vibration isolator

Abstract

Provided is a vibration isolation device capable of sufficiently ensuring durability even in a case where a load input in one direction and a load input in the opposite direction greatly differ. In the vibration isolation device 10, the main body rubber elastic body 16 is in a circular truncated cone shape and is provided with a recess 34 that is open at a lower surface, the central axis 22 of the inner member 12 is arranged eccentrically with respect to the central axis 32 of the outer cylinder member 14 in a direction perpendicular to the axis, the free length of the main body rubber elastic body 16 that links the inner member 12 and the outer cylinder member 14 on one side in the eccentric direction and the free length of the main body rubber elastic body 16 that links the inner member 12 and the outer cylinder member 14 on the other side in the eccentric direction differ from each other, and the lower end of the inner member 12 is not exposed from the recess 34, a continuous rubber 40 that covers the lower end of the inner member 12 and makes the main body rubber elastic body 16 on one side in the eccentric direction continuous with the main body rubber elastic body 16 on the other side in the eccentric direction is formed integrally with the main body rubber elastic body 16.

Description

Technical Field

[0001] The present invention relates to a vibration damping device, for example, for an engine mount for a car. Background Technology

[0002] As a vibration damping device used in applications such as engine mounts for automobiles, vibration damping devices with a structure in which an inner member is connected by a main body rubber elastomer and an outer cylinder member separately disposed on the outer periphery of the inner member have been known. Such a vibration damping device is also shown, for example, in Japanese Patent Application Publication No. 2020-051474 (Patent Document 1).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2020-051474 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] However, in such vibration damping devices, the load applied in one direction can differ significantly from the load applied in the opposite direction along a radial path orthogonal to the central axis. For example, an automotive engine mount is constructed by fixing the inner member to the power unit side and the outer cylinder member to the vehicle body side, with the central axis aligned vertically. In this case, the braking load applied by the inner member relative to the outer cylinder member towards the front of the vehicle along a radial path corresponding to the vehicle's longitudinal direction is sometimes very small compared to the acceleration load applied by the inner member relative to the outer cylinder member towards the rear of the vehicle.

[0008] Therefore, with the repeated application of loads to the main rubber elastomer, the deformation (deformation) and stress vary locally. It is difficult to ensure the durability of the parts that are repeatedly subjected to large deformation and stress, and there is a hidden danger that the durability of the parts may hinder the overall durability of the vibration damping device.

[0009] In addition, in order to address this problem, it was also studied that the thickness of the main rubber elastomer components was locally different, but this had adverse effects on the spring characteristics and reduced relative durability of the thin-walled parts. It was difficult to achieve sufficient results by simply adjusting the thickness of the main rubber elastomer components.

[0010] The present invention provides a novel vibration damping device that can fully ensure durability even when the load input in one direction is significantly different from the load input in the opposite direction in a radial direction orthogonal to the central axis.

[0011] means for solving problems

[0012] Hereinafter, preferred embodiments for mastering the present invention will be described. However, the embodiments described below are merely illustrative and can be appropriately combined with each other. Furthermore, the various constituent elements described in each embodiment can be identified and used as independently as possible, and can also be appropriately combined with any constituent elements described in other embodiments. Therefore, the present invention is not limited to the embodiments described below, and various other embodiments can be implemented.

[0013] The first method is a vibration damping device in which an inner component and an outer cylinder component separately disposed on the outer periphery of the inner component are connected by a main rubber elastomer. The main rubber elastomer is frustoconical and has a recess with an opening on its lower surface. The central axis of the inner component is eccentric relative to the central axis of the outer cylinder component in a direction perpendicular to the axis. The free length of the main rubber elastomer on one side of the eccentric direction in the opposing direction between the inner component and the outer cylinder component, and the free length of the main rubber elastomer on the other side of the eccentric direction in the opposing direction between the inner component and the outer cylinder component are different from each other. The lower end of the inner component does not protrude from the recess. The lower end of the inner component is covered by a continuous rubber that is integrally formed with the main rubber elastomer, such that the main rubber elastomer on one side of the eccentric direction and the main rubber elastomer on the other side of the eccentric direction are continuous.

[0014] According to this method, in a direction orthogonal to the central axis of the vibration damping device, the free lengths of the main rubber elastomer connecting the inner component and the outer cylinder component are different on the one side and the other side, which sandwich the inner component. Therefore, even when the magnitudes of the loads input on both sides in the direction perpendicular to the axis are different, it is possible to suppress excessive deformation and stress caused by the main rubber elastomer on one side, and to avoid a significant reduction in the durability of the vibration damping device due to local deformation and stress in the main rubber elastomer.

[0015] Furthermore, when the main rubber elastomer on the side perpendicular to the axis, which sandwiches the inner component, experiences significant deformation and stress, this stress is transmitted via continuous rubber to the main rubber elastomer on the other side perpendicular to the axis, which also sandwiches the inner component. This mitigates the concentration of deformation and stress on that side of the main rubber elastomer, thus dispersing the deformation and stress. Consequently, the durability of the main rubber elastomer and even the vibration damping device is improved.

[0016] The second method is based on the vibration damping device involved in the first method, wherein the installation center axis of the inner component is coaxial with the installation center axis of the outer cylinder component.

[0017] The third method is a vibration damping device that connects an inner component and an outer cylinder component separately arranged on the outer periphery of the inner component via a main rubber elastomer. The main rubber elastomer is truncated cone-shaped and has a recess with an opening on its lower surface. The vibration damping device is provided with a circumferential positioning part, which is used to position the vibration damping device circumferentially in the assembly state where the central axis of the vibration damping device is set to the vertical direction of the vehicle. The circumferential positioning part defines the longitudinal direction of the vehicle, and the component central axis of the inner component is eccentrically arranged relative to the component central axis of the outer cylinder component in the longitudinal direction of the vehicle. The free length of the main rubber elastomer extending forward from the inner component toward the outer cylinder component is different from the free length of the main rubber elastomer extending backward from the vehicle. When the vehicle accelerates, the free length of the main rubber elastomer on the side of the displacement of the inner component relative to the outer cylinder component is greater than the free length of the main rubber elastomer on the side of the displacement of the outer component.

[0018] In vehicle vibration damping devices, such as those used in automotive engine mounts, the system experiences a torque reaction force in addition to the acceleration G during acceleration. This results in a significantly larger input load compared to deceleration, making it difficult to ensure durability. The inventors have conducted extensive research into the causes of this issue. It is generally believed that the durability of the main rubber elastomer at the location of tensile deformation during load input is insufficient, and that cracking or other defects at the location of the main rubber elastomer subjected to tensile load during acceleration contribute to poor durability. However, it is clear that the cause is not so simple. Furthermore, it is known that, typically, increasing the free length and thickness of the main rubber elastomer on the side where tensile load is input during acceleration—that is, the side where the inner component separates from the outer cylinder component during vehicle acceleration—ensures increased rubber volume and thus improved durability. However, this not only fails to improve durability but also raises concerns about its adverse effects on axial vibration damping.

[0019] In the vibration damping device described herein, contrary to the conventional measures mentioned above, the free length of the main rubber elastomer is set to be larger on the side opposite to the side where the tensile load is input during acceleration, i.e., the side where the inner member approaches displacement relative to the outer cylinder member during vehicle acceleration. As a result, it is possible to suppress excessive deformation and stress caused by the main rubber elastomer on one side, and to avoid a significant reduction in the durability of the vibration damping device caused by local deformation and stress in the main rubber elastomer. This invention is based on the following new insight: when the loads applied to the front and rear sides of the vehicle while clamping the inner member are significantly different, on the side where the inner member approaches displacement relative to the outer cylinder member due to the larger input load (acceleration side), compared to the other side in the vehicle's longitudinal direction (deceleration side), the main rubber elastomer is compressed more and deforms around the inner member in the circumferential direction. Large deformation and stress in the shear direction are easily generated in the inner circumferential portion of the main rubber elastomer fixed to the inner member, which is a reason why it is difficult to ensure durability in existing engine mount structures.

[0020] Furthermore, in the vibration damping device based on this new insight, in contrast to conventional measures that typically ensure durability, the free length of the main rubber elastomer is set to be larger in the compression side portion when the vehicle accelerates under a load greater than that during deceleration. This suppresses the deformation of the main rubber elastomer that wraps around the inner component circumferentially with the compression deformation of this portion, thereby effectively reducing deformation and stress in the shear direction. As a result, durability can be improved without significantly impairing axial vibration damping performance.

[0021] The fourth method is based on the vibration damping device involved in the third method above, in any state before and during vehicle assembly, the mounting center axis of the inner component and the mounting center axis of the outer cylinder component are coaxial.

[0022] In this method, stress concentration and deformation of the main rubber elastomer caused by static input load in the assembly state can be prevented, and the desired effect produced by the eccentricity of the component center axis of the internal shaft component relative to the component center axis of the outer cylinder component can be stably achieved.

[0023] The fifth method is based on the vibration damping device of any of the first to fourth methods mentioned above, wherein the outer and inner circumferential surfaces of the main rubber elastomer are both circular in the cross section perpendicular to the axis.

[0024] According to this method, when a load perpendicular to the axis is applied, the deformation of the main rubber elastomer, which is accompanied by the approach displacement or separation displacement of the inner component and the outer cylinder component, can be generated at the same time, while localized deformation and stress concentration can be avoided more reliably, thereby achieving further improvement in durability.

[0025] The sixth method is based on the vibration damping device of any of the first to fifth methods, wherein the surface lengths of the two sides of the outer and inner peripheral surfaces of the main body rubber elastomer are different from each other in the eccentric direction of the component central axis of the inner component relative to the component central axis of the outer cylinder component.

[0026] According to this method, by making at least one of the outer and inner circumferential surfaces of the main rubber elastomer different on both sides of the eccentric direction of the component center axis of the inner component relative to the component center axis of the outer cylinder component, the free lengths of the main rubber elastomer on both sides of the eccentric direction can be set differently, thus improving the durability of the vibration damping device more reliably.

[0027] Invention Effects

[0028] According to the present invention, a vibration damping device can be provided that can adequately ensure durability even when the load input in one direction is significantly different from the load input in the opposite direction in a radial direction orthogonal to the central axis. Attached Figure Description

[0029] Figure 1 This is a perspective view showing a vibration damping device as one embodiment of the present invention.

[0030] Figure 2 yes Figure 1 A top view of the vibration damping device shown.

[0031] Figure 3 yes Figure 2 Sectional view III-III.

[0032] Figure 4 yes Figure 2 Sectional view IV-IV.

[0033] Figure 5 yes Figure 2 VV sectional view.

[0034] Figure 6 yes Figure 3 Sectional view VI-VI.

[0035] Figure 7 yes Figure 3 Sectional view VII-VII. Detailed Implementation

[0036] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0037] exist Figures 1 to 7 As one embodiment of the vibration damping device according to the present invention, an engine mount 10 for automobiles is shown. This engine mount 10 has a structure in which an inner member 12 and an outer cylinder member 14 are connected by a main body rubber elastomer 16. Furthermore, for example, by fixing a power unit (not shown) to the inner member 12 and a vehicle body (not shown) to the outer cylinder member 14, the power unit provides vibration damping support for the vehicle body. Additionally, the orientation of the engine mount 10 during vehicle assembly is not limited; in the following description, the vertical direction refers to the vertical direction. Figure 3 The up and down directions in the text refer to the left and right directions of the vehicle. Figure 2 The vertical direction in the text refers to the up-down direction, while the front-back direction refers to the vehicle's forward and backward directions. Figure 2 In this embodiment, the engine mount 10 is mounted in the vehicle in these directions, in the left and right directions.

[0038] More specifically, the inner component 12 is a rigid component formed of metal or fiber-reinforced synthetic resin, and has a fixing portion 18 for fixing the main rubber elastomer 16. The fixing portion 18 is a columnar portion extending in the vertical direction. In this embodiment, in Figure 6 The cross-section shown perpendicular to the axis has a circular cross-section. In particular, in this embodiment, the fixing portion 18 has a perfectly circular cross-section. The lower end portion of the fixing portion 18 is formed into a pointed shape with a rounded front end (approximately hemispherical), but the front end (lower end) may also have a flat surface extending in a direction perpendicular to the axis. At the upper end portion of the inner member 12, an outwardly projecting flange-like portion 20 is provided around the entire circumference.

[0039] Additionally, reference numeral 22 in the figure indicates the inner central axis, which is the axis of the component, located at the center point of the cross section perpendicular to the axis in the axial direction connecting the inner component 12. This inner central axis 22 extends in the vertical direction, and the inner component 12 in this embodiment has an outer peripheral surface that is formed in a rotationally symmetric shape around the inner central axis 22.

[0040] On the inner component 12, bolt holes 24 are provided extending axially downward from the upper end face for bolts (not shown) to be threaded. The power unit is fixed to the inner component 12 by fixing bolts threaded into these bolt holes 24. That is, a connection fixing point is provided on the power unit that allows connection to the vehicle body side via the engine mount 10, and this connection fixing point is fixed relative to the inner component 12 on the support central axis of the engine mount 10. Therefore, the bolt holes 24 in the inner component 12, serving as fixing points, are located on the central axis (external central axis 32 described later) of the outer cylinder component 14 and the main body rubber elastomer 16, which serve as the support central axis. Furthermore, the central axis of these bolt holes 24 is set as the inner mounting shaft 26 in the inner component 12, which serves as the mounting central axis for mounting the power unit. The inner mounting shaft 26 is offset (eccentric) relative to the inner central axis 22; in this embodiment, the inner mounting shaft 26 is located behind the inner central axis 22 and extends parallel to the vertical direction.

[0041] Furthermore, a pin-shaped protrusion 28, serving as a circumferential positioning portion, is provided on the upper end face of the inner member 12 for positioning the engine bracket 10 in the circumferential direction. This pin-shaped protrusion 28 is inserted into the power unit, for example, when the inner member 12 is fixed to the power unit. In this embodiment, the pin-shaped protrusion 28 is located to the left of the bolt hole 24, and the pin-shaped protrusion 28 and the bolt hole 24 are arranged side-by-side in the left-right direction. That is, in Figure 2 In the top view shown, the direction orthogonal to the direction in which the pin protrusion 28 and the bolt hole 24 are arranged is the front-rear direction. By aligning the pin protrusion 28 toward the left side of the vehicle, the front-rear direction of the vehicle on which the internal component 12 (engine bracket 10) and the engine bracket 10 are assembled can be defined.

[0042] The outer cylinder member 14 is a relatively thin cylindrical shape, and its diameter is larger than that of the inner member 12. In this embodiment, the outer cylinder member 14 is cylindrical, and particularly in this embodiment, such as... Figure 7 As shown, the outer cylinder member 14 has a circular cross-section. At the lower end of the outer cylinder member 14, an annular protruding inner flange 30 is provided on the inner circumference side throughout the entire circumference. In addition, the upper end of the outer cylinder member 14 extends slightly outward along the entire circumference.

[0043] Additionally, reference numeral 32 in the figure indicates the outer central axis, which is the center point of the cross section perpendicular to the axis in the cross section connecting the outer cylinder member 14 along the axial direction. This outer central axis 32 extends in the vertical direction, and the outer cylinder member 14 in this embodiment has an outer peripheral surface that is formed in a rotationally symmetric shape about the outer central axis 32.

[0044] On the outer peripheral surface of the outer cylinder member 14, a subframe or similar component on the vehicle body side, such as a generally cylindrical bracket (not shown), is inserted externally in a press-in state, thereby fixing the outer cylinder member 14 to the vehicle body via the subframe or similar component. That is, the outer peripheral surface of the outer cylinder member 14 is the outer fixing surface 33 of the component fixed to the vehicle body side. Furthermore, the central axis of the center point of the cross-section perpendicular to the axis in the axial direction connecting the outer fixing surface 33 is designated as the outer mounting axis of the outer cylinder member 14, serving as the mounting center axis for mounting to the vehicle body. In this embodiment, the outer central axis 32, which serves as the component center axis of the outer cylinder member 14, is coaxial with the outer mounting axis, which serves as the mounting center axis. Therefore, in this embodiment, the inner mounting axis 26, which serves as the mounting center axis of the inner component 12, is coaxial with the outer mounting axis (outer central axis 32), which serves as the mounting center axis of the outer cylinder member 14. Furthermore, although the engine mount 10 is shown in the figure in its state before being assembled to the vehicle, in the assembled state before being assembled to the vehicle, the inner mounting shaft 26 and the outer mounting shaft (outer central shaft 32) are also coaxial when the static load supporting the power unit is shared in the direction of the central shaft (outer central shaft 32) of the mount.

[0045] The fixing portion 18 of the inner component 12 and the outer cylinder component 14 are disposed separately from each other in the vertical direction. The fixing portion 18 of the inner component 12 and the outer cylinder component 14, which is disposed separately on the outer periphery of the inner component 12, are elastically connected by a main body rubber elastomer 16. The main body rubber elastomer 16 is generally frustoconical in shape with a large diameter facing downwards. The fixing portion 18 is embedded in the upper end of the smaller diameter side, and it is fixed in a state where the upper end face partially overlaps with the outer flange-like portion 20. In addition, the outer cylinder component 14 is overlapped and fixed to the surface of the lower end of the larger diameter side. In this embodiment, the main body rubber elastomer 16 is formed as an integral vulcanized molded product having the inner component 12 and the outer cylinder component 14.

[0046] The main body rubber elastomer 16 is provided with a recess 34 that opens on its lower surface. The recess 34 has a generally spherical inner surface that gradually increases in diameter downwards. The recess 34 is located closer to the inner circumference than the inner circumferential end of the inner flange-like portion 30 in the outer cylinder member 14. Therefore, in this embodiment, the recess 34 opens to the outside through the lower opening of the outer cylinder member 14.

[0047] like Figure 7 As shown, the recess 34 in this embodiment has a circular cross-section, and more particularly in this embodiment, the recess 34 has a perfectly circular cross-section. That is, in this embodiment, the center of the opening and the center of the bottom in the recess 34 are at... Figure 7 The recesses are located at the same positions in the cross-section shown. In summary, the recess 34 has a central axis extending in the vertical direction, and the center of the opening and the center of the bottom of the recess 34 are located on this central axis. Furthermore, the recess 34 has an inner surface that is formed as rotationally symmetric about the central axis.

[0048] In this embodiment, the central axis of the recess 34 is coaxial with the component central axis (outer central axis 32) of the outer cylinder component 14. As a result, the inner peripheral surface 36 of the main body rubber elastomer 16, which is formed by the inner surface of the recess 34, is formed into a perfect circle with the central axis (outer central axis 32) of the engine bracket 10 as the center in the cross section (cross section) perpendicular to the axis.

[0049] By providing the recess 34, the main body rubber elastomer 16 is substantially formed into a shape in which the rubber connecting the inner member 12 and the outer cylinder member 14 in the inclined direction is continuous throughout the entire circumference. The depth dimension (vertical dimension) of the recess 34 does not reach the fixing portion 18 of the inner member 12, which is fixed in a state of being embedded in the upper end of the main body rubber elastomer 16, and the lower end of the inner member 12 does not protrude from the recess 34. In summary, in the inner circumferential portion of the main body rubber elastomer 16 that connects the inner member 12 and the outer cylinder member 14 in the inclined direction, a continuous rubber 40 is provided that covers the lower end of the inner member 12, thereby making the main body rubber elastomer 16 continuous. This continuous rubber 40 extends in the direction perpendicular to the axis, connecting the inner circumferential portion of the main body rubber elastomer 16 in each direction perpendicular to the axis, including the front-back direction and the left-right direction. In this embodiment, the continuous rubber 40 is integrally formed with the main body rubber elastomer 16.

[0050] Here, in the engine bracket 10, the component center axis (inner center axis 22) of the inner component 12 is eccentric in the direction perpendicular to the axis relative to the component center axis (outer center axis 32) of the outer cylinder component 14. In this embodiment, as shown... Figure 2 , Figure 3 As shown, the inner central axis 22 and the outer central axis 32 are offset in the front-rear direction. In particular, in this embodiment, the inner central axis 22 is positioned further forward than the outer central axis 32.

[0051] Therefore, in the main rubber elastomer 16, the free lengths of the inner member 12 and the outer cylinder member 14 in the opposing directions are different in the circumferential direction. Specifically, as Figure 3 As indicated by the white arrow, on the front side, which is the eccentric direction, the free length Lf of the main rubber elastomer 16 extending from the inner member 12 toward the outer cylinder member 14 towards the front of the vehicle is shorter than the free length Lr of the main rubber elastomer 16 extending from the inner member 12 toward the outer cylinder member 14 towards the rear of the vehicle on the rear side, which is the other eccentric direction. Furthermore, in this specification, the free length of the main rubber elastomer 16 in the opposing direction between the inner member 12 and the outer cylinder member 14 refers to the length of the elastic center of the main rubber elastomer 16 in the opposing direction between the inner member 12 and the outer cylinder member 14.

[0052] Furthermore, as described above, the inner central axis 22 is eccentrically positioned at the front relative to the outer central axis 32, resulting in a circumferential difference in the surface length of the outer peripheral surface 42 of the main body rubber elastomer 16. That is, the surface length of the outer peripheral surface 42 of the main body rubber elastomer 16 differs on both sides in the eccentric direction (front-rear direction), with the rear portion being longer than the front portion. Additionally, in this specification, the surface length of the outer peripheral surface 42 of the main body rubber elastomer 16 refers to the length of the outer peripheral surface 42 in the circumferential direction. Figure 3 The length along the outer circumferential surface 42 in the longitudinal section shown.

[0053] Furthermore, in this embodiment, as... Figure 6 As shown, in the cross-section perpendicular to the axis, the outer peripheral surface 42 of the main rubber elastomer 16 is a perfect circle. That is, in the upper part of the main rubber elastomer 16, in the part fixed to the fixing portion 18 of the inner member 12, the center of the cross-section is located relatively close to the inner central axis 22. On the other hand, as it moves downward, the center of the cross-section gradually shifts backward. In the lower part of the main rubber elastomer 16, in the part fixed to the outer cylinder member 14, the center of the cross-section overlaps with the outer central axis 32.

[0054] In addition, in this embodiment, since the fixing part 18 has a circular cross-section, the inner fixing surface 44 that fixes the fixing part 18 to the upper part of the main rubber elastomer 16 also has a circular cross-section.

[0055] In the engine mount 10 of this embodiment, constructed as described above, as previously stated, the inner member 12 is fixed to the power unit by screwing a fixing bolt into the bolt hole 24 of the inner member 12. Furthermore, the outer member 14 is fixed to the vehicle body by fixing a subframe or the like, which is inserted into the outer member 14, to the vehicle body. Thus, the power unit and the vehicle body are elastically connected via the engine mount 10.

[0056] Furthermore, when the vehicle accelerates, a rearward load is input to the engine mount 10, causing the inner member 12 to move closer to the outer cylinder member 14 in the rear portion and to move further away from the outer cylinder member 14 in the front portion. Conversely, when the vehicle decelerates, a forward load is input to the engine mount 10, causing the inner member 12 to move closer to the outer cylinder member 14 in the front portion and to move further away from the outer cylinder member 14 in the rear portion. Thus, in the engine mount 10, loads in opposite directions (front and rear) are input in the direction perpendicular to the axis, depending on the vehicle's acceleration and deceleration.

[0057] When such loads are applied, especially during vehicle acceleration, a torque reaction force is applied in addition to the acceleration G, making it a larger load compared to deceleration. Therefore, it is observed that the rear portion of the main rubber elastomer is compressed between the rearwardly displaced inner and outer cylinder members, deforming circumferentially towards both sides of the inner member. The inner circumferential portion of the main rubber elastomer, fixed to the inner member, is prone to large deformation and stress in the shear direction, which is why durability is difficult to ensure in existing engine mount structures.

[0058] Based on this understanding, in the engine mount 10 of this embodiment, the inner central shaft 22 is eccentric relative to the outer central shaft 32 in the longitudinal direction, and the free length Lr of the rear portion of the main rubber elastomer 16 is increased relative to the free length Lf of the front portion. As a result, when the vehicle accelerates, even if the rear portion of the main rubber elastomer 16 is compressed due to a relatively large input load, deformation under load can be suppressed, and compression deformation of the rear portion and shear deformation caused by deformation such as wrapping around the inner member 12 in the circumferential direction can be reduced. Therefore, even if the radial side sandwiching the inner member 12 is subjected to a much larger load than the other side, unnecessary thickening of the main rubber elastomer 16 or the resulting reduction in vibration damping characteristics can be avoided, and the durability of the main rubber elastomer 16 can be effectively ensured.

[0059] On the other hand, when the vehicle decelerates, a relatively small load is applied to the front portion of the main rubber elastomer 16. However, since the free length Lf of the front portion of the main rubber elastomer 16 is reduced, it is possible to avoid the front portion of the main rubber elastomer 16 becoming unnecessarily longer. As a result, it is also possible to avoid the enlargement of the main rubber elastomer 16, the outer cylinder member 14, and consequently the engine mount 10.

[0060] In addition, in this embodiment, a continuous rubber 40 is provided to make the inner circumferential portion of the main rubber elastomer 16 continuous. Therefore, during vehicle acceleration, the deformation and stress caused by the load input to the rear portion of the main rubber elastomer 16 are also transmitted to the front and left / right portions of the main rubber elastomer 16 via the continuous rubber 40. This also prevents the deformation and stress caused by the main rubber elastomer 16 from becoming excessive on one side, thereby further improving the durability of the main rubber elastomer 16 and, consequently, the engine mount 10.

[0061] Furthermore, in this embodiment, the outer peripheral surface 42 and the inner peripheral surface 36 of the main rubber elastomer 16 are both circular in cross-section perpendicular to the axis. Therefore, when a load is input, the deformation of the main rubber elastomer 16 can be generated smoothly, and local concentration of deformation and stress can be avoided more effectively. As a result, the durability of the main rubber elastomer 16 can be improved more stably.

[0062] Furthermore, in this embodiment, the surface lengths of the inner central axis 22 on both sides of the outer peripheral surface 42 of the main rubber elastomer 16 in the eccentric direction (front-back direction) relative to the outer central axis 32 are different from each other. In this way, by making the surface lengths of the outer peripheral surface 42 of the main rubber elastomer 16 different in the eccentric direction (front-back direction), the free length on both sides of the main rubber elastomer 16 in the front-back direction can be appropriately set, and the aforementioned durability improvement effect can be achieved more stably.

[0063] The embodiments of the present invention have been described in detail above, but the present invention is not limited to its specific description.

[0064] For example, in the above embodiment, the eccentricity direction of the component center axis (inner center axis 22) of the inner component 12 relative to the component center axis (outer center axis 32) of the outer cylinder component 14 is the front-rear direction, but it is not limited to this method. That is, in the present invention, it is possible to input loads of different magnitudes in opposite directions along one of the directions orthogonal to the center axis of the vibration damping component, as long as the component center axis of the inner component is eccentric relative to the component center axis of the outer cylinder component in a direction that matches the direction of the loads input at different magnitudes.

[0065] Furthermore, in the above embodiment, the continuous rubber 40 makes the inner circumferential portion of the main body rubber elastomer 16 continuous in each direction perpendicular to the axis. However, the continuous rubber only needs to make the main body rubber elastomer on one side continuous with the main body rubber elastomer on the other side in the eccentric direction of the component center axis of the inner component relative to the component center axis of the outer cylinder component. In the case of the above embodiment, it is sufficient to make the main body rubber elastomer 16 on the front side continuous with the main body rubber elastomer 16 on the rear side.

[0066] Furthermore, in the cross-section perpendicular to the axis, the shape of the outer and inner circumferential surfaces of the main rubber elastomer is not limited, but a circular shape including ellipses, oblongs, etc. is preferred, and a perfect circle shape as described in the above embodiment is more preferred. In addition, the shape of the inner component and the outer cylinder component is not limited, and the shape of the fixing part of the inner component and the shape of the outer cylinder component perpendicular to the axis can also be a circular shape including ellipses, oblongs, etc., or a polygon.

[0067] Furthermore, in the above embodiment, in a cross-section perpendicular to the axis, the inner circumferential surface 36 of the main rubber elastomer 16 is a perfect circle. That is, in a cross-section perpendicular to the axis, the position of the opening center of the recess 34 is the same as the position of the bottom center. On both sides of the eccentric direction (front-back direction) of the component center axis (inner center axis 22) of the inner component 12 relative to the component center axis (outer center axis 32) of the outer cylinder component 14, the surface length from the bottom center of the recess 34 to the opening end (in... Figure 3 The lengths along the inner surface of the recess 34 in the longitudinal section shown are equal, but not limited to this manner. For example, in a section perpendicular to the axis, the bottom center of the recess is offset relative to the opening center of the recess in an eccentric direction relative to the component center axis of the inner member relative to the component center axis of the outer cylinder member, and the surface lengths from the bottom center of the recess to the opening end of the inner circumferential surface of the main rubber elastomer are different on both sides of the eccentric direction.

[0068] Alternatively, a combination of methods can be used, where the surface lengths of the outer circumferential surface of the main rubber elastomer are different on both sides of the eccentric direction relative to the central axis of the inner component and the surface lengths of the inner circumferential surface are different. Alternatively, the surface lengths of the outer and inner circumferential surfaces can be increased on one side of the eccentric direction (and decreased on the other side), or the surface lengths of the outer circumferential surface can be increased on one side of the eccentric direction and the surface lengths of the inner circumferential surface can be decreased (and the surface lengths of the outer and inner circumferential surfaces can be decreased on the other side of the eccentric direction).

[0069] Furthermore, in the above embodiment, the inner member 12 is provided with a pin-shaped protrusion 28 serving as a circumferential positioning portion, and the lower end of the inner member 12 is covered by a continuous rubber 40 integrally formed with the main body rubber elastomer 16. However, when the circumferential positioning portion is provided to define the longitudinal direction of the vehicle, the continuous rubber may not be provided, and the lower end of the inner member may protrude from the inner surface of the recess. Alternatively, when the continuous rubber is provided, the circumferential positioning portion may not be provided.

[0070] Furthermore, the circumferential positioning part is not limited to the pin-shaped protrusion 28 of the above embodiment. That is, as long as the circumferential positioning part can be used to define the front-rear direction of the vehicle, it can be a protrusion that protrudes outward as in the above embodiment, or it can be a recess, or it can be a piece of paper that shows the predetermined direction, or it can be engraved to define the front-rear direction. In addition, the circumferential positioning part can replace the inner component, or it can be provided on the outer cylinder component or the main body rubber elastomer.

[0071] Furthermore, in the above embodiment, the inner mounting shaft 26, which serves as the mounting center shaft of the inner member 12, and the outer mounting shaft (outer center shaft 32), which serves as the mounting center shaft of the outer cylinder member 14, are coaxial in either the state before or during the assembly of the engine mount 10 to the vehicle. However, the two mounting shafts may also be offset from each other in at least one of the states before or during the assembly of the vibration damping device to the vehicle. That is, for example, if the mounting center shaft of the inner member and the mounting center shaft of the outer cylinder member are offset from each other before assembly to the vehicle, the offset can be taken into account when setting the eccentricity of the component center shaft of the inner member relative to the component center shaft of the outer cylinder member. In addition, for example, if the mounting center shaft of the inner member and the mounting center shaft of the outer cylinder member are offset by assembling the vibration damping device to the vehicle, the offset can be taken into account when setting the eccentricity of the component center shaft of the inner member relative to the component center shaft of the outer cylinder member.

[0072] Furthermore, in the above embodiments, an engine mount 10 for automobiles was exemplified as the vibration damping device according to the present invention. However, as the vibration damping device of the present invention, any vibration damping device that inputs different loads in opposite directions along one of the directions orthogonal to the central axis can be used. For example, a torque bracket that inputs different loads on the drive side and the opposite drive side can also be used. In addition, in the above embodiments, the vibration damping device (engine mount 10) is a so-called solid type vibration damping device that exerts a vibration damping effect with the deformation of rubber. However, the vibration damping device according to the present invention can also be a fluid-sealed vibration damping device that has a fluid chamber filled with an incompressible fluid inside and utilizes a vibration damping effect based on fluid flow.

[0073] [Explanation of Labels in the Attached Image]

[0074] 10: Engine mount;

[0075] 12: Internal components;

[0076] 14: Outer cylinder components;

[0077] 16: Main body rubber elastomer;

[0078] 18: Fixed part;

[0079] 20: Outer convex margin;

[0080] 22: Inner central axis;

[0081] 24: Bolt hole;

[0082] 26: Internal mounting shaft;

[0083] 28: Pin-shaped protrusion;

[0084] 30: Inner convex margin;

[0085] 32: Outer central axis;

[0086] 33: External fixing surface;

[0087] 34: concave part;

[0088] 36: Inner circumferential surface;

[0089] 40: Continuous rubber;

[0090] 42: Outer peripheral surface;

[0091] 44: Internal fastening surface.

Claims

1. A vibration damping device, wherein an inner component (12) and an outer cylinder component (14) separately disposed on the outer periphery of the inner component (12) are connected by a main rubber elastomer (16), wherein, The main rubber elastomer (16) is truncated cone-shaped and has a recess (34) with an opening on the lower surface. The central axis of the fixing part (18) in the inner component (12) for fixing the main rubber elastomer (16) is eccentric relative to the central axis of the outer cylinder component (14) in a direction perpendicular to the axis. The free lengths of the main rubber elastomer (16) on one side of the eccentric direction in the opposing direction between the inner member (12) and the outer cylinder member (14), and the free lengths of the main rubber elastomer (16) on the other side of the eccentric direction in the opposing direction between the inner member (12) and the outer cylinder member (14) are different from each other, and The lower end of the inner member (12) does not protrude from the recess (34), and covers the lower end of the inner member (12) so that the continuous rubber (40) of the main rubber elastomer (16) on one side of the eccentric direction and the main rubber elastomer (16) on the other side of the eccentric direction is integrally formed with the main rubber elastomer (16).

2. The vibration damping device according to claim 1, wherein, The mounting center axis of the inner component (12) is coaxial with the mounting center axis of the outer cylinder component (14).

3. A vibration damping device, wherein an inner component (12) and an outer cylinder component (14) separately disposed on the outer periphery of the inner component (12) are connected by a main rubber elastomer (16), wherein, The main rubber elastomer (16) is truncated cone-shaped and has a recess (34) with an opening on the lower surface. The vibration damping device is provided with a circumferential positioning part. This circumferential positioning part, in the assembled state where the central axis of the vibration damping device is set to the vertical direction of the vehicle, is used to position the vibration damping device circumferentially. This circumferential positioning part defines the longitudinal direction of the vehicle. The central axis of the fixing part (18) in the inner component (12) for fixing the main rubber elastomer (16) is eccentrically arranged relative to the central axis of the outer cylinder component (14) in the longitudinal direction of the vehicle. The free length of the main rubber elastomer (16) extending forward from the inner component (12) toward the outer cylinder component (14) and the free length of the main rubber elastomer (16) extending backward from the vehicle are different from each other. When the vehicle accelerates, the free length of the main rubber elastomer (16) in the inner component (12) that is closer to the displacement relative to the outer cylinder component (14) is greater than the free length of the main rubber elastomer (16) that is separated from the displacement.

4. The vibration damping device according to claim 3, wherein, In either the pre-assembly or assembly state of the vehicle, the mounting center axis of the inner component (12) and the mounting center axis of the outer cylinder component (14) are coaxial.

5. The vibration damping device according to any one of claims 1 to 4, wherein, In a cross section perpendicular to the axis, the outer and inner circumferential surfaces of the main rubber elastomer (16) are both circular.

6. The vibration damping device according to any one of claims 1 to 4, wherein, In at least one of the outer peripheral surface (42) and the inner peripheral surface (36) of the main body rubber elastomer (16), the surface lengths of the two sides of the component central axis of the inner component (12) relative to the component central axis of the outer cylinder component (14) are different from each other.

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