Electric supercharger

Abstract

An electric supercharger (1) is provided with a motor (20), a stator case (23) that is thermally connected with respect to a stator (22), a motor housing (25) that houses the stator case (23), and a diffuser plate (40) that is thermally connected with respect to the stator (22). The stator case (23) and the motor housing (25) cooperate to form a first flow path (F1) that is disposed on the first end surface (22a) side in a manner surrounding the rotational axis (RL). The diffuser plate (40) has a second flow path (F2) that is disposed on the second end surface (22b) side in a manner surrounding the rotational axis (RL) and is separated from the first flow path (F1) in the direction of the rotational axis (RL).

Description

Technical Field

[0001] This disclosure relates to electric superchargers. Background Technology

[0002] An electric supercharger uses a motor to rotate a compressor impeller. The compressor impeller compresses air. The compressed air becomes hot. The motor that rotates the compressor impeller is a heat source. The temperature of the components constituting the electric supercharger rises due to the heat of the compressed air and the motor. This temperature rise can cause the electric supercharger to fail to perform as desired. Patent Document 1 discloses a cooling structure for cooling the motor and turbine. Patent Document 2 discloses a cooling structure for cooling the back of the compressor impeller.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2010-196478

[0004] Patent Document 2: Japanese Patent Application Publication No. 2017-150339

[0005] There is a desire to further improve the performance of the electric supercharger. Improving the performance of the electric supercharger requires increasing the motor's output. The motor increases its output by being supplied with a large current. If a large current is supplied to the motor, it becomes under high load, thus generating more heat. If the motor's temperature rises due to heat, the motor's magnets will demagnetize. Due to magnet demagnetization, the motor's output may decrease. Therefore, it is necessary to further improve the motor's cooling performance. Summary of the Invention

[0006] This disclosure describes an electric supercharger that can further improve cooling performance.

[0007] As one aspect of this disclosure, an electric supercharger includes: a motor having a stator disposed on a circumference based on a rotation axis; a first component thermally connected to a first end face of the stator in the direction of the rotation axis; a second component thermally connected to a second end face of the stator in the direction of the rotation axis; and a third component connected to the first component. The first and third components cooperate to form a first flow path disposed on the first end face side in a manner surrounding the rotation axis. The second component has a second flow path disposed on the second end face side in a manner surrounding the rotation axis and separated from the first flow path in the direction of the rotation axis.

[0008] The electric supercharger disclosed herein can further improve cooling performance. Attached Figure Description

[0009] Figure 1 This is a cross-sectional view that schematically represents the structure of the electric supercharger of this disclosure.

[0010] Figure 2This is an exploded perspective view showing an example of an electric supercharger.

[0011] Figure 3 Observing from another direction Figure 2 An exploded 3D diagram.

[0012] Figure 4 This is an exploded perspective view showing an example of an electric supercharger.

[0013] Figure 5 Observing from another direction Figure 4 An exploded 3D diagram.

[0014] Figure 6 It is a cross-sectional view that roughly shows the relationship between the diffuser plate and the passage block.

[0015] Figure 7 This is a diagram that roughly represents an example of a flow path. Detailed Implementation

[0016] As one aspect of this disclosure, an electric supercharger includes: a motor having a stator disposed on a circumference based on a rotation axis; a first component thermally connected to a first end face of the stator in the direction of the rotation axis; a second component thermally connected to a second end face of the stator in the direction of the rotation axis; and a third component connected to the first component. The first and third components cooperate to form a first flow path disposed on the first end face side in a manner surrounding the rotation axis. The second component has a second flow path disposed on the second end face side in a manner surrounding the rotation axis and separated from the first flow path in the direction of the rotation axis.

[0017] A current is supplied to the stator of the electric supercharger to generate a rotating magnetic field. The stator heats up due to the supplied current. A first component is thermally connected to a first end face of the stator. The first and third components cooperate to form a first flow path. The electric supercharger can extract heat from the first end face of the stator by supplying a heat transfer medium to the first flow path. A second component is thermally connected to a second end face of the stator. The second component has a second flow path. The electric supercharger can extract heat from the second end face of the stator by supplying a heat transfer medium to the second flow path. Therefore, the electric supercharger can extract more heat from the stator. As a result, the cooling performance of the electric supercharger can be further improved.

[0018] The second component can also be a diffuser plate. The first component can also be a stator housing that holds the stator. The third component can also be a motor housing that houses the stator housing.

[0019] The stator housing may also have: a housing body housing the stator, and housing ribs extending from the outer peripheral surface of the housing body. The electric turbocharger may also include a passage block disposed between the housing ribs separated by the housing body and the diffuser plate. The passage block may also have a connecting passage connecting the first flow path and the second flow path. The connecting passage of the passage block connects the first flow path and the second flow path. As a result, for the electric turbocharger, the flow path cooling both the first and second end faces of the stator can be combined into a single flow path. Therefore, for the electric turbocharger, the structure for providing heat medium to the flow path can be simplified, and the structure for discharging heat medium from the flow path can be simplified.

[0020] The passage block can also have an inlet flow path that guides the heat medium from the outside to the second flow path. The connecting flow path can also guide the heat medium from the second flow path to the first flow path. With this structure, for the electric booster, it is possible to simplify the structure for providing the heat medium to the flow path and the structure for discharging the heat medium from the flow path.

[0021] The second projected area of ​​the second flow path as observed from the axis of rotation can be different from the first projected area of ​​the first flow path as observed from the axis of rotation. With this structure, the electric booster can adjust the balance between the heat removed from the stator through the first flow path and the heat removed from the stator through the second flow path.

[0022] The second projected area of ​​the second flow path as viewed from the axis of rotation can be larger than the first projected area of ​​the first flow path as viewed from the axis of rotation. According to this structure, for the electric supercharger, it is possible to remove more heat from the stator through the second flow path than through the first flow path.

[0023] The first flow path may include: an inner flow path portion that surrounds the rotation axis; an outer flow path portion that surrounds the rotation axis and is offset relative to the inner flow path portion in the direction of the rotation axis; and an intermediate flow path portion that is disposed between the inner and outer flow path portions and extends obliquely relative to the direction of the rotation axis. According to this structure, the electric booster can effectively remove heat from the first end face of the stator.

[0024] The first flow path includes: a flow path main body comprising an inner flow path portion, a middle flow path portion, and an outer flow path portion; a first auxiliary flow path portion extending from one end of the flow path main body portion in a direction intersecting the rotation axis; and a second auxiliary flow path portion extending from the other end of the flow path main body portion in a direction intersecting the rotation axis. The width along the circumference of the rotation axis from one end of the flow path main body portion to the other end of the flow path main body portion can be smaller than the width from the first auxiliary flow path portion to the second auxiliary flow path portion. According to this structure, the electric booster can further and better remove heat from the first end face of the stator.

[0025] The electric supercharger of this disclosure will now be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are labeled with the same reference numerals, and repeated descriptions are omitted.

[0026] Figure 1 This is a cross-sectional view that schematically illustrates the structure of the electric supercharger 1 of this disclosure. (See attached image.) Figure 1 As shown, the electric supercharger 1 includes a compressor 10, a motor 20, and a rotating shaft 30. The electric supercharger 1 drives the compressor 10 using the motor 20, which is powered by electricity. The electric supercharger 1 discharges compressed air. The electric supercharger 1 rotates the compressor 10 by utilizing a turbine to recover energy from the discharged gas. The electric supercharger 1 assists in rotational torque by mounting the motor 20 on the rotating shaft 30.

[0027] The compressor 10 receives power from the motor 20 via a rotating shaft 30. The compressor 10 draws in air through an impeller 11 rotating around the rotating shaft 30. The compressor 10 compresses the drawn-in air. The compressed air is discharged through a vortex flow path 12 located inside the compressor 10.

[0028] Motor 20 drives compressor 10. Motor 20 has rotor 21, stator 22, stator housing 23 (first component), passage block 24 and motor housing 25 (third component).

[0029] Rotor 21 is fixed to rotating shaft 30. Rotor 21 is generally cylindrical in shape. Rotor 21 surrounds rotating shaft 30. Rotor 21 and rotating shaft 30 rotate together. Rotor 21 includes, for example, multiple permanent magnets.

[0030] The stator 22 surrounds the outer peripheral surface of the rotor 21. The stator 22 is generally cylindrical in shape. Teeth are formed on the inner peripheral surface of the stator 22. A coil is wound on the teeth. The coil faces the outer peripheral surface of the rotor 21. Current is supplied to the coil of the stator 22. When current is supplied to the coil, the rotor 21 rotates. The stator 22 has a first end face 22a and a second end face 22b. The first end face 22a faces the bottom surface of the stator housing 23. The second end face 22b faces the diffuser plate 40 (second component). The coil end, which is the end of the coil, is exposed on the first end face 22a. The coil end, which is the end of the coil, is also exposed on the second end face 22b. The coil end is arranged, for example, in an annular shape near the outer peripheral surface of the first end face 22a. The coil end is also arranged, for example, in an annular shape near the outer peripheral surface of the second end face 22b.

[0031] The stator housing 23 holds the stator 22. The stator housing 23 has a housing body 23s and a housing rib 23d. The housing body 23s is generally cylindrical. The stator 22 is fixed inside the housing body 23s. A housing opening 23a is formed at one end of the housing body 23s. The housing opening 23a is closed by a diffuser plate 40. The other end of the housing body 23s is closed by a housing end face 23b. The peripheral wall 23c of the housing body 23s surrounds the outer peripheral surface of the stator 22. A plate-shaped housing rib 23d is provided at the end of the peripheral wall 23c on the side of the housing end face 23b. The housing rib 23d is continuous with the housing end face 23b. The housing rib 23d extends outward from the housing body 23s. The housing rib 23d is disposed between the passage block 24 (described later) and the motor housing 25. The housing rib 23d is in contact with the passage block 24. The housing rib 23d is also in contact with the motor housing 25.

[0032] The stator housing 23 is thermally connected to the first end face 22a of the stator 22. Thermal connection means that the thermal conductivity between the stator housing 23 and the first end face 22a is higher than the thermal conductivity of air. As an example, a state where the stator housing 23 and the first end face 22a are in physical contact can be cited. As another example, a state where the gap between the stator housing 23 and the first end face 22a is filled with a heat-transferring material such as heat-transferring grease can be cited.

[0033] The passage block 24 is block-shaped. It is separate from the stator housing 23. The passage block 24 has a main surface 24a and a back surface 24b. The main surface 24a is in contact with the housing rib 23d. The back surface 24b is in contact with the diffuser plate 40. For example, two through holes are formed in the passage block 24. These through holes extend from the main surface 24a to the back surface 24b. The passage block 24 is disposed between the housing rib 23d and the diffuser plate 40 of the stator housing 23. The passage block 24 has at least one curved surface with a curvature consistent with the peripheral wall 23c. This curved surface is in contact with the peripheral wall 23c. The passage block 24 is disposed between the stator housing 23 and the diffuser plate 40. The passage block 24 is located on the side of the stator housing 23. The two through holes formed in the passage block 24 are closed by the housing rib 23d and the diffuser plate 40.

[0034] The motor housing 25 houses the stator housing 23 and the passage block 24. The motor housing 25 is connected to the stator housing 23. The motor housing 25 has a generally circular container shape. The motor housing 25 has a wall surface 25a. The wall surface 25a faces the housing end face 23b of the stator housing 23. The wall surface 25a is connected to the housing end face 23b.

[0035] A first flow path F1 for a heat transfer medium is formed in the motor housing 25. In one example, a slot and a hole for the first flow path F1 are formed in the motor housing 25. The motor housing 25 is watertightly connected to the stator housing 23 in a manner that seals the first flow path F1. The motor housing 25 and the stator housing 23 cooperate to form the first flow path F1. The first flow path F1 allows the flow of a heat transfer medium such as cooling water. As a result, the first end face 22a of the stator 22 is cooled.

[0036] The diffuser plate 40 is a circular plate-shaped component. The diffuser plate 40 has a motor-side main surface 40a and a compressor-side back surface 40b. The motor-side main surface 40a faces the housing opening 23a of the stator housing 23. The motor-side main surface 40a closes the housing opening 23a. The motor-side main surface 40a is in contact with the passage block 24. The compressor-side back surface 40b faces the compressor 10. The compressor-side back surface 40b forms a flow path for compressed air.

[0037] The diffuser plate 40 is a circular plate-shaped component. The diffuser plate 40 is composed of two circular plates. The two circular plates constituting the diffuser plate 40 are made of different materials. In one example, the diffuser plate 40 has a first circular plate component 40S and a second circular plate component 40K. The first circular plate component 40S includes a motor-side main surface 40a. The second circular plate component 40K includes a compressor-side back surface 40b. The thermal conductivity of the material constituting the first circular plate component 40S is different from the thermal conductivity of the material constituting the second circular plate component 40K. The thermal conductivity of the first circular plate component 40S is higher than that of the second circular plate component 40K. Because the two circular plates are made of materials with different thermal conductivity, a deviation can be made in the thermal movement from the motor 20 to the motor-side main surface 40a and from the compressor 10 to the compressor-side back surface 40b. The diffuser plate 40 can promote thermal movement from the motor 20 side to the motor-side main surface 40a, which has higher thermal conductivity. That is, the diffuser plate 40 can promote thermal movement from the stator 22 constituting the motor 20. The diffuser plate 40 can suppress thermal movement from the compressor 10 side to the compressor side back surface 40b with low thermal conductivity.

[0038] The diffuser plate 40 is thermally connected to the second end face 22b of the stator 22. In one example, the diffuser plate 40 is in contact with the second end face 22b. In another example, the diffuser plate 40 may be separated from the second end face 22b. A heat transfer material such as heat transfer lubricant is filled between the diffuser plate 40 and the second end face 22b.

[0039] A second flow path F2 for a heat transfer medium is formed in the diffuser plate 40. Holes and slots constituting the second flow path F2 are formed in at least one of a first circular plate member 40S including the motor-side main surface 40a and a second circular plate member 40K including the compressor-side back surface 40b. The first circular plate member 40S is watertightly connected to the second circular plate member 40K in a manner that seals the second flow path F2. The second flow path F2 is formed inside the diffuser plate 40. A heat transfer medium, such as cooling water, flows through the second flow path F2. As a result, the second end face 22b of the stator 22 is cooled.

[0040] The passage block 24 connects the first flow path F1 to the second flow path F2. In one example, the heating medium is supplied through the passage block 24 via the through hole 24H1 (see reference). Figure 6 The heat medium flows from the first flow path F1 to the second flow path F2. Additionally, the heating medium supplied by the passage block 24 flows from the second flow path F2 to the first flow path F1 via the through hole 24H1. The motor housing 25 has a supply port and a discharge port for the heat medium.

[0041] Figure 2 This is a perspective view showing an example of the electric supercharger 1 exploded. A first annular portion 23b1, a second annular portion 23b2, a third annular portion 23b3, a through hole 23H1, and a through hole 23H2 are formed on the end face 23b of the housing. Packing material P1 and packing material P2 are disposed on the end face 23b of the housing.

[0042] The first annular portion 23b1 includes a generally annular surface and a surface shaped along the end face of the housing rib 23d. The second annular portion 23b2 is located within the inner circumference of the first annular portion 23b1. The second annular portion 23b2 is an annular edge. The second annular portion 23b2 protrudes towards the motor housing 25 with the first annular portion 23b1 as its base end. The third annular portion 23b3 is located within the inner circumference of the second annular portion 23b2. The third annular portion 23b3 is continuously formed from the end of the second annular portion 23b2 in the direction towards the motor housing 25, forming a surface parallel to the first annular portion 23b1. The first annular portion 23b1, the second annular portion 23b2, and the third annular portion 23b3 each surround the rotation axis RL.

[0043] Through hole 23H1 is a hole that extends from one end face of shell rib 23d to the other end face. Through hole 23H2 is also a hole that extends from one end face of shell rib 23d to the other end face. Through hole 23H1 is one of the outlet for hot medium flowing out of passage block 24 and the inlet for hot medium flowing into passage block 24. Through hole 23H2 is the other of the outlet for hot medium flowing out of passage block 24 and the inlet for hot medium flowing into passage block 24.

[0044] Packing P1 and packing P2 are sealing components made of rubber or the like. Packing P1 is arranged along the outer periphery of the first annular portion 23b1. Packing P2 is arranged along the inner periphery of the third annular portion 23b3.

[0045] Figure 3 It will be different from Figure 2 This is an exploded perspective view of an example of an electric supercharger 1 as observed from the direction of rotation. A flow path groove 25G, a packing groove PG1, and a packing groove PG2 are formed on the wall surface 25a of the motor housing 25. The flow path groove 25G forms a first flow path F1. The flow path groove 25G includes an inlet / outlet portion 25G1, an annular groove portion 25G2, a connecting groove portion 25G3, and a pocket portion 25G4. The flow path groove 25G is formed in an annular shape surrounding the rotation axis RL. Alternatively, when viewed from above in the direction of the rotation axis RL, the flow path groove 25G may be located at a position closer to the outer periphery than the coil end. The coil end is exposed from the first end face 22a of the stator 22. The flow path groove 25G may also overlap with the coil end.

[0046] The inlet / outlet portion 25G1 is the end of the flow channel 25G. The flow channel 25G is formed, for example, by two recesses. The inlet / outlet portion 25G1 is connected to a through hole 23H1 formed on the end face 23b of the housing. The inlet / outlet portion 25G1 is also connected to a through hole 23H2 formed on the end face 23b of the housing.

[0047] The annular groove 25G2 is an annular groove. The annular groove 25G2 surrounds the axis of rotation RL with a central angle of 180 degrees or more. The annular groove 25G2 is located on the inner circumference of the packing groove PG1. The annular groove 25G2 is located on the outer circumference of the packing groove PG2.

[0048] The connecting groove 25G3 connects the inlet / outlet section 25G1 to the annular groove 25G2. If the inlet / outlet section 25G1 is formed on the annular groove 25G2 without separating from it, the connecting groove 25G3 can be omitted.

[0049] The pocket portion 25G4 consists of two recesses continuously formed with the annular groove portion 25G2. The two pocket portions 25G4 are formed opposite each other. The distance from one pocket portion 25G4 to the other pocket portion 25G4 is shorter than the interval connecting the two inlet and outlet portions 25G1. The interval through which the hot medium flows through the pocket portions 25G4 is narrower than the interval between the inlet flowing into the passage block 24 and the outlet flowing out of the passage block 24.

[0050] The packing groove PG1 corresponds to the packing P1 on the end face 23b of the stator housing 23. The packing groove PG2 corresponds to the packing P2. The flow path groove 25G is located between the packing grooves PG1 and PG2. When the motor housing 25 and the stator housing 23 are in contact, the packing P1 is fixed to the packing groove PG1. When the motor housing 25 and the stator housing 23 are in contact, the packing P2 is fixed to the packing groove PG2. As a result, the motor housing 25 and the stator housing 23 can watertightly retain the flow path groove 25G.

[0051] Figure 4 This is a perspective view showing an example of an electric supercharger 1 disassembled. Figure 4 This indicates that the motor housing 25 is connected to the stator housing 23. A packing material P3 is provided on the housing rib 23d. The packing material P3 is positioned between the housing rib 23d and the passage block 24.

[0052] Figure 5 From different Figure 4 The exploded view shows a perspective view of an example of the electric supercharger 1. The passage block 24 includes a through hole 24H1, a through hole 24H2, and a packing groove 24PG3. The through hole 24H1 forms a connecting flow path F3a. The through hole 24H2 forms an inlet flow path F3b.

[0053] Through hole 24H1 extends from the main face 24a of the block to the back face 24b of the block. Through hole 24H2 also extends from the main face 24a to the back face 24b of the block. Through hole 24H1 is one of the outlet for the hot medium flowing out of the passage block 24 and the inlet for the hot medium flowing into the passage block 24. Through hole 24H2 is the other of the outlet for the hot medium flowing out of the passage block 24 and the inlet for the hot medium flowing into the passage block 24. Through hole 23H1 is formed in the shell rib 23d of the stator housing 23. Through hole 23H1 is connected to the through hole 24H1 on the main face 24a side of the block. Through hole 23H2 is formed in the shell rib 23d of the stator housing 23. Through hole 23H2 is connected to the through hole 24H2 on the main face 24a side of the block. The through holes 24H1 and 24H2 on the back side 24b of the block are respectively connected to the inflow and outlet portions 40G1 (described later) formed on the diffuser plate 40.

[0054] The packing groove PG3 corresponds to the packing P3. Packing P3 is positioned between the housing rib 23d and the passage block 24. The packing groove PG3 is located on the outer periphery of the through hole 24H1. The packing groove PG3 is also located on the outer periphery of the through hole 24H2. When the housing rib 23d and the passage block 24 are in contact, the packing P3 is fixed to the packing groove PG3. By fixing the packing P3, the housing rib 23d and the passage block 24 can watertightly maintain the through hole 24H1. The housing rib 23d and the passage block 24 can also watertightly maintain the through hole 24H2.

[0055] A through hole 40H is formed in the diffuser plate 40. The through hole 40H extends from the main surface 40a on the motor side to the rear surface 40b on the compressor side. The center of the through hole 40H is aligned with the axis of rotation RL.

[0056] Figure 6 This is a cross-sectional view that schematically shows the relationship between the diffuser plate 40 and the passage block 24. As described above, the diffuser plate 40 is configured as a single circular plate component by bonding two circular plates together. The two circular plates refer to the first circular plate component 40S, which includes the motor-side main surface 40a, and the second circular plate component 40K, which includes the compressor-side back surface 40b. The following description addresses the case where the first circular plate component 40S has a groove and a hole formed for the second flow path F2.

[0057] A flow path groove 40G is provided on the diffuser plate 40. The flow path groove 40G forms a second flow path F2. The flow path groove 40G includes an inlet / outlet portion 40G1, an annular groove portion 40G2, a connecting groove portion 40G3, and a pocket portion 40G4. The flow path groove 40G is formed in an annular shape surrounding the rotation axis RL. Alternatively, when viewed from above along the rotation axis RL, the flow path groove 40G may be located at a position closer to the outer periphery than the coil end. The coil end is exposed from the second end face 22b of the stator 22. The flow path groove 40G may also overlap with the coil end.

[0058] The compressor side face 40b includes an impeller region 40b1 and a diffuser region 40b2. The impeller region 40b1 faces the impeller 11 of the compressor 10. The diffuser region 40b2 and the compressor 10 together form the flow path for compressed air. The diffuser region 40b2 surrounds the impeller region 40b1.

[0059] The inlet / outlet portion 40G1 is the end of the flow channel 40G. The inlet / outlet portion 40G1 is formed, for example, by two recesses. Through holes 24H1 and 24H2 are formed on the back side 24b of the block.

[0060] The annular groove 40G2 is an annular groove. The annular groove 40G2 surrounds the axis of rotation RL with a central angle of more than 180 degrees.

[0061] The connecting groove 40G3 connects the inlet / outlet section 40G1 to the annular groove 40G2. If the inlet / outlet section 40G1 is formed on the annular groove 40G2 without separating from it, the connecting groove 40G3 can be omitted.

[0062] The pocket portion 40G4 consists of two recesses continuously formed with the annular groove portion 40G2. The pocket portions 40G4 are formed opposite each other with a gap narrower than the gap connecting the two inlet and outlet portions 40G1. The gap in the pocket portions 40G4 that allows the hot medium to flow is narrower than the gap between the inlet that flows in from the passage block 24 and the outlet that flows out of the passage block 24.

[0063] Figure 7 This is a diagram that roughly represents an example of a flow path. (See reference...) Figure 7 In (a), the motor housing 25, stator housing 23, passage block 24 and diffuser plate 40 are respectively watertightly connected. Figure 7 (b) roughly represents a first flow path F1, a second flow path F2, a connecting flow path F3a, and an inlet flow path F3b forming a connected flow path.

[0064] Figure 7 (b) represents an example of a first flow path F1, a second flow path F2, a connecting flow path F3a, and an inlet flow path F3b. The first flow path F1 extends from the first end face 22a of the stator 22 along at least a portion of the side surface of the stator 22. The first flow path F1 extends toward the second end face 22b of the stator 22. The first flow path F1 has a flow path main body F1s, a first auxiliary flow path F1r1, and a second auxiliary flow path F1r2. The width along the rotation axis RL, from one end of the flow path main body F1s to the other end of the flow path main body F1s, is smaller than the width from the first auxiliary flow path F1r1 to the second auxiliary flow path F1r2. This is because a pocket portion 25G4 (see reference) is provided in the flow path main body F1s. Figure 6 ).

[0065] The main body of the flow path F1s includes an outer flow path F1a, a middle flow path F1b, and an inner flow path F1c. A first auxiliary flow path F1r1 is connected to one end of the main body of the flow path F1s. A second auxiliary flow path F1r2 is connected to the other end of the main body of the flow path F1s.

[0066] The outer flow path F1a surrounds the rotation axis RL. The outer flow path F1a is offset relative to the inner flow path F1c in the direction of the rotation axis RL. The distance from the outer flow path F1a to the compressor 10 is shorter than the distance from the inner flow path F1c to the compressor 10. The outer flow path F1a is formed by a flow path groove 25G and a first annular portion 23b1. The flow path groove 25G is formed on the wall surface 25a. The first annular portion 23b1 is formed on the housing end face 23b.

[0067] An intermediate flow path F1b is disposed between the inner flow path F1c and the outer flow path F1a. The intermediate flow path F1b connects the inner flow path F1c and the outer flow path F1a. Therefore, the intermediate flow path F1b extends obliquely relative to the rotation axis RL. The intermediate flow path F1b is formed by a flow path groove 25G and a second annular portion 23b2.

[0068] The inner flow path F1c surrounds the rotation axis RL. The inner flow path F1c is formed by the flow path groove 25G and the third annular portion 23b3. The intermediate flow path F1b and the inner flow path F1c extend from the first end face 22a of the stator 22 along at least a portion of the side surface of the stator 22. The intermediate flow path F1b and the inner flow path F1c extend toward the second end face 22b of the stator 22.

[0069] The hot medium flows into the first flow path F1 from the supply port FS. The incoming hot medium flows in the order of the inlet flow path F3b, the second flow path F2, and the connecting flow path F3a. The hot medium is discharged from the outlet FV. The supply port FS and the outlet FV are located on the motor housing 25.

[0070] The first flow path F1 and the second flow path F2 enclose the rotation axis RL. The first flow path F1 and the second flow path F2 are annular. The projected area of ​​the first flow path F1 as viewed from the rotation axis RL is different from the projected area of ​​the second flow path F2. When viewed from the rotation axis RL, the outer diameter of the second flow path F2 is larger than the outer diameter of the first flow path F1. Alternatively, when viewed from the rotation axis RL, the inner diameter of the second flow path F2 is smaller than the inner diameter of the first flow path F1. The surface area of ​​the second flow path F2 on the surface opposite the second end face 22b of the stator 22 is different from the surface area of ​​the first flow path F1 on the surface opposite the first end face 22a of the stator 22. The surface area of ​​the second flow path F2 can also be larger than the surface area of ​​the first flow path F1.

[0071] The electric booster 1 includes: a motor 20 having a stator 22 disposed on a circumference with respect to a rotation axis RL; a stator housing 23 (first component) holding the stator 22 and thermally connected to a first end face 22a of the stator 22 in the direction of the rotation axis RL of the motor 20; a diffuser plate 40 (second component) thermally connected to a second end face 22b of the stator 22 in the direction of the rotation axis RL; and a motor housing 25 (third component) connected to the stator housing 23. The stator housing 23 and the motor housing 25 cooperate to form a first flow path F1 disposed on the side of the first end face 22a in a manner surrounding the rotation axis RL. The diffuser plate 40 has a second flow path F2 disposed on the side of the second end face 22b in a manner surrounding the rotation axis RL and separated from the first flow path F1 in the direction of the rotation axis RL.

[0072] A current for generating a rotating magnetic field is supplied to the stator 22 of the electric supercharger 1. The stator 22 heats up due to the supplied current. The stator housing 23 is thermally connected to the first end face 22a of the stator 22. The stator housing 23 (first component) and the motor housing 25 (third component) cooperate to form a first flow path F1. The electric supercharger 1 can extract heat from the first end face 22a of the stator 22 by supplying a heat transfer medium to the first flow path F1. The diffuser plate 40 (second component) is thermally connected to the second end face 22b of the stator 22. The diffuser plate 40 has a second flow path F2. The electric supercharger 1 can extract heat from the second end face 22b of the stator 22 by supplying a heat transfer medium to the second flow path F2. Therefore, the electric supercharger 1 can extract more heat from the stator 22. As a result, the cooling performance of the electric supercharger 1 can be further improved.

[0073] The main heat source of the motor 20 is the stator 22, which contains the coils. Current is supplied to the coils of the motor 20 as a power source. Heat is generated due to resistance as the current flows through the coils. If the temperature of the motor 20 rises due to heating, demagnetization occurs in the magnets constituting the motor 20. As a result, the output of the motor 20 may decrease. Therefore, cooling of the motor 20 is necessary. The electric booster 1 includes a cooling mechanism comprising a first flow path F1 and a second flow path F2. The cooling mechanism uses both end faces of the stator 22 as heat paths. The cooling mechanism efficiently dissipates heat, particularly from the coil ends exposed from the first end face 22a and the second end face 22b of the stator 22.

[0074] The electric booster 1 includes: a motor 20 having a stator 22, a motor housing 25 thermally connected to a first end face 22a of the stator 22, and a diffuser plate 40 thermally connected to a second end face 22b of the stator 22. A first flow path F1 for a heat medium is formed in the motor housing 25. A second flow path F2 for a heat medium is formed in the diffuser plate 40.

[0075] Coil ends, serving as the ends of coils, are exposed at the end faces on both sides of the stator 22. In the electric booster 1, the motor housing 25, which forms the first flow path F1, is thermally connected to the first end face 22a of the stator 22. The diffuser plate 40, which forms the second flow path F2, is thermally connected to the second end face 22b of the stator 22. With this structure, the electric booster 1 allows the heat medium to flow in both the first flow path F1 and the second flow path F2. As a result, the electric booster 1 can efficiently dissipate heat from the end faces on both sides of the stator 22. Therefore, the electric booster 1 can further improve cooling performance.

[0076] The stator housing 23 has a housing body 23s that houses the stator 22, and a housing rib 23d extending from the outer peripheral surface of the housing body 23s. The electric booster 1 also includes a passage block 24 disposed between the housing rib 23d separated by the housing body 23s and the diffuser plate 40. The passage block 24 has a connecting flow path F3a that connects the first flow path F1 and the second flow path F2. According to this structure, the first flow path F1 is connected to the second flow path F2 via the connecting flow path F3a of the passage block 24. As a result, the electric booster 1 can make the flow paths for cooling both the first end face 22a and the second end face 22b of the stator 22 a single flow path. Therefore, the electric booster 1 simplifies the structure for providing heat to the flow path and the structure for discharging heat from the flow path.

[0077] The electric turbocharger 1 may also include a stator housing 23 and a passage block 24. The stator housing 23 holds the stator 22. The passage block 24 is disposed between the stator housing 23 and the diffuser plate 40, and is disposed on the side of the stator housing 23. With this structure, the electric turbocharger 1 can also obtain good cooling performance. The first flow path F1 and the second flow path F2 are connected to form a connected flow path. Since the supply port FS and the discharge port FV of the heat medium can be formed as one, the electric turbocharger 1 has a simple structure. The passage block 24 is a separate component from the stator housing 23. As a result, the stator housing 23 can be easily manufactured. Compared with the case where the passage block 24 and the stator housing 23 are manufactured as the same component, the thermal deformation of the stator housing 23 can be made uniform during hot pressing. As a result, the electric turbocharger 1 can suppress the reduction in yield due to poor hot pressing.

[0078] The passage block 24 also has an inlet flow path F3b that guides the heat medium from the outside to the second flow path F2. The connecting flow path F3a guides the heat medium from the second flow path F2 to the first flow path F1. With this structure, the electric booster 1 can also simplify the structure for supplying heat medium to the flow path and the structure for discharging heat medium from the flow path.

[0079] The second projected area of ​​the second flow path F2, as observed from the rotation axis RL, is different from the first projected area of ​​the first flow path F1, as observed from the rotation axis RL. According to this structure, the electric booster 1 can adjust the balance between the heat taken from the stator 22 through the first flow path F1 and the heat taken from the stator 22 through the second flow path F2.

[0080] The surface area of ​​the second flow path F2 on the surface opposite the second end face 22b of the stator 22 is different from the surface area of ​​the first flow path F1 on the surface opposite the first end face 22a of the stator 22. Even with this structure, the electric supercharger 1 can achieve good cooling performance.

[0081] The second projected area of ​​the second flow path F2, as observed from the rotation axis RL, is greater than the first projected area of ​​the first flow path F1, as observed from the rotation axis RL. According to this structure, the electric booster 1 can absorb more heat from the stator 22 through the second flow path F2 than it absorbs through the first flow path F1.

[0082] The surface area of ​​the second flow path F2 is larger than that of the first flow path F1. The diffuser plate 40, on the surface opposite to the surface thermally connected to the second end face 22b of the stator 22, receives heat from the air compressed by the compressor impeller. In the electric booster 1, by increasing the surface area of ​​the flow path of the diffuser plate 40, heat can be efficiently extracted from the coil ends. The electric booster 1 can suppress heat transfer from compressed air to the second end face 22b of the stator 22. Therefore, the electric booster 1 can further improve cooling performance.

[0083] The first flow path F1 includes: an inner flow path F1c that surrounds the rotation axis RL; an outer flow path F1a that surrounds the rotation axis RL and is offset relative to the inner flow path F1c in the direction of the rotation axis RL; and an intermediate flow path F1b disposed between the inner flow path F1c and the outer flow path F1a, and extending obliquely relative to the direction of the rotation axis RL. According to this structure, the electric booster 1 can effectively remove heat from the first end face 22a of the stator 22.

[0084] The first flow path F1 is configured to extend from the first end face 22a of the stator 22 along at least a portion of the side surface of the stator 22 toward the second end face 22b of the stator 22. With this structure, the first flow path F1 is formed on the side of the first end face 22a of the stator 22. As a result, the electric booster 1 can allow the heat transfer medium to flow to a portion closer to the coil end. Therefore, the electric booster 1 can further improve cooling performance.

[0085] The first flow path F1 includes: a flow path main body F1s, which includes an inner flow path F1c, a middle flow path F1b, and an outer flow path F1a; a first auxiliary flow path F1r1, which extends from one end of the flow path main body F1s in a direction intersecting the rotation axis RL; and a second auxiliary flow path F1r2, which extends from the other end of the flow path main body F1s in a direction intersecting the rotation axis RL. The width along the rotation axis RL from one end of the flow path main body F1s to the other end of the flow path main body F1s is smaller than the width from the first auxiliary flow path F1r1 to the second auxiliary flow path F1r2. According to this structure, the electric booster 1 can further and better extract heat from the first end face 22a of the stator 22.

[0086] A pocket 25F4 is formed in the diffuser plate 40, which allows the heat medium to flow through at a distance narrower than the gap between the inlet and outlet of the passage block 24. If the flow paths on both sides of the stator 22 are connected, the heat medium may not flow through the flow path of the diffuser plate 40 by the amount between the inlet and outlet of the passage block 24. In the electric supercharger 1, the flow path of the diffuser plate 40 is widened by the pocket 25F4. Therefore, the electric supercharger 1 can further improve the cooling performance.

[0087] The motor housing 25 has a supply port FS and an outlet FV for the heat medium in the second flow path F2. This structure also allows the electric turbocharger 1 to achieve good cooling performance. The motor housing 25 has a sufficient volume compared to the diffuser plate 40. Therefore, the electric turbocharger 1 can be easily configured with the supply port FS and outlet FV for the heat medium in the second flow path F2.

[0088] The electric booster 1 disclosed herein is not limited to the structure of the embodiments described above. In the embodiments, the motor housing 25 and the stator housing 23 cooperate to form a first flow path F1. For example, a groove and a hole forming the first flow path F1 may be formed in either the motor housing 25 or the stator housing 23.

[0089] Furthermore, in the above embodiment, the stator housing 23 is shown as the first component that connects to the first end face 22a of the stator 22. The motor housing 25 is shown as the third component that connects to the stator housing 23. Specific examples of the first, second, and third components are not limited to those shown above. For example, the first component that connects to the first end face 22a of the stator 22 could also be the motor housing. The third component that connects to the motor housing could also be the stator housing.

[0090] Explanation of reference numerals in the attached figures:

[0091] 1…Electric booster; 10…Compressor; 20…Motor; 21…Rotor; 22…Stator; 22a…First end face; 22b…Second end face; 23…Stator housing (first component); 23s…Housing body; 23d…Housing rib; 24…Passage block; 25…Motor housing (third component); 25G…Flow channel; 25G1…Inlet / outlet section; 25G2…Annular groove; 25G3…Connecting groove; 25G4…Pocket section; 30…Rotating shaft; 40…Expansion Dispenser plate (second component); 40G1…Inlet / outlet section; 40G2…Annular groove section; 40G3…Connecting groove section; 40G4…Pocket section; F1…First flow path; F1a…Outer flow path section; F1b…Middle flow path section; F1c…Inner flow path section; F1r1…First auxiliary flow path section; F1r2…Second auxiliary flow path section; F2…Second flow path; F3a…Connecting flow path; F3b…Inlet flow path; FS…Supply port; FV…Discharge port; RL…Rotation axis.

Claims

1. An electric booster, characterized in that, have: A motor having a stator arranged on a circumference with respect to a rotation axis; A first component is thermally connected relative to a first end face of the stator in the direction of the rotation axis; The second component is thermally connected relative to the second end face of the stator in the direction of the rotation axis; as well as The third component is connected to the first component. The first component and the third component cooperate to form a first flow path disposed on the first end face side in a manner that surrounds the axis of rotation. The second component has a second flow path disposed on the second end face side in a manner surrounding the rotation axis, and separated from the first flow path in the direction of the rotation axis. The first component is the stator housing that holds the stator. The second component is a diffuser plate. The stator housing has: a housing body that houses the stator, and housing ribs extending from the outer peripheral surface of the housing body. The electric supercharger also includes a passage block disposed between the housing rib separated by the housing body and the diffuser plate. The pathway block has a connecting pathway that connects the first flow path and the second flow path to each other.

2. The electric booster according to claim 1, characterized in that, The third component is the motor housing that houses the stator housing.

3. The electric booster according to claim 1, characterized in that, The passage block also has an inlet flow path that guides the heat medium from the outside to the second flow path. The connecting flow path guides the heat medium from the second flow path to the first flow path.

4. The electric supercharger according to any one of claims 1 to 3, characterized in that, The second projected area of ​​the second flow path as observed from the axis of rotation is different from the first projected area of ​​the first flow path as observed from the axis of rotation.

5. The electric booster according to any one of claims 1 to 3, characterized in that, The second projected area of ​​the second flow path as observed from the axis of rotation is greater than the first projected area of ​​the first flow path as observed from the axis of rotation.

6. The electric booster according to any one of claims 1 to 3, characterized in that, The first flow path includes: The inner flow path surrounds the axis of rotation; An outer flow path portion that surrounds the rotation axis and is offset relative to the inner flow path portion in the direction of the rotation axis; and An intermediate flow path is disposed between the inner flow path and the outer flow path, and extends obliquely relative to the direction of the rotation axis.

7. The electric booster according to claim 6, characterized in that, The first flow path has: The main body of the flow path includes the inner flow path, the middle flow path, and the outer flow path; A first auxiliary flow path portion extends from one end of the flow path main body portion in a direction intersecting the rotation axis; as well as The second auxiliary flow path section extends from the other end of the flow path main body section in a direction intersecting the axis of rotation. The width along the axis of rotation, from one end of the main body of the flow path to the other end of the main body of the flow path, is smaller than the width from the first auxiliary flow path to the second auxiliary flow path.

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