JP2021063548A - Vehicular vibration isolating device - Google Patents

Abstract

To provide a vehicular vibration isolating device capable of sufficiently attenuating vibrations in a wide frequency zone.SOLUTION: A vehicular vibration isolating device 1 is equipped with a first attaching member 5 to be attached to a first member 2, a second attaching member 6 to be attached to a second member 3, a first liquid chamber 10 and a second liquid chamber 11 that change capacities according to the relative displacement of the first attaching member 5 and the second attaching member 6, and an orifice passage 12 circulating liquid M between the first liquid chamber 10 and the second liquid chamber 11 according to the change of the capacities of the first liquid chamber 10 and the second liquid chamber 11. The liquid M includes a non-Newtonian fluid whose viscosity lowers according to a rise of shear velocity. Particles P having different density from the non-Newtonian fluid are added to the liquid M.SELECTED DRAWING: Figure 1

Description

The present invention relates to a vehicle vibration isolator.

A vehicle vibration isolator that damps vibration by circulating a liquid between a plurality of liquid chambers via an orifice passage is known (for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2004-324823

In such a vehicle vibration isolator, the required liquid viscosity differs depending on the frequency range in which vibration occurs. For example, in the frequency region where the amount of vibration damping is maximum, it is required to reduce the viscosity of the liquid in order to sufficiently dampen the vibration by utilizing the so-called liquid column resonance phenomenon. On the other hand, in a frequency region lower than the above frequency region, it is required to increase the viscosity of the liquid in order to sufficiently attenuate the vibration by utilizing the so-called viscous damping.

In order to meet such various demands on the viscosity of the liquid, it is desirable to increase the amount of change in the viscosity of the liquid. However, the conventional anti-vibration device for vehicles has not been devised to increase the amount of change in the viscosity of the liquid. Therefore, there is a possibility that the vibration cannot be sufficiently attenuated in a wide frequency range.

In view of the above background, it is an object of the present invention to provide a vehicle vibration isolator that sufficiently attenuates vibration in a wide frequency range.

In order to solve the above problems, one aspect of the present invention is a vehicle vibration isolator (1), which is a first mounting member (5) to be mounted on the first member (2) and a second member (3). The second liquid chamber (6) to be attached to the first liquid chamber (10) and the second liquid chamber (11) whose volume is changed according to the relative displacement between the first mounting member and the second mounting member. The liquid is provided with an orifice passage (12) for flowing a liquid (M) between the first liquid chamber and the second liquid chamber according to a change in the volume of the first liquid chamber and the second liquid chamber. However, it contains a non-Newtonian fluid whose viscosity decreases as the shear rate increases, and particles (P) having a density different from that of the non-Newtonian fluid are added to the liquid.

According to this aspect, when the liquid flows between the first liquid chamber and the second liquid chamber through the orifice passage, the liquid can be agitated by the particles added to the liquid. As a result, the liquid can be turbulent and the shear rate of the liquid can be increased. Therefore, the viscosity of the liquid can be sufficiently lowered and the amount of change in the viscosity of the liquid can be increased. This makes it possible to sufficiently attenuate the vibration in a wide frequency range.

In the above embodiment, the density of the particles may be higher than the density of the non-Newtonian fluid.

According to this aspect, when the liquid flows between the first liquid chamber and the second liquid chamber, the particles move behind the liquid, and it becomes easy to increase the shear rate of the liquid at the interface of the particles. Therefore, the viscosity of the liquid can be further reduced, and the amount of change in the viscosity of the liquid can be further increased.

In the above embodiment, the particles may be glass beads.

According to this aspect, the particles can be easily spheroidized and the particles having a small diameter can be easily produced.

In the above aspect, the particles may be resin beads.

According to this aspect, the particles can be easily spheroidized and the particles having a small diameter can be easily produced.

In the above aspect, the particles may be metal spheres.

According to this aspect, the density of particles can be sufficiently increased with respect to the density of non-Newtonian fluids. Therefore, the particles can sufficiently agitate the liquid and promote turbulence of the liquid.

In the above aspect, the maximum diameter of the particles may be 5 μm or more and 1 mm or less.

According to this aspect, the stirring action of the liquid by the particles can be sufficiently enhanced while suppressing the clogging of the orifice passage by the particles.

In the above aspect, the vehicle vibration isolator includes the elastically deformable first wall body (7) that partially defines the first liquid chamber and supports the first mounting member, and the second liquid. The first wall body (8), which partially defines the chamber and is elastically deformable to be attached to the second mounting member, and the first liquid chamber to partition the second liquid chamber from the first liquid chamber. It may have a partition wall (9) which is coupled to the wall body and is provided with the orifice passage.

According to this aspect, the vibration damping action of the vehicle vibration isolator can be enhanced.

In the above embodiment, the non-Newtonian fluid may be a thixotropic fluid.

According to this aspect, the viscosity of the non-Newtonian fluid can be gradually reduced as the shear rate increases. Therefore, it is possible to suppress a sudden change in the vibration damping characteristics of the vehicle vibration isolator.

According to the above configuration, it is possible to provide a vehicle vibration isolator that sufficiently attenuates vibration in a wide frequency range.

Sectional drawing of the engine mount which concerns on one Embodiment of this invention Graph showing viscosity characteristics of Newtonian fluid and thixotropic fluid

Hereinafter, a liquid-filled engine mount 1 (an example of a vehicle vibration isolator) according to an embodiment of the present invention will be described with reference to the drawings. Arrows U and Lo appropriately attached to each figure indicate the upper side and the lower side of the engine mount 1, respectively.

<Configuration of engine mount 1>
With reference to FIG. 1, the engine mount 1 is arranged between an engine 2 (an example of a first member) and a vehicle body 3 (an example of a second member), which are internal combustion engines, in a vehicle such as an automobile. The engine mount 1 is a component for supporting the engine 2 while suppressing the vibration of the engine 2.

The engine mount 1 is a first wall body arranged between a first mounting member 5 mounted on the engine 2, a second mounting member 6 mounted on the vehicle body 3, and a first mounting member 5 and a second mounting member 6. 7, a second wall body 8 arranged below the first wall body 7, a partition wall 9 arranged between the first wall body 7 and the second wall body 8, and a first wall body 9 provided above the partition wall 9. It includes a 1-liquid chamber 10, a second liquid chamber 11 provided below the partition wall 9, and an orifice passage 12 provided on the outer periphery of the partition wall 9. Hereinafter, the components of the engine mount 1 will be described in order.

The first mounting member 5 of the engine mount 1 is located at the upper end of the engine mount 1. The first mounting member 5 includes an engaging portion 14 and a mounting portion 15 projecting upward from the upper surface of the engaging portion 14. The mounting portion 15 is mounted on the engine 2 by bolts 16.

The second mounting member 6 of the engine mount 1 is located below the engine mount 1. The second mounting member 6 includes an outer cylinder portion 18 and an inner cylinder portion 19 arranged on the inner peripheral side of the outer cylinder portion 18. The upper end of the outer cylinder 18 and the upper end of the inner cylinder 19 are attached to each other by bolts 20. The lower portion of the outer cylinder portion 18 is attached to the vehicle body 3 by bolts (not shown).

The first wall body 7 of the engine mount 1 is made of rubber and is provided so as to be elastically deformable. An upper concave portion 22 opened upward is provided on the upper portion of the first wall body 7. The engaging portion 14 of the first mounting member 5 is engaged with the upper recess 22. As a result, the first wall body 7 supports the first mounting member 5 from below. A lower concave portion 23 opened downward is provided in the lower portion of the first wall body 7.

The second wall 8 of the engine mount 1 is a so-called diaphragm. The second wall body 8 is formed of rubber and is provided so as to be elastically deformable. The outer peripheral portion of the second wall body 8 is engaged with the lower inner circumference of the inner cylinder portion 19 of the second mounting member 6. As a result, the second wall body 8 is attached to the second attachment member 6.

The partition wall 9 of the engine mount 1 partitions the second liquid chamber 11 with respect to the first liquid chamber 10. The partition wall 9 includes a cylindrical peripheral wall portion 25 and a bottom wall portion 26 that covers the lower end portion of the peripheral wall portion 25. The peripheral wall portion 25 is engaged with the lower recess 23 of the first wall body 7. As a result, the partition wall 9 is connected to the first wall body 7. A spiral outer peripheral groove 27 is provided on the outer peripheral surface of the peripheral wall portion 25.

The first liquid chamber 10 of the engine mount 1 is a space defined by the lower recess 23 and the partition wall 9 of the first wall body 7. That is, the first liquid chamber 10 is a space partially defined by the first wall body 7. The first liquid chamber 10 contains a mount liquid M (an example of a liquid).

The second liquid chamber 11 of the engine mount 1 is provided below the first liquid chamber 10. The second liquid chamber 11 is a space defined by the second wall body 8 and the partition wall 9. That is, the second liquid chamber 11 is a space partially defined by the second wall body 8. The second liquid chamber 11 contains the mount liquid M.

The orifice passage 12 of the engine mount 1 is a passage defined by an outer peripheral groove 27 provided on the outer peripheral surface of the peripheral wall portion 25 of the partition wall 9 and a lower recess 23 of the first wall body 7. That is, the orifice passage 12 is a passage partially defined by the outer peripheral groove 27. The orifice passage 12 is curved in an arc shape in the axial direction (longitudinal direction) thereof. The first end of the orifice passage 12 communicates with the first liquid chamber 10, and the second end of the orifice passage 12 communicates with the second liquid chamber 11. That is, the orifice passage 12 communicates the first liquid chamber 10 and the second liquid chamber 11 with each other.

<Action of engine mount 1>
When the engine 2 vibrates, the first wall body 7 and the second wall body 8 are elastically deformed in response to the relative displacement of the first mounting member 5 and the second mounting member 6, and the first liquid chamber 10 and the second The volume of the liquid chamber 11 changes. For example, when the first mounting member 5 descends with respect to the second mounting member 6, the first wall body 7 and the second wall body 8 are elastically deformed downward, the volume of the first liquid chamber 10 is reduced, and the second wall body 8 is second. The volume of the liquid chamber 11 increases. On the other hand, when the second mounting member 6 rises with respect to the first mounting member 5, the first wall body 7 and the second wall body 8 are elastically deformed upward, the volume of the first liquid chamber 10 increases, and the volume of the first liquid chamber 10 increases. 2 The volume of the liquid chamber 11 is reduced.

As the volumes of the first liquid chamber 10 and the second liquid chamber 11 change in this way, the mount liquid M flows between the first liquid chamber 10 and the second liquid chamber 11 via the orifice passage 12. .. For example, when the volume of the first liquid chamber 10 decreases and the volume of the second liquid chamber 11 increases, the mount liquid M flows from the first liquid chamber 10 into the second liquid chamber 11. On the other hand, when the volume of the first liquid chamber 10 increases and the volume of the second liquid chamber 11 decreases, the mount liquid M flows from the second liquid chamber 11 into the first liquid chamber 10. As the mount liquid M flows between the first liquid chamber 10 and the second liquid chamber 11 through the orifice passage 12 in this way, the vibration of the engine 2 is damped.

<Mount liquid M>
The mount liquid M is composed only of non-Newtonian fluid. In another different embodiment, the mount liquid M may be composed of both a non-Newtonian fluid and a Newtonian fluid.

The non-Newtonian fluid constituting the mount liquid M is a thixotropic fluid (hereinafter, abbreviated as “thixotropy”). With reference to FIG. 2, the viscosity of the Newtonian fluid is constant regardless of the shear rate, whereas the viscosity of the thixotropy gradually decreases as the shear rate increases. In another different embodiment, a fluid other than thixotropy (for example, Bingham fluid) may be used as the non-Newtonian fluid constituting the mount liquid M.

The thixofluid constituting the mount liquid M is formed by mixing a thixotropy-imparting agent (hereinafter, abbreviated as “thixotropy”) with the base liquid composed of the Newtonian fluid. In another different embodiment, the thixotropy fluid constituting the mount liquid M may contain additives other than the base liquid and the thixotropy.

The base liquid of thixofluid is formed by dissolving a glycol-based solvent (for example, ethylene glycol or propylene glycol) in water. Ethylene glycol has an effect of lowering the freezing temperature of water and has a low viscosity among solvents having such an effect, and is therefore preferable as a solvent for the base liquid. In another different embodiment, the base liquid may be formed by dissolving a solvent other than the glycol-based solvent in water. Further, in other different embodiments, the base liquid may be formed by dissolving a solvent in a liquid other than an aqueous liquid (for example, an oil-based liquid).

The thixotropy of thixofluid is composed of an inorganic material (eg, bentonite or silica). Montmorillonite contained in bentonite is preferable as a thixotropy because it has an effect of reducing the temperature dependence of the characteristics of thixofluid. In other different embodiments, the thixotropy may be composed of an organic material (eg, a cellulose derivative or a polyether material) or a composite material (eg, organic bentonite or calcium carbonate). It may have been done. If the content of the thixotropic agent in the thixotropy fluid is 10 wt% or less, the thixotropic agent can be uniformly dispersed throughout the thixotropy fluid. However, the content of the thixotropic agent in the thixotropy fluid may be an amount exceeding 10 wt% (for example, 20 wt%).

With reference to FIG. 1, particles P having a density different from that of the thixotropy fluid are added to the mount liquid M. Particle P is a solid particle. The density of the particles P is higher than the density of the thixotropic fluid. In other different embodiments, the density of the particles P may be lower than the density of the thixotropic fluid.

The particles P are composed of, for example, glass beads, resin beads or metal spheres. Since the particles P are composed of glass beads or resin beads, the particles P can be easily spheroidized, and the particles P having a small diameter can be easily produced. On the other hand, since the particles P are composed of metal spheres, the density of the particles P can be sufficiently increased with respect to the density of the thixotropy fluid. Therefore, the mount liquid M can be sufficiently agitated by the particles P to promote turbulence of the mount liquid M. In other different embodiments, a material other than glass beads, resin beads, or metal spheres may be used as the particles P.

The maximum diameter of the particle P is set in a practical range in consideration of the diameter of the orifice passage 12. The maximum diameter of the particles P is 5 μm or more and 1 mm or less. By setting the maximum diameter of the particles P to 5 μm or more, the stirring action of the mount liquid M by the particles P can be sufficiently enhanced. By setting the maximum diameter of the particles P to 1 mm or less, clogging of the orifice passage 12 due to the particles P can be suppressed. In other different embodiments, the maximum diameter of the particles P may be less than 5 μm or more than 1 mm.

<Effect>
As described above, in the present embodiment, particles P having a density different from that of the thixotropy fluid are added to the mount liquid M. Therefore, when the mount liquid M flows between the first liquid chamber 10 and the second liquid chamber 11 through the orifice passage 12, a phase shift occurs between the amplitude of the mount liquid M and the amplitude of the particles P due to the inertial force. The mount liquid M can be agitated by the particles P. As a result, the mount liquid M can be turbulent and the shear rate of the thixotropy fluid constituting the mount liquid M can be increased. Therefore, the viscosity of the thixotropy fluid can be sufficiently reduced and the amount of change in the viscosity of the thixotropy fluid can be increased as compared with the case where the particles P are not added to the mount liquid M (see FIG. 2). As a result, in the frequency region where the amount of vibration damping is maximum, the viscosity of the mount liquid M can be sufficiently reduced, and the vibration can be sufficiently damped by utilizing the so-called liquid column resonance phenomenon. On the other hand, in a frequency region lower than the above frequency region, the viscosity of the mount liquid M can be sufficiently increased, and vibration can be sufficiently attenuated by utilizing so-called viscous damping. That is, the vibration can be sufficiently attenuated in a wide frequency range. As the flow velocity of the mount liquid M increases, the degree of turbulence of the mount liquid M increases.

Further, by adding the particles P to the mounting liquid M, the vibration can be sufficiently attenuated in a wide frequency range without changing the configuration of the orifice passage 12. Therefore, it is possible to suppress an increase in the manufacturing cost of the engine mount 1, and it is also possible to cope with a case where the inner diameter of the orifice passage 12 is too small and it is physically difficult to change the configuration of the orifice passage 12.

Also, the density of the particles P is higher than the density of the thixotropy fluid. Therefore, when the mount liquid M flows between the first liquid chamber 10 and the second liquid chamber 11, the particles P move behind the mount liquid M, and the shear rate of the mount liquid M at the interface of the particles P. It becomes easy to raise. Therefore, the viscosity of the mount liquid M can be further reduced, and the amount of change in the viscosity of the mount liquid M can be further increased.

Further, the engine mount 1 partially defines the first liquid chamber 10 and partially defines the elastically deformable first wall body 7 that supports the first mounting member 5 and the second liquid chamber 11. In addition, the elastically deformable second wall body 8 attached to the second mounting member 6 and the second liquid chamber 11 are coupled to the first wall body 7 in order to partition the first liquid chamber 10 from the first liquid chamber 10, and the orifice passage 12 Has a partition wall 9 provided with. Therefore, the vibration damping action of the engine mount 1 can be enhanced.

Further, since the non-Newtonian fluid constituting the mount liquid M is a thixotropy, the viscosity of the non-Newtonian fluid can be gradually reduced as the shear rate increases. Therefore, it is possible to suppress a sudden change in the vibration damping characteristic of the engine mount 1.

<Modification example>
In the above embodiment, the orifice passage 12 is curved in an arc shape in the axial direction thereof. On the other hand, in other different embodiments, the orifice passage 12 may extend linearly in its axial direction.

In the above embodiment, the engine mount 1 that supports the engine 2 is used as an example of the vehicle vibration isolator. On the other hand, in other different embodiments, the motor mount that supports the motor may be used as an example of the vehicle vibration isolator, and the shock absorber used for the suspension may be used as an example of the vehicle vibration isolator. That is, the vehicle vibration isolator according to the present invention can be applied to any place in the vehicle where vibration damping is required.

Although the description of the specific embodiment is completed above, the present invention is not limited to the above-described embodiment and modification, and can be widely modified.

1: Engine mount (an example of vehicle vibration isolation device)
2: Engine (an example of the first member)
3: Body (an example of the second member)
5: 1st mounting member 6: 2nd mounting member 7: 1st wall body 8: 2nd wall body 9: Partition wall 10: 1st liquid chamber 11: 2nd liquid chamber 12: Orifice passage M: Mount liquid (of liquid) One case)
P: Particles

Claims (8)

The first mounting member to be attached to the first member,
The second mounting member to be attached to the second member,
A first liquid chamber and a second liquid chamber whose volume is changed according to the relative displacement of the first mounting member and the second mounting member.
A vehicle vibration isolator provided with an orifice passage for flowing a liquid between the first liquid chamber and the second liquid chamber according to a change in the volume of the first liquid chamber and the second liquid chamber. ,
The liquid comprises a non-Newtonian fluid whose viscosity decreases with increasing shear rate.
A vehicle vibration isolator characterized in that particles having a density different from that of the non-Newtonian fluid are added to the liquid. The vehicle vibration isolator according to claim 1, wherein the density of the particles is higher than the density of the non-Newtonian fluid. The vehicle vibration isolator according to claim 2, wherein the particles are glass beads. The vehicle vibration isolator according to claim 2, wherein the particles are resin beads. The vehicle vibration isolator according to claim 2, wherein the particles are metal spheres. The vehicle vibration isolator according to any one of claims 1 to 5, wherein the maximum diameter of the particles is 5 μm or more and 1 mm or less. An elastically deformable first wall body that partially defines the first liquid chamber and supports the first mounting member.
An elastically deformable second wall body that partially defines the second liquid chamber and is attached to the second mounting member.
Any one of claims 1 to 6, wherein the second liquid chamber is coupled to the first wall body so as to partition the first liquid chamber, and has a partition wall provided with the orifice passage. The vehicle anti-vibration device described in the section. The vehicle vibration isolator according to any one of claims 1 to 7, wherein the non-Newtonian fluid is a thixotropic fluid.

Images