Rotating Electrical Machine System

Abstract

This invention provides a rotating electric machine system that can operate efficiently by maintaining a constant supply pressure of lubricating oil to the bearing section, even when the ambient pressure changes, thereby ensuring a stable supply of lubricating oil. [Solution] The rotating electric machine system 32 includes a discharge line 66 for discharging gas introduced into the storage section 63 via the bearing section 42 from the storage section 63, a gas-liquid separator 67 provided in the discharge line 66 for separating lubricating oil LO from the gas, and a discharge valve 68 provided downstream of the gas-liquid separator 67 in the discharge line 66 for discharging the gas to the outside of the rotating electric machine system 32. The discharge valve 68 has a pressure-maintaining member 75 that can maintain the internal pressure of the storage section 63 at a target pressure.

Description

Technical Field

[0001] The present disclosure relates to a rotating electrical machine system.

Background Art

[0002] Japanese Patent Laid-Open No. 2022-157657 discloses a configuration in which pressurized fluid (compressed air) generated by an internal combustion engine is introduced into a rotating electrical machine system to form an air curtain, in order to prevent lubricating oil from entering a non-lubricated zone.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0004] However, in a rotating electrical machine system, if the surrounding atmospheric pressure changes depending on the operating state or usage environment, the pressure in the lubricating oil circuit fluctuates, and locations that experience pulsation or negative pressure may occur. Varying the rotational speed of the internal combustion engine to address this phenomenon is not efficient. In addition, increasing the size of auxiliary equipment such as a pump to cope with pressure fluctuations leads to an increase in weight.

[0005] The present disclosure aims to solve the above-described problems.

Means for Solving the Problem

[0006] Aspects of the present disclosure are rotating electric machine systems comprising: a rotating electric machine including a rotor and a stator; a bearing section that rotatably supports the rotor and to which gas is supplied; a supply line for supplying lubricating oil to the bearing section; a supply pump provided on the supply line for delivering the lubricating oil; a recovery line for recovering the lubricating oil that has passed through the bearing section; and a storage section for storing the lubricating oil recovered via the recovery line, wherein the system further comprises: a discharge line for discharging the gas introduced into the storage section via the bearing section from the storage section; a gas-liquid separator provided on the discharge line for separating the lubricating oil from the gas; and a discharge valve provided downstream of the gas-liquid separator in the discharge line for discharging the gas to the outside of the rotating electric machine system, the discharge valve having a pressure-maintaining member capable of maintaining the internal pressure of the storage section at a target pressure. [Effects of the Invention]

[0007] According to the rotating electric machine system of this disclosure, the discharge valve can maintain a predetermined pressurized state in the storage section, so that the supply pressure of lubricating oil can be kept constant even when the ambient pressure of the rotating electric machine system changes. This allows for a stable supply of lubricating oil to the bearing section and enables efficient operation of the rotating electric machine system. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is an external perspective view of the aircraft. [Figure 2] Figure 2 is a schematic diagram of a rotating electric machine system. [Figure 3] Figure 3 is a cross-sectional view of the discharge valve. [Figure 4] Figure 4 is a partially enlarged cross-sectional view of the discharge valve. [Figure 5] Figure 5 shows the relationship between the state of the aircraft and the operation of the exhaust valve. [Figure 6] Figure 6 is a cross-sectional view of a modified discharge valve. [Figure 7] Figure 7 is a schematic diagram of a modified rotating electric machine system. [Modes for carrying out the invention]

[0009] The aircraft 1 shown in Figure 1 is a vertical take-off and landing (VTOL) aircraft. Although the aircraft 1 shown in Figure 1 is a passenger aircraft, the aircraft 1 may also be an unmanned aerial vehicle such as a drone. In this disclosure, the direction in which the aircraft 1 is flying when cruising is defined as "forward," and the opposite direction of "forward" is defined as "rear."

[0010] The aircraft 1 is, for example, an electric vertical take-off and landing aircraft (a so-called eVTOL aircraft). The aircraft 1 comprises a fuselage 12, a forewing wing 14, a rear wing 16, two booms 18, eight VTOL rotors 20, and two cruise rotors 22.

[0011] The front wing 14 is connected to the front of the fuselage 12. The rear wing 16 is connected to the rear of the fuselage 12. The front wing 14 and the rear wing 16 generate lift as the aircraft 1 moves forward.

[0012] The two booms 18 extend in the front-to-back direction. One of the two booms 18 is the right boom 18R, located to the right of the fuselage 12. The other of the two booms 18 is the left boom 18L, located to the left of the fuselage 12.

[0013] The right boom 18R has four VTOL rotors 20 arranged sequentially towards the rear. Similarly, the left boom 18L has four VTOL rotors 20 arranged sequentially towards the rear. Each VTOL rotor 20 is a propeller device that generates vertical upward thrust (lift). Each VTOL rotor 20 is used during the takeoff stroke, vertical climb stroke, transition stroke from climb stroke to cruise stroke, transition stroke from cruise stroke to descent stroke, vertical descent stroke, landing stroke, and stationary flight stroke.

[0014] The VTOL rotor 20 comprises a propeller 24 and a motor 26. The propeller 24 has a plurality of blades 25 arranged at equal intervals in the circumferential direction. The motor 26 is a rotational drive source for rotating the propeller 24. The motor 26 is powered by electricity.

[0015] The rear wing 16 is equipped with two cruise rotors 22, arranged side by side. Each cruise rotor 22 is used during the cruising stroke, the transition stroke from the climbing stroke to cruising stroke, and the transition stroke from cruising to descent stroke. Each cruise rotor 22 is a thrust generator that directs air from front to back, generating thrust to cause the aircraft 1 to fly in a nearly horizontal direction.

[0016] The aircraft 1 further comprises a combined power system 30. The combined power system 30 is located, for example, at the rear of the fuselage 12. Multiple combined power systems 30 may be provided. The combined power system 30 is a power generation system that generates electricity to supply power to the VTOL rotor 20 and the cruise rotor 22. The combined power system 30 comprises a rotating electric machine system 32 and an internal combustion engine 34. The rotating electric machine system 32 and the internal combustion engine 34 are arranged in series on the same axis. The internal combustion engine 34 may be, for example, a gas turbine engine 34A. In place of the gas turbine engine 34A, other forms of internal combustion engine 34 (such as a reciprocating engine) may be used.

[0017] As shown in Figure 2, the rotating electric machine system 32 comprises a rotating electric machine 35 and a rotating electric machine housing 36. In this embodiment, the rotating electric machine 35 is a generator. The rotating electric machine 35 comprises a rotor 35a and a stator 35b. The rotor 35a has permanent magnets (not shown). Inside the rotating electric machine housing 36 is a bearing section 42 including a first bearing 38 and a second bearing 40. The rotor 35a is rotatably supported relative to the rotating electric machine housing 36 via the first bearing 38 and the second bearing 40.

[0018] The bearing portion 42 has a first bearing portion 42A and a second bearing portion 42B. The first bearing portion 42A has a first bearing 38 and a first bearing chamber 39. The second bearing portion 42B has a second bearing 40 and a second bearing chamber 41. The first bearing 38 and the second bearing 40 are arranged at intervals in the axial direction of the rotor 35a. The first bearing chamber 39 accommodates the first bearing 38. The second bearing chamber 41 accommodates the second bearing 40.

[0019] The rotating electrical machine system 32 is provided with a sealing gas flow path structure 44, a lubricating oil flow path structure 45, and an oil circulation supply device 46.

[0020] The sealing gas flow path structure 44 supplies sealing gas toward the first bearing 38 and the second bearing 40. The gas is supplied from a gas supply device 47. In the following description, air is illustrated as an example of the gas.

[0021] The sealing gas flow path structure 44 includes a gas supply path 48, a first branch path 49, and a second branch path 50. An air supply port serving as an inlet to the gas supply path 48 is provided on the outer surface of the rotating electrical machine housing 36. The gas supply path 48 is formed in the rotating electrical machine housing 36. The first branch path 49 and the second branch path 50 are part of an accommodation chamber 51 that accommodates the rotor 35a and the stator 35b.

[0022] The air that has passed through the gas supply path 48 flows into the accommodation chamber 51. The air that has flowed into the accommodation chamber 51 is split by the first branch path 49 and the second branch path 50.

[0023] The first branch path 49 is a flow path that directs air toward the first bearing 38. The air that has passed through the first branch path 49 flows toward the first bearing 38 and flows into the first bearing chamber 39. The air flowing toward the first bearing 38 forms an air curtain for preventing the lubricating oil LO from entering the accommodation chamber 51.

[0024] The second branch passage 50 is a clearance between the rotor 35a and the stator 35b that extends along the axial direction of the rotor 35a. The second branch passage 50 is a passage that directs air toward the second bearing 40. The air that has passed through the second branch passage 50 flows toward the second bearing 40 and enters the second bearing chamber 41. The air flowing toward the second bearing 40 forms an air curtain to prevent lubricating oil LO from entering the containment chamber 51.

[0025] The lubrication oil flow path structure 45 is a flow path for supplying lubricating oil LO to the first bearing 38 and the second bearing 40. The lubrication oil flow path structure 45 includes a lubrication oil inlet passage 54, a first branch passage 55a, and a second branch passage 55b. The lubrication oil inlet passage 54, the first branch passage 55a, and the second branch passage 55b constitute an oil supply passage 56 provided in the rotating electric machine housing 36. Lubricating oil LO is supplied from the oil circulation supply device 46 to the lubrication oil inlet passage 54.

[0026] The lubricating oil introduction passage 54 branches into a first branch passage 55a and a second branch passage 55b inside the rotating electric machine housing 36. The lubricating oil LO is supplied to the first bearing 38 via the first branch passage 55a. The lubricating oil LO supplied to the first bearing 38 is discharged from the first bearing chamber 39 via the first discharge port 56a. As described above, an air curtain is formed near the first bearing 38. Therefore, the entry of the lubricating oil LO supplied to the first bearing 38 into the containment chamber 51 is suppressed.

[0027] Lubricating oil LO is supplied to the second bearing 40 via the second branch passage 55b. The lubricating oil LO supplied to the second bearing 40 is discharged from the second bearing chamber 41 via the second outlet 56b. As described above, an air curtain is formed near the second bearing 40. Therefore, the entry of lubricating oil LO supplied to the second bearing 40 into the containment chamber 51 is suppressed.

[0028] The oil circulation supply device 46 supplies lubricating oil LO to the oil supply passage 56 of the rotating electric machine housing 36, recovers lubricating oil LO from the rotating electric machine housing 36, and performs an oil circulation operation in which it supplies lubricating oil LO back to the oil supply passage 56. The oil circulation supply device 46 comprises a supply line 58, a supply pump 59, a recovery line 60, a recovery pump 62, and a storage section 63.

[0029] The supply line 58 is an oil path that supplies lubricating oil LO to the bearing section 42. The supply pump 59 is located on the supply line 58 and pumps the lubricating oil LO. Specifically, the supply pump 59 draws lubricating oil LO from the storage section 63 and supplies the lubricating oil LO to the oil supply passage 56 of the rotating electric machine housing 36 via the supply line 58.

[0030] The recovery line 60 is an oil path that recovers lubricating oil LO that has passed through the bearing section 42 to the storage section 63. The recovery pump 62 is provided in the recovery line 60. The recovery pump 62 guides the lubricating oil LO to the storage section 63 via the recovery line 60. When the recovery pump 62 is driven, lubricating oil LO is sucked from the first bearing chamber 39 and the second bearing chamber 41 via the first drain passage 64a and the second drain passage 64b. The sucked lubricating oil LO flows into the storage section 63 via the recovery line 60.

[0031] The storage section 63 is a tank for storing lubricating oil LO discharged (recovered) from the first bearing chamber 39 and the second bearing chamber 41. Air discharged from the first bearing chamber 39 and the second bearing chamber 41, respectively, is introduced into the storage section 63 via the first gas outlet line 52a and the second gas outlet line 52b. The air discharged from the first bearing chamber 39 and the second bearing chamber 41 is a gas-liquid mixed fluid containing mist-like lubricating oil LO.

[0032] The storage section 63 has a gas-liquid separation function that separates lubricating oil LO from the gas-liquid mixed fluid flowing in through the first gas outlet line 52a and the second gas outlet line 52b. Specifically, the storage section 63 has a gas-liquid separation section 65. The gas-liquid separation section 65 has, for example, a gas-liquid separation promoting member 65A. The gas-liquid separation promoting member 65A is a porous structure. The gas-liquid mixed fluid flowing into the gas-liquid separation promoting member 65A comes into contact with the non-space portion of the gas-liquid separation promoting member 65A, thereby promoting gas-liquid separation. As a result, the gas-liquid mixed fluid flowing into the storage section 63 undergoes gas-liquid separation in the storage section 63.

[0033] A discharge line 66 is connected to the storage section 63. The discharge line 66 is a path for discharging mainly gas, which has undergone gas-liquid separation from the gas-liquid mixed fluid in the storage section 63. A gas-liquid separator 67 is provided in the discharge line 66. Air containing some lubricating oil LO is discharged from the storage section 63 and introduced into the gas-liquid separator 67. The gas-liquid separator 67 separates the lubricating oil LO from the air containing some lubricating oil LO. A discharge valve 68 is provided downstream of the gas-liquid separator 67 in the discharge line 66. The discharge valve 68 discharges the air from which the lubricating oil LO has been separated to the outside of the rotating electric machine system 32. The discharge valve 68 can maintain the internal pressure of the storage section 63 at a preset target pressure. Details of the discharge valve 68 will be described later.

[0034] The air, further separated into gas and liquid form in the gas-liquid separator 67, is released into the atmosphere via the discharge valve 68. If lubricating oil LO is separated in the gas-liquid separator 67, the separated lubricating oil LO is returned to the storage unit 63 via the return line 69. Alternatively, the lubricating oil LO separated in the gas-liquid separator 67 may be returned to the recovery line 60.

[0035] As shown in Figure 3, the discharge valve 68 comprises a valve housing 70, a cylinder 72, a valve body 74, a spring member 76, a spring receiving portion 77, a holder 78, and an adjustment member 79.

[0036] The valve housing 70 is connected to piping 81a which constitutes the discharge line 66, piping 81b which constitutes the open-to-atmosphere line 80, and piping 81c which constitutes the bypass line 82. The valve housing 70 has a first discharge path 83a and a second discharge path 83b. The first discharge path 83a is a path that is open to the atmosphere. The first discharge path 83a communicates with the discharge line 66 and the open-to-atmosphere line 80. The second discharge path 83b communicates with the discharge line 66, the first discharge path 83a, and the bypass line 82. The second discharge path 83b has an annular space 83s that surrounds the cylinder 72.

[0037] As shown in Figure 4, the cylinder 72 is hermetically fixed to the valve housing 70. The cylinder 72 is constructed in a hollow cylindrical shape. The cylinder 72 may be cylindrical in shape. The cylinder 72 has a circumferential wall portion 720, a cavity portion 721, an inlet portion 722, a seat portion 723, and an outlet portion 724. The circumferential wall portion 720 extends in the axial direction (X direction) of the cylinder 72. The circumferential wall portion 720 surrounds the cavity portion 721. The circumferential wall portion 720 is located within the second discharge path 83b.

[0038] The inlet 722 is provided at one end of the peripheral wall portion 720. The inlet 722 communicates with the cavity portion 721. The inlet 722 penetrates one end of the cylinder 72 in the axial direction. The seat portion 723 surrounds the inlet 722 in the cavity portion 721. The seat portion 723 is a stepped surface between the inner circumferential surface surrounding the inlet 722 and the inner circumferential surface surrounding the cavity portion 721 in the cylinder 72.

[0039] The outlet 724 may communicate with the inlet 722 via the cavity 721. The outlet 724 penetrates the circumferential wall 720 in the radial direction of the cylinder 72. The outlet 724 is provided at a position axially spaced away from the seat 723. Multiple outlets 724 are provided at intervals in the circumferential direction of the cylinder 72. Only one outlet 724 may be provided.

[0040] The valve body 74 is located in the second discharge path 83b. The valve body 74 is a pressure-maintaining member 75 that can operate to maintain the pressure in the reservoir 63 (Figure 2) at a target pressure. As shown in Figure 4, the valve body 74 is displaceable in the axial direction (X direction) of the cylinder 72 within the cavity 721. The valve body 74 may be hollow. The head 740 of the valve body 74 is provided with a seating surface 741 facing the seating portion 723. In the closed valve state shown in Figure 4, the seating surface 741 abuts against the seating portion 723. The valve body 74 is displaceable in the axial direction between the seating portion 723 of the cylinder 72 and one end face of the holder 78. That is, the closed-side stroke end of the valve body 74 is defined by the seating portion 723. The open-side stroke end of the valve body 74 is defined by one end face of the holder 78.

[0041] The head 740 of the valve body 74 has a projection 742 that extends along the circumferential direction of the valve body 74. The projection 742 protrudes toward the seat portion 723. A seating surface 741 is formed on the tip surface of the projection 742. The projection 742 is provided with a plurality of notched connecting passages 743 spaced apart in the circumferential direction of the valve body 74.

[0042] A clearance CL is formed between the inner surface of the peripheral wall portion 720 and the outer surface of the valve body 74, allowing gas flow. The clearance CL is a minute gap formed by the difference between the inner diameter of the peripheral wall portion 720 (the diameter of the cavity portion 721) and the outer diameter of the valve body 74. In the valve seated state, where the seat surface 741 of the valve body 74 abuts against the receiving portion 723, the inlet 722 and the outlet 724 communicate via the clearance CL.

[0043] The spring member 76 biases the valve body 74 toward the seat portion 723 of the cylinder 72. The spring member 76 extends along the axial direction of the cylinder 72. The spring member 76 may be a coil spring. One end of the spring member 76 can be inserted into the valve body 74.

[0044] As shown in Figure 3, the spring support portion 77 supports the other end of the spring member 76. The spring support portion 77 is located within a hollow holder 78. The spring support portion 77 is axially displaceable within the holder 78. The spring support portion 77 is liquid-tightly slidable against the inner circumferential surface of the holder 78. The holder 78 is hermetically fixed to the cylinder 72. The holder 78 accommodates a portion of the spring member 76.

[0045] The adjustment member 79 adjusts the length (spring length) of the spring member 76 within the cylinder 72 and the holder 78. By adjusting the spring length, the opening pressure of the discharge valve 68 can be adjusted. The adjustment member 79 is inserted into the holder 78. One end of the adjustment member 79 abuts against the spring receiving portion 77. The adjustment member 79 may be a bolt. Alternatively, the length of the spring member 76 may be adjusted by setting the thickness (length) of the spring receiving portion 77 without providing the adjustment member 79. In addition, the length (space) of the spring member 76 can also be adjusted by setting the length of either the cylinder 72 or the holder 78, or both.

[0046] The discharge valve 68 configured as described above operates as follows:

[0047] When the pressure of the fluid flowing through the discharge line 66 is below the set value (target pressure), the discharge valve 68 remains closed. That is, as shown in Figure 4, the valve body 74 is in a seated state with its seat surface 741 in contact with the receiving portion 723. In the seated state, the inner (first surface 740a) and outer (second surface 740b) surfaces of the protrusion 742 on the head 740 of the valve body 74 are in communication with each other via the communication passage 743. Therefore, in the seated state, pressure acts not only on the first surface 740a but also on the second surface 740b.

[0048] Furthermore, in the seated state, a clearance CL is formed between the inner surface of the circumferential wall portion 720 and the outer surface of the valve body 74. Therefore, the fluid that reaches the second surface 740b flows through the clearance CL and flows out from the outlet 724. In other words, in the seated state, the space between the cylinder 72 and the valve body 74 is not airtight, and a small amount of fluid leaks from the outlet 724 through the minute clearance CL. In this case, the region where the area between the seat portion 723 and the outlet 724 on the inner surface of the circumferential wall portion 720 overlaps with the outer surface of the valve body 74 is the liquid leak passage LP. The length of the leak passage LP along the axial direction is maximum in the seated state. Therefore, in the seated state, the fluid resistance due to the leak passage LP is maximum, and the amount of leakage is minimum.

[0049] When the pressure of the fluid flowing through the discharge line 66 reaches a set value, the valve body 74 begins to displace axially (in the X1 direction). This set value is the cracking pressure at which the discharge valve 68 opens. As the valve body 74 begins to displace, the seating surface 741 of the valve body 74 separates from the seating portion 723. With this separation, the seating surface 741 becomes a pressure-receiving surface in addition to the first surface 740a and the second surface 740b. Therefore, the area of ​​the seating surface 741 before and after the separation of the seating surface 741 of the valve body 74 from the seating portion 723 represents the difference in the pressure-receiving area. When the valve body 74 displaces axially, the fluid is discharged from the space inside the cylinder 72 into the annular space 83s through the hole 748 provided in the cylinder 72. For this reason, the displacement of the valve body 74 is not hindered.

[0050] As the pressure of the fluid flowing through the discharge line 66 increases, the valve body 74 begins to displace. The displacement of the valve body 74 increases the pressure-receiving surface, which consists of the first surface 740a, the second surface 740b, and the seating surface 741. As a result, the pressure that tries to push the valve body 74 back to the seating surface (the value obtained by dividing the load of the spring member 76 by the pressure-receiving area) decreases. This increases the amount of displacement of the valve body 74. As the amount of displacement of the valve body 74 increases, the load of the spring member 76 increases, and the pressure increases in the direction that pushes the valve body 74 toward the pressure-receiving surface. The valve body 74 moves to an equilibrium position where this upward pressure and the pressure of the liquid flowing through the discharge line 66 are balanced. This makes it possible to maintain the pressure of the fluid flowing through the discharge line 66 (the pressure in the storage section 63 shown in Figure 2) at the target pressure.

[0051] The combined power system 30 shown in Figure 2 operates as follows:

[0052] First, the gas turbine engine 34A is started by the drive of the rotating electric machine 35. Once the gas turbine engine 34A is started, the rotor 35a of the rotating electric machine 35 rotates due to the rotational driving force of the output shaft 168 of the gas turbine engine 34A, and the rotating electric machine 35 generates electricity. As a result, the combined power system 30 becomes operational.

[0053] During operation of the combined power system 30, air is supplied to the rotating electric machine housing 36 from the gas supply device 47 (in this embodiment, the gas turbine engine 34A), and can be sealed by an air curtain as described above. In addition, lubricating oil LO is supplied from the oil circulation supply device 46 to the oil supply passage 56 of the rotating electric machine housing 36, and lubricating oil LO is supplied to the first bearing 38 and the second bearing 40.

[0054] Lubricating oil LO is drawn in at the first outlet 56a and discharged from the first bearing chamber 39. Lubricating oil LO that has lubricated the second bearing 40 in the second bearing chamber 41 is drawn in at the second outlet 56b and discharged from the second bearing chamber 41.

[0055] On the other hand, air is discharged from the first bearing chamber 39 via the first gas outlet line 52a. In this way, the fluid in the first bearing chamber 39 is separated to some extent into lubricating oil LO and air, and is discharged from the first bearing chamber 39 as a gas-liquid mixed fluid with a large air component. Also, air is discharged from the second bearing chamber 41 via the second gas outlet line 52b. In this way, the fluid in the second bearing chamber 41 is separated to some extent into lubricating oil LO and air, and is discharged from the second bearing chamber 41 as a gas-liquid mixed fluid with a large air component. In other words, the first bearing chamber 39 and the second bearing chamber 41 function as a first gas-liquid separation unit.

[0056] In the storage section 63, air (gas-liquid mixed fluid) containing lubricating oil LO discharged from the first bearing chamber 39 and the second bearing chamber 41 is introduced via the first gas outlet line 52a and the second gas outlet line 52b, respectively, and gas-liquid separation is performed again. Therefore, the storage section 63 functions as a second gas-liquid separation section.

[0057] The air separated in the storage section 63 is discharged from the storage section 63. The air discharged from the storage section 63, which contains some lubricating oil LO, is subjected to further gas-liquid separation by the gas-liquid separator 67. Therefore, the gas-liquid separator 67 functions as a third gas-liquid separation section. The air that has passed through the gas-liquid separator 67 is released into the atmosphere via the discharge valve 68.

[0058] Next, referring to Figure 5, the operation of the discharge valve 68 (Figure 2, etc.) will be explained in relation to the state of the aircraft 1. In the following, we will mainly refer to Figure 5, but we will also mention the components shown in Figures 2 to 4. Here, we assume that the aircraft 1's composite power system 30 is started on the ground and operates at its rated speed, then takes off, climbs to cruising altitude (maximum altitude), cruises at that altitude, descends, and lands.

[0059] In the following, standard atmospheric pressure (approximately 101.3 kPa) will be referred to as "first atmospheric pressure." First atmospheric pressure is the maximum pressure in the environment in which the combined power system 30 is used. Furthermore, the atmospheric pressure at the highest altitude of the aircraft 1 will be referred to as "second atmospheric pressure." Second atmospheric pressure is the minimum pressure in the environment in which the combined power system 30 is used.

[0060] When the aircraft 1 is on standby on the ground and the combined power system 30 is stopped, the atmospheric pressure around the combined power system 30 is standard atmospheric pressure. The combined power system 30 is started while the aircraft 1 is stopped on the ground. As shown in Figure 5, after the gas turbine engine 34A is started, the flow rate of air supplied to the rotating electric machine system 32 (rotating electric machine housing 36) (hereinafter referred to as "air supply amount") increases as the engine speed increases (Graph A). The gas turbine engine 34A increases its rotational speed to the rated operating speed Nr and then maintains rated operation thereafter. At this point, the opening diameter of the atmospheric release line 80 of the discharge valve 68 is narrowed more than usual so that the pressure inside the storage section 63 increases relative to the surrounding atmospheric pressure.

[0061] As the air flow rate increases, the pressure inside the storage section 63 (and gas-liquid separator 67) (hereinafter referred to as "tank pressure") also increases due to the throttling of the atmospheric release line 80 (Graph B). In this embodiment, equipped with a discharge valve 68, at standard atmospheric pressure (first atmosphere), when the air supply pressure reaches a predetermined pressure (reaches the cracking pressure), the valve body 74 moves, causing the discharge valve 68 (valve body 74) to open (to its maximum opening) (Graphs B and C show it fully open). As a result, the tank pressure becomes constant at the target pressure (Graph B). The target pressure is, for example, matched to the atmospheric pressure at the altitude in which the aircraft operates. Specifically, it can be set to match the pressure decrease due to altitude (first atmosphere - second atmosphere). Therefore, the tank pressure is maintained at a predetermined pressurized state. On the other hand, if the discharge valve 68 is not provided and the gas-liquid separator is directly released to the atmosphere, it is necessary to increase the air supply amount to prevent the tank pressure from decreasing due to the drop in atmospheric pressure.

[0062] As shown in Graph E, as the aircraft 1 takes off and its altitude increases, the opening of the exhaust valve 68 decreases as the surrounding atmospheric pressure decreases. When the aircraft 1 reaches its cruising altitude (maximum altitude), the exhaust valve 68 is at its smallest opening (shown as fully closed in Graph E). The opening of the exhaust valve 68 decreases as it moves from standard atmospheric pressure (first pressure) to atmospheric pressure at cruising altitude (second pressure). Therefore, as shown in Graph D, the tank pressure is maintained at the target pressure even as the altitude of the aircraft 1 increases. While the aircraft 1 is cruising at its maximum altitude, the exhaust valve 68 maintains its minimum opening, and the tank pressure is also maintained at a constant target pressure.

[0063] Subsequently, as the aircraft descends in preparation for landing, the opening of the discharge valve 68 increases as the surrounding atmospheric pressure increases. As a result, as shown in graph D, the tank pressure is maintained at the target pressure even as the aircraft 1's altitude decreases. When the aircraft 1 lands, the surrounding atmospheric pressure becomes standard atmospheric pressure (first atmosphere), and the discharge valve 68 opens to its maximum extent again (shown as fully open in graph E). Since the discharge valve 68 remains fully open after landing (graph E), the tank pressure is maintained at the target pressure (graph D).

[0064] On the other hand, unlike this embodiment, if the discharge valve 68 is not provided in graph D, the tank pressure will fluctuate with the change in altitude of the aircraft 1. As the altitude of the aircraft 1 increases, the tank pressure decreases, and when the aircraft 1 is at its highest altitude, the tank pressure is at its lowest value. For this reason, if the discharge valve 68 is not provided, the tank pressure may become negative.

[0065] This embodiment provides the following effects.

[0066] As shown in Figure 2, the rotating electric machine system 32 is equipped with a discharge valve 68 located downstream of the gas-liquid separator 67 in the discharge line 66 to discharge gas to the outside of the rotating electric machine system 32. The discharge valve 68 has a pressure-maintaining member 75 that can maintain the internal pressure of the storage section 63 at a target pressure. With this configuration, the discharge valve 68 can maintain the storage section 63 under a predetermined pressurized state, so even if the ambient pressure around the rotating electric machine system 32 changes, the supply pressure of lubricating oil LO, the air pressure, and the air supply amount can be kept constant. This allows for a stable supply of lubricating oil LO to the bearing section 42, enabling efficient operation of the rotating electric machine system 32. Since the rotating electric machine system 32 and the gas turbine engine 34A can be operated continuously at the rated rotational speed, the operating efficiency can be increased.

[0067] Furthermore, since the lubrication oil circuit, including the supply line 58 and the discharge line 66, can be prevented from becoming negatively pressurized, cavitation of the lubricating oil LO in the circuit and malfunctions of the supply pump 59 can be prevented, thereby improving the durability of the rotating electric machine system 32.

[0068] As shown in Figure 3, the discharge valve 68 has a valve housing 70 into which air is introduced. The pressure maintaining member 75 is a valve body 74 positioned inside the valve housing 70 so as to be operable to maintain a target pressure. With this configuration, the target pressure can be effectively maintained by the operation of the valve body 74.

[0069] The valve body 74 is configured to open when the target pressure is reached, by setting a restriction on the line that opens to the atmosphere so that the pressure in the reservoir 63 (Figure 2) rises when the rotating electric machine system 32 is started. With this configuration, the target pressure can be reached at an early stage during startup.

[0070] The discharge valve 68 has a first discharge path 83a that is open to the atmosphere and a second discharge path 83b that communicates with the first discharge path 83a. The valve body 74 is located in the second discharge path 83b. With this configuration, the target pressure can be effectively maintained by the operation of the valve body 74.

[0071] In the rated operating state of the rotating electric machine system 32 shown in Figure 2, the valve body 74 opens to its maximum degree when the atmospheric pressure around the rotating electric machine system 32 is at 1 atmosphere, and opens to its minimum degree when the atmospheric pressure is at 2 atmosphere, which is lower than 1 atmosphere, and the opening decreases from 1 atmosphere to 2 atmosphere (see also Figure 5). With this configuration, even if the atmospheric pressure decreases due to changes in the environment around the rotating electric machine system 32, the pressure in the reservoir 63 can be effectively maintained at the target pressure.

[0072] The rotating electric machine system 32 is equipped with gas outlet lines (first gas outlet line 52a and second gas outlet line 52b) that guide gas that has passed through the bearing section 42 to the storage section 63. With this configuration, gas can be flowed to the storage section 63 via the gas outlet lines, thus reducing the amount of gas in the recovery line 60. The bearing section 42, which is in communication with the storage section 63 via the gas outlet lines, can also be kept under pressure, and the lubrication oil circuit can be kept under pressure, thereby reducing the fluid supply load of lubricating oil LO in the lubrication oil circuit.

[0073] The storage unit 63 has a gas-liquid separation unit 65 that separates the lubricating oil LO from the fluid flowing in through the gas outlet line. With this configuration, since the storage unit 63 itself has a gas-liquid separation function, the load on the gas-liquid separator 67 located downstream can be reduced.

[0074] The recovery line 60 is equipped with a recovery pump 62 for guiding the lubricating oil LO to the storage section 63. With this configuration, the lubricating oil LO can be circulated regardless of the position of the bearing section 42 relative to the storage section 63, so any arrangement is possible. In particular, in the case of an aircraft, the rotating electric machine system 32 can be laid out regardless of the flight state.

[0075] An internal combustion engine 34 is connected to the rotating electric machine system 32, and air is supplied from the internal combustion engine 34 to the rotating electric machine system 32. With this configuration, it is not necessary to increase the rotational speed of the internal combustion engine 34 above its rated speed in order to maintain the pressure in the lubrication oil circuit, thus the internal combustion engine 34 can be operated efficiently.

[0076] In the rotating electric machine system 32, the discharge valve 68A shown in Figure 6 may be used. The discharge valve 68A has a single discharge path 83. The upstream region of the discharge path 83 communicates with the discharge line 66. The downstream region of the discharge path 83 communicates with the atmospheric release line 80. A valve body 74M is positioned in the intermediate region of the discharge path 83. A through hole 746 is formed in the head 740 of the valve body 74M. Therefore, the discharge line 66 and the atmospheric release line 80 are always in communication through the through hole 746. The discharge valve 68A configured in this way is fully open at standard atmospheric pressure (first atmosphere) and fully closed at atmospheric pressure at cruising altitude (second atmosphere) during the rated operation of the rotating electric machine system 32 (Figure 2). Therefore, the discharge valve 68A can be operated to maintain the pressure in the storage section 63 (Figure 2) at the target pressure.

[0077] In the embodiment described above, passively operating discharge valves 68 and 68A (Figures 4 and 6) were used, but as shown in Figure 7, a discharge valve 68B controlled by a control unit 86 may also be used. In this case, the discharge valve 68B is a servo valve whose valve opening degree can be adjusted. The control unit 86 has a calculation unit. The calculation unit is composed of a processor, such as a CPU (Central Processing Unit), i.e., a processing circuitry. The pressure in the storage unit 63 can be detected by a pressure sensor 88. The detection result of the pressure sensor 88 is input to the control unit 86.

[0078] During rated operation of the rotating electric machine system 32 (Figure 2), the control unit 86 controls the discharge valve 68B to maintain the internal pressure of the storage unit 63 at the target pressure. Therefore, the discharge valve 68B controlled by the control unit 86, like the discharge valve 68 shown in Figure 2, can maintain a constant supply pressure of lubricating oil LO even when the ambient pressure around the rotating electric machine system 32 changes.

[0079] The following additional information is disclosed regarding the above embodiments.

[0080] (Note 1) The rotating electric machine system (32) of this disclosure comprises: a rotating electric machine (35) including a rotor (35a) and a stator (35b); a bearing section (42) that rotatably supports the rotor and to which gas is supplied; a supply line (58) that supplies lubricating oil (LO) to the bearing section; a supply pump (59) provided on the supply line for transporting the lubricating oil; a recovery line (60) for recovering the lubricating oil that has passed through the bearing section; and a storage section (63) for storing the lubricating oil recovered via the recovery line. The present invention relates to a rotating electric machine system comprising: a discharge line (66) for discharging the gas introduced into the storage section via the bearing section from the storage section; a gas-liquid separator (67) provided in the discharge line for separating the lubricating oil from the gas; and a discharge valve (68) provided downstream of the gas-liquid separator in the discharge line for discharging the gas to the outside of the rotating electric machine system, wherein the discharge valve has a pressure-maintaining member (75) capable of maintaining the internal pressure of the storage section at a target pressure. With this configuration, the discharge valve can maintain the storage section in a pressurized state at a predetermined pressure, so that the supply pressure of the lubricating oil can be kept constant even when the ambient pressure of the rotating electric machine system changes. This allows for a stable supply of lubricating oil to the bearing section and efficient operation of the rotating electric machine system. Since the lubricating oil circuit, including the supply line and discharge line, can avoid negative pressure, cavitation of the lubricating oil in the circuit and malfunctions of the supply pump can be prevented, thereby improving the durability of the rotating electric machine system.

[0081] (Note 2) In the rotating electric machine system described in Note 1, the discharge valve may have a valve housing (70) into which the gas is introduced, and the pressure maintaining member may be a valve body (74) positioned inside the valve housing so as to be operable to maintain the target pressure. With such a configuration, the target pressure can be effectively maintained by the operation of the valve body.

[0082] (Note 3) In the rotating electric machine system described in Note 2, the valve body may be in the most open state when the pressure in the reservoir rises to the target pressure during startup of the rotating electric machine system. With such a configuration, the system can be operated at its rated capacity at an early stage during startup.

[0083] (Note 4) In the rotating electric machine system described in Note 2, the discharge valve has a first discharge path (83a) open to the atmosphere and a second discharge path (83b) communicating with the first discharge path, and the valve body may be provided in the second discharge path. With this configuration, if the ambient pressure of the rotating electric machine system changes, the gas discharge flow rate is adjusted in the second discharge path. This makes it possible to effectively maintain the internal pressure of the storage section at the target pressure.

[0084] (Note 5) In the rotating electric machine system described in Note 2, during the operation of the rotating electric machine system, the valve body may be at its maximum opening when the atmospheric pressure around the rotating electric machine system is at a first atmosphere, and at its minimum opening when the atmospheric pressure is at a second atmosphere which is less than the first atmosphere, and the opening may decrease from the first atmosphere to the second atmosphere. With such a configuration, even if the atmospheric pressure decreases due to changes in the environment around the rotating electric machine system, the pressure in the reservoir can be effectively maintained at the target pressure.

[0085] (Note 6) In the rotating electric machine system described in any one of Notes 1 to 5, a gas outlet line may be provided to guide the gas that has passed through the bearing section to the storage section. With such a configuration, the gas can be flowed to the storage section via the gas outlet line, thereby reducing the amount of gas in the recovery line. The bearing section that communicates with the storage section via the gas outlet line can also be kept under pressure, and the lubrication oil circuit can be kept under pressure, thereby reducing the fluid supply load of the lubricating oil in the lubrication oil circuit.

[0086] (Note 7) In the rotating electric machine system described in Note 6, the storage unit may have a gas-liquid separation unit (65) that separates the lubricating oil from the fluid flowing in through the gas outlet line. With such a configuration, the storage unit itself has a gas-liquid separation function, which reduces the load on the gas-liquid separator located downstream.

[0087] (Note 8) In the rotating electric machine system described in any one of Notes 1 to 5, the recovery line may be provided with a recovery pump (62) for guiding the lubricating oil to the storage section. With this configuration, the lubricating oil can be circulated regardless of the position of the bearing section relative to the storage section, so any arrangement is possible.

[0088] (Note 9) In the rotating electric machine system described in any one of Notes 1 to 5, an internal combustion engine (34) may be connected to the rotating electric machine system, and the gas may be supplied from the internal combustion engine to the rotating electric machine system. With this configuration, it is not necessary to increase the rotational speed of the internal combustion engine above its rated speed in order to maintain the pressure in the lubrication oil circuit, and the internal combustion engine can be operated efficiently.

[0089] While this disclosure has been described in detail, it is not limited to the individual embodiments described above. These embodiments can be added, replaced, modified, partially deleted, etc., in any way that does not depart from the gist of this disclosure or from the intent of this disclosure derived from the claims and their equivalents. These embodiments can also be implemented in combination. For example, the order of operations and processes in the embodiments described above are given as examples only and are not limited thereto. The same applies when numerical values ​​or mathematical formulas are used in the description of the embodiments described above. [Explanation of Symbols]

[0090] 30…Combined power systems 32…Rotating electric machine systems 34...Internal combustion engine 42...Bearing section 58…Supply line 59…Supply pump 60... Recovery line 62... Recovery pump 63...Storage section 66...Discharge line 67...Gas-liquid separator 68, 68A, 68B...Discharge valves

Claims

1. A rotating electric machine including a rotor and stator, The rotor is rotatably supported by a bearing section to which gas is supplied, A supply line for supplying lubricating oil to the bearing section, A supply pump provided in the supply line for delivering the lubricating oil, A recovery line for recovering the lubricating oil that has passed through the bearing section, A storage section for storing the lubricating oil recovered via the recovery line, A rotating electric machine system equipped with, A discharge line for discharging the gas introduced into the storage section via the bearing section from the storage section, A gas-liquid separator provided in the discharge line for separating the lubricating oil from the gas, The discharge line includes a discharge valve provided downstream of the gas-liquid separator for discharging the gas to the outside of the rotating electric machine system, The discharge valve has a pressure-maintaining member capable of maintaining the internal pressure of the storage section at a target pressure, in a rotating electric machine system.

2. In the rotating electric machine system according to claim 1, The discharge valve has a valve housing into which the gas is introduced, The pressure-maintaining member is a valve body disposed inside the valve housing so as to be operable to maintain the target pressure, in a rotating electric machine system.

3. In the rotating electric machine system according to claim 2, The valve body is in its widest opening position when the pressure in the reservoir rises to the target pressure during startup of the rotating electric machine system.

4. In the rotating electric machine system according to claim 2, The discharge valve has a first discharge path open to the atmosphere and a second discharge path communicating with the first discharge path. The valve body is provided in the second discharge path, and is part of a rotating electric machine system.

5. In the rotating electric machine system according to claim 2, In the operating state of the rotating electric machine system, the valve body has the maximum opening degree when the atmospheric pressure around the rotating electric machine system is at a first atmosphere, and the minimum opening degree when the atmospheric pressure is at a second atmosphere which is less than the first atmosphere, and the opening degree decreases from the first atmosphere to the second atmosphere.

6. In the rotating electric machine system according to any one of claims 1 to 5, A rotating electric machine system comprising a gas outlet line that guides the gas, which has passed through the bearing section, to the storage section.

7. In the rotating electric machine system according to claim 6, The storage unit has a gas-liquid separation unit that separates the lubricating oil from the fluid flowing in through the gas outlet line, in a rotating electric machine system.

8. In the rotating electric machine system according to any one of claims 1 to 5, A rotating electric machine system, wherein the recovery line is provided with a recovery pump for guiding the lubricating oil to the storage section.

9. In the rotating electric machine system according to any one of claims 1 to 5, The aforementioned rotating electric machine system is connected to an internal combustion engine. A rotating electric machine system in which the gas is supplied from the internal combustion engine to the rotating electric machine system.

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