Drive unit for vehicle

Abstract

To appropriately regulate a flow direction of coolant while providing a gap between two water channel formation members in a configuration where a coolant passage is formed between the two water channel formation members.SOLUTION: A drive unit for a vehicle is disclosed, which comprises: a first flow channel formation member; a second flow channel formation member facing the first flow channel formation member to form a flow channel for coolant with the first flow channel formation member; and a third flow channel formation member with a thermal expansion coefficient higher than that of the second flow channel formation member, wherein the second flow channel formation member comprises a flow regulation part which regulates flow of the coolant on the flow channel, the flow regulation part projects toward the first flow channel formation member and faces the first flow channel formation member via a gap, and the third flow channel formation member is provided on an end surface facing the first flow channel formation member in the flow regulation part or the surface to which the flow regulation part in the first flow channel formation member faces.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present disclosure relates to a drive device for a vehicle.

Background Art

[0002] A technique for forming a refrigerant flow path (cooling water passage) between two water passage forming members provided around a rotating electric machine is known.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, when forming a refrigerant flow path between two water passage forming members, the flow direction of the refrigerant may be regulated so that the object to be cooled is cooled in a desired manner while the refrigerant enters from the inlet and exits from the outlet. At this time, a gap is often provided between the two water passage forming members due to assembly constraints or the like, and due to such a gap, the flow direction of the refrigerant may not be appropriately regulated.

[0005] Therefore, on one side, the present disclosure aims to appropriately regulate the flow direction of the refrigerant while providing a gap between two water passage forming members in a configuration where a refrigerant flow path is formed between the two water passage forming members.

Means for Solving the Problems

[0006] On one side, a first flow path forming member, a second flow path forming member facing the first flow path forming member and forming a flow path for the refrigerant between the first flow path forming member and the second flow path forming member, and a third flow path forming member having a higher coefficient of thermal expansion than the second flow path forming member. The second flow path forming member has a flow regulating portion that regulates the flow of the refrigerant in the flow path. The flow regulating portion protrudes toward the first flow path forming member and faces the first flow path forming member with a gap therebetween. The third flow path forming member is provided on an end face of the flow regulating portion facing the first flow path forming member or on a surface of the first flow path forming member facing the flow regulating portion, and a vehicle drive device is provided.

Advantages of the Invention

[0007] On one side, according to the present disclosure, in a configuration in which a refrigerant flow path is formed between two water channel forming members, it is possible to appropriately regulate the flow direction of the refrigerant while providing a gap between the two water channel forming members.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 2A

Figure 3

Figure 4

Figure 4A

Figure 5

Figure 6A

Figure 6B

Figure 6C

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Mode for Carrying Out the Invention

[0009] Hereinafter, each embodiment will be described in detail with reference to the accompanying drawings. Note that the dimensional ratios in the drawings are merely examples and are not limited thereto, and the shapes and the like in the drawings may be exaggerated partially for the convenience of explanation.

[0010] In the following description, the Y direction (see FIG. 3 etc.) corresponds to the vertical direction in the usage state of the vehicle drive device 100, that is, the vertical direction when the vehicle drive device 100 is arranged in its usage state orientation. And the Y1 side and the Y2 side correspond to the upper side and the lower side along the Y direction. Note that the vertical direction does not necessarily have to be parallel to the vertical direction, and it suffices to mainly have a vertical direction component. Also, the directions of the respective members in the following description represent the directions in the state where they are assembled to the vehicle drive device 100. Also, terms regarding the dimensions, arrangement directions, arrangement positions, etc. of the respective members are concepts including states having differences due to errors (errors allowable in manufacturing). The A direction (see FIG. 2 etc.) corresponds to the axial direction, and in FIG. 2 etc., the A1 side and the A2 side along the A direction are defined. Also, the X direction (see FIG. 3 etc.) is a direction orthogonal to both the A direction and the Y direction, and in FIG. 3 etc., the X1 side and the X2 side along the X direction are defined.

[0011] In this specification, "driving connection" refers to a state in which two rotating elements are connected so as to be able to transmit a driving force (synonymous with torque), including a state in which the two rotating elements are connected so as to rotate integrally, or a state in which the two rotating elements are connected so as to be able to transmit a driving force via one or more transmission members. Such transmission members include various members that transmit rotation at the same speed or with speed change (for example, shafts, gear mechanisms, belts, chains, etc.). Note that the transmission members may include engagement devices (for example, friction engagement devices, meshing engagement devices, etc.) that selectively transmit rotation and driving force.

[0012] In addition, in this specification, "communication" refers to a state in which two spatial elements are in fluid communication with each other. That is, it refers to a state in which fluid can flow back and forth between two spatial elements. At this time, the two spatial elements may communicate directly or indirectly (that is, via other spatial elements).

[0013] In this specification, "rotating electrical machine" is used as a concept that includes any of a motor (electric motor), a generator (generator), and a motor-generator that performs the functions of both a motor and a generator as required. In addition, in this specification, regarding the arrangement of two members, "overlapping in a specific direction view" means that when a virtual straight line parallel to the line-of-sight direction is moved in each direction orthogonal to the virtual straight line, there is at least a part of a region where the virtual straight line intersects both of the two members. In addition, in this specification, regarding the arrangement of two members, "the arrangement regions in a specific direction overlap" means that at least a part of the arrangement region of the other member in a specific direction is included within the arrangement region of one member in a specific direction.

[0014] FIG. 1 is a schematic top view showing the mounting state of the vehicle drive device 100 in the vehicle VC. FIG. 2 is a cross-sectional view of the vehicle drive device 100. FIG. 2A is a skeleton view showing the vehicle drive device 100.

[0015] As schematically shown in Fig. 2A, the vehicle drive device 100 includes a rotary electric machine 1, a pair of output members 6 respectively drivingly connected to a pair of wheels W (see Fig. 1), and a transmission mechanism 3 that transmits a driving force between the rotary electric machine 1 and the pair of output members 6. The vehicle drive device 100 further includes a case 2 that houses the rotary electric machine 1. The case 2 is formed of aluminum or the like and also houses the pair of output members 6 and the transmission mechanism 3. In a modified example, the case 2 may house only one of the pair of output members 6. Further, the application of the vehicle drive device 100 is applicable to any vehicle having a rotary electric machine 1, such as an electric vehicle or a hybrid vehicle, and the drive system is also applicable to any vehicle such as front-wheel drive or rear-wheel drive. Also, the drive source may be only an engine (internal combustion engine).

[0016] One of the pair of output members 6, the first output member 61, is drivingly connected to the first wheel W1, which is one of the pair of wheels W, and the other of the pair of output members 6, the second output member 62, is drivingly connected to the second wheel W2, which is the other of the pair of wheels W. As shown in Fig. 1, the vehicle VC on which the vehicle drive device 100 is mounted includes a first drive shaft 63 that rotates integrally with the first wheel W1 and a second drive shaft 64 that rotates integrally with the second wheel W2. The first drive shaft 63 is connected to the first wheel W1 via, for example, a constant velocity joint, and the second drive shaft 64 is connected to the second wheel W2 via, for example, a constant velocity joint. Then, the first output member 61 is connected to the first drive shaft 63 so as to rotate integrally with the first drive shaft 63, and the second output member 62 is connected to the second drive shaft 64 so as to rotate integrally with the second drive shaft 64. Note that the first output member 61 may be in the form of an intermediate shaft.

[0017] The vehicle drive device 100 transmits the output torque of the rotating electric machine 1 to a pair of wheels W via a pair of output members 6, causing the vehicle VC equipped with the vehicle drive device 100 to travel. That is, the rotating electric machine 1 is the driving force source for the pair of wheels W. The pair of wheels W are a pair of left and right wheels on the vehicle VC (for example, a pair of left and right front wheels or a pair of left and right rear wheels). The rotating electric machine 1 may be, for example, an AC rotating electric machine driven by three-phase AC.

[0018] As shown in FIG. 2, the rotating electric machine 1 and the pair of output members 6 are arranged separately on two axes (specifically, the first axis C1 and the second axis C2) parallel to each other. Specifically, the rotating electric machine 1 is arranged on the first axis C1, and the pair of output members 6 are arranged on a second axis C2 different from the first axis C1. The first axis C1 and the second axis C2 are axes (virtual axes) arranged parallel to each other. The transmission mechanism 3 includes an output gear (ring gear) 30 drivingly connected to at least one of the pair of output members 6, coaxially with the pair of output members 6 (that is, on the second axis C2).

[0019] The rotating electric machine 1 is, for example, of the inner rotor type. Inside the radial direction of the stator 11 (see FIG. 2), a rotor 14 rotatable about the first axis C1 is arranged.

[0020] The transmission mechanism 3 includes a speed reduction mechanism 34 in the power transmission path between the rotating electric machine 1 and the output gear 30. The speed reduction mechanism 34 is optional and may include a speed reduction mechanism using counter gears, a speed reduction mechanism using planetary gears, etc. In this embodiment, as an example, the speed reduction mechanism 34 includes a planetary gear mechanism, and the speed reduction mechanism 34 is arranged coaxially with the rotating electric machine 1. The output gear (carrier) 342 of the speed reduction mechanism 34 meshes radially with the output gear 30 of the differential gear mechanism 5. Such a vehicle drive device 100 can have a compact configuration consisting of two axes (the first axis C1 and the second axis C2). In a modification, the vehicle drive device 100 may have three or more axes.

[0021] In this embodiment, the speed reduction mechanism 34 is arranged coaxially with the rotary electric machine 1 (i.e., on the first axis C1) in a manner of being drivingly connected to the rotary electric machine 1. In this embodiment, as an example, the rotor 14 of the rotary electric machine 1 rotates integrally with the input member 16 together with the sun gear 341 of the speed reduction mechanism 34.

[0022] Further, the transmission mechanism 3 further includes a differential gear mechanism 5. The differential gear mechanism 5 distributes the driving force transmitted from the side of the rotary electric machine 1 to a pair of output members 6. In the example shown in FIG. 2, the differential gear mechanism 5 distributes the rotation of the output gear 30 to the first side gear 51 and the second side gear 52. The differential gear mechanism 5 may be arranged coaxially with a pair of output members 6 (i.e., on the second axis C2). Note that the differential gear mechanism 5 may be a bevel gear type differential gear mechanism, and the output gear 30 may be connected to the differential case portion 50 provided in the differential gear mechanism 5 so as to rotate integrally with the differential case portion 50.

[0023] Next, with reference to FIGS. 3 and later, the water cooling structure of the rotary electric machine 1 according to this embodiment and related components (such as the flow path forming member 90) will be described.

[0024] FIG. 3 is a side view schematically showing the vehicle drive device 100 according to this embodiment. In FIG. 3, the illustration of the motor cover member 201 is omitted so as to show the state inside the motor housing chamber S1. Also, in FIG. 3, the inverter device 70 inside the inverter case portion 24 is schematically shown by a dotted line. FIG. 4 is a perspective view of the flow path forming member 90. In FIG. 4 (similarly in FIG. 5), the positions of the inlet portion 95 and the outlet portion 96 with respect to the refrigerant flow path 300 are schematically shown by a projection view (a circular dashed line). FIG. 4A is an enlarged view of the Q4 portion of FIG. 4. FIG. 5 is a schematic view of the refrigerant flow path 300 formed by the flow path forming member 90, and is an explanatory view in which the outer peripheral surface of the flow path forming member 90 is developed on a plane. FIG. 6A is a cross-sectional view of a part of the refrigerant flow path 300 (the portion along the line A-A in FIG. 5). FIG. 6B is a side view schematically showing the positional relationship between the first output member 61 and the refrigerant supply portion 40 and the refrigerant discharge portion 42. FIG. 6C is an enlarged view of the Q6 portion of FIG. 2.

[0025] The water cooling structure of the rotating electrical machine 1 according to this embodiment is a structure for cooling the rotating electrical machine 1 with cooling water. The cooling water may be, for example, water containing LLC (Long Life Coolant), and may be circulated by a water pump (not shown). A heat radiating part such as a radiator (not shown) may be provided in the circulation path of the cooling water. Further, the cooling water may be used not only for cooling the rotating electrical machine 1 but also for cooling other components, for example, an inverter device 70 electrically connected to the rotating electrical machine 1.

[0026] As shown in FIG. 4, the water cooling structure of the rotating electrical machine 1 according to this embodiment may include a refrigerant supply part 40, a refrigerant discharge part 42, and a flow path forming member 90.

[0027] The refrigerant supply part 40 communicates, for example, with the discharge side of a water pump (not shown), and supplies cooling water to a refrigerant flow path 300 (described later) formed by the flow path forming member 90.

[0028] The refrigerant discharge part 42 communicates, for example, with the suction side of a water pump (not shown), and supplies (discharges) the cooling water from the refrigerant flow path 300 (described later) formed by the flow path forming member 90 to the water pump (not shown).

[0029] As shown in FIG. 6B, the refrigerant supply part 40 and the refrigerant discharge part 42 may be respectively provided on the upper and lower sides with the first output member 61 interposed therebetween. In this case, the space around the first output member 61 can be effectively utilized to form the refrigerant supply part 40 and the refrigerant discharge part 42.

[0030] As shown in FIG. 4, the flow path forming member 90 has a cylindrical form having an inner peripheral surface facing the outer peripheral surface of the rotating electrical machine 1 in the radial direction. The flow path forming member 90 forms a refrigerant flow path 300 around the rotating electrical machine 1.

[0031] The flow path forming member 90 may be formed of a material with good thermal conductivity, such as aluminum. In this embodiment, as an example, the flow path forming member 90 is fitted to the stator core 12 of the stator 11, for example, by shrink fitting. Thereby, the adhesion (interference fit) between the flow path forming member 90 and the stator core 12 can be enhanced, and the thermal resistance between the flow path forming member 90 and the stator core 12 can be reduced. In other embodiments, the flow path forming member 90 may be integrally formed with the stator core 12 by casting or the like. Further, the flow path forming member 90 may be formed as a part of the case 2.

[0032] In this embodiment, as an example, the flow path forming member 90 is in the form of an inner case fastened to the case 2, as shown in FIG. 3. In this case, the flow path forming member 90 has a plurality of fastening portions 500 at one end side in the axial direction, as shown in FIG. 3. A preferred example of the arrangement of the plurality of fastening portions 500 will be described later.

[0033] The flow path forming member 90 is inserted into the cylindrical space portion (motor housing chamber S1) of the case 2. At this time, the outer peripheral surface of the flow path forming member 90 faces the inner peripheral surface (the inner peripheral surface that bounds the plurality of fastening portions 500) of the motor case portion 21 (see FIG. 2) of the case 2 in the radial direction. Hereinafter, the inner peripheral surface of the case 2 that surrounds the flow path forming member 90 in this way is also referred to as the "flow path forming surface 209 of the case 2". The inner diameter of the flow path forming surface 209 of the case 2 may be a constant value that is larger than the basic outer diameter of the stator core 12 by the basic wall thickness t0 (see FIG. 6A) of the flow path forming member 90.

[0034] The flow path forming member 90 cooperates with the flow path forming surface 209 of the case 2 to form the refrigerant flow path 300. Specifically, the refrigerant flow path 300 is formed between the outer peripheral surface of the flow path forming member 90 and the flow path forming surface 209 of the case 2 in the radial direction.

[0035] The refrigerant flow path 300 may extend in the circumferential direction so that the cooling water flows in the circumferential direction over the entire circumferential direction. Further, the refrigerant flow path 300 may be formed to face the outer peripheral surface of the stator core 12 in the radial direction over the entire axial direction of the stator core 12 of the rotating electric machine 1. Note that the refrigerant flow path 300 is closed at both axial ends. For example, a sealing member 97 (see FIG. 6C) may be provided over the entire circumferential direction at both axial ends of the flow path forming member 90 between the flow path forming member 90 and the flow path forming surface 209 of the case 2.

[0036] In the present embodiment, as shown in FIGS. 3 and 4, the refrigerant flow path 300 broadly includes a first circumferential section SC1, a second circumferential section SC2, a third circumferential section SC3, and a fourth circumferential section SC4.

[0037] The first circumferential section SC1 is a section including the inlet portion 95. The refrigerant supply portion 40 is connected to the inlet portion 95. Accordingly, the cooling water is introduced into the refrigerant flow path 300 from the inlet portion 95. Note that the inlet portion 95 may be in the form of an opening at the end of the refrigerant supply portion 40.

[0038] The second circumferential section SC2 is a section including the outlet portion 96. The refrigerant discharge portion 42 is connected to the outlet portion 96. Accordingly, the cooling water introduced into the refrigerant flow path 300 is discharged to the outside of the refrigerant flow path 300 through the outlet portion 96. Note that the outlet portion 96 may be in the form of an opening at the end of the refrigerant discharge portion 42.

[0039] The third circumferential direction section SC3 may extend between the first circumferential direction section SC1 and the second circumferential direction section SC2 in the circumferential direction and may be the section with the longest circumferential length. The flow path forming member 90 has a convex portion 91 that protrudes radially in a manner of reducing the cross-sectional area of the refrigerant flow path 300 in the third circumferential direction section SC3. In the present embodiment, the convex portion 91 is in the form of a convex strip or rib that continuously extends in the circumferential direction and is formed in a manner of arranging a plurality of them in the axial direction. However, in other embodiments, the convex portion 91 may be realized in other forms and other arrangements. For example, convex portions in the form of cylinders may be arranged in a staggered manner. The upper surface (the radially outer surface) of the convex portion 91 may be in radial contact with the flow path forming surface 209 of the case 2, or may be slightly spaced apart from the flow path forming surface 209 of the case 2. In either case, the portion of the third circumferential direction section SC3 in the refrigerant flow path 300 is mainly formed by the portion where the convex portion 91 is not formed.

[0040] The fourth circumferential direction section SC4 may extend between the first circumferential direction section SC1 and the second circumferential direction section SC2 in the circumferential direction and may be a section with a significantly shorter circumferential length than the third circumferential direction section SC3. The flow path forming member 90 may not have a convex portion such as the convex portion 91 in the fourth circumferential direction section SC4. In the present embodiment, the flow path forming member 90 has a basically flat surface (outer peripheral surface) in the fourth circumferential direction section SC4.

[0041] In the present embodiment, when cooling water is introduced into the inlet portion 95 of the refrigerant flow path 300, it flows axially in the first circumferential direction section SC1 (see arrow R52 in FIG. 5) and is distributed to the third circumferential direction section SC3 and the fourth circumferential direction section SC4 (see arrows R51 and R53 in FIG. 5). Then, the cooling water flowing in the circumferential direction in the third circumferential direction section SC3 (see arrows R51 and R55 in FIG. 5) flows axially (see arrow R54 in FIG. 5) when reaching the second circumferential direction section SC2 and is discharged from the outlet portion 96. Also, the cooling water flowing in the circumferential direction (which may also have an axial component) in the fourth circumferential direction section SC4 (see arrow R53 in FIG. 5) flows axially (see arrow R54 in FIG. 5) when reaching the second circumferential direction section SC2 and is discharged from the outlet portion 96.

[0042] Incidentally, generally, a fluid tends to flow through a flow path with less resistance. In this regard, the third circumferential direction section SC3 has a resistance element such as the convex portion 91. Therefore, if there is a flow path portion between the inlet portion 95 and the outlet portion 96 that has significantly less resistance than the third circumferential direction section SC3, there is a possibility that the cooling water may not flow sufficiently through the third circumferential direction section SC3. In this case, there is a risk that the cooling (cooling by the cooling water) of the portion of the entire stator core 12 that radially faces the third circumferential direction section SC3 may be insufficient. In particular, when the resistance of the flow path portion via the fourth circumferential direction section SC4 from the inlet portion 95 to the outlet portion 96 is significantly smaller than the relationship in the present embodiment as described later, there is a risk that the cooling (cooling by the cooling water) of the portion of the entire stator core 12 that radially faces the third circumferential direction section SC3 may be insufficient.

[0043] Therefore, in the present embodiment, the flow path structure in the fourth circumferential direction section SC4 may be adapted so that the pipe loss coefficient in the fourth circumferential direction section SC4 is equal to the pipe loss coefficient in the third circumferential direction section SC3. The pipe loss coefficient may be evaluated as pipe loss coefficient = (pressure loss) / (flow rate)α, where α > 1. Alternatively, from the same perspective, the flow path structure in the fourth circumferential direction section SC4 may be adapted so that the flow rate in the fourth circumferential direction section SC4 is equal to the flow rate in the third circumferential direction section SC3. Thereby, the flow rate of the cooling water flowing through the refrigerant flow path 300 (and the associated cooling capacity) can be made uniform over the circumferential direction.

[0044] However, the flow rate in the fourth circumferential direction section SC4 and the flow rate in the third circumferential direction section SC3 may correspond to the ratio of the circumferential length of the fourth circumferential direction section SC4 to the circumferential length of the third circumferential direction section SC3. This is because the longer the circumferential length, the more useful a high cooling capacity becomes.

[0045] In this embodiment, the maximum value of the radial width of the cross-section of the refrigerant flow path 300 is the smallest in the fourth circumferential section SC4 among the first circumferential section SC1 to the fourth circumferential section SC4, and the largest in the third circumferential section SC3. Thereby, since the resistance in the fourth circumferential section SC4 can be made relatively large, an appropriate flow rate of the cooling water flowing through the third circumferential section SC3 can be ensured. In this embodiment, since the convex portion 91 is provided in the third circumferential section SC3, the maximum value of the radial width of the cross-section of the refrigerant flow path 300 in the third circumferential section SC3 occurs at a portion without the convex portion 91.

[0046] Also, in this embodiment, when the maximum value of the radial width of the cross-section of the refrigerant flow path 300 is set to h1 to h4 (see FIG. 6A, however, h2 is not shown) in each of the first circumferential section SC1 to the fourth circumferential section SC4, it has the relationship of h4 < h1 < h3 and h4 < h2 < h3. At this time, h1 may be equal to h2, or h1 may be approximately equal to h2. Further, for the fourth circumferential section SC4, the maximum value of the radial width of the cross-section of the refrigerant flow path 300 corresponds to the radial width of the portion excluding the convex portion 91 (that is, the radial width of the groove portion 92 adjacent to the convex portion 91).

[0047] In this embodiment, as described above, the flow path forming member 90 is disposed between the stator core 12 and the flow path forming surface 209 of the case 2, and the radial distance between the stator core 12 and the flow path forming surface 209 of the case 2 is substantially constant over the entire circumferential direction (i.e., a constant value corresponding to the basic wall thickness t0). Therefore, in this embodiment, the relationships of h4 < h1 < h3 and h4 < h2 < h3 described above can be realized by changing the wall thickness of the flow path forming member 90. In this case, when the minimum value of the radial wall thickness of the portion forming the refrigerant flow path 300 in the flow path forming member 90 is t1 to t4 in each of the first circumferential section SC1 to the fourth circumferential section SC4, it has the relationships of t4 > t1 > t3 and t4 > t2 > t3. Alternatively, in other words, for the fourth circumferential section SC4, when the wall thickness of the portion excluding the convex portion 91 is t4, it has the relationships of t4 > t1 > t3 and t4 > t2 > t3. At this time, t1 = t2 may be satisfied, or t1 ≈ t2 may be satisfied. For example, t1 = (t4 + t3) / 2 may be satisfied.

[0048] Note that the portion forming the refrigerant flow path 300 in the flow path forming member 90 is substantially the portion through which the refrigerant passes. For example, it may be a portion in the range radially facing the stator core 12, or may be a portion in the axial range between the inlet portion 95 and the outlet portion 96.

[0049] Here, as in this embodiment, when there is a relatively large difference in wall thickness in the flow path forming member 90, stress concentration is likely to occur due to the difference. In particular, in this embodiment, since the flow path forming member 90 is shrink-fitted, stress concentration during shrink-fitting is likely to be a problem. Further, since the flow path forming member 90 can thermally contract due to the heat from the stator core 12 or the influence of the cooling water, thermal stress is likely to occur.

[0050] In contrast, in this embodiment, although there is a relatively large difference in wall thickness (= t4 - t3) in the flow path forming member 90 between the fourth circumferential direction section SC4 and the third circumferential direction section SC3, the first circumferential direction section SC1 and the second circumferential direction section SC2 can alleviate the difference in wall thickness. Specifically, between the fourth circumferential direction section SC4 and the third circumferential direction section SC3, there are the first circumferential direction section SC1 and the second circumferential direction section SC2 having an intermediate wall thickness therebetween. In this way, in this embodiment, the flow path forming member 90 can alleviate the difference in wall thickness (= t4 - t3) between the fourth circumferential direction section SC4 and the third circumferential direction section SC3 in the first circumferential direction section SC1 and the second circumferential direction section SC2. As a result, the problem of stress that may occur due to the relatively large difference in wall thickness in the flow path forming member 90 can be reduced or eliminated.

[0051] Here, further, as in this embodiment, since the convex portion 91 in the flow path forming member 90 similarly causes a difference in wall thickness, stress concentration is likely to occur at the edge (extreme) of the convex portion 91 or the like. In this regard, if the circumferential end position of the convex portion 91 is set at the boundary between the third circumferential direction section SC3 and the first circumferential direction section SC1 and the second circumferential direction section SC2, stress concentration is likely to occur at the boundary. That is, in this case, at the boundary, the stress caused by the difference in wall thickness (= t1 or t2 - t3) between the third circumferential direction section SC3 and the first circumferential direction section SC1 and the second circumferential direction section SC2 and the stress caused by the generation of the convex portion 91 are likely to occur simultaneously.

[0052] Therefore, in this embodiment, the convex portion 91 preferably terminates in the first circumferential direction section SC1 and the second circumferential direction section SC2 as shown in FIGS. 4 and 5. That is, the convex portion 91 in the third circumferential direction section SC3 preferably extends continuously to a part of the first circumferential direction section SC1 on the side connected to the third circumferential direction section and a part of the second circumferential direction section SC2 on the side connected to the third circumferential direction section SC3. Thereby, the stress concentration that may occur at the boundary between the third circumferential direction section SC3 and the first circumferential direction section SC1 and the second circumferential direction section SC2 can be reduced.

[0053] In this embodiment, the fourth circumferential direction section SC4 of the flow path forming member 90 is arranged to intersect a straight line (not shown) connecting the axis (second axis C2) of the first output member 61 and the axis (first axis C1) of the rotating electric machine 1 when viewed in the axial direction. As a result, as described above, the refrigerant supply section 40 and the refrigerant discharge section 42 can be arranged above and below with the axis (second axis C2) of the first output member 61 interposed therebetween, and the space that could be a dead space can be efficiently utilized.

[0054] Next, with reference to FIG. 7 and subsequent figures, further details of the flow path structure according to this embodiment will be described. Note that the flow path structure 900 (or its various modifications, the same applies hereinafter) described below is preferably realized using the above-described flow path forming member 90 and the case 2. However, it is also possible to realize the above-described flow path forming member 90 and the case 2 using a flow path forming member and / or a case having a different configuration. For example, the flow path structure 900 described below can also be realized using a flow path forming member 90 that does not have the characteristics regarding the wall thickness of the flow path forming member 90 as described above. For example, the fourth circumferential direction section SC4 may be omitted, and the flow such as the arrow R53 may be blocked by a seal member such as the seal member 97. Further, a convex portion 91 may also be provided in the fourth circumferential direction section SC4. In this case, the inlet portion 95 and the outlet portion 96 may be arranged at circumferentially diagonal positions.

[0055] FIG. 7 is a schematic cross-sectional view of the flow path structure 900 according to this embodiment, and is a cross-sectional view corresponding to an enlarged view of the Q7 portion in FIG. 6C.

[0056] In this embodiment, as shown in FIG. 7, the case 2 and the flow path forming member 90 face each other in the radial direction with a radial gap Δ1 therebetween. Note that the flow path forming member 90 is fixed in a manner having a radial interference fit with the stator core 12 by shrink fitting as described above.

[0057] Note that the radial gap Δ1 may strictly have slightly different values at each position (for example, one circumferential position and another circumferential position) between the case 2 and the flow path forming member 90, but in this embodiment, it is assumed to be constant for the sake of explanation.

[0058] In this embodiment, a gap adjusting member 98 is provided on the convex portion 91 of the flow path forming member 90. The gap adjusting member 98 is provided on the end surface on the outer side in the radial direction of the convex portion 91. That is, the gap adjusting member 98 is abutted against the outer side in the radial direction of the convex portion 91 in a manner of increasing the height (dimension in the radial direction) of the convex portion 91. Note that the gap adjusting member 98 may be integrated with the convex portion 91 by adhesion, or may be integrated during the molding of the flow path forming member 90.

[0059] The gap adjusting member 98 is provided over the entire circumferential direction of the convex portion 91, but may be provided only on a part of the entire circumferential direction of the convex portion 91.

[0060] The gap adjusting member 98 has a higher coefficient of thermal expansion than the case 2 and the flow path forming member 90. For example, when the case 2 and the flow path forming member 90 are formed of aluminum, the gap adjusting member 98 may be formed of a material different from aluminum and having a higher coefficient of thermal expansion than aluminum. The gap adjusting member 98 may be formed of, for example, a resin material.

[0061] In this embodiment, since the gap adjusting member 98 is provided on the convex portion 91 of the flow path forming member 90, the radial gap Δ0 between the flow path forming member 90 provided with the gap adjusting member 98 and the case 2 is Δ0 = Δ1 - d1, where d1 is the dimension in the radial direction of the gap adjusting member 98.

[0062] In this embodiment, since the gap adjusting member 98 has a higher coefficient of thermal expansion than the case 2 and the flow path forming member 90, Δ0 = Δ1 - d1 changes depending on the temperature. Here, Δ0 at a certain reference temperature (for example, normal temperature within the temperature range during the assembly process) is also referred to as "nominal clearance Δ0".

[0063] The nominal clearance Δ0 is set due to assembly constraints between the case 2 and the flow path forming member 90. That is, the nominal clearance Δ0 is set (adapted) so as to absorb the dimensional error in the radial direction of the flow path forming member 90 (error within the allowable tolerance) and the dimensional error in the radial direction of the case 2 (error within the allowable tolerance). Further, since the flow path forming member 90 is deformed radially outward by shrink fitting, the nominal clearance Δ0 is set in consideration of such deformation.

[0064] Here, while contrasting with the comparative example shown in FIG. 8, the effects of this embodiment will be described with reference to FIGS. 9 to 11.

[0065] FIG. 8 is an explanatory diagram of a comparative example and is a diagram contrasted with the above-mentioned FIG. 7. FIG. 9 is an explanatory diagram of cooling water flowing radially across the convex portion 91 due to a gap and is the same as the above-mentioned FIG. 5. FIG. 10 is a diagram schematically showing the state of the flow path structure 900 when the temperature of the cooling water is high in this embodiment, and FIG. 11 is a diagram schematically showing the state of the flow path structure 900 when the temperature of the cooling water is low in this embodiment. In FIGS. 10 and 11, the flow direction of the cooling water is schematically shown by the directions of the arrows R51A and R51B, and the flow rate of the cooling water is schematically shown by the thickness of the arrows R51A and R51B (the thicker the arrow, the larger the related flow rate).

[0066] The flow path structure 900' according to the comparative example shown in FIG. 8 is different from the flow path structure 900 according to this embodiment in that the gap adjusting member 98 is omitted and the convex portion 91 is replaced with the convex portion 91'. The convex portion 91' according to the comparative example has a different gap from the case 2 compared to the convex portion 91 according to this embodiment and has a radial gap Δ1'. That is, in the comparative example, the case 2 and the flow path forming member 90' face each other radially with a radial gap Δ1' therebetween. The radial gap Δ1' may be equivalent to the above-mentioned nominal clearance Δ0.

[0067] The convex portion 91 (the same applies to the convex portion 91') functions as a flow regulating portion that regulates the flow of the refrigerant in the flow path. That is, at the position where the convex portion 91 is provided, the radial width of the cross-section of the refrigerant flow path 300 is smaller than at the position where the convex portion 91 is not provided, so the flow of the cooling water flowing radially across the convex portion 91 is suppressed. That is, the convex portion 91 has a function of promoting the circumferential flow as shown by the arrow R51 and the arrow R55 in the third circumferential direction section SC3 described above with reference to FIG. 5.

[0068] If there is a gap between the convex portion 91 (the same applies to the convex portion 91') and the case 2, the function of the convex portion 91 (the same applies to the convex portion 91') deteriorates compared to the case where there is no gap. That is, if there is a gap between the convex portion 91 (the same applies to the convex portion 91') and the case 2, the flow of the cooling water flowing radially across the convex portion 91 is likely to occur (see the arrow R51' and the arrow R55' in FIG. 9). This is particularly prominent when the radial positions of the inlet portion 95 and the outlet portion 96 are different as shown in FIG. 5. Also, the larger the dimension of the gap (radial dimension) between the convex portion 91 (the same applies to the convex portion 91') and the case 2, the more likely the flow of the cooling water flowing radially across the convex portion 91 is to occur.

[0069] In this regard, in the comparative example, since the materials of the case 2 and the flow path forming member 90' are the same (for example, aluminum), the radial gap Δ1' does not substantially change even when the temperature changes. Therefore, in the comparative example, the radial gap Δ1' does not substantially change even when the temperature of the cooling water changes.

[0070] On the other hand, according to the present embodiment, since the gap adjusting member 98 is provided on the convex portion 91 as described above, when the temperature of the cooling water changes, the radial gap Δ0 changes significantly.

[0071] Specifically, in this embodiment, when the temperature of the cooling water is significantly higher than the reference temperature (an example of the second temperature), the gap adjusting member 98 expands significantly more in the radial direction than the case 2 and the flow path forming member 90. That is, based on the time when the temperature of the cooling water is the reference temperature, the increase amount of the radial dimension of the gap adjusting member 98 is significantly larger than the increase amount (expansion amount) of the radial dimension of the case 2 and the flow path forming member 90. Therefore, at a high temperature where the temperature of the cooling water is significantly higher than the reference temperature, the radial gap Δ0 becomes smaller than the nominal clearance Δ0. When the radial gap Δ0 becomes smaller, it becomes difficult for the cooling water to flow radially across the convex portion 91 (see arrow R51A in FIG. 10). That is, in the third circumferential direction section SC3 described above with reference to FIG. 5, the circumferential flow as shown by arrow R51 and arrow R55 is promoted. As a result, the cooling of the stator core 12 can be made uniform along the axial direction and the circumferential direction. Local overheating of the stator core 12 can be appropriately prevented.

[0072] Also, in this embodiment, when the temperature of the cooling water is significantly lower than the reference temperature (an example of the first temperature), the gap adjusting member 98 contracts significantly more in the radial direction than the case 2 and the flow path forming member 90. That is, based on the time when the temperature of the cooling water is the reference temperature, the amount of decrease in the radial dimension of the gap adjusting member 98 is significantly larger than the amount of decrease (contraction amount) in the radial dimension of the case 2 and the flow path forming member 90. Therefore, at a low temperature where the temperature of the cooling water is significantly lower than the reference temperature, the radial gap Δ0 becomes larger than the nominal clearance Δ0. When the radial gap Δ0 becomes larger, a flow of cooling water flowing in the radial direction across the convex portion 91 is likely to occur (see arrow R51B in FIG. 11). In other words, this means that the cross-sectional area of the refrigerant flow path 300 increases and the pressure loss from the inlet portion 95 to the outlet portion 96 substantially decreases, based on the time when the temperature of the cooling water is the reference temperature. A situation where the temperature of the cooling water is significantly lower than the reference temperature corresponds to a situation where the need to cool the stator core 12 is relatively low. Therefore, under such a situation, since an efficient flow of cooling water can be prioritized, the energy efficiency can be increased. Also, by reducing the pressure loss of the refrigerant flow path 300, which becomes a constraint at low temperatures when the viscosity of the cooling water increases, it is possible to eliminate the need for high pump performance (the performance of a water pump (not shown)).

[0073] Thus, according to this embodiment, in a configuration in which the refrigerant flow path 300 is formed between two water path forming members, that is, the case 2 and the flow path forming member 90, while providing a gap Δ1 between the two water path forming members, the flow direction of the refrigerant (cooling water) can be appropriately regulated.

[0074] Next, with reference to FIGS. 12 and 13, a modification of the flow path structure 900 according to the above-described embodiment will be outlined.

[0075] FIG. 12 is an explanatory diagram of a flow path structure 900A according to a first modification, and is a diagram for comparison with FIG. 7.

[0076] In the above-described embodiment, the gap adjusting member 98 is provided on the side of the flow path forming member 90, but it may be provided on the side of the case 2 as in the first modification example shown in FIG. 12. In this case, as shown in FIG. 12, the gap adjusting member 98 may be provided in a manner of facing only the convex portion 91 in the radial direction.

[0077] Even with such a first modification example, the same effects as those of the above-described embodiment are achieved. In addition, in a further modification example, the gap adjusting member 98 may be provided on the side of the case 2 as in the first modification example in addition to the side of the flow path forming member 90 as in the above-described embodiment.

[0078] FIG. 13 is an explanatory view of the flow path structure 900B according to the second modification example and is a view for comparison with FIG. 7.

[0079] In the above-described embodiment, the gap adjusting member 98 is provided on the side of the flow path forming member 90, but it may be provided on the side of the case 2 as in the second modification example shown in FIG. 13. In this case, as shown in FIG. 13, the gap adjusting member 98 may be provided in a manner of facing the entire flow path forming member 90 in the radial direction.

[0080] Even with such a second modification example, the same effects as those of the above-described embodiment are achieved. In addition, in a further modification example, the gap adjusting member 98 may be provided on the side of the case 2 as in the second modification example in addition to the side of the flow path forming member 90 as in the above-described embodiment.

[0081] As described above in detail for each embodiment, the present invention is not limited to a specific embodiment, and various modifications and changes are possible within the scope described in the claims. In addition, it is also possible to combine all or a plurality of the constituent elements of the above-described embodiments.

[0082] For example, in the above-described embodiment, the convex portion 91 is in the form of a convex strip or rib extending in the circumferential direction, but the extending direction is arbitrary. For example, instead of or in addition to the convex strip or rib extending in the circumferential direction, a convex strip or rib extending in the axial direction may be provided. In this case, the refrigerant flow path may be formed to flow in the circumferential direction while reciprocating the cooling water in the axial direction. Further, the convex portion 91 may be in the form of pin fins (for example, cylindrical columns).

[0083] Also, in the above-described embodiment, the convex portion 91 is formed on the side of the flow path forming member 90. Instead of or in addition to this, a similar convex portion may be formed on the case 2. In this case, the convex portion on the case 2 side may be formed in a manner radially opposed to the convex portion 91, or may be formed in a manner not radially opposed to the convex portion 91. In either case, by providing the gap adjusting member 98 in association with the convex portion 91 or the convex portion on the case 2 side, the same effect as in the above-described embodiment can be achieved.

Explanation of Reference Numerals

[0084] 100 ··· Vehicle drive device, 2 ··· Case (first flow path forming member), 1 ··· Rotating electric machine (drive source), 11 ··· Stator core, 90 ··· Flow path forming member (second flow path forming member), 91 ··· Convex portion (flow regulating portion), 98 ··· Gap adjusting member (third flow path forming member)

Claims

1. a first flow path forming member; a second flow path forming member facing the first flow path forming member and forming a flow path for refrigerant between the first flow path forming member and the second flow path forming member; a third flow path forming member having a higher coefficient of thermal expansion than the second flow path forming member, and the second flow path forming member has a flow regulating portion for regulating the flow of refrigerant in the flow path, the flow regulating portion protrudes toward the first flow path forming member and faces the first flow path forming member with a gap therebetween, and the third flow path forming member is provided on an end face of the flow regulating portion facing the first flow path forming member or on a surface of the first flow path forming member facing the flow regulating portion, a vehicle drive device.

2. further comprising a rotating electric machine that generates a driving force for driving a wheel, one of the first flow path forming member and the second flow path forming member is shrink-fitted to the radially outer side of the stator core of the rotating electric machine, and the other of the first flow path forming member and the second flow path forming member is disposed on the radially outer side of the one, the vehicle drive device according to claim 1.

3. the flow regulating portion is in the form of a rib or a protrusion extending in the axial direction, the circumferential direction, or a combination of these directions of the rotating electric machine, the vehicle drive device according to claim 1.

4. the cross-sectional area of the flow path is larger when the temperature of the refrigerant in the flow path is a first temperature than when the temperature of the refrigerant in the flow path is a second temperature higher than the first temperature, the vehicle drive device according to claim 1.

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