faTRANSPERFECT
`
`1, Michael O’Keeffe, certify that I am fluent (conversant) in the Japanese and English languages, and that
`the attached English document is an accurate translation of the Japanese document attached entitled Tan
`IP2006-14564A. I understand that willful false statements and the like are punishable by fine or
`imprisonment, or both, under Section 100} of Title 18 of the United States Code.
`
`
`
`Michael O’Keeffe
`
`10 January 20 1 8
`
`LANGUAGE AND TECHNOLOGY SOLUTEGNS FOR GLOBAL BUSINESS
`THREE PARK AVENUE, 39TH FLOOR, NEW YORK, NY 10015 | T 212.689.5555 i
`F 212.689.1059 I WWW.TRANSPERFECT.CDM
`OFFICES IN 92 CITIES WORLDWIDE
`
`Am. Honda V. IV 11 - IPR2018-00349
`
`PET_HONDA_l 0 l 3 -0001
`
`Am. Honda v. IV II - IPR2018-00349
`PET_HONDA_1013-0001
`
`

`

`(19) The Japanese Patent Office (JP)
`
`
`
`
`(51) Int. Cl.
`
`
`
`
`
`(12) PATENT APPLICATION LAID-OPEN PUBLICATION (A)
`(11) Laid-Open Publication Number:
`No. 2006-14564
`(P2006-14564A)
`(43) Laid-Open Date: January 12, 2006
`
`Themed code (Ref)
`
`FI
`
`
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`
`
`
`(total 22 pages)
`Number of Claims: 25 OL
`Request for Examination (not filed)
`(71) Applicant(s): NISSAN MOTOR CO., LTD., 2
`(21) Application Number: 2004-191968
`Takaracho, Kanagawa-Ku, Yokohama City, Japan,
`(22) Filing Date: June 29, 2004
`000003997
`
`(74) Patent Attorney 100119644, AYATA Masao
`(74) Patent Attorney 100105153, ASAKURA Go
`(72) Inventor(s): TAN Naruhiko, WATANABE Jun;
`SHIMIZU Hirofumi, c/o NISSAN MOTOR CO., LTD., 2
`Takaracho, Kanagawa-Ku, Yokohama City, Japan
`
`
`(54) [Title of Invention] STATOR COOLING STRUCTURE OF DISC-SHAPED ROTARY ELECTRIC MACHINE
`
`
`(57) [Abstract]
`[Task]
`To provide a stator cooling structure of a
`disc-shaped rotary electric machine that can increase
`continuous output power considerably by improving
`cooling efficiency without deteriorating motor
`efficiency.
`[Solution] In a disc-shaped rotary electric machine
`comprising a rotor 2 having permanent magnets 9
`disposed thereon and a stator 3 having stator cores 11
`and stator coils 12, the rotor 2 and the stator 3 being
`arranged in an axial direction, coil coolant passages 15,
`16 are formed in a resin mold 14 molded so as to
`envelop the stator cores 11, wherein the coil coolant
`passages 15, 16 are arranged on an inner circumference
`and an outer circumference of the stator cores 12 ,
`respectively, and each have one coolant inlet 17, 18 and
`one coolant outlet 19, 20 such that coolant is directed to
`the coil coolant passages 15, 16 to cool the stator coils
`12.
`[Selected Drawing]
`
`
`
`FIG. 1
`
`
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`Am. Honda v. IV II - IPR2018-00349
`PET_HONDA_1013-0002
`
`

`

`JP 2006-14564 (P2006-14564A)
`
`(2)
`
`
`[Claims]
`[Claim 1]
`A stator cooling structure of a disc-shaped rotary electric machine comprising a rotor having permanent magnets
`disposed thereon and a stator having stator cores and stator coils, the rotor and the stator being arranged in the axial
`direction thereof, wherein:
`a coil coolant passage is formed in a resin mold molded so as to envelop the stator cores; and
`the coil coolant passage is arranged on at least one of the inner circumference and/or the outer circumference of the
`stator cores, and has one or more coolant inlets and one or more coolant outlets, such that coolant is directed to the
`coil coolant passage to cool the stator coils.
`[Claim 2]
`The stator cooling structure of the disc-shaped rotary electric machine according to claim 1, wherein the coil
`coolant passage is configured in an O-shape where the coil coolant passage is communicatively connected along at
`least one of the inner circumference and/or the outer circumference of the stator cores over at least one entire
`circumference.
`[Claim 3]
`The stator cooling structure of the disc-shaped rotary electric machine according to claim 1, wherein the coil
`coolant passage is configured in a C-shape where the coil coolant passage is communicatively connected along at least
`one of the inner circumference and/or the outer circumference of the stator cores over at least one entire
`circumference.
`[Claim 4]
`The stator cooling structure of the disc-shaped rotary electric machine according to any one of claims 1 to 3,
`wherein the coil coolant passage is constituted of inner circumferential side coil coolant passage(s) and outer
`circumferential side coil coolant passage(s).
`[Claim 5]
`The stator cooling structure of the disc-shaped rotary electric machine according to claim 4, wherein a direction of
`flow of the coolant in the inner circumferential side coil coolant passage(s) and the outer circumferential side coil
`coolant passage(s) is set opposite.
`[Claim 6]
`The stator cooling structure of the disc-shaped rotary electric machine according to claim 4 or 5, wherein the
`coolant passages include a plurality of outer circumferential side coil coolant passages arranged in a circumferential
`direction.
`[Claim 7]
`The stator cooling structure of the disc-shaped rotary electric machine according to any one of claims 4 to 6,
`wherein the number of the outer circumferential side coil coolant passages is greater than that of the inner
`circumferential side coil coolant passage(s).
`[Claim 8]
`The stator cooling structure of the disc-shaped rotary electric machine according to any one of claims 1 to 7,
`wherein the coil coolant passages include an outer circumferential side coil coolant passage formed by a meandering
`coolant passage.
`[Claim 9]
`The stator cooling structure of the disc-shaped rotary electric machine according to any one of claims 1 to 8,
`wherein the coil coolant passages include a plurality of coolant passages configured such that the closer the coolant
`passages are to the free axial end of the stator cores, the larger the flow passage areas the coolant passages have.
`[Claim 10]
`The stator cooling structure of the disc-shaped rotary electric machine according to any one of
`claims 1 to 9,
`
`Am. Honda v. IV II - IPR2018-00349
`PET_HONDA_1013-0003
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`

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`JP 2006-14564 (P2006-14564A)
`
`(3)
`
`wherein the coil coolant passages include a plurality of coolant passages, among which the coolant passages located
`close to the free axial end of the stator cores are meandering coolant passages.
`[Claim 11]
`The stator cooling structure of the disc-shaped rotary electric machine according to any one of claims 1 to 10,
`wherein:
`a case coolant passage is provided in a motor housing case that supports the stator; and
`the case coolant passage is configured to be communicatively connected with the coil coolant passages.
`[Claim 12]
`The stator cooling structure of the disc-shaped rotary electric machine according to claim 11, wherein the case
`coolant passage and the coil coolant passage are both configured in O-shapes.
`[Claim 13]
`The stator cooling structure of the disc-shaped rotary electric machine according to claim 11, wherein the case
`coolant passage and the coil coolant passage are both configured in C-shapes.
`[Claim 14]
`The stator cooling structure of the disc-shaped rotary electric machine according to any one of claims 11 to 13,
`wherein the case coolant passage and the coil coolant passage are communicatively connected in series.
`[Claim 15]
`The stator cooling structure of the disc-shaped rotary electric machine according to any one of claims 11 to 14,
`wherein the case coolant passage and the coil coolant passage are configured to set the order of flow of the coolant
`such that the coolant flows from the coil coolant passage to the case coolant passage.
`[Claim 16]
`The stator cooling structure of the disc-shaped rotary electric machine according to any one of claims 11 to 13,
`wherein the case coolant passage and the coil coolant passage are communicatively connected in parallel.
`[Claim 17]
`The stator cooling structure of the disc-shaped rotary electric machine according to any one of claims 11 to 16,
`wherein the inlet of the case coolant passage and the inlet of the coil coolant passage are arranged to have a phase
`difference in the circumferential direction.
`[Claim 18]
`The stator cooling structure of the disc-shaped rotary electric machine according to any one of claims 11 to 16,
`wherein the case coolant passage is provided with fins.
`[Claim 19]
`The stator cooling structure of the disc-shaped rotary electric machine according to any one of claims 1 to 18,
`wherein the coil coolant passage is formed by a resin mold molded so as to envelop the stator cores.
`[Claim 20]
`The stator cooling structure of the disc-shaped rotary electric machine according to any one of claims 1 to 18,
`
`Am. Honda v. IV II - IPR2018-00349
`PET_HONDA_1013-0004
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`

`

`JP 2006-14564 (P2006-14564A)
`
`(4)
`
`wherein the coil coolant passage is configured to have a groove formed when molding the resin and a coolant
`passage closure member that gradually closes the groove forming an inlet and an outlet for the coolant.
`[Claim 21]
`The stator cooling structure of the disc-shaped rotary electric machine according to any one of claims 1 to 18,
`wherein the coil coolant passage is formed by a flat-shaped highly thermally conductive member that is embedded in
`the resin mold molded so as to envelop the stator cores.
`[Claim 22]
`The stator cooling structure of the disc-shaped rotary electric machine according to any one of claims 1 to 21,
`wherein the coil coolant passage has a heat receiving body integrated therewith.
`[Claim 23]
`The stator cooling structure of the disc-shaped rotary electric machine according to claim 22, wherein the heat
`receiving body is formed to extend over the entire circumferential direction of the coil coolant passage.
`[Claim 24]
`The stator cooling structure of the disc-shaped rotary electric machine according to claim 22, wherein the heat
`receiving body is formed to extend in a radial direction of the coil coolant passage.
`[Claim 25]
`The stator cooling structure of the disc-shaped rotary electric machine according to any one of claims 1 to 24,
`wherein the coolant outlet and the coolant inlet are configured such that a coolant outlet area is larger than a coolant
`inlet area.
`[Detailed Description of the Invention]
`[0001]
`The present invention belongs to a technical field of a stator cooling structure of a disc-shaped rotary electric
`machine having a stator and a rotor arranged to face each other in the axial direction.
`[Background Art]
`[0002]
`An interior permanent magnet synchronous motor (IPMSM) which includes permanent magnets embedded in the
`rotor and a surface permanent magnet synchronous motor (SPMSM) which includes permanent magnets attached on
`the rotor surface have a small loss, a high efficiency, and a large output power (reluctance torque can be used in
`addition to magnet torque), and for such reasons, are being used in a wider area of applications such as a motor for
`electric cars, a motor for hybrid cars, etc.
`[0003]
`Of such permanent magnet synchronous motors, a disc-shaped motor which has a stator and a rotor arranged to face
`each other in an axial direction can have a reduced thickness and is used in applications where there is a restriction on
`the layout. Also, it is known to introduce oil (coolant) into an interior of the disc-shaped motor for cooling (see Patent
`Document 1, for example).
`[Patent Document 1] JPH10-243617A
`[Disclosure of the Invention]
`[Tasks to be Accomplished by the Invention]
`[0004]
`However, in the conventional disc-shaped motor, the stator and the rotor are disposed to have a very small space
`(gap) therebetween to improve the magnetic performance, and therefore, there is a problem that the introduced coolant
`flows into the gap and increases the friction loss, and hence, the motor efficiency is deteriorated.
`
`Am. Honda v. IV II - IPR2018-00349
`PET_HONDA_1013-0005
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`

`

`JP 2006-14564 (P2006-14564A)
`
`(5)
`
`
`[0005]
`The present invention has been made in view of the above problems, and an object thereof is to provide a stator
`cooling structure of a disc-shaped rotary electric machine that can increase continuous output power considerably by
`improving cooling efficiency without deteriorating the motor efficiency.
`[Means to Accomplish the Task]
`[0006]
`To achieve the above object, according to the present invention, in a disc-shaped rotary electric machine comprising
`a rotor having permanent magnets disposed thereon and a stator having stator cores and stator coils, the rotor and the
`stator being arranged in the axial direction thereof,
`a coil coolant passage is formed in a resin mold molded so as to envelop the stator core, and
`the coil coolant passage is arranged on at least one of the inner circumference and/or the outer circumference of the
`stator cores, and has one or more coolant inlets and one or more coolant outlets, such that coolant is directed to the
`coil coolant passage to cool the stator coils.
`[Effect of the Invention]
`[0007]
`Thereby, in the stator cooling structure of the disc-shaped rotary electric machine according to the present invention,
`because the coil coolant passage is formed in a resin mold, the distance to the stator coils, which are heat generating
`members, can be reduced, and the cooling efficiency is improved compared to air cooling. In addition, because the
`coolant for cooling the stator coils flows in the sealed coil coolant passage and does not flow into the gap between the
`rotor and the stator, an increase in the friction is avoided. As a result, the continuous output power can be increased
`considerably owing to improvement of the cooling efficiency without deteriorating the motor efficiency.
`[Best Mode for Carrying Out the Invention]
`[0008]
`In the following, the best mode for implementing a stator cooling structure of a disc-shaped rotary electric machine
`of the present invention will be described based on Embodiments 1 to 21 illustrated in the drawings.
`[Embodiment 1]
`[0009]
`First, a structure will be described.
`FIG. 1 is an overall cross-sectional view showing a disc-shaped rotary electric machine to which a stator cooling
`structure of Embodiment 1 is applied. The disc-shaped rotary electric machine includes a rotary shaft 1, a rotor 2, a
`stator 3, and a rotary electric machine case 4 (motor housing case), and the rotary electric machine case 4 is
`constituted of a front side case 4a, a rear side case 4b, and an outer circumference case 4c bolted to both the side cases
`4a, 4b.
`[0010]
`The rotary shaft 1 is rotatably supported by a first bearing 5 provided in the front side case 4a and a second bearing
`6 provided in the rear side case 4b.
`[0011]
`The rotor 2 includes a rotor base 8 made of an electromagnetic steel plate (ferromagnetic material) and secured to
`the rotary shaft 1, and a plurality of permanent magnets 9 partially embedded in a surface facing the stator 3, where
`the rotor base 8 is secured to the rotary shaft 1 such that a reaction force is generated by the permanent magnets 9 in
`response to a rotating magnetic flux provided by the stator 3 and thereby the rotor rotates with the rotary shaft 1 at the
`center. The plurality of permanent magnets 9 are arranged such that adjacent surface magnetic poles (N pole, S pole)
`are different from each other. It is to be noted here that there is a clearance called a gap 10 between the rotor 2 and the
`stator 3, and thus, they do not contact each other.
`[0012]
`The stator 3 is secured to the rear side case 4b, and includes stator cores 11, stator coils 12, and a back core 13.
`
`Am. Honda v. IV II - IPR2018-00349
`PET_HONDA_1013-0006
`
`

`

`JP 2006-14564 (P2006-14564A)
`
`(6)
`
`The stator coils 12 are wound around the stator cores 11, respectively, via electrical insulation paper or electrical
`insulator not shown in the drawings. The stator 3 is held by the rear side case 4b via the back core 13 thereof.
`[0013]
`FIG. 2 is a cross-sectional view of a stator to which the stator cooling structure of the disc-shaped rotary electric
`machine of Embodiment 1 is applied, and description will now be made of the stator cooling structure of Embodiment
`1 based on FIGS. 1 and 2.
`[0014]
`The stator cooling structure of Embodiment 1 includes coil coolant passages 15, 16 formed in a resin mold 14
`molded so as to envelop the stator cores 11. The coil coolant passages 15, 16 are arranged on the inner circumference
`and the outer circumference of the stator cores 12 , respectively, and each have one coolant inlet 17, 18 and one
`coolant outlet 19, 20 such that coolant is directed to the coil coolant passages 15, 16 to cool the stator coils 12.
`[0015]
`The coil coolant passages 15, 16 include an inner circumferential side coil coolant passage 15 and an outer
`circumferential side coil coolant passage 16 respectively formed by embedding highly thermally conductive members
`21, 22 into the resin mold 14 molded so as to envelop the stator cores 11, where the inner circumferential side coil
`coolant passage 15 is provided with the coolant inlet 17 and the coolant outlet 19, while the outer circumferential side
`coil coolant passage 16 is provided with the coolant inlet 18 and the coolant outlet 20.
`[0016]
`As shown in FIG. 2, the coil coolant passages 15, 16 are each configured in an O-shape where each coil coolant
`passage 15, 16 extends continuously along the corresponding one of the inner circumference and the outer
`circumference of the stator cores 11 over at least one entire circumference.
`[0017]
`Next, the operation will be described.
`When the rotary electric machine is operated continuously at high output power, heat is generated from the stator
`due to copper loss and core loss, and the temperature of the stator coils rises with time. In addition, the permanent
`magnets on the rotor generate heat due to an eddy current induced in each magnet, and thus, the ambient temperature
`inside the rotary electric machine also rises. Therefore, it is necessary to cool the stator coils which generate heat the
`most.
`[0018]
`In a case where ordinary air cooling is adopted in the rotary electric machine to deal with this, because the heat
`dissipation is poor, the temperature of the stator coils cannot be prevented from rising in the rotary electric machine
`operated at a high output power, resulting in a shorter continuous output time. On the other hand, in a case where
`coolant is introduced into the rotary electric machine for cooling (for example, JPH10-243617A), the coolant flows
`into the gap between the rotor and the stator and increases the friction loss, which deteriorates the motor efficiency.
`[0019]
`In contrast, in Embodiment 1, by forming the coil coolant passages 15, 16 in the resin mold 14 molded so as to
`envelop the stator cores 11, the continuous output power is increased considerably owing to improvement of the
`cooling efficiency without deteriorating the motor efficiency.
`[0020]
`Specifically, as shown in FIG. 2, the coolant is introduced from the coolant inlet 17, passes through the inner
`circumferential side coil coolant passage 15 formed by the highly thermally conductive member 21 embedded in the
`resin mold during the molding, and reaches the coolant outlet 19. At the same time, the coolant is introduced from the
`coolant inlet 18, passes through the outer circumferential side coil coolant passage 16 formed by the highly thermally
`conductive member 22 embedded in the resin mold during the molding, and reaches the coolant outlet 20.
`Thereby, the distance between the coolant and the stator coils 12, which are heat generating members, can be
`reduced, and this reduces the thermal resistance and improves the cooling efficiency. Thus, compared to air cooling,
`the cooling efficiency is improved considerably, and therefore, the continuous output power can be increased
`considerably.
`Further, the coolant for cooling the stator coils 12 flows through the sealed coil coolant passages 15, 16 and does
`not flow into the gap 10 with respect to the rotor 2, and hence, an increase in the friction is avoided.
`[0021]
`
`Am. Honda v. IV II - IPR2018-00349
`PET_HONDA_1013-0007
`
`

`

`JP 2006-14564 (P2006-14564A)
`
`(7)
`
`In Embodiment 1, because one coolant inlet and one coolant outlet are provided to each coolant passage, compared
`to a case where multiple coolant inlets and multiple coolant outlets are provided, the flow rate of the coolant for
`cooling the stator coils 12 can be made more uniform, and therefore, the cooling efficiency is improved. Further,
`unlike the conventional radial gap rotary electric machine, problems such as a reduction of the motor performance due
`to an increase in the gap between the rotor and the stator, and deterioration of the cooling efficiency caused by an
`increase in the thermal resistance due to intervention of the stator core between the stator coil and the coolant passage
`are avoided.
`[0022]
`Next, effects will be described.
`In the stator cooling structure of the disc-shaped rotary electric machine of Embodiment 1, the following effects can
`be obtained.
`[0023]
`(1) In the disc-shaped rotary electric machine comprising the rotor 2 having the permanent magnets 9 disposed
`thereon and the stator 3 having the stator cores 11 and the stator coils 12, the rotor 2 and the stator 3 being arranged in
`the axial direction, the coil coolant passages 15, 16 are formed in the resin mold 14 molded so as to envelop the stator
`cores 11, wherein the coil coolant passages 15, 16 are arranged on the inner circumference and the outer
`circumference of the stator cores 12, respectively, and each have one coolant inlet 17, 18 and one coolant outlet 19, 20
`such that the coolant is directed to the coil coolant passages 15, 16 to cool the stator coils 12. Therefore, it is possible
`to increase the continuous output power considerably by improving the cooling efficiency without decreasing the
`motor efficiency.
`[0024]
`(2) Because the shape of the coil coolant passages 15, 16 are each provided in an O-shape wherein each coil coolant
`passage extends continuously along the the inner circumference and the outer circumference of the stator cores 11
`over at least one entire circumference, and therefore, non-uniformity of the cooling capacity in the stator
`circumferential direction caused by temperature gradient of the coolant due to heat absorption is reduced, whereby the
`cooling efficiency can be improved further.
`[0025]
`(3) Because the coil coolant passage is configured from the inner circumferential side coil coolant passage 15 and
`the outer circumferential side coil coolant passage 16, the coolant is distributed over the entire circumference of the
`stator cores 11 and a variation in the cooling capacity is suppressed, whereby the cooling efficiency can be improved
`further.
`[Embodiment 2]
`[0026]
`Embodiment 2 is an example in which the coil coolant passages 15, 16 are configured in a C-shape, as opposed to
`Embodiment 1 in which the coil coolant passages 15, 16 are configured in an O-shape.
`[0027]
`Specifically, as shown in FIG. 3, the inner circumferential side coil coolant passage 15 and the outer circumferential
`side coil coolant passage 16 are each configured in a C-shape wherein they extend continuously along the inner
`circumference and the outer circumference of the stator cores 11, respectively, over less than an entire circumference,
`and each coil coolant passage 15, 16 is provided with a coolant inlets 17, 18 and a coolant outlets 19, 20 at the
`respective ends thereof where the continuous extension is interrupted. The other structures are the same as those of
`Embodiment 1, and therefore, the corresponding structures are denoted by the same reference numerals and
`description thereof is omitted.
`[0028]
`Next, the operation will be described. Each of the inner circumferential side coil coolant passages 15 and the outer
`circumferential side coil coolant passages 16 of Embodiment 2 are not bifurcated unlike in Embodiment 1, and the
`coolant flows in one direction from the end where the coolant inlets 17, 18 are formed to the end where the coolant
`outlets 19, 20 are formed, and therefore, the flow velocity of the coolant is not lowered. The other operations are the
`same as those of Embodiment 1.
`[0029]
`Next, effects will be described. In the stator cooling structure of the disc-shaped rotary electric machine of
`Embodiment 2, the following effects can be obtained in addition to the effects (1) and (3) of Embodiment 1.
`[0030]
`(4) Because the inner circumferential side coil coolant passage 15 and the outer circumferential side coil coolant
`passage 16 are each configured in a C-shape where the coil coolant passage extends continuously along inner
`circumference and the outer circumference of the stator cores 11 over less than an entire circumference, the flow
`velocity is raised without an increase in the flow rate, whereby the cooling efficiency can be improved.
`
`Am. Honda v. IV II - IPR2018-00349
`PET_HONDA_1013-0008
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`

`

`JP 2006-14564 (P2006-14564A)
`
`(8)
`
`
`[Embodiment 3]
`[0031]
`Embodiment 3 is an example in which the direction of flow of the coolant is opposite in respect of the inner and
`outer circumference side coil coolant passages.
`[0032]
`Specifically, in the example in which the coil coolant passages 15, 16 are each an O-shape, as shown in FIG. 4, and
`set such that the flow direction in the inner circumferential side coil coolant passage 15 is from up to down, while the
`flow direction in the outer circumferential side coil coolant passage 16 is from down to up, whereby the direction of
`flow of coolant is opposite in the respective coil coolant passages.
`[0033]
`In the example in which the coil coolant passages 15, 16 are each in a C-shape, as shown in FIG. 5, the flow
`direction in the inner circumferential side coil coolant passage 15 is counterclockwise as viewed in the drawing, while
`the flow direction in the outer circumferential side coil coolant passage 16 is clockwise as viewed in the drawing,
`whereby the direction of flow of coolant is opposite in the respective coil coolant passages. The other structures are
`the same as those of Embodiment 1 or Embodiment 2, and therefore, the corresponding structures are denoted by the
`same reference numerals and description thereof is omitted.
`[0034]
`Next, the operation will be described. As the direction of flow of the coolant is opposite in respect of the inner
`circumferential side coil coolant passage 15 and the outer circumferential side coil coolant passage 16, non-uniformity
`of the cooling capacity in the stator circumferential direction caused by a temperature gradient of the coolant due to
`heat absorption is reduced. The other operations are the same as those of Embodiments 1 and 2, and thus, description
`thereof is omitted.
`[0035]
`Next, effects will be described. In the stator cooling structure of the disc-shaped rotary electric machine of
`Embodiment 3, the following effects can be obtained in addition to the effects of Embodiments 1 and 2.
`[0036]
`(5) As the direction of flow of the coolant is opposite in respect of the inner circumferential side coil coolant
`passage 15 and the outer circumferential side coil coolant passage 16, non-uniformity of the cooling capacity in the
`stator circumferential direction caused by a temperature gradient of the coolant due to heat absorption is reduced,
`whereby the cooling efficiency can be improved.
`[Embodiment 4]
`[0037]
`Embodiment 4 is an example in which a plurality of outer circumferential side coil coolant passages are arranged in
`the circumferential direction.
`[0038]
`Specifically, as shown in FIG. 6, as the coil coolant passages, one C-shaped inner circumferential side coil coolant
`passage 15 and two C-shaped outer circumferential side coil coolant passages 16, 16 arranged on the same
`circumference are provided. For the outer circumferential side coil coolant passages 16, 16, two coolant inlets 18, 18
`and two coolant outlets 20, 20 are provided, and the outer circumferential side coil coolant passages 16, 16 are
`connected in parallel to each other. The other structures are the same as those of Embodiment 1, and therefore, the
`corresponding structures are denoted by the same reference numerals and description thereof is omitted.
`[0039]
`Next, the operation will be described. The length of contact of each stator coil 12 with the coolant passage is larger
`on the outer circumferential side than on the inner circumferential side, and typically, a larger amount of heat is
`generated on the outer circumferential side of the stator coil 12 than on the inner circumferential side. In such a case,
`by providing the circumferentially-arranged two outer circumferential side coil coolant passages 16, 16 on the outer
`circumferential side to increase the cooling capacity as compared to Embodiments 1 to 3, it is possible to reduce
`non-uniformity of the cooling capacity in the stator radial direction caused between the inner and outer circumferential
`sides of the stator 3.
`[0040]
`Next, effects will be described. In the stator cooling structure of the disc-shaped rotary electric machine of
`Embodiment 4, the following effects can be obtained in addition to the effects of Embodiments 1 to 3.
`[0041]
`(6) Because a plurality of outer circumferential side coil coolant passages 16, 16 are arranged in the circumferential
`direction, non-uniformity of the cooling capacity in the stator radial direction caused between the inner and outer
`circumferential sides of the stator 3 is reduced, whereby the cooling efficiency can be improved.
`[Embodiment 5]
`[0042]
`
`Am. Honda v. IV II - IPR2018-00349
`PET_HONDA_1013-0009
`
`

`

`JP 2006-14564 (P2006-14564A)
`
`(9)
`
`Embodiment 5 is an example in which the number of the outer circumferential side coil coolant passages is greater
`than the number of the inner circumferential side coil coolant passage(s).
`[0043]
`Specifically, as shown in FIG. 7, as the coil coolant passages, one inner circumferential side coil coolant passage 15
`and two outer circumferential side coil coolant passages 16, 16 are arranged. The other structures are the same as
`those of Embodiment 1, and therefore, the corresponding structures are denoted by the same reference numerals and
`description thereof is omitted.
`[0044]
`Next, the operation will be described. The length of each stator coil 12 in contact with the coolant passage is larger
`on the outer circumferential side than on the inner circumferential side, and typically, a larger amount of heat is
`generated on the outer circumferential side of the stator coil 12 than on the inner circumferential side. In such a case,
`by providing two outer circumferential side coil coolant passages 16, 16 on the outer circumferential side and one
`inner circumferential side coil coolant passage 15 on the inner circumferential side to thereby increase the cooling
`capacity on the outer circumferential side than on the inner circumferential side, it is possible to reduce
`non-uniformity of the cooling capacity in the stator radial direction caused between the inner and outer circumferential
`sides of the stator 3. Further, as compared to Embodiments 1 to 4, the number of coolant passages as a whole is
`increased, whereby the cooling area is increased.
`[0045]
`Next, effects will be described. In the stator cooling structure of the disc-shaped rotary electric machine of
`Embodiment 5, the following effects can be obtained in addition to the effects of Embodiments 1 to 3.
`[0046]
`(7) Because configuration is made such that the number of the outer circumferential side coil coolant passages 16,
`16 is greater than the number of the inner circumferential side coil coolant passage(s) 15, non-uniformity of the
`cooling capacity in the stator radial direction caused between the inner and outer circumferential sides of the stator 3
`is reduced and the cooling area is increased, whereby the cooling efficiency can be improved.
`[0047]
`It is to be noted that though in Embodiment 5, an example provided with two outer circumferential side coil coolant
`passages 16, 16 and one inner circumferential side coil coolant passage 15 was shown, the number of the coolant
`passages is not limited so long as a larger number of coolant passages are provided on the outer circumferential side
`than on the inner circumferential side, such as three or more outer circumferential side coil coolant passages and two
`or more inner circumferential side coil coolant passages, for example.
`[Embodiment 6]
`[0048]
`Embodiment 6 is an example in which the outer circumferential side coil coolant passage is formed of a meandering
`coolant passage.
`[0049]
`Specifically, as seen in View A, the outer circumferential side coil coolant passage 16 is formed of a meanderi