Cooling structure of rotary machine

Abstract

To provide a cooling structure of a rotary machine capable of reducing the size and weight of the rotary machine itself while securing cooling of the rotary machine during operation, and achieving stable pump operation in a cooling pump.SOLUTION: The cooling structure of the motor for cooling the motor 1 having a shaft 3 extending around a predetermined axis V and along the axis V during its operation includes a cooling pump 7 which is arranged on the axis V in a housing 8 of the motor 1 and operates by rotating integrally with the shaft 3 to circulate cooling oil for cooling the motor 1. One of the lower surface 60 of the 43a of the main body portion of the relative rotating member 43 and the 44a of the upper surface of the inner rotor 44 is provided with a recess 61 or a coolant reservoir 62 as a coolant reservoir for forming an oil film for lubrication between the lower surface 60 and the 44a of the upper surface.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a cooling structure for a rotating machine, and relates to a cooling structure for a rotating machine that is applied to a rotating machine such as a motor that drives the rotor of a drone, and that cools the rotating machine during operation. [Background technology]

[0002] Conventionally, cooling structures for this type of rotating machine are known, for example, from Patent Documents 1 and 2. The rotating machine in Patent Document 1 is an axial gap type rotating electric machine, and includes a rotor attached to a rotating shaft passing through the rotor, a stator disposed relative to the rotor across a gap in the axial direction of the rotating shaft, and a case that houses the rotor and stator. The case is provided with an inlet port for introducing coolant and an outlet port for discharging coolant, which communicate the inside and outside of the case. As a result, the coolant introduced through the inlet port cools the stator inside the case, and the coolant that has exchanged heat with the stator is discharged to the outside via the outlet port.

[0003] On the other hand, the rotating machine of Patent Document 2 is a drive device consisting of a radial motor, and includes a rotor attached to the motor shaft with the motor shaft passing through it, a stator disposed radially apart from the rotor, a housing accommodating the rotor and stator, a pump section provided within the housing for circulating cooling oil within the housing, and a transmission member for transmitting rotation of the motor shaft to the pump section. The pump section includes a pump shaft disposed parallel to the motor shaft, an external gear fixed to the lower end of the pump shaft and having multiple teeth on its outer periphery, and a ring-shaped internal gear having multiple teeth on its inner periphery and meshing with the external gear, forming a trochoid pump. The transmission member has two meshing gears, and rotation of the motor shaft is transmitted to the pump shaft via the two gears, thereby operating the pump section. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-99181 [Patent Document 2] Patent No. 6947181 Summary of the Invention [Problem to be solved by the invention]

[0005] In the rotating machine of Patent Document 1, a pump located outside the rotating machine circulates the coolant inside and outside the rotating machine via an inlet port and an outlet port provided in the case. This requires a drive source to drive the pump, and also increases the size of the cooling structure of the rotating machine, including the pump.

[0006] On the other hand, in the rotating machine of Patent Document 2, the pump section is driven by the rotation of the motor shaft of the rotating machine itself, and therefore a dedicated drive source for the pump section is not required, unlike the rotating machine of Patent Document 1. However, in the rotating machine of Patent Document 2, the pump shaft of the pump section is disposed at a distance in the radial direction from the motor shaft, so a transmission member made up of gears is necessary, which makes the rotating machine itself larger and heavier.

[0007] Furthermore, in the rotating machine of Patent Document 2, the side surfaces of the external gear and internal gear in the pump section may come into sliding contact with a partition wall inside the housing during operation. In such cases, friction generated between the side surfaces of the external gear and internal gear and the partition wall inside the housing acts as resistance to the operation of the pump section, which may result in unstable pump operation.

[0008] The present invention has been made to solve the above-mentioned problems, and aims to provide a cooling structure for a rotating machine that can make the rotating machine itself more compact and lightweight while ensuring cooling of the rotating machine during operation, and that can achieve stable pump operation in a cooling pump. [Means for solving the problem]

[0009] In order to achieve the above object, the invention of claim 1 provides a cooling structure for a rotating machine that cools a rotating machine having a rotating shaft centered on a predetermined axis and extending along the axis during operation, the cooling structure including a cooling pump disposed on the axis within a housing of the rotating machine and operating by rotating integrally with the rotating shaft to circulate a refrigerant for cooling the rotating machine, the rotating shaft having a predetermined length extending along the axis, a predetermined diameter, and a hole opening into the housing, the hole having a relative rotating member disposed in the hole that can rotate relatively to the rotating shaft about the axis, the relative rotating member extending along the axis. a cooling structure for a rotating machine, characterized in that the cooling pump has a cylindrical main body, and an eccentric protrusion that protrudes from the end face of the main body toward the opening of the hole and extends around an eccentric axis that is radially shifted from the axis, the cooling pump having an outer rotor with multiple teeth along the inner surface of the opening in the rotating shaft, and an inner rotor that is rotatably supported on the eccentric protrusion, has its outer peripheral portion meshing with the outer rotor, and has its side facing the end face of the main body in close proximity, the end face of the main body being a relative rotating member, and one of the side faces of the inner rotor has a refrigerant reservoir portion for retaining refrigerant and forming a lubricating oil film between the end face and the side face.

[0010] According to this configuration, a cooling pump is disposed on the axis within the housing of the rotating machine, and operates by rotating integrally with the rotating shaft. The cooling pump also includes an outer rotor portion provided on the inner circumferential surface of the opening of the rotating shaft and an inner rotor meshed therewith, the inner rotor being rotatably mounted on the eccentric protrusion of the relative rotation member, which is rotatable relative to the rotating shaft. In other words, the cooling pump is an internal gear pump formed by the outer rotor portion and the inner rotor, and as the outer rotor portion rotates integrally with the rotation of the rotating shaft in a predetermined direction, the meshed inner rotor rotates in the same direction as the outer rotor portion, thereby performing pumping operation. Therefore, according to the present invention, the rotating machine itself can be made more compact and lightweight than conventional cooling structures that include a pump that circulates coolant outside the rotating machine or that arrange the pump shaft radially apart from the motor shaft.

[0011] The inner rotor, which is rotatably supported on the eccentric protrusion of the relative rotating member, has its side surface facing and proximate to the end surface of the main body of the relative rotating member. A refrigerant reservoir is provided on one of the end surface of the main body of the relative rotating member and the side surface of the inner rotor. By using cooling oil, for example, as the refrigerant, a lubricating oil film is formed between the end surface of the main body and the side surface of the inner rotor while the cooling oil is retained in the refrigerant reservoir. This ensures stable rotation of the inner rotor while preventing seizure due to sliding between the end surface of the main body and the side surface of the inner rotor when the cooling pump rotates in conjunction with the operation of the rotating machine, thereby achieving stable pumping operation of the cooling pump.

[0012] The invention of claim 2 is characterized in that, in the cooling structure of the rotating machine described in claim 1, the refrigerant reservoir portion is provided on the end surface of the main body portion and is formed in a concave shape that opens toward the side surface of the inner rotor.

[0013] With this configuration, the refrigerant reservoir provided on the end face of the main body is formed in a recess that opens toward the side face of the inner rotor, making it relatively easy to form the refrigerant reservoir itself on the end face of the main body.Furthermore, since the refrigerant reservoir can hold its volume of refrigerant, refrigerant is supplied from the refrigerant reservoir to the gap between the end face of the main body and the side face of the inner rotor, making it easy to form a lubricating oil film in the gap.

[0014] The invention of claim 3 is characterized in that, in the cooling structure of a rotating machine described in claim 2, the refrigerant reservoir portion is composed of a plurality of recesses arranged at intervals from each other, each having a predetermined diameter and depth.

[0015] With this configuration, the refrigerant reservoir is made up of multiple recesses, and by setting the size and number of the recesses depending on the amount of refrigerant to be stored in the refrigerant reservoir and the shape of the oil film to be formed, an appropriate oil film can be formed in the gap between the end face of the main body and the side face of the inner rotor.

[0016] The invention of claim 4 is characterized in that, in the cooling structure of a rotating machine described in claim 2, the refrigerant reservoir has a reservoir main body that stores most of the refrigerant to be held in the refrigerant reservoir, and a refrigerant outflow portion that communicates with this reservoir main body, protrudes in the direction in which the inner rotor rotates, and is formed narrower than the reservoir main body.

[0017] With this configuration, most of the refrigerant to be held in the refrigerant reservoir is stored in the reservoir body, and the refrigerant outlet port, which communicates with the reservoir body, protrudes in the direction of rotation of the inner rotor and is narrower than the reservoir body. As a result, when the inner rotor rotates during operation of the cooling pump, the refrigerant stored in the reservoir body is sent to the refrigerant outlet port through the side surface of the rotating inner rotor, increasing the pressure of the refrigerant passing through the refrigerant outlet port. As a result, during operation of the cooling pump, refrigerant at a relatively high pressure is supplied from the refrigerant outlet port to the gap between the end face of the main body and the side surface of the inner rotor, forming a stable lubricating oil film in the gap.

[0018] The invention of claim 5 is characterized in that, in the cooling structure of a rotating machine described in any one of claims 1 to 4, the rotating machine further has a rotor that can rotate integrally with the rotating shaft with the rotating shaft passing through it, and a stator that is arranged radially outside the rotating shaft and spaced a predetermined distance axially from the rotor, and further has a refrigerant pipe that is exposed to the outside from the housing and through which the refrigerant flows when circulating the refrigerant between the cooling pump and the stator.

[0019] According to this configuration, the rotating machine has the rotor and stator described above, and the stator is disposed radially outward of the rotating shaft with a predetermined axial gap from the rotor. That is, since the rotating machine is an axial gap type rotating machine, the rotating machine can be made more compact and generate higher torque than a radial type rotating machine in which the rotor and stator have a gap in the radial direction of the rotating shaft. Furthermore, since the refrigerant that cools the rotating machine circulates between the cooling pump and the stator, the stator, which generates heat during operation of the rotating machine, can be effectively cooled. Furthermore, since the refrigerant pipe through which the refrigerant flows is exposed to the outside from the housing, the temperature of the refrigerant can be easily lowered by heat exchange with outside air as the refrigerant flows through the refrigerant pipe.

[0020] The invention of claim 6 is characterized in that, in the cooling structure of a rotating machine described in claim 5, the main body of the relative rotating member has a first guide flow path that guides the refrigerant discharged from the cooling pump into the interior of the rotating shaft, and the rotating shaft has a second guide flow path that extends radially and is configured to communicate the inside and outside of the rotating shaft, and guides the refrigerant guided into the rotating shaft to the stator.

[0021] According to this configuration, when the cooling pump operates in response to rotation of the rotating shaft, the refrigerant sucked in and discharged by the cooling pump is guided into the interior of the rotating shaft via the first guide passage in the main body of the relative rotating member. The refrigerant guided into the rotating shaft is then guided to the stator via the second guide passage that extends radially of the rotating shaft and connects the interior and exterior of the rotating shaft. In this way, the pumping action of the cooling pump guides the refrigerant from the interior of the rotating shaft toward the radially outer side, enabling efficient cooling of the stator. [Brief explanation of the drawings]

[0022] [Figure 1] 1A and 1B are diagrams for explaining the cooling structure of a rotating machine according to one embodiment of the present invention, in which (a) is a longitudinal cross-sectional view of a motor to which the cooling structure is applied, which drives the rotor of a drone, (b) is an enlarged view of the rotating shaft of the motor in (a) and its surroundings, (c) is a cross-sectional view along line cc of the motor in (a), and (d) is a cross-sectional view along line dd of the motor in (a). [Figure 2] 10A and 10B are diagrams for explaining the relative rotation member inside the rotating shaft, in which (a) is a perspective view of the relative rotation member as seen from below, and (b) is a diagram of the lower surface of the main body of the relative rotation member as seen from below. [Figure 3] 1(a) to 1(d), respectively, and are diagrams for explaining the flow of cooling oil circulating when the motor is operating. [Figure 4] 2(a) is a diagram illustrating a modified example of the refrigerant reservoir of the present invention, similar to FIG. 2(b), showing the underside of the main body of the relative rotation member as viewed from below, and FIG. 2(b) is a diagram illustrating the outflow of cooling oil from the cooling oil reservoir of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0023] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. Figure 1 is a diagram for explaining a cooling structure for a rotating machine according to one embodiment of the present invention, and (a) shows a longitudinal cross-sectional view of a motor to which the cooling structure is applied, for example, for driving the rotor of a drone.

[0024] As shown in Figure 1(a), this motor 1 (rotating machine) is placed below the rotor 2 of a drone (not shown) and drives the rotor 2 to rotate around a vertical axis V (a predetermined axis). The rotor 2 has multiple blades that extend horizontally a predetermined length from the center, and the center is fixed to the upper end of the shaft 3 of the motor 1, which will be described later.

[0025] The motor 1 is an axial gap type motor and comprises a shaft 3 (rotating shaft) extending a predetermined length along a vertical axis V and formed in a predetermined shape, two upper and lower rotors 4 and 5 fixed to the shaft 3 with the shaft 3 passing through and rotatable integrally with the shaft 3, a stator 6 arranged between the rotors 4 and 5 with the shaft 3 inserted therethrough, a cooling pump 7 provided below the shaft 3 for circulating cooling oil (refrigerant) to cool the motor 1, and a housing 8 that accommodates the shaft 3, the rotors 4 and 5, the stator 6 and the cooling pump 7.

[0026] The shaft 3 is formed into a predetermined shape that extends vertically, and is provided so as to protrude upward from an opening 8a provided in the ceiling wall of the housing 8. The lower part of the shaft 3 is rotatably supported by an outer rotor holding part 23 (described later) via a shaft bearing 10 consisting of a thrust bearing. The internal configuration of the shaft 3 will be described later.

[0027] The upper and lower rotors 4, 5 are configured to be symmetrical with respect to each other in the vertical direction and are arranged at a predetermined distance in the vertical direction. In the following description, the upper rotor 4 will be referred to as the "upper rotor 4" and the lower rotor 5 will be referred to as the "lower rotor 5" as appropriate.

[0028] The upper rotor 4 has a disk-shaped rotor core 4a with a through-hole in the center, and a plurality of permanent magnets 4b (only two are shown in FIG. 1(a)) fixed to the underside of the rotor core 4a and arranged along the circumferential direction. On the other hand, the lower rotor 5 has a rotor core 5a similar to the rotor core 4a, and a plurality of permanent magnets 5b (only two are shown in FIG. 1(a)) fixed to the upper surface of the rotor core 5a and arranged along the circumferential direction.

[0029] The upper rotor 4 is fixed to the shaft 3 via a through hole in the rotor core 4a, and is rotatably provided within the housing 8 via an upper bearing 11 made of a radial bearing. On the other hand, the lower rotor 5, like the upper rotor 4, is fixed to the shaft 3, and is rotatably provided within the housing 8 via a lower bearing 12 made of a radial bearing.

[0030] 1(a) and 1(b), the stator 6 has a predetermined thickness in the vertical direction and includes a box-shaped stator core 6a formed in a doughnut-like shape when viewed from above, and a plurality of coils 6b (12 in FIG. 1(c)) arranged circumferentially and exposed from an upper wall 6au and a lower wall 6ad of the stator core 6a. The stator 6 faces the upper rotor 4 and the lower rotor 5 in the vertical direction, and more specifically, each coil 6b of the stator 6 faces a permanent magnet 4b of the upper rotor 4 and a permanent magnet 5b of the lower rotor 5, with a predetermined gap therebetween.

[0031] The stator 6 has a stator core 6a that is rotatably connected to the shaft 3 via two upper and lower bearings. Specifically, the stator core 6a has an upper wall 6au and a lower wall 6ad, both of which have a doughnut-shaped planar shape, and these upper wall 6au and lower wall 6ad are rotatably connected to the shaft 3 via an upper bearing 13 and a lower bearing 14, both of which are radial bearings. The upper bearing 13 and the lower bearing 14 have a predetermined sealing property so that cooling oil does not leak from inside the stator core 6a to the outside.

[0032] 1(b) and 1(d), the cooling pump 7 includes an outer rotor 42 provided at the lower end of the shaft 3, an outer rotor holder 23 provided in the housing 8 and rotatably holding the lower end of the shaft 3 having the outer rotor 42, and an inner rotor 44 rotatably supported by a relative rotation member 43 (described later) and disposed inside the outer rotor 42 while meshing with it.

[0033] The outer rotor portion 42 has a plurality of teeth (six in FIG. 1(d)) that are arranged circumferentially and each protrude inward on the lower end of the shaft 3, specifically, on the inner circumferential surface of the opening of the hole portion 41. On the other hand, the inner rotor 44 is formed to have a predetermined thickness and outer diameter, and has a plurality of teeth (five in FIG. 1(d)) that are arranged along the outer circumferential surface and each protrude outward, with the number of teeth being one less than that of the outer rotor portion 42. Note that in FIG. 1(d) (including FIG. 3(d)), hatching has been omitted from the center of the inner rotor 44 for the sake of convenience in order to show the vertical axis V and the eccentric axis E, which will be described later.

[0034] 1(a) and 1(b), a hole 41 is provided inside the shaft 3. The hole 41 extends a predetermined length along the vertical axis V, has a predetermined diameter, and opens toward the inside of the housing 8, i.e., downward from the shaft 3. The outer rotor 42 is provided on the inner circumferential surface of the opening at the lower end of the hole 41. The hole 41 also includes a relative rotation member 43 that is rotatable relative to the shaft 3 around the vertical axis V.

[0035] As shown in FIG. 1(b), the relative rotation member 43 has a main body portion 43a formed in a cylindrical shape having a predetermined length and diameter, and an eccentric protruding portion 43b formed in a cylindrical shape having a predetermined diameter smaller than that of the lower surface 60 of the main body portion 43a, protruding downward a predetermined length from a lower surface 60 (end surface) of the main body portion 43a while being slightly offset in the radial direction.

[0036] A main body 43a of the relative rotation member 43 is rotatably supported within the hole 41 via two bearings, an upper bearing 45 and a lower bearing 46, both of which are radial bearings, with a predetermined distance between the main body 43a and the ceiling surface 41a of the hole 41 of the shaft 3. A guide flow path 43c (first guide flow path) that penetrates the main body 43a in the vertical direction and guides the cooling oil upward is provided at a predetermined position of the main body 43a.

[0037] On the other hand, the eccentric protrusion 43b of the relative rotation member 43 protrudes downward from the lower surface 60 of the main body 43a around an eccentric axis E that is parallel to the vertical axis V and displaced radially, and is loosely inserted into the center of the inner rotor 44 to rotatably support it. Furthermore, the eccentric protrusion 43b penetrates the bottom wall 24 of the outer rotor holding portion 23, and its lower end is supported by a support recess 8c provided in the bottom wall 8b of the housing 8.

[0038] The inner rotor 44 is disposed in a state sandwiched between the lower surface 60 of the main body 43a of the relative rotation member 43 and the upper surface 24c of the bottom wall 24 of the outer rotor holding portion 23. Specifically, the upper surface 44a, which is the upper side surface of the inner rotor 44, faces the lower surface 60 of the main body 43a of the relative rotation member 43 in close proximity to it, while the lower surface 44b, which is the lower side surface of the inner rotor 44, rests on the upper surface 24c of the bottom wall 24 of the outer rotor holding portion 23.

[0039] 2(a) is a perspective view of the relative rotation member 43 as viewed from below, and FIG. 2(b) is a view of the lower surface of the main body 43a of the relative rotation member 43 as viewed from below. As shown in both figures, the lower surface of the main body 43a is provided with a plurality of (eight in FIG. 2(b)) recesses 61 (refrigerant reservoirs) as the refrigerant reservoir of the present invention. Each recess 61 is formed in a concave shape that opens downward and is arranged at intervals from one another so as to surround the eccentric protrusion 43b. Each recess 61 is formed in a hemispherical shape with a predetermined diameter and depth, and is configured to temporarily store cooling oil that has flowed into it.

[0040] 1(b), a temporary cooling oil reservoir 47 for temporarily storing cooling oil is provided between the relative rotation member 43 configured as described above and the ceiling surface 41a of the hole 41 of the shaft 3. The shaft 3 is provided with a guide flow path 48 (second guide flow path) that extends radially of the vertical axis V and connects the temporary cooling oil reservoir 47 with the inside of the stator 6.

[0041] 1(b) and 1(d), the outer rotor holding portion 23 has a recess 23a having approximately the same diameter as the outer diameter of the lower end of the shaft 3, and the lower end of the shaft 3 is housed in this recess 23a so as to be rotatable about the vertical axis V. In addition, a bottom wall 24 of the outer rotor holding portion 23 is provided with an intake port 24a that penetrates in the vertical direction and is used to draw in cooling oil.

[0042] 1(a) and 1(b), a cooling oil reservoir 25 for storing cooling oil is provided within the housing 8 between the bottom wall 8b and the outer rotor holding portion 23. The intake port 24a is provided to face this cooling oil reservoir 25.

[0043] 1(a), the motor 1 is provided with two cooling oil pipes 27, 28 (refrigerant pipes) arranged substantially symmetrically on the left and right sides for circulating cooling oil, and are exposed to the outside of the housing 8. The first cooling oil pipe 27 on the left side and the second cooling oil pipe 28 on the right side shown in FIG. 1(a) are both attached to the side wall of the housing 8 so as to communicate between the stator core 6a and the cooling oil reservoir chamber 25 inside the housing 8.

[0044] Next, we will explain the flow of cooling oil during operation of the motor 1 configured as above. Figures 3(a) to 3(d) correspond to the above-mentioned Figures 1(a) to 1(d), respectively, and the flow of cooling oil is indicated by arrows.

[0045] When electricity is supplied to the motor 1 from an external source and a current flows through each coil 6b of the stator 6, the shaft 3 rotates in a predetermined direction together with the upper rotor 4 and the lower rotor 5. As a result, the rotor blades 2 fixed to the shaft 3 also rotate in the same direction as the shaft 3.

[0046] In this case, the rotation of the shaft 3 activates the cooling pump 7 in the housing 8, thereby cooling the stator 6 of the motor 1 with the circulating cooling oil. Specifically, when the shaft 3 rotates, for example, clockwise when viewed from above, the outer rotor portion 42 rotates clockwise together with the shaft 3 about the vertical axis V, as shown by the outline arrow in FIG. 3(d). Accordingly, the inner rotor 44, which meshes with the outer rotor portion 42, rotates in the same direction as the outer rotor portion 42 about the eccentric axis E. As a result, in the cooling pump 7, cooling oil is drawn upward from the cooling oil reservoir chamber 25 through the intake port 24a and discharged upward into the guide flow passage 43c of the relative rotation member 43. In this case, the relative rotation member 43 is held stationary.

[0047] The cooling oil delivered by the cooling pump 7 to the guide flow path 43c of the relative rotation member 43 flows upward within the guide flow path 43c and is stored in the temporary cooling oil storage section 47. The cooling oil delivered to the temporary cooling oil storage section 47 then circulates in the motor 1 as follows.

[0048] 3(a) and 3(b), the cooling oil sent from the cooling pump 7 to the temporary cooling oil reservoir 47 through the guide passage 43c of the relative rotation member 43 flows through the guide passage 48 of the shaft 3 to the radially outer side of the shaft 3, i.e., into the stator core 6a of the stator 6. In this case, as shown in FIG. 3(c), the cooling oil flows radially outward from the shaft 3 and between the adjacent coils 6b, 6b, and then flows into the first cooling oil pipe 27 and the second cooling oil pipe 28. Then, as shown in FIG. 3(a), the cooling oil that has flowed through both cooling oil pipes 27 and 28 flows into the cooling oil reservoir 25 in the housing 8 and is sucked back into the cooling pump 7 through the intake port 24a.

[0049] As described above, the cooling oil circulates in the motor 1 and exchanges heat with each of the coils 6b of the stator 6, thereby effectively cooling each of the coils 6b.

[0050] Furthermore, when the cooling pump 7 is operating, a portion of the cooling oil drawn in from the intake port 24a flows into the recesses 61 in the lower surface 60 of the main body 43a of the relative rotation member 43. In this case, the cooling oil is retained in the recesses 61, and is supplied from the recesses 61 to the gap between the lower surface 60 of the main body 43a and the upper surface 44a of the inner rotor 44, forming a lubricating oil film in the gap.

[0051] As described above in detail, according to this embodiment, the cooling pump 7 that rotates integrally with the shaft 3 is disposed within the housing 8 of the motor 1, making it possible to make the motor 1 itself, including the cooling pump 7, more compact and lightweight than conventional motors. Furthermore, because an axial gap type is used as the motor 1, the motor 1 can be made even more compact and can obtain higher torque than a radial type. Furthermore, because an internal gear pump having an outer rotor portion 42 and an inner rotor 44 is used as the cooling pump 7, the cooling pump can be made compact.

[0052] Furthermore, when the cooling pump 7 is operating in conjunction with the operation of the motor 1, as the inner rotor 44 rotates, a lubricating oil film is formed between the lower surface 60 of the main body 43a of the relative rotating member 43 and the upper surface 44a of the inner rotor 44. This prevents seizure and other problems that may occur due to sliding between the lower surface 60 of the main body 43a and the upper surface 44a of the inner rotor 44, ensuring stable rotation of the inner rotor 44 and enabling stable pumping operation in the cooling pump 7.

[0053] Next, a modified example of the refrigerant reservoir of the present invention will be described with reference to Fig. 4. Fig. 4(a) is a view similar to Fig. 2(b) and shows, as the refrigerant reservoir of the present invention, a cooling oil reservoir 62 (refrigerant reservoir) formed in a predetermined shape whose planar shape is larger than that of the recess 61. As shown in Fig. 4(a), the cooling oil reservoir 62 has a reservoir main body 62a that opens downward (toward the surface in Fig. 4(a)), is formed in a wide predetermined shape, and has a relatively shallow predetermined depth, and a cooling oil outflow portion 62b (refrigerant outflow portion) that communicates with the reservoir main body 62a, protrudes in a predetermined direction (clockwise in Fig. 4(a)), and is formed narrower than the reservoir main body 62a.

[0054] Like the recess 61 described above, the cooling oil reservoir 62 configured as described above receives a portion of the cooling oil drawn in through the intake port 24a during operation of the cooling pump 7. Most of the cooling oil to be stored in the cooling oil reservoir 62 is stored in the reservoir main body 62a. When the inner rotor 44 rotates during operation of the cooling pump 7, the cooling oil stored in the reservoir main body 62a is pumped out toward the cooling oil outlet 62b (the lower side in FIG. 4(a) ) via the upper surface 44a of the rotating inner rotor 44, increasing the pressure of the cooling oil passing through the cooling oil outlet 62b. As a result, during operation of the cooling pump 7, as indicated by the arrow in FIG. 4(b), cooling oil under relatively high pressure is supplied from the cooling oil outlet 62b to the gap between the lower surface 60 of the main body 43a of the relative rotation member 43 and the upper surface 44a of the inner rotor 44, forming a stable lubricating oil film in the gap.

[0055] The present invention is not limited to the above-described embodiment, and can be embodied in various forms. For example, in the embodiment, the recess 61 and the cooling oil reservoir 62 are provided on the lower surface 60 of the main body 43a of the relative rotation member 43, but instead, recesses similar to the recess 61 and the cooling oil reservoir 62 can be provided on the upper surface 44a of the inner rotor 44.

[0056] Furthermore, by setting the amount of cooling oil stored in the cooling oil reservoir 25 inside the housing 8 so that the liquid level is always positioned at approximately the same height as the underside 60 of the main body 43a of the relative rotating member 43, it is possible to always form a lubricating oil film in the gap between the upper surface 44a of the inner rotor 44 and the underside 60 of the main body 43a of the relative rotating member 43, and in the gap between the underside 44b of the inner rotor 44 and the upper surface 24c of the bottom wall 24 of the outer rotor holding portion 23.

[0057] However, as described above, by providing the recess 61 or cooling oil reservoir 62 as a refrigerant reservoir of the present invention on the underside 60 of the main body 43a of the relative rotating member 43, a lubricating oil film is formed in the gap between the underside 60 and the upper surface 44a of the inner rotor 44. Therefore, by making the liquid level of the cooling oil to be stored in the cooling oil reservoir 25 lower than the underside 60 of the main body 43a of the relative rotating member 43 and positioning it at approximately the same height as the underside 44b of the inner rotor 44, it is possible to constantly form a lubricating oil film in the gap between the underside 44b of the inner rotor 44 and the upper surface 24c of the bottom wall 24 of the outer rotor holding portion 23, while reducing the amount of cooling oil to be stored in the cooling oil reservoir 25. This reduction in the amount of cooling oil allows for further weight reduction of the motor 1.

[0058] Furthermore, the shape and number of the recesses 61 and cooling oil reservoirs 62 provided on the underside 60 of the main body 43a of the relative rotating member 43 in the motor 1 shown in the embodiment are not particularly limited, and various shapes and numbers of the recesses 61 and cooling oil reservoirs 62 can be adopted as long as a lubricating oil film can be formed by cooling oil in the gap between the underside 60 of the main body 43a and the upper surface 44a of the inner rotor 44 when the cooling pump 7 is operating.

[0059] Furthermore, the detailed configurations of the motor 1, shaft 3, upper rotor 4, lower rotor 5, stator 6, cooling pump 7, and relative rotation member 43 shown in the embodiment are merely examples and can be modified as appropriate within the spirit and scope of the present invention. [Explanation of symbols]

[0060] 1. Motor (rotating machine) 2 rotor blades 3 Shaft (rotating axis) 4 Upper rotor 5 Lower rotor 6 Stator 6a stator core 6b coil 7 Cooling Pump 8. Housing 23 Outer rotor holding part 24 Bottom wall of outer rotor holding section 24a Inlet 24c Upper surface of the bottom wall of the outer rotor holding part 25 Cooling oil reservoir 27 1st cooling oil pipe (refrigerant pipe) 28 2nd cooling oil pipe (refrigerant pipe) 41 Hole in shaft 42 outer rotor part 43 Relative Rotating Member 43a Main body 43b Eccentric protrusion 43c Guide channel (first guide channel) 44 Inner rotor 44a Upper surface (side surface) of inner rotor 44b Underside (side) of inner rotor 47 Cooling oil temporary storage section 48 Guide channel (second guide channel) 60 Lower surface (end surface) of the main body of the relative rotation member 61 Recess (refrigerant reservoir) 62 Cooling oil reservoir (refrigerant reservoir) 62a Reservoir body 62b Cooling oil outflow section (refrigerant outflow section) V Vertical axis (predetermined axis) E Eccentric axis

Claims

1. A cooling structure for a rotating machine that cools a rotating machine having a rotating shaft centered on a predetermined axis and extending along the axis during operation, a cooling pump disposed on the axis within a housing of the rotating machine, the cooling pump rotating integrally with the rotating shaft to operate and circulate a refrigerant for cooling the rotating machine, The rotating shaft is configured to have a hole therein that extends a predetermined length along the axis, has a predetermined diameter, and opens toward the inside of the housing, a relative rotation member that is rotatable relative to the rotation shaft about the axis is provided in the hole, and the relative rotation member has a main body portion formed in a cylindrical shape and extending along the axis, and an eccentric protrusion portion that protrudes from an end face of the main body portion toward the opening side of the hole and extends about an eccentric axis that is radially shifted from the axis, The cooling pump an outer rotor portion having a plurality of teeth along an inner circumferential surface of the opening in the rotary shaft; an inner rotor that is rotatably supported by the eccentric protrusion, has an outer periphery that meshes with the outer rotor portion, and has a side that faces the end face of the main body portion in close proximity to the end face; It has A cooling structure for a rotating machine, characterized in that a refrigerant reservoir is provided on the end face of the main body of the relative rotating member and one of the side faces of the inner rotor to retain the refrigerant and form a lubricating oil film between the end face and the side face.

2. 2. The cooling structure for a rotating machine according to claim 1, wherein the refrigerant reservoir is provided on the end surface of the main body and is formed in a recessed shape that opens toward the side surface of the inner rotor.

3. 3. The cooling structure for a rotating machine according to claim 2, wherein the coolant reservoir portion is composed of a plurality of recesses arranged at intervals from one another, each having a predetermined diameter and depth.

4. The refrigerant reservoir portion is a reservoir body that stores most of the refrigerant to be held in the refrigerant reservoir; a refrigerant outlet portion that is connected to the reservoir body, protrudes in the direction in which the inner rotor rotates, and is formed narrower than the reservoir body; 3. The cooling structure for a rotating machine according to claim 2, further comprising:

5. The rotating machine includes: a rotor that can rotate integrally with the rotary shaft in a state where the rotary shaft passes through the rotor; a stator disposed radially outward of the rotary shaft at a predetermined distance from the rotor in the axial direction; and 5. The cooling structure of a rotating machine according to claim 1, further comprising a refrigerant pipe exposed to the outside from the housing, through which the refrigerant flows when circulating between the cooling pump and the stator.

6. the main body of the relative rotation member has a first guide flow path that guides the coolant discharged from the cooling pump into the interior of the rotation shaft, 6. The cooling structure of a rotating machine according to claim 5, wherein the rotating shaft has a second guide passage extending radially therethrough and communicating the inside and outside of the rotating shaft, and which guides the refrigerant guided into the rotating shaft to the stator.

Images