JP2008190653A - Fluid sealing type compliance bush for suspension - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluid sealing type compliance bush for a suspension capable of advantageously improving riding comfortableness since a predetermined damping effect can be stably provided by high damping characteristics when vibrations such as flatters and brake vibrations of normal magnitudes are input therein and low spring characteristics can be provided at the initial stage when the bush starts to be deflected by the input of an impact load into a wheel. <P>SOLUTION: One-way valve means 56, 74 are installed in a short-circuit flow passage 84 allowing a first fluid chamber 78 to communicate with a second fluid chamber 80. When an impact load from one to the other direction in the longitudinal direction is input into a wheel, a larger flow resistance is developed by the one-way valve means 56, 74 in the fluid flow direction from the second fluid chamber 80 to the first fluid chamber 78 than in the fluid flow direction from the first fluid chamber 78 to the second fluid chamber 80 which is produced in the short-circuit flow passage 84. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a compliance bush for a suspension in which a vehicle suspension arm is connected to the body side in a vibration-proof manner so that an input load in the vehicle front-rear direction from a wheel is exerted in a direction perpendicular to the axis. The present invention relates to a fluid-filled compliance bushing that obtains an anti-vibration effect based on the flow action of a compressive fluid.

  In general, a suspension mechanism of a vehicle such as an automobile has a structure in which a carrier that rotatably supports a wheel is connected to a vehicle body by a suspension arm. As one of such suspension mechanisms, there is known a suspension mechanism that includes a compliance bush that is attached to a portion of the suspension arm that is attached to the body side so that an input load in the vehicle front-rear direction from the wheels is exerted in a direction perpendicular to the axis. . For example, those disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 2002-337527) and Patent Document 2 (Japanese Patent Laid-Open No. 2004-203143) are examples thereof.

  The compliance bush has a structure in which an inner shaft member and an outer cylindrical member spaced apart on the outer peripheral side thereof are elastically connected to each other by a main rubber elastic body, and at a mounting portion of the suspension arm on the vehicle body side, The load applied to the wheel from the longitudinal direction of the vehicle is mounted so as to be exerted in a direction substantially orthogonal to the central axis of the bush, and the load transmitted from the wheel to the body is reduced by the compliance.

By the way, there are various loads applied to the wheels from the front-rear direction of the vehicle in accordance with traveling conditions such as road surface conditions and vehicle characteristics. Therefore, the above-mentioned compliance bush often requires a plurality of vibration isolation characteristics. Among them, the following three anti-vibration characteristics are particularly required.
(1) Reduction of vibrations that cause problems during normal travel such as flutter and brake vibrations (2) Reduction of noise and vibrations caused by road surface unevenness (3) Problems with impact loads applied when overcoming protrusions, etc. Suppressing large vibration transmissions such as harshness and ensuring steering stability

  Here, in order to reduce the vibration (1), it is effective to impart a high damping characteristic to the compliance bush. Therefore, conventionally, in addition to adopting a rubber having a high damping characteristic, application of a liquid seal structure has also been studied in order to obtain a higher damping characteristic. For example, there are those shown in Patent Document 3 (Japanese Patent Laid-Open No. 05-240293) and Patent Document 4 (Japanese Patent Laid-Open No. 2006-2857), and the inner shaft member and the outer cylindrical member excluding the main rubber elastic body. A pair of fluid chambers in which incompressible fluid is sealed between the opposing surfaces and relative pressure fluctuations are generated when vibration is input are positioned opposite to each other in a direction perpendicular to the axis across the inner shaft member. In addition, an orifice passage is formed between the pair of fluid chambers, and both chambers communicate with each other through the orifice passage. According to such a structure, the fluid flow through the orifice passage is generated based on the relative pressure fluctuation between the pair of fluid chambers accompanying the vibration input, and the fluid action such as the resonance action of the fluid. Based on this, a high attenuation effect can be obtained.

  However, as a result of investigation by the present inventors, in the case where a compliance bush having a liquid seal structure is adopted, in addition to the fact that vibration prevention due to the road surface unevenness of (2) is not sufficiently obtained, the above ( It has become clear that the vibration-proof performance against the harshness of 3) is not sufficiently obtained, and the steering stability may be adversely affected.

  In other words, for shock loads such as vibration and harshness caused by road surface unevenness, vibration insulation effect due to shock absorption based on low spring characteristics is effective especially in the initial stage of load input due to fine vibration due to road surface unevenness and harshness. However, as described above, the high damping for the purpose of reducing the vibration in the above (1) is contrary to the realization of the low spring characteristics, and the adoption of the high damping rubber or the fluid sealing structure is the above ( This is contrary to the anti-vibration characteristics against the road surface uneven vibration of 2) and the harshness of the above (3).

  In addition, according to the results of the study by the present inventor, in order to improve the anti-vibration property against the harshness of (3) above, there is a risk that the steering stability may be lowered simply by providing a low spring property. It became clear that it was not effective. That is, if an impact load from the front to the rear is input to the wheel due to a large step on the road surface, the wheel is greatly displaced backward from the center position where no external load in the front-rear direction is applied. Thereafter, due to the elastic elastic body of the compliance bush being greatly bent, a large reaction force is applied from the rear to the front through the suspension arm based on the elasticity of the elastic rubber body. Affected. As a result, the wheel once displaced rearward is likely to be displaced forward beyond the center position, so-called a swinging phenomenon, which may adversely affect the traveling.

  As described above, in order to achieve both the vibration damping characteristics of (1) and (2) and (3), the compliance bush has contradictory characteristics such as a high damping characteristic and a low dynamic spring characteristic. In addition to the realization, it is also important to suppress shaking back caused by harshness, and very high and complex characteristics are required. Here, in the conventional fluid-filled type compliance bush for simply realizing a high damping effect, these required characteristics have not been sufficiently realized.

JP 2002-337527 A JP 2004-203143 A Japanese Patent Laid-Open No. 05-240293 JP 2006-2857 A

  Here, the present invention has been made in the background as described above, and the problem to be solved is that a high damping characteristic can be obtained at the time of normal vibration input from the wheel, thereby achieving the desired vibration isolation. The effect can be exerted advantageously, and at the initial stage where the bush begins to bend as the impact load is applied to the wheels, the low spring characteristics are obtained, so that problematic road surface vibrations are suppressed and riding comfort is advantageous. It is an object of the present invention to provide a fluid-filled compliance bushing for a suspension having a novel structure that can be improved.

  Hereinafter, the aspect of this invention made in order to solve the above-mentioned subject is described. In addition, the component employ | adopted in each aspect as described below is employable by arbitrary combinations as much as possible. Further, aspects or technical features of the present invention are not limited to those described below, but are described in the entire specification and drawings, or an invention that can be understood by those skilled in the art from those descriptions. It should be understood that it is recognized based on thought.

  That is, a feature of the present invention is that the shaft member and the outer cylindrical member arranged at a predetermined distance on the outer peripheral side of the shaft member are elastically connected to each other by the main rubber elastic body, and the suspension arm in the suspension mechanism In a fluid-filled compliance bushing for suspension that is mounted on the vehicle body side of the vehicle body and receives an input load in the vehicle front-rear direction from the wheel in a direction perpendicular to the axis, in a direction perpendicular to the axis across the shaft member A first fluid chamber and a second fluid chamber are formed at opposite positions to generate a relative pressure fluctuation when vibration is input. The first fluid chamber and the second fluid chamber are incompressible. While the fluid is sealed and an orifice passage is formed to communicate the first fluid chamber and the second fluid chamber with each other, a short-circuit channel is formed between the first fluid chamber and the second fluid chamber. But In addition, a one-way valve means is provided in the short-circuit channel, and the first short-circuit channel is generated when an impact load is applied to the wheel from one side to the other in the vehicle front-rear direction. The one-way valve means exerts a larger flow resistance in the fluid flow direction from the second fluid chamber toward the first fluid chamber as compared to the fluid flow direction from the fluid chamber toward the second fluid chamber. The fluid-filled compliance bushing for suspension.

  In such a fluid-filled compliance bush for a suspension having a structure according to the present invention, when an impact load is applied to the wheel from one side to the other in the vehicle longitudinal direction, the second fluid chamber through the short-circuit channel is used. Since the flow resistance of the fluid directed to the first fluid chamber is increased by the one-way valve means as compared with the flow resistance of the fluid directed from the first fluid chamber to the second fluid chamber, The flow of fluid through the first fluid chamber through the second fluid chamber is relatively easily permitted. As a result, the increase in the spring due to the high pressure state of the first fluid chamber due to the impact load input is suppressed, and the impact load is reduced based on the low spring characteristics at the initial stage when the bush begins to bend. The road surface vibration transmitted to the body is advantageously suppressed.

  On the other hand, when a load is applied to the wheel from the other side in the vehicle front-rear direction, the flow resistance of the fluid from the first fluid chamber to the second fluid chamber generated in the short-circuit flow path and the second fluid chamber Since the flow resistance of the fluid toward the first fluid chamber is increased by the one-way valve means, a relatively high damping performance can be obtained. That is, the displacement caused by the load from one side to the other that is exerted on the wheel by reaction when the impact load from one side to the other side of the vehicle in the longitudinal direction of the vehicle is input to the bush is based on the high damping characteristic. Therefore, the so-called swaying back of the wheel, in which the wheel is displaced from the central position to the other position and then returned to the central position and then moved to the other position beyond the central position, is advantageously suppressed.

  Moreover, at the time of vibration input of a normal magnitude such as flutter or brake vibration, the pressure from the first fluid chamber to the second fluid chamber or the pressure from the second fluid chamber to the first fluid chamber is Smaller than those when inputting impact load. In addition, since the orifice passage that communicates the first fluid chamber and the second fluid chamber is always in a communicating state, tuning the orifice passage to vibration of a flutter or the like that should be vibration-isolated makes it possible to input vibration. On the other hand, based on the fluid action such as the resonance action of the fluid that can flow through the orifice passage, it is possible to obtain an effective vibration isolation effect based on the high damping characteristics.

  Therefore, according to the fluid-filled compliance bushing of this structure, the anti-vibration effect due to the high damping characteristics based on the orifice passage is effectively exhibited against the flutter and brake vibration described in (1) above. For the road surface uneven vibration described in the above (2) and the harshness described in the above (3), an anti-vibration effect (impact absorbing effect) is provided by a low dynamic spring characteristic based on a short-circuit flow path that is in a communicating state. It is possible to ensure good maneuvering stability by effectively exhibiting and suppressing the subsequent shaking back by the high damping characteristic based on the short-circuited channel which is in the cut-off state.

  In the present invention, the flow resistance of the fluid from the first fluid chamber to the second fluid chamber and the flow resistance of the fluid from the second fluid chamber to the first fluid chamber generated in the short circuit channel It is not particularly limited whether or not the short-circuit channel is in a closed state when adjusted by the direction valve means. This one-way valve means includes, for example, an elastic valve element that closes the short-circuit channel and an abutment valve seat as described later, or does not block the short-circuit channel and flows on or through the short-circuit channel. You may comprise including the thing like the barrier provided on the extension line of a path | route. Further, as will be described later, the short-circuit channel can be formed independently of the orifice passage, can be formed by the orifice passage, or can be formed by partially using the orifice passage.

  In the fluid-filled compliance bushing for suspension according to the present invention, the one-way valve means includes a contact valve seat and a contact valve seat provided at an opening edge to the first fluid chamber in the short-circuit channel. The elastic valve body is configured to include an elastic valve body that is brought into contact with the pre-compression, and the elastic valve body is elastically deformed when an impact load directed from one side to the other side of the vehicle is applied to the wheel. The first fluid chamber and the second fluid chamber are communicated with each other through a short-circuit flow path, while an impact load is applied to the wheel from the other side of the vehicle in the longitudinal direction of the vehicle or normal vibration input. In this state, a structure in which the short-circuit channel is closed by the elastic valve body being brought into contact with the opening edge of the short-circuit channel to the first fluid chamber with pre-compression is preferably employed. . According to such a structure, the flow of the fluid from the first fluid chamber to the second fluid chamber or from the second fluid chamber to the first fluid chamber is caused by closing the short-circuit channel. The resistance is more reliably exhibited, and the desired high attenuation characteristic can be obtained more advantageously.

  In the fluid-filled compliance bush for suspension according to the present invention, a structure in which the short-circuit channel is formed independently of the orifice channel may be employed. According to such a structure, the degree of freedom in designing the orifice passage and the short-circuit passage is increased, and a more desirable vibration-proofing effect, noise suppression effect, and the like can be expected.

  Furthermore, in the above-described fluid-filled compliance bush for suspension according to the present invention, an orifice passage is formed across one end in the circumferential direction of the first fluid chamber and the second fluid chamber. On the other hand, a structure in which a short-circuit channel is formed between the other ends in the circumferential direction of the first fluid chamber and the second fluid chamber is suitably employed. According to such a structure, space can be efficiently used, and in addition to further improving the degree of freedom in designing each flow path, the compliance bush can be advantageously made compact.

  In the fluid-filled compliance bush for suspension according to the present invention, an intermediate sleeve is arranged at a predetermined distance on the outer peripheral side of the shaft member, and the shaft member and the intermediate sleeve are connected to each other by a main rubber elastic body. And the first pocket portion formed so that the outer cylinder member is fitted and fixed to the intermediate sleeve, and is opened to the outer peripheral surface through the first window portion and the second window portion provided in the intermediate sleeve. And the second pocket portion are fluid-tightly covered to form a first fluid chamber and a second fluid chamber, while an intermediate portion in the axial direction of the intermediate sleeve has a first fluid chamber and a second fluid chamber. A support groove extending in the circumferential direction is formed between the two fluid chambers, an orifice member extending in the circumferential direction is fitted into the support groove, and an outer cylinder member is fitted on the outer peripheral surface of the orifice member. Orifice Structure orifice groove provided on the outer peripheral surface of the wood has an orifice passage is formed by being covering with the outer tube member, may be employed. According to such a structure, the fluid-filled compliance bushing including the first fluid chamber, the second fluid chamber, the orifice passage, and the like can be realized with a relatively simple structure.

  Furthermore, in the fluid-filled compliance bushing for suspension according to the present invention described above, a short-circuit groove is formed on the inner peripheral surface of the orifice member, and the orifice member is fitted and fixed to the support groove of the intermediate sleeve, so that the short-circuit groove. Is covered with the bottom of the support groove to form a short circuit channel, and a contact valve seat is provided at the circumferential edge of the orifice member where one end of the short circuit channel opens. In addition, an elastic valve body integrally formed with the rubber elastic body of the main body protrudes from the bottom of the support groove in the intermediate sleeve, and the orifice member is elastically deformed based on the fixing of the orifice member to the support groove. The structure in which the elastic valve body is brought into contact with the opening edge to the one fluid chamber of the short-circuit channel with pre-compression by being brought into close contact with the contact valve seat in FIG. It is adopted. According to such a structure, the contact valve seat constituting the one-way valve means is provided in the orifice member, and the elastic valve body is integrally formed with the main rubber elastic body, whereby the one-way valve means. An increase in the number of special parts for constituting the valve can be suppressed, and by attaching the orifice member to the intermediate sleeve, the elastic valve body is pre-compressed without any special process, and the one-way valve means is short-circuited. Since the closed state of the flow path is realized, the manufacturing process can be advantageously shortened and the cost can be reduced.

  In this structure, when the elastic valve body is in close contact with the contact valve seat, a large gap is formed between the elastic valve body and the contact valve seat so as to impair the fluid tightness. It means not sticking exactly. Further, in such a contact state, the amount of fluid flow from the first fluid chamber to the second fluid chamber is increased when an impact load is applied to the wheel from one direction to the other in the front-rear direction, and the elastic valve body Based on the elastic deformation, the elastic valve body can be separated from the contact valve seat.

  In the fluid-filled compliance bush for suspension according to the present invention, the suspension arm constituting the suspension mechanism includes a lateral arm portion extending in the lateral direction of the vehicle from the wheel side toward the vehicle body side and a longitudinal arm extending in the longitudinal direction of the vehicle. And a structure in which the first fluid chamber and the second fluid chamber are mounted so as to be opposed to each other in the lateral direction of the vehicle at the mounting portion of the vertical arm portion on the vehicle body side is employed. Also good. According to such a structure, the input load in the vehicle front-rear direction from the wheels is efficiently exerted in the opposing direction of the first fluid chamber and the second fluid chamber with the displacement of the suspension arm, so that the first fluid chamber The fluid flow action between the first fluid chamber and the second fluid chamber is positively permitted or restricted by the one-way valve means, so that both the desired low spring characteristic and high damping characteristic can be achieved to a higher degree. . Therefore, for example, it can be suitably used for the lower arm of the front suspension of automobiles, etc., and it can achieve both the suppression of problematic flutter and brake vibration, etc. and the suppression of road surface unevenness vibration at the time of impact load input at a high level. is there.

  Hereinafter, in order to clarify the present invention more specifically, embodiments of the present invention will be described. First, FIGS. 1 and 2 show a fluid filled compliance bushing 10 for an automobile suspension as an embodiment of the present invention. The fluid-filled compliance bushing 10 includes an inner cylinder fitting 12 as a shaft member and an outer cylinder fitting 14 as an outer cylinder member that are positioned at a predetermined distance in the radial direction and interposed between them. The main rubber elastic bodies 16 are elastically connected to each other.

  More specifically, the inner cylinder fitting 12 has a small-diameter cylindrical shape and is a rigid material formed of, for example, an aluminum alloy. An outer flange-like flange-like portion 18 is integrally formed at one end (left in FIG. 2) in the axial direction of the inner cylinder fitting 12.

  Further, a stopper member 20 is provided on the inner cylinder fitting 12. The stopper member 20 has a substantially rectangular block shape, and is formed using a hard synthetic resin material, a metal material, or the like. The stopper member 20 is insert-molded in the central portion in the axial direction of the inner cylindrical fitting 12 so that the center thereof is inserted into the inner cylindrical fitting 12, and protrudes in the radial direction from the outer peripheral surface of the central portion. It is fixed to the inner cylinder fitting 12. In particular, the pair of end portions in the longitudinal direction of the stopper member 20 project greatly from the inner cylindrical metal member 12 in one radial direction (up and down in FIG. 1), and the projecting tip surface is curved in the circumferential direction. Has been.

  A metal sleeve 22 serving as an intermediate sleeve is disposed on the outer peripheral side of the inner cylindrical metal member 12 provided with the stopper member 20 at a predetermined distance in the radial direction. The metal sleeve 22 has a large-diameter cylindrical shape, and is disposed so as to surround the inner cylinder fitting 12 over the entire circumference. Further, the axial dimension of the metal sleeve 22 is made smaller than the axial dimension of the inner cylindrical metal member 12, and both axial ends of the inner cylindrical metal member 12 are protruded outward in the axial direction from that of the metal sleeve 22. ing.

  A first window portion 24 and a second window portion 26 that open in a rectangular shape in the direction perpendicular to the axis are formed through the central portion of the metal sleeve 22 that is opposed to the metal sleeve 22 in the direction perpendicular to the axis. In the present embodiment, the circumferential lengths of the first window portion 24 and the second window portion 26 are substantially the same, and each has a predetermined length (for example, approximately 1) with respect to the entire circumference of the metal sleeve 22. (A circumferential length of / 6 to 2/5)). The opposing direction of the first window portion 24 and the second window portion 26 is the same as the protruding direction of the tip portion that largely protrudes from the inner cylindrical fitting 12 of the stopper member 20 to both sides in the direction perpendicular to the axis.

  A first connecting plate portion 28 and a second connecting plate portion 30 are provided between the first window portion 24 and the second window portion 26 in the metal sleeve 22 in the circumferential direction. The first connecting plate portion 28 and the second connecting plate portion 30 have a predetermined length in the circumferential direction in a cross section that opens in a concave shape outward in the radial direction, and their circumferential lengths are substantially the same. It is said that. In other words, in the metal sleeve 22, a pair of ring portions 32, 32 having a large-diameter cylindrical shape arranged on the same axis at a predetermined distance in the axial direction straddle between those axially opposed surfaces. The first connecting plate portion 28 and the second connecting plate portion 30 are integrally connected to each other, and the openings between the axially opposed surfaces of the ring portions 32 and 32 are the first and second connecting plate portions 28. , 30, the first window portion 24 and the second window portion are respectively provided between the pair of circumferential directions of the first and second connecting plate portions 28, 30 between the axially facing surfaces of the ring portions 32, 32. 26 is formed. Further, on the outer peripheral surface of the first connecting plate portion 28 or the second connecting plate portion 30, a first support groove as a support groove extending in the circumferential direction with a cross-sectional shape opening in a concave shape radially outward of the metal sleeve 22. 34 and a second support groove 36 are formed.

  A main rubber elastic body 16 is disposed between the inner cylinder fitting 12 and the metal sleeve 22. The main rubber elastic body 16 has a thick, substantially cylindrical shape, and its outer peripheral surface is the inner peripheral surface of the metal sleeve 22, that is, the inner peripheral surface of the pair of ring portions 32, 32, and the first and second connecting plates. The inner peripheral surfaces of the portions 28 and 30 are vulcanized and bonded, and the inner peripheral surfaces thereof are vulcanized and bonded to the outer peripheral surface of the inner cylinder fitting 12 and the outer peripheral surface of the stopper member 20. As a result, the inner cylindrical metal member 12 and the metal sleeve 22 are elastically connected by the main rubber elastic body 16, and the main rubber elastic body 16 is connected to the inner cylindrical metal member 12 and the stopper member 20 as shown in FIGS. , Formed as an integrally vulcanized molded product 38 provided with a metal sleeve 22.

  A thin seal rubber layer 40 formed integrally with the main rubber elastic body 16 is attached to the outer peripheral surfaces of the first and second connecting plate portions 28 and 30 in the metal sleeve 22. Further, a shock-absorbing rubber layer 42 that is integrally formed with the main rubber elastic body 16 is attached to the front end surface of the stopper member 20 that protrudes greatly outward in the radial direction.

  In one radial direction (up and down in FIG. 1) sandwiching the inner cylindrical metal fitting 12 of the main rubber elastic body 16, there are a first pocket portion 44 and a second pocket portion 46 that open in a substantially rectangular shape radially outward. Each of the pocket portions 44 and 46 is open to the outer peripheral surface through the first window portion 24 and the second window portion 26 of the metal sleeve 22. In addition, each protruding tip portion of the stopper member 20 including the buffer rubber layer 42 is projected outward in the radial direction so as not to reach the opening portion from the bottom of each pocket portion 44, 46.

  In the main rubber elastic body 16, a straight portion 48 is formed on the side of the pair of tip portions protruding from the inner cylinder fitting 12 of the stopper member 20 with the inner cylinder fitting 12 sandwiched in one radial direction orthogonal to the protruding direction. Has been. The straight portion 48 extends through the main rubber elastic body 16 in the axial direction and has a predetermined length in the circumferential direction.

  Further, a pair of support rubber layers 50 and 50 protrude on the outer peripheral surfaces of the first connecting plate portion 28 and the second connecting plate portion 30 of the metal sleeve 22, that is, on the first support groove 34 and the second support groove 36. It is installed. The support rubber layer 50 is integrally formed with the main rubber elastic body 16 and protrudes inward in the width direction from the wall portions on both sides in the width direction of the support grooves 34 and 36, and has a substantially rectangular block shape as a whole. Presents.

  In particular, in the pair of support rubber layers 50, 50 projecting from the first connecting plate portion 28, one circumferential side of the second window portion 26 side (the circumferentially clockwise side shown in the upper part in FIG. 1). A pair of abutting protrusions 52, 52 having a rectangular shape are integrally formed at the position biased to protrude inward in the width direction. That is, the pair of contact protrusions 52 and 52 are protruded inward in the width direction from the support rubber layer 50 and are opposed to each other with a predetermined distance in the width direction. In addition, one end in the circumferential direction of the abutment protrusion 52 (the end shown in the upper part in FIG. 4) is one of the circumferential directions of the first connecting plate portion 28 in contact with the opening edge of the second window 26. The other end in the circumferential direction of the contact protrusion 52 (the end shown below in FIG. 4) is positioned on the inner side in the circumferential direction from the end, and the circumferential direction of the first connecting plate portion 28. It is located at the approximate center part of. In addition, a recess that opens in a rectangular concave shape toward the inner side in the width direction is provided in the center portion in the circumferential direction of each support rubber layer 50, and one end in the circumferential direction of each recess has each contact protrusion. 52 is in contact with the other end portion in the circumferential direction. The pair of recesses and the other end in the circumferential direction of the pair of contact protrusions 52, 52 cooperate to open from the bottom of the first support groove 34 in a rectangular concave shape outward in the radial direction. A recess 54 is formed.

  Further, a rubber valve 56 as an elastic valve body protrudes between the opposing surfaces of the pair of contact protrusions 52, 52 in the first connecting plate portion 28. The rubber valve 56 has a substantially rectangular block shape projecting radially outward from the outer peripheral surface of the bottom portion of the first connecting plate portion 28, that is, the bottom surface of the first support groove 34, and is integrally formed with the main rubber elastic body 16. Has been. The rubber valve 56 is positioned at a substantially central portion between the opposed surfaces of the pair of contact projections 52, 52, and is opposed to each contact projection 52 with a predetermined distance in the width direction. Yes. Further, one end surface of the rubber valve 56 in the circumferential direction (upward in FIG. 4) is inclined toward the other side in the circumferential direction from the proximal end side protruding from the first connecting plate portion 28 toward the distal end side in the protruding direction. It is supposed to be an inclined surface. One end portion in the circumferential direction of the rubber valve 56 is positioned on the inner side in the circumferential direction with respect to one end portion in the circumferential direction of the first connecting plate portion 28 in contact with the opening edge portion of the second window portion 26.

  In particular, in this embodiment, the other end in the circumferential direction of rubber valve 56 (downward in FIG. 4) is more circumferential than the other circumferential end of abutment projection 52 projecting from each support rubber layer 50. It extends slightly to the other side in the direction and is positioned in the fitting recess 54.

  With respect to the integrally vulcanized molded product 38 of the main rubber elastic body 16 provided with the inner cylindrical metal member 12 and the metal sleeve 22, the circumferential direction between the first pocket portion 44 and the second pocket portion 46 is straddled. An orifice member 58 is assembled. The orifice member 58 according to the present embodiment is configured by combining the first orifice forming member 60 and the second orifice forming member 62 in the circumferential direction, and as a whole, has a length of slightly less than one round in the circumferential direction. It extends.

  As shown in FIGS. 5 and 6, the first orifice forming member 60 and the second orifice forming member 62 have a circular arc plate shape extending in the circumferential direction with a length of a little less than a half circumference. It is formed using a hard material such as a resin material or a metal material. The width dimension of the circumferential intermediate part of the orifice forming members 60 and 62 is made larger than the width dimension of both circumferential part. Further, the first orifice forming member 60 and the second orifice forming member 62 have first and second outer circumferential surfaces that are continuously extended with a predetermined length in the circumferential direction in a substantially constant valley-like cross section. The orifice groove 64 and the second orifice groove 66 are respectively formed. One end in the circumferential direction of each orifice groove 64, 66 (the end in the clockwise direction shown in the upper direction in FIGS. 5 and 6) opens to one end face in the circumferential direction of each orifice forming member 60, 62. ing.

  The portions of the first orifice forming member 60 and the second orifice forming member 62 that are biased toward the other circumferential side (downward in FIGS. 5 and 6) have a substantially rectangular cross section in the thickness direction in the axial direction. A first continuous window 68 and a second communication window 70 penetrating therethrough are formed. The other end portions in the circumferential direction of the first orifice groove 64 and the second orifice groove 66 are connected to the first continuous window 68 and the second communication window 70. In particular, in the present embodiment, the second communication window 70 is notched by opening the other circumferential edge of the second communication window 70 at the other circumferential edge of the second orifice forming member 62. It has a window shape.

  Further, on the inner peripheral surface of the first orifice forming member 60, a short circuit that extends in the circumferential direction between the other end in the circumferential direction and the other end edge in the circumferential direction of the first series passage window 68 and opens at both ends. A groove 72 is formed. Further, in the first orifice forming member 60, the width dimension of the part provided with the short-circuit groove 72 is made larger than the width dimension or the like of the part provided with the first series of through windows 68.

  As shown in FIGS. 7 and 8, the circumferential intermediate portions of the first and second orifice forming members 60 and 62 are integrally vulcanized molded products 38 of the main rubber elastic body 16 from the radially outer side. Are fitted in the first and second pocket portions 44 and 46, and are opposed to each protruding tip portion of the stopper member 20 at a predetermined distance in the radial direction.

  Further, one end portion in the circumferential direction of the first orifice forming member 60 (end portion in the counterclockwise direction in FIG. 1) and one end portion in the circumferential direction of the second orifice forming member 62 (in FIG. (Clockwise ends) are overlapped with each other in the circumferential direction, and are fitted into the second support groove 36 of the second connecting plate portion 30 in the metal sleeve 22 so as to protrude from the second support groove 36. The pair of supporting rubber layers 50 and 50 are elastically sandwiched in the width direction. In addition, one end in each circumferential direction of the first orifice groove 64 and the second orifice groove 66 is connected to each other.

  Further, the other end portion in the circumferential direction of the first orifice forming member 60 (the end portion in the clockwise direction in FIG. 1) is fitted into the first support groove 34 of the first connecting plate portion 28 in the metal sleeve 22. The pair of support rubber layers 50 and 50 projecting from the first connecting plate portion 28 are in contact with the other circumferential end (downward in FIG. 8) of each contact protrusion 52, It is fitted into a fitting recess 54 positioned on one side in the circumferential direction across the rubber valve 56, and elastically in the width direction by a pair of support rubber layers 50, 50 constituting the fitting recess 54. It is pinched. Further, the other end portion in the circumferential direction of the second orifice forming member 62 (the end portion in the counterclockwise direction in FIG. 1) is fitted into the first support groove 34, so that the pair of support rubber layers 50, 50 A pair of support rubber layers 50 that are in contact with one end (upward in FIG. 8) of each contact protrusion 52 and positioned on the other side in the circumferential direction with the rubber valve 56 interposed therebetween. , 50 are elastically sandwiched in the width direction. Thereby, the orifice member 58 composed of the first and second orifice forming members 60 and 62 is fixedly assembled to the integrally vulcanized molded product 38 of the main rubber elastic body 16.

  Particularly in the present embodiment, the rubber valve protruded into the fitting recess 54 when the other end in the circumferential direction of the first orifice forming member 60 is fitted into the fitting recess 54 of the metal sleeve 22. The other circumferential end of 56 is brought into contact with a circumferential end around the opening edge of the short-circuit groove 72 of the first orifice forming member 60, and the rubber valve 56 is connected to the first connecting plate portion 28. In FIG. 2, the elastic member is elastically deformed by being pushed up from the first window portion 24 toward the second window portion 26. Thereby, the pre-compression is exerted on the rubber valve 56 in the direction from the first window portion 24 toward the second window portion 26, and the rubber valve 56 is formed on the first orifice forming member 60 based on its elastic deformation action. The short-circuit groove 72 is in close contact with the circumferential end around the opening edge. As is clear from this, in this embodiment, the circumferential end around the opening edge of the short-circuit groove 72 of the first orifice forming member 60 abuts while the rubber valve 56 is pre-compressed. Thus, one opening portion of the short-circuit groove 72 is fluid-tightly covered and a contact valve seat 74 that contacts the rubber valve 56 by the circumferential end portion is configured.

  The outer cylinder fitting 14 is assembled to the integrally vulcanized molded product 38 of the main rubber elastic body 16 to which the orifice member 58 is assembled. The outer cylinder fitting 14 has a large-diameter, generally cylindrical shape, and is a rigid material formed of, for example, an aluminum alloy. The axial dimension of the outer cylinder fitting 14 is substantially the same as the axial dimension of the metal sleeve 22. On the inner peripheral surface of the outer cylindrical metal member 14, a thin seal rubber layer 76 that is spread over the entire surface with a substantially constant thickness is formed. Thus, the outer cylinder fitting 14 is extrapolated to the integrally vulcanized molded product 38 of the main rubber elastic body 16, and the outer cylinder fitting 14 is subjected to diameter reduction processing such as eight-way drawing.

  Thus, the outer cylinder fitting 14 is fitted and fixed to the metal sleeve 22 via the seal rubber layer 76, and is positioned substantially concentrically outwardly in the radial direction of the inner cylinder fitting 12. In particular, based on the fact that a plurality of seal lips formed integrally with the seal rubber layer 76 are interposed between the outer cylinder fitting 14 and the ring portions 32 of the metal sleeve 22 while being compressed and deformed, the outer cylinder fitting 14 is While being fixed to the pair of ring portions 32 and 32 in a fluid-tight manner, the opening portion of the first pocket portion 44 and the opening portion of the second pocket portion 46 are covered with a fluid-tight cover by the outer cylindrical fitting 14.

  In a space fluid-tightly defined by the first pocket portion 44 and the outer cylindrical fitting 14 and a space fluid-tightly defined by the second pocket portion 46 and the outer cylindrical fitting 14, a part of the wall portion is the main body. A first fluid chamber 78 and a second fluid chamber 80 are formed which are constituted by the rubber elastic body 16 and cause pressure fluctuations based on the elastic deformation of the main rubber elastic body 16. These first and second fluid chambers 78 and 80 are filled with an incompressible fluid. As such an incompressible fluid, water, alkylene glycol, polyalkylene glycol, silicone oil or the like is adopted. However, in order to advantageously obtain a vibration isolation effect based on a fluid action such as a resonance action of the fluid described later, the viscosity is A low viscosity fluid of 0.1 Pa · s or less is suitably employed. In short, a first fluid chamber 78 and a second fluid chamber 80 filled with an incompressible fluid are formed inside the compliance bushing 10 according to the present embodiment, and the fluid chambers 78 and 80 are inside. They are formed so as to be opposed to each other in one radial direction across the cylindrical fitting 12. The first and second fluid chambers 78 and 80 are filled with the incompressible fluid, for example, in an incompressible fluid, an integrally vulcanized molded product of the main rubber elastic body 16 in which the orifice member 58 is assembled. This is advantageously realized by assembling the outer cylindrical fitting 14 to the 38 assembled bodies.

  Further, the outer cylinder fitting 14 is fitted on the outer peripheral surface of the orifice member 58, and the outer peripheral surface of the orifice member 58 and the inner peripheral surface of the outer cylinder fitting 14 are fluid-tightly overlapped with the seal rubber layer 76 interposed therebetween. Thus, the openings of the first and second orifice grooves 64 and 66 connected to each other in the circumferential direction are covered fluid-tightly by the outer cylinder fitting 14 with the seal rubber layer 76 interposed therebetween. Based on this, an orifice passage 82 extending in a tunnel shape is formed between the metal sleeve 22 and the outer cylindrical fitting 14 in a circumferential direction with a predetermined length (a length of a little less than one round in the present embodiment). One end of the orifice passage 82 is connected to the first fluid chamber 78 through a first series of windows 68 formed in the first orifice forming member 60, and the other end of the orifice passage 82 is connected to the first fluid chamber 78. The second orifice forming member 62 is connected to the second fluid chamber 80 through the second communication window 70. Thereby, the first fluid chamber 78 and the second fluid chamber 80 are communicated with each other through the orifice passage 82, and the orifice passage is based on the relative pressure fluctuations of the two chambers 78, 80 at the time of vibration input. The amount of fluid flow through 82 is ensured, and the anti-vibration effect is exhibited based on the fluid action such as the resonance action of the fluid.

  The resonance frequency of the fluid that flows through the orifice passage 82 based on the difference in relative pressure fluctuation generated between the first fluid chamber 78 and the second fluid chamber 80 when vibration is input is, for example, about 10 to 20 Hz. It is tuned so as to advantageously exhibit an anti-vibration effect (high damping characteristic) based on the resonance action of the fluid against vibrations to be anti-vibrated such as flutter and brake vibration. The tuning of the orifice passage 82 takes into account, for example, the rigidity of the wall springs of the first fluid chamber 78 and the second fluid chamber 80 (characteristic values corresponding to the amount of pressure change necessary for changing the unit volume). However, it can be performed by adjusting the passage length and the passage cross-sectional area of the orifice passage 82. Generally, the frequency at which the phase of the pressure fluctuation transmitted through the orifice passage 82 is changed to be in a substantially resonant state is This can be grasped as the tuning frequency of the orifice passage 82.

  Further, the first orifice forming member 60 is sandwiched between the metal sleeve 22 and the outer cylindrical metal member 14 in the radial direction, and the inner peripheral surface of the other end in the circumferential direction of the first orifice forming member 60 is the first. It is formed on the inner peripheral surface of the first orifice forming member 60 by being fluid-tightly superimposed on the outer peripheral surface of the first connecting plate portion 28 via the seal rubber layer 40 attached to the connecting plate portion 28. The short-circuit groove 72 is covered fluid-tightly by the first connecting plate portion 28 to form a short-circuit channel 84. One end of the short-circuit channel 84 is connected to the first fluid chamber 78 through the first series of windows 68. The other end of the short-circuit channel 84 is fluid-tightly closed by the rubber valve 56 and is connected to the second fluid chamber 80 through the second communication window 70 with the rubber valve 56 interposed therebetween. . That is, in the present embodiment, an orifice passage 82 is formed between one circumferential direction of the first fluid chamber 78 and the second fluid chamber 80, and the first fluid chamber 78 and the second fluid chamber 80. A short-circuit channel 84 is formed between the other circumferential directions of the two, and the orifice channel 82 and the short-circuit channel 84 are formed independently of each other. In addition, the passage cross-sectional areas of the short-circuit channel 84 and the orifice channel 82 are substantially the same, and the channel length of the short-circuit channel 84 is sufficiently shorter than the channel length of the orifice channel 82. Therefore, the short-circuit channel 84 is made sufficiently smaller than the orifice channel 82 with respect to the flow resistance of the fluid between the first fluid chamber 78 and the second fluid chamber 80.

  The pre-compression force is applied to the rubber valve 56 in the direction from the first fluid chamber 78 to the second fluid chamber 80, and in the direction from the second fluid chamber 80 to the first fluid chamber 78. Due to the elastic deformation action, the rubber valve 56 is in close contact with the contact valve seat 74 of the first orifice forming member 60. In particular, even when a relative pressure difference between the first fluid chamber 78 and the second fluid chamber 80 is exerted on the rubber valve 56 at the time of vibration input having a normal magnitude of the tuning frequency of the orifice passage 82, the rubber The precompression force is set so that the rubber valve 56 is brought into contact with the contact valve seat 74 of the first orifice forming member 60 based on the elasticity of the valve 56. As a result, the short-circuit channel 84 is closed. Further, the pressure of the fluid from the second fluid chamber 80 toward the first fluid chamber 78 is exerted on the rubber valve 56, so that the rubber valve 56 is brought into contact with the contact valve seat 74 with a larger deformation action. Thus, the closed state of the short-circuit channel 84 is further ensured.

  On the other hand, an impact load such as harshness which is a problem is input from the second fluid chamber 80 toward the first fluid chamber 78 and is passed from the first fluid chamber 78 to the second fluid chamber 80 through the short-circuit channel 84. When a large fluid flow is generated in the direction of the direction, the rubber valve 56 is elastic from the first fluid chamber 78 toward the second fluid chamber 80 against the elastic deformation force of the rubber valve 56 due to pre-compression. The pre-compression force is set so that the closed state of the short-circuit channel 84 is released by deformation and the first fluid chamber 78 and the second fluid chamber 80 are communicated with each other through the short-circuit channel 84. .

  In other words, the rubber valve 56 is elastically deformed and separated from the contact valve seat 74 when an impact load directed from one to the other in the vehicle front-rear direction is input to the wheel while the compliance bush 10 is mounted on an automobile described later. When the pressure of the first fluid chamber 78 is increased and the rubber valve 56 and the contact valve seat 74 are separated from each other, the second fluid chamber 80 generated in the short-circuit channel 84 is changed from the first fluid chamber 78. The resistance of the fluid flow toward the first fluid chamber 78 is made larger than the resistance of the fluid flow toward the second fluid chamber 80 from the first fluid chamber 78. As a result, the flow of fluid from the first fluid chamber 78 to the second fluid chamber 80 through the short-circuit channel 84 is advantageously allowed by the separated state of the rubber valve 56 and the contact valve seat 74, and An increase in pressure in one fluid chamber 78 is suppressed.

  In addition, when an impact load is applied to the wheel from the other side in the vehicle longitudinal direction to the other side, the pre-compressed rubber valve 56 is applied to the contact valve seat 74 even if the pressure in the second fluid chamber 80 increases. On the other hand, the closed state of the short-circuit channel 84 is maintained by being elastically deformed and abutting in the direction from the second fluid chamber 80 toward the first fluid chamber 78, in addition to the second fluid chamber 80. Since the large pressure (positive pressure) in the fluid chamber 80 is exerted on the rubber valve 56, the short-circuit channel 84 is more reliably closed. As a result, the flow resistance of the fluid from the first fluid chamber 78 to the second fluid chamber 80 and the flow resistance of the fluid from the second fluid chamber 80 to the first fluid chamber 78 generated in the short-circuit channel 84. However, both are increased by the contact state of the rubber valve 56 and the contact valve seat 74 that close the short circuit channel 84, and the pressure through the short circuit channel 84 between the first and second fluid chambers 78 and 80 is increased. Leakage is suppressed.

  The one-way valve means according to this embodiment includes a rubber valve 56 and a contact valve seat 74, and in particular, according to the one-way valve means of this structure, the first fluid chamber 78 and the second fluid Since the relative pressure difference generated between the chambers 80 is exerted on the rubber valve 56, the short-circuit channel 84 is more reliably opened and closed due to the separation or contact of the rubber valve 56 with the contact valve seat 74. It is.

  In the fluid-filled compliance bushing 10 for an automobile suspension structured as described above, for example, between an L-shaped lower arm 86 and a vehicle body 88 as a suspension arm used for an automobile front suspension as shown in FIG. It comes to be attached to.

  As is well known, the lower arm 86 is a substantially L-shaped arm in plan view, and a ball joint (not shown) is disposed on the outer end 90 located on the vehicle outer side (right side in FIG. 9). And can be attached to the wheel via a carrier. Further, on the inner side of the vehicle (left side in FIG. 9), an inner front end portion 92 and an inner rear end portion 94 that are provided apart from each other in the longitudinal direction of the vehicle (up and down in FIG. 9) are respectively provided with a lower arm 86. An anti-vibration bushing for anti-vibration connection to 88 is attached. In the lower arm 86, a portion extending on the horizontal axis: l1 extending in the substantially left-right direction (left and right in FIG. 9) of the vehicle through the center of the outer end portion 90 and the center of the inner front end portion 92 is the horizontal arm portion 96. In addition, a portion extending on the longitudinal axis l2 extending in the vehicle front-rear direction through the center of the inner front end portion 92 and the center of the inner rear end portion 94 is a vertical arm portion 98.

  The anti-vibration bush 100 disposed at the inner front end 92 of the lower arm 86 is similar to, for example, a rubber bush disposed at the inner front end of the lower arm disclosed in Patent Document 1 (Japanese Patent Application Laid-Open No. 2002-337527). The inner shaft member and the outer cylinder member arranged on the outer peripheral side thereof are elastically connected to each other by a main rubber elastic body. The anti-vibration bush 100 has an outer cylinder member fixed to an arm eye extending in the vehicle front-rear direction at the inner front end portion 92 by press-fitting or the like, and an inner shaft member is fixed to the vehicle body, whereby the bush central axis is fixed to the vehicle front-rear. Extending in the direction, it is arranged between the lower arm 86 and the vehicle body 88 and is connected to the vehicle body 88 in a vibration-proof manner.

  In addition, the fluid-filled compliance bush 10 according to the present embodiment is employed as a vibration-proof bush that is mounted between the inner rear end 94 of the lower arm 86 and the vehicle body 88. That is, a rod-shaped inner rear end portion 94 extending in the vehicle front-rear direction is inserted into the inner cylinder fitting 12 from the flange-like portion 18 side of the inner cylinder fitting 12 of the compliance bush 10 and fixed with a bolt or the like. Further, the mounting bracket 102 is fixed to the outer cylinder fitting 14 of the compliance bush 10, and the mounting bracket 102 is fixed to the vehicle body 88 using bolts or the like. Thus, the fluid filled compliance bushing 10 is disposed between the lower arm 86 and the vehicle body 88 so that the bush central axis extends in the vehicle front-rear direction, and the lower arm 86 is connected to the vehicle body 88 in a vibration-proof manner. In addition, an input load in the vehicle front-rear direction from the wheels is exerted in a direction perpendicular to the axis of the bush 10 via the lower arm 86.

  When the fluid-filled compliance bush 10 is mounted on the front suspension mechanism, the opposing direction of the first fluid chamber 78 and the second fluid chamber 80 in the bush 10 extends in the left-right direction of the vehicle. Is positioned on the vehicle inner side (left side in FIG. 9) with the bush central axis extending in the longitudinal direction of the vehicle, and the second fluid chamber 80 is on the vehicle outer side (in FIG. 9) with the bush central axis in between. , Right side). Further, the pair of straight portions 48, 48 in the bush 10 are opposed to each other in the vertical direction of the vehicle.

  Further, regarding the static spring characteristics of the fluid-filled compliance bush 10 and the vibration-proof bushing 100, the vibration-proof bush 100 is harder than the fluid-filled compliance bush 10.

  In the suspension mechanism including the fluid-filled compliance bush 10, when a load in the vehicle front-rear direction is applied to the wheel, the suspension is supported from the wheel via the lower arm 86 by the compliance of the vibration-proof bush 100 and the fluid-filled compliance bush 10. The load transmitted to the vehicle body 88 is reduced. In particular, since the static spring of the vibration isolating bush 100 is harder than the static spring of the fluid-filled compliance bushing 10, when a longitudinal load from the wheel is input to the lower arm 86, the main displacement of the lower arm 86 is reduced. The outer end 90 fixed to the wheel side and the inner rear end 94 fixed to the fluid filled compliance bush 10 are integrally displaced with the inner front end 92 to which the vibration isolating bush 100 is fixed as a fulcrum. It is like that. In other words, the outer end 90 is displaced from the front to the rear and the inner rear end 94 is displaced from the outside to the inside of the vehicle by the input of the load from the front to the rear of the vehicle. In addition, the outer end 90 is displaced from the rear to the front and the inner rear end 94 is displaced from the inner side of the vehicle to the outer side by the input of the load from the rear of the vehicle toward the front. As the inner rear end 94 is displaced in the left-right direction of the vehicle, the inner cylinder fitting 12 is displaced in the left-right direction of the vehicle with respect to the outer cylinder fitting 14, and the first fluid chamber is positioned opposite to the left-right direction of the vehicle. A relative pressure variation occurs between the 78 second fluid chambers 80.

  When vibration such as flutter or brake vibration in the tuning frequency range of the orifice passage 82 is input to such a suspension mechanism, relative pressure fluctuation is effective between the first fluid chamber 78 and the second fluid chamber 80. The fluid flow amount is sufficiently secured by the resonance action of the fluid through the orifice passage 82 and the like. Further, the contact state between the rubber valve 56 and the contact valve seat 74 due to pre-compression is not released with the magnitude of the pressure fluctuation between the first fluid chamber 78 and the second fluid chamber 80 due to the vibration input. Therefore, the closed state of the short-circuit channel 84 is maintained, thereby causing a pressure leak through the short-circuit channel 84 between the first fluid chamber 78 and the second fluid chamber 80. The amount of fluid flow through the orifice passage 82 is not impaired. Accordingly, an excellent vibration isolation effect can be exhibited by the high damping characteristics based on the flow action such as the resonance action of the orifice passage 82.

  There, when an automobile travels over a step or has a large uneven surface, an impact load is input to the wheels from the front of the vehicle, which is one of the front and rear directions of the vehicle, to the rear, which is the other of the front and rear directions of the vehicle. The inner rear end portion 94 of the lower arm 86 is suddenly or excessively displaced from the inner side to the outer side of the vehicle, so that an excessive pressure is generated in the first fluid chamber 78. This pressure is applied to the rubber valve 56 through the short-circuit channel 84, and the rubber valve 56 moves from the first fluid chamber 78 toward the second fluid chamber 80 against the elastic deformation force of the rubber valve 56 due to pre-compression. Since the precompression force of the rubber valve 56 is set to such an extent that the rubber valve 56 is elastically deformed, the closed state of the short-circuit channel 84 is released when the impact load is input, and the first fluid chamber 78 and the second fluid The chambers 80 are communicated with each other through the short-circuit channel 84. As a result, the pressure of the first fluid chamber 78 is sufficiently larger than the pressure of the second fluid chamber 80, so that the first fluid chamber 78 generated in the short-circuit channel 84 is changed from the first fluid chamber 78 to the second fluid chamber 80. A larger flow resistance is exhibited in the fluid flow direction from the second fluid chamber 80 toward the first fluid chamber 78 as compared with the fluid flow direction toward the first fluid chamber 80. The flow of fluid from one fluid chamber 78 to the second fluid chamber 80 is advantageously permitted. Accordingly, the high dynamic spring due to the high pressure state of the first fluid chamber 78 due to the shock load input is suppressed, and the impact load is reduced based on the low spring characteristics at the initial stage where the bush 10 starts to bend. Thus, road surface vibration transmitted from the wheel to the body is advantageously suppressed.

  Further, when the center of the inner rear end portion 94 displaced from the vehicle outer side toward the inner side of the lower arm 86 is displaced again so as to be positioned on the longitudinal axis 12, the outer end portion 90 of the lower arm 86 moves forward from the vehicle rear side. As the vehicle is displaced toward the vehicle, a load from the rear to the front of the vehicle is input to the wheels. At that time, the pressure of the fluid from the second fluid chamber 80 toward the first fluid chamber 78 is exerted on the rubber valve 56, so that the rubber valve 56 that has been in contact with the contact valve seat 74 with pre-compression is applied to the rubber valve 56. On the other hand, an elastic deformation action is further exerted in the direction toward the contact valve seat 74, and the contact state is further ensured. As a result, the contact state between the rubber valve 56 and the contact valve seat 74 is maintained while the pressure in the second fluid chamber 80 is sufficiently higher than the pressure in the first fluid chamber 78. As a result, the flow resistance of the fluid from the first fluid chamber 78 to the second fluid chamber 80 and the flow resistance of the fluid from the second fluid chamber 80 to the first fluid chamber 78 generated in the short-circuit channel 84. Is increased. As a result, the closed state of the short-circuit channel 84 is suitably maintained, and pressure leakage through the short-circuit channel 84 between the first and second fluid chambers 78 and 80 is suppressed, so that a relatively high attenuation performance is achieved. Is obtained. Therefore, the load from the rear to the front acting on the wheel reactively by the impact load from the front to the rear of the wheel being input to the fluid-filled compliance bushing 10 is reduced based on the high damping characteristics. The so-called swinging back of the wheel, in which the wheel is displaced rearward from the center position supported by the carrier and returned to the center position and then moved forward beyond the center position, is advantageously suppressed.

  Therefore, when the fluid filled compliance bushing 10 according to the present embodiment is employed in the suspension mechanism, a low spring characteristic is exhibited when an impact load from the front of the vehicle toward the rear is input to the wheels. Road surface vibration, which is a problem with ease of transmission in the spring state, is reduced, and an excellent riding comfort can be obtained. In addition, when the load is applied from the rear to the front of the wheel, or when normal vibration such as flutter or brake vibration is input, the high damping characteristics are exhibited, so that the wheel does not swing back and has excellent operability. In addition to being obtained, the desired anti-vibration effect can be stably obtained.

  In this embodiment, a stopper mechanism including the stopper member 20 and the buffer rubber layer 42 is provided in the first and second fluid chambers 78 and 80 so that the first fluid chamber 78 and When an excessive load is input in the opposite direction of the second fluid chamber 80 and the inner cylinder fitting 12 and the outer cylinder fitting 14 abut against each other via the stopper mechanism, the relative displacement of the inner and outer cylinder fittings 12, 14 is achieved. The amount is buffered. Thereby, it is possible to more advantageously suppress the above-described shaking back and the like.

  As mentioned above, although one embodiment of the present invention has been described in detail, the present invention is not limited in any way by the specific description in the embodiment, and various changes, modifications, and modifications based on the knowledge of those skilled in the art. Needless to say, the present invention can be implemented in a mode with improvements and the like, and all such modes are included in the scope of the present invention without departing from the gist of the present invention.

  For example, the shape, size, structure, number, arrangement, etc. of the rubber valve 56, the first and second fluid chambers 78, 80, the orifice passage 82, and the short-circuit passage 84 are limited to those illustrated. Not a thing. Specifically, in the embodiment, a set of the first fluid chamber 78 and the second fluid chamber 80 is provided, and the short-circuit channel 84 is provided between the first fluid chamber 78 and the second fluid chamber 80. Although one set of rubber valves 56 is provided, a plurality of sets of these first and second fluid chambers, short-circuit flow paths, and rubber valves may be provided.

  In the embodiment, the orifice passage 82 is provided between the first fluid chamber 78 and the second fluid chamber 80 in the circumferential direction, and the short-circuit channel 84 is connected to the first fluid chamber 78 and the first fluid chamber 78. Although the orifice passage 82 and the short-circuit passage 84 are formed independently of each other by being provided between the other circumferential directions of the two fluid chambers 80, for example, the first and second fluid chambers 78, 80 are formed. It is also possible to provide an orifice passage and a short-circuit channel between one end portion between them, and further, an orifice channel and a short-circuit channel can be formed using a part of each other.

  Furthermore, in the above-described embodiment, in the direction of fluid flow from the first fluid chamber 78 to the second fluid chamber 80 generated in the short-circuit channel 84 when an impact load is applied to the wheels from the front to the rear of the vehicle. In contrast, when a greater flow resistance is exerted in the fluid flow direction from the second fluid chamber 80 toward the first fluid chamber 78, the rubber valve 56 to which pre-compression is applied is brought into contact with the contact valve seat 74. Although the short-circuit channel 84 is closed due to contact, it is essential to adopt the rubber valve 56 and the contact valve seat 74 as a one-way valve means or to close the short-circuit channel 84. It is not a configuration requirement. Specifically, for example, a barrier is provided so as to face the opening edge of the short-circuit channel opening at the circumferential end of the first orifice forming member at a predetermined distance in the circumferential direction, and the above-described fluid The barrier can be made of an elastic member so that the flow direction can be adjusted.

  In addition, in the above-described embodiment, the present invention is applied to a compliance bushing in which the lower arm of the front suspension mechanism of the automobile is connected to the vehicle body in a vibration-proof manner. However, the present invention is not limited to the rear suspension mechanism of the automobile. In addition to the compliance bushing for connecting the trailing arm to the vehicle body in an anti-vibration manner, any of them can be applied to the compliance bushing for suspensions of various vehicles other than automobiles.

  Moreover, in the said embodiment, the opening part by the side of the 2nd fluid chamber 80 side of the short circuit flow path 84 is input at the time of the input of the impact load which goes to the back which becomes the other in the vehicle front-back direction from the front which becomes one in the vehicle front-back direction to a wheel. The rubber valve 56 provided in the elastic member is elastically deformed to be separated from the contact valve seat 74, and the first fluid chamber 78 and the second fluid chamber 80 are communicated with each other through the short-circuit channel 84. On the other hand, when the load is applied to the wheels from the rear to the front of the vehicle, the rubber valve 56 is brought into contact with the contact valve seat 74 and the short-circuit channel 84 is closed, thereby obtaining a high damping characteristic. It was supposed to be. However, this form only shows one aspect of the specific required characteristics under application to the front suspension mechanism as shown in FIG. 9, and in some cases, it is one of the vehicle front-rear directions to the wheels. While low spring characteristics are required when an impact load is applied from the rear to the other side in the vehicle longitudinal direction, high damping characteristics are also required when a load is applied to the wheels from the front to the rear of the vehicle. It is done. In such a case, for example, the contact valve seat and the rubber valve are provided in the opening on the first fluid chamber side instead of the opening on the second fluid chamber side of the short-circuit flow path, so that the vehicle rearward to the wheel The rubber valve is elastically deformed and separated from the contact valve seat when an impact load directed from the front to the front is input, and the first fluid chamber and the second fluid chamber are communicated through a short-circuit channel to obtain a low spring characteristic. On the other hand, at the time of load input from the front to the rear of the vehicle to the wheels, the rubber valve is brought into contact with the contact valve seat to maintain the closed state of the short-circuit flow path so as to obtain a high attenuation characteristic. It is included in the technical scope of the fluid filled compliance bushing according to the present invention.

  An experiment was conducted to confirm the vibration isolation effect of the fluid-filled compliance bushing 10 having the above-described structure. The result is shown in FIG. 10 as an example. In this embodiment, a load having a frequency of 15 Hz and an amplitude of ± 2.0 mm, which corresponds to the impact load in question, is input in the opposing direction of the first fluid chamber 78 and the second fluid chamber 80 and applied. The load-deflection characteristics of the compliance bush 10 were measured. In the graph showing the load-deflection characteristic, the area in the load-deflection curve is proportional to the magnitude of the attenuation characteristic.

  In addition, when a load is applied in the direction from the first fluid chamber 78 toward the second fluid chamber 80, the load and the deflection are set so as to reach from the minimum state to the maximum state. In the load-deflection curve in FIG. 10, the curve is shown by a line that curves upward from the left diagonally lower end point to the right diagonally upper end point. In other words, the magnitude of the attenuation characteristic when a load is input in the direction from the first fluid chamber 78 to the second fluid chamber 80 is curved upwardly with a straight line connecting both end points in the longitudinal direction of the load-deflection curve. The area in the curve connecting both end points is represented by A. Furthermore, at the time of load input in the direction from the second fluid chamber 80 toward the first fluid chamber 78, the load and the deflection are set so as to reach from the maximum state to the minimum state, and the load-deflection characteristic is In the load-deflection curve in FIG. 10, the curve is indicated by a line that curves downward from the upper right end point to the lower left end point. In other words, the magnitude of the damping characteristic at the time of load input in the direction from the second fluid chamber 80 toward the first fluid chamber 78 is curved downwardly with a straight line connecting both end points in the longitudinal direction of the load-deflection curve. The area in the curve connecting both end points is represented by B.

  In addition, a fluid-filled compliance bushing (not shown) in which the first fluid chamber and the second fluid chamber are communicated with each other only by the orifice passage without providing the short-circuit channel 84 is provided. Under the same measurement conditions, the load-deflection characteristics of the fluid-filled compliance bushing were measured. The result is shown by a dashed line in FIG. 10 as a comparative example. In the comparative example, the magnitude of the damping characteristic at the time of load input in the direction from the first fluid chamber to the second fluid chamber is curved upwards with a straight line connecting both end points in the longitudinal direction of the load-deflection curve. The area in the curve connecting the two end points: represented by A ′, the magnitude of the damping characteristic at the time of load input in the direction from the second fluid chamber toward the first fluid chamber is the longitudinal direction of the load-deflection curve It is represented by an area B ′ that is curved downward and connects a straight line that connects the two end points.

  From the results shown in FIG. 10 as well, regarding the damping characteristics of the fluid-filled compliance bushing according to the comparative example, the sizes of area: A ′ and area: B ′ are substantially the same. It is recognized that the damping characteristics at the time of load input in the direction from the fluid chamber to the second fluid chamber and the damping characteristics at the time of load input in the direction from the second fluid chamber to the first fluid chamber are substantially the same. It is done.

  On the other hand, in the damping characteristic of the fluid filled compliance bushing 10 according to the present embodiment, the area: A is smaller than the area: B, so that the first fluid chamber 78 to the second fluid. The damping characteristic (spring characteristic) at the time of load input in the direction toward the chamber 80 is made smaller than the damping characteristic at the time of load input in the direction from the second fluid chamber 80 toward the first fluid chamber 78. Is recognized.

  Therefore, in the fluid-filled compliance bushing 10 according to the present invention, a low spring characteristic can be obtained when a load is applied in the direction from the first fluid chamber 78 to the second fluid chamber 80, while the second fluid Since a high damping characteristic is obtained when a load is applied in a direction from the chamber 80 toward the first fluid chamber 78, the spring characteristic or the damping characteristic is advantageously adjusted. Therefore, when an impact load is applied to the wheel from one side of the vehicle longitudinal direction to the other side, low spring characteristics are required, while at the time of normal vibration input or from the other side of the vehicle longitudinal direction to the other side. It can be suitably used for a suspension compliance bushing that has a contradictory characteristic that requires a high damping characteristic when an impact load is input.

FIG. 3 is a cross-sectional view of a fluid-filled compliance bushing for a suspension as an embodiment of the present invention, corresponding to the II cross section of FIG. 2. II-II sectional drawing of FIG. The perspective view of the integral vulcanization molding product of the main body rubber elastic body provided with the inner cylinder metal fitting and metal sleeve which constitute a part of the fluid enclosure type compliance bush. The one side view of the integral vulcanization molding product of the main body rubber elastic body. The perspective view of the 1st orifice member which comprises a part of the fluid enclosure type compliance bush. The perspective view of the 2nd orifice member which comprises a part of the fluid enclosure type compliance bush. The perspective view of the state which assembled | attached the 1st orifice member and the 2nd orifice member with respect to the integral vulcanization molded product of the main body rubber elastic body. The one side view of the state which assembled | attached the 1st orifice member and the 2nd orifice member with respect to the integral vulcanization molded product of the main body rubber elastic body. FIG. 3 is an explanatory plan view of the state in which the fluid-filled compliance bushing is assembled to the suspension mechanism of the automobile. The load-deflection diagram which shows the result measured about the damping effect in the state which employ | adopted the fluid enclosure type compliance bush as a suspension mechanism.

Explanation of symbols

10: Fluid filled compliance bushing, 12: Inner cylinder fitting, 14: Outer cylinder fitting, 16: Main rubber elastic body, 56: Rubber valve, 74: Contact valve seat, 78: First fluid chamber, 80: No. Second fluid chamber, 82: Orifice passage, 84: Short circuit flow path, 86: Lower arm, 88: Vehicle body

Claims (7)

A shaft member and an outer cylinder member arranged at a predetermined distance on the outer peripheral side of the shaft member are elastically connected to each other by a main rubber elastic body, and are attached to a vehicle body side of a suspension arm in a suspension mechanism. In the fluid-filled compliance bush for the suspension in which the input load in the vehicle longitudinal direction from the wheel is exerted in the direction perpendicular to the axis,
A first fluid chamber and a second fluid chamber, which are opposed to each other in one direction perpendicular to the axis across the shaft member and in which a relative pressure fluctuation occurs when vibration is input, are formed. An incompressible fluid is sealed in the fluid chamber and the second fluid chamber, and an orifice passage is formed to communicate the first fluid chamber and the second fluid chamber with each other. A short-circuit channel is provided between the fluid chamber and the second fluid chamber, and a one-way valve means is provided in the short-circuit channel. The first fluid from the second fluid chamber as compared to the direction of fluid flow from the first fluid chamber to the second fluid chamber generated in the short-circuit channel when an impact load toward the Greater flow resistance is exerted by the one-way valve means in the direction of fluid flow toward the chamber. Fluid-filled compliance bushing for suspension, characterized in that the.   The one-way valve means includes an abutting valve seat provided at an opening edge of the first short circuit channel to the first fluid chamber, and an elastic valve body that abuts the corresponding valve seat with pre-compression. The elastic valve element is elastically deformed when the impact load from one side in the vehicle front-rear direction to the other side is input to the wheel to open the short-circuit flow path, and the first fluid chamber And the second fluid chamber are communicated with each other through the short-circuit flow path, while the elastic valve body is in an input state of an impact load directed to the wheel from the other in the vehicle longitudinal direction to the wheel or in a normal vibration input state. 2. The suspension fluid-sealing according to claim 1, wherein the short-circuit channel is closed with a precompression contacted with an opening edge of the short-circuit channel to the first fluid chamber. Formula compliance bush.   The fluid-filled compliance bush for a suspension according to claim 1 or 2, wherein the short-circuit channel is formed independently of the orifice passage.   The orifice passage is formed across one circumferential end of the first fluid chamber and the second fluid chamber, while the first fluid chamber and the second fluid chamber The fluid-filled compliance bush for a suspension according to claim 3, wherein the short-circuit channel is formed across the other end portion in the circumferential direction.   An intermediate sleeve is arranged on the outer peripheral side of the shaft member at a predetermined distance, the shaft member and the intermediate sleeve are connected to each other by the main rubber elastic body, and the outer cylinder member is connected to the intermediate sleeve. The first pocket portion and the second pocket portion, which are fixedly fitted to the outside and are formed to open to the outer peripheral surface through the first window portion and the second window portion provided in the intermediate sleeve, are fluid-tight. The first fluid chamber and the second fluid chamber are formed by being covered, while the intermediate portion in the axial direction of the intermediate sleeve has the first fluid chamber and the second fluid chamber. A support groove extending in the circumferential direction is formed between the orifice member and an orifice member extending in the circumferential direction is fitted into the support groove, and the outer cylinder member is fitted on the outer peripheral surface of the orifice member. The orifice groove provided on the outer peripheral surface of the member Fluid-filled compliance bushing for suspension according to any one of the preceding claims orifice passage is formed 1 to 4 by being covering with the cylindrical member.   A short-circuit groove is formed on the inner peripheral surface of the orifice member, the orifice member is fitted and fixed to the support groove of the intermediate sleeve, and the short-circuit groove is covered with a bottom portion of the support groove, thereby causing the short-circuit. A flow path is formed, and the contact valve seat is provided at a circumferential end edge of the orifice member where one end of the short-circuit flow path opens, and the support groove in the intermediate sleeve The elastic valve body integrally formed with the main rubber elastic body projects from the bottom of the orifice member, and the elastic valve body is elastically deformed based on the fixing of the orifice member to the support groove. 6. The elastic valve body is brought into contact with an opening edge of one of the short-circuit channels to the fluid chamber with precompression by being in close contact with the contact valve seat. Fluid-filled type for the described suspension Compliance bush.   The suspension arm constituting the suspension mechanism has a horizontal arm portion extending in the vehicle lateral direction from the wheel side toward the vehicle body side and a vertical arm portion extending in the vehicle front-rear direction, and the vertical arm portion toward the vehicle body side. The suspension fluid enclosure according to any one of claims 1 to 6, wherein the first fluid chamber and the second fluid chamber are mounted so as to face each other in a lateral direction of the vehicle. Formula compliance bush.

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