Electric drive system for vehicles

Abstract

To realize an electric drive system for vehicles that makes it easier to improve sound insulation performance. [Solution] The electric drive unit 100 for a vehicle includes a rotating electric machine 11, an output member 12 that is driven and connected to the wheels WH of the vehicle V, a power transmission mechanism 13 that transmits driving force between the rotating electric machine 11 and the output member 12, a case 14 that houses the rotating electric machine 11 and the power transmission mechanism 13, a mounting mechanism 21 for attaching the case 14 to the vehicle V, and a sound insulation cover 25. The mounting mechanism 21 includes a main body 2S supported by the vehicle V, and a vibration reducing member 245 that is arranged at the mounting portion 24 between the main body 2S and the case 14 to reduce vibrations transmitted through the mounting portion 24. The sound insulation cover 25 is supported by the main body 2S and is arranged to cover the case 14 without contacting the case 14.

Description

Technical Field

[0001] The present invention relates to an electric drive device for a vehicle that is attached to a vehicle.

Background Art

[0002] An electric drive device for a vehicle, which is a driving force source for wheels in a vehicle, may cause vibrations during driving to be a source of noise (noise source) for the surroundings. And a technique for soundproofing the sound generated from the noise source existing in the vehicle is disclosed in, for example, Patent Document 1. Hereinafter, in the description of this background art, the reference signs and names in Patent Document 1 are cited in parentheses.

[0003] Patent Document 1 discloses a soundproof cover (soundproof cover 1) that soundproofs the sound generated from a noise source (intake manifold 2). The soundproof cover (soundproof cover 1) disclosed in Patent Document 1 soundproofs the sound generated from the noise source (intake manifold 2) by covering the noise source (intake manifold 2). This soundproof cover (soundproof cover 1) fully exhibits its soundproofing performance by being directly fixed to the noise source (intake manifold 2) in a state where the entire surface (seal layer 12) thereof abuts against the noise source (intake manifold 2) without a gap.

[0004] Here, in an electric drive device for a vehicle, noise is likely to occur in a rotating electric machine or a power transmission mechanism. This noise propagates from the case that houses the rotating electric machine or the power transmission mechanism to its surroundings. Therefore, it can be expected that by covering the case with the soundproof cover (soundproof cover 1) disclosed in Patent Document 1, the sound propagating from the case to its surroundings can be soundproofed.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

[0006] However, because the surface of the case of an electric drive unit for a vehicle has a complex and uneven shape, it is difficult to ensure that the entire surface of the sound insulation cover (soundproof cover 1) is in contact with the case surface without any gaps. In addition, a joint is required between the case and the sound insulation cover (soundproof cover 1), and vibrations can be transmitted to the sound insulation cover (soundproof cover 1) through this joint, potentially generating noise from the sound insulation cover (soundproof cover 1) itself. For these reasons, there were limitations to improving the sound insulation performance of the electric drive unit for a vehicle with a sound insulation cover (soundproof cover 1) as disclosed in Patent Document 1.

[0007] Therefore, there is a need for electric drive systems for vehicles that can easily improve sound insulation performance. [Means for solving the problem]

[0008] The electric drive system for vehicles relating to this disclosure comprises a rotating electric machine and, An output member that is driven and connected to the vehicle's wheels, A power transmission mechanism that transmits driving force between the rotating electric machine and the output member, A case housing the aforementioned rotating electric machine and the aforementioned power transmission mechanism, A mounting mechanism for attaching the case to the vehicle, Soundproof cover and, An electric drive system for a vehicle, comprising: The mounting mechanism comprises a main body supported by the vehicle, and a vibration reducing member disposed at the mounting portion between the main body and the case to reduce vibrations transmitted through the mounting portion. The sound-insulating cover is supported by the main body and is positioned to cover the case without contacting it.

[0009] With this configuration, the sound insulation cover covers the case without contacting it, and vibration-reducing members are placed at the mounting point between the main body of the mounting mechanism and the case, thus reducing vibrations transmitted to the sound insulation cover from the rotating electric machine and power transmission mechanism. Therefore, it is possible to cover the case with the sound insulation cover and enhance the sound insulation performance of the sound insulation cover, while avoiding the sound insulation cover itself becoming a noise source due to vibration. In addition, since it is possible to reduce the need to give the sound insulation cover functions other than sound insulation, such as vibration reduction, it is easier to increase the design flexibility of the sound insulation cover, and consequently, it is easier to improve the sound insulation performance of electric drive systems for vehicles. [Brief explanation of the drawing]

[0010] [Figure 1] Skeleton diagram of an electric drive system for a vehicle according to an embodiment. [Figure 2] Exploded perspective view of the vehicle electric drive system according to the embodiment. [Figure 3] Perspective view of the vehicle electric drive system according to the embodiment. [Figure 4] Enlarged view of one of the pair of main body members shown in Figure 2. [Figure 5] Enlarged view of the other of the pair of main body members shown in Figure 2. [Figure 6] Exploded perspective view showing an example of an electric drive system for a vehicle according to another embodiment. [Modes for carrying out the invention]

[0011] An electric vehicle drive system 100 according to an embodiment will be described with reference to Figures 1 to 5. As shown in Figure 1, the electric vehicle drive system 100 is mounted on a vehicle V that operates by converting electricity into driving force. Examples of such a vehicle V include hybrid vehicles and electric vehicles.

[0012] The electric drive system 100 for a vehicle includes a drive unit 1 that generates driving force and a coupling structure 2 that connects the drive unit 1 to the vehicle V.

[0013] [Drive system] As shown in FIG. 1, the drive device 1 includes a rotary electric machine 11, an output member 12 that outputs the driving force of the rotary electric machine 11, a power transmission mechanism 13 that transmits the driving force between the rotary electric machine 11 and the output member 12, and a case 14. The case 14 houses the rotary electric machine 11 and the power transmission mechanism 13.

[0014] The rotary electric machine 11 at least has a function as a motor (electric motor) that generates power upon receiving power supply. Further, the rotary electric machine 11 may also have a function as a generator (electric generator) that generates power upon receiving power supply. The rotary electric machine 11 is electrically connected to a power storage device (not shown) such as a battery or a capacitor. Then, the rotary electric machine 11 generates a driving force by power running with the power stored in the power storage device.

[0015] In the present embodiment, the rotary electric machine 11 includes a stator 111 and a rotor 112. In the example shown in FIG. 1, an inner rotor type rotary electric machine 11 is shown. In the rotary electric machine 11 illustrated in FIG. 1, the rotor 112 is accommodated in a cylindrical stator 111 extending in the axial direction. In addition, the rotary electric machine 11 illustrated in FIG. 1 is of a rotating field type. Therefore, permanent magnets or electromagnets are provided on the rotor 112, and coils are provided on the stator 111.

[0016] The rotor 112 is rotationally connected to the power transmission mechanism 13 so as to rotate relative to the stator 111 and apply a rotational force to the power transmission mechanism 13. Here, in the present application, "rotationally connected" refers to a state in which two rotating elements are connected so as to be able to transmit a driving force, 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 two 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 engaging devices that selectively transmit rotation and driving force, for example, friction engaging devices, meshing type engaging devices, etc.

[0017] In this embodiment, the rotor 112 is rotatably supported by the case 14, and the stator 111 is fixed to the case 14. The rotor 112 illustrated in FIG. 1 includes a rotor core 113 and a rotor shaft 114 connected to rotate integrally with the rotor core 113. The rotor core 113 rotates around a rotation axis that overlaps the axis of the stator 111. The rotor shaft 114 is attached to the rotor core 113 and is rotatably supported by the case 14 via a bearing (not shown). The power transmission mechanism 13 is drivingly connected to the rotor shaft 114, and a rotational force is mutually transmitted between the power transmission mechanism 13 and the rotor shaft 114.

[0018] Further, in this embodiment, the stator 111 and the rotor 112 have a function of generating a rotational force transmitted to the power transmission mechanism 13 and a function of generating electric power by the rotational force transmitted from the power transmission mechanism 13. Specifically, the rotor core 113 constituting the rotor 112 rotates by exciting the coil of the stator 111. When the rotor core 113 rotates, a rotational force is transmitted to the power transmission mechanism 13 via the rotor shaft 114. On the other hand, the rotor core 113 may also be transmitted a rotational force from the power transmission mechanism 13 via the rotor shaft 114. Thereby, the rotor core 113 rotates and electric power is generated in the stator 111.

[0019] Since the rotor 112 rotates relative to the stator 111 in the rotating electrical machine 11, for example, as the rotor 112 rotates, components such as bearings for supporting the rotor 112 by the case 14 slide with the rotor 112. Also, vibration and noise may be generated from the rotating electrical machine 11 due to magnetostriction or the like. Therefore, the rotating electrical machine 11 may be a sound source that causes problems for passengers riding in the passenger compartment of the vehicle V.

[0020] The output member 12 is driven and connected to the wheels WH of the vehicle V. The wheels WH of the vehicle V are driven and connected to the rotating electric machine 11 via the output member 12 and the power transmission mechanism 13. Therefore, the wheels WH rotate as the rotating electric machine 11 generates rotational force. On the other hand, in this embodiment, the rotational force of the wheels WH is transmitted to the rotating electric machine 11 via the output member 12, causing the rotating electric machine 11 to generate electricity. For example, when the brakes are applied to a moving vehicle V, the braking force is transmitted to the rotating electric machine 11 as rotational force.

[0021] Hereafter, for the sake of explanation, the rotation axis of either the rotating electric machine 11 or the output member 12 will be referred to as the reference axis RX, and the direction along the reference axis RX will be referred to as the axial direction L. In this embodiment, the reference axis RX is the rotation axis of the output member 12. The rotation axis of the output member 12 illustrated in Figure 1 is coaxial with the rotation axis of the rotating electric machine 11. The direction perpendicular to the reference axis RX will be referred to as the radial direction R. The side of radial direction R closer to the reference axis RX will be referred to as the radially inner R1, and the side of radial direction R further from the reference axis RX will be referred to as the radially outer R2. The direction that circles around the reference axis RX will be referred to as the circumferential direction. Furthermore, in this application, the positional relationship between the two members may be described using the term "overlap" along with terms meaning direction. In this application, with respect to the arrangement of the two members, "overlapping in a specific viewing direction" means that when a virtual line parallel to the line of sight is moved in each direction perpendicular to that virtual line, there exists a region in which the virtual line intersects both members.

[0022] As described above, the power transmission mechanism 13 drives and connects the wheels WH of the vehicle V to the output member 12. The power transmission mechanism 13 includes, for example, a drive shaft, gears, and engaging elements such as a clutch and brake. In this embodiment, the power transmission mechanism 13 includes a reduction mechanism 131 that drives and connects to the rotor shaft 114 of the rotor 112 of the rotating electric machine 11, and a differential gear mechanism 132. The reduction mechanism 131 includes, for example, a planetary gear mechanism or a counter gear mechanism. The output member 12 is the part that drives and connects to the drive shaft WX connected to the wheel WH. For example, the output member 12 may be the part of the differential gear mechanism 132 that connects to the drive shaft WX. The power transmission mechanism 13 generates noise due to the rotation of its components and the sliding of its components against each other. Therefore, similar to the rotating electric machine 11, the noise generated by the power transmission mechanism 13 may be a problem for occupants in the passenger compartment of the vehicle V.

[0023] Case 14 comprises a wall surrounding a housing space S that houses the rotating electric machine 11 and the power transmission mechanism 13. The wall includes a peripheral wall portion 141, a side wall portion 142, and a cover portion 143. The peripheral wall portion 141 is the portion that surrounds the housing space S from the radially outer R2. The side wall portion 142 is the portion that covers the housing space S from one side in the axial direction L. The side wall portion 142 illustrated in Figure 1 is positioned to the left of the peripheral wall portion 141 in the plane of the paper and extends radially inward R1 from one end of the peripheral wall portion 141 in the axial direction L. The side wall portion 142 has a first opening 14A at a position that overlaps with the rotation axis of the output member 12 in the axial direction L. The output member 12 or a member that is driven and connected to the output member 12 is arranged to pass through the first opening 14A. The cover portion 143, like the side wall portion 142, is the portion that covers the housing space S from the axial direction L. The cover portion 143 covers the housing space S from the side opposite to the side where the side wall portion 142 is located in the axial direction L. The cover portion 143 illustrated in Figure 1 is located to the right of the circumferential wall portion 141 in the plane of the paper, and extends radially inward R1 from the end of the circumferential wall portion 141 opposite to the side where the side wall portion 142 is located. The cover portion 143 is detachable from the circumferential wall portion 141 and is fixed to the circumferential wall portion 141 with fastening components such as bolts, although details are not shown. The cover portion 143 illustrated in Figure 1, like the side wall portion 142, is also provided with a second opening 14B at a position that overlaps with the rotation axis of the output member 12 in the axial direction L. The output member 12 or a part of a member that is driven and connected to the output member 12 is also located in the second opening 14B, similar to the first opening 14A.

[0024] Sound and vibration generated by sound sources such as the rotating electric machine 11 and the power transmission mechanism 13 are transmitted to the case 14 and then propagate to various parts of the vehicle V. In addition, vibrations and sound transmitted to the case 14 may cause the case 14 itself to vibrate, making the case 14 a sound source. For this reason, it is preferable that the coupling structure 2 for connecting the drive unit 1, including the case 14, to the vehicle V is provided with vibration-reducing members and sound-insulating materials to block the propagation of sound. In particular, since the sound generated from the drive unit 1 can be a problem for occupants in the passenger compartment, it is preferable that a sound-insulating material be provided between the drive unit 1 and the passenger compartment.

[0025] [Connection structure] As shown in Figures 1 to 3, the connecting structure 2 includes a mounting mechanism 21 for attaching the case 14 to the vehicle V, and a sound insulation cover 25. The sound insulation cover 25 is positioned to cover the outer surface of the case 14.

[0026] The mounting mechanism 21 comprises a main body 2S supported by the vehicle V, and a vibration-reducing member 245 positioned at a mounting portion 24 between the main body 2S and the case 14 to reduce vibrations transmitted through the mounting portion 24. The main body 2S is connected to an appropriate part of the structure constituting the vehicle V by a mounting portion 23. As will be described later, in this embodiment, the mounting mechanism 21 comprises a pair of main body members 22 as the main body 2S. The mounting portion 24 is the part that forms the transmission path (hereinafter referred to as the load transmission path) for the load due to the weight of the drive unit 1 including the case 14 and the load due to vibrations of the drive unit 1. The vibration-reducing member 245 forms the part in the load transmission path that connects the case 14 and the main body 2S. The vibration-reducing member 245 insulates the case 14 and the main body 2S so that vibrations are not directly transmitted from the case 14 to the main body 2S. The vibration-reducing member 245 is made of a material with a lower modulus of elasticity than the main body 2S. In this embodiment, the main body 2S is made of iron, aluminum, or other metal, and the vibration reduction member 245 is made of vibration-damping rubber.

[0027] In this configuration, vibrations from the drive unit 1 are reduced by the vibration-reducing member 245 and transmitted to the main body 2S. Therefore, vibrations transmitted from the main body 2S through the mount 23 to the passenger compartment, as well as the noise generated by these vibrations, are reduced. This makes it less likely for noises of a level that would be problematic for occupants to reach the passenger compartment, improving passenger comfort. Furthermore, various characteristics of the electric vehicle drive unit 100, such as torque responsiveness, are affected by the rigidity of the mount mechanism 21. With this configuration, the rigidity of the mount mechanism 21 can be adjusted during the development stage of the vehicle V by changing the vibration-reducing member 245 with different moduli, thus allowing the various characteristics of the electric vehicle drive unit 100 to be adjusted on the vehicle electric vehicle drive unit 100 side. Therefore, compared to a configuration where the rigidity of the mount mechanism 21 can only be adjusted using parts on the vehicle V side, the overall development cost of the vehicle V can be reduced.

[0028] The sound insulation cover 25, although not shown in detail, comprises at least a laminated structure of a sound insulation layer and a sound absorption layer. The sound insulation layer obstructs the propagation of sound. For this reason, the sound insulation layer is made of a material with a lower modulus of elasticity than the material that makes up the case 14. For example, if the case 14 is made of aluminum, iron, or other metal, the sound insulation layer is made of resin. The sound absorption layer absorbs sound. For this reason, the sound absorption layer is made of foamed rubber, foamed urethane, polyethylene foam, or other foams. The sound insulation cover 25 can effectively block sound emitted from a sound source by positioning the sound absorption layer closer to the sound source relative to the sound insulation layer. In this embodiment, since the rotating electric machine 11 and the power transmission mechanism 13, which are sound sources, are located radially inward R1 relative to the case 14, the sound absorption layer is positioned radially inward R1 relative to the sound insulation layer.

[0029] The sound insulation cover 25 is supported by the main body 2S and is positioned to cover the case 14 without contacting the case 14. In detail, the sound insulation cover 25 covers at least a portion of the outer surface of the case 14. In the example shown in Figures 1 to 3, the sound insulation cover 25 covers the peripheral wall portion 141 of the case 14 with a gap in the radially outward direction R2. In detail, the sound insulation cover 25 covers the entire circumference of the peripheral wall portion 141 of the case 14. The sound insulation cover 25 does not cover the side wall portion 142 of the case 14 or the cover portion 143 of the case 14 from the axial direction L. The sound insulation cover 25 is fixed to the main body 2S.

[0030] The sound-insulating cover 25 covers at least a portion of the outer surface of the case 14 in the circumferential and axial directions L. In this embodiment, the sound-insulating cover 25 is supported by the main body 2S so as to cover the entire outer surface of the case 14 facing radially outward R2. The sound-insulating cover 25 illustrated in Figure 1 covers the entire circumferential area of ​​the case 14 in an axial view L, encompassing the circumferential wall portion 141, the side wall portion 142, and the cover portion 143. With this configuration, sound propagating radially outward R2 can be blocked over the entire circumferential area relative to the case 14.

[0031] The details of the structure of the mounting mechanism 21 and the sound insulation cover 25 are described below.

[0032] The mounting mechanism 21 comprises a pair of main body members 22 arranged opposite each other with the case 14 in between, as the main body portion 2S. The main body members 22 face each other with the case 14 in between from at least one of the axial direction L or radially outward direction R2. The main body members 22 are supported by the vehicle V by a mounting member 231 included in the mounting portion 23. The sound insulation cover 25 is arranged to connect the pair of main body members 22. In this embodiment, the sound insulation cover 25 is arranged continuously over the entire area in the opposing direction. Here, the opposing direction is the direction in which the pair of main body members 22 face each other.

[0033] In this embodiment, the pair of main body members 22 are arranged to sandwich the case 14 from both sides in the axial direction L. A mounting member 231 is attached to each of the pair of main body members 22 illustrated in Figures 1 to 3. An upper mount 232 is attached to the upper part of each of the pair of main body members 22 to support the weight of the drive unit 1 from above. The upper mount 232 is attached to the structure on the vehicle V side, and the structure on the vehicle V side holds the drive unit 1. A torque mount 233 is attached to the lower part of one of the pair of main body members 22 to receive the rotational force generated by the drive unit 1. The torque mount 233 is also attached to the structure on the vehicle V side, and the structure receives the reaction force of the rotational force generated by the drive unit 1.

[0034] In this embodiment, as shown in Figures 4 and 5, the main body member 22 is provided with an outer arrangement portion 221 located radially outward R2 from the outer edge of the case 14, on at least a portion of the outer edge of the pair of main body members 22 in an axial view along the axial direction L. In this embodiment, the outer arrangement portion 221 is provided around the entire circumference of the main body member 22. As described above, the sound insulation cover 25 is shaped to cover the entire circumference of the case 14. With this configuration, the sound insulation cover 25, which is shaped to cover the entire circumference of the case 14, can be fixed to the outer arrangement portion 221 provided around the entire circumference of the main body member 22, making it easy to stably fix the sound insulation cover 25 to the main body member 22. In addition, because the outer arrangement portion 221 is provided around the entire circumference of the main body member 22, when the sound insulation cover 25 is configured to cover the entire circumference, the sound insulation cover 25 can be shaped to extend linearly from one main body member 22 to the other main body member 22. In other words, the shape of the sound insulation cover 25 can be easily simplified.

[0035] The outer mounting portion 221 and the sound insulation cover 25 are fixed in a state where their relative positions are fixed. For this purpose, a fixing portion 222 is provided on at least one of the outer mounting portion 221 and the sound insulation cover 25. In this embodiment, the outer mounting portion 221 and the sound insulation cover 25 are fixed by fastening components (not shown). Therefore, the fixing portion 222 includes fastening components such as bolts and fastening portions provided on both the outer mounting portion 221 and the sound insulation cover 25. In detail, the fastening portion provided on the outer mounting portion 221 is a through hole that penetrates the outer mounting portion 221 in the axial direction L, and the fastening portion provided on the sound insulation cover 25 is a fastening hole that extends along the axial direction L.

[0036] Preferably, the fixing portion 222 is provided at a position different from the circumferential position where the mounting member 231 is attached to the main body member 22. In this embodiment, the mounting member 231 is provided on the upper and lower parts of one of the pair of main body members 22. The fixing portion 222 is provided at a position other than the upper and lower parts of the main body member 22 in an axial view L. With this configuration, the mounting position of the mounting member 231 and the position of the fixing portion 222 can be spaced apart, making it easier to attach the mounting member 231 to the main body member 22. Furthermore, if the fixing portion 222 has a hole-like shape, the mounting member 231 can be attached to a relatively rigid position on the main body member 22, so that the drive unit 1 can be stably mounted to the vehicle V.

[0037] In this embodiment, as shown in Figures 1 to 3, the sound insulation cover 25 is arranged to connect the outer arrangement portions 221 of each of the pair of main body members 22 in the axial direction L. More specifically, the sound insulation cover 25 is arranged over the entire area in the opposing direction where the pair of main body members 22 face each other, and over at least a portion of the circumferential direction. Preferably, the sound insulation cover 25 is arranged to be continuous over the entire area in the opposing direction and continuous over the entire circumference in the circumferential direction. With this configuration, since the sound insulation cover 25 covers the entire circumference of the case 14, it is easy to insulate sound that propagates around the drive device 1. In the example shown in Figures 2 and 3, the sound insulation cover 25 is arranged continuously over the entire area in the axial direction L in the space between the pair of main body members 22. The sound insulation cover 25 may also have a cover penetration portion (not shown) that penetrates in the radial direction R in a portion of the circumferential area in the space between the pair of main body members 22. In this configuration, components such as cables for electrically connecting the device mounted on the vehicle V and the drive unit 1, as well as the holder for the drive unit 1 used when mounting the drive unit 1 on the vehicle V, are arranged through the cover penetration.

[0038] Preferably, the pair of main body members 22 are formed in a plate shape with through holes 225 that penetrate along the reference axis RX. In this embodiment, the main body member 22 is an annular plate-shaped mounting bracket. In the example shown in Figures 4 and 5, the main body member 22 has a main body surface 224 which is a wide surface along the radial direction R. The through holes 225 penetrate the main body surface 224 in the axial direction L. When the main body member 22 is attached to the case 14, the main body surface 224 faces the side wall portion 142 or the cover portion 143 in an axial view L. When the main body member 22 is attached to the case 14, the through holes 225 are positioned on the rotation axis of the output member 12. With this configuration, the main body member 22 does not obstruct the drive connection between the output member 12 and the vehicle-side component (vehicle-side rotating component) that receives the rotational force of the output member 12, so the drive connection structure between the output member 12 and the vehicle-side rotating component can be simplified.

[0039] The outer arrangement portion 221 is an annular shape that extends continuously over the entire circumferential area of ​​the pair of main body members 22. In this embodiment, the main body surface 224 is continuously arranged radially inward R1 relative to the outer arrangement portion 221. The main body members 22 exemplified in Figures 4 and 5 are substantially annular in an axial view L. More specifically, in the examples shown in Figures 4 and 5, the edge of the outer arrangement portion 221 is substantially circular in an axial view L, and the through hole 225 is a circular hole that coincides with the central axis of the main body surface 224. The main body surface 224 exemplified in Figures 4 and 5 is annular. Note that a substantially annular shape includes a strictly annular shape and a shape in which a part of the annular shape is recessed radially inward R1 or protrudes radially outward R2. Similarly, a substantially circular shape also includes a strictly circular shape and a shape in which a part of the circular shape is recessed radially inward R1 or protrudes radially outward R2.

[0040] The sound-insulating cover 25 is formed in a cylindrical shape, connecting a pair of outer mounting portions 221 in the axial direction L. In this embodiment, the sound-insulating cover 25 has an axis along the axial direction L. The entire drive device 1 is housed in the hollow portion of the sound-insulating cover 25. One end of the sound-insulating cover 25 in the axial direction L is fixed to a fixing portion 222 provided on one of the outer mounting portions 221 of the pair of main body members 22. The other end of the sound-insulating cover 25 in the axial direction L is fixed to a fixing portion 222 provided on the other outer mounting portion 221 of the pair of main body members 22. The sound-insulating cover 25 illustrated in Figures 2 and 3 has a substantially cylindrical shape with an axis along the axial direction L. A substantially cylindrical shape includes a strictly cylindrical shape and a shape in which a part of the cylindrical shape is recessed radially inward R1 or protrudes radially outward R2. The sound-insulating cover 25 illustrated in Figures 2 and 3 has a general cylindrical shape and has a flat portion at the top. With this configuration, the space above the drive unit 1 can be effectively utilized, such as by installing vehicle V-side components in the space above the drive unit 1, or by providing a part to hold the drive unit 1 at the top of the drive unit 1.

[0041] In the connecting structure 2 described above, preferably, the mounting portion 24 between the main body 2S and the case 14, as shown in Figure 1, is provided on both the main body member 22 and the case 14. More specifically, as shown in Figures 4 and 5, the mounting portion 24 comprises a first mounting portion 24A provided on the case 14 and a second mounting portion 24B provided on the main body 2S. In this embodiment, the second mounting portion 24B is positioned to overlap with the first mounting portion 24A in an axial view L.

[0042] In this embodiment, the first mounting portion 24A is provided on both the side wall portion 142 and the cover portion 143, and is a fastening hole 241 drilled along the axial direction L. The first mounting portion 24A is provided radially outward R2 from the first opening 14A of the side wall portion 142 and the second opening 14B of the cover portion 143, respectively. The side wall portion 142 and the cover portion 143 are provided with a plurality of first mounting portions 24A. The first mounting portions 24A illustrated in Figure 4 are provided at symmetrical positions with respect to an axis passing through the vertical direction. With this configuration, each of the pair of main body members 22 can be attached to each of the side wall portion 142 and the cover portion 143 without leaving a large gap in the circumferential direction. In addition, the first mounting portion 24A illustrated in Figure 4 is positioned differently from the mounting member 231 in an axial view L. With this configuration, the first mounting portion 24A and the mounting member 231 do not overlap, so the overall structure of the mounting portion 24 is simplified.

[0043] The second mounting portion 24B includes a mounting through portion 243 provided in the main body member 22, and a fastening member 244 that passes through the mounting through portion 243 and fastens the main body member 22 to the side wall portion 142 and the cover portion 143, respectively. The mounting through portion 243 is a through hole that penetrates the main body member 22 in the axial direction L. In this embodiment, a vibration reducing member 245 is arranged between the wall surface surrounding the mounting through portion 243 and the fastening member 244. Therefore, the vibration reducing member 245 supports the fastening member 244 and the case 14 fastened to the fastening member 244, and vibrations of the case 14 are transmitted to the main body member 22 via the vibration reducing member 245. Since the vibration reducing member 245 dampens the vibrations of the case 14, the vibrations transmitted to the main body member 22 are smaller than the vibrations of the case 14.

[0044] In the examples shown in Figures 4 and 5, the mounting through-hole 243 is a circular through-hole in an axial view L, and the fastening member 244 includes a bolt 24X (see Figure 1) and an adapter 24Y for supporting the bolt 24X in the vibration-reducing member 245. The bolt 24X is screwed into the fastening hole 241 through a through-hole that penetrates the rectangular prism-shaped adapter 24Y in the axial direction L. The vibration-reducing member 245 is a cylindrical member that houses the fastening member 244 in its hollow portion. In the examples shown in Figures 4 and 5, the vibration-reducing member 245 houses the adapter 24Y in its hollow portion. Preferably, the entire circumference of the outer surface of the vibration-reducing member 245 is in close contact with the entire circumference of the inner surface of the mounting through-hole 243 when the vibration-reducing member 245 is positioned in the mounting through-hole 243. With this configuration, compared to a configuration in which only a portion of the outer surface of the vibration-reducing member 245 is in close contact with the inner surface of the mounting through-hole 243, it is easier to position the vibration-reducing member 245 in the mounting through-hole 243 so that the surface pressure applied to the outer surface of the vibration-reducing member 245 is of an appropriate magnitude. Therefore, the vibration-reducing member 245 can appropriately reduce the vibrations transmitted from the case 14 to the vibration-reducing member 245. Similarly, it is preferable that the inner surface of the vibration-reducing member 245 is in close contact with the entire outer surface of the fastening member 244 when the fastening member 244 is housed in the hollow portion of the vibration-reducing member 245. In the example shown in Figures 4 and 5, the inner surface of the vibration-reducing member 245 is in close contact with the entire outer surface of the adapter 24Y.

[0045] Preferably, the first mounting portion 24A further includes a boss portion 242 that protrudes from the side wall portion 142 or cover portion 143 toward the corresponding main body member 22. The fastening hole 241 is provided on the surface of the boss portion 242 facing the main body member 22. With this configuration, when the main body member 22 is fixed to the case 14, a gap corresponding to the axial protrusion length L of the boss portion 242 is formed between the side wall portion 142 or cover portion 143 and the main body member 22. Therefore, contact between the main body member 22 and the case 14 can be prevented with a simple structure.

[0046] [Other Embodiments] Next, other embodiments of the electric drive system 100 for vehicles will be described.

[0047] (1) In the above embodiment, the power transmission mechanism 13 was described as comprising a reduction mechanism 131 and a differential gear mechanism 132. However, the power transmission mechanism 13 does not necessarily have to include a reduction mechanism 131 and a differential gear mechanism 132. For example, the power transmission mechanism 13 may be configured to include a stepped transmission, a continuously variable transmission, or other transmission and a differential gear mechanism 132. Note that the differential gear mechanism 132 is not an essential component of the power transmission mechanism 13. For example, like the power transmission mechanism in a wheel motor, the power transmission mechanism 13 may simply be a mechanism for driving and connecting the rotating electric machine 11 and the output member 12.

[0048] (2) In the above embodiment, the main body member 22 was described as a mounting bracket in the shape of a substantially annular plate. However, the shape of the main body member 22 is not limited to a substantially annular plate. For example, the shape of the main body surface 224 of the main body member 22 may correspond to the shape of the side wall portion 142 or the cover portion 143 in an axial view L.

[0049] (3) In the above embodiment, the vibration reducing member 245 was described as being made of a material with a lower modulus of elasticity than the main body 2S. However, the vibration reducing member 245 may also be a vibration absorption mechanism composed of multiple parts. Examples of vibration absorption mechanisms include hydraulic dampers.

[0050] (4) In the above embodiment, the vibration reducing member 245 was described as being located at the mounting portion 24 between the main body 2S of the mounting mechanism 21 and the case 14 in the load transmission path. However, the vibration reducing member 245 may also be located between the main body 2S of the mounting mechanism 21 and the mounting portion 24 in the load path.

[0051] (5) In the above embodiment, the sound insulation cover 25 is supported by the main body 2S of the mounting mechanism 21, and the main body 2S of the mounting mechanism 21 and the sound insulation cover 25 have been described as separate parts. However, the sound insulation cover 25 may be integrally formed with the main body 2S. For example, in such a case, the main body 2S may be made of a material with a lower modulus of elasticity than the case 14. More specifically, when the case 14 is made of metal, the main body 2S may be made of resin. In addition, in a configuration in which the sound insulation cover 25 is integrally formed with the main body 2S, for example, the sound insulation cover 25 may be made into a structure that can be divided into two. In this case, it is preferable to have a structure that allows the two divided sound insulation covers 25 to be fixed to each other while each of the two divided sound insulation covers 25 and the main body 2S, which is integrally formed with each of the two divided sound insulation covers 25, are attached to the case 14. This is because fixing the two divided sound insulation covers 25 to each other can suppress vibration of the two divided sound insulation covers 25 themselves.

[0052] (6) In the above embodiment, the sound insulation cover 25 was described as being directly fixed to the main body member 22 of the mounting mechanism 21. However, the sound insulation cover 25 may be indirectly fixed to the main body member 22 via other parts. In particular, it is preferable that the sound insulation cover 25 be fixed to the main body member 22 via a vibration reduction member 245. With this configuration, vibrations transmitted from the main body member 22 to the sound insulation cover 25 can be reduced, thereby further improving the sound insulation performance of the sound insulation cover 25.

[0053] (7) In the above embodiment, the sound insulation cover 25 covers the entire circumference of the side wall portion 142, the peripheral wall portion 141, and the cover portion 143 of the case 14 from the radially outward R2, and the side wall portion 142 and the cover portion 143 are not covered by the sound insulation cover 25 from either side in the axial direction L. However, the extent to which the sound insulation cover 25 covers the case 14 is not limited to the above embodiment. For example, noise generated from the vehicle electric drive unit 100 is often a problem because it propagates into the passenger compartment of the vehicle V and reaches the occupants inside the passenger compartment. For this reason, if the positional relationship between the passenger compartment of the vehicle V and the vehicle electric drive unit 100 is predetermined, the sound insulation cover 25 may be placed only between the case 14 and the passenger compartment. With this configuration, since only a part of the outer surface of the case 14 is covered by the sound insulation cover 25, it is easy to reduce the overall size of the vehicle electric drive unit 100.

[0054] (8) In the above embodiment, the pair of main body members 22 were described as being arranged to sandwich the case 14 from both sides in the axial direction L. However, the pair of main body members 22 may be arranged to sandwich the case 14 from both sides in the radially outer direction R2. More specifically, for example, the pair of main body members 22 may be arranged to sandwich the case 14 from the top and bottom direction, or to sandwich the case 14 from the width direction perpendicular to the axial direction L when viewed from the top and bottom direction.

[0055] (9) In the above embodiment, it was explained that the rotation axis of the output member 12 and the rotation axis of the rotating electric machine 11 are coaxial. However, the rotation axis of the output member 12 may be positioned parallel to the rotation axis of the rotating electric machine 11. Alternatively, the rotation axis of the output member 12 may be positioned at a point where it intersects with the rotation axis of the rotating electric machine 11. Note that positioning the rotation axis of the output member 12 at a point where it intersects with the rotation axis of the rotating electric machine 11 includes cases where the rotation axis of the output member 12 and the rotation axis of the rotating electric machine 11 are in a torsional positional relationship.

[0056] (10) In the above embodiment, an upper mount 232 is attached to each of the pair of main body members 22, and a torque mount 233 is attached to one of the main body members 22. However, the type and number of mount members 231 attached to the pair of main body members 22 are not limited to the above.

[0057] (11) In the above embodiment, the outer arrangement portion 221 was described as being provided around the entire circumference of the main body member 22 in the circumferential direction. However, the outer arrangement portion 221 may be provided only on a part of the main body member 22 in the circumferential direction. For example, if the positional relationship between the drive unit 1 and the passenger compartment is fixed, the outer arrangement portion 221 may be provided on the main body member 22 so that the sound insulation cover 25 can be attached only in the area between the drive unit 1 and the passenger compartment where the sound insulation cover 25 can be placed.

[0058] (12) In the above embodiment, the sound insulation cover 25 was described as being substantially cylindrical in shape. However, the sound insulation cover 25 is not limited to being substantially cylindrical in shape as long as the drive device 1 can be housed in the space surrounded by the sound insulation cover 25 and the pair of main body members 22. For example, the sound insulation cover 25 may be cylindrical in shape with a cross-sectional shape corresponding to the shape of the outer arrangement portion 221 in an axial view L.

[0059] (13) In the above embodiment, the sound insulation cover 25 was described as being formed in a cylindrical shape. However, the sound insulation cover 25 may have a segmented structure comprising a plurality of segments. Figure 6 illustrates a sound insulation cover 25 that can be segmented vertically. Specifically, the sound insulation cover 25 shown in Figure 6 is segmented into a first segment 25A and a second segment 25B. The first segment 25A is segmented upwards, and the second segment 25B is segmented downwards. With this configuration, when the sound insulation cover 25 is positioned to cover the outer surface of the case 14, the first segment 25A and the second segment 25B can be positioned sequentially in predetermined locations. Therefore, the worker can perform the task of positioning the sound insulation cover 25 in predetermined locations while securing a relatively large workspace. Although Figure 6 shows an example in which the sound insulation cover 25 is segmented vertically, the segmentation direction of the sound insulation cover 25 is not limited to the vertical direction. For example, the sound insulation cover 25 may be segmented in the axial direction L.

[0060] (14) The configurations disclosed in the embodiments described above can be applied in combination with configurations disclosed in other embodiments, as long as no inconsistencies arise. With regard to other configurations, the embodiments disclosed herein are merely illustrative in all respects. Therefore, various modifications can be made as appropriate without departing from the spirit of this disclosure.

[0061] [Summary of this embodiment] The following is a summary of the embodiments relating to the electric drive system (100) for vehicles described above.

[0062] The electric drive system for vehicles includes a rotating electric machine (11) and An output member (12) is driven and connected to the wheels (WH) of the vehicle (V), A power transmission mechanism (13) that transmits driving force between the rotating electric machine (11) and the output member (12), A case (14) housing the rotating electric machine (11) and the power transmission mechanism (13), A mounting mechanism (21) for attaching the case (14) to the vehicle (V), Soundproof cover (25), A vehicle electric drive system (100) equipped with, The mounting mechanism (21) comprises a main body (2S) supported by the vehicle (V), and a vibration reducing member (245) disposed at the mounting portion (24) between the main body (2S) and the case (14) to reduce vibrations transmitted through the mounting portion (24). The sound-insulating cover (25) is supported by the main body (2S) and is positioned to cover the case (14) without contacting the case (14).

[0063] With this configuration, the sound insulation cover (25) covers the case (14) without contacting the case (14), and a vibration reduction member (245) is positioned at the mounting portion (24) between the main body (2S) of the mounting mechanism (21) and the case (14). Therefore, vibrations transmitted from the rotating electric machine (11) and the power transmission mechanism (13) to the sound insulation cover (25) can be reduced. Consequently, the sound insulation cover (25) can cover the case (14) while preventing the sound insulation cover (25) itself from becoming a noise source due to vibration, thereby improving the sound insulation performance of the sound insulation cover (25). In addition, the need to provide the sound insulation cover (25) with functions other than sound insulation, such as vibration reduction, can be reduced, making it easier to increase the design flexibility of the sound insulation cover (25), and consequently, easier to improve the sound insulation performance of the electric drive system (100) for vehicles.

[0064] Here, the mounting mechanism (21) comprises a pair of main body members (22) arranged to face each other with the case (14) in between, as the main body portion (2S). Preferably, the sound-insulating cover (25) is arranged to connect the pair of main body members (22).

[0065] With this configuration, the case (14) can be efficiently covered by a pair of main body members (22) and a sound-insulating cover (25). Therefore, it is easy to improve sound insulation while simplifying the shape of the sound-insulating cover (25).

[0066] Furthermore, in a configuration in which the mounting mechanism (21) comprises a pair of main body members (22) arranged to face each other with the case (14) in between, and the sound insulation cover (25) is arranged to connect the pair of main body members (22), The rotation axis of either the rotating electric machine (11) or the output member (12) is defined as the reference axis (RX), the direction along the reference axis (RX) is defined as the axial direction (L), and the direction perpendicular to the reference axis (RX) is defined as the radial direction (R). The pair of main body members (22) are arranged to sandwich the case (14) from both sides in the axial direction (L), In an axial view along the axial direction (L), at least a portion of the outer edge of the pair of main body members (22) is provided with an outer arrangement portion (221) that is positioned radially (R) further out than the outer edge of the case (14). Preferably, the sound-insulating cover (25) is arranged so as to connect the outer arrangement portions (221) of each of the pair of main body members (22) in the axial direction (L).

[0067] This configuration allows for the sound insulation cover (25) to be positioned to cover the case (14) without coming into contact with it, while also making it easier to further simplify the shape of the sound insulation cover (25).

[0068] Furthermore, in a configuration in which a pair of main body members (22) are arranged to sandwich the case (14) from both sides in the axial direction (L), and in an axial view (L), at least a portion of the outer edge of the pair of main body members (22) is provided with an outer arrangement portion (221) that is located radially (R) further out than the outer edge of the case (14), and the sound insulation cover (25) is arranged to connect the respective outer arrangement portions (221) of the pair of main body members (22) in the axial direction (L), The aforementioned reference axis (RX) is the rotation axis of the output member (12), The pair of main body members (22) are formed in a plate shape and have through holes (225) that penetrate along the reference axis (RX), The direction in which the rotation occurs around the aforementioned reference axis (RX) is defined as the circumferential direction. The outer arrangement portion (221) is an annular shape that extends continuously over the entire circumferential area of ​​the pair of main body members (22). The sound-insulating cover (25) is preferably formed in a cylindrical shape that connects a pair of the outer arrangement portions (221) in the axial direction (L).

[0069] This configuration allows for easy drive connection between the output member (12) and the wheel (WH) by providing a through hole (225) that penetrates along the reference axis (RX), while the case (14) can be properly supported by a pair of main body members (22). Furthermore, it facilitates further simplification of the shape of the sound insulation cover (25). [Industrial applicability]

[0070] The technology disclosed herein can be used in electric drive systems for vehicles that are mounted on vehicles. [Explanation of symbols]

[0071] 11: Rotating electric machine, 12: Output member, 13: Power transmission mechanism, 14: Case, 21: Mounting mechanism, 22: Main body member, 24: Mounting part, 25: Sound insulation cover, 2S: Main body part, 100: Electric drive unit for vehicle, 221: Outer arrangement part, 225: Through hole, 245: Vibration reduction member, L: Axial direction, R: Radial direction, RX: Reference axis, V: Vehicle, WH: Wheel

Claims

1. Rotating electric machines and, An output member that is driven and connected to the vehicle's wheels, A power transmission mechanism that transmits driving force between the rotating electric machine and the output member, A case housing the aforementioned rotating electric machine and the aforementioned power transmission mechanism, A mounting mechanism for attaching the case to the vehicle, Soundproof cover and, An electric drive system for a vehicle, comprising: The mounting mechanism comprises a main body supported by the vehicle, and a vibration reducing member disposed at the mounting portion between the main body and the case to reduce vibrations transmitted through the mounting portion. The sound-insulating cover is supported by the main body and is positioned to cover the case without contacting the case, in an electric drive device for a vehicle.

2. The mounting mechanism comprises a pair of main body members arranged to face each other across the case, The electric drive device for a vehicle according to claim 1, wherein the sound-insulating cover is arranged to connect a pair of the main body members.

3. The rotation axis of either the rotating electric machine or the output member is defined as the reference axis, the direction along the reference axis is defined as the axial direction, and the direction perpendicular to the reference axis is defined as the radial direction. The pair of main body members are arranged to sandwich the case from both sides in the axial direction. In an axial view along the axial direction, at least a portion of the outer edge of the pair of main body members is provided with an outer arrangement portion that is positioned radially outward from the outer edge of the case. The electric drive device for a vehicle according to claim 2, wherein the sound-insulating cover is arranged to connect the outer arrangement portions of each of the pair of main body members in the axial direction.

4. The aforementioned reference axis is the rotation axis of the output member, The pair of main body members are formed in a plate shape with through holes that penetrate along the reference axis, The direction in which the rotation occurs around the aforementioned reference axis is defined as the circumferential direction. The outer arrangement portion is an annular shape that extends continuously over the entire circumferential area of ​​the pair of main body members. The electric drive device for a vehicle according to claim 3, wherein the sound-insulating cover is formed in a cylindrical shape that connects the pair of outer arrangement parts in the axial direction.

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