JP2006046393A - Vibration isolator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vibration isolator capable of preventing buckling and reducing a creep amount by distributing strain on the overall outer peripheral surface of a vibration isolating base body. <P>SOLUTION: The outer peripheral surface of the vibration isolating base body 3 comprises inwardly recessed first and second circular arc parts 3a and 3b formed in circular arc shapes in cross section and first and second intermediate parts 3c and 3d connecting these circular parts to each other. The intermediate part 3c is formed in an outwardly projected circular shape in cross section and the second intermediate part 3d is formed in an inwardly recessed circular arc shape in cross section. The strain on the outer peripheral surface of the vibration isolating base body 3 can be distributed over the entire surface thereof when the vibration isolating base body 3 is deformed downward, cracking is prevented from occurring on the outer peripheral surface of the vibration isolating base body 3 by preventing the buckling from occurring. In the same way, the creep amount can be reduced by a strain distributing effect. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a liquid-filled vibration isolator.

  Various anti-vibration devices are known as anti-vibration devices that prevent the engine vibration from being transmitted to the vehicle body frame while supporting and fixing an automobile engine. For example, there are liquid-filled anti-vibration devices.

  As described in Japanese Patent Application Laid-Open No. 9-329180 and Japanese Patent Application Laid-Open No. 2003-294081, this liquid-filled vibration isolator is generally attached to a first mounting tool attached to the engine side and a vehicle body frame side. The second mounting tool is connected by a vibration-proof base made of a rubber-like elastic body. And the liquid enclosure chamber is formed between the diaphragm and the vibration isolating base by the diaphragm attached to the second fixture. The liquid sealing chamber is divided into two chambers, a main liquid chamber and a sub liquid chamber, by a partitioning means, and the main liquid chamber and the sub liquid chamber are communicated with each other by an orifice.

According to this liquid-filled vibration isolator, the vibration damping function and the vibration insulation function are achieved by the fluid flow effect between the main and sub liquid chambers by the orifice and the vibration control effect of the vibration isolating substrate.
JP-A-9-329180 (for example, FIG. 2) JP 2003-294081 (for example, FIG. 1 and the like)

  By the way, in the conventional vibration isolator, as disclosed in Patent Documents 1 and 2 described above, the outer peripheral surface shape of the vibration isolating base is concave inward as a whole in a sectional view including the axis. It was formed in an arc shape. However, in such a shape, when the engine is supported and fixed (or when a load is further applied), strain tends to concentrate on a part of the outer peripheral surface of the vibration-proof base, and buckling occurs. there were. There is also a problem that the creep amount is large. As a result, sufficient durability could not be obtained.

  The present invention has been made in order to solve the above-described problems, and can prevent the buckling and reduce the amount of creep by dispersing the strain on the outer peripheral surface of the vibration-isolating base throughout. The object is to provide a vibration device.

  In order to achieve this object, the vibration isolator according to claim 1 comprises a first attachment, a cylindrical second attachment, the second attachment and the first attachment, and rubber. An anti-vibration base made of an elastic material, and the anti-vibration base has a substantially conical section whose outer diameter on the first fixture side is smaller than the outer diameter on the second fixture side. It is formed in a trapezoidal shape and has a bottom surface that is recessed toward the first fixture side, and the outer peripheral surface of the anti-vibration base is located on the first fixture side and is recessed inwardly. A first arc portion formed in a cross-sectional arc shape, a second arc portion located on the second fixture side and formed in a concave cross-section arc shape inward, the second arc portion and the first A first intermediate portion located between the first arc portion and the second intermediate portion, the first intermediate portion connecting the first arc portion and the second intermediate portion; And the second intermediate portion connects the first intermediate portion and the second arc portion, and has an inwardly concave cross-sectional arc shape or linear shape. Is formed.

  The anti-vibration device according to claim 2 is the anti-vibration device according to claim 1, wherein radii of the first and second arc portions are Ra and Rb, and radii of the first and second intermediate portions are Rc and Rd. In this case, the radius Ra of the first arc portion is set to be equal to or smaller than the radius Rb of the second arc portion (Ra ≦ Rb), and the radius Rc of the first intermediate portion is the second radius portion. The radius is set to be approximately three times larger than the radius Rb of the arc portion (3Rb ≦ Rc), smaller than the radius Rd of the second intermediate portion (Rc <Rd), and the second intermediate portion The radius Rd is set to be approximately five times or more the radius Rb of the second arc portion (5Rb ≦ Rd), or the second intermediate portion is set linearly.

  The vibration isolator according to claim 3 is the vibration isolator according to claim 1 or 2, wherein the first fixture includes a substantially cylindrical protrusion embedded in the vibration isolator base. In the cross-sectional shape including the axis of the vibration base, a position where the side surface and the bottom surface of the projecting portion intersect is a position Px, and the first intermediate portion is connected to the first arc portion and the second intermediate portion. When the positions are P1 and P2, respectively, and the linear distances between the position Px and the positions P1 and P2 are the distances L1 and L2, respectively, the first intermediate portion has a distance L1 from the position Px. , L2 has a position P3 that is longer than at least part of the arc.

  The vibration isolator according to claim 4 is the vibration isolator according to claim 3, wherein the position Px has a height direction position along the axial center of the anti-vibration base and the second arc portion and the second fixture. It is comprised so that it may become substantially the same height position with respect to the connection position, or lower than the height position.

  The vibration isolator according to claim 5 is the vibration isolator according to any one of claims 1 to 4, wherein an inner peripheral surface of the vibration isolating base is substantially in a cross-sectional shape including an axis of the vibration isolating base. In addition to being configured in a straight line, the thickness of the anti-vibration base is gradually reduced from the first fixture side toward the second fixture side.

  The vibration isolator according to claim 6 is the vibration isolator according to any one of claims 1 to 5, wherein the first intermediate portion is configured as a circumscribed circle circumscribing the first arc portion and the second intermediate portion. Has been.

  A vibration isolator according to claim 7 is the diaphragm according to any one of claims 1 to 6, wherein the diaphragm is attached to the second fixture and forms a liquid sealed chamber with the vibration isolator base. Partitioning means for partitioning the liquid sealing chamber formed by the diaphragm into a main liquid chamber on the side of the vibration isolation base and a sub liquid chamber on the diaphragm side, and the main liquid chamber and the sub liquid chamber partitioned by the partitioning means The liquid-sealed vibration isolator is provided with an orifice that allows the liquid chamber to communicate with each other.

  According to the vibration isolator of claim 1, the first arc portion and the second arc portion of the outer peripheral surface of the vibration isolating base are connected by the first and second intermediate portions, and the first arc portion and the second arc portion are connected. The first intermediate portion located between the first intermediate portion and the second circular arc portion is formed inward while the first intermediate portion located between the first intermediate portion and the second circular arc portion is formed inwardly. It was formed in a concave cross-sectional arc shape. Thereby, since the distortion of the outer peripheral surface of the vibration-proof substrate can be uniformly distributed as a whole, it is possible to prevent the occurrence of buckling and prevent the outer peripheral surface from cracking. . Similarly, there is an effect that the amount of creep can be reduced by the strain dispersion effect. As a result, the durability can be greatly improved and the influence on the stopper clearance can be suppressed.

  According to the vibration isolator according to claim 2, in addition to the effect of the vibration isolator according to claim 1, the vibration isolator base is formed with the first arc portion with the smallest diameter portion. Since the radius Ra is set to be equal to or less than the radius Rb of the second arc portion, there is an effect that the region of the minimum diameter portion can be prevented from becoming too large. As a result, the strain on the outer surface of the vibration-proof substrate is dispersed throughout to suppress the occurrence of buckling, and the amount of creep can be reduced, so that the durability can be greatly improved, and the stopper The influence on the clearance can be suppressed.

  Further, since the radii Rc and Rd of the first and second intermediate portions are set to approximately 3 times and approximately 5 times or more of the radius Rb of the second arc portion, respectively, the unevenness of the outer surface of the vibration isolating base becomes large. This has the effect that the strain on the outer surface of the vibration-proof substrate can be dispersed more uniformly as a whole. As a result, due to the strain dispersion effect, as described above, it is possible to suppress the occurrence of buckling and to reduce the creep amount, thereby significantly improving the durability and suppressing the influence on the stopper clearance.

  That is, since the radius Rc of the first intermediate portion is set to be approximately three times or larger than the radius Rb of the second arc portion, the first intermediate portion is excessively raised from the outer surface of the vibration isolating base, There is an effect that it is possible to suppress the concentration of strain in the region (the first arc portion or the second intermediate portion).

  On the other hand, since the radius Rd of the second intermediate portion is set to a size that is approximately five times greater than the radius Rb of the second arc portion, the second intermediate portion is excessively depressed from the outer surface of the vibration-isolating base. There is an effect that the strain can be suppressed from concentrating on the (second intermediate portion).

  According to the vibration isolator according to claim 3, in addition to the effect of the vibration isolator according to claim 1 or 2, since the first fixture has the protrusion embedded in the vibration isolator base, There is an effect that the ratio of the spring constant in the direction perpendicular to the axial center to the spring constant in the core direction can be increased.

  Here, when the projecting portion is provided in this way, the strain tends to concentrate on a part of the outer peripheral portion due to the effect of the projecting portion. According to the present invention, the distance from the position Px is the distance L1. , L2 is configured so that the first intermediate portion has at least a part of the arc shape at a position P3 that is longer than L2, so that even if a protrusion is provided, the distortion of the outer peripheral surface of the vibration-proof base is made uniform throughout. There is an effect that it can be dispersed. As a result, the occurrence of buckling can be suppressed and the amount of creep can be reduced, so that the durability can be significantly improved and the influence on the stopper clearance can be suppressed.

  According to the vibration isolator of claim 4, in addition to the effect of the vibration isolator according to claim 3, the position Px (that is, the position where the side surface and the bottom surface of the projecting portion intersect) has a height direction position. Since it is configured to be substantially the same height position or lower than the height position with respect to the connection position of the second arcuate portion and the second mounting tool, There is an effect that the ratio of the spring constant in the direction perpendicular to the center can be increased.

  According to the vibration isolator according to claim 5, in addition to the effect of the vibration isolator according to any one of claims 1 to 4, the inner peripheral surface of the vibration isolator base is formed in a substantially linear cross section. There is an effect that the manufacturing process of the mold can be simplified and the product cost of the vibration isolator as a whole can be reduced accordingly. In addition, since the thickness dimension of the vibration-proof base is gradually reduced from the first fixture side to the second fixture side, it is easy to move in the axial direction, and the ratio of the spring constant in the axial direction is set. There is an effect that the spring constant in the direction perpendicular to the axis can be reduced.

  According to the vibration isolator according to claim 6, in addition to the effect exhibited by the vibration isolator according to any one of claims 1 to 5, the first intermediate portion is circumscribed to the first arc portion and the second intermediate portion. Since it was comprised as a circle | round | yen, there exists an effect that the connection part of each of those site | parts can be formed smoothly, and it can suppress that an acute angle site | part is formed in the outer surface of a vibration proof base. As a result, the strain on the outer peripheral surface of the anti-vibration substrate can be uniformly distributed as a whole, which suppresses the occurrence of buckling and reduces the amount of creep, greatly improving durability and affecting the stopper clearance. Can be suppressed.

  According to the vibration isolator according to claim 7, in addition to the effect exhibited by the vibration isolator according to any one of claims 1 to 6, it is configured as a liquid-filled vibration isolator. In addition to the vibration insulation function due to the above, there is an effect that the vibration damping function can be exhibited by the fluid flow effect between the main and sub liquid chambers due to the orifice.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a cross-sectional view of a liquid-filled vibration isolator 100 according to an embodiment of the present invention.

  The liquid-filled vibration isolator 100 is a vibration isolator for supporting and fixing an automobile engine so that the engine vibration is not transmitted to the vehicle body frame, and is attached to the engine side as shown in FIG. The first mounting bracket 1, the cylindrical second mounting bracket 2, and the anti-vibration base 3 that connects both the brackets 1 and 2 and is made of a rubber-like elastic body are mainly provided. .

  As shown in FIG. 1, the first mounting bracket 1 is formed of an aluminum alloy in a substantially cylindrical shape, and a female thread portion 11 is directed downward (downward in FIG. 1) on the upper end surface (upper side surface in FIG. 1). It is recessed. Further, a flange-like stoppered portion 12 is formed to project outward in the radial direction at a substantially intermediate portion in the longitudinal direction (the vertical direction in FIG. 1) of the first mounting bracket 1.

  Here, the first mounting bracket 1 has a protruding portion 13 below the stopper portion 12 (lower side in FIG. 1), and the protruding portion 13 is embedded in the vibration isolating base 3 as shown in FIG. ing. Thereby, it is possible to increase the ratio of the spring constant in the direction perpendicular to the axis O (left and right direction in FIG. 1) to the spring constant in the axis O direction (up and down direction in FIG. 1).

  Note that the bottom surface of the protrusion 13 (position Px described later, see FIG. 2) has a height direction (vertical direction in FIG. 1) along the axis O at least the second arc portion 3b (see FIG. 2) described later and the second arc portion 3b (see FIG. 2). 2 It is preferable that the height position is substantially equal to the connection position with the mounting bracket 2 or below (lower side in FIG. 1).

  As a result, when the engine is supported and fixed, the protrusion 13 and the second mounting bracket 2 (large-diameter cylindrical portion 2a) overlap each other when viewed in a direction perpendicular to the axis O direction. This is because the ratio of the spring constant in the direction perpendicular to the axis O can be further increased.

  As shown in FIG. 1, the second mounting bracket 2 is formed in a cylindrical shape having upper and lower ends (upper and lower sides in FIG. 1) opened from a steel material. The second mounting bracket 2 has a step, and the upper side (upper side in FIG. 1) of the step is a large-diameter cylindrical portion 2a, and the lower side (lower side in FIG. 1) is a small-diameter cylinder. Part 2b.

  As shown in FIG. 1, the anti-vibration base 3 is formed in a substantially frustoconical cross section symmetrical from the rubber-like elastic body around the axis O and toward the first mounting bracket 1 side (upper side in FIG. 1). It has a recessed bottom surface and is vulcanized and bonded between the lower end side of the first mounting bracket 1 (lower side in FIG. 1) and the inner peripheral portion of the upper end of the second mounting bracket 2 (upper side in FIG. 1).

  As shown in FIG. 1, a stopper rubber portion 31 covering the stopper portion 12 of the first mounting bracket 1 is connected to the upper end portion (upper side in FIG. 1) of the vibration isolating base 3. Is configured to obtain a stopper action at the time of large displacement by abutting against a stopper fitting 4 described later.

  That is, when the liquid-filled vibration isolator 100 supports and fixes the engine, the first mounting bracket 1 is moved to the second mounting bracket 2 side by the amount of displacement corresponding to the shared load and the static spring constant in the direction of the axis O. By displacing (lower side in FIG. 1), a predetermined amount of stopper clearance on the rebound side is formed between the upper surface (upper side surface in FIG. 1) of the stopper rubber portion 31 and the lower surface of the stopper fitting 4 (lower side surface in FIG. 1). Is done.

  As shown in FIG. 1, a rubber film 32 covering the inner peripheral surface of the second mounting bracket 2 is connected to the lower end portion (lower side in FIG. 1) of the vibration isolating base 3. The orifice forming walls 81 and 82 of the orifice member 8 to be described later and the mounting bracket 51 of the diaphragm 5 are in close contact with each other.

  As shown in FIG. 1, a stopper fitting 4 is press fitted into the upper end portion (large diameter cylindrical portion 2 a) of the second mounting fitting 2. As described above, the stopper fitting 4 is a member for restricting the displacement of the stopper rubber portion 31 and obtaining a stopper action, and is configured in a substantially cup shape from a steel material.

  As shown in FIG. 1, a liquid draining hole 41 is formed in the side surface of the stopper fitting 4. The drain hole 41 is a discharge hole for discharging the liquid stored in the inner peripheral space of the stopper fitting 4, and is a height that substantially coincides with the upper edge (the upper side in FIG. 1) of the second mounting fitting 2. It is open. When liquid or the like is stored in the inner peripheral space of the stopper fitting 4 during the assembly process or traveling of the liquid-filled vibration isolator 100, the liquid or the like is discharged to the outside through the liquid drain hole 41. The

  A plurality of mounting brackets (not shown) are welded and fixed to the outer peripheral surface of the stopper metal 4, and the above-described second mounting metal 2 is attached to the vehicle body via the mounting bracket and the stopper metal 4. It has been. Further, a stopper cover 34 that functions as a bound side stopper is laminated on the upper surface (upper side surface in FIG. 1) of the stopper fitting 4. When the engine is supported and fixed, the upper surface (upper side surface in FIG. 1). ) And an engine side member (not shown), a bound side stopper clearance is formed by a predetermined amount.

  As shown in FIG. 1, the diaphragm 5 is formed from a rubber-like elastic body into a rubber film shape having a partial spherical shape, and the lower end of the second mounting bracket 2 (small-diameter cylindrical portion 2 b) (lower side in FIG. 1). ) Is attached. As a result, a liquid sealing chamber 6 is formed between the upper surface side of the diaphragm 5 and the lower surface side of the vibration isolation base 3.

  The liquid enclosure 6 is filled with an antifreeze liquid (not shown) such as ethylene glycol. Further, as shown in FIG. 1, the liquid sealing chamber 6 includes a main liquid chamber 6A on the side of the vibration isolating base 3 (upper side in FIG. 1) and a diaphragm by a partition member 7 (orifice member 8 and elastic partition film 9) described later. It is divided into two chambers, a sub liquid chamber 6B on the 5 side (lower side in FIG. 1).

  The diaphragm 5 is vulcanized and bonded to a donut-shaped mounting bracket 51 as viewed from above, and the lower end of the second mounting bracket 2 (the lower side in FIG. 1) is attached via the mounting bracket 51 as shown in FIG. ) Is attached.

  As shown in FIG. 1, the partition member 7 divides the liquid sealing chamber 6 into a main liquid chamber 6A and a sub liquid chamber 6B, an orifice member 8 configured from a resin material in a substantially cylindrical shape, and a rubber-like member And an elastic partition film 9 formed in an approximately disc shape from an elastic body. The elastic partition membrane 9 is disposed at a position that divides the main and sub liquid chambers 6A and 6B, and the outer peripheral portion thereof is vulcanized and bonded to the orifice member 8.

  As a result, when a relatively small amplitude is input, the elastic partition film 9 is reciprocally displaced, so that the hydraulic pressure difference between the liquid sealing chambers 6 (main and auxiliary liquid chambers 6A and 6B) is relieved, Low dynamic spring characteristics can be obtained.

  As shown in FIG. 1, orifice forming walls 81 and 82 are formed on the upper and lower ends (upper and lower sides in FIG. 1) of the orifice member 8 so as to project outward in the radial direction. An orifice 20 is formed between the opposing surfaces of the walls 81 and 82 (that is, between the outer peripheral surface side of the orifice member 8 and the inner peripheral surface side (rubber film 32) of the second mounting member 2). The orifice 20 is an orifice channel that communicates the main liquid chamber 6A and the sub liquid chamber 6B.

  The orifice 20 communicates with the main liquid chamber 6A through a notch (not shown) formed in the upper (the upper side in FIG. 1) orifice forming wall 81, while the side surface of the orifice member 8 The sub liquid chamber 6B communicates with the auxiliary liquid chamber 6B through an opening (not shown) formed therethrough.

  Here, the assembly of the liquid-filled vibration isolator 100 is performed by first fitting the partition member 7 and the diaphragm 5 in order from the lower end side (lower side in FIG. 1) of the second mounting bracket 2 and then the second mounting bracket. This is done by subjecting the entire two small-diameter cylindrical portions 2b to diameter reduction processing (drawing processing) in the radial direction (left-right direction in FIG. 1).

  This drawing process is performed using a drawing die having a plurality of movable die blades. Specifically, the plurality of drawing operations are performed so as to surround the entire outer peripheral surface of the small-diameter cylindrical portion 2b of the second mounting bracket 2. In addition to arranging the die blades and moving the die blades toward the center, the entire small diameter cylindrical portion 2b is uniformly reduced in the radial direction.

  As a result, as shown in FIG. 1, the partition member 7 (orifice member 8) has a partition body receiving portion 33 provided on the vibration isolation base 3 and the diaphragm 5, so that the axial direction ( (Fixed in the vertical direction in FIG. 1). The partition body receiving portion 33 is formed as a step portion at a plurality of locations (or the entire circumference) on the lower surface side of the vibration isolating base 3, and the upper end surface (upper side surface in FIG. 1) of the orifice member 8 is formed by the step portion. Take it.

  Here, in this assembled state, the partition body receiving portion 33 is compressed and deformed, and the elastic restoring force of the partition body receiving portion 33 is applied to the upper end surface of the partition member 7 as the holding force of the partition member 7. Yes. As a result, even when a large amplitude or a high frequency amplitude is input, the partition member 7 is firmly and stably sandwiched and fixed, and the influence on the dynamic characteristics due to the positional deviation, resonance, etc. of each member. Can be avoided.

  Next, with reference to FIG. 2, the detailed structure of the vibration-proof base 3 will be described. FIG. 2 is a partially enlarged cross-sectional view of the liquid-filled vibration isolator 100 and shows a cross-sectional shape (a cross-sectional shape including the axis O) in an unloaded state (that is, a state before the engine is supported and fixed). .

  In FIG. 2, in order to facilitate understanding of the shape of the anti-vibration base 3, hatching (diagonal lines) of the anti-vibration base 3 is omitted, and extension lines along the arc shapes of the portions 3 a to 3 d are omitted. Is illustrated using fine lines.

  As shown in FIG. 2, the outer peripheral surface of the vibration isolating base 3 is located on the first fixture 1 side (upper side in FIG. 1), is connected to the stopper rubber portion 31, and has an inwardly concave cross-sectional arc shape. The first arc portion 3a to be formed and the second mounting fixture 2 side (the lower side in FIG. 1) are connected to the upper end surface of the second mounting bracket 2 and have an inwardly concave cross-sectional arc shape. The second arc portion 3b is formed, and the first and second intermediate portions 3c and 3d are located between the second arc portion 3b and the first arc portion 3a.

  As shown in FIG. 2, the first intermediate portion 3c connects the first arc portion 3a and the second intermediate portion 3d and is formed in an outwardly convex cross-sectional arc shape, while the second intermediate portion 3d connects the 1st intermediate part 3c and the 2nd circular arc part 3b, and is formed in the cross-section circular arc shape inwardly concave.

  As a result, when the vibration isolating base 3 is bent downward (lower side in FIG. 1) by the share of the engine load (or more), the strain on the outer peripheral surface of the vibration isolating base 3 is dispersed throughout. Therefore, the occurrence of buckling can be prevented, and the occurrence of cracks on the outer peripheral surface of the vibration-isolating base 3 can be suppressed. Similarly, the amount of creep can be reduced by the strain dispersion effect.

  As a result, the durability can be greatly improved, and the influence on the stopper clearance (for example, the amount of stopper clearance on the rebound side becomes too large) can be suppressed, and the occurrence of hitting sound during driving can be prevented. Can be suppressed.

  Here, the radius Ra of the first arc portion 3a is preferably set to a size (Ra ≦ Rb) that is equal to or less than the radius Rb of the second arc portion 3b. In other words, the vibration isolating base 3 is formed with the minimum diameter portion at the first arc portion 3a. However, if the radius Ra of the first arc portion 3a is excessively increased, the area of the minimum diameter portion occupying the whole becomes large. This is because the strain at the time of bending deformation concentrates on the (first arc portion 3a).

  Further, the radius Rc of the first intermediate portion 3b is set to be approximately three times larger than the radius Rb of the second arc portion 3b (3Rb ≦ Rc), and is smaller than the radius Rd of the second intermediate portion 3b. (Rc <Rd) Further, it is preferable that the radius Rd of the second intermediate portion is set to be approximately five times or more the radius Rb of the second arc portion 3b (5Rb ≦ Rd).

  If the radii Rc and Rd of the first and second intermediate portions 3c and 3d are too small (for example, equivalent to the radius Rb of the second arc portion 3b), the unevenness of the outer surface of the vibration isolating base 3 becomes too large, This is because the strain on the outer surface of the vibration-proof substrate 3 cannot be properly dispersed throughout.

  That is, if the radius Rc of the first intermediate portion 3c is set to a radius smaller than about three times the radius Rb of the second arc portion 3b, the first intermediate portion 3c rises too much from the outer surface of the vibration-isolating base 3. The strain concentrates on other regions (first arc portion 3a and second intermediate portion 3d).

  On the other hand, if the radius Rd of the second intermediate portion 3d is set to a radius smaller than about five times the radius Rb of the second arc portion 3b, the second intermediate portion is too depressed from the outer surface of the vibration-isolating base 3. The strain is concentrated in such a region (second intermediate portion).

  In addition, as for the 1st and 2nd intermediate parts 3c and 3d, it is more preferable to set ratio Rc: Rd of the radii Rc and Rd in the range of 3: 4.5 to 3: 5.5. Is to set the ratio Rc: Rd to a value in the vicinity of 3: 5. This is because, when the vibration-proof base 3 is bent and deformed, the strain on the outer surface can be uniformly distributed as a whole.

  Here, as shown in FIG. 2, in the cross-sectional shape including the axis of the vibration isolator base 3, the position where the side surface and the bottom surface of the projecting portion 13 intersect is a position Px, and the first intermediate portion 3 c is the first arc portion. When the connection positions connected to 3a and the second intermediate portion 3d are positions P1 and P2, respectively, and the linear distances between the position Px and the positions P1 and P2 are distances L1 and L2, respectively, the first It is preferable that the intermediate part 3c is configured to have a position P3 where the distance L3 from the position Px is longer than the distances L1 and L2 in at least a part of the arc.

  As described above, when the first fixture 1 includes the substantially cylindrical protrusion 13 embedded in the vibration isolation base 3, the outer periphery of the vibration isolation base 3 is affected by the protrusion. This is because the distortion of the part tends to concentrate on a part, and this is eliminated. That is, by defining the first intermediate portion 3d as described above, even when the protruding portion 13 is provided, the strain on the outer peripheral surface of the antivibration base 3 can be uniformly distributed as a whole.

  The first intermediate portion 3c is most preferably configured such that the distance L3 from the position Px is longer than the distances L1 and L2 in the entire arc shape. In order to increase the spring constant in the direction perpendicular to the axis O, even when the bottom surface (that is, the position Px) of the projecting portion 13 is extended downward (lower side in FIG. 2), This is because the strain can be dispersed more uniformly throughout.

  Here, each part 3a-3d which comprises the outer peripheral surface of the anti-vibration base | substrate 3 is comprised as an arc circumscribed (or inscribed) with respect to the circular arc of the other parts 3a-3d, as shown in FIG. Preferably it is. If each arc is configured to intersect with another arc, the connecting portion between each part 3a to 3d cannot be formed smoothly, and an acute part is formed on the outer surface of the vibration-isolating base 3. This is because the strain tends to concentrate on the sharp part and the like, and the strain cannot be dispersed throughout.

  Further, as shown in FIG. 2, the first intermediate portion 3c is located at the outermost position on the extension line along the arc shape of the first intermediate portion 3c (that is, the position where the separation distance from the axis O becomes maximum). Is a position Py, the distance Lxy (not shown) from the position Px to the position Py in the direction perpendicular to the axis O (the left-right direction in FIG. 2) is the large diameter of the second mounting bracket 2 from the position Px. It is preferable that the distance Lxa (not shown) to the inner peripheral surface of the cylindrical portion 2a is configured to be a value within a range of approximately 35% to approximately 65% (0.35Lxa ≦ Lxy ≦ 0.65Lxa). . The range is more preferably 0.45Lxa ≦ Lxy ≦ 0.55Lxa.

  If the distance Lxy is too short, the region of the first intermediate portion 3c is reduced, and it becomes difficult to obtain the effect of raising the first intermediate portion 3c from the outer peripheral portion of the vibration-isolating base 3. While it becomes impossible to disperse the strain as a whole, if the distance Lxy is too long, the first intermediate portion 3c rises excessively from the outer surface of the vibration-isolating base 3, and other regions (the first arc portion 3a and the second arc portion 2). This is because the strain concentrates on the intermediate part 3d).

  As shown in FIG. 2, the inner peripheral surface of the vibration isolating base 3 is configured to be substantially linear in the cross-sectional shape including the axis O, and the thickness dimension of the vibration isolating base 3 is on the first fixture 1 side. It is comprised so that it may become thin gradually toward the 2nd fixture 2 side. This facilitates movement in the direction of the axis O (the vertical direction in FIG. 2), and the ratio of the spring constant in the direction of the axis O can be reduced with respect to the spring constant in the direction perpendicular to the axis O.

  The present invention has been described based on the embodiments. However, the present invention is not limited to the above embodiments, and various modifications can be easily made without departing from the spirit of the present invention. It can be guessed.

  For example, in the above embodiment, the second intermediate portion 3d is formed in an inwardly concave cross-sectional arc shape, but is not necessarily limited thereto, and may be formed in a straight line shape. Here, with reference to FIG. 3, the liquid filled type vibration isolator 200 in which the second intermediate portion 203d is formed in a straight line will be described. In addition, the same code | symbol is attached | subjected to the part same as the said Example, and the description is abbreviate | omitted.

  As shown in FIG. 3, the outer peripheral surface of the vibration isolating base 3 includes first and second arc portions 3a and 3b and a first intermediate portion 3c, as in the case of the above embodiment, and includes a first intermediate portion. The second intermediate portion 203d that connects 3c and the second arc portion 3b is formed in a straight line.

  Even in such a configuration, if the vibration isolating base 3 is bent downward (lower side in FIG. 1) by the share of the engine load (or more), the distortion of the outer peripheral surface of the vibration isolating base 3 Therefore, the occurrence of buckling can be prevented, and the occurrence of cracks on the outer peripheral surface of the vibration-isolating base 3 can be suppressed. Similarly, the amount of creep can be reduced by the strain dispersion effect.

  The second intermediate portion 203d is preferably configured as a tangent line circumscribing the first intermediate portion 3c and the second arc portion 3b. If the straight line of the second intermediate part 203d intersects with the arcs of the first intermediate part 3c and the second arc part 3b, the connecting parts cannot be formed smoothly, and the vibration isolating substrate This is because an acute angle portion is formed on the outer surface of No. 3, and the strain tends to concentrate on the acute angle portion or the like, and the strain cannot be dispersed throughout.

  In the above embodiment, the case where the protrusion 13 is formed on the first mounting bracket 1 has been described as an example. However, the present invention is not necessarily limited to this, and the first mounting bracket 1 is configured by omitting the protrusion 13. Of course it is possible to do.

1 is a cross-sectional view of a liquid-filled vibration isolator in one embodiment of the present invention. It is a partial expanded sectional view of a liquid enclosure type vibration isolator. It is a partial expanded sectional view of the liquid enclosure type vibration isolator in a modification.

Explanation of symbols

100,200 Liquid-filled vibration isolator 1 First mounting bracket (first mounting bracket)
13 Protrusion 2 Second mounting bracket (second mounting bracket)
3 Anti-vibration base 3a First arc portion 3b Second arc portion 3c First intermediate portion 3d Second intermediate portion 5 Diaphragm 6 Liquid enclosure 6A Main liquid chamber 6B Sub liquid chamber 7 Partition member (partition means)
8 Orifice member (part of partitioning means)
9 Elastic partition membrane (part of partitioning means)
20 Orifice Ra Radius Rb of the first arc portion Radius Rc of the second arc portion Radius Rd of the first intermediate portion Radius Pd of the second intermediate portion P1 Position P1 where the side surface and bottom surface of the projecting portion intersect the first intermediate portion and the first Connection position P2 with arc portion Connection position P3 between first intermediate portion and second intermediate portion Position L1 where distance from position Px is longer than distances L1 and L2 Linear distance L2 between position Px and position P1 Linear distance O between Px and position P2

Claims (7)

In a vibration isolator comprising a first fixture, a cylindrical second fixture, a vibration isolator base that connects the second fixture and the first fixture and is made of a rubber-like elastic material. ,
The anti-vibration base is formed in a substantially truncated cone shape with an outer diameter on the first fixture side smaller than an outer diameter on the second fixture side, and is recessed toward the first fixture side. Having a bottom surface,
An outer peripheral surface of the anti-vibration base is located on the first fixture side, is located on the second fixture side, with a first arc portion formed in an inwardly concave cross-sectional arc shape, and inwardly. A second arc portion formed in a concave arcuate cross section, and first and second intermediate portions positioned between the second arc portion and the first arc portion,
The first intermediate part connects the first arc part and the second intermediate part, and is formed in an outwardly convex cross-sectional arc shape,
The second intermediate portion connects the first intermediate portion and the second arc portion, and is formed in an inwardly concave cross-sectional arc shape or linear shape. When the radii of the first and second arc portions are Ra and Rb, and the radii of the first and second intermediate portions are Rc and Rd,
The radius Ra of the first arc portion is set to be equal to or smaller than the radius Rb of the second arc portion (Ra ≦ Rb),
In addition, the radius Rc of the first intermediate portion is set to be approximately three times larger than the radius Rb of the second arc portion (3Rb ≦ Rc), and is smaller than the radius Rd of the second intermediate portion. (Rc <Rd),
In addition, the radius Rd of the second intermediate portion is set to a size that is approximately five times or more the radius Rb of the second arc portion (5Rb ≦ Rd), or the second intermediate portion is set to be linear. The anti-vibration device according to claim 1. The first fixture includes a substantially columnar protrusion embedded in the vibration isolation base,
In the cross-sectional shape including the shaft center of the vibration isolator base, a position where the side surface and the bottom surface of the projecting portion intersect is a position Px, and the first intermediate portion is connected to the first arc portion and the second intermediate portion. When the connection positions are P1 and P2, respectively, and the linear distances between the position Px and the positions P1 and P2 are distances L1 and L2, respectively.
The first intermediate portion is configured to have a position P3 at least a part of the arc of which the distance from the position Px is longer than the distances L1 and L2. The vibration isolator as described.   In the position Px, the height direction position along the axis of the vibration-proof base is substantially equal to the height position with respect to the connection position between the second arc portion and the second fixture, or higher than the height position. The anti-vibration device according to claim 3, wherein the anti-vibration device is configured to be low.   The inner peripheral surface of the vibration isolating base is substantially linear in the cross-sectional shape including the axis of the vibration isolating base, and the thickness dimension of the vibration isolating base is the second fixture side from the first fixture side. The vibration isolator according to any one of claims 1 to 4, wherein the vibration isolator is configured so as to gradually become thinner toward the fixture side.   The vibration isolator according to any one of claims 1 to 5, wherein the first intermediate portion is configured as a circumscribed circle circumscribing the first arc portion and the second intermediate portion.   A diaphragm which is attached to the second fixture and forms a liquid sealing chamber between the vibration isolating base and the liquid sealing chamber formed by the diaphragm is divided into a main liquid chamber on the side of the vibration isolating base and the diaphragm side. Characterized in that it is configured as a liquid-filled vibration isolator comprising partition means for partitioning into the secondary liquid chamber and an orifice for communicating the main liquid chamber and the secondary liquid chamber that are partitioned by the partition means. The vibration isolator according to any one of claims 1 to 7.

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