Vibration dampening device for electric motor

Abstract

Provided is a vibration dampening device for an electric motor with a novel structure capable of achieving additional quietness by more highly dampening vibration caused by the electric motor.　The vibration dampening device 10 for an electric motor, which connects an electric motor 38 and a vehicle body 40 in a vibration dampening manner, comprises a mass member 16 provided with a motor-side vibration dampening support part 12 attached to an electric motor 38 side and a body-side vibration dampening support part 14 attached to a vehicle body 40 side, and a primary resonance frequency of a vibration system constituted of the mass member 16 elastically supported by the motor-side vibration dampening support part 12 and the body-side vibration dampening support part 14 is tuned to a frequency lower than the frequency of to-be-dampened-vibration caused by the electric motor 38.

Description

Vibration Isolation Device for Electric Motor

[0005]

[0001] The present invention relates to a vibration isolation device for an electric motor used for vibration isolation support of an electric motor in a vehicle.

[0002] Conventionally, a vibration isolation device for vibration isolation support of a power unit in an automobile has been known. The vibration isolation device reduces the transmission of vibration from the power unit to the vehicle body, for example, by disposing an elastic body on the vibration transmission path from the power unit to the vehicle body, as disclosed in Japanese Patent Application Laid-Open No. 2018-062976 (Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2018-062976

[0004] By the way, in recent automobiles, electrification using an electric motor instead of an internal combustion engine (engine) in the power unit has been rapidly progressing. And, due to the electrification of the power unit, the quietness of the automobile has been greatly improved. As a result, vibrations (noises) at a level that did not pose a problem in conventional engine vehicles have newly become a problem.

[0005] However, since the motor mount is not necessarily designed specifically, and in some cases, for example, a conventional engine mount as in Patent Document 1 is being used, further improvement in vibration isolation performance has been demanded. In particular, in an electrified vehicle using an electric motor, vibrations at a higher frequency than those that did not pose a problem in conventional engine vehicles have become a problem. Therefore, better vibration isolation performance against vibrations in the high-frequency range peculiar to the motor mount is required.

[0006] The problem to be solved by the present invention is to provide a vibration isolation device for an electric motor with a novel structure that can more highly isolate vibrations caused by the electric motor and achieve further quietness.

[0007] The following describes preferred embodiments for understanding the present invention. However, each embodiment described below is illustrative and can be combined with others as appropriate. Furthermore, the multiple components described in each embodiment can be recognized and adopted as independently as possible, and can be combined with any component described in another embodiment as appropriate. Thus, the present invention is not limited to the embodiments described below, and various other embodiments can be realized.

[0008] The first embodiment is a vibration isolation device for an electric motor that vibrationally connects the electric motor and the vehicle body, wherein a motor-side vibration isolation support attached to the electric motor side and a body-side vibration isolation support attached to the vehicle body side are provided on a mass member, and the primary resonant frequency of the sub-vibration system formed by the mass member elastically supported by the motor-side vibration isolation support and the body-side vibration isolation support is tuned to a lower frequency than the frequency of the vibration to be isolated caused by the electric motor.

[0009] According to the vibration isolation device for electric motors with a structure conforming to this embodiment, two vibration isolation structures, a motor-side vibration isolation support and a body-side vibration isolation support, can be arranged along the vibration transmission path from the electric motor to the vehicle body. The high vibration isolation performance provided by such a double vibration isolation structure enables more advanced vibration isolation against vibrations caused by the operation of the electric motor, etc., and further quietness can be achieved in electric vehicles, which are already known for their quietness.

[0010] In particular, by constructing a vibration system using a mass member, a motor-side vibration isolation support, and a body-side vibration isolation support, a significant reduction in vibration transmission coefficient can be achieved in the frequency range higher than the primary resonant frequency of the vibration system. Therefore, by tuning the primary resonant frequency of the vibration system to a lower frequency than the frequency of the vibration to be isolated, caused by the operation of the electric motor, etc., the transmission of the vibration to be isolated to the vehicle body can be suppressed more effectively.

[0011] The second embodiment is a vibration isolation device for an electric motor as described in the first embodiment, wherein the ratio of the static support load of the mass member exerted on the motor-side vibration isolation support portion to the static support load of the mass member exerted on the body-side vibration isolation support portion is within the range of 80% to 120%.

[0012] According to the vibration isolation device for electric motors constructed in accordance with this embodiment, the static support load of the mass member is evenly distributed between the motor-side vibration isolation support and the body-side vibration isolation support. As a result, the mass member is stably supported, and the durability of both the motor-side and body-side vibration isolation support is improved. Furthermore, it becomes easier to adopt a common structure for both the motor-side and body-side vibration isolation support.

[0013] A third embodiment is a vibration isolation device for an electric motor as described in the first or second embodiment, wherein the motor-side vibration isolation support portion and the body-side vibration isolation support portion each have a structure in which an inner shaft member is inserted into a mounting hole formed in the mass member, an elastic body is disposed between the outer circumferential surface of the inner shaft member and the inner surface of the mounting hole, and the inner shaft member and the mass member are mutually connected by the elastic body.

[0014] According to the vibration isolation device for electric motors with a structure conforming to this embodiment, the motor-side vibration isolation support and the body-side vibration isolation support are both cylindrical vibration isolation devices, thereby enabling the desired vibration isolation performance to be achieved with a simple structure.

[0015] A fourth aspect is a vibration damping device for an electric motor as described in the third aspect, wherein a flange-like portion is provided at the axial end of the inner shaft member that protrudes outward, an adjustment rubber is disposed between the axially opposing surfaces of the opening periphery of the mounting hole in the mass member and the flange-like portion, and a tuning mechanism is provided that adjusts the primary resonant frequency of the vibration system by tightening the adjustment rubber between the mass member and the flange-like portion.

[0016] According to the vibration isolation device for electric motors with a structure conforming to this embodiment, the primary resonant frequency of the vibration system can be set to a lower frequency than the frequency of the vibration to be isolated by appropriately adjusting the tightening amount of the adjustment rubber. Therefore, for example, while standardizing the structure of a cylindrical vibration isolation device in which an inner shaft member and a mass member are connected by an elastic body, the resonant frequency of the vibration system can be tuned according to the vibration to be isolated.

[0017] The fifth aspect is a vibration damping device for an electric motor as described in the third or fourth aspect, wherein the mounting hole in which the motor-side vibration damping support is provided and the mounting hole in which the body-side vibration damping support is provided extend parallel to each other.

[0018] According to the vibration isolation device for electric motors with a structure conforming to this embodiment, by mounting cylindrical vibration isolation devices in mounting holes that are parallel to each other, motor-side vibration isolation support parts and body-side vibration isolation support parts with similar characteristics can be provided on the mass member.

[0019] The sixth aspect is a vibration damping device for an electric motor as described in the third or fourth aspect, wherein the mass member comprises a first plate-like portion in which the mounting hole for which the motor-side vibration damping support portion is provided penetrates in the plate thickness direction, and a second plate-like portion in which the mounting hole for which the body-side vibration damping support portion is provided is provided, wherein the plate thickness direction of the first plate-like portion and the plate thickness direction of the second plate-like portion are in different directions from each other.

[0020] According to the vibration isolation device for an electric motor with a structure conforming to this embodiment, the motor-side vibration isolation support portion can be positioned in an orientation suitable for the mounting structure on the electric motor side, while the body-side vibration isolation support portion can be positioned in an orientation suitable for the mounting structure on the vehicle body side.

[0021] The seventh embodiment is a vibration isolation device for an electric motor described in any one of the first to sixth embodiments, wherein one motor-side vibration isolation support and one body-side vibration isolation support are provided.

[0022] According to the vibration isolation device for electric motors with a structure conforming to this embodiment, by supporting the mass member with fewer support points, the displacement of the mass member during vibration input is stabilized, and the desired vibration isolation performance can be reliably obtained.

[0023] The eighth aspect is a vibration isolation device for an electric motor as described in the seventh aspect, wherein the center of gravity of the mass member, the elastic center of the motor-side vibration isolation support, and the elastic center of the body-side vibration isolation support are located on the same straight line.

[0024] According to the vibration isolation device for electric motors with a structure conforming to this embodiment, the displacement pattern of the mass member during vibration input is stable, making it less likely for the mass member to undergo unintended displacements such as swaying, and thus the desired vibration isolation performance can be reliably obtained.

[0025] According to the present invention, vibrations caused by electric motors can be suppressed to a higher degree, thereby achieving even greater quietness.

[0026] A perspective view showing a vibration damping device for an electric motor as the first embodiment of the present invention. A front view of the vibration damping device for an electric motor shown in Figure 1. A right side view of the vibration damping device for an electric motor shown in Figure 1. A cross-sectional view of the IV-IV section of Figure 3. A perspective view showing a vibration damping device for an electric motor as the second embodiment of the present invention. A right side view of the vibration damping device for an electric motor shown in Figure 5. A perspective view showing a vibration damping device for an electric motor as the third embodiment of the present invention. A perspective view showing a vibration damping device for an electric motor as the fourth embodiment of the present invention. A cross-sectional view of the vibration damping device for an electric motor shown in Figure 8, which corresponds to the IX-IX section of Figure 10, and is the X-X section of Figure 9.

[0027] Embodiments of the present invention will be described below with reference to the drawings.

[0028] Figures 1 to 4 show a motor mount 10 for an automobile as a first embodiment of the vibration damping device for an electric motor according to the present invention. The motor mount 10 is used to vibration-dampe the electric motor 38 (described later) and the vehicle body 40, and has a structure in which a motor-side vibration damping support part 12 attached to the electric motor 38 side (described later) and a body-side vibration damping support part 14 attached to the vehicle body 40 side (described later) are provided on a mass member 16. In the following description, as a general rule, the vertical direction refers to the vertical direction in Figure 2, the left-right direction refers to the left-right direction in Figure 2, and the front-rear direction refers to the left-right direction in Figure 3.

[0029] The motor-side vibration-damping support section 12 has a structure in which a first elastic body 20 is fixed to a first inner shaft member 18, which serves as an inner shaft member. The first inner shaft member 18 is a small-diameter, substantially cylindrical shape and has a bolt hole 22 that penetrates it in the axial direction. The first inner shaft member 18 is a rigid member made of metal, fiber-reinforced synthetic resin, or the like.

[0030] The first elastic body 20 is substantially cylindrical in shape, and its inner circumferential surface is fixed to the outer circumferential surface of the first inner shaft member 18. The first elastic body 20 is, for example, vulcanized and bonded to the first inner shaft member 18 during molding. The axial dimension of the first elastic body 20 is smaller than the axial dimension of the first inner shaft member 18, and the first inner shaft member 18 protrudes from the first elastic body 20 on both axial sides. A continuous groove 24 is opened around the entire circumference of the outer circumferential surface of the first elastic body 20.

[0031] The body-side vibration-damping support section 14 has a structure in which a second elastic body 28 is fixed to a second inner shaft member 26, which serves as an inner shaft member. The second inner shaft member 26 is substantially the same as the first inner shaft member 18 and is provided with a bolt hole 22 that penetrates in the axial direction.

[0032] The second elastic body 28 is substantially cylindrical in shape, and its inner circumferential surface is fixed to the outer circumferential surface of the second inner shaft member 26. For example, it is vulcanized and bonded to the second inner shaft member 26 during molding. The second elastic body 28 is substantially the same as the first elastic body 20, and a groove 24 opening to the outer circumferential surface is formed around its entire circumference.

[0033] In this embodiment, the motor-side vibration-damping support part 12 and the body-side vibration-damping support part 14 are substantially the same shape and size, and the parts of the motor-side vibration-damping support part 12 and the body-side vibration-damping support part 14 are standardized.

[0034] The mass member 16 is made of a metal such as iron or an aluminum alloy. The mass member 16 integrally comprises a first plate-like portion 30 and a second plate-like portion 32. The first plate-like portion 30 and the second plate-like portion 32 are both thick plates, and their thickness directions are oriented approximately perpendicular to each other.

[0035] The first plate-like portion 30 has a substantially constant front-to-back thickness dimension. The first plate-like portion 30 has a first mounting hole 34 with a circular cross-section that penetrates in the plate thickness direction (front-to-back direction). The lower part of the first plate-like portion 30 has a width dimension that increases from left to right towards the top, the upper and lower intermediate part extends vertically with a substantially constant width dimension, and the upper part has a width dimension that decreases from left to right towards the top. The rate of change of the width dimension of the lower part of the first plate-like portion 30 is substantially constant, while the rate of change of the width dimension of the upper part increases as it goes upward.

[0036] The second plate-like portion 32 has a substantially constant left-right thickness dimension. The second plate-like portion 32 has a second mounting hole 36 with a circular cross-section that penetrates in the thickness direction (left-right direction). The upper part of the second plate-like portion 32 has a front-to-back width dimension that increases downwards, the upper and lower intermediate part extends vertically with a substantially constant width dimension, and the lower part has a decreasing left-to-right width dimension that decreases downwards. The rate of change in the width dimension of the upper part of the second plate-like portion 32 is substantially constant, while the rate of change in the width dimension of the lower part increases as it goes downwards.

[0037] The first plate-like portion 30 and the second plate-like portion 32 have different thickness directions, and the first mounting hole 34 and the second mounting hole 36 extend in different directions. In this embodiment, the thickness direction of the first plate-like portion 30 is the left-right direction, and the thickness direction of the second plate-like portion 32 is the front-rear direction, the first mounting hole 34 penetrates the first plate-like portion 30 in the left-right direction, and the second mounting hole 36 penetrates the second plate-like portion 32 in the front-rear direction.

[0038] In this embodiment, the first plate-like portion 30 and the second plate-like portion 32 are substantially the same shape and size, and are arranged so that their thickness directions are substantially perpendicular to each other. Furthermore, the connecting portion between the first plate-like portion 30 and the second plate-like portion 32 has a substantially square cross-sectional shape perpendicular to the vertical direction.

[0039] The mass member 16 is provided with a motor-side vibration damping support portion 12. Specifically, the first elastic body 20, fixed to the first inner shaft member 18, is inserted into the first mounting hole 34, and the peripheral wall portion of the first mounting hole 34 fits into the groove 24 of the first elastic body 20, thereby attaching the first elastic body 20 to the mass member 16, and the motor-side vibration damping support portion 12 is provided on the upper part of the mass member 16. In other words, the first inner shaft member 18 is inserted through the first mounting hole 34, and the first elastic body 20 is positioned between the first inner shaft member 18 and the mass member 16 (the peripheral wall portion of the first mounting hole 34), so that the first inner shaft member 18 and the mass member 16 are elastically connected by the first elastic body 20, and the motor-side vibration damping support portion 12 is provided on the upper part of the mass member 16. The first elastic body 20 may be fitted into the first mounting hole 34 without adhesive, or it may be bonded. Furthermore, it is desirable that the first elastic body 20 is compressed radially between the first inner shaft member 18 and the mass member 16 when inserted into the first mounting hole 34.

[0040] The mass member 16 is provided with a body-side vibration damping support portion 14. Specifically, the second elastic body 28, fixed to the second inner shaft member 26, is inserted into the second mounting hole 36, and the peripheral wall portion of the second mounting hole 36 fits into the groove 24 of the second elastic body 28, thereby attaching the second elastic body 28 to the mass member 16, and the body-side vibration damping support portion 14 is provided at the lower part of the mass member 16. In other words, the second inner shaft member 26 is inserted through the second mounting hole 36, and the second elastic body 28 is positioned between the second inner shaft member 26 and the mass member 16 (the peripheral wall portion of the second mounting hole 36), so that the second inner shaft member 26 and the mass member 16 are elastically connected by the second elastic body 28, and the body-side vibration damping support portion 14 is provided at the lower part of the mass member 16. The second elastic body 28 may be fitted into the second mounting hole 36 without adhesive, or it may be bonded. Furthermore, it is desirable that the second elastic body 28 is compressed radially between the second inner shaft member 26 and the mass member 16 when inserted into the second mounting hole 36.

[0041] In this embodiment, the motor mount 10 has one motor-side vibration-damping support portion 12 provided on the upper part of the mass member 16, and one body-side vibration-damping support portion 14 provided on the lower part of the mass member 16, with one motor-side vibration-damping support portion 12 and one body-side vibration-damping support portion 14 each positioned at both ends of the mass member 16 in the vertical direction, which is the longitudinal direction.

[0042] The motor mount 10, having the structure described above, is mounted on the vehicle by having the first inner shaft member 18 attached to the electric motor 38 and the second inner shaft member 26 attached to the vehicle body 40. When the motor mount 10 is mounted on the vehicle, the electric motor 38 is vibration-damped and supported by the vehicle body 40.

[0043] In the vehicle-mounted state of the motor mount 10, the static support load of the mass member 16 acting on the motor-side vibration-damping support part 12 is preferably in the range of 80% to 120%, and more preferably in the range of 90% to 110%, of the static support load of the mass member 16 acting on the body-side vibration-damping support part 14. In short, it is desirable that the support load of the mass member 16 acts evenly distributed between the motor-side vibration-damping support part 12 and the body-side vibration-damping support part 14 without being significantly biased toward either one.

[0044] In addition, in the present embodiment, the first plate-like portion 30 and the second plate-like portion 32 have substantially the same shape and size as each other, and are arranged in directions substantially orthogonal to each other. The motor-side vibration isolation support portion 12 and the body-side vibration isolation support portion 14 have substantially the same shape and size as each other. Therefore, either the motor-side vibration isolation support portion 12 or the body-side vibration isolation support portion 14 may be attached to the motor side. In short, in the present embodiment, the motor-side vibration isolation support portion 12 and the body-side vibration isolation support portion 14 are merely distinguished for convenience of explanation, and either of the two vibration isolation support portions 12 and 14 provided on the mass member 16 may be attached to the motor side. Therefore, when the motor mount 10 of the present embodiment is attached to the vehicle, the orientation can be easily specified, and the attachment work to the vehicle is simple. In addition, the two vibration isolation support portions 12 and 14 provided on the mass member 16 have substantially the same mass as each other, so that the vibration mode is stabilized, and it is also effective for substantially equalizing the static shared support loads of the mass member 16 on the motor-side vibration isolation support portion 12 and the body-side vibration isolation support portion 14.

[0045] On the vibration transmission path through the motor mount 10 between the electric motor 38 and the vehicle body 40, the first elastic body 20 and the second elastic body 28 are arranged in series. Therefore, both the vibration isolation effect exerted by the elastic deformation of the first elastic body 20 and the vibration isolation effect exerted by the elastic deformation of the second elastic body 28 can be obtained, and excellent vibration isolation performance by double vibration isolation is realized. In particular, it is not a support structure of a power unit via a subframe such as a conventional vibration isolation support structure of an internal combustion engine, but a structure in which the electric motor 38 is directly vibration isolation supported via the motor mount 10 with respect to the main body of the vehicle body 40 having a monocoque structure. Even in this case, a double vibration isolation mechanism can be realized efficiently and compactly, and excellent vibration isolation performance can be obtained.

[0046] Further, the mass member 16 is elastically supported by a motor-side anti-vibration support portion 12 attached to the electric motor 38 and a body-side anti-vibration support portion 14 attached to the vehicle body 40. Therefore, when the motor mount 10 is mounted on the vehicle, a vibration system 42 is configured on the vibration transmission path from the electric motor 38 to the vehicle body 40, with the mass member 16 as the mass component and the motor-side anti-vibration support portion 12 and the body-side anti-vibration support portion 14 (the first and second elastic bodies 20, 28) as the spring components. When vibration input at a frequency higher than the primary resonance frequency of the vibration system 42 occurs, due to the anti-resonance of the vibration system 42, the displacement of the mass member 16 becomes extremely small, and the vibration transmission rate from the electric motor 38 side to the vehicle body 40 side decreases. Therefore, by tuning the primary resonance frequency of the vibration system 42 to a lower frequency than, for example, the vibration to be isolated such as the high-frequency vibration generated during the operation of the electric motor 38, the transmission of the vibration to be isolated to the vehicle body 40 side is effectively suppressed. Thus, according to the motor mount 10 for an electric motor, it is possible to exhibit excellent anti-vibration performance against the vibrations peculiar to the electric motor 38, and a higher anti-vibration effect can be obtained compared to the case where, for example, a conventional engine mount is diverted and used as a motor mount. The primary resonance frequency of the vibration system 42 can be appropriately adjusted and set according to the mass of the mass member 16 and the spring characteristics of the first and second elastic bodies 20, 28.

[0047] The center of gravity G of the mass member 16, the elastic center C1 of the motor-side anti-vibration support portion 12 (the first elastic body 20), and the elastic center C2 of the body-side anti-vibration support portion 14 (the second elastic body 28) are located on one straight line L (the dashed-dotted line in FIG. 4) extending in the vertical direction. Thereby, when vibration is input, the displacement of the mass member 16 elastically supported by the motor-side anti-vibration support portion 12 and the body-side anti-vibration support portion 14 is stabilized, and an efficient improvement in the vibration state can be expected.

[0048] FIGS. 5 and 6 show a motor mount 50 for an automobile as a second embodiment of the anti-vibration device for an electric motor according to the present invention. In the following description, members and parts that are substantially the same as those in the first embodiment are denoted by the same reference numerals in the drawings, and the description thereof is omitted.

[0049] The motor mount 50 has a motor-side vibration isolation support portion 52 that has a different structure from the body-side vibration isolation support portion 14, which has the same structure as in the first embodiment. The motor-side vibration isolation support portion 52 has a structure in which a first inner shaft member 18 and a first outer cylindrical member 54 are mutually connected by a first elastic body 56.

[0050] The first outer cylindrical member 54 has a roughly cylindrical shape with a thinner wall and larger diameter compared to the first inner shaft member 18. The first outer cylindrical member 54 is a rigid member made of the same material as the first inner shaft member 18. The axial length dimension of the first outer cylindrical member 54 is smaller than the axial length dimension of the first inner shaft member 18, and is the same as or larger than the plate thickness dimension of the first plate-like portion 30 in the mass member 16.

[0051] The first elastic body 56 is provided with a pair of recessed holes 58, 58 on both the upper and lower sides of the first inner shaft member 18. The recessed holes 58, 58 penetrate the first elastic body 56 in the axial direction. The recessed holes 58, 58 have a cross-sectional shape that extends circumferentially on both the upper and lower sides of the first inner shaft member 18. By forming the pair of recessed holes 58, 58, the first elastic body 56 has a pair of rubber arms 60, 60 that extend approximately left and right between the upper and lower recessed holes 58, 58. In addition, stopper rubbers 62, 62 are formed on the upper and lower outer sides of the pair of recessed holes 58, 58. With this structure, the spring constant in the vertical direction of the first elastic body 56 is smaller than the spring constant in the left and right direction.

[0052] The first elastic body 56 may be inserted separately between the first inner shaft member 18 and the first outer cylindrical member 54, but preferably it is formed as an integrally vulcanized molded product comprising the first inner shaft member 18 and the first outer cylindrical member 54. Furthermore, if the first elastic body 56 is vulcanized and bonded to the first inner shaft member 18 and the first outer cylindrical member 54, it is desirable to reduce the tensile stress of the first elastic body 56 due to thermal shrinkage after molding by reducing the diameter of the first outer cylindrical member 54 after vulcanization molding.

[0053] The motor-side vibration damping support 52 is provided on the mass member 16 by press-fitting the first outer cylindrical member 54 into the first mounting hole 34 of the mass member 16. The motor-side vibration damping support 52 is mounted on the mass member 16 in a direction such that a pair of cut holes 58, 58 are located on both the upper and lower sides relative to the first inner shaft member 18. In short, the motor-side vibration damping support 52 of this embodiment requires circumferential positioning relative to the mass member 16 compared to the motor-side vibration damping support 12 of the first embodiment. In other words, the motor-side vibration damping support 12 and the body-side vibration damping support 14 of the first embodiment do not require circumferential positioning relative to the mass member 16.

[0054] According to the motor mount 50 of this embodiment, the soft spring characteristics of the motor-side vibration-damping support portion 52 in the vertical direction provide superior vibration isolation against vertical vibrations, thereby more effectively suppressing the transmission of vibrations to be damped, such as high-frequency, small-amplitude vibrations caused by the operation of the electric motor 38.

[0055] Furthermore, when a large vertical load is applied between the first inner shaft member 18 and the first outer cylindrical member 54, the first inner shaft member 18 and the first outer cylindrical member 54 come into contact with each other cushioningly via the stopper rubbers 62, 62, thereby limiting the relative displacement between the first inner shaft member 18 and the first outer cylindrical member 54. Therefore, excessive deformation of the first elastic body 56 is prevented, and the durability of the first elastic body 56 is ensured.

[0056] Furthermore, a structure similar to that of the motor-side vibration damping support 52 in this embodiment can also be applied to the body-side vibration damping support.

[0057] Figure 7 shows a motor mount 70 for an automobile as a third embodiment of the vibration isolation device for electric motors according to the present invention. The motor mount 70 has a structure in which a motor-side vibration isolation support portion 12 and a body-side vibration isolation support portion 14 are attached to a mass member 72.

[0058] The mass member 72 integrally comprises a first plate-shaped portion 30 on which the motor-side vibration-damping support portion 12 is provided, and a second plate-shaped portion 74 on which the body-side vibration-damping support portion 14 is provided. In this embodiment, the first plate-shaped portion 30 and the second plate-shaped portion 74 have substantially the same thickness direction relative to each other. As a result, the mass member 72 as a whole is a single plate-shaped object.

[0059] The first plate-like portion 30 has a lower left-right width dimension that increases upwards, an upper and lower intermediate portion that extends vertically with a substantially constant width dimension, and an upper left-right width dimension that decreases upwards. The second plate-like portion 74 has an upper left-right width dimension that increases downwards, an upper and lower intermediate portion that extends vertically with a substantially constant width dimension, and an lower left-right width dimension that decreases downwards. In short, the second plate-like portion 74 is substantially vertically symmetrical with respect to the first plate-like portion 30. The mass member 72 has an hourglass-shaped constriction when viewed from the left to right, with the front-to-back width dimension of the upper and lower central portion being reduced.

[0060] In this embodiment, the mass member 72 has a first plate-like portion 30 and a second plate-like portion 74 whose thickness directions are circumferential. As a result, the first mounting hole 34 that penetrates the first plate-like portion 30 in the thickness direction and the second mounting hole 36 that penetrates the second plate-like portion 74 in the thickness direction extend substantially parallel to each other in the same direction (left-right direction). The motor-side vibration damping support portion 12 that is mounted in the first mounting hole 34 of the first plate-like portion 30 and the body-side vibration damping support portion 14 that is mounted in the second mounting hole 36 of the second plate-like portion 74 extend substantially parallel to each other in the left-right direction.

[0061] With a motor mount 70 having a structure according to this embodiment, the same effects as the motor mount 10 of the first embodiment can be obtained. As can be seen from this embodiment, the relative orientation of the motor-side vibration damping support part 12 and the body-side vibration damping support part 14 is not particularly limited and can be set as appropriate depending on the mounting structure and layout of the vehicle.

[0062] Figures 8 to 10 show a motor mount 80 for an automobile as a fourth embodiment of the vibration isolation device for electric motors according to the present invention. The motor mount 80 has a structure in which a motor-side vibration isolation support portion 82 and a body-side vibration isolation support portion 84 are mounted on a mass member 86.

[0063] The motor-side vibration-damping support section 82 has a structure in which a first inner shaft member 88 and a first outer cylindrical member 90 are connected by a first elastic body 92. The first outer cylindrical member 90 is a substantially cylindrical shape with a thinner wall and larger diameter than the first inner shaft member 88, and is fitted onto the first inner shaft member 88. A flange portion 94 that extends outward is integrally formed at one axial end of the first outer cylindrical member 90. The other axial end of the first outer cylindrical member 90 is bent inward.

[0064] The first elastic body 92 is substantially cylindrical in shape and is positioned radially between the first inner shaft member 88 and the first outer cylindrical member 90. Its inner circumferential surface is fixed to the outer circumferential surface of the first inner shaft member 88, and its outer circumferential surface is fixed to the inner circumferential surface of the first outer cylindrical member 90. Similar to the first elastic body 56 in the second embodiment, the first elastic body 92 has a pair of axially penetrating holes 58, 58 on both the upper and lower sides of the first inner shaft member 88, and a pair of rubber arms 60, 60 are formed between these pairs of axially penetrating holes 58, 58, extending substantially in the front-rear direction.

[0065] A right stopper rubber 96, which serves as an adjustment rubber integrally formed with the first elastic body 92, is fixed to the flange portion 94 of the first outer cylindrical member 90. The right stopper rubber 96 protrudes to the right from the flange portion 94 and narrows radially towards the protruding tip. Four right stopper rubbers 96, each with substantially the same shape, are arranged in a line in the circumferential direction. The central portion of the right stopper rubber 96 in the circumferential direction has a greater protruding height than the portions at both ends.

[0066] The right stopper rubber 96 abuts against the right stopper plate 98, which is superimposed on the right end of the first inner shaft member 88. The right stopper plate 98 is substantially annular in shape and is provided so as to widen outward on the right side of the first inner shaft member 88. The right stopper plate 98 is fixed to the first inner shaft member 88 by means of welding or other means, and forms a flange-like portion at the right end of the first inner shaft member 88.

[0067] In this structure, a right stopper rubber 96 is positioned between the axially opposing surfaces of a right stopper plate 98 fixed to the first inner shaft member 88 and the flange portion 94 of the first outer cylindrical member 90. As a result, when the first inner shaft member 88 is displaced relative to the first outer cylindrical member 90 in the axial direction to the right, the right stopper plate 98 and the flange portion 94 come into contact with each other via the right stopper rubber 96. This constitutes a right-side stopper mechanism that limits the amount of relative displacement between the first inner shaft member 88 and the first outer cylindrical member 90, and consequently, the amount of elastic deformation of the first elastic body 92.

[0068] The right stopper rubber 96 is pre-butted against the right stopper plate 98 in a stationary state and contributes to the spring of the motor-side vibration isolation support 82. By adjusting the amount of tightening (compression deformation in the left-right direction) of the right stopper rubber 96, the primary resonant frequency of the vibration system 42, which uses the motor-side vibration isolation support 82 as a spring, can be tuned. In this way, the right stopper rubber 96 functions as an adjustment rubber for adjusting the primary resonant frequency of the vibration system 42, and constitutes a tuning mechanism for adjusting the primary resonant frequency of the vibration system 42.

[0069] The body-side vibration isolation support section 84 has a structure in which the second inner shaft member 100 and the second outer cylindrical member 102 are connected by a second elastic body 104. The body-side vibration isolation support section 84 in this embodiment has a common structure with the motor-side vibration isolation support section 82, and the second inner shaft member 100 has the same shape and size as the first inner shaft member 88, the second outer cylindrical member 102 has the same shape and size as the first outer cylindrical member 90, and the second elastic body 104 has the same shape and size as the first elastic body 92, so a detailed explanation is omitted here. The second inner shaft member 100 is provided with a right stopper plate 98 that forms a flange-like portion at its right end in the axial direction, similar to the first inner shaft member 88.

[0070] The motor-side vibration damping support portion 82 and the body-side vibration damping support portion 84 are mounted on the mass member 86. The mass member 86 is a thick, roughly rectangular plate, with the plate thickness direction being the left-right direction and the vertical direction being longer than the front-rear direction. The mass member 86 has a first mounting hole 34 and a second mounting hole 36 that penetrate in the left-right direction and are formed side by side in the vertical direction. In this embodiment, the upper part of the mass member 86 where the first mounting hole 34 is formed is the first plate-like portion 106, and the lower part where the second mounting hole 36 is formed is the second plate-like portion 108, but the first plate-like portion 106 and the second plate-like portion 108 are provided continuously without being clearly separated by shape or the like.

[0071] Then, the first outer cylindrical member 90 is press-fitted and fixed into the first mounting hole 34 from the right side, and the motor-side vibration damping support part 82 is mounted in the first mounting hole 34. At the same time, the second outer cylindrical member 102 is press-fitted and fixed into the second mounting hole 36 from the right side, and the body-side vibration damping support part 84 is mounted in the second mounting hole 36. In this embodiment, the first mounting hole 34 and the second mounting hole 36 have a reduced diameter due to the left side of the opening periphery protruding inward in an inward flange shape, which prevents the first and second outer cylindrical members 90 and 102 from coming out to the left. In addition, the flange portions 94, 94 of the first and second outer cylindrical members 90 and 102 are superimposed in the left-right direction on the right side of the opening periphery of the first and second mounting holes 34 and 36, thereby positioning the first and second outer cylindrical members 90 and 102 with respect to the mass member 86 in the left-right direction.

[0072] A first stopper member 110 is attached to the left end of the first inner shaft member 88, which protrudes to the left from the first mounting hole 34. The first stopper member 110 has a left stopper plate 112 as a flange-like portion. The left stopper plate 112 is roughly annular in shape, similar to the right stopper plate 98, and is fixed to the first inner shaft member 88 by being fastened together with it when the first inner shaft member 88 is bolted to the electric motor 38, and protrudes outward at the axial end of the first inner shaft member 88.

[0073] On the outer circumference of the right side of the left stopper plate 112, a cylindrical fitting rubber 114 that fits onto the left end of the first inner shaft member 88 and a left stopper rubber 116 that acts as an adjustment rubber and protrudes toward the mass member 86 on the outer circumference side of the fitting rubber 114 are fixed. The fitting rubber 114 and the left stopper rubber 116 are provided integrally and are separate from the first elastic body 92. The left stopper rubber 116 is positioned between the axially opposing surfaces of the left stopper plate 112 and the mass member 86 (the opening peripheral edge of the first mounting hole 34), and has a tapered cross-sectional shape that narrows radially toward the protruding tip. Similar to the right stopper rubber 96, four left stopper rubbers 116 are provided arranged in a circumferential direction.

[0074] Furthermore, when the first inner shaft member 88 is displaced to the right relative to the first outer cylindrical member 90 and the mass member 86, the left stopper plate 112 and the mass member 86 come into contact with each other via the left stopper rubber 116 in a cushioning manner. This limits the relative displacement between the first inner shaft member 88 and the first outer cylindrical member 90 and the mass member 86, thereby limiting the amount of elastic deformation of the first elastic body 92 and improving the durability of the first elastic body 92.

[0075] The left stopper rubber 116 is pre-butted against the mass member 86 in a stationary state and contributes to the spring of the motor-side vibration isolation support 82. By adjusting the amount of tightening (compression deformation in the left-right direction) of the left stopper rubber 116, the primary resonant frequency of the vibration system 42, which uses the motor-side vibration isolation support 82 as a spring, can be tuned. In this way, the left stopper rubber 116 functions as an adjustment rubber for adjusting the primary resonant frequency of the vibration system 42, and constitutes a tuning mechanism for adjusting the primary resonant frequency of the vibration system 42.

[0076] A second stopper member 118 is attached to the second inner shaft member 100 of the body-side vibration-damping support section 84. The second stopper member 118 has the same shape and size as the first stopper member 110, and has a structure in which a fitting rubber 114 and a left stopper rubber 116 are fixed to the left stopper plate 112. The second stopper member 118, like the first stopper member 110, constitutes a stopper that limits the amount of displacement of the second inner shaft member 100 to the right relative to the second outer cylindrical member 102 and the mass member 86, thereby improving the durability of the second elastic body 104.

[0077] In the motor mount 80 with a structure according to this embodiment, stopper mechanisms are provided in the vertical and horizontal directions, where the spring characteristics of the first and second elastic bodies 92 and 104 become relatively softer due to the shear spring component of the rubber arms 60 and 60, respectively, thereby improving the durability of the first and second elastic bodies 92 and 104.

[0078] Furthermore, the motor mount 80 is configured to allow adjustment of the resonant frequency of the vibration system 42 while maintaining the spring characteristics of the first and second elastic bodies 92 and 104, through a tuning mechanism consisting of tightening of the left and right stopper rubbers 96 and 116. Therefore, while effectively obtaining the vibration damping effect of the first and second elastic bodies 92 and 104, the effect of suppressing vibration transmission by anti-resonance of the vibration system 42 can also be efficiently obtained.

[0079] Although embodiments of the present invention have been described in detail above, the present invention is not limited by its specific description. For example, the relative orientation of the thickness direction of the first plate-like portion and the thickness direction of the second plate-like portion is set appropriately according to the mounting direction to the electric motor and vehicle body, etc., and is not particularly limited.

[0080] Multiple vibration-damping support units may be provided on the motor side relative to the mass member. Similarly, multiple vibration-damping support units may be provided on the body side relative to the mass member.

[0081] 10 Motor mount (vibration isolation device for electric motor in the first embodiment) 12 Motor-side vibration isolation support part 14 Body-side vibration isolation support part 16 Mass member 18 First inner shaft member (inner shaft member) 20 First elastic body (elastic body) 22 Bolt hole 24 Groove 26 Second inner shaft member (inner shaft member) 28 Second elastic body (elastic body) 30 First plate-shaped part 32 Second plate-shaped part 34 First mounting hole 36 Second mounting hole 38 Electric motor 40 Vehicle body 42 Vibration system 50 Motor mount (vibration isolation device for electric motor in the second embodiment) 52 Motor-side vibration isolation support part 54 First outer cylindrical member 56 First elastic body 58 Cut hole 60 Rubber arm 62 Stopper rubber 70 Motor mount (vibration isolation device for electric motor in the third embodiment) 72 Mass member 74 80 Second plate-shaped part Motor mount (vibration isolation device for electric motor in the fourth embodiment) 82 Motor-side vibration isolation support part 84 Body-side vibration isolation support part 86 Mass member 88 First inner shaft member 90 First outer cylindrical member 92 First elastic body 94 Flange part 96 Right stopper rubber (adjustment rubber) 98 Right stopper plate (flange-shaped part) 100 Second inner shaft member 102 Second outer cylindrical member 104 Second elastic body 106 First plate-shaped part 108 Second plate-shaped part 110 First stopper member 112 Left stopper plate (flange-shaped part) 114 Fitting rubber 116 Left stopper rubber (adjustment rubber) 118 Second stopper member

Claims

1. A vibration isolation device for an electric motor that vibrationally connects an electric motor and a vehicle body, wherein a motor-side vibration isolation support attached to the electric motor side and a body-side vibration isolation support attached to the vehicle body side are provided on a mass member, and the primary resonant frequency of the vibration system formed by the mass member elastically supported by the motor-side vibration isolation support and the body-side vibration isolation support is tuned to a lower frequency than the frequency of the vibration to be isolated caused by the electric motor.

2. The vibration isolation device for an electric motor according to claim 1, wherein the ratio of the static support load of the mass member exerted on the motor-side vibration isolation support portion to the static support load of the mass member exerted on the body-side vibration isolation support portion is within the range of 80% to 120%.

3. The vibration isolation device for an electric motor according to claim 1 or 2, wherein the motor-side vibration isolation support portion and the body-side vibration isolation support portion each have a structure in which an inner shaft member is inserted into a mounting hole formed in the mass member, an elastic body is disposed between the outer circumferential surface of the inner shaft member and the inner surface of the mounting hole, and the inner shaft member and the mass member are mutually connected by the elastic body.

4. A vibration damping device for an electric motor according to claim 3, wherein a flange-like portion is provided at the axial end of the inner shaft member that protrudes outward, an adjustment rubber is disposed between the axially opposing surfaces of the opening periphery of the mounting hole in the mass member and the flange-like portion, and a tuning mechanism is provided to adjust the primary resonant frequency of the vibration system by tightening the adjustment rubber between the mass member and the flange-like portion.

5. The vibration damping device for an electric motor according to claim 3 or 4, wherein the mounting hole provided with the motor-side vibration damping support portion and the mounting hole provided with the body-side vibration damping support portion extend parallel to each other.

6. The vibration damping device for an electric motor according to claim 3 or 4, wherein the mass member comprises a first plate-like portion in which the mounting hole for which the motor-side vibration damping support portion is provided penetrates in the plate thickness direction, and a second plate-like portion in which the mounting hole for which the body-side vibration damping support portion is provided is provided, and the plate thickness direction of the first plate-like portion and the plate thickness direction of the second plate-like portion are in different directions from each other.

7. The vibration isolation device for an electric motor according to any one of claims 1 to 6, wherein one motor-side vibration isolation support and one body-side vibration isolation support are provided.

8. The vibration isolation device for an electric motor according to claim 7, wherein the center of gravity of the mass member, the elastic center of the motor-side vibration isolation support, and the elastic center of the body-side vibration isolation support are located on the same straight line.

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