15, the fan 26 rotates together with the shaft 15 and then air outside the electric motor 1
flows through the inflow hole 24 in the interior of the electric motor 1. The outside air
having flowed through the inflow hole 24 in the interior of the electric motor 1 flows
through the first ventilation path 28, the third ventilation path 31, and the second
25 ventilation path 30 in this order, and flows out through the outflow hole 25 to the outside
of the electric motor 1. The outside air having flowed in the interior of the electric
motor 1 flowing through the third ventilation path 31 can cool the stator core 20 and the
9
stator conductor 21, which suppress increase in temperatures of the stator core 20 and the
stator conductor 21. Although the outside air having flowed in the interior of the
electric motor 1 contains foreign substances such as dust or moisture, this outside air
flows through the first ventilation path 28, the third ventilation path 31, and the second
ventilation path 30 in this order and flows out through the outflow hole 5 25 to the outside
of the electric motor 1, as described above. Thus, compared with a ventilated electric
motor that allows outside air to flow a gap between the stator and the rotor, the electric
motor 1 can suppress failure of the electric motor 1 caused due to attachment of the
foreign substances to the stator conductor 21, the rotor conductor 19, and the like.
10 [0017] As described above, in the electric motor 1 according to Embodiment 1, the
first ventilation path 28 is formed between the first partition member 27 and the stator
framework 12 and the second ventilation path 30 is formed between the second partition
member 29 and the stator framework 12. The first partition member 27 includes the
first tubular member 271, and the first attachment member 272 extending from the outer
15 circumferential surface of the first tubular member 271. The second partition member
29 includes the second tubular member 291, and the second attachment member 292
having a plate-like shape extending from the outer circumferential surface of the second
tubular member 291. The first partition member 27 and the second partition member 29
can have a reduced radial thickness, compared with a ring member having a double
20 structure of a radial outer tube and a radial inner tube. Thus reduction in size of the
electric motor 1 in the radial direction can be achieved while maintaining cooling effects
for the electric motor 1.
[0018] Embodiment 2
The structure of forming a flow path through which the outside air flows is not
25 limited to the first partition member 27 and the second partition member 29. Any
structure that can guide the outside air to the third ventilation path 31 without contacting
the foreign substances contained in the outside air with the stator conductor 21, the rotor
10
conductor 19, and the like and without increasing a size in the radial direction can be used
as a structure of forming a flow path for a flow of the outside air. As an example, an
electric motor 2 according to Embodiment 2 illustrated in FIG. 3 includes a second
partition member 32 in place of the second partition member 29 included in the electric
motor 1. Unlike the frame 11 in Embodiment 1, the frame 11 of this 5 embodiment has
the outflow hole 25 in the stator framework 12.
[0019] The second partition member 32 has a shape of a tube as illustrated in FIG. 4,
and a diameter of the tube increases from one end to the other end of the tube. As
illustrated in FIG. 3, one end of the tube is fixed to an end side of the stator core 20 in a
10 direction of the rotational axis AX, and another end of the tube is fixed to the inner
circumferential surface of the stator framework 12 at a position farther away from the
stator core 20 than the outflow hole 25. With this structure, the second partition
member 32 forms the second ventilation path 33 between the second partition member 32
and the inner circumferential surface of the stator framework 12. The second ventilation
15 path 33 communicates with the third ventilation path 31 to form a flow path of the
outside air to the outflow hole 25.
[0020] Upon energization of the electric motor 2 having the aforementioned
structure, similarly to Embodiment 1, the fan 26 rotates together with the shaft 15 and
then air outside the electric motor 2 flows through the inflow hole 24 in the interior of the
20 electric motor 2. The outside air having flowed through the inflow hole 24 in the
interior of the electric motor 2 flows through the first ventilation path 28, the third
ventilation path 31, and the second ventilation path 33 in this order, and flows out
through the outflow hole 25 to the outside of the electric motor 2. The outside air
flowing through the third ventilation path 31 can cool the stator core 20 and the stator
25 conductor 21, which suppress increase in temperatures of the stator core 20 and the stator
conductor 21. Although the outside air contains foreign substances such as dust or
moisture, this outside air flows through the first ventilation path 28, the third ventilation
11
path 31, and the second ventilation path 33 in this order and flows out through the
outflow hole 25, as described above. Thus, compared with a ventilated electric motor
that allows outside air to be taken in, failure of the electric motor 1 caused due to
attachment of the foreign substances to the stator conductor 21, the rotor conductor 19,
and the like 5 can be suppressed.
[0021] As described above, in the electric motor 2 according to Embodiment 2, the
second ventilation path 33 is formed between the second partition member 32 and the
stator framework 12. With this arrangement of the outflow hole 25 in the stator
framework 12, a Y-axis-direction length of the second partition member 32 is shorter
10 than the second partition member 29 included in the electric motor 1 according to
Embodiment 1. That is, reduction in size of the electric motor 2 can be achieved with
the Y-axis-direction length of the electric motor 2 being shorter than the Y-axis-direction
length of the electric motor 1.
[0022] Embodiment 3
15 The structure of taking the outside air in the interior of the electric motor is not
limited to the inflow hole 24, the outflow hole 25, and the fan 26. Any air blowing
mechanism, an intake air mechanism, and the like can be adopted as long as the objective
of the present disclosure can be achieved. As an example, an electric motor 3 according
to Embodiment 3 illustrated in FIG. 5 includes, in place of the fan 26 included in the
20 electric motor 1 according to Embodiment 1, an exterior fan 34 that is attached to the
shaft 15 on the non-drive side and rotates integrally with the shaft 15. The electric
motor 3 further includes a cover 35 that covers the exterior fan 34, and the cover 35 has
an outside inflow hole 36 through which the outside air flows.
[0023] Any structure that can guide the outside air to the third ventilation path 31
25 without contacting the foreign substances contained in the outside air with the stator
conductor 21, the rotor conductor 19, and the like and without increasing a size in the
radial direction can be used as a structure of forming a flow path for a flow of the outside
12
air. As an example, the electric motor 3 includes a first partition member 37 and a
second partition member 39, in place of the first partition member 27 and the second
partition member 29 included in the electric motor 1 according to Embodiment 1. The
frame 11 has the inflow hole 24 in the bracket 14 and the outflow hole 25 in the stator
framework 12. That is, the outside air having flowed in the interior of 5 the electric motor
3 flows from the non-drive side to the drive side, unlike Embodiments 1 and 2.
[0024] Similarly to the first partition member 27 illustrated in FIG. 2, the first
partition member 37 includes a first tubular member 371 having a cylindrical shape and
four first attachment members 372 having a plate-like shape. As illustrated in FIG. 5,
10 the first tubular member 371 is disposed in contact with the end surface of the stator core
20 in the rotational axis AX and in contact with the end surface of the bracket 14 in the
rotational axis AX. The first tubular member 371 is fixed to the end surface of the
bracket 14 in the rotational axis AX at a position more radially inward than the inflow
hole 24. The first attachment member 372 extends in a direction from the outer
15 circumferential surface of the first tubular member 371 to the inner circumferential
surface of the stator framework 12. The first attachment member 372 is fixed to the first
tubular member 371 and the stator framework 12. This fastens the first tubular member
371 to the stator framework 12 via the first attachment member 372. The four first
attachment members 372 includes a pair of first attachment members 372 having main
20 surfaces parallel to the YZ plane and disposed symmetrically relative to the rotational
axis AX, and a pair of first attachment member 372 having main surfaces parallel to the
XY plane and disposed symmetrically relative to the rotational axis AX. Space between
the outer circumferential surface of the first tubular member 371 fixed via the first
attachment member 372 to the stator framework 12 and the inner circumferential surface
25 of the stator framework 12 is the first ventilation path 38. The first ventilation path 38
communicates with the third ventilation path 31 formed in the stator core 20.
[0025] Similarly to the second partition member 32 illustrated in FIG. 4, the second
13
partition member 39 has a shape of a tube, and a diameter of the tube increases from one
end to the other end of the tube. As illustrated in FIG. 5, one end of the tube is fixed to
an end side of the stator core 20 in a direction of the rotational axis AX, and another end
of the tube is fixed to the inner circumferential surface of the stator framework 12 at a
position farther away from the stator core 20 than the outflow hole 5 25. With this
structure, the second partition member 39 forms the second ventilation path 40 between
the second partition member 39 and the inner circumferential surface of the stator
framework 12. The second ventilation path 40 communicates with the third ventilation
path 31 to form a flow path of the outside air to the outflow hole 25.
10 [0026] Upon energization of the electric motor 3 having the aforementioned
structure, the exterior fan 34 rotates together with the shaft 15, and air flows from the
outside inflow hole 36 formed in the cover 35 in the interior of the cover 35. Air having
flowed from the outside inflow hole 36 flows from the inflow hole 24 to the interior of
the electric motor 3. The outside air having flowed through the inflow hole 24 in the
15 interior of the electric motor 3 flows through the first ventilation path 38, the third
ventilation path 31, and the second ventilation path 40 in this order, and flows out
through the outflow hole 25 to the outside of the electric motor 3. The outside air
flowing through the third ventilation path 31 can cool the stator core 20 and the stator
conductor 21, which suppresses increase in temperatures of the stator core 20 and the
20 stator conductor 21. Although the outside air contains foreign substances such as dust
or moisture, this outside air flows through the first ventilation path 38, the third
ventilation path 31, and the second ventilation path 40 in this order and flows out through
the outflow hole 25, as described above. Thus, compared with a ventilated electric
motor that allows outside air to be taken in, failure of the electric motor 3 caused due to
25 attachment of the foreign substances to the stator conductor 21, the rotor conductor 19,
and the like can be suppressed. Since the first partition member 37 is disposed in
contact with the bracket 14 and the stator core 20, and the second partition member 39 is
14
disposed in contact with the stator core 20 and the stator framework 12, leakage of the
outside air to the interior of the electric motor 3 from the flow path formed by the first
ventilation path 38, the third ventilation path 31, and the second ventilation path 40 can
be suppressed compared with the electric motors 1 and 2. Thus, compared with the
electric motors 1 and 2, failure of the electric motor 3 caused due to 5 attachment of the
foreign substances to the stator conductor 21, the rotor conductor 19, and the like can be
suppressed.
[0027] As described above, in the electric motor 3 according to Embodiment 3, the
first ventilation path 38 is formed between the first partition member 37 and the stator
10 framework 12 and the second ventilation path 40 is formed between the second partition
member 39 and the stator framework 12. The first partition member 37 includes the
first tubular member 371, and the first attachment member 372 having a plate-like shape
and extending from the outer circumferential surface of the first tubular member 371.
The first partition member 37 can have a reduced radial thickness, compared with a ring
15 member having a double structure of a radial outer tube and a radial inner tube. Thus
reduction in size of the electric motor 3 in the radial direction can be achieved while
maintaining cooling effects for the electric motor 3. With this arrangement of the
outflow hole 25 in the stator framework 12, a Y-axis-direction length of the second
partition member 39 is shorter than the second partition member 29 included in the
20 electric motor 1 according to Embodiment 1. That is, reduction in size of the electric
motor 3 can be achieved with the Y-axis-direction length of the electric motor 3 being
shorter than the Y-axis-direction length of the electric motor 1. Since the electric motor
3 is not provided with a fan therein, the electric motor 3 do not need to have space for
rotating a fan, which can achieve reduction in size compared with the electric motors 1
25 and 2.
[0028] The present disclosure is not limited to the aforementioned embodiments.
The first partition member is not limited to the aforementioned example, and has any
15
shape forming a ventilation path between the first partition member and the frame 11 and
includes a tubular member and a plate-like member extending from the tubular member.
Some of modified examples of the shape of the first partition member are illustrated in
FIGS. 6 to 8. The first partition member 41 illustrated in FIG. 6 includes a first tubular
member 411 and four first attachment members 412 having a plate-5 like shape. Unlike
the first tubular members 271 and 371 having a constant diameter, a shape of the first
tubular member 411 can be changed in accordance with an internal structure of the
electric motors 1 to 3. Changing the shape of the first tubular member 411 in
accordance with the internal structure of the electric motors 1 to 3 can reduce the size of
10 the electric motors 1 to 3 in the radial direction more than when a flow path is formed
with a member having a constant diameter adapted to a portion having the greatest radial
size.
[0029] The first tubular member of the first partition member may have a slit, a
cutout, a through hole, and/or the like. In this case, a flow path is formed around the slit,
15 the cutout, the through hole, and/or the like, and a member for separating the flow path
and the interior of the electric motor is disposed. An example of the first tubular
member with the slit, the cutout, the through hole, or the like is illustrated in FIG. 7.
The first partition member 42 illustrated in FIG. 7 has a first tubular member 421 and
three first attachment members 422. The first tubular member 421 has a slit 423
20 extending in the direction of the rotational axis AX. Two barriers 424 are disposed
around the slit 423. The first attachment member 422 and the barriers 424 extend from
the outer circumferential surface of the first tubular member 421 toward the inner
circumferential surface of the stator framework 12 and are fixed to the first tubular
member 421 and the stator framework 12. The flow path and the interior of the electric
25 motor are separated by the barriers 424.
[0030] Another example of the first tubular member with the slit, the cutout, the
through hole, or the like is illustrated in FIG. 8. The first partition member 43 illustrated
16
in FIG. 8 has a first tubular member 431 and two first attachment members 432. The
first tubular member 431 has through holes 433 and 434. A barrier 435 is disposed
around the though hole 433, and a tubular barrier 436 is disposed around the through hole
434. The barriers 435 and 436 extend from the outer circumferential surface of the first
tubular member 431 to the inner circumferential surface of the stator 5 framework 12, and
are fixed to the first tubular member 431 and the stator framework 12. The flow path
and the interior of the electric motor are separated by the barriers 435 and 436.
[0031] The structure of the second partition member 29 in FIG. 1 may be similar to
that of the modified example of the first partition member illustrated in FIGS. 6 to 8.
10 The lengths of the first attachment members 272, 372, 412, 422, and 432 in the direction
of the rotation axis AX may be shorter than those of the first tubular members 271, 371,
411, 421, and 431 in the direction of the rotational axis AX. The length of the second
attachment member 292 in the direction of the rotational axis AX may be shorter than
that of the second tubular members 291 in the direction of the rotational axis AX.
15 [0032] Any combination of embodiments of the aforementioned embodiments can
be used. For example, the electric motor 3 includes a pair of first partition members that
sandwich the stator core 20 and has the outflow hole 25 in the bracket 13. The fan 26
may be attached to the non-drive side of the shaft 15 in accordance with where the
electric motor is disposed. In this case, the inflow hole 24 is formed in the bracket 14
20 and the outflow hole 25 is formed in the bracket 13 or the stator framework 12.
[0033] In the aforementioned embodiments, an end portion of the first partition
member 27 that is located near the inflow hole 24 being located close to a radial end
portion of the fan 26 can suppress a flow of the outside air through between the fan 26
and the first partition member 27. To ensure suppression of the outside air passing
25 through between the fan 26 and the first partition member 27, a flow path between the fan
26 and the first partition member 27 may have a shape of a labyrinth flow path.
[0034] An example of a case in which a flow path between the fan 26 and the first
17
partition member 27 is a labyrinth flow path is illustrates in FIG. 9. A case in which the
radial end portion of the fan 26 opposes an end portion near the inflow hole 24 of the first
partition member 27 opposes in the direction of the rotational axis AX is described as an
example. The fan 26 has a depression and projection portion 261 on a surface of the
radial end portion that is located near the stator 17. The end portion that 5 is a portion of
the first tubular member 271 of the first partition member 27 and is located near the
inflow hole 24 has a depression and projection portion 273. Opposing of the depression
and projection portion 261 and the depression and projection portion 273 in the direction
of the rotational axis Ax forms a labyrinth flow path between the fan 26 and the first
10 partition member 27. For example, the depression and projection portion 261 and the
depression and projection portion 273 are opposed to each other with a spacing
therebetween of less than 10 millimeters in the direction of the rotational axis AX. With
the above configuration, the flow path between the fan 26 and the first partition member
27 is a labyrinth flow path, which can suppress contact of foreign substances contained in
15 the outside air through between the fan 26 and the first partition member 27 with the
stator conductor 21, the rotor conductor 19, and the like. An abnormality of the electric
motor caused due to contact of the foreign substances with the stator conductor 21, the
rotor conductor 19, and the like is suppressed.
[0035] In the aforementioned embodiments, the first partition member 37 is
20 disposed in contact with the bracket 14, but a labyrinth flow path may be formed between
the first partition member 37 and the bracket 14.
[0036] The shape and orientation of the first attachment member 272 and a position
of attachment to the first tubular member 271 are not limited to the aforementioned
examples. The first attachment member 272 may have any shape that enables the first
25 tubular member 271 to be fixed to the stator framework 12 without preventing a flow of
the outside air in the first ventilation path 28 and without increasing a radial size. As an
example, the shape of the first attachment member 272 may have a rod-like shape, or
18
may be a shape extending in a direction crossing the rotational axis AX and fixed to the
first tubular member 271 and the stator framework 12. The interior of the electric
motors 1 to 3 may be cooled by take-in of cooling air blown by an exterior blower that
operates independently of rotation of the shaft 15. The same applies to the first
attachment members 372, 412, 422, and 432 and the second attachment 5 member 292.
[0037] The foregoing describes some example embodiments for explanatory
purposes. Although the foregoing discussion has presented specific embodiments,
persons skilled in the art will recognize that changes may be made in form and detail
without departing from the broader spirit and scope of the invention. Accordingly, the
10 specification and drawings are to be regarded in an illustrative rather than a restrictive
sense. This detailed description, therefore, is not to be taken in a limiting sense, and the
scope of the invention is defined only by the included claims, along with the full range of
equivalents to which such claims are entitled.
Reference Signs List
15 [0038] 1, 2, 3 Electric motor
11 Frame
12 Stator framework
13, 14 Bracket
15 Shaft
20 16 Rotor
17 Stator
18 Rotor core
19 Rotor conductor
20 Stator core
25 21 Stator conductor
22, 23 Bearing
24 Inflow hole
19
25 Outflow hole
26 Fan
27, 37, 41, 42, 43 First partition member
28, 38 First ventilation path
29, 32, 39 Second 5 partition member
30, 33, 40 Second ventilation path
31 Third ventilation path
34 Exterior fan
35 Cover
10 36 Outside inflow hole
261, 273 Depression and projection portion
271, 371, 411, 421, 431 First tubular member
272, 372, 412, 422, 432 First attachment member
291 Second tubular member
15 292 Second attachment member
423 Slit
424, 435, 436 Partition wall
433, 434 Through hole
AX Rotational axis
20
We Claim :
1. An electric motor comprising:
a shaft supported rotatably around a rotational axis;
a rotor disposed radially outward of the shaft and configured to rotate integrally
5 with the shaft;
a stator opposing the rotor in a radially spaced apart manner;
a frame containing the rotor and the stator and having a tubular shape with both
ends closed, the frame having an inflow hole that allows an outside air to flow in and an
outflow hole that allows the outside air having flowed in to flow out;
10 a first partition member located nearer to the inflow hole than the stator and
configured to form, between the first partition member and an inner circumferential
surface of the frame, a first ventilation path for a flow of the outside air having flowed in
from the inflow hole; and
a second partition member located nearer to the outflow hole than the stator and
15 configured to form, between the second partition member and the inner circumferential
surface of the frame, a second ventilation path for a flow of the outside air, wherein
the stator has a third ventilation path penetrating through the stator from one end to
another end of the stator in a direction of the rotational axis and configured to
communicate with the first ventilation path and the second ventilation path, and
20 the first partition member includes
a first tubular member having an outer circumferential surface opposing the
inner circumferential surface of the frame in a spaced apart manner, and
a first attachment member extending in a direction from the outer
circumferential surface of the first tubular member to the inner circumferential surface of
25 the frame and fixed to the first tubular member and the frame.
2. The electric motor according to claim 1, wherein the first partition member
21
includes the first tubular member having a cylindrical shape, and a plurality of the first
attachment members extending in the direction from the outer circumferential surface of
the first tubular member to the inner circumferential surface of the frame and the
direction of the rotational axis.
5
3. The electric motor according to claim 1 or 2, further comprising:
a fan disposed inside the frame and configured to rotate integrally with the shaft,
wherein
the frame has the inflow hole on an end side opposing the fan in the direction of
10 the rotational axis, and
an end portion that is one of both end portions of the first partition member in the
direction of the rotational axis and located near the inflow hole is in proximity to an end
portion of the fan in a radial direction of the shaft.
15 4. The electric motor according to claim 1 or 2, further comprising:
an exterior fan disposed outside the frame and configured to rotate integrally with
the shaft; and
a cover that covers the exterior fan, wherein
the cover has an outside inflow hole that allows the outside air to flow into an
20 interior of the cover,
the frame has the inflow hole on an end side that is one of both end sides of the
frame in the direction of the rotational axis and located near the exterior fan, and
the first partition member forms, between the first partition member and the inner
circumferential surface of the frame, the first ventilation path leading from the inflow
25 hole to the third ventilation path.
5. The electric motor according to any one of claims 1 to 4, wherein
22
the second partition member includes
a second tubular member having an outer circumferential surface opposing
the inner circumferential surface of the frame in a spaced apart manner; and
a second attachment member having a plate-like shape, extending in a
direction from the outer circumferential surface of the second tubular member 5 to the inner
circumferential surface of the frame, and fixed to the second tubular member and the
frame to attach the second tubular member to the frame.
6. The electric motor according to any one of claims 1 to 4, wherein
10 the frame has the outflow hole at a tubular portion of the frame, and
the second partition member has a shape of a tube, one end of the tube is fixed to
an end side of the stator in the direction of the rotational axis, and another end of the tube
is fixed to the inner circumferential surface of the frame at a position farther away from
the stator than the outflow hole to form the second ventilation path between the second
15 partition member and the inner circumferential surface of the frame.