Motor unit

Abstract

A motor unit comprising a dynamo-electric machine, a motor case, an inverter, an inverter case, a plate-shaped motor bus bar connected to the dynamo-electric machine at one end, a plate-shaped inverter bus bar connected to the inverter at one end, and a terminal block to which the motor bus bar and inverter bus bar are fixed with a bolt and a nut, the motor case and inverter case being integrated into a single unit, wherein the nut is held on the terminal block so as to be movable in the axial direction of the bolt, and the bolt penetrates through a through-hole in each of the motor bus bar and the inverter bus bar and is fastened to the nut. The motor unit further comprises a cover member formed from an insulating member, the cover member being equipped with a lid that is fixed to the motor case and a protrusion that protrudes from the lid to the inside of the motor case and presses the contact area between the motor busbar and the inverter busbar directly or via the bolt to the terminal block.

Description

[Technical Field]

[0001] The present invention relates to a motor unit. [Background technology]

[0002] A known configuration is one in which a rotating electric machine that drives a vehicle is integrated with an inverter that controls the rotating electric machine by mounting the inverter on a motor case that houses the rotating electric machine. JP2012-170177A discloses a configuration in which a rotating electric machine and an inverter are integrated together, and bus bars extending from stator coil terminals of the rotating electric machine are connected to the inverter via a terminal block that is integrally formed with a fixing base that is arranged to cover an opening of the motor case. Summary of the Invention

[0003] However, there are dimensional tolerances among components such as the motor case, the mounting base, the terminal block, and the bus bar. If a gap occurs between the terminal block and the bus bar due to the tolerance, the bus bar must be deformed to fill the gap when fastening the bus bar to the terminal block. Fastening in this manner requires that part of the fastening axial force of the screw be used to deform the bus bar, which can result in an inability to obtain the desired fastening force and an increase in contact resistance at the fastening portion.

[0004] Therefore, an object of the present invention is to reduce the fastening axial force used to deform a bus bar when the bus bar is fastened to a terminal block with screws, thereby suppressing an increase in contact resistance.

[0005] According to one aspect of the present invention, there is provided a motor unit including a rotating electric machine, a motor case that houses the rotating electric machine, an inverter that controls power supplied to the rotating electric machine, an inverter case that houses the inverter, a plate-shaped motor bus bar having one end connected to the rotating electric machine, a plate-shaped inverter bus bar having one end connected to the inverter, and a terminal block to which the motor bus bar and the inverter bus bar are fixed with bolts and nuts, the motor case and the inverter case being integrated together. In this motor unit, the nuts are held on the terminal block so as to be movable in the axial direction of the bolts. The bolts pass through through holes provided in the motor bus bar and the inverter bus bar and are fastened to the nuts. The motor unit further includes a cover member made of an insulating material, the cover member having a lid portion that is fixed to the motor case, and a protrusion that protrudes from the lid portion toward the inside of the motor case and presses contact portions between the motor bus bar and the inverter bus bar against the terminal block directly or via a bolt. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a schematic diagram of a motor unit according to an embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view of the terminal block and its surroundings. [Figure 3] FIG. 3 is a diagram illustrating an example of a nut holding portion and a nut. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. [Figure 5] FIG. 5 is a cross-sectional view showing a general bus bar connection structure in a state before bolts are fastened. [Figure 6] FIG. 6 is a cross-sectional view showing a state of a typical bus bar connection structure after bolt fastening. [Figure 7] FIG. 7 is a cross-sectional view of the periphery of a terminal block of a motor unit according to a first modified example. [Figure 8] FIG. 8 is a diagram showing an example of a state after deformation of the cover member according to the first modified example. [Figure 9]FIG. 9 is a diagram showing another example of the state of the cover member according to the first modified example after deformation. [Figure 10] FIG. 10 is a cross-sectional view of the periphery of a terminal block of a motor unit according to a second modified example. DETAILED DESCRIPTION OF THE INVENTION

[0007] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0008] FIG. 1 is a schematic diagram of a motor unit 1 according to this embodiment.

[0009] The motor unit 1 shown in Fig. 1 is mounted on an electric vehicle. The electric vehicle referred to here includes so-called battery electric vehicles and hybrid electric vehicles.

[0010] The motor unit 1 includes a battery (not shown) as a power source, a rotating electric machine (hereinafter also referred to as an electric motor) 5 as a drive source for driving the wheels, and an inverter 4 electrically connected to the battery and the electric motor 5. The motor unit 1 drives the electric motor 5 using power discharged from the battery, and charges the battery using power generated by the electric motor 5.

[0011] The electric motor 5 is a three-phase AC motor consisting of a stator 5A, a rotor shaft 5B, and a rotor 5C, and equipped with a U-phase terminal, a V-phase terminal, and a W-phase terminal. It basically functions as a drive source and also functions as a generator during regeneration, such as when the vehicle is decelerating.

[0012] The inverter 4 is a power conversion device electrically connected to the battery and the electric motor 5. The inverter 4 basically converts DC power from the battery into AC power and supplies it to the electric motor 5, and during regeneration, converts AC power from the electric motor 5 into DC power and supplies it to the battery.

[0013] The electric motor 5 is housed in a motor case 2, and the inverter 4 is housed in an inverter case 3. The motor case 2 and the inverter case 3 are formed by casting, for example, an aluminum alloy. Although the motor case 2 and the inverter case 3 are integrally formed in FIG. 1, they may be manufactured separately and then integrated by connecting them with bolts or the like. Furthermore, although the inverter case 3 is formed above the motor case 2 in the vertical direction of the vehicle in FIG. 1, this is not limiting and the inverter case 3 may be formed, for example, at the rear side in the longitudinal direction of the vehicle.

[0014] The motor case 2 has a cylindrical space corresponding to the outer shape of the electric motor 5, and the electric motor 5 is fixed in this space.

[0015] The inverter case 3 has a box-shaped space that houses the semiconductor modules, capacitors, controller, etc. that constitute the inverter 4, as well as a cooler for cooling them. The top surface of the inverter case 3 is closed by a lid (not shown).

[0016] The electric motor 5 and inverter 4 accommodated as described above are electrically connected via the inverter bus bar 6 and the motor bus bar 8 (see FIG. 2). The specific configuration of the connection between the inverter bus bar 6 and the motor bus bar 8 will be described later.

[0017] The inverter bus bar 6 here is a general term for the U-phase inverter bus bar 6U, the V-phase inverter bus bar 6V, and the W-phase inverter bus bar 6W. Similarly, the motor bus bar 8 is a general term for the motor bus bars for the U-phase, V-phase, and W-phase. When it is not necessary to distinguish which phase they belong to, they will be referred to as the inverter bus bar 6 and the motor bus bar 8, respectively.

[0018] One end of the U-phase inverter bus bar 6U, the V-phase inverter bus bar 6V, and the W-phase inverter bus bar 6W is connected to the U-phase connection part 4U, the V-phase connection part 4V, and the W-phase connection part 4W of the inverter 4, respectively, and the other end is connected to the motor bus bar 8 at a terminal block 10 described later. A current sensor 7U for detecting the U-phase current is attached to the U-phase inverter bus bar 6U. Similarly, current sensors 7V and 7W are attached to the V-phase inverter bus bar 6V and the W-phase inverter bus bar 6W.

[0019] The motor unit 1 configured as described above is mounted on the frame of the vehicle via multiple mounts (not shown) so that the axial direction of the rotor shaft 5B (hereinafter simply referred to as the "axial direction") is perpendicular to the fore-and-aft direction of the vehicle. The motor unit 1 may be mounted in a motor room provided at the front of the vehicle, under the floor at the rear of the vehicle, or both at the front and rear of the vehicle.

[0020] Next, a specific structure of the connection between the inverter bus bar 6 and the motor bus bar 8 (hereinafter also referred to as the bus bar connection structure) will be described with reference to FIG.

[0021] 2 is a cross-sectional view of the motor unit 1 along a plane perpendicular to the vehicle longitudinal direction, around the terminal block 10. The connection portions between the inverter bus bars 6 and the motor bus bars 8 have the same structure for the U-phase, V-phase, and W-phase, and the W-phase will be described here.

[0022] The terminal block 10 is provided inside the motor case 2. The terminal block 10 also includes a nut holding portion 13 and a nut 12 housed in the nut holding portion 13. Here, the nut holding portion 13 and the nut 12 will be described with reference to FIGS. 3 and 4.

[0023] FIG. 3 is a view showing an example of the nut holding portion 13 and the nut 12 as viewed from the axial direction, and FIG. 4 is a cross-sectional view taken along line IV-IV in FIG.

[0024] The nut holding portion 13 has a hole 13B having a rectangular cross section. A rod-shaped support member 13A extending in the depth direction of the hole 13B is disposed on each side surface of the hole 13B.

[0025] Nut 12 has a rectangular cross section and is a so-called floating nut that is housed within hole 13B and is free to move in the depth direction, but is restricted from rotation about bolt hole 12A. Note that the shapes of hole 13B and nut 12 are not limited to those described above, and other shapes may be used as long as they function as a floating nut.

[0026] Returning to the explanation of Figure 2.

[0027] The motor bus bar 8W is formed from a flat plate-shaped member and includes an arm portion 8W-1 that extends in a direction parallel to the rotation axis from the coil end of the stator of the electric motor 5 as its base end, and a motor-side fastened portion 8W-2 that extends in a direction perpendicular to the rotation axis from the tip of the arm portion 8W-1. A through-hole 16 through which the bolt 11 passes is provided in the motor-side fastened portion 8W-2.

[0028] The inverter bus bar 6W is also formed of a flat plate-shaped member. The inverter bus bar 6W has an inverter-side fastened portion 6W-1 that intersects the boundary surface S between the motor case 2 and the inverter case 3 and extends from the inverter case 3 to the motor case 2. The inverter-side fastened portion 6W-1 is in an unmolded state (i.e., unmolded state), and has a through-hole 17 near its end on the motor case 2 side, through which the bolt 11 passes.

[0029] The motor-side fastened portion 8W-2 and the inverter-side fastened portion 6W-1 are in surface contact with each other, with at least a portion of their through holes overlapping, and are fastened together in this state by bolts 11 and nuts 12. The surface-contacting portions of the motor-side fastened portion 8W-2 and the inverter-side fastened portion 6W-1 are pressed against the terminal block 10 by a cover member 14, either directly or via a bolt 11. The cover member 14 is formed, for example, from an insulating resin material, and includes a lid portion 14-1 that closes the access hole in the motor case 2 and a protrusion 14-2 that protrudes from the lid portion 14-1 toward the inside of the motor case 2. The protrusion 14-2 presses the surface-contacting portions of the motor-side fastened portion 8W-2 and the inverter-side fastened portion 6W-1, either directly or via a bolt 11. A seal member 15 is provided on the portion of the motor case 2 where the cover member 14 is attached to ensure waterproofing.

[0030] Next, the effects of the busbar connection structure described above will be described with reference to Fig. 2, Fig. 5, and Fig. 6. Fig. 5 and Fig. 6 are cross-sectional views showing a general busbar connection structure different from that of this embodiment, with Fig. 5 showing the state before fastening with bolts 11 and Fig. 6 showing the state fastened with bolts 11. The busbar connection structure of Fig. 5 and Fig. 6 differs from the busbar connection structure of this embodiment shown in Fig. 2 in that nuts 22 of terminal block 20 are fixed and that cover member 14 is not provided.

[0031] The motor unit 1 is compact by integrating the motor case 2, which houses the electric motor 5, and the inverter case 3, which houses the inverter 4. However, this integrated configuration requires complex routing of the motor bus bar 8 and the inverter bus bar 6 to accommodate the layout of the electric motor 5 and the inverter 4, resulting in a long bus bar path. As a result, when vibrations are input while the vehicle is running, the amplitude of vibrations of the motor bus bar 8 and the inverter bus bar 6 increases, potentially placing unexpected loads on the motor bus bar 8 and the inverter bus bar 6. This problem can be solved by providing a terminal block 20 to fasten the motor bus bar 8 and the inverter bus bar 6 thereto, as the fastening points act as vibration nodes and suppress the vibration. However, due to dimensional tolerances of the bus bars 6, 8, the terminal block 20, and other components, axial gaps may occur between the inverter-side fastened portion 6W-1, the motor-side fastened portion 8W-2, and the nut 22 of the terminal block 20, as shown in FIG. 5 . When bolt 11 is tightened with this gap formed, as shown in Figure 6, both inverter-side fastened portion 6W-1 and motor-side fastened portion 8W-2 deform toward terminal block 20, and their connection portions are fixed in this deformed state until they come into contact with nut 22 fixed to terminal block 20. In this fixed state, elastic forces are generated as the inverter-side fastened portion 6W-1 and motor-side fastened portion 8W-2 deform, and these elastic forces act in a direction that moves the connection portions away from nut 22. As a result, part of the fastening axial force of bolt 11 and nut 22 is consumed to offset the elastic forces, and there is a risk that insufficient fastening axial force will increase the contact resistance between inverter-side fastened portion 6W-1 and motor-side fastened portion 8W-2.

[0032] In contrast, in the busbar connection structure of this embodiment, nut 12 is a floating nut, so when bolt 11 is tightened with the above-mentioned axial gap remaining, the inverter-side fastened portion 6W-1 and the motor-side fastened portion 8W-2 are deformed toward each other. Therefore, the elastic force generated when fastened by bolt 11 and nut 12 is smaller than that in the state shown in FIG. 6. Furthermore, in the busbar connection structure of this embodiment, cover member 14 presses inverter-side fastened portion 6W-1 and motor-side fastened portion 8W-2 against terminal block 10. This allows the connection between inverter-side fastened portion 6W-1 and motor-side fastened portion 8W-2 to function as a vibration node, thereby suppressing vibration and preventing an increase in contact resistance at the connection.

[0033] Furthermore, the inverter bus bar 6 of this embodiment has an inverter-side fastened portion 6W-1 extending from the inverter case 3 to the motor case 2 and is unmolded, making it less rigid and more susceptible to deformation than a bus bar with a short length or molded length. The motor bus bar 8 of this embodiment also has an arm portion 8W-1 extending in the axial direction and a motor-side fastened portion 8W-2 extending from the end of the arm portion 8W-1 in a direction perpendicular to the axial direction, making it more susceptible to deformation due to axial force. This facilitates fastening with the bolt 11. Furthermore, the cover member 14 is made of an insulating resin material, so there is no electrical short circuit even if it comes into contact with the bolt 11, the motor bus bar 8, or the inverter bus bar 6.

[0034] As described above, this embodiment provides a motor unit 1 including an electric motor 5 (rotating electric machine), a motor case 2 that houses the electric motor 5, an inverter 4 that controls the power supplied to the electric motor 5, an inverter case 3 that houses the inverter 4, a plate-shaped motor bus bar 8 having one end connected to the electric motor 5, a plate-shaped inverter bus bar 6 having one end connected to the inverter 4, and a terminal block 10 to which the motor bus bar 8 and the inverter bus bar 6 are fixed with bolts 11 and nuts 12, and in which the motor case 2 and the inverter case 3 are integrated. In this motor unit 1, the nuts 12 are held by the terminal block 10 so as to be movable in the axial direction of the bolts 11, and the bolts 11 are fastened to the nuts 12 by passing through through holes provided in the motor bus bar 8 and the inverter bus bar 6, respectively. The motor case 2 further includes a cover member 14 made of an insulating material, which includes a lid portion 14-1 fixed to the motor case 2 and a protrusion 14-2 protruding from the lid portion 14-1 toward the inside of the motor case 2 and pressing the contact portion between the motor bus bar 8 and the inverter bus bar 6 against the terminal block 10 directly or via a bolt 11. This reduces the axial fastening force used to deform the motor bus bar 8 and the inverter bus bar 6, thereby suppressing an increase in contact resistance, even when bolt fastening is performed with variations in the dimensions of each component, such as the motor bus bar 8 and the inverter bus bar 6, within their tolerance ranges. Furthermore, by pressing the connection portion between the motor bus bar 8 and the inverter bus bar 6 against the terminal block 10 with the cover member 14, the connection portion becomes a vibration node, thereby suppressing vibration of the motor bus bar 8 and the inverter bus bar 6. Furthermore, because the cover member 14 is made of an insulating material, no electrical short circuit occurs.

[0035] In this embodiment, the inverter bus bar 6 crosses the boundary surface S between the motor case 2 and the inverter case 3, extends from the inverter case 3 to the motor case 2, and includes an unmolded inverter-side fastened portion 6W-1. The motor bus bar 8 includes an arm portion 8W-1 extending from the coil end of the stator 5A of the electric motor 5 as a base end in a direction parallel to the rotational axis of the electric motor 5, and a motor-side fastened portion 8W-2 extending from the tip of the arm portion 8W-1 in a direction perpendicular to the rotational axis of the electric motor 5. The inverter-side fastened portion 6W-1 and the motor-side fastened portion 8W-2 are provided with through holes 16 and 17, respectively. Fastening the inverter bus bar 6 and the motor bus bar 8 together during the assembly process of the motor unit 1 is generally difficult due to misalignment caused by dimensional variations between the components. Forcibly fastening them with bolts and nuts when the misalignment exists can cause stress to the components or result in insufficient fastening axial force. However, the inverter bus bar 6 and motor bus bar 8 of the motor unit 1 according to this embodiment both have extended portions, and the inverter bus bar 6 is not molded, so its rigidity is reduced. Therefore, even if the components are fastened together with misalignment, stress on each component can be reduced and the fastening axial force can be ensured.

[0036] Next, modifications of this embodiment will be described with reference to Figures 7 to 10. Note that the modifications described below fall within the scope of the present invention, just like the above-described embodiment.

[0037] [First Modification] Fig. 7 is a cross-sectional view showing a bus bar connection structure according to a first modified example. The difference from Fig. 2 is the shape of the cover member 14. The following description will focus on this difference.

[0038] The motor unit 1 according to this modification is arranged in a motor room provided at the front of the vehicle, in an area sandwiched between a pair of side members, with the axial direction perpendicular to the longitudinal direction of the vehicle.

[0039] The cover member 14 according to this modification includes a lid portion 14-1 that closes an access hole provided on a side surface of the motor case 2 in the vehicle width direction, and a protrusion portion 14-2 that protrudes from the lid portion 14-1 toward the inside of the motor case 2. The protrusion portion 14-2 presses the portions of the motor-side fastened portion 8W-2 and the inverter-side fastened portion 6W-1 that are in surface contact, either directly or via a bolt 11. The protrusion portion 14-2 also includes a low-strength portion 14-3 that is weaker than the other portions of the protrusion portion 14-2.

[0040] The low-strength portion 14-3 has at least the strength to withstand deformation due to axial stress generated when the cover portion 14-1 is fixed to the work hole and the protrusion 14-2 is in surface contact with the motor-side fastened portion 8W-2 and the inverter-side fastened portion 6W-1, or when the protrusion 14-2 is in surface contact with the bolt 11. The strength of the low-strength portion 14-3 is set to a magnitude that will cause deformation when a predetermined axial force is applied in the above-mentioned state. Note that "deformation" here also includes fracture. The magnitude of the predetermined force is not particularly limited, but for example, if the cover member 14 does not have the low-strength portion 14-3, the protrusion 14-2 will press against the cover member 14, causing deformation of the inverter bus bar 6, motor bus bar 8, terminal block 10, etc.

[0041] If the vehicle collides head-on with another vehicle or an obstacle, the side members may be deformed by the input from the front of the vehicle and may interfere with the side surfaces in the vehicle width direction of the motor unit 1. In this case, if the side members press against the cover member 14, the motor bus bar 8 or the inverter bus bar 6 may be pressed through the cover member 14 and break, causing a short circuit with the motor case 2 or the inverter case 3. However, if low-strength portion 14-3 is provided in the protruding portion 14-2, the input to the motor bus bar 8, the inverter bus bar 6, etc. is alleviated by the deformation of the low-strength portion 14-3, thereby preventing the above-mentioned short circuit.

[0042] The shape of the low strength portion 14-3 is not particularly limited, but it is more preferable that the shape be such that it can disperse the axial input in the vertical direction of the vehicle body by deformation.

[0043] 8 and 9 show examples of shapes capable of dispersing axial force in the vertical direction of the vehicle body. The low-strength portion 14-3 in FIG. 8 is bent convexly upward in the vertical direction of the vehicle body relative to the axial direction. With this shape, when pressed against a side member or the like, the bent portion deforms to form a more acute angle, allowing the axial force to be dispersed upward in the vertical direction of the vehicle body. Also, the low-strength portion 14-3 in FIG. 9 is linear and inclined in the vertical direction of the vehicle body relative to the axial direction. Because the positions of both ends of the low-strength portion 14-3 in the vertical direction of the vehicle body are offset, a moment is generated in the low-strength portion 14-3 when an axial force is applied. In the case of the shape shown in FIG. 9, a moment is generated that rotates the low-strength portion 14-3 clockwise in FIG. 9. That is, with the shape shown in FIG. 9, when the cover portion 14-1 is pressed against a side member or the like, the low-strength portion 14-3 deforms in response to the moment, allowing the axial force to be dispersed downward in the vertical direction of the vehicle body.

[0044] As described above, in this modified example, the vehicle has a pair of side members at the front of the vehicle body that are spaced apart in the vehicle width direction and extend in the front-to-rear direction of the vehicle body, the motor case 2 is located in an area sandwiched between the pair of side members, the cover portion 14-1 is fixed to the side surface of the motor case 2 in the vehicle width direction, and the protruding portion 14-2 has a low-strength portion 14-3 that is weaker than other portions of the protruding portion 14-2. As a result, even if the side members are deformed by a collision load and interfere with the motor unit 1, the deformation of the low-strength portion 14-3 can reduce the load applied from the side members to the inverter bus bar 6 and the motor bus bar 8.

[0045] [Second Modification] Fig. 10 is a cross-sectional view showing a bus bar connection structure according to a second modified example. The difference from Fig. 2 is the structure of the cover member 14. The cover member 14 of this modified example includes a heat transfer material 23 formed of a material with a higher thermal conductivity than the material forming the cover member 14, between the end of the protrusion 14-2 on the lid portion 14-1 side and the end of the protrusion 14-2 on the terminal block 10 side. The heat transfer material 23 is formed, for example, of a sheet-like material and attached to the outer surface of the protrusion 14-2. Alternatively, the protrusion 14-2 may be hollow and the heat transfer material 23 may be attached to the inner surface thereof.

[0046] By providing the heat transfer material 23 on the protrusion 14-2 as described above, heat from the fastening portion between the inverter bus bar 6 and the motor bus bar 8 is easily transferred to the lid portion 14-1.

[0047] The motor case 2 is generally cooled by a refrigerant such as cooling water or oil to cool the coil of the electric motor 5. For this reason, heat from the lid portion 14-1 fixed to the motor case 2 easily flows to the motor case 2. In other words, by providing the heat transfer material 23 as described above, heat from the fastening portion between the inverter bus bar 6 and the motor bus bar 8 can easily be released to the motor case 2.

[0048] As described above, in this modification, the cover member 14 is provided with the heat transfer material 23, which has a higher thermal conductivity than the material forming the cover member 14, between the end of the protrusion 14-2 on the lid portion 14-1 side and the end of the protrusion 14-2 on the terminal block 10 side. This makes it easier for heat to escape from the fastening portion between the inverter bus bar 6 and the motor bus bar 8 to the motor case 2.

[0049] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments.

Claims

1. A rotating electric machine, a motor case that houses the rotating electric machine; an inverter that controls power supplied to the rotating electric machine; an inverter case that houses the inverter; a plate-shaped motor bus bar having one end connected to the rotating electric machine; A plate-shaped inverter bus bar with one end connected to the inverter a terminal block to which the motor bus bar and the inverter bus bar are fixed by bolts and nuts; Equipped with In the motor unit in which the motor case and the inverter case are integrated, the nut is held by the terminal block so as to be movable in the axial direction of the bolt, the bolts pass through through holes provided in the motor bus bars and the inverter bus bars, respectively, and are fastened to the nuts; The motor unit further includes a cover member formed of an insulating material, the cover member having a lid portion fixed to the motor case and a protrusion portion protruding from the lid portion toward the inside of the motor case and pressing the bolt, thereby pressing the contact portion between the motor bus bar and the inverter bus bar against the terminal block.

2. 2. The motor unit according to claim 1, which is mounted on a vehicle, The vehicle has a pair of side members at the front of the vehicle body, spaced apart in the vehicle width direction and extending in the vehicle front-rear direction, the motor case is disposed in a region sandwiched between the pair of side members, the cover portion is fixed to a side surface of the motor case in a vehicle width direction, The protrusion has a low-strength portion having a strength lower than that of other portions of the protrusion. Motor unit.

3. 3. The motor unit according to claim 2, A motor unit in which the low-strength portion is bent convexly upward in the vertical direction of the vehicle body relative to the axial direction of the rotor of the rotating electric machine, or is linear and inclined in the vertical direction of the vehicle body relative to the axial direction of the rotor of the rotating electric machine.

4. The motor unit according to any one of claims 1 to 3, A motor unit in which the cover member is provided with a heat transfer material having a higher thermal conductivity than the material forming the cover member between the end of the protrusion on the lid portion side and the end of the protrusion on the terminal block side.

5. 2. The motor unit according to claim 1, the inverter bus bar extends from the inverter case to the motor case, crossing a boundary surface between the motor case and the inverter case, and includes an inverter-side fastened portion in an unmolded state; the motor bus bar includes an arm portion extending from a coil end of a stator of the rotary electric machine as a base end along a direction parallel to a rotation axis of the rotary electric machine, and a motor-side fastened portion extending from a tip end of the arm portion along a direction perpendicular to the rotation axis, The motor unit has the through hole provided in each of the inverter side fastened portion and the motor side fastened portion.

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