Refrigerant circulation system

Abstract

To share a refrigerant circulation system properly between a motor including a slide bearing which uses a refrigerant as a lubricant and an air conditioner.SOLUTION: A refrigerant circulation system 100 includes: a compressor 5 which compresses a refrigerant containing CO2; a motor 1 including a rotor 11 and a stator 12, a rotary shaft 13 connected to the rotor 11, and a slide bearing 14 supporting the rotary shaft 13, the motor 1 being configured so as to be supplied with the refrigerant compressed by the compressor 5 to allow the slide bearing 14 to be lubricated with the refrigerant serving as a lubricant; an air conditioner 2 which performs air conditioning by using the refrigerant compressed by the compressor 5; and a switching mechanism 7 which may switch a state of the system between a first state where the refrigerant is supplied only to the motor 1 and a second state in which the refrigerant is supplied to both of the motor 1 and the air conditioner 2.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a refrigerant circulation system that circulates a refrigerant. [Background technology]

[0002] Conventionally, refrigerant circulation systems that circulate refrigerant through compressors, heat exchangers, etc. have been used in refrigeration cycles used in air conditioners. In recent years, such refrigerant circulation systems have also been used to cool the batteries of electric vehicles and hybrid vehicles. For example, Patent Document 1 discloses a technology that aims to make the system smaller and less expensive by sharing a single compressor and supplying the refrigerant that flows out of the compressor to the air conditioner and battery. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-037294 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, rolling bearings and sliding bearings have traditionally been used as bearings to support the rotating shaft of, for example, a vehicle's power source (engine or motor). However, when rolling bearings are used in motors such as electric vehicles, the rotating shaft of the motor rotates at high speeds of, for example, over 30,000 rpm, causing problems with rolling fatigue and shortening the bearing's lifespan. On the other hand, when a typical sliding bearing that uses oil as a lubricant is used in a motor, loss due to oil agitation resistance caused by the motor's rotating shaft increases.

[0005] Therefore, the present inventors considered applying a motor to a refrigerant circulation system such as the one described above, and using a sliding bearing that uses as its lubricant the refrigerant circulated in this system, particularly a CO2 refrigerant that is liquefied when compressed by a compressor, for the motor's rotating shaft. In this case, it would be desirable to be able to appropriately share the refrigerant circulation system between a motor that uses a refrigerant and an air conditioner or other device that also uses a refrigerant. For example, it would be desirable to construct a system that allows the refrigerant supply destination to be switched between the motor and the air conditioner or other device as needed.

[0006] The present invention has been made to solve the problems of the conventional technology described above, and has an object to enable a refrigerant circulation system to be shared appropriately between an air conditioner and a motor equipped with a sliding bearing that uses a refrigerant as a lubricant. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention provides a refrigerant circulation system that circulates a refrigerant containing CO2, comprising: a compressor that compresses the refrigerant, a rotor and a stator, a rotating shaft connected to the rotor, and a sliding bearing that supports the rotating shaft, the motor being configured to receive the refrigerant compressed by the compressor and to lubricate the sliding bearing using the refrigerant as a lubricant; an air conditioner that conditions the air using the refrigerant compressed by the compressor; and a switching mechanism configured to be able to switch between a first state in which the refrigerant is supplied only to the motor, and a second state in which the refrigerant is supplied to both the motor and the air conditioner.

[0008] In the present invention configured in this manner, refrigerant (containing CO2 as its main component) compressed by the compressor is supplied to the motor, and the refrigerant lubricates the motor's sliding bearings, eliminating rolling fatigue in the rolling bearings and oil agitation resistance in oil-based sliding bearings. Furthermore, in the present invention, the refrigerant circulation system is shared between the motor and the air conditioner, which also use the refrigerant, making it possible to realize a refrigerant circulation system that is low-cost, lightweight, and simple compared to systems using separate refrigerant circulation systems for the motor and the air conditioner. In particular, the present invention uses a switching mechanism to switch between a first state in which refrigerant is supplied only to the motor and a second state in which refrigerant is supplied to both the motor and the air conditioner, depending on the situation, allowing the refrigerant circulation system to be shared appropriately between the motor and the air conditioner.

[0009] In the present invention, it is preferable that the system further includes a battery that supplies power to drive the motor, and the switching mechanism is configured to be able to switch between a third state in which refrigerant is supplied to the motor and the battery, and a fourth state in which refrigerant is supplied to the motor, air conditioner, and battery, in addition to the first and second states. According to the present invention configured as described above, it is possible to realize a low-cost, lightweight, and simple refrigerant circulation system that supplies refrigerant to the motor, air conditioner, and battery. In addition, by using a switching mechanism to switch between the first to fourth states depending on the situation, it is possible to appropriately share the refrigerant circulation system between the motor, air conditioner, and battery.

[0010] In the present invention, preferably, the switching mechanism is an electromagnetic valve having a movable member operated by electromagnetic force and a housing member that houses the movable member, and is configured so that the supply destination of the refrigerant compressed by the compressor can be switched by the movable member moving within the housing member, and the switching mechanism further has an annular sealing member provided on the movable member so as to seal a gap between the movable member and the housing member, and the sealing member of the switching mechanism has a first end portion located at one end, a second end portion located at the other end, and a joint portion where the first end portion and the second end portion engage, and the first end portion of the sealing member is provided at one end in a thickness direction perpendicular to the circumferential direction of the sealing member and on the sliding surface side of the housing member that slides against the sealing member, and has a first protrusion protruding in the circumferential direction, and a second protrusion protruding in the circumferential direction at the other end in the thickness direction and on the sliding surface side a first second convex portion provided at one end in the thickness direction and on the sliding surface side, and protruding in the circumferential direction, and a first recessed portion provided between the first first convex portion and the first second convex portion and on the sliding surface side, and recessed in the circumferential direction; a second first recessed portion provided at the other end in the thickness direction and on the sliding surface side, and recessed in the circumferential direction; and a second convex portion provided between the second first recess and the second second recessed portion and on the sliding surface side, and protruding in the circumferential direction; and the sealing member is configured such that when the first end and the second end engage at the joint portion, the first first convex portion of the first end is received in the second first recessed portion of the second end, the second convex portion of the second end is received in the first recessed portion of the first end, and the first second convex portion of the first end is received in the second second recessed portion of the second end.

[0011] In the present invention configured as described above, the sealing member of the switching mechanism has a gap structure in which two protrusions and recesses at the first end engage with two recesses and protrusions at the second end, forming multiple bent portions in the passage within the gap and increasing the passage length within the gap. This increases flow resistance within the gap, preventing refrigerant from passing through the gap (passage) within the gap. Therefore, the present invention improves the sealing performance at the gap where the first end and second end of the sealing member engage. As a result, the sealing member of the switching mechanism reliably prevents refrigerant leakage between the movable member and the housing member within the switching mechanism while ensuring low friction. In particular, the present invention makes it possible to prevent leakage of refrigerants used at very high pressures (e.g., CO2 refrigerants).

[0012] In the present invention, the seal member of the switching mechanism is preferably provided on the outer periphery of the movable member, and the switching mechanism further has a rotation prevention mechanism for fixing the seal member to the movable member in the circumferential direction. According to the present invention configured in this manner, it is possible to prevent the seal member from moving (that is, rotating) in the circumferential direction and the abutment portion of the seal member from getting caught on the intake port or the discharge port of the containing member.

[0013] In the present invention, the motor is preferably configured to cool the rotor or the stator using a refrigerant. According to the present invention configured in this manner, the refrigerant can be used to both lubricate and cool the motor, which makes it possible to simplify the system and reduce costs compared to systems that perform these functions separately. [Effects of the Invention]

[0014] According to the present invention, a refrigerant circulation system can be appropriately shared between an air conditioner and a motor equipped with a sliding bearing that uses a refrigerant as a lubricant. [Brief explanation of the drawings]

[0015] [Figure 1]1 is a schematic configuration diagram of a vehicle to which a refrigerant circulation system according to an embodiment of the present invention is applied; [Figure 2] 1 is a schematic configuration diagram of a motor according to an embodiment of the present invention. [Figure 3] FIG. 2 is a schematic configuration diagram of a switching mechanism according to an embodiment of the present invention. [Figure 4] 5A and 5B are explanatory diagrams illustrating an example of switching of a supply destination of a refrigerant by a switching mechanism according to an embodiment of the present invention. [Figure 5] 2 is a schematic plan view of a seal member according to an embodiment of the present invention; FIG. [Figure 6] FIG. 3 is an enlarged perspective view showing a joint portion of the sealing member according to the embodiment of the present invention. [Figure 7] 3 is an enlarged perspective view of a first end portion of a sealing member according to an embodiment of the present invention. FIG. [Figure 8] 4 is an enlarged perspective view of a second end portion of a sealing member according to an embodiment of the present invention. FIG. [Figure 9] 5A and 5B are explanatory diagrams illustrating the flow of a refrigerant at a gap portion of a seal member according to an embodiment of the present invention. [Figure 10] 5A and 5B are explanatory diagrams of a rotation prevention mechanism of a switching mechanism according to an embodiment of the present invention. [Figure 11] FIG. 10 is a schematic configuration diagram of a switching mechanism according to a modified example of the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, a refrigerant circulation system according to an embodiment of the present invention will be described with reference to the accompanying drawings.

[0017] [Overall configuration] First, the overall configuration of a refrigerant circulation system according to this embodiment will be described with reference to Fig. 1. Fig. 1 is a schematic diagram of a vehicle to which the refrigerant circulation system according to this embodiment is applied.

[0018] 1, vehicle 200 is, for example, an electric vehicle, and includes a refrigerant circulation system 100 that circulates a refrigerant in a refrigeration cycle. This refrigerant circulation system 100 includes a motor (electric motor) 1 that generates power to drive vehicle 200, an air conditioner 2 that conditions the interior of vehicle 200, a battery 3 that supplies power to drive motor 1, a compressor 5 that compresses the refrigerant, a heat exchanger (condenser) 6 that includes a condenser, a fan, etc., and that cools the refrigerant compressed by compressor 5, and a switching mechanism 7 that is configured to be able to selectively supply the refrigerant cooled by heat exchanger 6 to at least one of motor 1, air conditioner 2, and battery 3 (i.e., be able to switch the supply destination).

[0019] The refrigerant circulation system 100 circulates a CO2 refrigerant (which may contain refrigeration oil, additives, etc.) as a natural refrigerant. To this end, the compressor 5 is configured to compress the refrigerant to extremely high pressures. The motor 1 is configured to function as an expansion valve and an evaporator in the refrigeration cycle by using the refrigerant compressed by the compressor 5 to lubricate the sliding bearings that support the rotating shaft and to cool the rotor and stator (details will be described later). The refrigerant compressed by the compressor 5 is used for air conditioning (cooling) in the air conditioner 2 and also for cooling the battery 3. For example, in the refrigerant circulation system 100, a high-temperature liquid refrigerant is supplied from the compressor 5 to the heat exchanger 6, a cold / hot liquid refrigerant is supplied from the heat exchanger 6 to the motor 1, etc., and a high-temperature gaseous refrigerant is supplied from the motor 1, etc. to the compressor 5. In this case, the motor 1 is cooled by the latent heat of vaporization of the refrigerant.

[0020] 1 shows a refrigerant circulation system 100 that uses a refrigerant to perform cooling, but the refrigerant can also be used to heat the vehicle 200 (such as heating the air conditioner 2 or heating the battery 3), that is, a heating cycle can also be performed. A refrigerant circulation system that performs such heating is provided separately from the refrigerant circulation system 100 shown in FIG. 1 (although most of the components are shared). A refrigerant circulation system that uses a refrigerant to perform heating has a similar configuration to the refrigerant circulation system 100, and therefore will not be described or illustrated in this specification.

[0021] [Motor configuration] Next, the configuration of the motor 1 according to this embodiment will be described with reference to Fig. 2. Fig. 2 is a schematic diagram of the motor 1 according to this embodiment. Specifically, Fig. 2 is a cross-sectional view of the motor 1 as seen along the axial direction.

[0022] As shown in Figure 2, the motor 1 is a system that mainly includes a rotor 11, a stator 12, a rotating shaft 13 that is connected to the rotor 11 and has one end connected to a transaxle (not shown) of the vehicle 200, a pair of plain bearings 14 that support the rotating shaft 13, and a housing 15 that houses the rotor 11, stator 12, rotating shaft 13, plain bearings 14, etc.

[0023] The motor 1 also has a refrigerant supply passage 16 that supplies the refrigerant compressed by the compressor 5 to the sliding bearing 14. More specifically, the refrigerant supply passage 16 supplies the refrigerant to the gap between the rotating shaft 13 and the sliding bearing 14. The sliding bearing 14 is configured to be lubricated using the refrigerant (CO2 refrigerant) supplied from the refrigerant supply passage 16 in this way as a lubricant. Typically, the sliding bearing 14 is lubricated using a liquid refrigerant.

[0024] If a rolling bearing is applied to the motor 1, for example in an electric vehicle, the rotating shaft 13 of the motor 1 rotates at a high rotation speed of, for example, over 30,000 rpm, causing a problem of reduced lifespan due to rolling fatigue. On the other hand, if a typical sliding bearing that uses oil is applied to the motor 1, the loss of oil agitation resistance caused by the rotating shaft 13 becomes large. Therefore, in this embodiment, a sliding bearing 14 that uses a refrigerant (CO2 refrigerant) that has been liquefied by compression by the compressor 5 is applied to the motor 1. This solves problems such as rolling fatigue and oil agitation resistance.

[0025] The refrigerant used as a lubricant in the sliding bearing 14 is then supplied to the rotor 11 and stator 12 and used for cooling. Specifically, in motor 1, a coil (not shown) is provided on stator 12, and the refrigerant is used to cool the coil of stator 12 (note that in a motor in which a coil is provided on rotor 11, the refrigerant can simply be used to cool the coil of rotor 11). Motor 1 functions as an expansion valve because the refrigerant is supplied from the gap between rotating shaft 13 and sliding bearing 14 to the space within housing 15 in which rotor 11 and stator 12 are provided and reduced in pressure, and also functions as an evaporator because this refrigerant exchanges heat with the relatively high-temperature stator 12 and other components. The refrigerant used for cooling (heat exchange) in this way is then discharged from refrigerant discharge passage 17 of motor 1 and returned to compressor 5 (FIG. 1). 2, the refrigerant is not limited to being supplied to the rotor 11 and the stator 12 via the sliding bearing 14, but may be supplied directly to the rotor 11 and the stator 12. In this case, it is preferable to supply (inject) the refrigerant to the rotor 11 and the stator 12 via an expansion valve.

[0026] Motor 1 also has a seal member 18 for sealing sliding bearing 14 provided on the side of rotating shaft 13 that is connected to a transaxle or the like. This seal member 18 is provided in housing 15 so as to prevent refrigerant from leaking to the outside from the gap between sliding bearing 14 and rotating shaft 13. On the other hand, such a seal member 18 is not provided on sliding bearing 14 on the opposite side to the side of rotating shaft 13 that is connected to a transaxle or the like, and the gap between sliding bearing 14 and rotating shaft 13 is sealed by being covered by housing 15.

[0027] [Switching mechanism configuration] Next, the configuration of the switching mechanism 7 according to this embodiment will be described with reference to Fig. 3. Fig. 3 is a schematic configuration diagram of the switching mechanism 7 according to this embodiment. Specifically, Fig. 3 shows a cross-sectional view of the switching mechanism 7.

[0028] As shown in FIG. 3, the switching mechanism 7 is an electromagnetic valve (solenoid valve) having a movable member (spool) 71 that operates by electromagnetic force, a cylindrical housing member (cylinder) 72 that houses the movable member 71 and defines the space in which the movable member 71 moves, and a coil (solenoid coil) 73 that is arranged to surround the movable member 71 and drives the movable member 71. The switching mechanism 7 may further include a spring (not shown) that biases the movable member 71. The switching mechanism 7 is controlled by a control device (not shown) in accordance with the conditions (such as the temperature of the battery 3) and requirements (such as a cooling requirement) of the vehicle 200. In this case, the control device controls the energization of the coil 73 of the switching mechanism 7.

[0029] Specifically, the movable member 71 has a centrally located shaft portion 71a extending in the direction of movement of the movable member 71, and four enlarged-diameter portions 71b, 71c, 71d, and 71e provided on the shaft portion 71a. The four enlarged-diameter portions 71b, 71c, 71d, and 71e have diameters larger than the shaft portion 71a, particularly diameters approximately the same as (slightly smaller than) the inner diameter of the housing member 72. An annular seal member 80 is attached to the outer periphery of each of the enlarged-diameter portions 71b, 71c, 71d, and 71e to seal gaps between the enlarged-diameter portions 71b, 71c, 71d, and 71e and the housing member 72. The seal member 80 is fitted into grooves formed in the outer wall surfaces of the enlarged-diameter portions 71b, 71c, 71d, and 71e. When the movable member 71 moves, the seal member 80 provided on the movable member 71 slides against the inner wall surface (sliding surface) of the housing member 72. The details of the seal member 80 will be described later.

[0030] The accommodating member 72 also has first and second intake ports 72a, 72b through which the refrigerant compressed by the compressor 5 (in other words, the refrigerant cooled by the heat exchanger 6) is supplied, a first discharge port 72c for supplying the refrigerant to the motor 1, a second discharge port 72d for supplying the refrigerant to the air conditioner 2, and a third discharge port 72e for supplying the refrigerant to the battery 3.

[0031] The switching mechanism 7 is configured so that the movable member 71 moves within the accommodating member 72 by the coil 73 (moves left and right in FIG. 3), thereby switching the supply destination of the refrigerant compressed by the compressor 5 in accordance with the relative positions of the enlarged diameter portions 71b, 71c, 71d, and 71e of the movable member 71 with respect to the first and second suction ports 72a, 72b and the first to third discharge ports 72c, 72d, and 72e of the accommodating member 72. In other words, the switching mechanism 7 is configured as a multi-way valve (five-way valve).

[0032] An example of switching the supply destination of the refrigerant by the switching mechanism 7 in this embodiment will now be described with reference to Fig. 4. Each of Figs. 4(A), (B), and (C) shows the same switching mechanism 7 as in Fig. 3.

[0033] First, FIG. 4A shows a state (first state) of the switching mechanism 7 in which the refrigerant is supplied only to the motor 1. In this state, the movable member 71 is positioned within the accommodating member 72 so that the refrigerant flows only from the second intake port 72b to the first outlet port 72c within the switching mechanism 7. Next, FIG. 4B shows a state (second state) of the switching mechanism 7 in which the refrigerant is supplied to both the motor 1 and the air conditioner 2 (but not to the battery 3). In this state, the movable member 71 is positioned within the accommodating member 72 so that the refrigerant flows from the second intake port 72b to the first outlet port 72c within the switching mechanism 7 and from the first intake port 72a to the second outlet port 72d within the switching mechanism 7. Next, FIG. 4C shows a state (third state) of the switching mechanism 7 in which the refrigerant is supplied to both the motor 1 and the battery 3 (but not to the air conditioner 2). In this state, the movable member 71 is positioned within the accommodating member 72 so that the refrigerant flows from the second suction port 72b to the first discharge port 72c within the switching mechanism 7 and from the first suction port 72a to the third discharge port 72e.

[0034] 4(A) to 4(C), the switching mechanism 7 can switch the destination of the refrigerant supply in various ways by positioning the movable member 71 in various locations within the accommodating member 72. For example, the switching mechanism 7 can switch between a state (fourth state) in which the refrigerant is supplied to all of the motor 1, the air conditioner 2, and the battery 3, a state in which the refrigerant is not supplied to any of the motor 1, the air conditioner 2, and the battery 3, and a state in which the refrigerant is supplied only to the air conditioner 2 and the battery 3.

[0035] Next, the seal member 80 according to this embodiment will be described in detail with reference to Figures 5 to 8. First, Figure 5 is a schematic plan view showing the overall configuration of the seal member 80 according to this embodiment. As shown in Figure 5, the seal member 80 has a first end 81 and a second end 82, each of which is located at one end and the other end and has an uneven shape, and these first end 81 and second end 82 engage with each other at a joint 83, thereby forming an annular shape as a whole.

[0036] Next, the structure of the abutment 83 (abutment structure) of the seal member 80 according to this embodiment will be described in detail with reference to Figures 6 to 8. Figure 6 is an enlarged perspective view of the abutment 83 of the seal member 80 according to this embodiment, Figure 7 is an enlarged perspective view of the first end 81 of the seal member 80 according to this embodiment, and Figure 8 is an enlarged perspective view of the second end 82 of the seal member 80 according to this embodiment.

[0037] As shown in FIG. 7, the first end 81 of the sealing member 80 has a first first convex portion 81a that is provided at one end in the thickness direction (direction perpendicular to the circumferential direction (width direction)) and on the sliding surface side of the accommodating member 72 and protrudes in the circumferential direction, a first second convex portion 81c that is provided at the other end in the thickness direction and on the sliding surface side and protrudes in the circumferential direction, a first recessed portion 81b that is provided between the first first convex portion 81a and the first second convex portion 81c and on the sliding surface side and is recessed in the circumferential direction, and a third recessed portion 81d that is provided on the opposite side of the sliding surface and is recessed in the circumferential direction and extends throughout the thickness direction.

[0038] As shown in FIG. 8, the second end 82 of the sealing member 80 has a second first recess 82a that is recessed in the circumferential direction and is provided at one end in the thickness direction on the sliding surface side of the accommodating member 72, a second second recess 82c that is recessed in the circumferential direction and is provided at the other end in the thickness direction on the sliding surface side, a second convex portion 82b that is provided between the second first recess 82a and the second second recess 82c on the sliding surface side and protrudes in the circumferential direction, and a third convex portion 82d that is provided on the opposite side from the sliding surface and protrudes in the circumferential direction and extends over the entire thickness direction.

[0039] Furthermore, as shown in Figures 6 to 8, when the first end 81 and the second end 82 of the sealing member 80 engage with each other at the joint portion 83, the first first convex portion 81a of the first end 81 is received in the second first concave portion 82a of the second end 82, the second convex portion 82b of the second end 82 is received in the first concave portion 81b of the first end 81, the first second convex portion 81c of the first end 81 is received in the second second concave portion 82c of the second end 82, and the third convex portion 82d of the second end 82 is received in the third concave portion 81d of the first end 81.

[0040] Next, the flow of refrigerant at the gap 83 of the seal member 80 according to this embodiment will be described with reference to Fig. 9. Like Fig. 6, Fig. 9 is an enlarged perspective view of the gap 83 of the seal member 80, with the first end 81 and the second end 82 indicated by dashed lines and solid lines, respectively. Here, an example will be given of a case where refrigerant is supplied to the seal member 80 from top to bottom in Fig. 9.

[0041] In this case, when the refrigerant compressed by compressor 5 flows through switching mechanism 7, it is considered that the refrigerant will attempt to flow through joint portion 83 of seal member 80 provided on movable member 71 as shown by the arrows in Fig. 9. Specifically, the refrigerant will attempt to flow through the gap between first first convex portion 81a of first end portion 81 and second first concave portion 82a of second end portion 82, the gap between first concave portion 81b of first end portion 81 and second convex portion 82b of second end portion 82, and the gap between first second convex portion 81c of first end portion 81 and second second concave portion 82c of second end portion 82, in this order.

[0042] However, due to the abutment structure that engages the two convex portions and concave portions of first end 81 with the two concave portions and convex portions of second end 82, there are multiple bent portions in the passage within abutment 83, and the passage length within abutment 83 is increased. Therefore, the flow path resistance within abutment 83 increases, and the refrigerant does not pass through the gap (passage) within abutment 83 as described above.

[0043] Therefore, according to the present embodiment, it is possible to improve the sealing performance at the joint portion 83 where the first end portion 81 and the second end portion 82 of the seal member 80 engage with each other. As a result, according to the present embodiment, the seal member 80 can reliably prevent refrigerant leakage between the movable member 71 and the accommodating member 72 in the switching mechanism 7. In particular, according to the present embodiment, it is possible to reliably prevent leakage of a refrigerant (CO refrigerant) used at extremely high pressure.

[0044] According to an experiment conducted by the present inventors, when a seal member having flat portions without any irregularities and simply butting one end against the other end is used as a reference, it was found that the seal member 80 according to this embodiment can reduce leakage by about 90%. Therefore, it was found that the seal member 80 according to this embodiment can provide extremely high sealing performance.

[0045] On the other hand, there is a method of using an O-ring as a sealing member, but when attempting to seal high-pressure gas, O-rings experience high friction at all times, resulting in problems such as deterioration due to wear. In contrast, with the sealing member 80 of this embodiment, friction increases only when pressure is generated, making it possible to reduce friction loss compared to when an O-ring is used. Furthermore, with the sealing member 80, the pressure on the back surface of the sealing member 80 increases when pressure is generated, thereby improving sealing performance.

[0046] In Figure 9, an example is given in which the refrigerant is supplied to the sealing member 80 from top to bottom, but it goes without saying that the sealing member 80 can also provide very high sealing performance when the refrigerant is supplied to the sealing member 80 from bottom to top.

[0047] In this embodiment, the switching mechanism 7 further includes a rotation-preventing mechanism for fixing the seal member 80 to the movable member 71 in the circumferential direction. This rotation-preventing mechanism will be described with reference to FIG. 10. FIG. 10 is a cross-sectional view of the expanded diameter portion 71b of the movable member 71 in the switching mechanism 7 and the seal member 80, taken along line XX in FIG. 3. Note that the rotation-preventing mechanism will be described here as a representative of the expanded diameter portions 71b, 71c, 71d, and 71e, but similar rotation-preventing mechanisms are also applicable to the other expanded diameter portions 71c, 71d, and 71e.

[0048] 10, a protrusion 71g is provided on a portion of the outer periphery of enlarged diameter portion 71b of movable member 71, and a recess 85 that engages with protrusion 71g is provided on seal member 80. Protrusion 71g and recess 85 form anti-rotation mechanism 75 for fixing seal member 80 in the circumferential direction to movable member 71. Anti-rotation mechanism 75 like this can prevent seal member 80 from moving (i.e., rotating) in the circumferential direction and causing joint portion 83 to become caught on suction ports 72a, 72b or discharge ports 72c, 72d, and 72e of accommodating member 72 (not shown).

[0049] [Action and effect] Next, the operation and effects of the refrigerant circulation system 100 according to this embodiment will be described.

[0050] According to this embodiment, the refrigerant circulation system 100 includes a compressor 5 that compresses a refrigerant containing CO2, a rotor 11 and a stator 12, a rotating shaft 13 connected to the rotor 11, and a sliding bearing 14 that supports the rotating shaft 13, and is configured so that the refrigerant compressed by the compressor 5 is supplied to the sliding bearing 14 and the sliding bearing 14 uses the refrigerant as a lubricant for lubrication; an air conditioner 2 that performs air conditioning using the refrigerant compressed by the compressor 5; and a switching mechanism 7 that is configured to be able to switch between a first state in which the refrigerant is supplied only to the motor 1 and a second state in which the refrigerant is supplied to both the motor 1 and the air conditioner 2.

[0051] In this embodiment, refrigerant compressed by the compressor 5 is supplied to the motor 1, and the sliding bearings 14 of the motor 1 are lubricated by the refrigerant, eliminating rolling fatigue in the rolling bearings and oil agitation resistance in the sliding bearings that use oil. Furthermore, in this embodiment, the refrigerant circulation system 100 is shared between the motor 1, which uses a refrigerant, and the air conditioner 2, which also uses a refrigerant. This makes it possible to realize a refrigerant circulation system 100 that is low-cost, lightweight, and simple compared to using separate refrigerant circulation systems for the motor 1 and the air conditioner 2. Furthermore, in this embodiment, the switching mechanism 7 can be used to switch between a first state in which refrigerant is supplied only to the motor 1 and a second state in which refrigerant is supplied to both the motor 1 and the air conditioner 2, depending on the situation, allowing the refrigerant circulation system 100 to be shared appropriately between the motor 1 and the air conditioner 2.

[0052] Furthermore, according to this embodiment, the refrigerant circulation system 100 further includes a battery 3 that supplies power to drive the motor 1, and the switching mechanism 7 is configured to be able to switch between a third state in which the refrigerant is supplied to the motor 1 and the battery 3, and a fourth state in which the refrigerant is supplied to the motor 1, the air conditioner 2, and the battery 3, in addition to the first and second states. This makes it possible to realize a low-cost, lightweight, and simple refrigerant circulation system 100 that supplies refrigerant to the motor 1, the air conditioner 2, and the battery 3. Furthermore, because the switching mechanism 7 is used to switch between the first to fourth states depending on the situation, the refrigerant circulation system 100 can be appropriately shared between the motor 1, the air conditioner 2, and the battery 3.

[0053] Furthermore, according to this embodiment, the switching mechanism 7 is an electromagnetic valve having a movable member 71 that operates by electromagnetic force and a housing member 72 that houses the movable member 71, and is configured to be able to switch the supply destination of the refrigerant compressed by the compressor 5 by moving the movable member 71 inside the housing member 72, and the switching mechanism 7 further has a seal member 80 that is formed in an annular shape and is provided on the movable member 71 so as to seal the gap between the movable member 71 and the housing member 72, and the seal member 80 of the switching mechanism 7 has a first end 81 located at one end, a second end 82 located at the other end, and a joint portion 83 at which the first end 81 and the second end 82 engage, and the first end 81 of the seal member 80 is provided at one end in the thickness direction and on the sliding surface side and includes a first first protrusion 81a that protrudes in the circumferential direction, and a first second protrusion 81c that is provided at the other end in the thickness direction and on the sliding surface side and protrudes in the circumferential direction, and The second end 82 of the sealing member 80 has a first recess 81b recessed in the circumferential direction, which is provided between the first recess 82a and the first second protrusion 81c and on the sliding surface side, and a second first recess 82a recessed in the circumferential direction, which is provided at one end in the thickness direction and on the sliding surface side, a second second recess 82c recessed in the circumferential direction, which is provided at the other end in the thickness direction and on the sliding surface side, and a second second recess 82c recessed in the circumferential direction, which is provided between the second first recess 82a and the second second recess 82c and on the sliding surface side, which protrudes in the circumferential direction. The sealing member 80 has a first protrusion 81a of the first end 81 and a second protrusion 82b, and is configured so that when the first end 81 and the second end 82 engage at the joint 83, the first first protrusion 81a of the first end 81 is received in the second first recess 82a of the second end 82, the second protrusion 82b of the second end 82 is received in the first recess 81b of the first end 81, and the first second protrusion 81c of the first end 81 is received in the second second recess 82c of the second end 82.

[0054] In the present embodiment, the abutment structure that engages the two convex and concave portions of the first end 81 with the two concave and convex portions of the second end 82 forms multiple bent portions in the passage within the abutment 83, and also increases the passage length within the abutment 83. This increases the flow resistance within the abutment 83, thereby preventing the refrigerant from passing through the gap (passage) within the abutment 83. Therefore, the present embodiment improves the sealing performance of the abutment 83, where the first end 81 and the second end 82 engage with each other, in the seal member 80. As a result, the present embodiment ensures low friction and reliably prevents refrigerant leakage between the movable member 71 and the accommodating member 72 within the switching mechanism 7. In particular, the present embodiment makes it possible to prevent leakage of a refrigerant (CO refrigerant) used at extremely high pressure.

[0055] Furthermore, according to the present embodiment, the sealing member 80 of the switching mechanism 7 is provided on the outer periphery of the movable member 71, and the switching mechanism 7 further includes an anti-rotation mechanism 75 for fixing the sealing member 80 to the movable member 71 in the circumferential direction. This prevents the sealing member 80 from moving (i.e., rotating) in the circumferential direction and causing the abutment portion 83 of the sealing member 80 to get caught on the intake port or discharge port of the accommodating member 72.

[0056] Furthermore, according to this embodiment, the motor 1 is configured to use a refrigerant to cool the rotor 11 and the stator 12. This allows the refrigerant to be used both to lubricate and cool the motor 1, which makes it possible to simplify the system and reduce costs compared to systems that perform these functions separately.

[0057] [Variations] In the above-described embodiment, the switching mechanism 7 is configured to move the movable member 71 in the axial direction within the housing member 72, but the present invention is not limited to using such a switching mechanism 7. A switching mechanism according to a modification of this embodiment will be described with reference to Fig. 11. Figs. 11(A), (B), and (C) are cross-sectional views of the switching mechanism according to the modification.

[0058] 11(A), (B), and (C), the switching mechanism 7a according to the modified example mainly includes a cylindrical movable member 91 that rotates and a cylindrical housing member 92 that tightly houses the movable member 91. Specifically, the movable member 91 has five outlets 91a to 91e. The housing member 92 is formed with an intake port 92a through which the refrigerant compressed by the compressor 5 (in other words, the refrigerant cooled by the heat exchanger 6) is supplied, a first outlet 92b through which the refrigerant is supplied to the motor 1, a second outlet 92c through which the refrigerant is supplied to the air conditioner 2, and a third outlet 92d through which the refrigerant is supplied to the battery 3.

[0059] The switching mechanism 7a according to the modified example is configured to be able to switch the supply destination of the refrigerant compressed by the compressor 5 in accordance with the relative positions of each of the discharge ports 91a to 91e of the movable member 91 with respect to the suction port 92a and first to third discharge ports 92b, 92c, 92d of the accommodating member 92, by rotating the movable member 91 within the accommodating member 92 by, for example, electromagnetic force. In other words, the switching mechanism 7a is configured as a multi-way valve (four-way valve).

[0060] Specifically, FIG. 11A shows a state (first state) of the switching mechanism 7a in which refrigerant is supplied only to the motor 1. In this state, the movable member 91 is positioned within the housing member 92 so that the refrigerant flows only from the suction port 92a through the discharge ports 91a and 91d to the first discharge port 92b. FIG. 11B shows a state (second state) of the switching mechanism 7a in which refrigerant is supplied to both the motor 1 and the air conditioner 2 (but not to the battery 3). In this state, the movable member 91 is positioned within the housing member 92 so that the refrigerant flows from the suction port 92a through the discharge ports 91a, 91b, and 91d to the first discharge port 92b and the second discharge port 92c. FIG. 11C shows a state (fourth state) of the switching mechanism 7a in which refrigerant is supplied to all of the motor 1, the air conditioner 2, and the battery 3. In this state, the movable member 91 is positioned within the accommodating member 92 so that the refrigerant flows from the intake port 92a through the discharge ports 91a to 91e to the first discharge port 92b, the second discharge port 92c, and the third discharge port 92d within the switching mechanism 7a. [Explanation of symbols]

[0061] 1 motor 2. Air Conditioner 3 Battery 5. Compressor 6 Heat exchanger 7, 7a Switching mechanism 11 rotor 12 Stator 13 Rotation axis 14 Plain bearings 71, 91 Movable parts 72, 92 Storage member 75 Anti-rotation mechanism 80 sealing material 81 First end 82 Second end 83 Joint section 100 Refrigerant Circulation System 200 vehicles

Claims

1. CO 2 A refrigerant circulation system that circulates a refrigerant including: a compressor that compresses the refrigerant; a motor including a rotor and a stator, a rotating shaft connected to the rotor, and a sliding bearing supporting the rotating shaft, wherein the refrigerant compressed by the compressor is supplied and the sliding bearing uses the refrigerant as a lubricant for lubrication; an air conditioner that performs air conditioning using the refrigerant compressed by the compressor; a switching mechanism configured to be able to switch between a first state in which the refrigerant is supplied only to the motor and a second state in which the refrigerant is supplied to both the motor and the air conditioner; A refrigerant circulation system comprising:

2. further comprising a battery for supplying power to drive the motor; The switching mechanism is configured to be able to switch between a third state in which the refrigerant is supplied to the motor and the battery, and a fourth state in which the refrigerant is supplied to the motor, the air conditioner, and the battery, in addition to the first and second states. The refrigerant circulation system of claim 1 .

3. the switching mechanism is an electromagnetic valve having a movable member that operates by electromagnetic force and a housing member that houses the movable member, and is configured to be able to switch a supply destination of the refrigerant compressed by the compressor by moving the movable member within the housing member; the switching mechanism further includes a sealing member formed in an annular shape and provided on the movable member so as to seal a gap between the movable member and the accommodating member; the sealing member of the switching mechanism includes a first end portion located at one end, a second end portion located at the other end, and a joint portion where the first end portion and the second end portion engage with each other; the first end of the sealing member has: a first first convex portion that is provided at one end of the sealing member in a thickness direction perpendicular to the circumferential direction and on the sliding surface side of the containing member that slides against the sealing member, and that protrudes in the circumferential direction; a first second convex portion that is provided at the other end in the thickness direction and on the sliding surface side, and that protrudes in the circumferential direction; and a first concave portion that is provided between the first first convex portion and the first second convex portion and on the sliding surface side, and that is recessed in the circumferential direction, the second end of the sealing member has: a second first recess provided at one end in the thickness direction and on the sliding surface side, and recessed in the circumferential direction; a second second recess provided at the other end in the thickness direction and on the sliding surface side, and recessed in the circumferential direction; and a second protrusion provided between the second first recess and the second second recess and on the sliding surface side, and protruding in the circumferential direction, The sealing member is configured such that, when the first end and the second end engage with each other at the joint portion, the first first convex portion of the first end is received in the second first concave portion of the second end, the second convex portion of the second end is received in the first concave portion of the first end, and the first second convex portion of the first end is received in the second second concave portion of the second end. The refrigerant circulation system of claim 1 .

4. the sealing member of the switching mechanism is provided on an outer periphery of the movable member, the switching mechanism further includes a rotation prevention mechanism for fixing the seal member to the movable member in the circumferential direction. The refrigerant circulation system according to claim 3 .

5. The refrigerant circulation system according to claim 1 , wherein the motor is configured to cool the rotor or the stator using the refrigerant.

Images