Vibration damping device for vehicle

Abstract

Proposed is a rubber bush type vibration damping device for a vehicle, which solves the problem of vibration increase which may occur in the natural frequency of the vibration damping device by changing the shapes of an inner coupling part or an outer coupling part and by using difference in the lengths of rubber insulators due to the changing of the shapes thereof. The vibration damping device includes an inner coupling part, an outer coupling part, and a plurality of rubber insulators having have different natural frequency.

Claims

1. A vibration damping device for a vehicle for reducing a resonance energy caused by vibration of an engine or a motor of the vehicle, the vibration damping device comprising: an inner coupling part; an outer coupling part having a shape of surrounding the inner coupling part; and a plurality of rubber insulators having inner sides bonded to the inner coupling part and having outer sides bonded to the outer coupling part, so that each of the rubber insulators, with a portion of the inner coupling part to which the rubber insulator is bonded and a portion of the outer coupling part to which the rubber insulator is bonded, constitutes a plurality of unit vibration damping modules, wherein a shortest length of the plurality of unit vibration damping modules are defined as a shortest length from a portion of the rubber insulator bonded to the inner coupling part to a portion of the rubber insulator bonded to the outer coupling part, wherein the plurality of unit vibration damping modules have different shapes and different shortest lengths, wherein the plurality of the rubber insulators is made of the same materials, wherein a primary natural frequency of each of the plurality of rubber insulators is within 400 Hz to 3000 Hz and when a frequency of the vibration of the engine or the motor of the vehicle matches, the resonance energy occurs, wherein the shortest length of any one unit vibration damping module is 70% to 98% of the shortest length of any other unit vibration damping module.

2. The vibration damping device of claim 1, wherein the difference between a primary natural frequency of one rubber insulator and a primary natural frequency of another rubber insulator is within 40 Hz to 1000 Hz.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The above and other objectives, features, and other advantages of the present disclosure will be more clearly understood from the following detailed description when taken in conjunction with the accompanying drawings, in which:

(2) FIG. 1 is a cross-sectional view of a whole bush-type rubber bushing according to a conventional technology;

(3) FIGS. 2 to 4 are cross-sectional views of rubber bushings according to the conventional technology;

(4) FIG. 5 is a front view of a vibration damping device for a vehicle having a plurality of rubber insulators according to an embodiment of the present disclosure;

(5) FIG. 6 is a cross-sectional view taken along line A-A of FIG. 5;

(6) FIG. 7 is a sectional view taken along line B-B of FIG. 6;

(7) FIG. 8 is a front view of an inner coupling part of FIG. 5; and

(8) FIG. 9 is a graph illustrating difference between a resonance energy according to the embodiment of the present disclosure and a resonance energy according to the conventional technology.

DETAILED DESCRIPTION OF THE INVENTION

(9) Hereinafter, the exemplary embodiment of the present disclosure will be described in detail with reference to the accompanying drawings so that those skilled in the art to which the present disclosure belongs can easily embody the present disclosure. However, the present disclosure may be embodied in various different forms and is not limited to the embodiment described herein. In addition, in the drawings, parts irrelevant to the description of the present disclosure are omitted in order to clearly describe the present disclosure, and similar reference numerals are assigned to similar parts throughout the specification.

(10) Throughout the specification, when a part “includes” a certain component, it means that other components may be further included rather than excluding the other components unless specifically stated to the contrary.

(11) FIG. 5 is a front view of a vibration damping device for a vehicle having a plurality of rubber insulators according to an embodiment of the present disclosure; FIG. 6 is a cross-sectional view taken along line A-A of FIG. 5; FIG. 7 is a sectional view taken along line B-B of FIG. 6; FIG. 8 is a front view of an inner coupling part of FIG. 5; and FIG. 9 is a graph illustrating difference between a resonance energy according to the embodiment of the present disclosure and a resonance energy according to the conventional technology.

(12) The vibration damping device 100 for a vehicle is configured by including: the inner coupling part 110; an outer coupling part 120 having the shape of surrounding the inner coupling part 110; and each of the plurality of rubber insulators 130 having an inner side bonded to the inner coupling part 110 and having an outer side bonded to the outer coupling part 120.

(13) The inner coupling part 110 and the outer coupling part 120 are made of metal or hard plastic, and are intended to be coupled to other components of a vehicle.

(14) Each of the rubber insulators 130 is made of rubber for reducing vibration between the inner coupling part 110 and the outer coupling part 120.

(15) In the vibration damping device 100 for a vehicle, rubber materials are bonded to the inner coupling part 110 and to the outer coupling part 120, and some of the rubber materials constitute the rubber insulator 130. Except for the rubber materials constituting the rubber insulator 130, remaining rubber materials are provided to increase the bonding force of the rubber insulator 130 to the inner coupling part 110 or the outer coupling part 120.

(16) Accordingly, each of the rubber insulators 130 is made of the same material.

(17) Each of the rubber insulators 130 and portions of the inner coupling part and the outer coupling part to which each of the rubber insulators 130 is bonded constitute a unit vibration damping module.

(18) In the embodiment, four rubber insulators 130 separated from each other are provided, and further, four unit vibration damping modules are provided.

(19) The primary natural frequency of each of the rubber insulators 130 is preferably within 400 Hz to 3000 Hz.

(20) The primary natural frequency of such a rubber insulator 130 allows the rubber insulator 130 to have a basic static stiffness suitable for the rubber bushing. The vibration damping device for a vehicle having the rubber insulators 130 functions to reduce vibration in the entire range of the vehicle, and is particularly effective in attenuating resonance in the rubber insulator having the natural frequency of 400 Hz to 3000 Hz, which is a practical problem.

(21) In the embodiment, the shortest length of the unit vibration damping module (or the shortest length of the rubber insulator) is defined as the shortest length from a portion of the rubber insulator 130 bonded to the inner coupling part 110 to a portion of the rubber insulator 130 bonded to the outer coupling part 120.

(22) As described above, all of the conventional rubber insulators have the same shortest lengths.

(23) In the conventional technology, a portion of the inner coupling part to which the rubber insulator is bonded and a portion of the outer coupling part to which the rubber insulator is bonded have the same shapes as or shapes symmetrical to the shapes of a portion of the inner coupling part to which another rubber insulator is bonded and of a portion of the outer coupling part to which another rubber insulator is bonded, so each of the rubber insulators has also the same shape or a shape symmetrical to each other.

(24) Accordingly, in the conventional technology, all of the rubber insulators have the same natural frequencies, so a large resonance energy K* occurs in the rubber insulators having the same natural frequencies.

(25) Meanwhile, the natural frequency of the rubber insulator is approximately inversely proportional to the square of the length of the rubber insulator.

(26) Accordingly, when the length of the rubber insulator is changed, the natural frequency of the rubber insulator is changed greatly.

(27) In consideration of this, the length of each of the rubber insulators 130 is changed such that the natural frequency of each of the rubber insulators 130 is different from each other, or the length of at least one rubber insulator 130 and the length of another rubber insulator 130 are made to be different from each other such that the natural frequency of the at least one rubber insulator 130 is different from the natural frequency of the another rubber insulator 130. In this case, the resonance frequencies (or peak frequencies) of the rubber insulators 130 having different natural frequencies become different from each other, so the resonance energy of the rubber insulators 130 may be distributed.

(28) Accordingly, to change the length of the rubber insulator 130, the shapes of a portion of an inner coupling part or a portion of an outer coupling part of any one unit vibration damping module are not allowed to be the same as or symmetrical to the shapes of a portion of the inner coupling part and a portion of the outer coupling part of another unit vibration damping module, so the shortest length of the any one unit vibration damping module is different from the shortest length of the another unit vibration damping module.

(29) In the present embodiment, as illustrated in FIG. 6, two protrusion parts 111a and 111b are formed on the outer surface of the inner coupling part 110 by protruding therefrom toward the rubber insulators 130 to have different heights.

(30) Accordingly, in the embodiment, one rubber insulator 130a having the shortest length of La, one rubber insulator 130b having the shortest length of Lb, two rubber insulators 130c having the same lengths Lc as in the conventional technology are provided.

(31) The shortest length of at least one unit vibration damping module is preferably 70% to 98% of the shortest length of another unit vibration damping module.

(32) When the shortest length of the one unit vibration damping module is more than 98% and less than 102% of the shortest length of the another unit vibration damping module, the resonance energy is difficult to be divided owing to ductility of the rubber insulators, so the effect of reducing the resonance energy is insufficient.

(33) In addition, when the shortest length of one unit vibration damping module is less than 70% of the shortest length of another unit vibration damping module, unstable damping as a whole may occur due to rapid change of the resonance energy.

(34) Particularly, the difference between a primary natural frequency of one rubber insulator and a primary natural frequency of another rubber insulator is preferably within 40 Hz to 1000 Hz.

(35) When the difference between the primary natural frequency of one rubber insulator and the primary natural frequency of another rubber insulator is less than 40 Hz, the resonance energy is difficult to be divided owing to ductility of the rubber insulators, so the effect of reducing the resonance energy is insufficient.

(36) In addition, when difference between the primary natural frequency of one rubber insulator and the primary natural frequency of another rubber insulator is more than 1000 Hz, unstable damping as a whole may occur due to rapid change of the resonance energy.

(37) In the embodiment, two rubber insulators 130 have the same shortest lengths Lc, and two other rubber insulators 130 have the shortest lengths La and Lb different from each other.

(38) However, in some cases, all rubber insulators 130 may have the shortest lengths different from each other, or only one rubber insulator 130 may have the shortest length different from the shortest lengths of remaining rubber insulators 130.

(39) FIG. 9 illustrates a dynamic spring constant according to the conventional technology of FIG. 2 and a dynamic spring constant according to the embodiment of the present disclosure of FIG. 6.

(40) In the case of the conventional technology, the peak value of the dynamic spring constant is approximately 6600 N/mm in 1400 to 1500 Hz, but in the case of the embodiment of the present disclosure, the peak value of the dynamic spring constant is approximately 2000 to 2600 N/mm in 1100 Hz to 2500 Hz.

(41) Accordingly, in the embodiment of the present disclosure, the resonance energy K* can decrease to 50% or less of the resonance energy of the conventional technology.

(42) In the embodiment, the protrusion parts 111a and 111b are formed on the inner coupling part 110 such that the shortest lengths of the rubber insulators 130 are changed.

(43) However, according to other embodiments, the protrusion parts may be formed inward on the outer coupling part 120, or the protrusion parts may be formed both on the inner coupling part 110 and on the outer coupling part 120.

(44) In the embodiment, four rubber insulators 130 are provided, but the number of the rubber insulators 130 may be changed according to an embodiment.

(45) In FIGS. 3 and 4 illustrating the conventional technology, two rubber insulators are provided, and when the shortest length of one of the rubber insulators is changed, the objective of the present disclosure can be achieved.

(46) In FIG. 6, the protrusion parts are formed outward on the inner coupling part, and such a method may be applied even in FIGS. 3 and 4.

(47) In addition, apart from such a method forming the protrusion parts, the shape of the inner coupling part or the shape of the outer coupling part may be changed, so the shortest lengths of the rubber insulators located therebetween may be changed.

(48) Additionally, as illustrated in FIG. 1, even in the case of the whole bush-type rubber bushing, the rubber insulator having the shape of a whole bush may be changed to rubber insulators having bridge shapes, and the shortest lengths of the rubber insulators may be designed to be different from each other, thereby reducing the entire resonance energy of the rubber insulators.

(49) The above description of the present disclosure is only for illustrative purposes, and those skilled in the art will appreciate that various modifications are possible without departing from the scope and spirit of the present disclosure. Therefore, it should be understood that the embodiment described above is illustrative in all respects and not limiting. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as being distributed may also be implemented in a combined form.

(50) The scope of the present disclosure is indicated by the claims to be described later rather than the detailed description, and it should be interpreted that all changes or modified forms derived from the meaning and scope of the claims and concept equivalent thereto are included in the scope of the present disclosure.