Rotating electric machine

Abstract

The present invention provides a rotating electric machine capable of stably maintaining rotational force.　A rotating electric machine 1 includes: a coil 41 disposed on a housing 10 side; and a permanent magnet 32 and a magnetic body 31 disposed on a shaft 20 side, the shaft being provided so as to be rotatable relative to the housing 10. A cooling flow path 60 having an inlet 60a and an outlet 60b is provided on one side of the shaft 20 in the axial direction. The cooling flow path 60 has a shaft flow path 62 that extends axially through at least a part of the shaft 20, and a magnetic body flow path 64 that passes axially through at least a part of the magnetic body 31.

Description

Rotating electric machines

[0001] The present invention relates to a rotating electric machine, for example, a rotating electric machine that can be cooled by a fluid.

[0002] Rotating electric machines that convert electromagnetic energy into mechanical energy or mechanical energy into electromagnetic energy by utilizing current flowing through coils are used in various industrial fields. Some of these rotating electric machines are equipped with a cooling structure to protect the permanent magnets from heat.

[0003] For example, the rotating electric machine disclosed in Patent Document 1 includes a hollow shaft and a rotor provided with permanent magnets. The hollow shaft has a hole extending in the axial direction. A liquid inlet pipe is inserted into the hollow shaft through the opening of the hole. The rotor is fitted and fixed to the outside of the hollow shaft. Coolant is supplied from the liquid inlet pipe toward the closed end of the hole, turns back at the closed end, and is discharged from a radial gap between the hollow shaft and the liquid inlet pipe. This allows the hollow shaft to be cooled.

[0004] Japanese Patent Application Laid-Open No. 7-170694 (page 2, Figure 1)

[0005] In the rotating electric machine of Patent Document 1, the rotor can be cooled via the cooled hollow shaft. However, because the permanent magnets provided in the rotor are located farther away from the hollow shaft, they cannot be cooled efficiently, which may result in a loss of torque.

[0006] The present invention has been made in view of the above-mentioned problems, and has as its object to provide a rotating electric machine that can stably maintain a rotational force.

[0007] In order to solve the above problems, the present invention provides a rotating electric machine including a coil installed on a housing side, and a permanent magnet and a magnetic body installed on a shaft that is rotatable relative to the housing, the rotating electric machine having a cooling flow path with an inlet and an outlet on one axial side of the shaft, the cooling flow path including a shaft flow path that extends axially through at least a portion of the shaft, and a magnetic body flow path that axially communicates with at least a portion of the magnetic body. In this way, the fluid flows in opposite axial directions in the shaft flow path and the magnetic body flow path, thereby cooling not only the shaft and its vicinity, but also the magnetic body and thereby the permanent magnet, thereby maintaining stable rotational efficiency of the rotating electric machine.

[0008] The magnetic material flow path may be provided closer to the permanent magnet than the shaft, thereby enabling more efficient cooling of the permanent magnet.

[0009] The permanent magnet may have a radial cross section having a long side and a short side, and the long side may be disposed opposite the magnetic material flow path, thereby enabling more efficient cooling of the permanent magnet.

[0010] The magnetic material flow path may be provided across at least the magnetic material, which allows the entire portion that functions as a magnet to be cooled, resulting in higher efficiency.

[0011] The magnetic flow path may be formed of a pipe. This allows for a simple configuration of a flow path that prevents the fluid passing through it from leaking to the outside. Also, the type of fluid used for cooling can be changed as needed.

[0012] The magnetic body may be formed by stacking a plurality of electromagnetic steel plates in the axial direction, thereby reducing heat generated by eddy currents.

[0013] The shaft may be a rotary shaft that rotates relative to the housing, the housing having an inlet pipe inserted into the rotary shaft and communicating with the inlet, a radial gap between the inlet pipe and the rotary shaft being an outlet flow passage communicating with the outlet, the outlet flow passage having a diameter larger than that of the shaft flow passage and including an expanded diameter portion through which the shaft flow passage and the magnetic material flow passage communicate with each other. In this way, the stepped shape formed by the expanded diameter portion and the shaft flow passage can make it difficult for fluid to flow from the outlet flow passage into the shaft flow passage.

[0014] The outlet flow passage may have a larger diameter than the shaft flow passage, which makes it easier to guide the fluid that has passed through the cooling flow passage and been heated out of the shaft.

[0015] The shaft flow passage may extend along the axial direction of the magnetic body, thereby enabling the shaft side of the magnetic body to be efficiently cooled along the axial direction.

[0016] The housing may be provided with a coil cooling passage surrounding the coil, which allows the coil side of the magnetic body to be cooled as well.

[0017] The space inside the housing where the magnetic body is disposed and the space communicating with the outlet may be sealed with a seal, which prevents fluid from adhering to the magnetic body or the coil, allowing the type of fluid used for cooling to be changed as needed.

[0018] Fig. 1 is a cross-sectional view of a rotating electric machine according to a first embodiment of the present invention. Fig. 2 is a cross-sectional view taken along the line A-A in Fig. 1. Fig. 3 is an enlarged view of a portion of the rotating electric machine according to the first embodiment. Fig. 4 is a view for explaining a magnetic material flow path of another aspect. Fig. 5 is a cross-sectional view of a rotating electric machine according to a second embodiment of the present invention. Fig. 6 is a perspective view for explaining a magnetic material flow path of a rotating electric machine according to a third embodiment of the present invention. Fig. 7 is a cross-sectional view of a rotating electric machine according to a fourth embodiment of the present invention.

[0019] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A rotating electric machine according to an embodiment of the present invention will be described below with reference to the accompanying drawings.

[0020] A rotating electric machine according to a first embodiment will be described with reference to Fig. 1 to Fig. 4. In the following description, the left and right sides of Fig. 1 will be referred to as the left and right sides of the rotating electric machine. Unless otherwise specified, the axial direction will be the axial direction of the rotating shaft, and the radial direction will be the radial direction of the rotating shaft.

[0021] 1, a rotating electric machine 1 of the present invention is connected to a water pump 2 through a supply pipe and a recovery pipe, and is capable of cooling a rotor 30 and a stator 40 with the cooling water delivered from the water pump 2. Note that the cooling fluid in this embodiment is primarily water, but is not limited to this and may be insulating oil, a refrigerant, or any other suitable fluid.

[0022] The rotating electric machine 1 includes a housing 10 , a rotating shaft 20 as a shaft, a rotor 30 , and a stator 40 .

[0023] The housing 10 defines a cylindrical space. The housing 10 is also provided with a cooling flow path 60 to which a first supply pipe S1 and a first recovery pipe R1 are connected, and a stator cooling flow path 70 as a coil cooling flow path to which a second supply pipe S2 and a second recovery pipe R2 are connected.

[0024] The first supply pipe S1 and the second supply pipe S2 are connected to a main supply pipe S outside the rotating electric machine 1. The main supply pipe S is connected to a water pump 2 and is a pipe for supplying the cooling water delivered from the water pump 2 to the rotating electric machine 1.

[0025] The first recovery pipe R1 and the second recovery pipe R2 are connected to the main recovery pipe R outside the rotating electric machine 1. The main recovery pipe R is connected to the water pump 2 through the radiator 3, and is a pipe for returning the cooling water that has passed through the rotating electric machine 1 to the water pump 2.

[0026] Although the cooling device in this embodiment is the radiator 3, it may be a refrigeration cycle or may be modified as appropriate. Furthermore, the fluid circuit connecting the rotating electrical machine 1, the water pump 2, and the radiator 3 is not limited to piping, but may be formed, for example, by holes formed directly in the housing, or may be modified as appropriate.

[0027] Referring to Figure 1, the housing 10 comprises, from the left in the axial direction, a cylindrical lid material 11 with a bottom, a cylindrical tubular material 12, a stepped cylindrical tubular material 13, an annular plate material 14, and a lid material 15 with a through hole.

[0028] A through-hole penetrating in the axial direction is formed in the cover material 11. The left end of the rotating shaft 20 is inserted into this through-hole. A seal ring and a bearing are provided radially between the cover material 11 and the rotating shaft 20, in this order from the left in the axial direction.

[0029] The cylindrical member 12 is formed in a cylindrical shape extending in the axial direction and is axially connected to the lid member 11. An O-ring seals the axial space between the cylindrical member 12 and the lid member 11. A stator 40 having a coil 41 is fitted and fixed inside the cylindrical member 12.

[0030] More specifically, the cylindrical material 12 has a cylindrical inner member 17 and a cylindrical outer member 18 fitted and fixed to the outside of the inner member 17, which together form a stator cooling passage 70 as described below, a so-called water jacket.

[0031] A spiral groove 17a extending in the circumferential direction and inclined axially to the right is formed on the outer peripheral surface of the inner member 17. The groove 17a is recessed from the outer peripheral surface of the inner member 17 toward the inner diameter side and opens toward the outer diameter side.

[0032] The outer member 18 is formed so that its inner peripheral surface conforms to the outer peripheral surface of the inner member 17. The outer member 18 is fitted and fixed to the outside of the inner member 17 to close the opening of the groove 17a and, together with the inner member 17, constitutes a part of the stator cooling flow passage 70.

[0033] Two through holes 18a, 18b that penetrate radially are formed in the outer member 18. The two through holes 18a, 18b are spaced apart from each other in the axial direction and form part of a stator cooling flow path 70.

[0034] More specifically, the left through-hole 18a is formed radially outward of the left axial end of the stator 40 and communicates with the left side of the groove 17a, while the right through-hole 18b is formed radially outward of the right axial end of the stator 40 and communicates with the right side of the groove 17a.

[0035] A second supply pipe S2 is connected to the left through-hole 18a, and a second recovery pipe R2 is connected to the right through-hole 18b.

[0036] The cooling water that flows into the stator cooling flow passage 70 from the second supply pipe S2 flows along the stator cooling flow passage 70 toward the right in the axial direction while swirling outward around the stator 40, and is collected into the water pump 2 through the second recovery pipe R2. This allows the cooling water passing through the stator cooling flow passage 70 to cool almost the entire circumference of the stator 40 in the axial direction.

[0037] The cylindrical material 13 has a cylindrical peripheral wall 13a extending in the axial direction, an annular connecting portion 13b extending from the right end of the peripheral wall 13a toward the inner diameter side, and a stepped cylindrical stepped portion 13c connected to the connecting portion 13b.

[0038] The peripheral wall 13a is axially connected to the cylindrical member 12. The axial gap between the peripheral wall 13a and the cylindrical member 12 is sealed by an O-ring.

[0039] The stepped portion 13c is formed in a stepped cylindrical shape whose diameter increases toward the right in the axial direction. A through-hole is formed in the stepped portion 13c, penetrating it in the axial direction. The right end of the rotating shaft 20 is inserted into this through-hole. A bearing is disposed between the stepped portion 13c and the rotating shaft 20.

[0040] Furthermore, a rotating element 51 of mechanical seal 50 is disposed on the right side of the through hole in stepped portion 13c. Rotating element 51 has a sleeve fitted over and fixed to the right end of rotating shaft 20, a rotary seal ring fixed to the sleeve, and a cup gasket as a secondary seal disposed between the rotary seal ring and the sleeve. Rotating element 51 rotates integrally with rotating shaft 20 with axial movement of the rotary seal ring restricted.

[0041] The plate member 14 is axially connected to the right end of the stepped portion 13c of the cylindrical member 13. The axial gap between the plate member 14 and the stepped portion 13c is sealed by an O-ring.

[0042] Furthermore, a through hole 14a extending in the axial direction is formed in the plate material 14. An inlet pipe 16 is inserted through this through hole 14a.

[0043] Furthermore, a communication hole 14b extending from the outer circumferential surface toward the inner diameter side and communicating with the through-hole 14a is formed in the plate material 14. A first recovery pipe R1 is connected to the communication hole 14b.

[0044] Furthermore, a stationary element 52 of the mechanical seal 50 is provided in the axial left portion of the through hole 14a in the plate material 14. The stationary element 52 has a case that is fitted and fixed to the plate material 14, a stationary seal ring that is held so as to be non-rotatable relative to the case but movable in the axial direction, an O-ring that serves as a secondary seal and is disposed between the stationary seal ring and the case, and a spring that is disposed axially between the stationary seal ring and the case.

[0045] The stationary seal ring of the mechanical seal 50 is pressed toward the rotary seal ring by a spring. This allows the sliding surfaces of the stationary seal ring and the rotary seal ring to slide relative to each other. In other words, the mechanical seal 50 is a stationary type. However, the mechanical seal 50 may be a rotary type, and the configurations of the rotating and stationary elements may be modified as appropriate.

[0046] The mechanical seal 50 seals the space within the housing 10 between an internal space sp1, in which the rotor 30 and the stator 40 are disposed, and an external space sp2, which communicates with the first recovery pipe R1. The space sp1 is partitioned mainly by the cover member 11, the cylindrical members 12 and 13, the plate member 14, and the mechanical seal 50. The space sp2 is partitioned mainly by the mechanical seal 50, the plate member 14, and the cover member 15, and communicates with the first recovery pipe R1 through the communication hole 14b.

[0047] A through hole extending in the axial direction is formed in the lid member 15. A female thread is formed in the axial left portion of the through hole in the lid member 15, and a male thread formed on the right end of the inlet pipe 16 is screwed and fixed to the female thread. A first supply pipe S1 is connected to the through hole. Note that the method of fixing the lid member 15 and the inlet pipe 16 is not limited to screwing and may be welding or may be changed as appropriate.

[0048] The inflow pipe 16 is formed into a cylindrical shape extending in the axial direction from a material with low thermal conductivity, and the cooling water introduced from the first supply pipe S1 flows into the through hole of the inflow pipe 16. In other words, the inflow pipe 16 constitutes an inflow flow path 61, which is a part of the cooling flow path 60. The material of the inflow pipe 16 may be changed as appropriate.

[0049] Here, the cooling flow path 60 includes an inflow flow path 61, a rotation axis flow path 62 as a shaft flow path, a branch flow path 63, a rotor flow path 64 as a magnetic material flow path, a radial flow path 65, and an outflow flow path 66. The flow paths other than the inflow flow path 61 will be described later.

[0050] The opening on the right side in the axial direction of the inlet pipe 16 is an inlet 60 a through which the cooling water introduced from the first supply pipe S1 flows into the cooling flow path 60 .

[0051] The rotating shaft 20 is formed in a cylindrical shape with a step on the outer diameter side. This rotating shaft 20 has a hollow portion recessed from the axial right end face toward the axial left side. The hollow portion is composed of, from the axial right side, a first small diameter hole portion 21, a large diameter hole portion 22 communicating with the first small diameter hole portion 21, and a second small diameter hole portion 23 communicating with the large diameter hole portion 22. The first small diameter hole portion 21, the large diameter hole portion 22, and the second small diameter hole portion 23 are arranged approximately coaxially.

[0052] The first small diameter hole portion 21 has a diameter slightly larger than that of the second small diameter hole portion 23. The first small diameter hole portion 21 extends in the axial direction with a substantially constant diameter and opens toward the right in the axial direction.

[0053] The large diameter hole portion 22 extends axially to the right with a substantially constant diameter, and then tapers in diameter toward the right end in the axial direction. That is, the right end of the large diameter hole portion 22 is formed with a curved surface 22 a that curves toward the right in the axial direction and toward the inner diameter side.

[0054] An inlet pipe 16 is inserted substantially coaxially into the first small diameter hole portion 21 and the large diameter hole portion 22. The outer diameter of the inlet pipe 16 is smaller than the diameters of the first small diameter hole portion 21, the large diameter hole portion 22, and the second small diameter hole portion 23.

[0055] The rotating shaft 20 and the inlet pipe 16 define a radial space therebetween. This radial space is an outlet flow passage 66 for guiding cooling water to the space sp2 that communicates with the first recovery pipe R1. The outlet flow passage 66 has an expanded diameter portion 66a located in the large diameter hole portion 22 and a reduced diameter portion 66b located in the first small diameter hole portion 21. The opening on the right side in the axial direction of the outlet flow passage 66 is an outlet 60b through which the cooling water that has flowed through the cooling flow passage 60 flows out into the space sp2.

[0056] The left end of the inlet pipe 16 is disposed within the large diameter hole portion 22. More specifically, the left end of the inlet pipe 16 is disposed slightly to the right of the boundary between the large diameter hole portion 22 and the second small diameter hole portion 23. This makes it less likely that the left end of the inlet pipe 16 will come into contact with the rotating shaft 20.

[0057] The rotating shaft 20 is also formed with eight first communication holes 25 in the circumferential direction, extending inward from the outer circumferential surface thereof and communicating with the left side of the axial center of the large diameter hole portion 22, i.e., the expanded diameter portion 66a. These first communication holes 25 are equally spaced. Note that the number and arrangement of the first communication holes 25 may be changed as appropriate.

[0058] The second small diameter holes 23 extend in the axial direction with approximately the same diameter. The second small diameter holes 23 are provided in radially overlapping positions across the axial direction of the rotor core 31 of the rotor 30. The second small diameter holes 23 are rotational shaft flow paths 62 into which the cooling water flows after passing through the inlet flow path 61.

[0059] Furthermore, eight second communication holes 26 are formed in the circumferential direction of the rotating shaft 20, extending from the outer circumferential surface toward the inner diameter side and communicating with the left end of the second small diameter hole portion 23. These second communication holes 26 are equally spaced apart. Note that the number and arrangement of the second communication holes 26 may be changed as appropriate.

[0060] The second communication hole 26 and a groove 37a in the first end plate 34 described later constitute a branch flow path 63 that guides the cooling water that has passed through the rotary shaft flow path 62 to one of the rotor flow paths 64 described later.

[0061] The rotor 30 has a rotor core 31, which is a magnetic body in this embodiment, eight permanent magnets 32 provided on the rotor core 31, eight pipes 33, a first end plate 34 arranged to the left of the rotor core 31, and a second end plate 35 arranged to the right of the rotor core 31.

[0062] 1 to 3, rotor core 31 has a through-hole that passes through its radial center in the axial direction, and is formed in a cylindrical shape that extends in the axial direction. Rotor core 31 is fitted onto rotating shaft 20. The outer diameter and inner diameter of rotor core 31 are approximately the same in the axial direction.

[0063] 1 and 2, eight permanent magnets 32 are inserted in the rotor core 31 in the axial direction. Eight pipes 33 are disposed axially penetrating the rotor core 31 on the inner diameter side of the permanent magnets 32. Both axial ends of the pipes 33 protrude axially outward from the rotor core 31 (see FIG. 1). The eight permanent magnets 32 and the eight pipes 33 are equally spaced in the circumferential direction (see FIG. 2). The pipes 33 form one of the rotor flow paths 64 into which cooling water flows after passing through grooves 37a (described later) through their through holes (see FIG. 1).

[0064] The permanent magnets 32 are formed in the shape of flat plates extending in the axial direction. As shown in Fig. 2, the radial cross section of the permanent magnets 32, i.e., the shape when viewed from the axial direction, is formed in a rectangular shape having long sides 32a and short sides 32b. The long sides 32a of the permanent magnets 32 are approximately perpendicular to the diameter direction of the rotor core 31.

[0065] The permanent magnet only needs to have a long side and a short side in its radial cross section, and the long side may be curved, wavy, or zigzag, or may be modified as appropriate.

[0066] The pipe 33 is disposed at a position where it overlaps in the radial direction with the central portion of the long side 32 a on the inner diameter side of the permanent magnet 32. In other words, the permanent magnet 32 ​​is disposed such that the central portion of its long side 32 a faces the rotor flow path 64.

[0067] 3, the rotor core 31 is configured by stacking a plurality of thin electromagnetic steel sheets 131 in the axial direction. Although not shown directly, the electromagnetic steel sheets 131 are coated with an insulating film. This reduces heat generated by eddy currents in the rotor 30.

[0068] The plurality of electromagnetic steel sheets 131 may be fixed by any known fixing method, such as by caulking or welding. The electromagnetic steel sheets 131 are exaggerated in size in FIG.

[0069] Furthermore, the plurality of electromagnetic steel sheets 131 may have gaps in the axial direction between adjacent electromagnetic steel sheets 131. With such a configuration, each electromagnetic steel sheet 131 can more easily function as a fin, thereby improving heat dissipation efficiency. On the other hand, from the viewpoint of magnetic efficiency, for rotor cores with the same axial length, it is preferable to arrange as many electromagnetic steel sheets 131 with as few gaps as possible.

[0070] In more detail, the pipe 33 has a cylindrical base 33a that is made of ceramic and has insulating properties and high thermal conductivity and extends in the axial direction, and a coating layer 33b that is made of alumina and covers the outer surface of the base 33a. Note that the materials of the base 33a and the coating layer 33b may be changed as appropriate, but are preferably materials that have insulating properties and high thermal conductivity. In addition, the illustration of the base 33a and the coating layer 33b is exaggerated in Figure 3.

[0071] 1 , the first end plate 34 has a through hole that passes through its radial center in the axial direction, and is formed in an annular shape that extends in the axial direction. The first end plate 34 is fixedly fitted onto the rotary shaft 20.

[0072] In more detail, the first end plate 34 has an annular, thin-plate-shaped inner member 36 that is arranged in abutment against the left end of the rotor core 31, and an annular, thin-plate-shaped outer member 37 that is abutted against and fixed to the left end of the inner member 36.

[0073] The inner member 36 has eight through holes that are aligned circumferentially and radially with the eight pipes 33. The left ends of the pipes 33 are fitted and fixed into each through hole. The gaps between the pipes 33 and the inner member 36 are sealed by gaskets (not shown).

[0074] The outer member 37 has eight grooves 37a recessed to the left of its right end face and extending radially. The grooves 37a are equally spaced circumferentially. Each groove 37a is open toward the right in the axial direction along the entire radial direction. Each groove 37a has a closed outer diameter end and an open inner diameter end.

[0075] The outer member 37 is fixed with its right end surface abutting against the left end surface of the inner member 36. As a result, the openings of each groove 37a that are open toward the right in the axial direction are closed, forming flow paths that extend radially. In the following description, these flow paths may also be referred to as grooves 37a.

[0076] The eight grooves 37a are aligned in the circumferential direction with the eight pipes 33 fixed to the inner member 36. The outer diameter side of each groove 37a communicates with one of the eight pipes 33 in the axial direction.

[0077] The eight grooves 37a are aligned in the circumferential direction with the eight second communication holes 26 in the rotating shaft 20. The inner diameter ends of the grooves 37a communicate with any of the eight second communication holes 26 in the radial direction.

[0078] The axial gap between the inner member 36 and the outer member 37 is sealed by an O-ring located on the outer diameter side of the groove 37a. In addition, the first end plate 34 is sealed by an O-ring radially between the inner member 36 and the rotating shaft 20 and radially between the outer member 37 and the rotating shaft 20.

[0079] This allows the first end plate 34 to stably allow the cooling water that has flowed into any of the grooves 37a to flow into the rotor flow passage 64 without flowing out into the space sp1.

[0080] The second end plate 35 has substantially the same configuration as the first end plate 34, and therefore a duplicated description will be omitted or simplified. The second end plate 35 has an inner member 38 that is fixed in contact with the right end of the rotor core 31, and an outer member 39 that is fixed in contact with the right end of the inner member 38.

[0081] The right end of the pipe 33 is fitted and fixed in the inner member 38 .

[0082] The outer member 39 has eight grooves 39a recessed rightward from the left end face thereof and extending in the radial direction. The grooves 39a are open axially leftward along the radial direction.

[0083] The outer member 39 is fixed with its left end surface abutting against the right end surface of the inner member 38. This closes the openings of the grooves 39a, forming flow paths extending in the radial direction. In the following description, these flow paths may also be referred to as grooves 39a.

[0084] The groove 39 a has an outer diameter side that communicates axially with one of the eight pipes 33. The groove 39 a also communicates radially with one of the eight second communication holes 26. The groove 39 a and the second communication holes 26 form a radial flow path 65 that guides the cooling water that has passed through the rotor flow path 64 to the outflow flow path 66.

[0085] Next, a description will be given of the cooling of the rotating shaft 20 and the rotor 30 by the cooling flow passage 60. In Fig. 1, the flow of cooling water through the cooling flow passage 60 is schematically indicated by arrows.

[0086] The cooling water that has flowed into the first supply pipe S1 flows into the inlet 60a of the cooling flow path 60 and into the inlet flow path 61. As described above, the inlet pipe 16 that constitutes the inlet flow path 61 has low thermal conductivity, so the cooling water flowing through the inlet flow path 61 does not easily exchange heat with the heated cooling water flowing through the outlet flow path 66. In other words, the temperature of the cooling water flowing through the inlet flow path 61 is easily maintained.

[0087] The cooling water that has passed through the inlet passage 61 flows into the rotating shaft passage 62. As described above, the left end of the inlet pipe 16 is located slightly to the right of the boundary between the large diameter hole portion 22 and the second small diameter hole portion 23. The radial gap between the left end of the inlet pipe 16 and the second small diameter hole portion 23 is extremely small. The cross-sectional area of ​​the rotating shaft passage 62 is also narrower than the cross-sectional area of ​​the expanded diameter portion 66a of the outlet passage 66. As a result, almost all of the cooling water that has passed through the inlet passage 61 flows into the branch passage 63.

[0088] The cooling water passing through the rotating shaft flow path 62 can cool the portion of the rotating shaft 20 on which the rotor core 31 is fitted, over the entire axial direction. This allows the rotating shaft 20 side of the rotor core 31 to be efficiently cooled over the entire axial direction.

[0089] The cooling water that flows into the left end, which is the terminal end of the rotating shaft flow passage 62, branches off and flows into eight branch flow passages 63, which are outlets of the rotating shaft flow passage 62. Because the cooling water continues to flow into the left end, which is the terminal end of the rotating shaft flow passage 62, the cooling water flows into each branch flow passage 63 almost evenly. The cooling water that flows into the branch flow passages 63 passes through the groove 37a and flows into the rotor flow passage 64.

[0090] In other words, the cooling flow passage 60 has a folded structure. This folded structure makes it easier for the cooling water to flow in one direction from the rotating shaft flow passage 62 to the rotor flow passage 64 while flowing in opposite directions in the rotating shaft flow passage 62 and the rotor flow passage 64, making it easier for the cooling water to enter the rotor flow passage 64 from the rotating shaft flow passage 62.

[0091] Although radially extending pipes may be used instead of the second communication holes 26 and grooves 37a to form part of the branch flow passages, there is a risk that the pipes may be deformed or come loose due to the action of centrifugal force or vibration of the rotating shaft 20. In this embodiment, it is preferable that the second communication holes 26 formed in the rotating shaft 20 and the grooves 37a formed in the first end plate 34 form part of the branch flow passages 63, as this allows cooling water to flow stably into the rotor flow passage 64 during operation. The same applies to the radial flow passages 65.

[0092] Furthermore, the groove 37a that constitutes part of the branch flow path 63 is formed in the first end plate 34, which functions as a retainer for the permanent magnet 32. As a result, the rotor 30 of this embodiment not only reduces the number of parts compared to when separate parts are provided, but also simplifies assembly. The same applies to the second end plate 35.

[0093] The cooling water passing through the rotor flow path 64 can cool the entire portion of the rotor through which the pipe 33 passes in the axial direction. Furthermore, since the pipe 33 is located closer to the permanent magnet 32 ​​in the radial direction than the rotation axis flow path 62, the permanent magnet 32 ​​can be cooled efficiently.

[0094] Furthermore, the pipe 33 has a base portion 33a with high thermal conductivity and a coating layer 33b, which allows efficient heat exchange between the cooling water and the rotor core 31. Furthermore, the pipe 33 has insulating properties, which makes it less likely to affect the magnetic field of the rotor core 31.

[0095] The cooling water that has passed through each rotor flow path 64 passes through the radial flow paths 65 and merges with the expanded diameter portion 66a in the outflow flow path 66. As described above, since the large diameter hole portions 22 have a larger diameter than the second small diameter hole portions 23, the rotational shaft flow path 62 formed by the expanded diameter portion 66a including the large diameter hole portions 22 and the second small diameter hole portions 23 has a stepped shape. This stepped shape makes it difficult for the cooling water to flow from the expanded diameter portion 66a into the rotational shaft flow path 62.

[0096] Furthermore, since the first small diameter hole portion 21 has a diameter slightly larger than that of the second small diameter hole portion 23, the cooling water moving toward the inner diameter side through the expanded diameter portion 66a is more likely to flow into the reduced diameter portion 66b than into the rotary shaft flow path 62.

[0097] Furthermore, the force of the water pump 2 sucking the cooling water acts on the reduced diameter portion 66b, making it easier for the cooling water to flow from the expanded diameter portion 66a to the reduced diameter portion 66b. Furthermore, the expanded diameter portion 66a has the curved surface 22a whose diameter decreases toward the reduced diameter portion 66b, making it easier for the cooling water to be guided more smoothly into the reduced diameter portion 66b.

[0098] Furthermore, because the cooling water that has moved toward the inner diameter side through the radial flow passages 65 flows into the expanded diameter portion 66a, the suction force of the water pump 2 is less likely to reach the rotary shaft flow passage 62, which is located axially to the left of the first communication hole 25, i.e., on the opposite side of the outlet 60b. In other words, it is less likely for the cooling water to flow from the rotary shaft flow passage 62 into the outlet flow passage 66.

[0099] The cooling water that has flowed into the reduced diameter portion 66b flows out into the space sp2 through the outlet 60b. The cooling water flowing into the space sp2 can cool the rotary seal ring and the stationary seal ring in the mechanical seal 50.

[0100] The cooling water that flows out into the space sp2 flows into the first recovery pipe R1 through the communication hole 14b and is recovered by the water pump 2.

[0101] As described above, in the rotating electric machine 1 of this embodiment, the inlet 60a and outlet 60b of the cooling flow passage 60 are both provided on the axial right side of the rotating shaft 20, and the cooling water flows in a reverse axial direction in the rotating shaft flow passage 62 and the rotor flow passage 64. This makes it possible to cool not only the rotating shaft 20 and its vicinity, but also the rotor core 31 of the rotor 30 directly and thereby cool the permanent magnets 32, thereby making it possible to maintain stable rotational efficiency of the rotating electric machine 1.

[0102] In this embodiment, the first supply pipe S1 is fluidly connected to the inlet pipe 16, and the first return pipe R1 is fluidly connected to the space sp2. However, this is not limiting. The first supply pipe S1 may be fluidly connected to the space sp2, and the first return pipe R1 may be fluidly connected to the inlet pipe 16. That is, the cooling water may flow in the opposite direction to that in this embodiment. Even with this configuration, the permanent magnets 32 can be efficiently cooled. However, this embodiment is preferable from the viewpoint of smoothly circulating the cooling water. The large diameter hole 22 in the rotating shaft 20 may be provided with a blade shape that functions like a partial impeller to control the flow direction of the cooling water.

[0103] Furthermore, the cooling efficiency of the permanent magnet 32 ​​is further improved because the long sides 32a thereof are disposed facing the rotor flow path 64. Furthermore, the cooling efficiency of the permanent magnet 32 ​​is further improved because the central portions of the long sides 32a thereof are disposed facing the rotor flow path 64.

[0104] Furthermore, the rotor flow passage 64 is provided along the axial direction of the rotor core 31. This allows cooling not only the permanent magnets 32 but also the entire rotor core 31, which functions as a magnet, making it easier to maintain rotational efficiency.

[0105] Furthermore, because the rotor flow path 64 is formed by the pipe 33, it is possible to form a flow path with a simple configuration that prevents the cooling water passing through it from leaking to the outside. Furthermore, the type of fluid used for cooling can be changed appropriately to match the material of the pipe.

[0106] In this embodiment, the shaft is the rotating shaft 20 and is the rotating element. In other words, the housing 10 is the stationary element. As a result, the rotating electric machine 1 does not require a brush to energize the coil 41 installed in the housing 10, which not only simplifies the structure but also prevents the generation of wear powder and frictional heat caused by the brush. Furthermore, because the coil 41 is part of the stator 40, vibrations caused by rotation are less likely to affect the coil 41 compared to a configuration in which a coil is provided on the rotor side, and adverse effects such as unevenness or unraveling of the winding of the coil 41 are less likely to occur.

[0107] Furthermore, since the housing 10 is provided with a stator cooling passage 70, the stator 40 side of the rotor core 31 can also be cooled.

[0108] In addition, the mechanical seal 50 seals the space between sp1 and sp2, preventing the cooling water from directly adhering to the rotor core 31 or the coil 41, allowing the type of fluid used for cooling to be changed as appropriate.

[0109] Note that, as long as the space between the spaces sp1 and sp2 can be sealed, a lip seal may be used instead of the mechanical seal 50, and the type of seal may be changed as appropriate.

[0110] Furthermore, since the rotating electrical machine 1 is cooled by the radiator 3 and has a structure in which the rotating shaft 20 and rotor core 31 can be cooled by the cooling water delivered by the water pump 2, when applied to an automobile, for example, an existing water pump and radiator can be used. In other words, a pump and cooling device dedicated to the rotating electrical machine 1 can be omitted.

[0111] In addition, since the inlet 60a and outlet 60b of the cooling flow path 60 are located on the right side of the rotating shaft 20, another mechanism such as a reducer can be easily attached to the left end of the rotating shaft 20.

[0112] In this embodiment, the configuration in which the pipes 33 are disposed radially inward of the permanent magnets 32 in the rotor core 31 has been described, but the pipes 33 may be provided between circumferentially adjacent permanent magnets 32, as in the rotor core 231 of the embodiment shown in Fig. 4. While such a configuration can also cool the permanent magnets 32, the present embodiment is preferable from the viewpoint of being able to cool the permanent magnets 32 efficiently.

[0113] In this way, the positional relationship between each permanent magnet and each pipe in the rotor core may be changed as appropriate. Although not shown directly in the drawings, the pipe 33 may be disposed radially outward of the permanent magnet 32, or the pipe 33 may penetrate the permanent magnet 32 ​​in the axial direction. However, from the viewpoint of magnetic flux transmission, this embodiment is preferable.

[0114] Second Embodiment Next, a rotating electrical machine according to a second embodiment will be described with reference to Fig. 5. Note that a description of the same configuration as in the previous embodiment will be omitted.

[0115] 5 , in a rotating electric machine 301 according to the second embodiment, a labyrinth seal 380 is provided at the left end of the large diameter hole portion 22 in the rotating shaft 20. The left end of the inlet pipe 16 is disposed radially inward of this labyrinth seal 380. With this configuration, movement of cooling water between the rotating shaft flow path 62 and the outlet flow path 66 can be more reliably prevented.

[0116] Note that, as long as it is possible to prevent the movement of cooling water between the rotary shaft passage 62 and the outlet passage 66, a mechanical seal may be used instead of the labyrinth seal, and the type of seal may be changed as appropriate.

[0117] Next, a rotating electrical machine according to a third embodiment will be described with reference to Fig. 6. Note that a description of the same configuration as in the previous embodiment will be omitted.

[0118] As shown in Fig. 6 , in the rotating electric machine of the third embodiment, the pipe 533 extends from the groove 37a side toward the groove 39a side, tilting toward the upstream side in the direction of rotation. In other words, the circumferential phases of both ends of the pipe 533 are different. Note that in Fig. 6 , some elements are omitted or simplified in order to clearly show that the pipe 533 is tilted. Also, although the radial positions of both ends of the pipe 533 have been described as being the same, they may be different.

[0119] As a result, the cooling water flowing through rotor flow path 564 of cooling flow path 560 is subjected not only to the delivery and suction forces of water pump 2 but also to the rotational force of rotating rotor 530, promoting the flow of the cooling water toward 39a, thereby making the circulation of the cooling water more efficient.

[0120] Next, a rotating electrical machine according to a fourth embodiment will be described with reference to Fig. 7. Note that a description of the same configuration as in the previous embodiment will be omitted.

[0121] 7, the cooling flow path 760 in the rotating electric machine 701 of the fourth embodiment differs from that of the first embodiment in that the cross-sectional areas of the rotational axis flow path 762 provided in the rotating shaft 720, the branch flow path 763, the rotor flow path 764 provided in the rotor 730, and the radial flow path 765 are expanded toward the downstream side in the flow direction of the cooling water. As a result, the flow velocity of the cooling water tends to decrease toward the downstream side, which makes it easier for the cooling water to smoothly flow into other flow paths located downstream.

[0122] Although the embodiments of the present invention have been described above with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention also includes modifications and additions that do not deviate from the gist of the present invention.

[0123] For example, in the first to fourth embodiments, the rotating electrical machine has been described as having both a cooling flow path and a stator cooling flow path, but this is not limited thereto, and the rotating electrical machine may have only a cooling flow path.

[0124] In addition, in the first to fourth embodiments, the rotating shaft passage is described as extending in the axial direction of the rotor core, but this is not limited thereto, and the rotating shaft passage may be provided at a position where it overlaps with at least a portion of the rotor core in the radial direction, or may extend in the axial direction of the rotor, or may be modified as appropriate. On the other hand, from the viewpoint of maintaining magnetic efficiency, it is preferable that the rotating shaft passage extends at least in the axial direction of the rotor core.

[0125] Furthermore, in Examples 1 to 4, the rotor flow path has been described as extending in the axial direction of the rotor core, but this is not limited to this, and it may be located in a position that overlaps radially with at least a portion of the rotor core, or it may extend in the axial direction of the rotor, in other words, it may pass through the rotor, or it may be changed as appropriate.

[0126] On the other hand, from the viewpoint of maintaining magnetic efficiency, it is preferable that the rotor flow passage extend at least in the axial direction of the rotor core. Also, if the rotor flow passage penetrates the rotor, it is necessary to provide a flow passage that communicates with the rotating shaft flow passage axially outside the rotor. The rotor flow passages of Examples 1 to 4 are preferable from the viewpoint of making it easier to make the structure compact.

[0127] Furthermore, in the first to fourth embodiments, the rotor flow passage is formed in a plurality of parts, but the present invention is not limited to this and may have only one part.

[0128] In addition, in the first to fourth embodiments, the rotor flow passage is described as being configured by a pipe, but this is not limited thereto, and the rotor flow passage may be a hole provided in at least a part of the rotor core, and the configuration may be changed as appropriate. On the other hand, configuring the rotor flow passage by a pipe is preferable in that it is possible to easily configure a flow passage that does not leak the cooling fluid to the outside.

[0129] In addition, in the first to fourth embodiments, the number of rotor flow passages and the number of permanent magnets are the same, but this is not limiting, and the number of rotor flow passages and the number of permanent magnets may be different. For example, the number of permanent magnets may be twice the number of rotor flow passages, and two permanent magnets may be arranged in a V-shape with their long sides facing each other relative to one rotor flow passage.

[0130] In addition, in the above-described first to fourth embodiments, the rotor core is described as being made up of a plurality of electromagnetic steel plates, but this is not limited to this and may be, for example, a single iron core, or may be modified as appropriate.

[0131] In addition, in the first to fourth embodiments, the inlet pipe is not inserted into the rotary shaft passage, but the present invention is not limited to this configuration and may be inserted into the rotary shaft passage. This configuration makes it easier to prevent backflow from the rotary shaft passage toward the outlet. On the other hand, from the viewpoint of preventing contact between the inlet pipe and the rotary shaft, the first to fourth embodiments are preferable.

[0132] Furthermore, in Examples 1 to 4, the stator cooling flow path was described as a spiral flow path, but this is not limited to this. For example, at least one flow path extending linearly from the inlet to the outlet may be formed, and the structure may be modified as appropriate.

[0133] Furthermore, in the above-described Examples 1 to 4, a structure was described in which the shaft is the rotating axis, which is the rotating element, the permanent magnets and magnetic bodies installed on the shaft side are part of the rotor, the housing is the stationary element, and the coils installed on the housing side are part of the stator, but this is not limited to this, and the shaft may be a fixed axis, which is the stationary element, the permanent magnets and magnetic bodies installed on the shaft side are part of the stator, the housing is the rotating element, and the coils installed on the housing side are part of the rotor.

[0134] REFERENCE SIGNS LIST 1 Rotating electric machine 10 Housing 12 Cylindrical material (water jacket) 16 Inflow pipe 20 Rotating shaft (shaft) 30 Rotor 31 Rotor core (magnetic material) 32 Permanent magnet 32a Long side 32b Short side 33 Pipe 40 Stator 41 Coil 50 Mechanical seal (seal) 60 Cooling flow passage 60a Inlet 60b Outlet 62 Rotating shaft flow passage (shaft flow passage) 64 Rotor flow passage (magnetic material flow passage) 66 Outlet flow passage 66a Enlarged diameter portion 70 Stator cooling flow passage (coil cooling flow passage) 131 Electromagnetic steel plate 231 Rotor core 301 Rotating electric machine 380 Labyrinth seal 530 Rotor 533 Pipe 560 Cooling flow passage 564 Rotor flow passage 701 Rotating electric machine 720 Rotating shaft 760 Cooling flow path 762 Rotational shaft flow path 764 Rotor flow path sp1 Space (space in which the rotor is arranged) sp2 Space (space communicating with the outlet)

Claims

1. A rotating electric machine comprising a coil installed on the housing side, and a permanent magnet and a magnetic body installed on the shaft side that is rotatable relative to the housing, the rotating electric machine having a cooling flow path with an inlet and an outlet on one axial side of the shaft, the cooling flow path having a shaft flow path that extends axially through at least a portion of the shaft, and a magnetic body flow path that communicates axially with at least a portion of the magnetic body.

2. A rotating electric machine according to claim 1, wherein the magnetic material flow passage is provided closer to the permanent magnet than the shaft.

3. A rotating electric machine according to claim 1, wherein the permanent magnet has a radial cross section having a long side and a short side, and the long side is disposed opposite the magnetic flow path.

4. A rotating electric machine according to any one of claims 1 to 3, wherein the magnetic material flow path is provided across at least the magnetic material.

5. A rotating electric machine according to claim 1, wherein the magnetic material flow path is formed by a pipe.

6. A rotating electric machine according to claim 1, wherein the magnetic body is made up of a plurality of electromagnetic steel plates stacked in the axial direction.

7. A rotating electric machine as described in claim 1, wherein the shaft is a rotating shaft that rotates relative to the housing, the housing has an inlet pipe inserted into the rotating shaft and communicating with the inlet, the radial gap between the inlet pipe and the rotating shaft is an outlet flow path communicating with the outlet, and the outlet flow path has a larger diameter than the shaft flow path and includes an expanded diameter portion where the shaft flow path and the magnetic material flow path communicate with each other.

8. A rotating electric machine according to claim 7, wherein the outlet flow passage has a diameter larger than that of the shaft flow passage.

9. A rotating electric machine according to claim 1, wherein the shaft flow passage extends in the axial direction of the magnetic body.

10. A rotating electric machine according to claim 1, wherein the housing is provided with a coil cooling passage surrounding the coil.

11. A rotating electric machine according to claim 1, wherein the space inside the housing in which the magnetic body is disposed and the space communicating with the outlet are sealed with a seal.

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