Cooling system of rotating electric machine

Abstract

The purpose of the present invention is to provide a cooling system for a rotating electric machine, which can improve the cooling effect of the rotating electric machine by changing the flow rate ratio of a refrigerant supplied to a stator and a refrigerant supplied to a rotor. This cooling system (1) for a rotating electrical machine is provided with: a refrigerant flow path (7) to which a refrigerant is supplied; a switching mechanism (3) for switching the form of the refrigerant flow path (7); and a pump (4) for pressure-feeding the refrigerant to the refrigerant flow path (7). The refrigerant flow path (7) has: a first refrigerant flow path part (71) for supplying a refrigerant to the core (21A) of the stator (21); and a second refrigerant flow path section (72) for supplying a refrigerant to the rotor (22). The switching mechanism (3) is configured so as to form a first configuration in which a refrigerant is supplied to the first refrigerant flow path section (71) and not to be supplied to the second refrigerant flow path section (72), and a second configuration in which the downstream of the first refrigerant flow path section (71) and the upstream of the second refrigerant flow path section (72) communicate with each other.

Description

Technical Field

[0001] The invention relates to a cooling system for a rotating electrical machine. Background Art

[0002] Patent document 1 describes a cooling system for a rotating electric machine, which includes a refrigerant flow path (a first refrigerant flow path and a sixth refrigerant flow path) for supplying refrigerant to a first coil end and a second coil end of the rotating electric machine, and a refrigerant flow path (a fifth refrigerant flow path) for supplying refrigerant to a magnet of the rotating electric machine (paragraphs 0027, 0031, and 0032). The first coil end and the second coil end are arranged in a stator, and the refrigerant flow paths (the first refrigerant flow path and the sixth refrigerant flow path) constitute a refrigerant flow path for supplying refrigerant to the stator. The magnet is arranged on a rotor, and the refrigerant flow path (the fifth refrigerant flow path) constitutes a refrigerant flow path for supplying refrigerant to the rotor. The fifth refrigerant flow path is configured to branch from the first refrigerant flow path so that a portion of the refrigerant flowing through the first refrigerant flow path flows to the magnet of the rotor (paragraph 0031). Prior art literature Patent Literature

[0003] Patent document 1: Japanese Patent Application Publication No. 2019-161898. Summary of the invention Problem that the invention aims to solve

[0004] In the cooling system of the rotating electrical machine of Patent Document 1, the connection state of the first refrigerant flow path and the fifth refrigerant flow path does not change. Therefore, the flow rate of the refrigerant supplied to the stator and the flow rate of the refrigerant supplied to the rotor change in accordance with the flow rate of the refrigerant flowing in the first refrigerant flow path while maintaining a constant flow rate ratio.

[0005] An object of the present invention is to provide a cooling system for a rotating electrical machine, which can change the flow ratio of a refrigerant supplied to a stator and a refrigerant supplied to a rotor, thereby improving the cooling effect of the rotating electrical machine. Technical means of solving problems

[0006] In order to achieve the above object, a cooling system for a rotating electrical machine according to the present invention is a cooling system for a rotating electrical machine including a stator and a rotor. The cooling system comprises: a refrigerant flow path for supplying refrigerant; a switching mechanism for switching the form of the refrigerant flow path; and a pump for pressurizing the refrigerant to the refrigerant flow path. The refrigerant flow path includes: a first refrigerant flow path portion that supplies refrigerant to the core of the stator; and a second refrigerant flow path portion that supplies refrigerant to the rotor. The switching mechanism is configured to form a first state in which refrigerant is supplied to the first refrigerant flow path portion but not to the second refrigerant flow path portion, and a second state in which the downstream of the first refrigerant flow path portion communicates with the upstream of the second refrigerant flow path portion. Effects of the Invention

[0007] According to the present invention, the flow rate ratio of the refrigerant supplied to the stator and the refrigerant supplied to the rotor can be changed, and the cooling effect of the rotating electrical machine can be improved.

[0008] Problems, structures, and effects other than those described above will become clear from the following description of the embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is a diagram schematically showing the configuration of a first embodiment (Embodiment 1) of a cooling system for a rotating electrical machine according to the present invention. Figure 2 This is a schematic diagram showing a modified example (first modified example: modified example 1) of the configuration of a pump in the cooling system for the rotating electrical machine according to the first embodiment of the present invention. Figure 3 This is a schematic diagram showing a modification example (second modification example: modification example 2) of a driving source of a pump in the cooling system for the rotating electrical machine according to the first embodiment of the present invention. Figure 4 This is a schematic diagram showing a modification example (third modification example: modification example 3) of the driving source of the pump in the cooling system for the rotating electrical machine according to the first embodiment of the present invention. Figure 5 It is for Figure 1 An explanatory diagram showing a connection form of a refrigerant flow path in a cooling system for a rotating electrical machine. Figure 6 This is a diagram showing the relationship between the vehicle speed and the refrigerant supply amount in the cooling system of the rotating electrical machine according to the present invention. Figure 7 It is a schematic configuration diagram showing a modification example (fourth modification example: modification example 4) of the switching mechanism in the cooling system for the rotating electrical machine according to the first embodiment of the present invention. Figure 8 It is for Figure 7 A diagram showing the opening and closing states of valves in each speed range of a cooling system for a rotating electrical machine. Fig. 9 It is a schematic configuration diagram showing a modification example (fifth modification example: modification example 5) of the switching mechanism in the cooling system for the rotating electrical machine according to the first embodiment of the present invention. Fig.10A diagram showing the relationship between the vehicle speed and the refrigerant supply amount when the operating range of the electric pump is changed in the cooling system for a rotating electrical machine according to the present invention. DETAILED DESCRIPTION

[0010] The e-Axle, which integrates the motor, inverter and gear, has a high loss density as the output density increases. In order to cope with this high loss density, it is hoped that the cooling performance of the rotating electrical machine can be improved by a cooling system with a direct oil cooling structure. In the oil cooling structure, a pump that pressurizes the refrigerant (cooling oil) is required. As the pump, for example, a mechanical pump (mechanical oil pump) or an electric pump (electric oil pump) can be used. In addition, since the discharge volume of a mechanical pump varies according to the speed, when a mechanical pump is used, in order to ensure cooling performance at each speed, it is necessary to appropriately control the refrigerant supply amount.

[0011] In the following embodiments, an example using a mechanical pump is also described. Since the discharge volume of the mechanical pump decreases in the low speed region, the cooling performance of the rotating electric machine in the low speed region decreases. In order to prevent the reduction of the cooling performance in the low speed region, the pump is required to be large-scale. In the embodiment using a mechanical pump, the reduction of the cooling performance of the rotating electric machine in the low speed region is suppressed, thereby avoiding the large-scale pump.

[0012] In addition, in the following embodiments, the torque loss in the medium speed range which is frequently used in urban driving is reduced, thereby improving the power economy.

[0013] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0014] [Example 1] Figure 1 This is a diagram schematically showing a configuration of a first embodiment (Embodiment 1) of a cooling system 1 for a rotating electrical machine 2 according to the present invention.

[0015] The cooling system 1 of the present embodiment is a cooling system 1 of a rotating electric machine 2 having a stator 21 and a rotor 22, and comprises the rotating electric machine 2, a pump 4 for pressurizing a refrigerant (cooling oil), a refrigerant flow path 7 for flowing the refrigerant (cooling oil), a switching mechanism 3 for switching the connection states of the refrigerant flow path sections 71, 72, 73, and 74 formed in the refrigerant flow path 7, a refrigerant storage section (oil pan) 5 for storing the refrigerant, a vehicle speed sensor 9 for detecting the vehicle speed, and an electronic control unit (ECU) 6. The refrigerant of the present embodiment uses oil, which is sometimes referred to as cooling oil for explanation.

[0016] The rotating electric machine 2 includes a stator 21, a rotor 22, a housing 24 that accommodates the stator 21 and the rotor 22, and a refrigerant (cooling oil) discharge port 25. The stator 21 includes a core (stator core) 21A and a coil. Figure 1In the figure, the coil end 21B of the coil is shown. The rotor 22 has a core (rotor core) 22A and is fixed to the output shaft 23. The output shaft 23 can also be regarded as a part of the rotor 22. The housing 24 serves as a container for storing the refrigerant and is provided with a discharge port 25 for discharging the refrigerant.

[0017] The pump 4 is a component that pressurizes the refrigerant to the refrigerant flow path 7. In the present embodiment, an example of using an electric pump 41 driven by a motor 41A and a mechanical pump 42 is shown. The discharge amount of the electric pump 41 is controlled by the electronic control unit 6 according to the vehicle speed detected by the vehicle speed sensor 9. The electronic control unit (ECU) 6 is connected to the vehicle speed sensor 9 through a signal line E9 in order to receive the vehicle speed signal from the vehicle speed sensor 9. In addition, the electronic control unit (ECU) 6 is connected to the motor 41A through a signal line E41A in order to control the electric pump 41. The mechanical pump 42 uses a variable capacity pump or a fixed capacity pump. Since the discharge amount of the mechanical pump 42 changes according to the vehicle speed, the discharge amount of the electric pump 41 is controlled by the electronic control unit 6 according to the discharge amount of the mechanical pump 42.

[0018] The mechanical pump 42 sucks refrigerant from the rotating electric machine 2 side when the vehicle moves backward (when reversing). Therefore, in order to prevent the mechanical pump 42 from sucking refrigerant from the rotating electric machine 2 side when reversing, a check valve not shown in the figure may be provided on the motor side to draw refrigerant from the refrigerant storage portion (oil pan) 5 via a bypass passage not shown in the figure. In this case, the check valve may be provided in the mechanical pump 42 or between the mechanical pump 42 and the first refrigerant flow path portion 71. In addition, a bypass passage may be provided between the refrigerant storage portion (oil pan) 5 and the first refrigerant flow path portion 71 so that the refrigerant bypasses the mechanical pump 42 when the vehicle moves backward. In addition, a check valve may be provided on the bypass passage so that the refrigerant does not leak when the vehicle moves forward.

[0019] The pump 4 may be configured using either an electric pump 41 or a mechanical pump 42 . Figure 2 This is a schematic diagram showing a modified example (first modified example: Modification 1) of the configuration of the pump 4 in the cooling system 1 of the rotating electrical machine 2 according to the first embodiment of the present invention. Figure 2 , an example is shown in which the pump 4 is configured using an electric pump 41 instead of a mechanical pump 42. The discharge amount of the electric pump 41 is controlled in accordance with the vehicle speed so as to satisfy the cooling performance.

[0020] In the present embodiment, the mechanical pump 42 obtains power from the shaft (reducer shaft) of the reducer 101 provided between the rotary electric machine 2 and the drive shaft 104 .

[0021] That is, in the present embodiment, the pump 4 includes a mechanical pump 42 and an electric pump 41 , and the mechanical pump 42 obtains power from the shaft of the speed reducer 101 provided between the rotary electric machine 2 and the drive shaft 104 . However, the power of the mechanical pump 42 is not limited to the shaft of the speed reducer 101 (speed reducer shaft), and the power of the mechanical pump 42 may be obtained from other parts.

[0022] Figure 3 This is a schematic diagram showing a modification example (second modification example: modification example 2) of the driving source of the pump 4 in the cooling system 1 of the rotating electrical machine 2 of the first embodiment of the present invention. In the case of a system combined with a transmission 103, the power of the mechanical pump 42 can also be obtained from the output shaft 23 of the rotating electrical machine 2. That is, in this example, the pump 4 includes a mechanical pump 42 and an electric pump 41, and the mechanical pump 42 obtains power from the output shaft 23 of the rotating electrical machine 2. In this example, a speed reducer 11 is arranged between the output shaft 23 and the mechanical pump 42.

[0023] This case has the advantage that by obtaining power from the output shaft 23, a refrigerant corresponding to the rotation speed of the rotary electric machine 2 can be supplied, and the cooling performance can be maximized. On the other hand, a disadvantage is that since the difference between the rotation speed of the rotary electric machine 2 and the required rotation speed of the mechanical pump 42 becomes larger, the speed reducer 11 for transmitting power to the mechanical pump 42 becomes larger.

[0024] Figure 4 This is a schematic diagram showing a modification example (third modification example: modification example 3) of the driving source of the pump 4 in the cooling system 1 of the rotating electrical machine 2 of the first embodiment of the present invention. In the case of a system combined with a transmission 103, the power of the mechanical pump 42 can also be obtained from the drive shaft 104 that drives the tire 102. That is, in this example, the pump 4 includes a mechanical pump 42 and an electric pump 41, and the mechanical pump 42 obtains power from the drive shaft 104. In this example, a speed reducer 12 is arranged between the drive shaft 104 and the mechanical pump 42.

[0025] This case has the advantage that the power of the mechanical pump 42 is obtained from the drive shaft 104, so that the reducer 12 for the mechanical pump 42 can be reduced. On the other hand, it has the disadvantage that the mechanical pump 42 is enlarged in order to obtain the cooling performance under the worst conditions because the vehicle speed and the rotation speed of the rotary electric machine 2 are different depending on the state of the transmission 103.

[0026] return Figure 1 , the refrigerant flow path 7 is described. The refrigerant flow path 7 includes: a discharge side refrigerant flow path portion 70 connected to the discharge side of the pump 4, a first refrigerant flow path portion 71 that supplies refrigerant to the stator core 21A, a second refrigerant flow path portion 72 that supplies refrigerant to the rotor 22, a third refrigerant flow path portion 73 that supplies the refrigerant after cooling the stator core 21A to the coil end portion 21B, and a fourth refrigerant flow path portion 74 that supplies the refrigerant after cooling the stator core 21A to the second refrigerant flow path portion 72.

[0027] The first refrigerant flow path portion 71 is a refrigerant flow path portion formed between a branch point P1, which is a downstream end portion of the discharge-side refrigerant flow path portion 70, and the first valve 31. The upstream end portion of the first refrigerant flow path portion 71 is connected to the downstream end portion P1 of the discharge-side refrigerant flow path portion 70, and the first refrigerant flow path portion 71 is configured to communicate with the discharge-side refrigerant flow path portion 70. The downstream end portion of the first refrigerant flow path portion 71 is connected to the first valve 31.

[0028] A portion 71A of the first refrigerant flow path portion 71 is provided on the surface or inside of the stator core 21A, and constitutes a stator core cooling portion 71A. The refrigerant supplied from the first refrigerant flow path portion 71 cools the stator core 21A, that is, the stator 21 in the stator core cooling portion 71A.

[0029] The second refrigerant flow path portion 72 is a refrigerant flow path portion formed between the second valve 32 and the downstream end portions P41, 42, 43, 44 provided on the rotor 22. The upstream end portion P2 of the second refrigerant flow path portion 72 is connected to the second valve 32. The second valve 32 is provided between the branch point P1 and the branch point P2. The second refrigerant flow path portion 72 is connected to the discharge side refrigerant flow path portion 70 via the second valve 32, and is formed in a manner to communicate with the discharge side refrigerant flow path portion 70.

[0030] A portion 72A of the second refrigerant flow path portion 72 is provided inside the output shaft 23 and the rotor core 22A of the rotary electric machine 2, and constitutes the rotor cooling portion 72A. The refrigerant supplied by the second refrigerant flow path portion 72 cools the rotor 22 including the output shaft 23 and the rotor core 22A in the rotor cooling portion 72A. After the refrigerant supplied by the second refrigerant flow path portion 72 is supplied to the rotor cooling portion 72A and cools the rotor 22, it drips from the downstream side ends P41, 42, 43, and 44 of the second refrigerant flow path portion 72 to the coil end portion 21B as indicated by the reference numeral 81. The refrigerant 81 dripping onto the coil end portion 21B cools the coil end portion 21B and is stored in the housing 24 of the rotary electric machine 2. The refrigerant stored in the housing 24 is recovered to the refrigerant storage portion 5 from the discharge port 25 through a pipe (not shown).

[0031] The third refrigerant flow path portion 73 is a refrigerant flow path portion formed between the first valve 31 and the downstream side ends P31 and P32 provided near the stator 21. When the third refrigerant flow path portion 73 is connected to the first refrigerant flow path portion 71 via the first valve 31, the refrigerant supplied from the first refrigerant flow path portion 71 is guided to the downstream side ends (refrigerant dripping portions) P31 and P32, and drips from the downstream side ends P31 and P32 to the coil end portion 21B as shown by reference numeral 82. That is, the third refrigerant flow path portion 73 is provided between the first valve 31 and the refrigerant dripping portions P31 and P32 to the coil end portion 21B.

[0032] The fourth refrigerant flow path portion 74 is a refrigerant flow path portion formed between the first valve 31 and the upstream end portion (corresponding to the portion P2) of the second refrigerant flow path portion 72. The upstream end portion (corresponding to the portion P2) of the second refrigerant flow path portion 72 forms a branch point of the refrigerant flow path 7 connecting the second refrigerant flow path portion 72 and the fourth refrigerant flow path portion 74. The downstream end portion of the fourth refrigerant flow path portion 74 is connected to the upstream end portion of the second refrigerant flow path portion 72 at the branch point P2. In addition, the branch point P2 does not need to be set at the upstream end portion of the second refrigerant flow path portion 72, and can be set at a portion of the second refrigerant flow path portion 72 that is upstream of the rotor 22.

[0033] The switching mechanism 3 switches the connection states of the first refrigerant flow path 71, the second refrigerant flow path 72, the third refrigerant flow path 73, and the fourth refrigerant flow path 74. The switching mechanism 3 of this embodiment is composed of two valves including a first valve 31 and a second valve 32. In this case, the first valve 31 is composed of a three-way valve, and the second valve 32 is composed of an on-off valve. The first valve 31 and the second valve 32 of the switching mechanism 3 are opened and closed by the electronic control device 6 according to the vehicle speed or the rotation speed (rotation speed) of the rotary electric machine 2.

[0034] The electronic control unit (ECU) 6 is connected to the first valve 31 through a signal line E31 in order to control the first valve 31. The electronic control unit (ECU) 6 is connected to the second valve 32 through a signal line E32 in order to control the second valve 32.

[0035] Figure 5 It is for Figure 1 1, and an explanatory diagram showing the connection form of the refrigerant flow path 7 of the cooling system 1 of the rotating electrical machine 2. Figure 5 In the figure, (a) shows the connection form of the refrigerant flow path 7 in the low speed region, (b) shows the connection form of the refrigerant flow path 7 in the medium speed region, and (c) shows the connection form of the refrigerant flow path 7 in the high speed region.

[0036] The low speed region, the medium speed region, and the high speed region are defined as follows. The low speed region is a region in which the cooling of the rotating electrical machine 2 is achieved without cooling the rotor 22. The medium speed region is a region between the low speed region and the high speed region. The high speed region is a region in which the total amount of necessary refrigerant for the stator 21 and the rotor 22 is greater than the refrigerant discharge capacity limit (upper limit of the pump discharge amount) from the housing 2.

[0037] In the low speed region (a), the switching mechanism 3 realizes a first state in which refrigerant is supplied to the first refrigerant flow path 71 and refrigerant is not supplied to the second refrigerant flow path 72. In this case, the first valve 31 is driven to connect the first refrigerant flow path 71 with the third refrigerant flow path 73, and the second valve 32 is closed. By closing the second valve 32, the refrigerant discharge flow path 70 and the second refrigerant flow path 72 are blocked.

[0038] In the low speed region (a), the refrigerant cools the stator 21 in the stator core cooling portion 71A of the first refrigerant flow path portion 71, and is then supplied to the third refrigerant flow path portion 73 via the first valve 31, and flows from the downstream side ends P31 and P32 of the third refrigerant flow path portion 73 (see Figure 1 ) drips onto the coil end portion 21B. The refrigerant 82 (see Figure 1 ) is stored in the housing 24 of the rotary electric machine 2, and is recovered from the discharge port 25 to the refrigerant storage unit 5 through a pipe (not shown).

[0039] In the high speed region (c), the switching mechanism 3 realizes the second mode in which the downstream end of the first refrigerant flow path 71 is connected to the portion of the second refrigerant flow path 72 upstream of the rotor 22. In this case, the first valve 31 is driven to connect the first refrigerant flow path 71 to the third refrigerant flow path 73, and closes the second valve 32. By closing the second valve 32, the refrigerant discharge flow path 70 and the second refrigerant flow path 72 are blocked.

[0040] In the high speed region (c), after the refrigerant cools the stator 21 in the stator core cooling portion 71A of the first refrigerant flow path portion 71, it is not supplied to the third refrigerant flow path portion 73, but is supplied to the second refrigerant flow path portion 72 via the first valve 31. The refrigerant supplied from the first refrigerant flow path portion 71 to the second refrigerant flow path portion 72 cools the rotor 72 including the output shaft 23 in the rotor cooling portion 72A. Then, the refrigerant is supplied from the downstream side end portions P41, 42, 43, 44 (see Figure 1 ) drips onto the coil end 21B. The refrigerant 81 dripping onto the coil end 21B (see Figure 1 ) cools the coil end portion 21B and is stored in the housing 24 of the rotary electric machine 2. The refrigerant stored in the housing 24 is recovered from the discharge port 25 to the refrigerant storage unit 5 through a pipe (not shown).

[0041] In the intermediate region (b) between the low speed region (a) and the high speed region (c), the switching mechanism 3 realizes the third mode of supplying refrigerant to the first refrigerant flow path portion 71 and the second refrigerant flow path portion 72. In this case, the first valve 31 is driven to connect the first refrigerant flow path portion 71 and the third refrigerant flow path portion 73, and the second valve 32 is driven to open and connect the refrigerant discharge flow path portion 70 and the second refrigerant flow path portion 72.

[0042] In the medium speed region (b), the refrigerant is supplied from the refrigerant discharge flow path 70 to the first refrigerant flow path 71 and the second refrigerant flow path 72. That is, the refrigerant supplied from the refrigerant discharge flow path 70 is branched to the first refrigerant flow path 71 and the second refrigerant flow path 72 from the branch point P1.

[0043] The refrigerant supplied to the first refrigerant flow path portion 71 cools the stator 21 in the stator core cooling portion 71A, is supplied to the third refrigerant flow path portion 73 via the first valve 31, and drips from the third refrigerant flow path portion 73 to the coil end portion 21B. The refrigerant dripping to the coil end portion 21B is stored in the housing 24 of the rotary electric machine 2, and is recovered to the refrigerant storage portion 5 through the pipe from the discharge port 25. This is the same as the description in the low speed region of (a).

[0044] The refrigerant supplied to the second refrigerant flow path 72 cools the rotor 72 including the output shaft 23 in the rotor cooling portion 72A, and then drips onto the coil end portion 21B. The refrigerant 81 (see Figure 1 ) The cooling coil end portion 21B is stored in the housing 24 of the rotating electrical machine 2. The refrigerant stored in the housing 24 is recovered from the discharge port 25 through the pipe to the refrigerant storage unit 5. This is the same as the description in the high speed region of (c).

[0045] In the complex structure of the coil end 21B, the low-viscosity refrigerant spreads to the fine part of the coil end 21B, and the heat transfer coefficient from the coil end 21B to the refrigerant becomes high. Figure 5 In the connection form (c), the refrigerant heated by the stator core 21A drips or sprays to the coil end 21B, so the viscosity of the refrigerant dripping or spraying to the coil end 21B becomes low. Figure 5 The connection form (c) is not limited to the high-speed region, but can also be used in other speed regions, thereby improving the heat transfer rate from the coil end 21B to the refrigerant, thereby improving the cooling performance of the rotating electrical machine 2.

[0046] Next, a combination of normally open or normally closed of the first valve 31 and the second valve 32 used in the switching mechanism 3 will be described.

[0047] When the control of the first valve 31 and the second valve 32 fails, it is necessary to thermally protect the rotating electrical machine 2. Therefore, in order to ensure the cooling performance of the rotating electrical machine 2, a combination of the first valve 31 and the second valve 32 being normally open or normally closed is selected.

[0048] exist Figure 5 In the connection form (b), the first refrigerant flow path 71 for supplying refrigerant to the stator 21 and the second refrigerant flow path 72 for supplying refrigerant to the rotor 22 are connected in parallel, which is an ideal way to reliably supply refrigerant to the heating part. Therefore, it is preferred that the first valve 31 and the second valve 32 are both normally open valves. In addition, Figure 1 The diagram shows that normally open valves are used as the first valve 31 and the second valve 32 , and shows a state in which the first valve 31 and the second valve 32 are open when the power is not turned on.

[0049] The cooling system 1 of the rotating electrical machine 2 of the present embodiment is a cooling system 1 of the rotating electrical machine 2 including a stator 21 and a rotor 22. The refrigerant flow path 7 is provided with a refrigerant, a switching mechanism 3 for switching the state of the refrigerant flow path 7, and a pump 4 for pressurizing the refrigerant to the refrigerant flow path 7. The refrigerant flow path 7 includes a first refrigerant flow path portion 71 for supplying refrigerant to the core 21A of the stator 21 and a second refrigerant flow path portion 72 for supplying refrigerant to the rotor 22 . The switching mechanism 3 is configured to form a first state ( Figure 5 (a)), and a second form ( Figure 5 (c)).

[0050] In this case, in the second form ( Figure 5 In (c)), the first refrigerant flow path portion 71 and the second refrigerant flow path portion 72 are connected in series, and the refrigerant that has cooled the stator 21 is supplied to the rotor 22 to cool the rotor 22 .

[0051] Furthermore, in the cooling system 1 of the rotating electrical machine 2 of the present embodiment, The switching mechanism 3 is configured to form a third mode ( Figure 5 (b)).

[0052] In this case, in the third form ( Figure 5In (b)), the first refrigerant flow path portion 71 and the second refrigerant flow path portion 72 are connected in parallel with the rotary electric machine 2 , and the refrigerant for cooling the rotor 22 is supplied to the rotor 22 without passing through the flow path for supplying the refrigerant for cooling the stator 21 .

[0053] Furthermore, in the cooling system 1 of the rotating electrical machine 2 of the present embodiment, In the low speed region of the rotating electrical machine 2, the high speed region which is a speed region higher than the low speed region, and the medium speed region between the low speed region and the high speed region, First Form ( Figure 5 (a)) is constructed in the low speed range, and the second mode ( Figure 5 (c)) is constructed in the high-speed area, and the third method ( Figure 5 (b)) is constructed in the medium speed region.

[0054] Furthermore, in the cooling system 1 of the rotating electrical machine 2 of the present embodiment, The refrigerant flow path 7 includes a third refrigerant flow path portion 73 for supplying refrigerant to the coil end portion 21B of the stator 21, and a fourth refrigerant flow path portion 74 provided so that the downstream end portion communicates with the second refrigerant flow path portion 72. The switching mechanism 3 includes a first valve 31 and a second valve 32. The first valve 31 is capable of switching between a connection state in which the first refrigerant flow path portion 71 is connected to the third refrigerant flow path portion 73 and a connection state in which the first refrigerant flow path portion 71 is connected to the fourth refrigerant flow path portion 74. The second valve 32 is arranged between the second refrigerant flow path portion 72 and the pump 4, and is constructed to be able to switch between a connection state in which the second refrigerant flow path portion 72 is connected to the refrigerant discharge flow path 70 of the pump 4 without passing through the first refrigerant flow path portion 71 and a connection state in which the connection is cut off.

[0055] Figure 6 1 is a diagram showing the relationship between the vehicle speed and the coolant supply amount in the cooling system 1 for the rotating electrical machine 2 according to the present invention.

[0056] The electric pump 41 operates at a speed at which the refrigerant discharge amount combined with the mechanical pump 42 exceeds the refrigerant required for the stator 21 and the rotor 22. That is, the discharge amount of the electric pump 41 is controlled so that the sum of the discharge amount of the electric pump 41 and the mechanical pump 42 is the minimum required refrigerant amount (stator + rotor refrigerant required amount). In the low speed range, DC loss dominates, and most of the loss occurs in the stator 21. In the low speed range, by supplying refrigerant only to the stator 21, even a small pump can ensure the refrigerant amount required for cooling.

[0057] In the medium speed region, the power economy is improved by connecting the refrigerant flow paths (the first refrigerant flow path portion 71 and the second refrigerant flow path portion 72) in parallel. In order to minimize the torque loss of the mechanical pump 42 in the medium speed region where the driving frequency is the highest, the switching mechanism 3 is opened and closed in the medium speed region so that the refrigerant flow paths (the first refrigerant flow path portion 71 and the second refrigerant flow path portion 72) of the stator 21 and the rotor 22 are connected in parallel. By connecting the refrigerant flow paths in parallel, the pressure loss is reduced, so the loss of the mechanical pump 42 can be reduced.

[0058] In the high-speed region, the power economy is improved by the oil pressure control of the variable displacement mechanical pump 42. In the high-speed region, the discharge amount of the mechanical pump 42 exceeds the refrigerant discharge capacity (refrigerant discharge limit) of the housing 24, and friction is generated due to the refrigerant entering the gap of the rotating electric machine 2. Therefore, in the high-speed region, the discharge amount of the variable displacement mechanical pump 42 is limited to not exceed the refrigerant discharge capacity of the housing 24. At this time, when the discharge amount of the variable displacement mechanical pump 42 (≈ the refrigerant discharge capacity of the housing 24) is lower than the required amount of refrigerant of the stator 21 and the rotor 22, the switching mechanism 3 is opened and closed in such a manner that the refrigerant flow paths (the first refrigerant flow path portion 71 and the second refrigerant flow path portion 72) of the stator 21 and the rotor 22 are in series, so that cooling under the discharge amount of the variable displacement mechanical pump 42 (≈ the refrigerant discharge capacity of the housing 24) is achieved. That is, in the high-speed region, by connecting the refrigerant flow paths (the first refrigerant flow path portion 71 and the second refrigerant flow path portion 72) of the stator 21 and the rotor 22 in series, the amount of refrigerant required for cooling can be reduced compared to when connected in parallel, thereby achieving cooling performance within the refrigerant discharge capacity.

[0059] Figure 7 This is a schematic configuration diagram showing a modification example (fourth modification example: modification example 4) of the switching mechanism 3 of the cooling system 1 of the rotating electrical machine 2 according to the first embodiment of the present invention.

[0060] The switching mechanism 3 is not limited to the configuration of the first valve 31 and the first valve 32 of the first embodiment. For example, the first valve 31 shown in the first embodiment can be divided into two valves 311 and 312, and the switching mechanism 3 of this embodiment is composed of three valves. That is, the first valve 31 of this embodiment is composed of the third valve 311 and the fourth valve 312. The third valve 321 and the fourth valve 322 can be composed of on-off valves.

[0061] In this example, the downstream portion of the first refrigerant flow path portion 71 is branched into two branch flow paths 71A and 71B at a branch point P5. The first branch flow path portion 71A is connected to the third valve 311 in a manner of communicating with the third refrigerant flow path portion 73 via the third valve 311. The second branch flow path portion 71B is connected to the fourth valve 312 in a manner of communicating with the fourth refrigerant flow path portion 74 via the fourth valve 312.

[0062] That is, the cooling system 1 of the rotating electrical machine 2 of this example, The first valve 31 is composed of two valves: a third valve 311 and a fourth valve 312. The downstream portion of the first refrigerant flow path portion 71 is branched into a first branch flow path portion 71B connected to the third valve 311 and a second branch flow path portion 71C connected to the fourth valve. The third valve 311 is configured to open and close the connection between the first branch flow path portion 71B and the third refrigerant flow path portion 73 . The fourth valve 312 is configured to open and close the connection between the second branch flow path portion 71C and the second refrigerant flow path portion 72 .

[0063] like Figure 7 As shown, the electronic control unit (ECU) 6 is connected to the second valve 32 through a signal line E32 in order to control the second valve 32. The electronic control unit (ECU) 6 is connected to the third valve 311 through a signal line E311 in order to control the third valve 311. The electronic control unit (ECU) 6 is connected to the fourth valve 312 through a signal line E312 in order to control the fourth valve 312.

[0064] In this example, in order to thermally protect the rotating electrical machine 2 when the control of the third valve 311, the fourth valve 312 and the second valve 32 fails, it is preferred that the third valve 311 and the second valve 32 are normally open and the fourth valve 312 is normally closed. Figure 7 The diagram shows that the third valve 311 and the second valve 32 are normally open valves, and the fourth valve 312 is normally closed, indicating that when the power is not turned on, the first valve 31 and the second valve 32 are open, and the fourth valve 312 is closed.

[0065] From the perspective of cost, sometimes the same valve is used for all valves. In this case, the magnitude relationship of the pressure loss of each flow path under normal conditions can be determined so that cooling performance can be ensured when valve control fails. Figure 7 In the case where, for example, the third valve 311, the fourth valve 312 and the second valve 32 are all set to be normally open, the pressure loss design can be performed so that when all valves 311, 312, 32 are open, the refrigerant flows in a specific refrigerant path.

[0066] Figure 8 It is for Figure 7 A diagram showing the opening and closing states of valves in each speed range of a cooling system for a rotating electrical machine.

[0067] like Figure 8 As shown, the second valve 32 , the third valve 321 , and the fourth valve 322 are controlled by a control signal from the electronic control device 6 in accordance with the driving mode (vehicle speed range), and the connection form of the refrigerant flow path 7 is switched.

[0068] Fig. 9 This is a schematic configuration diagram showing a modification example (fifth modification example: modification example 5) of the switching mechanism 3 of the cooling system 1 of the rotating electrical machine 2 according to the first embodiment of the present invention.

[0069] exist Figure 7 In the switching mechanism 3, a part or all of the valves 32, 311, 312 may be formed as an integrated unit. Figure 1 The switching mechanism 3 is to Figure 7 This is an example in which the third valve 311 and the fourth valve 312 in the switching mechanism 3 are configured as an integrated unit (first valve 31).

[0070] exist Fig. 9 In Figure 7 All valves of the valves 32, 311, and 312 are configured as an integrated unit (valve unit 3). By integrating a plurality of valves into an integrated unit, the number of components can be reduced, and the assembly of the cooling system 1 becomes easy.

[0071] Fig.10 This is a diagram showing the relationship between the vehicle speed and the coolant supply amount when the operating range of the electric pump 41 is changed in the cooling system 1 for the rotating electrical machine 2 of the present invention.

[0072] When the discharge capacity of the mechanical pump 42 is sufficient, as shown in FIG. Fig.10 As shown, the working area of ​​the electric pump 41 can be reduced and the power economy can be improved. In this example, the working area of ​​the electric pump 41 is limited to a range in which the stator 21 is cooled only in the low speed area.

[0073] In addition, the present invention is not limited to the above-mentioned embodiments, and includes various modified examples. For example, the above-mentioned embodiments are detailed descriptions for easily understanding the present invention, and are not necessarily limited to having all the configurations. In addition, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of one embodiment can be added to the configuration of another embodiment. In addition, for a part of the configuration of each embodiment, other configurations can be added, deleted, or replaced. Explanation of symbols

[0074] 1…Cooling system of rotating electrical machine 2, 2…Rotating electrical machine, 3…Switching mechanism, 4…Pump, 7…Refrigerant flow path, 21…Stator, 21A…Core (stator core) of stator 21, 21B…Coil end of stator 21, 22…Rotor, 23…Output shaft of rotating electrical machine 2, 31…First valve, 32…Second valve, 41…Electric pump, 42…Mechanical pump, 70…Refrigerant discharge flow path of pump 4, 71…First refrigerant flow path portion, 71B…First branch flow path portion of first refrigerant flow path portion 71, 71C…Second branch flow path portion of first refrigerant flow path portion 71, 72…Second refrigerant flow path portion, 73…Third refrigerant flow path portion, 74…Fourth refrigerant flow path portion, 101…Reducer, 104…Drive shaft, 311…Third valve, 312…Fourth valve.

Claims

1. A cooling system for a rotating electrical machine, the rotating electrical machine comprising a stator and a rotor, wherein the cooling system is characterized in that: The cooling system comprises: a refrigerant flow path for supplying refrigerant; a switching mechanism for switching the form of the refrigerant flow path; and a pump for pressurizing the refrigerant to the refrigerant flow path. The refrigerant flow path includes: a first refrigerant flow path portion that supplies refrigerant to the core of the stator; and a second refrigerant flow path portion that supplies refrigerant to the rotor. The switching mechanism is configured to form a first state in which refrigerant is supplied to the first refrigerant flow path portion but not to the second refrigerant flow path portion, and a second state in which the downstream of the first refrigerant flow path portion communicates with the upstream of the second refrigerant flow path portion.

2. The cooling system for a rotating electrical machine according to claim 1, characterized in that: In the second aspect, the first refrigerant flow path portion and the second refrigerant flow path portion are connected in series, and the refrigerant that has cooled the stator is supplied to the rotor to cool the rotor.

3. The cooling system for a rotating electrical machine according to claim 2, characterized in that: The switching mechanism is configured to form a third mode in which the refrigerant is supplied to each of the first refrigerant flow path portion and the second refrigerant flow path portion.

4. The cooling system for a rotating electrical machine according to claim 3, characterized in that: In the third aspect, the first refrigerant flow path portion and the second refrigerant flow path portion are connected in parallel with the rotating electrical machine, and the refrigerant for cooling the rotor is supplied to the rotor through a flow path different from a flow path through which the refrigerant for cooling the stator passes.

5. The cooling system for a rotating electrical machine according to claim 4, characterized in that: In a low speed region of the rotating electrical machine, a high speed region higher than the low speed region, and a medium speed region between the low speed region and the high speed region, The first mode is configured in the low speed range, the second mode is configured in the high speed range, and the third mode is configured in the medium speed range.

6. The cooling system for a rotating electrical machine according to claim 5, characterized in that: The refrigerant flow path includes: a third refrigerant flow path portion for supplying refrigerant to the coil end portion of the stator; and a fourth refrigerant flow path portion whose downstream end portion is provided to communicate with the second refrigerant flow path portion. The switching mechanism includes a first valve and a second valve. The first valve is configured to switch between a connection state in which the first refrigerant flow path portion is connected to the third refrigerant flow path portion and a connection state in which the first refrigerant flow path portion is connected to the fourth refrigerant flow path portion. The second valve is arranged between the second refrigerant flow path portion and the pump, and is configured to be able to switch between a connection state in which the second refrigerant flow path portion is connected to the refrigerant discharge flow path of the pump without passing through the first refrigerant flow path portion and a connection state in which the connection is cut off.

7. The cooling system for a rotating electrical machine according to claim 6, characterized in that: The first valve is composed of two valves, a third valve and a fourth valve. The downstream portion of the first refrigerant flow path is divided into a first branch flow path connected to the third valve and a second branch flow path connected to the fourth valve. The third valve is configured to open and close the connection between the first branch flow path and the third refrigerant flow path. The fourth valve is configured to open and close the connection between the second branch flow path portion and the second refrigerant flow path portion.

8. The cooling system for a rotating electrical machine according to claim 7, characterized in that: The pump includes a mechanical pump and an electric pump. The mechanical pump obtains power from a shaft of a speed reducer provided between the rotary electric machine and a drive shaft.

9. The cooling system for a rotating electrical machine according to claim 7, characterized in that: The pump includes a mechanical pump and an electric pump. The mechanical pump obtains power from an output shaft of the rotating electric machine.

10. The cooling system for a rotating electrical machine according to claim 7, characterized in that: The pump includes a mechanical pump and an electric pump. The mechanical pump draws power from a drive shaft.

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