JP2020090898A - Electric supercharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent oil supplied to a bearing from leaking into an impeller chamber. A seal ring 44 is a non-magnetic material. Therefore, for example, as compared with the case where the seal ring 44 is a magnetic material, it is suppressed that the seal ring 44 is attracted toward the electric motor 19 due to the magnetic force generated by the magnetic field generated during the driving of the electric motor 19. Ru. Therefore, in a state where the inner surface of the mounting groove 43a and the seal ring 44 are in contact with each other, the seal collar 43 rotates integrally with the rotating shaft 17, and the seal ring 44 wears, so that the mounting groove 43a and the seal ring 44 are in contact with each other. It is possible to avoid a problem that the gap between the two is larger than the expected gap. As a result, it is suppressed that the oil supplied to the first bearing 31 passes through the gap between the mounting groove 43a and the seal ring 44 from the bearing holding hole 40h. [Selection diagram] FIG. 4

Description

The present invention relates to an electric supercharger in which an impeller rotates due to rotation of a rotary shaft that accompanies driving of an electric motor.

An electric motor that rotates a rotating shaft is housed in the housing of the electric supercharger. An impeller is connected to the axial end of the rotary shaft. A motor chamber that houses the electric motor and an impeller chamber that houses the impeller chamber are formed in the housing. Further, the housing has a bearing holding wall which is arranged between the motor chamber and the impeller chamber and has a bearing holding hole for holding the bearing. The bearing held in the bearing holding hole rotatably supports the portion of the rotating shaft between the electric motor and the impeller with respect to the housing. Further, an insertion hole through which the rotary shaft is inserted is formed in a portion of the bearing holding wall closer to the impeller chamber than the bearing holding hole. In the electric supercharger, the impeller rotates due to the rotation of the rotating shaft that accompanies the driving of the electric motor.

The bearing that supports the rotating shaft of an electric supercharger tends to reach a high temperature due to the rotating shaft that rotates at high speed, and seizure will occur if lubrication is insufficient.Therefore, supplying oil to the bearing lubricates the bearing and cools it. It is necessary to. Then, for example, in the electric supercharger of Patent Document 1, a cylindrical seal collar that rotates integrally with the rotary shaft is arranged inside the insertion hole, and an annular mounting groove formed on the outer peripheral surface of the seal collar is arranged. A seal ring is mounted, and the seal ring seals between the mounting groove and the insertion hole. According to this, it is possible to prevent the oil supplied to the bearing from leaking from the bearing holding hole to the impeller chamber through the insertion hole.

JP, 2017-210879, A

By the way, when the seal ring is formed of, for example, a magnetic material, the seal ring is attracted toward the electric motor by the magnetic force generated by the magnetic field generated during driving of the electric motor, and the seal ring is attached to the mounting groove. The inner surface may come into contact with a portion located on the electric motor side. Then, the seal collar rotates integrally with the rotary shaft in a state where the seal ring is in contact with the portion of the inner surface of the mounting groove located on the electric motor side, and the portion of the seal ring on the electric motor side is worn. I will end up. Then, the gap between the mounting groove and the seal ring becomes larger than the expected gap, and the oil supplied to the bearing passes through the gap between the mounting groove and the seal ring from the bearing holding hole, and the oil flows into the impeller chamber. There is a risk of leakage.

The present invention has been made to solve the above problems, and an object thereof is to provide an electric supercharger capable of suppressing the oil supplied to a bearing from leaking into an impeller chamber. It is in.

An electric supercharger for solving the above-mentioned problems includes a housing, a rotary shaft rotatably supported by the housing, an electric motor housed in the housing and rotating the rotary shaft, and a shaft of the rotary shaft. An impeller connected to an end portion in a direction, a motor chamber formed in the housing and accommodating the electric motor, an impeller chamber formed in the housing and accommodating the impeller, and the motor chamber. A bearing holding wall having a bearing holding hole that is arranged between the impeller chamber and holds a bearing that rotatably supports a portion of the rotating shaft between the electric motor and the impeller with respect to the housing; An insertion hole formed in a portion of the bearing holding wall closer to the impeller chamber than the bearing holding hole and through which the rotation shaft is inserted; and an insertion hole arranged inside the insertion hole and integrated with the rotation shaft. An electric motor equipped with a cylindrical seal collar that rotates in a horizontal direction, and a seal ring that is mounted in an annular mounting groove formed on the outer peripheral surface of the seal collar and that seals between the mounting groove and the insertion hole. In the supercharger, the seal ring is a non-magnetic body.

According to this, compared with the case where the seal ring is a magnetic body, for example, it is possible to suppress the seal ring from being drawn toward the electric motor due to the magnetic force generated by the magnetic field generated during driving of the electric motor. Therefore, when the inner surface of the mounting groove and the seal ring are in contact with each other, the seal collar rotates integrally with the rotating shaft, and the seal ring is worn away. It is possible to avoid the problem that the gap becomes larger than the existing gap. As a result, the oil supplied to the bearing is prevented from passing through the gap between the mounting groove and the seal ring from the bearing holding hole, so that the oil supplied to the bearing is prevented from leaking into the impeller chamber. Can be suppressed.

In the above electric supercharger, the seal ring may be made of austenitic stainless steel. Austenitic stainless steel is a particularly suitable material for making the seal ring a non-magnetic material.

According to the present invention, it is possible to prevent the oil supplied to the bearing from leaking into the impeller chamber.

The side sectional view showing the electric supercharger in an embodiment. Sectional drawing which expands and shows the 1st bearing side in an electric supercharger. Sectional drawing which expands and shows the 2nd bearing side in an electric supercharger. Sectional drawing which expands and shows the periphery of a seal collar and a seal ring. Sectional drawing which expands and shows a part of electric supercharger.

An embodiment in which the electric supercharger is embodied will be described below with reference to FIGS. 1 to 5. The electric supercharger of the present embodiment is installed in the engine room of an automobile and is used to compress and supply air as a fluid to the engine.

As shown in FIG. 1, the housing 11 of the electric supercharger 10 includes a motor housing 12, a compressor housing 13, a plate 14, and a cover 15. The motor housing 12, the compressor housing 13, the plate 14, and the cover 15 are made of metal, for example, aluminum.

The motor housing 12 has a bottomed cylindrical shape having a disk-shaped bottom wall 12a and a peripheral wall 12b extending from the outer peripheral portion of the bottom wall 12a in a cylindrical shape. Therefore, the housing 11 has the cylindrical peripheral wall 12b. A through hole 12h is formed in the center of the bottom wall 12a. The cover 15 has a flat plate shape and closes the through hole 12h by being attached to the outer surface of the bottom wall 12a by a bolt 15a.

As shown in FIG. 2, the plate 14 includes a disc-shaped seal plate 40 and a disc-shaped retainer 41. The seal plate 40 is connected to an end of the peripheral wall 12b of the motor housing 12 opposite to the bottom wall 12a. The seal plate 40 has a cylindrical fitting portion 40f protruding from the center of the end surface 40a of the seal plate 40 on the motor housing 12 side. The seal plate 40 is connected to the motor housing 12 in a state where the fitting portion 40f is fitted into the opening 12c on the opposite side of the bottom wall 12a of the motor housing 12. The fitting portion 40f closes the opening 12c of the motor housing 12.

A bearing holding hole 40h is formed in the fitting portion 40f of the seal plate 40. An annular engaging portion 40e projects from a portion of the inner peripheral surface of the bearing holding hole 40h that is farthest from the bottom wall 12a of the motor housing 12.

The compressor housing 13 is connected to the seal plate 40 on the side opposite to the motor housing 12. The compressor housing 13 has a substantially disc-shaped bottom wall 13a and a peripheral wall 13b extending from the outer peripheral portion of the bottom wall 13a in a tubular shape. The opening on the side of the peripheral wall 13b opposite to the bottom wall 13a is closed by a seal plate 40.

As shown in FIG. 1, the electric supercharger 10 includes a rotating shaft 17 rotatably supported by a housing 11. One end of the rotary shaft 17 penetrates the plate 14 and projects into the compressor housing 13. An impeller 18 is connected to one end of the rotary shaft 17. Therefore, the impeller 18 is connected to the axial end of the rotary shaft 17. The other end of the rotating shaft 17 is located inside the through hole 12h.

The compressor housing 13 includes an intake port 13c for intake of air (fresh air), an impeller chamber 13d communicating with the intake port 13c and accommodating an impeller 18, and a discharge chamber for ejecting air compressed by the impeller 18. 13e and the diffuser flow path 13f which connects the impeller chamber 13d and the discharge chamber 13e. Therefore, the impeller chamber 13d that houses the impeller 18 is formed in the housing 11. The plate 14 partitions the impeller chamber 13d.

An electric motor 19 for rotating the rotating shaft 17 is housed in the motor housing 12. The electric motor 19 is housed in a motor chamber 20 that is a space surrounded by the bottom wall 12 a and the peripheral wall 12 b of the motor housing 12 and the plate 14. Therefore, a motor chamber 20 that houses the electric motor 19 is formed in the housing 11. The plate 14 is a part of the housing 11 and is arranged between the motor chamber 20 and the impeller chamber 13d. The plate 14 functions as a partition wall that partitions the motor chamber 20 and the impeller chamber 13d.

The electric motor 19 includes a tubular stator 21 and a rotor 22 arranged inside the stator 21. A coil 23 is wound around the stator 21. The rotor 22 rotates integrally with the rotating shaft 17 by supplying a current to the coil 23.

The stator 21 includes a stator core 21a fixed to the inner peripheral surface of the peripheral wall 12b of the motor housing 12, a first coil end 23a and a second coil end 23a protruding from both end surfaces of the stator core 21a that are located in the axial direction of the rotating shaft 17. 23b. The first coil end 23a projects from an end surface of the stator core 21a located on the plate 14 side in the axial direction of the rotating shaft 17. The second coil end 23b projects from the end surface of the stator core 21a located on the bottom wall 12a side of the motor housing 12 in the axial direction of the rotating shaft 17. The first coil end 23 a and the second coil end 23 b are a part of the coil 23.

As shown in FIG. 2, the electric supercharger 10 includes a first bearing 31 as a bearing that rotatably supports a portion of the rotating shaft 17 between the electric motor 19 and the impeller 18 with respect to the housing 11. There is. The first bearing 31 is held in the bearing holding hole 40h. Therefore, the bearing holding hole 40h holds the first bearing 31 that rotatably supports the portion of the rotating shaft 17 between the electric motor 19 and the impeller 18 with respect to the housing 11. The plate 14 functions as a bearing holding wall having the bearing holding hole 40h. A portion of the rotating shaft 17 between the electric motor 19 and the impeller 18 is rotatably supported by the seal plate 40 via the first bearing 31.

The first bearing 31 includes a first inner ring 31a fixed to the outer peripheral surface of the rotating shaft 17, a first outer ring 31b arranged outside the first inner ring 31a, a first inner ring 31a and a first outer ring 31b. It is an angular contact ball bearing having a plurality of spherical first rolling elements 31c arranged therebetween. The first inner ring 31 a is press fitted onto the outer peripheral surface of the rotating shaft 17. The first outer ring 31b is press fitted into the inner peripheral surface of the bearing holding hole 40h.

As shown in FIG. 3, the electric supercharger 10 includes a second bearing 32 that rotatably supports a portion of the rotating shaft 17 on the opposite side of the electric motor 19 to the impeller 18 with respect to the housing 11. .. A cylindrical bearing holding sleeve 33 made of iron is press-fitted to the inner peripheral surface of the through hole 12h. The second bearing 32 is arranged between the outer peripheral surface of the rotating shaft 17 and the inner peripheral surface of the bearing holding sleeve 33. The other end of the rotating shaft 17 is rotatably supported by the bottom wall 12 a of the motor housing 12 via the second bearing 32 and the bearing holding sleeve 33. Therefore, the rotating shaft 17 is rotatably supported by the housing 11 via the first bearing 31 and the second bearing 32.

The second bearing 32 includes a second inner ring 32a fixed to the outer peripheral surface of the rotating shaft 17, a second outer ring 32b arranged outside the second inner ring 32a, a second inner ring 32a and a second outer ring 32b. It is an angular contact ball bearing having a plurality of spherical second rolling elements 32c arranged therebetween. The second inner ring 32a is press fitted into the outer peripheral surface of the rotary shaft 17. The second outer ring 32b is fitted into the inner peripheral surface of the bearing holding sleeve 33 with a clearance.

In the through hole 12h, a housing chamber 34 is provided between the bearing holding sleeve 33 and the cover 15 in the axial direction of the rotary shaft 17. A washer 35 is provided inside the bearing holding sleeve 33 so as to come into contact with the end surface of the second outer ring 32b on the accommodation chamber 34 side. Further, a preload spring 36 is housed in the housing chamber 34. The preload spring 36 is interposed between the washer 35 and the cover 15.

One end of the preload spring 36 contacts the cover 15, and the other end of the preload spring 36 contacts the washer 35. The preload spring 36 is arranged between the cover 15 and the washer 35 while being compressed in the axial direction of the rotary shaft 17. Therefore, the cover 15 holds the preload spring 36. Then, the preload spring 36 urges the second bearing 32 through the washer 35 in the axial direction of the rotary shaft 17 by the force of returning to the original shape of the compressed preload spring 36.

The biasing force of the preload spring 36 is transmitted to the second outer ring 32b via the washer 35, and the biasing force transmitted to the second outer ring 32b is transmitted to the second inner ring 32a via the second rolling element 32c. As a result, the second inner ring 32a is pressed toward the impeller 18 in the axial direction of the rotating shaft 17. Then, the biasing force of the preload spring 36 is transmitted from the second inner ring 32a to the rotating shaft 17, and the rotating shaft 17 tends to move toward the impeller 18 in the axial direction of the rotating shaft 17. The rotary shaft 17 is in contact with the first inner ring 31a of the first bearing 31, and the first rolling element 31c is pressed against the rotary shaft 17 by the first inner ring 31a toward the impeller 18 in the axial direction, so that the first outer ring 31b is pressed. Then, the first outer ring 31b is pressed against the first rolling element 31c so as to be in contact with the engaging portion 40e.

In the electric supercharger 10, when the impeller 18 rotates, a thrust force is generated in the impeller 18 to pull the rotary shaft 17 in the axial direction of the rotary shaft 17 from the second bearing 32 toward the first bearing 31. The first bearing 31 and the second bearing 32 rotatably support the rotary shaft 17 while receiving a thrust force via the rotary shaft 17.

When the electric motor 19 is driven to rotate the rotating shaft 17, the impeller 18 rotates, and the centrifugal force of the rotating impeller 18 gives velocity energy to the air sucked from the suction port 13c. The air that has been supplied with velocity energy and has increased in velocity is decelerated in the diffuser flow path 13f provided at the outlet of the impeller 18, and the velocity energy of the air is converted into pressure energy. Then, the high-pressure air is discharged from the discharge chamber 13e and supplied to an engine (not shown).

As shown in FIG. 2, a circular hole-shaped recess 40c is formed in the end surface 40b of the seal plate 40 on the compressor housing 13 side. The inside of the recess 40c communicates with the bearing holding hole 40h.

The retainer 41 is fitted in the recess 40c. The retainer 41 is attached to the seal plate 40 by a bolt 42 penetrating the retainer 41 being screwed into the bottom surface of the recess 40c.

As shown in FIG. 4, the retainer 41 has an insertion hole 41h through which the rotary shaft 17 is inserted. The insertion hole 41h is formed in a portion of the plate 14 closer to the impeller chamber 13d than the bearing holding hole 40h. A cylindrical seal collar 43 made of iron is arranged inside the insertion hole 41h. The seal collar 43 is attached to the outer peripheral surface of the rotary shaft 17 in a state of being sandwiched between a step portion formed on the outer peripheral surface of the rotary shaft 17 and the back surface of the impeller 18. Therefore, the seal collar 43 rotates integrally with the rotating shaft 17.

An annular mounting groove 43a is formed on the outer peripheral surface of the seal collar 43. A metal seal ring 44 is mounted in the mounting groove 43a. The seal ring 44 has a non-annular shape with a notch formed in a part thereof. Then, the seal ring 44 is accommodated in the mounting groove 43a in a state of being reduced in diameter by the notch, and the seal ring 44 returns to its original shape in the mounting groove 43a, so that the outer peripheral surface of the seal ring 44 is inserted into the insertion hole. It is in contact with the inner peripheral surface of 41h. Thereby, the seal ring 44 seals between the mounting groove 43a and the insertion hole 41h.

The seal ring 44 is made of austenitic stainless steel. Therefore, the seal ring 44 is a non-magnetic material. The term “non-magnetic material” as used herein includes one in which the seal ring 44 is somewhat attracted toward the electric motor 19 due to the magnetic force generated by the magnetic field generated while the electric motor 19 is being driven. The thickness H1 of the seal ring 44 and the width H2 of the mounting groove 43a in the axial direction of the rotary shaft 17 are determined by the magnetic force from the electric motor 19 even if the seal ring 44 is slightly attracted toward the electric motor 19. The thickness and width are set so that the inner surface of the mounting groove 43a does not come into contact with the portion located on the electric motor 19 side.

A recess 41a is formed on the end surface of the retainer 41 on the bottom surface side of the recess 40c and around the insertion hole 41h. An annular flange 43f projects from an end of the outer peripheral surface of the seal collar 43 opposite to the impeller 18. The flange portion 43f is located inside the recess 41a of the retainer 41. The flange portion 43f cooperates with the seal ring 44 to function as a labyrinth seal.

As shown in FIG. 2, the seal plate 40 has a plate-shaped deflector portion 40g protruding inward in the radial direction of the rotary shaft 17 from a part of the inner peripheral surface of the engaging portion 40e. In addition, the seal plate 40 has a first oil drain that connects the motor chamber 20 with a portion located inside the engagement portion 40e and on the opposite side of the deflector portion 40g in the radial direction of the rotating shaft 17. A path 40k is formed. Further, as shown in FIG. 3, the bottom wall 12 a of the motor housing 12 is formed with a second oil discharge passage 12 k that connects the housing chamber 34 and the motor chamber 20.

As shown in FIG. 5, an oil supply passage 51 through which oil flows is formed in a part of the peripheral wall 12b of the motor housing 12. The oil supply flow path 51 is bored by, for example, a drill from the end surface of the peripheral wall 12b of the motor housing 12 on the opening 12c side. The oil supply passage 51 extends in the axial direction of the rotary shaft 17 from the end surface of the peripheral wall 12b of the motor housing 12 on the side of the opening 12c toward the bottom wall 12a. The opening on the end face side of the peripheral wall 12b of the motor housing 12 on the side of the opening 12c in the oil supply passage 51 is closed by the seal plate 40. The end portion of the oil supply passage 51 on the bottom wall 12a side of the motor housing 12 is located at a position overlapping the through hole 12h in the radial direction of the rotating shaft 17.

A first pipe mounting hole 12e and a second pipe mounting hole 12f are formed in the peripheral wall 12b of the motor housing 12. The first pipe mounting hole 12e and the second pipe mounting hole 12f are circular holes. One end of the first pipe mounting hole 12e is opened near the end on the seal plate 40 side in the oil supply passage 51. The other end of the first pipe mounting hole 12e is formed on the inner peripheral surface of the peripheral wall 12b of the motor housing 12 with respect to the space between the electric motor 19 and the first bearing 31 in the axial direction of the rotating shaft 17 of the rotating shaft 17. The openings are located at overlapping positions in the radial direction. One end of the second pipe mounting hole 12f is opened in the oil supply flow path 51 toward the bottom wall 12a side end of the motor housing 12. The other end of the second pipe mounting hole 12f is provided on the inner peripheral surface of the peripheral wall 12b of the motor housing 12 with respect to the space between the electric motor 19 and the second bearing 32 in the axial direction of the rotating shaft 17 of the rotating shaft 17. The openings are located at overlapping positions in the radial direction.

A first connecting hole 12m and a second connecting hole 12n are formed in the peripheral wall 12b of the motor housing 12. The first connecting hole 12m and the second connecting hole 12n are circular hole-shaped female screw holes. The first connection hole 12m is arranged in the peripheral wall 12b of the motor housing 12 at a position overlapping the first pipe mounting hole 12e in the radial direction of the rotating shaft 17. One end of the first connection hole 12m is open to the outer peripheral surface of the peripheral wall 12b of the motor housing 12. The other end of the first connection hole 12m opens into the oil supply passage 51. The first connection hole 12m extends in the radial direction of the rotary shaft 17. The diameter of the first connection hole 12m is larger than the diameter of the first pipe mounting hole 12e. The second connection hole 12n is arranged in the peripheral wall 12b of the motor housing 12 at a position overlapping the second pipe mounting hole 12f in the radial direction of the rotating shaft 17. One end of the second connection hole 12n opens to the outer peripheral surface of the peripheral wall 12b of the motor housing 12. The other end of the second connection hole 12n opens into the oil supply passage 51. The second connection hole 12n extends in the radial direction of the rotating shaft 17. The hole diameter of the second connection hole 12n is larger than the hole diameter of the second pipe mounting hole 12f.

The first oil supply pipe 55 is attached to the first pipe attachment hole 12e. The first oil supply pipe 55 extends linearly. The first oil supply pipe 55 is attached to the peripheral wall 12b of the motor housing 12 by passing through the first connection hole 12m and the oil supply flow path 51 and by press-fitting one end into the first pipe attachment hole 12e. .. The other end of the first oil supply pipe 55 passes through the first pipe mounting hole 12e and projects between the electric motor 19 and the first bearing 31 in the motor chamber 20 in the axial direction of the rotary shaft 17. There is. Therefore, the first oil supply pipe 55 is arranged between the electric motor 19 and the seal plate 40 in the axial direction of the rotary shaft 17. The first oil supply pipe 55 extends in the radial direction of the rotary shaft 17.

The first oil supply pipe 55 has a first supply passage 55a. The first supply passage 55 a communicates with the first in-shaft passage 551 a that extends in the axial direction of the first oil supply pipe 55 inside the first oil supply pipe 55 and the first in-shaft passage 551 a, and the first supply passage 55 a of the first bearing 31. It has the 1st ejection hole 552a which ejects oil toward between the 1st inner ring 31a and the 1st outer ring 31b. One end of the first in-shaft passage 551a communicates with the oil supply passage 51. Therefore, the first supply passage 55 a communicates with one end of the rotary shaft 17 in the oil supply passage 51 in the axial direction, and supplies the oil from the oil supply passage 51 to the first bearing 31. The first in-shaft passage 551a extends in the radial direction of the rotating shaft 17. The first ejection hole 552a extends in the axial direction of the rotary shaft 17. One end of the first ejection hole 552a communicates with the end of the first in-shaft passage 551a on the opposite side of the oil supply flow path 51. The other end of the first ejection hole 552a is open to the outer peripheral surface of the other end of the first oil supply pipe 55. The first ejection hole 552a faces a part between the first inner ring 31a and the first outer ring 31b in the axial direction of the rotating shaft 17. The flow passage cross-sectional area of the first ejection hole 552a is smaller than the flow passage cross-sectional area of the first in-shaft passage 551a.

The second oil supply pipe 56 is attached to the second pipe attachment hole 12f. The second oil supply pipe 56 extends linearly. The second oil supply pipe 56 is attached to the peripheral wall 12b of the motor housing 12 by passing through the second connection hole 12n and the oil supply flow path 51 and press-fitting one end into the second pipe attachment hole 12f. .. The other end of the second oil supply pipe 56 passes through the second pipe mounting hole 12f and projects between the electric motor 19 and the second bearing 32 in the motor chamber 20 in the axial direction of the rotating shaft 17. There is. Therefore, the second oil supply pipe 56 is arranged between the electric motor 19 and the bottom wall 12 a of the motor housing 12 in the axial direction of the rotary shaft 17. The second oil supply pipe 56 extends in the radial direction of the rotating shaft 17.

The second oil supply pipe 56 has a second supply passage 56a. The second supply passage 56 a communicates with the second in-shaft passage 561 a that extends in the axial direction of the second oil supply pipe 56 inside the second oil supply pipe 56, and communicates with the second in-shaft passage 561 a and the second bearing 32. It has the 2nd ejection hole 562a which ejects oil toward the 2nd inner ring 32a and the 2nd outer ring 32b. One end of the second in-shaft passage 561a communicates with the oil supply passage 51. Therefore, the second supply passage 56a communicates with the inner side of the oil supply passage 51 near the other end of the rotary shaft 17 in the axial direction, and supplies the oil from the oil supply passage 51 to the second bearing 32. The second in-shaft passage 561 a extends in the radial direction of the rotary shaft 17. The second ejection hole 562a extends in the axial direction of the rotary shaft 17. One end of the second ejection hole 562a communicates with the end of the second in-shaft passage 561a on the opposite side of the oil supply flow path 51. The other end of the second ejection hole 562a is open to the outer peripheral surface of the other end of the second oil supply pipe 56. The second ejection hole 562a faces a part between the second inner ring 32a and the second outer ring 32b in the axial direction of the rotating shaft 17. The flow passage cross-sectional area of the second ejection hole 562a is smaller than the flow passage cross-sectional area of the second in-shaft passage 561a.

The peripheral wall 12b of the motor housing 12 has a first oil supply hole 57a and a second oil supply hole 57b. One ends of the first oil supply hole 57a and the second oil supply hole 57b open in the oil supply passage 51, and in the axial direction of the rotating shaft 17, a first pipe mounting hole 12e and a second pipe mounting hole 12f are formed. It is located between. Therefore, the first oil supply hole 57a and the second oil supply hole 57b communicate with each other between the first supply passage 55a and the second supply passage 56a in the oil supply passage 51 in the axial direction of the rotating shaft 17.

The other end of the first oil supply hole 57a is opened on the inner peripheral surface of the peripheral wall 12b of the motor housing 12 at a position overlapping the first coil end 23a in the radial direction of the rotating shaft 17. Then, the first oil supply hole 57a supplies the oil flowing through the oil supply passage 51 to the first coil end 23a. The other end of the second oil supply hole 57b is opened on the inner peripheral surface of the peripheral wall 12b of the motor housing 12 at a position overlapping the second coil end 23b in the radial direction of the rotating shaft 17. Then, the second oil supply hole 57b supplies the oil flowing through the oil supply passage 51 to the second coil end 23b.

An oil introduction pipe 58 is attached to the first connection hole 12m. In the oil introduction pipe 58, a part of the oil stored in the oil pan of the engine flows. Then, the oil flowing through the oil introduction pipe 58 is supplied into the oil supply passage 51. Therefore, the oil introduction pipe 58 is an oil supply unit that communicates with the first supply passage 55a in the oil supply passage 51 and supplies oil to the oil supply passage 51.

A closing member 59 is attached to the second connection hole 12n. The closing member 59 is attached to the second connection hole 12n after being attached to the second pipe attachment hole 12f in the second oil supply pipe 56.

On the inner surface of the peripheral wall 12b of the motor housing 12 forming the oil supply passage 51, the first surface 511 located closer to the rotary shaft 17 has an end located closer to the oil introducing pipe 58 than the end located closer to the closing member 59. It is an inclined surface that is inclined so as to gradually approach the rotary shaft 17 as it goes toward the portion. The first surface 511 is flat. On the inner surface of the peripheral wall 12b of the motor housing 12 forming the oil supply flow path 51, the second surface 512 located on the opposite side to the rotating shaft 17 extends from the end located near the oil introduction pipe 58 to the closing member 59. It has an inclined surface that gradually inclines so as to gradually separate from the rotary shaft 17 toward the end portion located closer to it. The second surface 512 has a flat surface shape. The second surface 512 is a surface that faces the first surface 511 in the radial direction of the rotating shaft 17. Therefore, the oil supply flow passage 51 has a flow passage cross-sectional area that gradually increases from the oil introduction pipe 58 toward the second supply passage 56a.

As shown in FIG. 1, a discharge passage 20k for discharging the oil in the motor chamber 20 to the outside of the housing 11 is formed in a portion of the peripheral wall 12b of the motor housing 12 opposite to the oil supply passage 51. There is. In the electric supercharger 10 of the present embodiment, the oil supply flow path 51 is located above the rotation shaft 17 in the gravity direction, and the discharge passage 20k and the second oil discharge passage 12k are arranged in the gravity direction relative to the rotation shaft 17. It is installed in the engine room so that it is located on the lower side. As shown in FIG. 2, in the seal plate 40, the deflector portion 40g is located closer to the oil supply passage 51 in the radial direction of the rotary shaft 17, and the first oil drain passage 40k is in the radial direction of the rotary shaft 17. It is attached to the motor housing 12 so as to be located near the discharge passage 20k. Therefore, the deflector portion 40g is located above the rotating shaft 17 in the direction of gravity, and the first oil discharge passage 40k is located below the rotating shaft 17 in the direction of gravity.

As shown in FIG. 5, the oil supplied to the oil supply passage 51 from the oil introduction pipe 58 and filled in the oil supply passage 51 is the first supply passage 55 a of the first oil supply pipe 55 and the second oil supply. Each flows into the second supply path 56a of the pipe 56. The oil flowing into the first supply passage 55a and the second supply passage 56a respectively passes through the first in-shaft passage 551a and the second in-shaft passage 561a.

The oil that has passed through the first in-shaft passage 551a is ejected from the first ejection hole 552a toward between the first inner ring 31a and the first outer ring 31b. At this time, since the flow passage cross-sectional area of the first ejection hole 552a is smaller than the flow passage cross-sectional area of the first axial passage 551a, the oil is squeezed when passing through the first ejection hole 552a and the first inner ring. It is ejected vigorously from the first ejection hole 552a toward the space between 31a and the first outer ring 31b. As a result, oil is efficiently supplied between the first inner ring 31a and the first outer ring 31b, slidability between the first outer ring 31b and each first rolling element 31c, and the first inner ring 31a and each first rolling element 31c. The slidability between the first rolling element 31c is improved.

The oil that has passed between the first inner ring 31a and the first outer ring 31b collides with the deflector portion 40g, and the deflector portion 40g guides the oil flow toward the first oil discharge passage 40k. It flows from the inside toward the first oil discharge passage 40k. Then, the oil passes through the first oil discharge passage 40k, flows into the motor chamber 20, is discharged to the outside of the housing 11 through the discharge passage 20k, and is returned to the oil pan of the engine.

The oil that has passed through the second in-shaft passage 561a is ejected from the second ejection hole 562a toward the space between the second inner ring 32a and the second outer ring 32b. At this time, since the flow passage cross-sectional area of the second ejection hole 562a is smaller than the flow passage cross-sectional area of the second in-shaft passage 561a, the oil is squeezed when passing through the second ejection hole 562a and the second inner ring. It is vigorously ejected from the second ejection hole 562a toward the space between 32a and the second outer ring 32b. As a result, oil is efficiently supplied between the second inner ring 32a and the second outer ring 32b, slidability between the second outer ring 32b and each second rolling element 32c, and the second inner ring 32a and each first rolling element 32c. The slidability between the two rolling elements 32c is improved.

The oil that has passed between the second inner ring 32a and the second outer ring 32b flows into the storage chamber 34. Then, the oil passes through the second oil discharge passage 12k, flows into the motor chamber 20, is discharged to the outside of the housing 11 through the discharge passage 20k, and is returned to the oil pan of the engine.

Further, the oil filled in the oil supply passage 51 passes through the first oil supply hole 57a and is supplied to the first coil end 23a. Further, the oil with which the oil supply flow path 51 is filled passes through the second oil supply hole 57b and is supplied to the second coil end 23b. As a result, the first coil end 23a and the second coil end 23b are cooled, and as a result, the electric motor 19 is cooled. Therefore, the oil supply passage 51 is formed in the housing 11, and the oil supplied to the first bearing 31, the second bearing 32, and the electric motor 19 flows. The oil that has contributed to the cooling of the first coil end 23a and the second coil end 23b is discharged to the outside of the housing 11 through the discharge passage 20k and is returned to the oil pan of the engine.

Next, the operation of this embodiment will be described.
Since the seal ring 44 is a non-magnetic body formed of austenitic stainless steel, for example, compared with the case where the seal ring 44 is a magnetic body, the magnetic force generated by the magnetic field generated during driving of the electric motor 19 causes It is suppressed that the seal ring 44 is drawn toward the electric motor 19. Therefore, in the state where the inner surface of the mounting groove 43a and the seal ring 44 are in contact with each other, the seal collar 43 rotates integrally with the rotating shaft 17, and the seal ring 44 is worn, so that the mounting groove 43a and the seal ring 44 are worn. The problem that the gap between and becomes larger than the expected gap is avoided. As a result, the oil supplied to the first bearing 31 is suppressed from passing through the gap between the mounting groove 43a and the seal ring 44 from the bearing holding hole 40h, and the oil supplied to the first bearing 31 is impeller. Leakage into the chamber 13d is suppressed.

In addition, the oil supply passage 51 has a passage cross-sectional area that gradually increases from the oil introduction pipe 58 that communicates with the first supply passage 55a in the oil supply passage 51 toward the second supply passage 56a. Therefore, the oil supplied from the oil introduction pipe 58 to the oil supply passage 51 easily flows toward the second supply passage 56a. Therefore, the amount of oil supplied from the oil supply passage 51 to the second supply passage 56a arranged at a position farther from the oil introduction pipe 58 than the first supply passage 55a is equal to the oil supply passage to the first supply passage 55a. It is equivalent to the oil supply amount from 51. As a result, it becomes easier to uniformly supply the oil to the first bearing 31 and the second bearing 32. Further, the amount of oil supplied from the oil supply passage 51 to the second oil supply hole 57b arranged at a position farther from the oil introduction pipe 58 than the first oil supply hole 57a is to the first oil supply hole 57a. It is equal to the amount of oil supplied from the oil supply passage 51. As a result, it becomes easier to uniformly supply the oil to the first coil end 23a and the second coil end 23b.

In the above embodiment, the following effects can be obtained.
(1) The seal ring 44 is a non-magnetic material. According to this, compared with the case where the seal ring 44 is a magnetic body, for example, the seal ring 44 is attracted toward the electric motor 19 by the magnetic force associated with the magnetic field generated during driving of the electric motor 19. Can be suppressed. Therefore, in the state where the inner surface of the mounting groove 43a and the seal ring 44 are in contact with each other, the seal collar 43 rotates integrally with the rotating shaft 17, and the seal ring 44 is worn, so that the mounting groove 43a and the seal ring 44 are worn. It is possible to avoid the problem that the gap between and becomes larger than the expected gap. As a result, the oil supplied to the first bearing 31 is suppressed from passing through the gap between the mounting groove 43a and the seal ring 44 from the bearing holding hole 40h, so the oil supplied to the first bearing 31 is suppressed. Can be suppressed from leaking into the impeller chamber 13d.

(2) The seal ring 44 is made of austenitic stainless steel. Austenitic stainless steel is a particularly suitable material for making the seal ring 44 a non-magnetic material.

(3) The oil supply passage 51 has a passage cross-sectional area that gradually increases from the oil introduction pipe 58 toward the second supply passage 56a. According to this, the oil supplied from the oil introduction pipe 58 to the oil supply passage 51 easily flows toward the second supply passage 56a. Therefore, the oil supply amount from the oil supply passage 51 to the second supply passage 56a arranged at a position farther from the oil introduction pipe 58 than the first supply passage 55a is calculated as follows. The oil supply amount from 51 can be made equal. As a result, the oil is easily evenly supplied to the first bearing 31 and the second bearing 32, so that the slidability of the first bearing 31 and the second bearing 32 can be improved.

(4) The amount of oil supplied from the oil supply passage 51 to the second oil supply hole 57b arranged at a position farther from the oil introduction pipe 58 than the first oil supply hole 57a is to the first oil supply hole 57a. It is equal to the amount of oil supplied from the oil supply passage 51. Therefore, the oil is easily supplied uniformly to the first coil end 23a and the second coil end 23b, and the temperature of the entire stator 21 can be made uniform.

(5) The first connection hole 12m is arranged in the peripheral wall 12b of the motor housing 12 at a position overlapping the first pipe mounting hole 12e in the radial direction of the rotating shaft 17. The second connection hole 12n is arranged in the peripheral wall 12b of the motor housing 12 at a position overlapping the second pipe mounting hole 12f in the radial direction of the rotating shaft 17. According to this, processing of the peripheral wall 12b in the first pipe mounting hole 12e in which the first oil supply pipe 55 is mounted and processing of the peripheral wall in the first connection hole 12m in which the oil introduction pipe 58 is mounted are performed in one step. You can Further, the processing of the peripheral wall in the second pipe mounting hole 12f in which the second oil supply pipe 56 is mounted and the processing of the peripheral wall 12b in the second connection hole 12n in which the closing member 59 is mounted can be performed in one step. Therefore, the electric supercharger 10 can be easily manufactured.

The above-described embodiment can be modified and implemented as follows. The above-described embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.

In the embodiment, the seal ring 44 may be made of a material other than austenitic stainless steel as long as it is a non-magnetic material. For example, the seal ring 44 may be made of resin.

In the embodiment, on the inner surface forming the oil supply passage 51, the first surface 511 located near the rotating shaft 17 is located at the end located near the oil introducing pipe 58 and the end located near the closing member 59. The curved surface may be curved so as to gradually approach the rotating shaft 17 as it goes. Further, in the inner surface forming the oil supply flow path 51, the second surface 512 located on the side opposite to the rotating shaft 17 is located from the end located near the oil introduction pipe 58 to the end located near the blocking member 59. The curved surface may be curved so as to gradually separate from the rotating shaft 17 as it goes.

In the embodiment, the electric supercharger 10 may have a configuration in which the oil introduction pipe 58 is attached to the second connection hole 12n and the closing member 59 is attached to the first connection hole 12m. In this case, it is preferable that the oil supply flow passage 51 has a flow passage cross-sectional area gradually increasing from the oil introduction pipe 58 toward the first supply passage 55a. In short, in the electric supercharger 10, the oil supply unit that supplies oil to the oil supply passage 51 communicates with one side of the first supply passage 55a and the second supply passage 56a in the oil supply passage 51, It suffices that the oil supply flow passage 51 has a configuration in which the flow passage cross-sectional area gradually increases from the oil supply portion toward the other of the first supply passage 55a and the second supply passage 56a.

In the embodiment, the first connection hole 12m may not be formed in the peripheral wall 12b of the motor housing 12 at a position where it does not overlap the first pipe mounting hole 12e in the radial direction of the rotating shaft 17, and It suffices if it is formed near the pipe mounting hole 12e. In short, the oil introduction pipe 58 attached to the first connection hole 12m communicates with the first oil supply pipe 55 attached to the first pipe attachment hole 12e near the first supply passage 55a in the oil supply passage 51. It should be.

In the embodiment, for example, one of the first oil supply hole 57a and the second oil supply hole 57b may not be formed in the peripheral wall 12b of the motor housing 12.
In the embodiment, the first oil supply hole 57a and the second oil supply hole 57b may not be formed in the peripheral wall 12b of the motor housing 12.

In the embodiment, the electric supercharger 10 may not have the first oil supply pipe 55. In this case, the first supply passage for supplying the oil from the oil supply passage 51 to the first bearing 31 may be formed in the plate 14, for example.

In the embodiment, the electric supercharger 10 may not have the second oil supply pipe 56. In this case, the second supply passage for supplying the oil from the oil supply passage 51 to the second bearing 32 may be formed in the bottom wall 12a of the motor housing 12, for example.

In the embodiment, the bearing is not limited to the ball bearing, and for example, a cylindrical plain bearing may be used.
Next, the technical ideas that can be understood from the above-described embodiment and other examples will be added below.

(A) A housing having a tubular peripheral wall, a rotary shaft rotatably supported by the housing, an electric motor housed in the housing and rotating the rotary shaft, and an axial direction of the rotary shaft. An impeller connected to an end portion, a first bearing that rotatably supports a portion of the rotary shaft between the electric motor and the impeller with respect to the housing, and a first bearing that is more than the electric motor of the rotary shaft. A second bearing that rotatably supports the portion opposite to the impeller with respect to the housing; an oil supply passage that is formed in the peripheral wall and extends in the axial direction of the rotating shaft and through which oil flows; A first supply passage that communicates with one end of the rotary shaft in the supply passage in the axial direction, and that supplies oil from the oil supply passage to the first bearing; and the rotation in the oil supply passage. A second supply path communicating with the other end of the shaft in the axial direction and supplying the oil from the oil supply path to the second bearing; the first supply path and the first supply path in the oil supply path; An electric supercharger comprising: an oil supply portion that communicates with one of the two supply passages and supplies oil to the oil supply passage, wherein the oil supply passage extends from the oil supply portion to the first supply passage. The electric supercharger, wherein the flow passage cross-sectional area gradually increases toward the other of the first supply passage and the second supply passage.

According to this, the oil supply passage is directed from the oil supply portion that communicates with one side of the first supply passage and the second supply passage in the oil supply passage to the other of the first supply passage and the second supply passage. Since the flow passage cross-sectional area gradually increases as a result, the oil supplied from the oil supply portion to the oil supply flow passage easily flows toward the other of the first supply passage and the second supply passage. Therefore, the amount of oil supplied from the oil supply passage to the other of the first supply passage and the second supply passage arranged at a position farther from the oil supply portion than one of the first supply passage and the second supply passage, The amount of oil supplied from the oil supply passage to one of the first supply passage and the second supply passage can be made equal. As a result, the oil is easily supplied evenly to the first bearing and the second bearing, so that the slidability of the first bearing and the second bearing can be improved.

(B) The electric motor has a tubular stator around which a coil is wound, and the stator is a stator core and both ends of the stator core that are located in the axial direction of the rotary shaft of the stator core. A first coil end and a second coil end that respectively project from the surface, and flows through the oil supply flow path at a position on the peripheral wall that overlaps the first coil end in the radial direction of the rotation shaft. A first oil supply hole for supplying oil to the first coil end is formed, and the oil supply passage is formed at a position on the peripheral wall that overlaps the second coil end in the radial direction of the rotating shaft. A second oil supply hole for supplying flowing oil to the second coil end is formed, and the first oil supply hole and the second oil supply hole are formed in the oil supply passage in the axial direction of the rotating shaft. The electric supercharger according to the above-mentioned technical idea (a), characterized in that the electric supercharger is communicated between the first supply path and the second supply path.

According to this, the oil supply flow path for the other of the first oil supply hole and the second oil supply hole, which is arranged at a position farther from the oil supply unit than one of the first oil supply hole and the second oil supply hole. Can be made equal to the oil supply amount from the oil supply passage to one of the first oil supply hole and the second oil supply hole. As a result, it becomes easier to uniformly supply the oil to the first coil end and the second coil end, so that the temperature of the entire stator can be made uniform.

DESCRIPTION OF SYMBOLS 10... Electric supercharger, 11... Housing, 13d... Impeller chamber, 14... Plate which functions as a bearing holding wall, 17... Rotating shaft, 18... Impeller, 19... Electric motor, 20... Motor chamber, 31... As bearing 1st bearing, 40h... Bearing holding hole, 41h... Insertion hole, 43... Seal collar, 43a... Mounting groove, 44... Seal ring.

Claims (2)

Housing,
A rotation shaft rotatably supported by the housing,
An electric motor housed in the housing and rotating the rotating shaft;
An impeller connected to the axial end of the rotating shaft,
A motor chamber formed in the housing and accommodating the electric motor;
An impeller chamber formed in the housing and accommodating the impeller,
A bearing holding hole that is disposed between the motor chamber and the impeller chamber and holds a bearing that rotatably supports a portion of the rotating shaft between the electric motor and the impeller with respect to the housing. Bearing retaining wall,
An insertion hole formed in a portion of the bearing holding wall closer to the impeller chamber than the bearing holding hole, and through which the rotating shaft is inserted,
A tubular seal collar that is arranged inside the insertion hole and rotates integrally with the rotary shaft,
An electric supercharger comprising: a seal ring that is mounted in an annular mounting groove formed on the outer peripheral surface of the seal collar and seals between the mounting groove and the insertion hole;
The electric supercharger, wherein the seal ring is a non-magnetic material. The electric supercharger according to claim 1, wherein the seal ring is made of austenitic stainless steel.