JP4287927B2 - Liquid seal bush - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a liquid seal bush used for a drive system such as an engine mount and a differential mount of an automobile, a suspension portion, and the like.
[0002]
[Prior art]
Such a liquid seal bush is known. For example, in Japanese Patent No. 2678705, a cylindrical outer cylinder, a core member concentrically arranged on the inside thereof, and an interposition between the outer cylinder and the core member are disclosed. The elastic member is substantially H-shaped in a cross section (axial orthogonal cross section) in a direction orthogonal to the axis of the outer cylinder, and a pair of liquid chambers in the up and down direction in use when sandwiching the core member A pair of cavities are arranged in the front-rear direction, the liquid chambers communicate with each other through an orifice passage, and the wall thickness of the liquid chamber constituted by a part of the elastic member and the vacant partition wall The thing formed thinner than the thickness of the end wall of the elastic member formed in the direction both ends is shown. In addition, in this application, up and down, right and left, and front and rear are based on the vehicle body in an attached state.
[0003]
[Problems to be solved by the invention]
According to the above structure, the thin septal wall against vibration input in the medium frequency region can be realized low dynamic spring by resonating membrane in the vertical direction, the outer edge portion of the elastic member is baked into the outer cylinder side fixation Therefore, as shown in the characteristic curve of FIG. 9 (represented by circled numbers 1, hereinafter abbreviated as circle 1, circle 2,...), It moves near the boundary between the middle frequency region and the high frequency region. It has a minimum value A of the spring characteristic and a large maximum value B due to its reaction. One of the reasons why the minimum value A and the maximum value B occur is that the outer peripheral portion of the partition wall is fixed to the outer cylinder side, so that the spring as a whole becomes a relatively high dynamic spring.
[0004]
Furthermore, in this example, the static spring constant is lowered by causing the bulkhead to extend in the vertical direction with respect to the vibration input in the front-back direction, but the static spring constant is required to be reduced to some extent. In such a case, this known example cannot cope with this case.
[0005]
Accordingly, the present invention is to provide fleet deformation resonance and the elastic member of the liquid to low dynamic spring across the medium frequency region corresponds by arise with respect to orthogonal direction, relative to the other direction It aims at making it respond | correspond by producing a compressive deformation in an elastic member.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, a first invention relating to the liquid seal bushing of the present application includes a cylindrical outer cylinder, a core member disposed on the inside thereof, and interposed between the outer cylinder and the core member. An elastic member, and forming a recess at a symmetrical position sandwiching the core member on the outer peripheral side of the intermediate portion of the elastic member to form a liquid chamber, and partitioning between these liquid chambers by a partition formed by a part of the elastic member, In addition, in the liquid seal bush in which the liquid chambers are communicated with each other through the orifice passage, the liquid chambers are arranged in one direction along the orthogonal vibration input direction within the cross section perpendicular to the axial direction of the outer cylinder. The partition walls are arranged symmetrically with respect to each other, and the partition walls are symmetrically arranged along the other direction with the core member interposed therebetween, and the partition walls are closely contacted to allow the outer edge portion to shift relative to the outer cylinder. A hollow hole formed in the thick wall portion, and a through hole Terra is provided with a pair of thin wall portions facing, with these thin wall portion constitutes a wall portion of each fluid chamber, the compression deformable provided from the core member towards the radial direction of the outer cylinder, each A liquid chamber cover that covers the concave portion is press-fixed to the inner peripheral surface of the outer cylinder, and the circumferential direction of each partition is fixed by the liquid chamber cover .
[0007]
According to a second invention, in the first invention, the pair of thin wall portions opposed to each other with the hollow hole extending linearly from the core member toward the outer cylinder within the cross section in the axis orthogonal direction. It is characterized by being.
[0008]
According to a third aspect of the present invention, in the first aspect, the pair of thin wall portions facing each other with the lightening hole interposed therebetween are curved outward in the cross section in the direction perpendicular to the axis. And
[0009]
According to a fourth invention, in the first invention, the pair of thin wall portions opposed to each other with the hollow hole interposed therebetween are within the cross section in the direction perpendicular to the axis, and one is curved outward as viewed from the liquid chamber, and the other is the inner side It is characterized by being curved to the right.
[0010]
A fifth invention is characterized in that, in the first invention, the base portion of the partition wall pressed against the inner peripheral surface of the outer cylinder is a thin wall portion.
[0011]
A sixth invention is characterized in that, in the first invention, the orifice passage is bent.
[0012]
【The invention's effect】
According to the first aspect of the present invention, the spring constant is lowered by providing the pair of thin wall portions opposed to the partition wall, and the contact portion with the outer cylinder is not coupled. In addition, if there is a vibration input in the middle frequency region in one of the orthogonal vibration input directions in the cross section perpendicular to the axis of the outer cylinder, the elastic member is gradually deformed and a membrane resonance occurs in the thin wall portion of the partition wall, The whole middle frequency region becomes a low dynamic spring.
[0013]
On the other hand, when there is vibration input in the other direction, the pair of thin wall portions facing each other of the partition wall absorbs by causing compressive deformation. At this time, the static spring constant of the partition wall is lowered by the hollow hole, but it can sufficiently cope with this vibration because it is compressed and deformed. As a result, an appropriate elastic balance can be maintained with respect to vibration input in two orthogonal directions.
[0014]
According to the second invention, since the pair of opposing thin wall portions are formed in a straight line, the minimum value C in the intermediate frequency region can be lowered and the high frequency region can be reduced as shown by the characteristic curve (2) in FIG. Since the maximum value D can be lowered, the dynamic spring can be reduced to the high frequency region.
[0015]
According to the third invention, since the pair of opposing thin wall portions are curved outward as viewed from the liquid chamber, the minimum value E in the intermediate frequency region is further increased as shown by the characteristic curve circle 3 in FIG. It becomes low and can be made a lower dynamic spring.
[0016]
According to the fourth aspect of the invention, one of the opposing thin wall portions is curved inwardly, and the other is curved outwardly . Therefore, as shown by the characteristic curve circle 4 in FIG. Does not significantly reduce the dynamic spring, but the second minimum value G can be formed in the high frequency region, thereby reducing the dynamic spring to the high frequency region.
[0017]
According to the fifth invention, it is provided with the thin portion at the base of the partition wall, as shown in characteristic curve circle 5 in FIG. 9, the minimum value H of the middle-frequency region is remarkably low dynamic spring of.
[0018]
According to the sixth aspect of the invention, by bending the orifice passage, flow resistance is generated when the liquid flows through the orifice passage, thereby widening the generation frequency band of the liquid column resonance and securing a wide range of damping characteristics.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to FIGS. 1 is a cross-sectional view (cross-sectional view taken along line 1-1 of FIG. 4) of the liquid seal bushing of the present invention, FIG. 2 is a view showing the liquid seal bush from the axial direction, and FIG. 4 is a longitudinal sectional view of the liquid seal bush (cross section taken along line 4-4 in FIG. 2), FIG. 5 is a view showing the external shape of the elastic member from the X direction in FIG. 1, and FIG. 6 is an enlarged schematic view of the partition wall portion. 7 and FIG. 8 are cross-sectional views corresponding to FIG. 1 of a modified example in which the shape of the partition wall is changed, and FIG. 9 is a graph showing dynamic spring characteristics by this liquid seal bush.
[0020]
In these drawings, the liquid seal bush includes a cylindrical outer cylinder 1, an inner cylinder 2 which is a core member disposed substantially concentrically on the inner side thereof, and an elastic member 3 interposed therebetween. Is provided. The elastic member 3 is formed integrally with the inner cylinder 2 with an appropriate elastic material such as rubber or elastomer, and concave portions 4 and 5 are formed at symmetrical positions with the inner cylinder 2 sandwiched in the middle portion in the longitudinal direction. A part of the elastic member 3 left between the two forms a partition wall 6.
[0021]
The partition wall 6 is formed with a hollow hole 7 penetrating in parallel with the axial direction of the outer cylinder 1 or the inner cylinder 2 (hereinafter simply referred to as the axial direction) in the wall thickness. The hollow hole 7 has a substantially triangular shape in the cross section of FIG. 1, and is arranged with one apex directed toward the inner cylinder 2, and the inner peripheral surface of the outer cylinder 1 among the sides surrounding the hollow hole 7. A portion that abuts the base portion 8 forms a base portion 8, and an orifice groove 9 for forming an orifice passage with the outer cylinder 1 is formed on the outer surface.
[0022]
The base portion 8 is in close contact with the inner peripheral surface of the outer cylinder 1 in a non-bonded state at a length of approximately ¼ arc in the circumferential direction. However, the contact length can be arbitrarily set. Here, the non-bonded state refers to a state in which the outer edge portion and the inner surface of the outer cylinder 1 are allowed to be relatively displaced due to a large load, unlike the conventional baking structure, which is merely pressed.
[0023]
In addition, among the other two sides surrounding the hole 7, the portion facing the recess 4 forms the thin wall portion 10, and the portion facing the recess 5 forms the thin wall portion 11. These thin wall portions 10 and 11 extend and connect the inner cylinder 2 and the outer tube 1 in the radial direction, and the thin wall portions 10 and 11 extend substantially in the front-rear direction in the use state.
[0024]
The recesses 4 and 5 are respectively covered with the liquid chamber covers 12 and 13, and a part of each of the liquid chamber covers 12 and 13 forms stopper protrusions 14 and 15 protruding into the recesses 4 and 5. A space surrounded by the liquid chamber cover 12 and the concave portion 4 forms the first liquid chamber 16, and a space surrounded by the liquid chamber cover 13 and the concave portion 5 forms the second liquid chamber 17.
[0025]
These first and second liquid chambers 16 and 17 are completely the same in capacity and function, and there is no difference between main and sub. Further, the first and second liquid chambers 16 and 17 are arranged in the vertical direction in the use state.
[0026]
The periphery of the liquid chamber covers 12 and 13 is pressure-fixed to the inner peripheral surface of the outer cylinder 1 in a state where the liquid chamber covers 12 and 13 overlap with the elastic members forming the edges of the recesses 4 and 5. In addition, orifice passage communication ports 18 and 19 are formed at portions where the edge portion of the base portion 8 and the edge portions of the liquid chamber covers 12 and 13 are connected, and the first through the communication ports 18 and 19 and the orifice groove 9 The liquid filled in the first and second liquid chambers 16 and 17 flows.
[0027]
As shown in FIG.2 and FIG.4, the part in the axial direction both ends of the inner cylinder 2 among the elastic members 3 becomes the circular end wall 20 which makes a pair integrated with the inner cylinder 2 by baking. Yes. A ring member 21 is partially embedded in the vicinity of each outer peripheral portion of the both end walls 20, and each outer peripheral portion of the both end walls 20 seals a part of the elastic member 3 formed on the outer peripheral portion of the ring member 21. 22 is press-fitted into the inner peripheral surface of the outer cylinder 1.
[0028]
As shown in FIG. 5, the orifice passage 9 is linear. Reference numeral 23 denotes a step for placing the end of the liquid chamber cover 12, and 24 denotes a seal for the orifice passage 9 . Reference numerals 16a and 17a denote concave portions formed in the elastic member 3 so as to form respective liquid chambers.
[0029]
As is apparent from FIG. 6 schematically, the thin wall portions 10 and 11 each form a pair with the hollow hole 7 interposed therebetween, linearly extend in the radial direction of the inner cylinder 2, and as a kind of elastic film The film thickness is set so as to generate film resonance with respect to vibration input in the middle frequency range.
[0030]
The film thickness t of the thin wall portions 10 and 11 is the thickness of the thinnest portion within the range of the thin wall portions 10 and 11 as shown in this figure, and the minimum thickness T of the end wall 20 (see FIG. 4). ) Or less. However, the film thickness t can be arbitrarily set in accordance with the required value of the resonance frequency in a range smaller than T, and is preferably set in the range of 1/3 ≦ t / T ≦ 1/2. This setting can be easily made by adjusting the size of the lightening hole 7.
[0031]
Next, the operation of this embodiment will be described. First, since the thin wall portions 10 and 11 are provided in the partition wall 6 to reduce the spring constant and the contact portion with the outer cylinder 1 is not coupled, the overall low as shown in the characteristic curve circle 2 in FIG. It is a dynamic spring.
[0032]
In addition, if there is a vibration input in the middle frequency range in the vertical direction, the elastic member 3 is gradually deformed, and membrane resonance occurs in the thin wall portions 10 and 11 of the partition wall 6 so that the minimum value C is lowered. As a result, the entire middle frequency region becomes a low dynamic spring.
[0033]
In addition, the maximum value D in the high frequency region is also lowered, and the difference d1 in the minimum value C is smaller than the initial difference d from the conventional example, but the difference d2 in the maximum value D is much larger, and as a result, This portion is clearly a low dynamic spring, and as a whole, it is a low dynamic spring. In the low-frequency region, a low dynamic spring is realized by orifice resonance accompanying the liquid flow between the first and second liquid chambers.
[0034]
On the other hand, if there is a vibration input in the front-rear direction, the thin wall portions 10 and 11 of the partition wall 6 are absorbed by causing compressive deformation. At this time, the partition wall 6 has a low static spring constant due to the lightening hole 7, but can maintain an appropriate elastic balance by causing compression deformation.
[0035]
In addition, this invention is not limited to the said structure, A various deformation | transformation and application are possible. For example, as shown in FIGS. 7 and 8, the characteristics can be easily changed simply by changing the shapes of the thin wall portions 10 and 11. FIG. 7 shows a first modified example in which the thin wall portions 10 and 11 are curved toward each other to the side of the thinning hole 7 (hereinafter referred to as an outer curve when viewed from the liquid chamber side, and the opposite direction is referred to as an inner curve). . In this way, as shown by the characteristic curve circle 3 in FIG. 9, the minimum value E in the intermediate frequency region can be further reduced to a dynamic spring.
[0036]
FIG. 8 shows a second modification in which the thin wall portion 10 is curved inward and the thin wall portion 11 is curved outward. However, it is free to make the thin wall portion 10 bend outward and the thin wall portion 11 be bend inward. In this way, as shown by the characteristic curve circle 4 in FIG. 9 , the minimum value F in the middle frequency region does not become so low as a dynamic spring, but the second minimum value G can be formed in the high frequency region, thereby Low dynamic springs can be achieved up to the high frequency range.
[0037]
10 to 12 show a second embodiment in which a thin wall portion is provided at the base and the orifice passage is deformed. FIG. 10 is a sectional view taken along line 10-10 in FIG. 11, and FIG. 11 is an elastic member in this example. FIG. 12 is a graph showing the attenuation characteristic in this example.
[0038]
As shown in FIG. 11, in this example, it is the thin portion substantially the entire base portion 8. In this way, the minimum value H in the intermediate frequency region is significantly lowered as shown in the characteristic curve circle 5 of FIG. 9 as the difference d3. In this example, the example of FIG. 7 is combined as the thin wall portions 10 and 11, but the example of FIG. 6 or 8 can be freely combined, and the characteristics change depending on each combination.
[0039]
Furthermore, a pair of walls 25 and 26 are provided at the circumferential end of the base 8 so as to extend from opposite sides and alternate, thereby bending the orifice groove 9 in a crank shape.
[0040]
In this way, when the orifice groove 9 is bent in a crank shape, a flow resistance is generated when the liquid flows through the orifice passage 9, and as shown in FIG. 12, the curve of this embodiment becomes gentler. With respect to a predetermined design reference line set to obtain level attenuation, it can be achieved in a frequency band f2 wider than the frequency band f1 of the conventional example. Widely secured. This structure can also be combined with each of the above structures as appropriate.
[Brief description of the drawings]
1 is a cross-sectional view of a liquid seal bush according to a first embodiment (a cross-sectional view corresponding to line 1-1 in FIG. 4).
2 is a view showing the liquid seal bush from the axial direction. FIG. 3 is a view showing the liquid seal bush from the direction orthogonal to the axis. FIG. 4 is a sectional view taken along line 4-4 in FIG. FIG. 6 is a view schematically showing the thin wall portion. FIG. 7 is a view corresponding to FIG. 1 of the first modification in which the thin wall portion is deformed. FIG. 9 is a diagram corresponding to FIG. 1 of the second modified example. FIG. 9 is a dynamic spring characteristic diagram. FIG. 10 is a sectional view showing the elastic member of the second example along line 10-10 in FIG.
11 is a view showing the external shape of an elastic member in this example corresponding to FIG.
FIG. 12 is a diagram of attenuation characteristics of the second embodiment.
1: outer cylinder, 2: inner cylinder, 3: elastic member, 4: recessed portion, 5: recessed portion, 6: partition wall, 7: hollow hole, 8: base, 10: thin wall portion, 11: thin wall portion

Claims (6)

A cylindrical outer cylinder, a core member disposed on the inside, and an elastic member interposed between the outer cylinder and the core member, and sandwiching the core member on the outer peripheral side of an intermediate portion of the elastic member In a liquid seal bushing in which a recess is formed at a symmetrical position to form a liquid chamber, the liquid chamber is partitioned by a partition formed by a part of an elastic member, and the liquid chambers are communicated with each other through an orifice passage. In the cross section perpendicular to the axial direction, the liquid chambers are arranged symmetrically along one direction of the orthogonal vibration input direction with the core member interposed therebetween, and the partition walls are arranged along the other direction. Are arranged symmetrically with respect to each other, and each partition wall is in close contact and non-bonding that allows the outer edge portion to be displaced relative to the outer cylinder, and a thinned hole formed in the thick portion, and this meat It has a pair of thin walls facing each other separated by a punch hole, and these thin walls are With constituting a wall portion of which liquid chamber, the compression deformable disposed toward the radial direction of the outer cylinder from said core member,
A liquid seal bush, wherein a liquid chamber cover that covers each of the recesses is pressed against and fixed to an inner peripheral surface of an outer cylinder, and a circumferential direction of each partition wall is fixed by the liquid chamber cover . 2. The liquid seal bushing according to claim 1, wherein the pair of thin wall portions opposed to each other with the through hole interposed therebetween extend linearly from the core member toward the outer cylinder within the cross section in the direction perpendicular to the axis. . 2. The liquid seal bush according to claim 1, wherein the pair of thin wall portions opposed to each other with the lightening hole interposed therebetween are curved outwardly as viewed from the liquid chamber within the cross section in the direction perpendicular to the axis. 2. A pair of thin wall portions facing each other with the lightening hole interposed therebetween, wherein one of the thin wall portions is curved outward as viewed from the liquid chamber, and the other is curved inward. Liquid seal bush. 2. The liquid seal bush according to claim 1, wherein a base portion of the partition wall pressed against the inner peripheral surface of the outer cylinder is a thin wall portion. 2. The liquid seal bush according to claim 1, wherein the orifice passage is bent.

Images