阅读说明：本技术 电动汽车用防振装置的配设结构 (Arrangement structure of vibration isolator for electric vehicle ) 是由 冈村健 于 2018-12-21 设计创作，主要内容包括：技术问题：提供一种能够在规定范围以上的载荷作用于电动汽车用防振装置的情况下,抑制电动汽车用防振装置的动态弹簧常数急剧增高的电动汽车用防振装置的配设结构。解决手段：关于电动汽车用防振装置(100),在与安装于汽车的车身的状态下的内筒部件(10)在重力方向上重叠的位置的防振基体(30),未形成沿着内筒部件(10)的轴向贯通的贯通孔,在到防振基体的自由长度的30％为止的挠曲量的范围内,重力方向的载荷相对于防振基体(30)的挠曲量的特性具有线性,因此能够在规定范围内的载荷在重力方向上作用于电动汽车用防振装置(100)的情况下,抑制动态弹簧常数急剧增高。(The technical problem is as follows: provided is an arrangement structure of an electric vehicle vibration isolator, which can suppress a rapid increase in the dynamic spring constant of the electric vehicle vibration isolator when a load in a predetermined range or more acts on the electric vehicle vibration isolator. The solution is as follows: in the anti-vibration device (100) for an electric vehicle, a through hole penetrating along the axial direction of an inner tube member (10) is not formed in an anti-vibration base (30) at a position overlapping the inner tube member (10) in the gravity direction in a state of being mounted on the vehicle body of the vehicle, and the characteristic of a load in the gravity direction with respect to the deflection amount of the anti-vibration base (30) is linear in a deflection amount range up to 30% of the free length of the anti-vibration base, so that the dynamic spring constant can be prevented from increasing sharply when the load in a predetermined range acts on the anti-vibration device (100) for the electric vehicle in the gravity direction.)

1. A structure for disposing a vibration isolator for electric vehicle, comprising a vibration isolator for electric vehicle and a vehicle body of an electric vehicle on which the vibration isolator for electric vehicle is disposed, the vibration isolator for electric vehicle comprising a cylindrical inner tube member, an outer tube member formed in a cylindrical shape surrounding the outer side of the inner tube member and disposed coaxially with the axis of the inner tube member, and a vibration isolation base body made of a rubber-like elastic material and connecting the outer circumferential surface of the inner tube member and the inner circumferential surface of the outer tube member, the structure for disposing a vibration isolator for electric vehicle being characterized in that the vibration isolator for electric vehicle is disposed on the vehicle body,

the vibration isolator for an electric vehicle is disposed on the vehicle body in a state in which the axes of the inner tube member and the outer tube member are oriented in the horizontal direction,

the vibration isolation base has no through hole formed at a position overlapping the inner tube member in the direction of gravity, and has a free length in the radial direction set to be 0.5 times or more and 1.0 times or less of the axial length of the side connected to the inner tube member, and the cross-sectional area of the cut surface when the vibration isolation base is continuously cut along the axial direction at each position in the radial direction is set to be constant at each position in the radial direction, and the characteristic of the load in the direction of gravity with respect to the amount of deflection of the vibration isolation base is linear within a range of the amount of deflection up to 30% of the free length of the vibration isolation base.

Technical Field

The present invention relates to an arrangement structure of a vibration isolator for an electric vehicle, and more particularly, to an arrangement structure of a vibration isolator for an electric vehicle, which can suppress a rapid increase in a dynamic spring constant of the vibration isolator for an electric vehicle when a load in a predetermined range or more acts on the vibration isolator for an electric vehicle.

Background

A conventional vibration damping device for supporting a drive source of an automobile on a vehicle body includes: the vibration isolator is composed of an inner cylinder member formed in a cylindrical shape, an outer cylinder member formed in a cylindrical shape surrounding the outer side of the inner cylinder member, and a vibration isolation base body formed of an elastic body such as rubber and connecting the inner cylinder member and the outer cylinder member.

According to such a vibration isolation device, in general, in a state where the vibration isolation device is mounted on a vehicle body of an automobile, a through hole penetrating along an axial direction of an inner tube member is formed in a vibration isolation base body at a position overlapping with the inner tube member in a gravity direction, and when a load in a predetermined range is applied in the gravity direction, a dynamic spring constant is suppressed from increasing to a predetermined value or more (patent document 1).

Disclosure of Invention

Technical problem to be solved

However, the conventional vibration isolator having the through hole has the following problems: when the load in the gravity direction is within a predetermined range or more, the vibration-proof base deforms and the space inside the through-hole collapses (the inner surfaces of the through-hole abut against each other), and the dynamic spring constant rapidly increases.

Further, in a gasoline engine, a diesel engine, and the like as a driving source of an engine-type automobile, there are a downward inclination: the sound to be driven at the high-speed rotation is likely to be larger than that at the low-speed rotation. Therefore, in the engine-type automobile, the abnormal noise generated by the increase in the dynamic spring constant of the vibration isolator is masked by the sound of the driving engine at the time of high-speed rotation. However, the electric motor as a driving source of the electric vehicle is driven at a higher speed with less sound than the engine. Therefore, in the electric vehicle, abnormal noise generated by an increase in the dynamic spring constant of the vibration isolator is likely to affect the vehicle interior when the vehicle is rotated at a high speed. Therefore, in the electric vehicle, it is necessary to reduce the dynamic spring constant when the drive source is rotated at high speed.

Further, the torque value of the electric motor as a driving source of the electric vehicle is larger when driving than when driving the engine. Therefore, in the electric vehicle, a larger load is likely to act on the inner tube member than in the engine type vehicle. Therefore, in the electric vehicle, the dynamic spring constant of the vibration isolator is likely to be higher than that of the engine type vehicle.

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an arrangement structure of an electric vehicle vibration isolator capable of suppressing a rapid increase in dynamic spring constant of the electric vehicle vibration isolator when a load in a predetermined range or more acts on the electric vehicle vibration isolator in the arrangement structure of the electric vehicle vibration isolator.

(II) technical scheme

In order to achieve the object, the present invention provides a structure for disposing a vibration isolator for electric vehicle, comprising a cylindrical inner tube member, an outer tube member formed in a cylindrical shape surrounding an outer side of the inner tube member and disposed coaxially with an axis of the inner tube member, and a vibration isolation base body made of a rubber-like elastic material and connecting an outer circumferential surface of the inner tube member and an inner circumferential surface of the outer tube member, wherein the vibration isolator for electric vehicle is disposed on a vehicle body in a state where axes of the inner tube member and the outer tube member are oriented in a horizontal direction, and wherein a through hole is not formed at a position where the vibration isolation base body overlaps the inner tube member in a gravity direction, and the free length in the radial direction is set to be 0.5 times or more and 1.0 times or less of the axial length of the side connected to the inner tube member, the cross-sectional area of the cut surface when the sheet is continuously cut at each position in the radial direction along the axial direction is set to be constant at each position in the radial direction, and the characteristic of the load in the gravity direction with respect to the amount of deflection of the vibration-proof base is linear in the range of the amount of deflection up to 30% of the free length of the vibration-proof base.

(III) advantageous effects

According to the arrangement structure of the vibration isolator for electric vehicle of the first aspect, since the vibration isolator for electric vehicle is arranged on the vehicle body in a state where the axes of the inner tube member and the outer tube member are oriented in the horizontal direction, and the free length of the vibration isolation base body in the radial direction is set to be 0.5 times or more of the axial length of the vibration isolation base body on the side connected to the inner tube member, the sectional area of the cut surface of the vibration-proof base body when the vibration-proof base body is continuously cut at each position in the radial direction along the axial direction is set to be constant at each position in the radial direction, the characteristic of the load in the gravity direction with respect to the deflection amount of the vibration-proof base body has linearity in the range of the deflection amount up to 30% of the free length of the vibration-proof base body, therefore, when a load within a predetermined range acts on the vibration isolator for electric vehicles in the direction of gravity, the dynamic spring constant of the vibration isolator for an electric vehicle is prevented from increasing to a predetermined value or more.

Further, since no through-hole is formed in the position where the vibration isolation base overlaps the inner tube member in the gravity direction, the inner surfaces do not abut against each other as in the conventional vibration isolation device in which a through-hole is formed. As a result, when a load in a predetermined range or more acts on the electric vehicle vibration isolator in the direction of gravity, a rapid increase in the dynamic spring constant of the electric vehicle vibration isolator can be suppressed.

In the vibration isolator for electric vehicles, the free length of the vibration isolation base in the radial direction is set to be 1.0 times or less the axial length of the vibration isolation base connected to the inner tube member, and therefore, the dynamic spring constant in the axial direction of the vibration isolator for electric vehicles can be suppressed from becoming excessively small, and the required characteristics of the vehicle can be satisfied.

Drawings

In fig. 1, (a) is a side view of the anti-vibration device for an electric vehicle according to the first embodiment of the present invention, and (b) is a sectional view of the anti-vibration device for an electric vehicle taken along line Ib-Ib in fig. 1 (a).

In fig. 2, (a) is a graph showing characteristics of a load applied to the anti-vibration device for an electric vehicle with respect to an amount of deflection of the anti-vibration base, and (b) is a graph showing a relationship between a dynamic spring constant and a frequency of the anti-vibration device for an electric vehicle according to the first to third embodiments.

Fig. 3 shows a side view of the vibration isolator for electric vehicles according to the second embodiment, and a cross-sectional view of the vibration isolator for electric vehicles taken along line IIIb-IIIb in fig. 3 (a).

Fig. 4 shows a side view of the vibration isolator for electric vehicles according to the third embodiment (a) and a cross-sectional view of the vibration isolator for electric vehicles taken along line IVb-IVb in fig. 4 (a).

Fig. 5 is a front view of a portion of the vibration isolator for electric vehicle and the mounting bracket according to the fourth embodiment, and (b) is an exploded perspective front view of the vibration isolator for electric vehicle.

In fig. 6, (a) is a sectional view of the anti-vibration device for electric vehicles taken along line VIa-VIa in fig. 5 (a), and (b) is a sectional view of the anti-vibration device for electric vehicles taken along line VIb-VIb in fig. 6 (a).

Fig. 7 shows a sectional view of the vibration isolator for electric vehicles according to the fifth embodiment (a) and a sectional view of the vibration isolator for electric vehicles along line VIIb-VIIb in fig. 7 (a).

Fig. 8 shows a side view of the anti-vibration device for an electric vehicle according to the sixth embodiment in (a) and a side view of the anti-vibration device for an electric vehicle according to the seventh embodiment in (b).

Detailed Description

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. Fig. 1 (a) is a side view of an antivibration device for electric vehicles 100 according to a first embodiment of the present invention, and fig. 1 (b) is a sectional view of the antivibration device for electric vehicles 100 taken along line Ib-Ib in fig. 1 (a). Fig. 2 (a) is a diagram showing the characteristics of the load (N) applied to the anti-vibration device for electric vehicle 100 with respect to the amount of deflection (mm) of the anti-vibration base 30, and fig. 2 (b) is a diagram showing the relationship of the dynamic spring constant (N/mm) with respect to the frequency (Hz) of the anti-vibration devices for electric vehicle 100, 200, 300 of the first to third embodiments.

In the following description, with respect to the electric vehicle vibration damping device 100 shown in fig. 1 (a), the left side of the drawing sheet is the front (front) side of the vehicle body in a state where the electric vehicle vibration damping device 100 is disposed on the vehicle body, the right side of the drawing sheet is the rear (back) side of the vehicle body in a state where the electric vehicle vibration damping device 100 is disposed on the vehicle body, the back side of the drawing sheet is the right side of the vehicle body in a state where the electric vehicle vibration damping device 100 is disposed on the vehicle body, the near side of the drawing sheet is the left side of the vehicle body in a state where the electric vehicle vibration damping device 100 is disposed on the vehicle body, the upper side of the drawing sheet is the upper side of the vehicle body in a state where the electric vehicle vibration damping device 100 is disposed on the vehicle body, and the lower side of the drawing sheet is the lower side of the vehicle body in a state where the electric vehicle vibration damping device 100 is disposed on the vehicle body, arrows F-B, U-D and L-R respectively indicate the front-back.

Fig. 2 (a) is a diagram showing characteristics of a load (N) acting in the direction of gravity with respect to a deflection amount (mm) of the vibration isolation base 30 in a state where the vibration isolation device 100 for an electric vehicle is mounted on the vehicle body of the vehicle. In fig. 2 (a), the horizontal axis indicates a state in which the amount of deflection of the vibration-proof base 30 in the negative direction is increased as the amount of deflection is increased to the left with respect to 0mm, the positive direction is increased as the amount of deflection is increased to the right with respect to 0mm, and the vertical axis indicates a state in which the load is applied to the lower side in the gravity direction as the upper side with respect to 0N, which is a load acting in the gravity direction, is increased as the lower side is increased, and the upper side in the gravity direction is increased as the lower side is increased with respect to 0N, which is a load acting in the gravity direction.

In fig. 2a, points on the line of the drawing are shown at position reference points P1 and P2, where the line is switched from a straight line shape (having a linear region) to a curved line shape, symbols at positions of the points P1 and P2, where the deflection amount (mm) of the vibration-proof base 30 is indicated by a number a1 and a2, symbols at positions of the deflection amount (mm) in a range of ± 30% with respect to the free length (mm) of the vibration-proof base 30, where B1 and B2 are indicated, and a symbol at which the minimum value of the load in a predetermined range of the electric automobile vibration-proof device 100, which will be described later, is indicated by a number N1 and the maximum value thereof is indicated by a number N2.

In fig. 2 (b), the dynamic spring constant (N/mm) with respect to the frequency (Hz) of the electric automobile vibration isolator 100 of the first embodiment is indicated by a solid line, the dynamic spring constant (N/mm) with respect to the frequency (Hz) of the electric automobile vibration isolator 200 of the second embodiment is indicated by a broken line, and the dynamic spring constant (N/mm) with respect to the frequency (Hz) of the electric automobile vibration isolator 300 of the third embodiment is indicated by a two-dot chain line.

In fig. 2 (b), the horizontal axis represents the vibration frequency of the input vibration isolation base 30, 230, 330, and represents the state in which the input value increases as the vibration frequency moves to the right, and the vertical axis represents the dynamic spring constant of the electric automobile vibration isolation device 100, 200, 300, and the dynamic spring constant increases as the vibration frequency moves to the upper side. In fig. 2 (b), a position at which the vibration frequency when the drive source is driven is denoted by C1, a position at which the dynamic spring constant of the line X is the maximum vibration frequency is denoted by C3, a position at which the dynamic spring constant of the line X is the upper limit of the range of the predetermined vibration frequency from C1 is denoted by C2, a position at which the dynamic spring constant of the line Y is the maximum vibration frequency is denoted by C4, and a position at which the predetermined value of the dynamic spring constant described later is denoted by K1.

The predetermined range of vibration frequency is a vibration frequency generated by driving a driving source such as a motor, and is applied in a range from C1 to C2 in fig. 2 (b).

As shown in fig. 1, the vibration isolator 100 for an electric vehicle is a bush provided between a drive source such as a motor and a vehicle body. The vibration isolation device 100 for an electric vehicle includes: the vibration-proof device includes a cylindrical inner tube member 10 formed of a metal material such as iron or aluminum and having an axis O, a cylindrical outer tube member 20 disposed concentrically with the inner tube member 10 and formed of a metal material such as iron or aluminum, and a vibration-proof base 30 formed of a rubber-like elastic material and connecting an outer circumferential surface of the inner tube member 10 and an inner circumferential surface of the outer tube member 20.

The anti-vibration device 100 for an electric vehicle is manufactured by vulcanization-bonding the anti-vibration base 30 between the inner tubular member 10 and the outer tubular member 20, and then reducing the diameter of the outer tubular member 20. Fig. 1 shows an electric vehicle vibration isolator 100 in which an outer tubular member 20 is reduced in diameter.

The inner tube member 10 is a member coupled to a drive side bracket coupled to a drive source of an electric vehicle such as an electric motor. The inner tube member 10 is fastened to the driving bracket by a bolt inserted into the inside of the tube, and is connected to the driving bracket.

The outer tube member 20 is a member fitted into a bracket on the vehicle body side connected to the vehicle body of the automobile. The outer tube member 20 is press-fitted to the inside of a bracket on the vehicle side, which is formed in an annular shape having an inner diameter substantially equal to the outer diameter of the outer tube member 20, and is connected to the bracket on the vehicle side.

The vibration-proof base 30 includes: the elastic deformation portion 33 is formed by a first film portion 31 covering the outer peripheral surface of the inner tube member 10 with a constant thickness, a second film portion 32 covering the inner peripheral surface of the outer tube member 20 with a constant thickness, and an elastic deformation portion 33 connecting the first film portion 31 and the second film portion 32, and the first film portion 31, the second film portion 32, and the elastic deformation portion 33 are formed in an annular shape continuously formed in one circumferential direction around the axis O.

The first film portion 31 and the second film portion 32 are protection portions that prevent the inner tube member 10 and the outer tube member 20 from directly contacting each other. The first film portion 31 and the second film portion 32 can suppress damage to the vibration isolator 100 for an electric vehicle due to contact between the inner tube member 10 and the outer tube member 20 when the inner tube member 10 is excessively displaced with respect to the outer tube member 20 due to rapid acceleration or rapid stop of the vehicle.

The elastically deformable portion 33 is formed to have a substantially trapezoidal cross section when cut along the axis O direction (the direction of arrow L-R) by a plane passing through the axis O (see fig. 1 b), and the thickness of the elastically deformable portion 33 in the axis O direction decreases from the inner cylindrical member 10 (the first film portion 31) to the outer cylindrical member 20 (the second film portion 32) (radially outward from the axis O).

Specifically, if the distance from the elastically deforming part 33 in the radial direction from the axis O is taken as R and the thickness of the elastically deforming part 33 in the direction along the axis O at the position of R is taken as H, 2 pi × R × H is taken as constant, and thus, the elastically deforming part 33 is set in an arc shape in which both end surfaces in the axis O direction are recessed inward in the axis O direction.

In the elastically deformable portion 33, a reinforcing portion 33a is formed at a corner portion of a connecting portion connecting the first film portion 31 and the second film portion 32. The reinforcing portion 33a is a portion for reinforcing the connecting portion between the first film portion 31 and the second film portion 32 and the elastic deformation portion 33, and is formed to have a slight thickness.

The reinforcing portion 33a protrudes from the elastically deforming portion 33 by about 5% at maximum in the direction along the axis O (the direction of the arrow L-R), and therefore, when the distance from the elastically deforming portion 33 in the radial direction from the axis O is taken as R and the thickness of the elastically deforming portion 33 in the direction along the axis O at the position of R is taken as H, the sectional area of the cut surface of the elastically deforming portion 33 at each position in the radial direction is constant within the range of 5%.

As shown in fig. 2a, a free length R2 in the radial direction of the vibration isolation base 30 about the axis O (the distance from the outer peripheral surface of the inner tube member 10 to the inner peripheral surface of the outer tube member 20 (see fig. 1B)) is set such that, when a load (N) in the direction of gravity (the direction of arrow U-D) acts on the vibration isolation device 100 for an electric vehicle in a state where the vibration isolation device 100 for an electric vehicle is mounted on the vehicle body of the vehicle, the load in the direction of gravity has a linear characteristic with respect to the deflection amount (mm) of the vibration isolation base 30 in a range up to ± 30% of the deflection amount (mm) of the free length R2 of the vibration isolation base 30 (the range from B1 to B2 in fig. 2 a). That is, both ends a1 and a2 of the straight line portion shown in fig. 2 (a) are positioned outside B1 and B2 (a1 < B1 < B2 < a 2). Thus, the anti-vibration device for electric vehicle 100 can suppress the dynamic spring constant of the anti-vibration device for electric vehicle 100 from increasing to a predetermined value (K1 in fig. 2 b) or more when a load in a predetermined range (range of N1 to N2 in fig. 2 a) acts in the direction of gravity.

The load in the predetermined range (the range from N1 to N2 in fig. 2 a) is a load that normally acts in the range of the anti-vibration device for an electric vehicle 100 when the vehicle is accelerated or stopped suddenly. In the present embodiment, the range is set to a range of ± 4000N, which is a narrower range than the load range of the positions corresponding to the point P1 and the point P2. That is, in the present embodiment, the load in the predetermined range (the range of N1 to N2 in fig. 2 a) is set to a region in which the load in the gravity direction has a linear characteristic with respect to the deflection amount of the vibration isolation base 30.

The predetermined value of the dynamic spring constant (K1 in fig. 2 b) is the maximum value of a value that can absorb vibration caused by driving a drive source of an automobile and suppress transmission of the vibration to a vehicle body, and is set to 5000N/mm in the present embodiment. The anti-vibration device 100 for an electric vehicle can suppress transmission of vibration to the vehicle body caused by driving of the drive source of the vehicle and resonance of a member arranged in the vehicle body due to the vibration by setting the dynamic spring constant to a predetermined value or less.

Further, the free length R2 of the vibration isolation base 30 can be appropriately changed depending on the thickness of the elastic deformation portion 33 in the axis O direction (the direction of arrow L-R) and the material (elastic modulus) of the vibration isolation base 30, and is set to a value such that, when a load acts on the electric automobile vibration isolation device 100, the characteristic of the load in the gravity direction with respect to the amount of deflection of the vibration isolation base 30 has linearity (linear shape) within the range of the amount of deflection in the region of ± 30% of the free length R2 of the vibration isolation base 30, in this case, the free length R2 is preferably set to be 0.5 times or more and 1.0 times or less with respect to the axial length H2 (see fig. 1 (b)) of the elastic deformation portion 33 on the first film portion 31 (inner tube member 10) side, in order to suppress the dynamic spring constant of the electric automobile vibration isolation device 100 from becoming a predetermined value or more and suppress deterioration in durability of the electric automobile vibration isolation device 100 when a load in a predetermined range acts on the electric automobile device 100.

Specifically, in the anti-vibration device for electric vehicle 100, when a load in the gravitational direction (the direction of arrow U-D) in a predetermined range acts on the anti-vibration device for electric vehicle 100 by increasing the value of the free length R2 (the thickness in the radial direction about the axis O) of the anti-vibration base 30, the characteristic of increasing the load in the gravitational direction with respect to the amount of deflection of the anti-vibration base 30 can have a linear range (the range of points P1 to P2 in fig. 2 a). However, if the free length R2 is too large, the dynamic spring constant in the axial O direction of the anti-vibration device 100 for an electric vehicle decreases in accordance with the degree of increase in the radial direction of the anti-vibration base 30, and the required characteristics of the vehicle cannot be satisfied.

In the anti-vibration device for an electric vehicle 100, the free length R2 is set to be 1.0 times or less the axial length H2 (see fig. 1 (b)) of the elastically deformable portion 33 on the first film portion 31 side, whereby the dynamic spring constant in the axial O direction of the anti-vibration device for an electric vehicle 100 can be suppressed from becoming too small, and the required characteristics of the vehicle can be satisfied.

On the other hand, in the anti-vibration device 100 for an electric vehicle, the free length R2 of the anti-vibration base 30 (the thickness in the radial direction around the axis O) is reduced, whereby the thickness of the anti-vibration base 30 on the outer side in the radial direction can be increased, and the durability of the anti-vibration device 100 for an electric vehicle can be easily improved. However, when the free length R2 is too small, a range in which the characteristic of the load in the gravity direction with respect to the amount of deflection of the vibration-proof base 30 has linearity (a range of points P1 to P2 in fig. 2 (a)) is narrowed. Therefore, the anti-vibration device 100 for an electric vehicle cannot suppress the dynamic spring constant to a predetermined value or less when a load in the direction of gravity (the direction of arrow U-D) in a predetermined range acts.

In the anti-vibration device 100 for an electric vehicle, by setting the free length R2 to be 0.5 times or more the axial length H2 (see fig. 1 (b)) of the elastically deformable portion 33 on the first film portion 31 side, the characteristic of the load in the gravity direction with respect to the amount of deflection of the anti-vibration base 30 can be easily made linear within the range of ± 30% of the amount of deflection of the anti-vibration base 30 with respect to the free length R2 of the anti-vibration base 30. As a result, the anti-vibration device 100 for an electric vehicle can suppress the dynamic spring constant from becoming equal to or greater than the predetermined value when a load in a predetermined range acts in the direction of gravity.

Here, conventionally, there is a vibration damping device which is disposed between a vehicle body and a drive source and suppresses transmission of vibration of the drive source to the vehicle body. The conventional vibration isolator mainly includes: the vibration isolation device is characterized in that the vibration isolation device comprises an inner tube member formed in a cylindrical shape, an outer tube member arranged concentrically with the inner tube member, and a vibration isolation base body connecting the inner tube member and the outer tube member, wherein a through hole penetrating along the axial direction of the inner tube member is formed in the vibration isolation base body at a position overlapping the inner tube member in the gravity direction in a state where the vibration isolation device is arranged on a vehicle body of an automobile, and the dynamic spring constant can be suppressed from becoming equal to or more than a predetermined value in a case where a load in the gravity direction in a predetermined range acts on the.

However, the vibration isolation device in which the vibration isolation base body at the position overlapping the inner tube member in the gravity direction is formed with the through hole penetrating along the axial direction of the inner tube member has the following problems: when the vibration isolation base is deformed and the space inside the through hole collapses (the inner surfaces of the through hole abut against each other) due to a load of a predetermined range or more acting in the direction of gravity of the vibration isolation device, the dynamic spring constant rapidly increases.

Further, in a gasoline engine, a diesel engine, and the like as a driving source of an engine-type automobile, there are a downward inclination: the sound to be driven at the high-speed rotation is likely to be larger than that at the low-speed rotation. Therefore, in the engine-type automobile, the abnormal noise generated by the increase in the dynamic spring constant of the vibration isolator is masked by the sound of the driving engine at the time of high-speed rotation. However, the electric motor as a driving source of the electric vehicle is driven at a higher speed with less sound than the engine. Therefore, in the electric vehicle, abnormal noise generated by an increase in the dynamic spring constant of the vibration isolator is likely to affect the vehicle interior when the vehicle is rotated at a high speed. Therefore, in the electric vehicle, it is necessary to reduce the dynamic spring constant when the drive source is rotated at high speed.

Further, the torque value of the electric motor as a driving source of the electric vehicle is larger when driving than when driving the engine. Therefore, in the electric vehicle, a larger load is likely to act on the inner tube member than in the engine type vehicle. Therefore, in the electric vehicle, the dynamic spring constant of the vibration isolator is likely to be higher than that of the engine type vehicle.

In contrast to the conventional anti-vibration device described above, in the anti-vibration device 100 for an electric vehicle according to the present embodiment, in a state in which the anti-vibration device 100 for an electric vehicle is disposed in the vehicle body of the vehicle, no through hole is formed to the axis O direction (the direction of arrow L-R) at a position overlapping the inner tube member 10 in the gravity direction (the direction of arrow U-D).

Further, in the anti-vibration device for electric vehicle 100, since the through hole leading to the axis O direction (the arrow L-R direction) is not formed at the position overlapping the inner tube member 10 in the gravity direction (the arrow U-D direction), there is a risk that the dynamic spring constant against the vibration of the drive source increases when a load in a predetermined range acts in the gravity direction, whereas in the anti-vibration device for electric vehicle 100, the dynamic spring constant can be suppressed from increasing to a predetermined value or more when a load in the predetermined range acts on the anti-vibration device for electric vehicle 100 in the gravity direction because the characteristic of the load in the gravity direction against the deflection amount of the anti-vibration base 30 is linear within the range of the deflection amount of the anti-vibration base 30 of ± 30% of the free length R2 of the anti-vibration base 30.

Further, the sectional area of the cut surface of the vibration isolation base 30 when the elastic deformation portion 33 is continuously cut in the circumferential direction along the axis O direction (the direction of the arrow L-R) at each position in the radial direction around the axis O is set to a constant size at each position in the radial direction, whereby the vibration isolation device 100 for an electric vehicle can easily make the characteristic of the load in the gravity direction with respect to the amount of deflection of the vibration isolation base 30 linear within the range of the amount of deflection of the vibration isolation base 30 of ± 30% of the free length R2 of the vibration isolation base 30.

In the vibration isolator 100 for an electric vehicle according to the present embodiment, the outer diameter of the inner tube member 10 is set to 25mm, the inner diameter of the outer tube member 20 is set to 86mm, the free length of the vibration isolation base 30 is set to 30.5mm, and the thickness in the axis O direction of the first film portion 31 side (inner tube member 10 side) in the axis O direction (arrow L-R direction) is set to 50 mm.

Next, referring to fig. 3, a description will be given of an electric vehicle vibration isolator 200 of a second embodiment, in the first embodiment, a description has been given of a case where through holes (circular ring shape continuous in one circumferential direction) are not formed on both outer sides in the horizontal direction of the inner tube member 10 in a state where the electric vehicle vibration isolator 100 is disposed in the vehicle body of the vehicle, but in the electric vehicle vibration isolator 200 of the second embodiment, a recessed portion 233b penetrating in the axis O direction is formed on the outer side of the inner tube member 10 in the horizontal direction (horizontal direction of the inner tube member 10) orthogonal to the axis O direction (direction of arrow L-R).

Fig. 3 (a) is a side view of the anti-vibration device 200 for an electric vehicle according to the second embodiment, and fig. 3 (b) is a cross-sectional view of the anti-vibration device 200 for an electric vehicle taken along line IIIb-IIIb in fig. 3 (a).

As shown in fig. 3, the vibration isolator 200 for an electric vehicle according to the second embodiment is a bush provided between a drive source such as a motor and a vehicle body. The vibration isolation device 200 for an electric vehicle includes: the vibration isolation member includes a cylindrical inner tube member 10 formed of a metal material such as iron or aluminum and having an axis O, a cylindrical outer tube member 20 disposed concentrically with the inner tube member 10 and formed of a metal material such as iron or aluminum, and a vibration isolation base 230 formed of a rubber-like elastic material and connecting an outer circumferential surface of the inner tube member 10 and an inner circumferential surface of the outer tube member 20.

The anti-vibration device 200 for an electric vehicle is manufactured by vulcanization-bonding the anti-vibration base 230 between the inner tubular member 10 and the outer tubular member 20, and then reducing the diameter of the outer tubular member 20. Fig. 3 shows an electric vehicle vibration isolator 200 in which the outer tubular member 20 is reduced in diameter.

Vibration isolation base 230 includes: a first film portion 31 covering the outer peripheral surface of the inner tube member 10 with a constant thickness, a second film portion 32 covering the inner peripheral surface of the outer tube member 20 with a constant thickness, and an elastic deformation portion 233 connecting the first film portion 31 and the second film portion 32.

The elastically deformable portion 233 includes a reinforcing portion 33a formed at a corner portion of a connecting portion to the first film portion 31 and the second film portion 32, a recessed portion 233b formed to penetrate along the axis O direction outside (horizontal direction of the inner tube member 10) of the inner tube member 10 in the horizontal direction orthogonal to the axis O direction (direction of arrow L-R) in a state where the electric vehicle vibration isolator 200 is mounted on the vehicle body of the vehicle, and an upper side elastic portion 233c on the upper side and a lower side elastic portion 233D on the lower side separated by the pair of recessed portions 233b in the gravity direction (direction of arrow U-D).

Indentation 233b is a portion that reduces the weight of vibration isolation base 230. The recessed portion 233b is formed at a position where a part overlaps a horizontal region of the inner tube member 10 in a state where the vibration damping device 200 for an electric vehicle is mounted on the vehicle body of the vehicle, and is formed in a curved shape centering on the axis O of the inner tube member 10.

The depressed portion 233b is formed at a position at least partially overlapping with the horizontal region of the inner tube member 10. Accordingly, the volume of the vibration isolation base 230 located on both sides of the inner tube member 10 in the direction of gravity (the direction of arrow U-D) can be secured, compared to the case where the through-holes of the vibration isolation base 230 having the same size in the axial O direction are formed at positions that do not overlap the horizontal region of the inner tube member 10. As a result, in the anti-vibration device 200 for an electric vehicle, the amount of deformation of the anti-vibration base 230 when the anti-vibration base 230 elastically deforms in the direction of gravity can be reduced, and the durability of the anti-vibration device 200 for an electric vehicle can be ensured.

Further, the notch 233b is formed to pass through from the first film portion 31 to the second film portion 32 in the view angle of the axis O direction. Thus, the vibration isolation base 230 can deform the upper elastic portion 233c on the upper side (arrow U direction side) and the lower elastic portion 233D on the lower side (arrow D direction side) of the elastic deformation portions 233 as separate members.

Here, in the antivibration device for electric vehicle 100 described in the first embodiment, since the through-hole is not formed, the entire antivibration base 30 is heavy. Therefore, in the anti-vibration device 100 for an electric vehicle, there is a risk that: the natural frequency of the vibration isolation base 30 enters a predetermined range (range of C1 to C2 in fig. 2 b) of the vibration frequency input to the vibration isolation base 30 by driving the drive source, and the vibration isolation base 30 resonates to increase the dynamic spring constant of the vibration isolation device 100 for the electric vehicle to a predetermined value (K1 in fig. 2 b) or more.

In contrast, in the second embodiment, in a state where the vibration isolation device 200 for an electric vehicle is disposed in the vehicle body of the vehicle, the recessed portion 233b penetrating in the axis O direction is formed on the outer side of the inner tube member 10 (in the horizontal direction of the inner tube member 10) in the horizontal direction orthogonal to the axis O direction (the direction of the arrow L-R), and as a result, in the vibration isolation device 200 for an electric vehicle, the vibration isolation base 230 can be made light without affecting the deformability of the vibration isolation base 230 with respect to the load in the gravity direction (the direction of the arrow U-D) (ensuring the volume of the vibration isolation base 230 overlapping the inner tube member 10 in the gravity direction).

Further, the natural frequency F of the vibration isolation base 230 is obtained by F1/2 × (a), and (a) in the formula of the natural frequency F is a square root of (K/m) obtained by dividing the dynamic spring constant K of the vibration isolation base 230 by the rubber weight m of the vibration isolation base 230, and therefore, the natural frequency of the vibration isolation base 230 is increased by increasing the value of the dynamic spring constant and increased by reducing the weight of the vibration isolation base 230, and therefore, the natural frequency of the vibration isolation base 230 can be set higher by reducing the vibration isolation base 230 by forming the recess 233b, and thus, in the electric automobile vibration isolation device 200, the natural frequency of the vibration isolation base 230 can be set higher than the vibration frequency of a predetermined range (range of C1 to C2 in fig. 2 (b)) generated by driving the driving source such as the motor (set in the vicinity of C4 in fig. 2).

Similarly to the elastic deformation portion 33 of the first embodiment, the elastic deformation portion 233 has a cross-sectional area of a cut surface that is set to a constant size at each position in the radial direction around the axis O when the elastic deformation portion 233 is continuously cut along the axis O in the circumferential direction. Accordingly, in the electric vehicle vibration isolator 200, similarly to the electric vehicle vibration isolator 100 according to the first embodiment, the characteristic of the load in the gravity direction with respect to the amount of deflection of the vibration isolator 230 can be easily made linear within the range of the amount of deflection of the vibration isolator 230 of ± 30% of the free length R2 of the vibration isolator 230.

In this case, since the inner surfaces of the recessed portion 233b facing each other in the radial direction are formed in an arc shape that is coaxial with the axis O in the axial O direction view, and the inner surfaces facing each other in the circumferential direction are formed in a linear plane extending in the radial direction from the axis O, the cross section of the cut surface in the case where the elastically deformable portion 233 is continuously cut in the circumferential direction along the axis O at each position in the radial direction around the axis O can be easily set to a constant size at each position in the radial direction. As a result, in the anti-vibration device 200 for an electric vehicle, the characteristic of the load in the gravity direction with respect to the amount of deflection of the anti-vibration base 230 can be easily made linear in the range of ± 30% of the amount of deflection of the anti-vibration base 230 of the free length R2 of the anti-vibration base 230.

Further, since the cutout 233b is formed to pass through the first film portion 31 to the second film portion 32 in the radial direction about the axis O, the internal space of the cutout 233b can be increased and the vibration isolating base 230 can be reduced. Therefore, in the anti-vibration device 200 for an electric vehicle, the natural frequency of the anti-vibration base 230 can be easily set higher (set near C4 in fig. 2 b) than the vibration frequency (the range of C1 to C2 in fig. 2 b) of the predetermined range input to the anti-vibration base 230 by driving the drive source such as the motor. As a result, in the anti-vibration device 200 for an electric vehicle, the dynamic spring constant of the anti-vibration device 200 for an electric vehicle can be increased to a predetermined value (K1 in fig. 2 (b)) or more by suppressing the resonance of the anti-vibration base 230.

Next, a vibration isolator 300 for an electric vehicle according to a third embodiment will be described with reference to fig. 4. In the second embodiment, the case where the inside of the depressed portion 233b is formed as a space has been described, but in the third embodiment, the case where the coupling portion 333e that couples the inner surfaces of the depressed portion 233b is formed has been described. Note that the same portions as those in the above embodiments are denoted by the same reference numerals, and description thereof is omitted.

Fig. 4 (a) is a side view of an electric vehicle vibration isolator 300 according to a third embodiment, and fig. 4 (b) is a cross-sectional view of the electric vehicle vibration isolator 300 taken along line IVb-IVb in fig. 4 (a).

As shown in fig. 4, the vibration isolator 300 for an electric vehicle according to the third embodiment is a bush provided between a drive source such as a motor and a vehicle body. The vibration isolation device 300 for an electric vehicle includes: the vibration-proof device includes a cylindrical inner tube member 10 formed of a metal material such as iron or aluminum and having an axis O, a cylindrical outer tube member 20 disposed concentrically with the inner tube member 10 and formed of a metal material such as iron or aluminum, and a vibration-proof base 330 formed of a rubber-like elastic material and connecting an outer circumferential surface of the inner tube member 10 and an inner circumferential surface of the outer tube member 20.

The vibration isolator 300 for an electric vehicle is manufactured by vulcanization-bonding the vibration isolating base 330 between the inner tubular member 10 and the outer tubular member 20, and then reducing the diameter of the outer tubular member 20. Fig. 4 shows an electric vehicle vibration isolator 300 in which the outer tubular member 20 is reduced in diameter.

The vibration-proof base 330 includes: a first film portion 31 covering the outer peripheral surface of the inner tube member 10 with a constant thickness, a second film portion 32 covering the inner peripheral surface of the outer tube member 20 with a constant thickness, and an elastic deformation portion 333 connecting the first film portion 31 and the second film portion 32.

The elastically deformable portion 333 includes a reinforcing portion 33a formed at a corner portion of a connecting portion to the first film portion 31 and the second film portion 32, a recessed portion 233b formed to penetrate along the axis O direction outside the horizontal direction of the inner tube member 10 (the horizontal direction of the inner tube member 10) perpendicular to the axis O direction (the direction of the arrow L-R) in a state where the electric vehicle vibration damping device 300 is mounted on the vehicle body of the vehicle, an upper side elastic portion 233c on the upper side and a lower side elastic portion 233D on the lower side separated by the recessed portion 233b in the gravity direction (the direction of the arrow U-D), and a connecting portion 333e connected between inner surfaces of the recessed portion 233b from the upper side elastic portion 233c to the lower side elastic portion 233D.

The connecting portion 333e improves the vibration damping effect at a vibration frequency of a predetermined range or more, suppresses resonance of the upper elastic portion 233c and the lower elastic portion 233d at a vibration frequency of a predetermined range or more, and suppresses an increase in the dynamic spring constant of the vibration damping device 300 for an electric vehicle. The coupling portion 333e is coupled between the circumferentially opposite inner surfaces of the recessed portion 233b in the axial O direction in view at a substantially central position between the inner tubular member 10 and the outer tubular member 20 (a substantially intermediate position in the radial direction of the inner surfaces of the recessed portions 233b that are circumferentially opposite to each other).

The coupling part 333e extends parallel to a plane orthogonal to the axis O, and the coupling part 333e is formed substantially at the center of the depressed part 233b in the axis O direction (the direction of the arrow L-R) and inside both end surfaces of the vibration-proof base 330 in the axis O direction, whereby a planar stepped surface 333b1 extending along the axis O direction is formed on the inner surface of the depressed part 233b from the coupling part of the coupling part 333e and the depressed part 233b to both end surfaces of the vibration-proof base 330 in the axis O direction in the depressed part 233 b.

Here, in the antivibration device 200 for an electric vehicle described in the second embodiment, the recessed portion 233b penetrating in the axis O direction is provided in the region radially outside the inner tube member 10 in the horizontal direction orthogonal to the axis O direction (the direction of the arrow L-R), so that the natural frequency of the antivibration base 230 can be set higher (in the vicinity of C4 in fig. 2 b) than the frequency of the predetermined range (C1 to C2 in fig. 2 b) generated by driving the drive source, and the resonance of the antivibration base 230 can be suppressed.

However, as shown by the line Y in fig. 2b, in the vibration isolator 200 for an electric vehicle according to the second embodiment, when the vibration isolation base 230 is input at a vibration frequency within a predetermined range or more (in the vicinity of C4 in fig. 2 b), the dynamic spring constant still increases (the dynamic spring constant increases to the vicinity of K1 in fig. 2 b). Therefore, in the vibration isolator 200 for an electric vehicle, when the rotation speed of the drive source is increased and the frequency of vibration input from the drive source is set to be equal to or higher than a predetermined range (in the vicinity of C4 in fig. 2 (b)), there is a risk that: the natural frequency of vibration isolation base 230 falls within a predetermined range of the vibration frequency of input vibration isolation base 230, and the dynamic spring constant of vibration isolation device 200 for an electric vehicle is rapidly increased.

In contrast, in the third embodiment, since the connecting portion 333e that is connected between the circumferentially opposing inner surfaces of the recessed portion 233b in the axial O direction view and that has a smaller volume than the upper-side elastic portion 233C and the lower-side elastic portion 233d is formed, the connecting portion 333e can be made to resonate at a vibration frequency (a vibration frequency in the vicinity of C3 where the dynamic spring constant increases in the line Z of fig. 2 (b)) that is smaller than the predetermined value at which the upper-side elastic portion 233C and the lower-side elastic portion 233d can resonate easily. Thus, in the anti-vibration device 300 for an electric vehicle, the anti-vibration effect of the connecting portion 333e can be improved at a vibration frequency higher than the vibration frequency at which the connecting portion 333e is likely to resonate (the vibration frequency in the range where the dynamic spring constant becomes lower as the vibration frequency becomes higher in the line Z of fig. 2 (b) (the vibration frequency in the range of C3 to C4 of fig. 2)), and the predetermined value of vibration frequency at which the upper elastic portion 233C and the lower elastic portion 233d are likely to resonate can be included in the range of vibration frequencies at which the anti-vibration effect is improved.

As a result, at a vibration frequency within a predetermined range or more (a range of C2 or more in fig. 2 (b)), the coupling part 333e improves the vibration damping effect, suppresses resonance of the upper elastic part 233C and the lower elastic part 233d, and suppresses a rapid increase in the dynamic spring constant of the vibration damping device 300 for an electric vehicle.

Further, since the step surface 333b1 is formed on the inner surface of the recessed portion 233b and the connecting portion 333e is set at the substantially central position in the axis O direction (the direction of the arrow L-R) of the recessed portion 233b, the direction of the force input to the connecting portion 333e when the upper elastic portion 233c or the lower elastic portion 233D is deformed can be easily made to act on the extending direction (the direction of the arrow U-D) of the connecting portion 333e, that is, in the anti-vibration device 300 for an electric vehicle, the direction of the force input to the connecting portion 333e can be suppressed from being inclined toward the axis O direction.

Therefore, in the vibration isolator 300 for an electric vehicle, it is possible to suppress a problem that the coupling part 333e is deflected in the axis O direction (the direction of the arrow L-R), and the elastic restoring force of the coupling part 333e acts in the axis O direction, and the required characteristics of the vehicle cannot be satisfied.

The vibration-proof base 330 other than the recessed portion 233b has a cross-sectional area of a cut surface in a case where the elastic deformation portion 333 is continuously cut along the axis O in the circumferential direction at each position in the radial direction around the axis O, the cross-sectional area being set to a constant size at each position in the radial direction. Further, since the coupling part 333e is coupled to the inner surface of the recessed part 233b at a substantially central position between the inner tubular member 10 and the outer tubular member 20 in the axial O direction view (at a substantially intermediate position in the radial direction of the inner surface of the recessed part 233b facing in the circumferential direction), the forces acting on the end surface of the coupling part 333e in the extending direction (the arrow U-D direction) from the upper elastic part 233c and the lower elastic part 233D can be easily equalized.

Before the outer tubular member 20 is reduced in diameter (after the vibration-proof base 330 is vulcanized and bonded between the inner tubular member 10 and the outer tubular member 20), the coupling portion 333e extends linearly in the axial O direction, and in the state after the outer tubular member 20 is reduced in diameter, the coupling portion 333e is pressed by the upper elastic portion 233c and the lower elastic portion 233d and is deformed radially outward.

Therefore, in the anti-vibration device 300 for an electric vehicle, the connecting portion 333e is formed linearly before the diameter reduction processing of the outer cylindrical member 20, and therefore, the weight of the connecting portion 333e can be reduced compared to the case where the connecting portion 333e is formed into a curved shape before the diameter reduction processing of the outer cylindrical member 20.

Therefore, in the anti-vibration device 300 for an electric vehicle, the natural frequency of the anti-vibration base 330 (the upper elastic portion 233c and the lower elastic portion 233d) in the portion other than the connecting portion 333e can be easily set to a value different from the natural frequency of the connecting portion 333 e. As a result, in the anti-vibration device 300 for an electric vehicle, when vibration due to driving of the drive source is input, the upper elastic portion 233C and the lower elastic portion 233d and the connection portion 333e can be easily caused to perform different operations, so that resonance of the upper elastic portion 233C and the lower elastic portion 233d at a vibration frequency within a predetermined range or more (C2 in fig. 2b or more) is suppressed, and the dynamic spring constant is suppressed from becoming a predetermined value or more by the connection portion 333 e.

In the present embodiment, as shown by the line Z in fig. 2 (b), when the vibration isolation base 330 is input at a vibration frequency within a predetermined range or more (in the vicinity of C4 in fig. 2 (b)), the dynamic spring constant becomes maximum, but the dynamic spring constant can be suppressed to a predetermined value (K1 in fig. 2 (b)) or less.

The width of the connecting portion 333e in the axial O direction in the direction perpendicular to the extending direction (arrow U-D direction) is set to be in the range of 1/5 to 1/3 with respect to the width of the notch 233b in the radial direction. This is because the strength of elastic deformation of the coupling part 333e with respect to the radial direction can be ensured by setting the width of the coupling part 333e to 1/5 or more, and the following problems can be suppressed by setting the width of the coupling part 333e to 1/3 or less: when the coupling portion 333e is elastically deformed, the coupling portion 333e comes into contact with the outer peripheral surface of the inner tube member 10 or the inner peripheral surface of the outer tube member 20, and the dynamic spring constant changes irregularly.

Further, the width of the coupling part 333e in the direction of the axis O (the direction of the arrow L-R) is set in accordance with the relationship of the width of the coupling part 333e in the view angle in the direction of the axis O in the direction orthogonal to the extending direction (the direction of the arrow U-D) so that the sectional area of the cut surface when the coupling part 333e is cut along the direction of the axis O by the plane passing through the axis O is 1/5 or less with respect to the sectional area when the vibration damping base 330 (excluding the indentation 233 b) is cut along the direction of the axis O by the plane passing through the axis O, because the difference between the natural frequency of the upper elastic part 233c and the lower elastic part 233D (the vibration damping base 330 excluding the indentation) and the natural frequency of the coupling part 333e can be increased by setting the sectional area of the coupling part 333e to 1/5 or less of the sectional area of the vibration damping base 330.

Next, a vibration damping device 400 for an electric vehicle according to a fourth embodiment will be described with reference to fig. 5 and 6. In the fourth embodiment, a case will be described where the clip member 440 is inserted into the recessed portion 233b of the anti-vibration device for electric vehicle 300 according to the third embodiment. Note that the same portions as those in the above embodiments are denoted by the same reference numerals, and description thereof is omitted.

Fig. 5 (a) is a front view of a part of an electric vehicle vibration isolator 400 and a mounting bracket 450 according to a fourth embodiment, and fig. 5 (b) is an exploded perspective front view of the electric vehicle vibration isolator 400. Fig. 6 (a) is a sectional view of the antivibration device 400 for an electric vehicle taken along line VIa-VIa in fig. 5 (a), and fig. 6 (b) is a sectional view of the antivibration device 400 for an electric vehicle taken along line VIb-VIb in fig. 6 (a).

In fig. 5 (a), a part of the mounting bracket 450 for mounting the vibration isolator 400 for an electric vehicle, and the bolt B and the nut N for mounting the mounting bracket 450 are shown by broken lines.

As shown in fig. 5 and 6, the vibration isolator 400 for an electric vehicle according to the fourth embodiment is a bush provided between a drive source such as a motor and a vehicle body, and the vibration isolator 400 for an electric vehicle includes a cylindrical inner tube member 10 formed of a metal material such as iron or aluminum and having an axis O, an outer tube member 20 disposed concentrically with the inner tube member 10 and formed of a metal material such as iron or aluminum and having a cylindrical shape, a vibration isolating base 330 formed of a rubber-like elastic body and connecting an outer peripheral surface of the inner tube member 10 and an inner peripheral surface of the outer tube member 20, and a clamping member 440 formed of the same rubber-like elastic body as the vibration isolating base 330 and disposed on both outer sides of the outer tube member 20 in the axis O direction (the direction of an arrow L-R).

The mounting bracket 450 mainly includes: a drive side bracket 451 connected to a drive source of an electric vehicle such as an electric motor, and a vehicle side bracket 452 connected to a vehicle body of the vehicle. The driving bracket 451 is formed by inserting a bolt B into the cylindrical inner tube member 10 and fastening the inner tube member 10 from the opposite side with a nut N. The outer tube member 20 is pushed inward and coupled to the vehicle body side bracket 452.

Further, a suppression member 451a formed of a rubber-like elastic body is disposed on the drive side bracket 451 on the side of the anti-vibration device 400 for an electric vehicle. The suppression member 451a suppresses the outer cylindrical member 20 from abutting the driving bracket 451 when it is displaced toward the driving bracket 451. As a result, in the vibration damping device 400 for an electric vehicle, deformation and breakage of the outer tube member 20 can be suppressed.

The clamping member 440 includes a flat plate portion 441 formed in a flat plate shape having a flat surface in a direction perpendicular to the axis O direction (the direction of arrow L-R), and an abutting portion 442 provided to protrude from the flat surface of the flat plate portion 441 in the axis O direction and inserted into the concave portion 233b of the vibration-proof base 330.

The flat plate portion 441 is formed in a rectangular flat plate shape that is long in one direction, is set to have a dimension in the longitudinal direction larger than the diameter of the outer cylindrical member 20, and is disposed in a state in which both ends in the longitudinal direction protrude radially outward from the outer cylindrical member 20. The flat plate portion 441 is disposed coaxially with the shaft O, and has a through hole 441a penetrating in a circular shape.

The through hole 441a is formed to have substantially the same or slightly smaller outer diameter than the first film portion 31 covering the outer peripheral surface of the inner cylindrical member 10. Therefore, the clamping member 440 is disposed on the inner tube member 10 by pressing the inner tube member 10 into the through hole 441a (fitting externally to the inner tube member 10).

The contact portion 442 is formed in a substantially triangular shape smaller than the inner contour of the cutout 233b in the axial O direction, and in a state where the flat plate portion 441 is in contact with the end surface of the outer cylindrical member 20 in the axial O direction (the direction of the arrow L-R) (a state where the holding member 440 is externally fitted to the inner cylindrical member 10), the protruding tip end surface of the contact portion 442 protrudes to a position facing the end surface of the coupling portion 333e in the axial O direction with a predetermined gap therebetween, that is, the contact portion 442 is set so as not to be in contact with the coupling portion 333 e.

Further, the contact portion 442 is disposed with a predetermined gap S (see fig. 6 b) from the inner surface of the recessed portion 233b in the axial O direction.

The predetermined gap S is a position where the distance between the inner surface of the recessed portion 233b and the contact portion 442 in the gravity direction (the direction of the arrow U-D) is the smallest, and is set to a distance: when a load in a predetermined range acts on the vibration isolation device 400 for an electric vehicle in the direction of gravity and the vibration isolation base 330 flexes within a range of ± 30% of the free length by the flexing amount, the inner surface of the recessed portion 233b does not abut against the abutting portion 442. Thus, in the anti-vibration device 400 for an electric vehicle, when a load in a predetermined range acts in the direction of gravity, the inner surface of the recessed portion 233b abuts against the contact portion 442, and the dynamic spring constant is prevented from rapidly increasing (that is, the characteristic of the load in the direction of gravity with respect to the amount of deflection of the anti-vibration base 330 can be kept linear).

Here, in the antivibration devices 200 and 300 for electric vehicles described in the second and third embodiments, since the recessed portion 233b is formed, when a load in the horizontal direction orthogonal to the axis O direction (the direction of the arrow L-R) is input, the inner tube member 10 is easily displaced in the horizontal direction with respect to the outer tube member 20, and therefore, in the antivibration devices 200 and 300 for electric vehicles, the amount of elastic deformation in the horizontal direction of the antivibration base bodies 230 and 330 becomes large, and it becomes difficult to ensure the durability of the antivibration devices 200 and 300 for electric vehicles.

In view of this problem, in the fourth embodiment, since the abutting portion 442 inserted inside the recessed portion 233b is provided, when a load acts in the horizontal direction orthogonal to the axis O direction (the direction of the arrow L-R), the inner surface of the recessed portion 233b abuts against the abutting portion 442, whereby the displacement of the inner tube member 10 relative to the outer tube member 20 in the horizontal direction can be suppressed.

In the fourth embodiment, since the contact portions 442 are formed of a rubber-like elastic body, the force in the case where a load acts in the horizontal direction orthogonal to the axis O direction (the direction of the arrow L-R) and the inner surfaces of the recessed portions 233b are brought into contact with the contact portions 442 can be dispersed to both the contact portions 442 and the vibration isolating base 330.

Next, a vibration isolator 500 for an electric vehicle according to a fifth embodiment will be described with reference to fig. 7. In the fourth embodiment, the case where the abutting part 442 protrudes to the front of the coupling part 333e has been described, but in the fifth embodiment, the case where the second convex part 542b protruding to the position overlapping with the coupling part 333e in the radial direction is formed has been described. Note that the same portions as those in the above embodiments are denoted by the same reference numerals, and description thereof is omitted.

Fig. 7 (a) is a cross-sectional view of an electric vehicle vibration isolator 500 according to a fifth embodiment, and fig. 7 (b) is a cross-sectional view of the electric vehicle vibration isolator 500 taken along line VIIb-VIIb in fig. 7 (a). The cross section of the anti-vibration device for electric vehicle 500 in fig. 7 (a) corresponds to the cross section of the anti-vibration device for electric vehicle 400 in fig. 5 (b).

As shown in fig. 7, the vibration isolator 500 for an electric vehicle according to the fifth embodiment is a bush provided between a drive source such as a motor and a vehicle body, and the vibration isolator 500 for an electric vehicle includes a cylindrical inner tube member 10 formed of a metal material such as iron or aluminum and having an axis O, an outer tube member 20 disposed concentrically with the inner tube member 10 and formed of a metal material such as iron or aluminum and having a cylindrical shape, a vibration isolating base 330 formed of a rubber-like elastic body and connecting an outer peripheral surface of the inner tube member 10 and an inner peripheral surface of the outer tube member 20, and clamping members 540 formed of the same rubber-like elastic body as the vibration isolating base 330 and disposed on both outer sides of the outer tube member 20 in the axis O direction (the direction of arrow L-R).

The clamping member 540 includes a flat plate portion 441 formed in a flat plate shape having a plane orthogonal to the axis O, and an abutting portion 542 provided to protrude from the plane of the flat plate portion 441 in the axis O direction (the direction of arrow L-R) and inserted into the recessed portion 233b of the vibration-proof base 330.

The abutting portion 542 is formed in a substantially triangular shape having a smaller inner contour than the cutout portion 233b in the axial O direction, and includes a first projecting portion 542a projecting from the flat plate portion 441, and a pair of second projecting portions 542b projecting further in the axial O direction (the direction of arrow L-R) from the tip of the first projecting portion 542 a.

In a state where the flat plate portion 441 is in contact with an end surface of the outer cylindrical member 20 in the axis O direction (the direction of arrow L-R) (a state where the holding member 540 is fitted to the outer cylindrical member 10), the projecting distal end surface of the first projecting portion 542a projects to a position spaced apart from the end surface of the coupling portion 333e in the axis O direction by a predetermined gap.

The second projecting portion 542b projects in the axial O direction (direction of arrow L-R) from both sides sandwiching the coupling portion 333e in the radial direction at a position radially spaced apart from the coupling portion 333e by a predetermined gap in the axial O direction, and the second projecting portion 542b projects to a substantially central position of the vibration isolation base 330 in the axial O direction.

That is, the second projection 542b projects to a position overlapping the coupling part 333e in the radial direction. Thus, in the anti-vibration device 500 for an electric vehicle, when the coupling portion 333e is elastically deformed in the radial direction, the coupling portion 333e can be brought into contact with the second convex portion 542b, and the elastic deformation of the coupling portion 333e can be suppressed.

Therefore, in the anti-vibration device 500 for an electric vehicle, it is possible to improve the anti-vibration effect of the connecting portion 333e, and to suppress the resonance of the upper-side elastic portion 233c and the lower-side elastic portion 233d of the anti-vibration base 330 at the vibration frequency of the predetermined range or more generated by the driving of the vibration source, and in this case, it is possible to suppress the elastic deformation of the connecting portion 333e and the reduction of the anti-vibration effect of the connecting portion 333 e.

Therefore, in the anti-vibration device 500 for an electric vehicle, since it is not necessary to increase the outer shape of the connecting portion 333e in order to suppress elastic deformation of the connecting portion 333e, the weight of the connecting portion 333e can be reduced, and the natural frequencies of the upper elastic portion 233c and the lower elastic portion 233d and the natural frequency of the connecting portion 333e can be easily set to different values. As a result, in the vibration isolation device 500 for an electric vehicle, the vibration isolation base 330 can be suppressed from resonating at a vibration frequency within a predetermined range generated by driving of the drive source.

Next, a vibration isolator 600 for an electric vehicle according to a sixth embodiment will be described with reference to fig. 8 (a). In the third embodiment, the case where the coupling portion 333e is formed linearly parallel to the plane orthogonal to the axis O before the outer tubular member 20 is subjected to the diameter reducing process has been described, but the coupling portion 633e of the sixth embodiment is provided to extend in the circumferential direction around the axis O. Note that the same portions as those in the above embodiments are denoted by the same reference numerals, and description thereof is omitted.

Fig. 8 (a) is a side view of an electric vehicle vibration isolator 600 according to a sixth embodiment. As shown in fig. 8 (a), an electric vehicle vibration isolator 600 according to a sixth embodiment is a bush provided between a drive source such as a motor and a vehicle body. The vibration isolation device 600 for an electric vehicle includes: the vibration-proof device includes a cylindrical inner tube member 10 formed of a metal material such as iron or aluminum and having an axis O, a cylindrical outer tube member 20 disposed concentrically with the inner tube member 10 and formed of a metal material such as iron or aluminum, and a vibration-proof base 630 formed of a rubber-like elastic material and connecting an outer circumferential surface of the inner tube member 10 and an inner circumferential surface of the outer tube member 20.

The vibration isolator 600 for an electric vehicle is manufactured by vulcanization-bonding the vibration isolating base 630 between the inner tubular member 10 and the outer tubular member 20, and then reducing the diameter of the outer tubular member 20. Fig. 8 (a) shows an electric vehicle vibration isolator 600 in which the outer tubular member 20 is reduced in diameter.

The vibration-proof base 630 includes: a first film portion 31 covering the outer peripheral surface of the inner tube member 10 with a constant thickness, a second film portion 32 covering the inner peripheral surface of the outer tube member 20 with a constant thickness, and an elastic deformation portion 633 connecting the first film portion 31 and the second film portion 32.

The elastic deformation portion 633 is provided with a reinforcement portion 33a (see fig. 4 (b)) formed at a corner portion of a connection portion connected to the first film portion 31 and the second film portion 32, a recessed portion 233b formed to penetrate along the axis O direction outside (in the horizontal direction of the inner tube member 10) of the horizontal direction orthogonal to the axis O direction (the direction of arrow L-R) in a state where the electric vehicle vibration isolator 600 is mounted on the vehicle body of the vehicle, an upper side elastic portion 233c on the upper side and a lower side elastic portion 233D on the lower side separated from the recessed portion 233b in the gravity direction (the direction of arrow U-D), and a connection portion 633e connected between inner surfaces of the recessed portion 233b from the upper side elastic portion 233c to the lower side elastic portion 233D.

The connecting portion 633e improves the vibration damping effect at a vibration frequency of a predetermined range or more, suppresses resonance of the upper side elastic portion 233c and the lower side elastic portion 233d, and suppresses an increase in the dynamic spring constant of the vibration damping device 600 for an electric vehicle, the connecting portion 633e is connected to the upper side elastic portion 233c and the lower side elastic portion 233d at a substantially central position between the inner tube member 10 and the outer tube member 20 (substantially at a radially intermediate position of the inner surface of the circumferentially opposing indentation 233 b) in an axial O direction view, the connecting portion 633e extends in a circumferential direction around the axis O with a constant width, and the width in the axial O direction (the direction of an arrow L-R) is set constant.

Therefore, in the anti-vibration device 600 for an electric vehicle according to the sixth embodiment, the connection portion 633e can be easily elastically deformed in accordance with the elastic deformation of the anti-vibration base 630, as compared to the connection portion 333e formed linearly.

Next, a vibration isolator 700 for an electric vehicle according to a seventh embodiment will be described with reference to fig. 8 (b). In the above-described vibration damping device 600 for an electric vehicle according to the sixth embodiment, a description has been given of a case where the connection portions 633e extend in the circumferential direction around the axis O by the same width, and a description has been given of a case where a portion of the vibration damping device 700 for an electric vehicle according to the seventh embodiment that extends in the circumferential direction is partially thickened. Note that the same portions as those in the above embodiments are denoted by the same reference numerals, and description thereof is omitted.

Fig. 8 (b) is a side view of an electric vehicle vibration isolator 700 according to a seventh embodiment. As shown in fig. 8 (b), an electric vehicle vibration isolator 700 according to a seventh embodiment is a bush provided between a drive source such as a motor and a vehicle body. The vibration isolation device 700 for an electric vehicle includes: the vibration-proof device includes a cylindrical inner tube member 10 formed of a metal material such as iron or aluminum and having an axis O, a cylindrical outer tube member 20 disposed concentrically with the inner tube member 10 and formed of a metal material such as iron or aluminum, and a vibration-proof base 730 formed of a rubber-like elastic material and connecting an outer circumferential surface of the inner tube member 10 and an inner circumferential surface of the outer tube member 20.

The vibration isolator 700 for an electric vehicle is manufactured by vulcanization-bonding the vibration isolating base 730 between the inner tubular member 10 and the outer tubular member 20, and then reducing the diameter of the outer tubular member 20. Fig. 8 (b) shows an electric vehicle vibration isolator 700 in which the outer tube member 20 is reduced in diameter.

The vibration-proof base 730 includes: a first film portion 31 covering the outer peripheral surface of the inner tube member 10 with a constant thickness, a second film portion 32 covering the inner peripheral surface of the outer tube member 20 with a constant thickness, and an elastic deformation portion 733 connecting the first film portion 31 and the second film portion 32.

The elastically deformable portion 733 includes a reinforcing portion 33a (see fig. 4 (b)) formed at a corner portion of a connecting portion connecting the first film portion 31 and the second film portion 32, a depressed portion 233b formed to penetrate along the axis O direction outside (horizontal direction of the inner tube member 10) of the horizontal direction orthogonal to the axis O direction (direction of arrow L-R) in a state where the electric vehicle vibration isolator 700 is disposed in a vehicle body of the vehicle, an upper side elastic portion 233c on an upper side and a lower side elastic portion 233D on a lower side separated by the depressed portion 233b in a gravitational direction (direction of arrow U-D), and a connecting portion 733e connected between inner surfaces of the depressed portion 233b from the upper side elastic portion 233c to the lower side elastic portion 233D.

The connection portion 733e improves the vibration damping effect at a vibration frequency of a predetermined range or more, suppresses resonance of the upper elastic portion 233c and the lower elastic portion 233d, and suppresses an increase in the dynamic spring constant of the vibration damping device 700 for an electric vehicle. The connection portion 733e connects the upper elastic portion 233c and the lower elastic portion 233d, and connects the upper elastic portion 233c and the lower elastic portion 233d at substantially the center between the inner surfaces of the recessed portion 233b facing each other in the circumferential direction (at substantially the middle position in the radial direction of the inner surface of the recessed portion 233b facing each other in the circumferential direction) of the inner tubular member 10 and the outer tubular member 20 between the inner surfaces facing each other in the axial O direction.

The connection portion 733e extends in the circumferential direction around the axis O, and has a constant width in the axis O direction (the direction of the arrow L-R). in addition, the connection portion 733e includes a protruding portion 733e1 protruding toward the axis O (the inner tube member 10) at a substantially intermediate position extending in the circumferential direction in the view of the axis O direction.

The projection 733e1 is a portion that suppresses displacement of the inner tube member 10 in the horizontal direction, and is formed in a region that overlaps the inner tube member 10 in a direction orthogonal to the axis O direction (arrow L-R direction).

Thus, in the anti-vibration device 700 for an electric vehicle, when the inner tubular member 10 is displaced in the horizontal direction orthogonal to the axis O direction (the direction of the arrow L-R), the inner tubular member 10 can be brought into contact with the protruding portion 733e1, and the protruding portion 733e1 can be gradually deformed, and as a result, in the anti-vibration device 700 for an electric vehicle, an increase in the load of the connection portion 733e when the inner tubular member 10 is brought into contact with the connection portion 733e can be alleviated.

The projection distance of the projection 733e1 in the axial O direction view is set radially outward of a straight line connecting both ends of the connection part 733e in the circumferential direction. Thus, in the anti-vibration device 700 for an electric vehicle, it is possible to suppress the connection portion 733e from becoming less likely to elastically deform in a direction approaching the inner circumferential surface of the outer tube member 20. That is, in the anti-vibration device 700 for an electric vehicle, it is possible to suppress the force input from one end surface in the extending direction of the connection portion 733e from being linearly transmitted to the other end surface in the extending direction via the projection 733e 1.

The present invention has been described above based on the above embodiments, but the present invention is not limited to the above embodiments at all, and it can be easily inferred that various modifications and improvements can be made within the scope not departing from the gist of the present invention.

For example, the numerical values listed in the above embodiments are merely examples, and it is needless to say that other numerical values may be adopted.

In the above embodiments, the description has been given of the case where the anti-vibration device for electric vehicle 100, 200, 300, 400, 500, 600, 700 is provided in an electric vehicle, but the anti-vibration device for electric vehicle 100, 200, 300, 400, 500, 600, 700 may be used in an internal combustion engine type vehicle such as a gasoline engine or a diesel engine.

In this case, in the anti-vibration devices 200, 300, 400, 500, 600, and 700 for electric vehicles according to the second to seventh embodiments, depending on the load characteristics acting on the internal combustion engine type vehicle and the vibration characteristics of the gasoline engine, the diesel engine, and the like, the anti-vibration devices 100, 200, 300, 400, 500, 600, and 700 for electric vehicles may be arranged on the vehicle body of the internal combustion engine type vehicle in a state in which the anti-vibration base bodies 230, 330, 630, and 730 are not formed with the through holes at the positions overlapping the inner tube member 10 in the horizontal direction and the recessed portions penetrating in the axial direction are formed in the regions outside the inner tube member 10 in the gravity direction.

Accordingly, since the vibration isolation base 30, 230, 330, 630, 730 does not have a through hole at a position overlapping the inner tube member 10 in the horizontal direction, the dynamic spring constant of the vibration isolation device 100, 200, 300, 400, 500, 600, 700 for the electric vehicle can be suppressed from increasing to a predetermined value or more when a load acts in the horizontal direction.

In the above embodiments, the description has been given of the case where the axial O direction is arranged in the left-right direction (the direction of arrow L-R) with respect to the vehicle body of the vehicle with respect to the antivibration devices 100, 200, 300, 400, 500, 600, 700 for electric vehicles, but the axial O direction is not necessarily limited thereto, and may be arranged in the front-rear direction (the direction of arrow F-B) as long as the vertical direction (the direction of arrow U-D) is the same.

In the second to seventh embodiments in this case, in consideration of the ease of input of a load in the front-rear direction (the direction of the arrow F-B), the shapes of the pair of recessed portions 233B or the shapes of the coupling portions 333e, 633e, 733e coupled to the inside of the recessed portions 233B may be changed to shapes different in the front-rear direction, so that the vibration isolating bases 230, 330, 630, 730 may have different deformability with respect to the front-rear load.

In the above embodiments, the case where the thickness of the vibration isolation base 30, 230, 330, 630, 730 is reduced from the axis O toward the radially outer side has been described with respect to the vibration isolation device 100, 200, 300, 400, 500, 600, 700 for an electric vehicle, but the present invention is not necessarily limited thereto, and the vibration isolation base 30, 230, 330, 630, 730 may be formed so that the thickness of the center portion in the radial direction is minimized.

In the second embodiment, the case where the depressed portion 233b is formed so as to curve around the axis O in the view point in the axis O direction has been described, but the present invention is not necessarily limited thereto, and may be formed linearly along the gravity direction (the arrow U-D direction) or formed in an arc shape around a position different from the axis O.

In the third embodiment, the case where one connecting portion 333e, 633e, 733e is formed at one depressed portion 233b has been described, but the present invention is not necessarily limited thereto, and two or more connecting portions 333e, 633e, 733e may be formed at one depressed portion 233 b.

In the fourth and fifth embodiments, the case where the clamp members 440 and 540 having the abutting portions 442 and 542 formed thereon are externally fitted to the outer side of the inner tube member 10 has been described, but the present invention is not necessarily limited thereto, and for example, the clamp members 440 and 540 may be clamped and held between the drive side bracket 451 of the mounting bracket 450 (see fig. 5 a) to which the vibration isolation device 400 and 500 for an electric vehicle is mounted and the end face of the inner tube member 10 in the direction of the axis O (the direction of the arrow L-R).

In this case, the contact portions 442 and 542 of the sandwiching member 440 can be formed in the restraining member 451a of the driving bracket 451, which is disposed on the electric vehicle anti-vibration devices 400 and 500 side, and the sandwiching members 440 and 540 and the restraining member 451a can be formed of the same member. In other words, the restraining member 451a of the driving bracket 451, which is disposed on the electric vehicle anti-vibration devices 400 and 500, can be replaced with the clamping members 440 and 540, and the clamping members 440 and 540 can also serve as the restraining member 451 a. As a result, the cost for manufacturing the clamping members 440 and 540 can be reduced, and the assembling workability for arranging the clamping members 440 and 540 can be improved.

The clamping members 440 and 540 may be attached to a bracket 452 on the vehicle body side of the outer tube member 20 into which the vibration isolators 400 and 500 for electric vehicles are press-fitted (see fig. 5 (a)). For example, a through hole may be formed in the flat plate portion 441, and a bolt inserted into the through hole may be fastened to the bracket 452 on the vehicle side to attach the clamp members 440 and 540 to the bracket 452 on the vehicle side.

In this case, since only the clamping members 440 and 540 can be attached to the bracket 452 on the vehicle body side after the outer tube member 20 of the anti-vibration devices 400 and 500 for electric vehicles is press-fitted into the bracket 452 on the vehicle body side, it is not necessary to arrange the clamping members 440 and 540 simultaneously with the operation of arranging the bracket 451 on the driving side on the inner tube member 10. Therefore, the mounting of the clip member 440 to the anti-vibration device for electric vehicle 400 can be simplified.

In the fourth and fifth embodiments, the cases where the clamping members 440 and 540 on which the abutting portions 442 and 542 are formed of the same material as the vibration isolating base 330 have been described, but the present invention is not necessarily limited thereto. For example, the material of the clamping members 440 and 540 may be a material that is less elastically deformable than the material of the vibration isolation base 330, and the spring constant required for the vibration isolation devices 400 and 500 for an electric vehicle may be adjusted by the clamping members 440 and 540.

In the fourth embodiment, the case where the clamping member 440 is disposed in the anti-vibration device for electric vehicle 400 in which the connecting portion 333e is formed inside the recessed portion 233b has been described, but the present invention is not necessarily limited to this. The clamping member 440 may be disposed inside the recessed portion 233b where the connecting portion 333e (the anti-vibration device 200 for an electric vehicle according to the second embodiment) is not formed.

In the fifth embodiment, the case where the pair of second projecting portions 542b is formed so as to be sandwiched between both sides of the coupling portion 333e in the radial direction in the axial O direction is described, but the present invention is not necessarily limited to this, and one second projecting portion 542b may be formed inside or outside the coupling portion 333e in the radial direction in the axial O direction.

Description of the reference numerals

10-an inner barrel component; 20-an outer barrel component; 30. 230, 330, 630, 730-vibration-proof base; 233 b-indentation (Japanese: すぐり part); 333b 1-step surface; 333e, 633e, 733 e-connecting part; 440. 540-a clamping member; 442. 542-an abutment; 451 a-a restraining member (stop member); 542 b-second projections (projections); 733e1 — projection; 100. 200, 300, 400, 500, 600, 700-vibration isolator for electric vehicle.