Vibration isolation device

Abstract

To provide a vibration absorbing device capable of improving durability of a vibration absorbing base.SOLUTION: A vibration absorbing base 13 is arranged via a gas chamber 24 at a first side in an axial line C direction to a restriction part 20 mounted on an inner peripheral surface of a first member 11 or a film part 14. Due to that the restriction part 20 projects to the inside in a radial direction than a corner part 19 of an inclined part 17 and a raised part 16 in the vibration absorbing base 13, the deformation of the vibration absorbing base 13 can be restricted by abutting the vibration absorbing base 13 on the restriction part 20 when a second member 12 is deviated to the first member 11 at least to a second side in the axial line C direction. With this, the vicinity of the corner part 19 of the vibration absorbing base 13 can be hardly buckled at the time of the deviation of the second member 12 to the second side so as to hardly generate cracks caused by buckling in the vibration absorbing base 13, and improve durability of the vibration absorbing base 13.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a vibration isolation device, and particularly to a vibration isolation device capable of improving the durability of a vibration isolation base body.

Background Art

[0002] Patent Document 1 discloses a vibration isolation device including a cylindrical first member, a second member disposed offset to the first side in the axial direction of the first member on the inner peripheral side of the first member, and an elastic vibration isolation base body connecting the inner peripheral surface of the first member and the second member. Among these, the surface on the second side opposite to the first side in the axial direction of this vibration isolation base body includes a standing portion extending in the axial direction and an inclined portion inclined toward the first side as it goes from the standing portion toward the inner side in the radial direction.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the conventional technology, when the second member is displaced at least to the second side with respect to the first member, at least a part of the inclined portion is compressed, and the vibration isolation base body is likely to buckle in the vicinity of the corner between the inclined portion and the standing portion. Due to the repetition of this buckling, cracks are likely to occur at the corner, so there is a problem that the durability of the vibration isolation base body decreases.

[0005] The present invention has been made to solve the above - mentioned problems, and an object thereof is to provide a vibration isolation device capable of improving the durability of a vibration isolation base body.

Means for Solving the Problems

[0006] To achieve this objective, the vibration isolation device of the present invention comprises: a cylindrical first member surrounding an axis; a second member disposed on the inner circumference side of the first member; an elastic vibration isolation base connecting the inner surface of the first member and the second member; a restricting portion attached to the inner surface of the first member or the membrane portion of the vibration isolation base covering the inner surface of the first member, which restricts the deformation of the vibration isolation base; and a gas chamber in which a gas is contained, with the first side wall surface in the axial direction formed by the vibration isolation base and the second side wall surface opposite to the first side in the axial direction formed by the restricting portion. The second side surface of the vibration-damping base comprises a contact portion extending radially inward from the inner circumferential surface of the first member and contacting the restricting portion, an upright portion extending toward the first side from the inner edge of the contact portion, and an inclined portion that slopes toward the first side as it extends radially inward from the upright portion, the restricting portion protruding radially inward from the corner between the inclined portion and the upright portion, a through hole formed in the restricting portion that penetrates in the axial direction, the gas chamber being opened to the atmosphere through the through hole, and the inclined portion having a conical surface shape with an inner circumferential edge. The inner diameter of the through hole is larger than the diameter of the inner periphery of the inclined portion. The edge of the through-hole is located radially outward from the inner peripheral edge of the inclined portion, and the inner edge of the restricting portion that forms the through-hole is smoothly curved toward the second side. [Effects of the Invention]

[0007] According to the vibration isolation device described in claim 1, a vibration isolation base is positioned on the first axial side of a regulating portion attached to the inner circumferential surface or membrane portion of the first member, via a gas chamber. Since the regulating portion protrudes radially inward from the corner between the inclined portion and the upright portion of the vibration isolation base, when the second member is displaced at least to the second axial side relative to the first member, the vibration isolation base can be pressed against the regulating portion to restrict the deformation of the vibration isolation base. As a result, buckling near the corner of the vibration isolation base is less likely to occur when the second member is displaced to the second side, making it less likely for cracks to occur in the vibration isolation base due to buckling, and improving the durability of the vibration isolation base. The gas chamber is opened to the atmosphere through a through-hole that penetrates the regulating section axially. Therefore, when the volume of the gas chamber changes due to the relative displacement between the first and second members, gas flows in and out through the through-hole. This suppresses the rise in internal pressure of the gas chamber. Furthermore, since the rate of gas inflow and outflow can be easily adjusted by adjusting the size and number of through-holes, the spring characteristics of the gas chamber can be easily adjusted. The inner diameter of the through hole is larger than the diameter of the inner periphery of the inclined portion. Since the edge of the through-hole is located radially outward from the inner edge of the conical inclined portion, the velocity of gas flowing in and out through the through-hole can be increased, and the spring characteristics of the air spring formed by the gas chamber can have almost no effect on the spring characteristics of the vibration-damping base. Furthermore, since the inner edge of the regulating portion that forms the through-hole curves smoothly toward the second side, it is difficult for the deformed vibration-damping base to become embedded in the inner edge of the regulating portion (the edge of the through-hole), thereby improving the durability of the vibration-damping base.

[0008] The vibration isolation device according to claim 2 provides the following effects in addition to those of the vibration isolation device according to claim 1. The regulating portion is provided with a protrusion that extends toward the inclined portion. This makes it easier to bring the vibration isolation base into contact with the protrusion of the regulating portion earlier when the second member is displaced toward the second side relative to the first member, compared to the case where there is no protrusion. As a result, buckling near the corners can be made less likely, and the durability of the vibration isolation base can be further improved.

[0009] The vibration isolation device according to claim 3 provides the following effects in addition to those of the vibration isolation device according to claim 2. The shape of the protrusions follows the vertical, corner, and inclined portions in the unloaded state, making it easier to bring the vibration isolation base into surface contact with the protrusions when the second member is displaced to the second side relative to the first member. This suppresses the concentration of strain on a part of the vibration isolation base during deformation, thereby further improving the durability of the vibration isolation base.

[0010] The vibration isolation device according to claim 4 provides the following effects in addition to the effects of the vibration isolation device according to any one of claims 1 to 3. The extension portion extending from the radial outer edge of the restricting portion toward the second side is attached to the inner circumferential surface or membrane portion of the first member. This makes it difficult for the restricting portion to shift axially or otherwise relative to the inner circumferential surface or membrane portion of the first member. Therefore, the displacement of the vibration isolation base can be more easily restricted by the restricting portion, making it less likely for the vicinity of the corners to buckle, and thus the durability of the vibration isolation base can be further improved.

[0011]

[0012] The vibration isolation device according to claim 5 provides the following effects in addition to the effects of the vibration isolation device according to any one of claims 1 to 4. The restricting portion includes a recess that is recessed toward the second side at a position radially inward from the corner. The restricting portion radially outward from the recess restricts deformation of the vibration isolation base near the corner, while the recess allows deformation of the portion of the vibration isolation base away from the corner. This makes it difficult for the area near the corner to buckle, while improving the vibration isolation performance of the vibration isolation base. [Brief explanation of the drawing]

[0013] [Figure 1] This is a cross-sectional view of the vibration isolation device in the first embodiment. [Figure 2] This is a cross-sectional view of the vibration isolation device in the second embodiment. [Figure 3] This is a cross-sectional view of the vibration isolation device in the third embodiment. [Figure 4] This is a cross-sectional view of the vibration isolation device in the fourth embodiment. [Modes for carrying out the invention]

[0014] Preferred embodiments will be described below with reference to the attached drawings. Figure 1 is a cross-sectional view of the vibration damping device 10 in the first embodiment. In this embodiment, the engine mount will be used as an example of the application target of the vibration damping device 10. Figure 1 also shows the vibration damping device 10 before installation on the vehicle, in an unloaded state where no load is applied from the engine.

[0015] The vibration isolation device 10 includes a cylindrical first member 11 attached to the vehicle body side, a second member 12 attached to the engine side, a vibration isolation base 13 made of an elastic body that connects the first member 11 and the second member 12, a restricting portion 20 that restricts deformation of the vibration isolation base 13, and a gas chamber 24 formed between the vibration isolation base 13 and the restricting portion 20 and containing a gas (for example, air).

[0016] The first member 11 is a cylindrical member surrounding an axis C as a central axis, and is mainly formed of a metal such as steel. Note that the cross-sectional view of the vibration isolation device 10 in FIG. 1 is an axial cross-sectional view including this axis C. Also, for the sake of simplifying the explanation, the upper side (the first side) of the vibration isolation device 10 in the axial direction of the axis C on the upper side of the paper surface of FIG. 1 is defined as the upper side of the vibration isolation device 10, and the lower side (the second side) of the paper surface of FIG. 1 is defined as the lower side of the vibration isolation device 10 for explanation, but these upper and lower sides do not necessarily coincide with the upper and lower sides of the vehicle to which the vibration isolation device 10 is attached.

[0017] The first member 11 includes a large-diameter portion 11a on the upper end side, a reduced-diameter portion 11b that is continuous with the lower end of the large-diameter portion 11a and whose inner and outer diameters gradually decrease downward, and a small-diameter portion 11c that is continuous with the lower end of the reduced-diameter portion 11b and has inner and outer diameters smaller than those of the large-diameter portion 11a. For example, the first member 11 is attached to the vehicle body side by inserting the first member 11 into a cylindrical bracket provided on the vehicle body side.

[0018] The second member 12 is a boss fitting formed of a metal such as steel or an aluminum alloy, and a flange portion projects radially from the upper end of the cylindrical portion. The second member 12 is disposed on the inner peripheral side of the first member 11 and on the axis C, and is displaced upward with respect to the first member 11. A bolt hole is formed in the upper end surface of the cylindrical portion of the second member 12. The second member 12 is attached to the engine side via a bolt attached to the bolt hole.

[0019] The vibration isolation base 13 is a member made of an elastic body such as rubber or thermoplastic elastomer formed in a substantially umbrella shape. The vibration isolation base 13 is vulcanized and adhered to the inner peripheral surfaces of the large-diameter portion 11a and the reduced-diameter portion 11b of the first member 11 and the outer peripheral surface of the second member 12 (the outer peripheral surface of the cylindrical portion) over the entire circumference, respectively, to connect them. A film portion 14 covering the inner peripheral surface of the small-diameter portion 11c is continuous with the lower end portion of the vibration isolation base 13.

[0020] The lower surface of the vibration isolation base 13 forms the upper wall surface of the gas chamber 24. Also, the lower surface of the vibration isolation base 13 includes a contact portion 15 extending radially inward from the film portion 14 (the inner peripheral surface of the first member 11), a standing portion 16 extending upward from the inner edge of the contact portion 15, an inclined portion 17 inclined upward as it extends radially inward (toward the axis C side) from the upper end edge of the standing portion 16, and a flat surface portion 18 continuous with the inner peripheral edge (upper end edge) of the inclined portion 17.

[0021] The contact portion 15 is an annular surface perpendicular to the axis C, and the restricting portion 20 contacts (presses against) it. The standing portion 16 is a cylindrical surface centered on the axis C, and when the restricting portion 20 presses against the contact portion 15, the contact portion 15 side bulges inward.

[0022] The inclined portion 17 is a conical surface centered on the axis C. The flat surface portion 18 is a circular surface perpendicular to the axis C and is located below the cylindrical portion of the second member 12. The outer diameter of the flat surface portion 18 is larger than the outer diameter of the cylindrical portion of the second member 12.

[0023] The corner portion 19 between the inclined portion 17 and the standing portion 16 is an annular portion that smoothly connects these edges with a curved surface. When the second member 12 is displaced downward or downward and radially with respect to the first member 11, at least a part of the vibration isolation base 13 (especially the inclined portion 17) is compressed and deformed. The larger this deformation amount is, the easier the vicinity of the corner portion 19 of the vibration isolation base 13 is to buckle.

[0024] The restricting portion 20 is a member for suppressing buckling near the corner portion 19, and is made of metal, synthetic resin, or the like. The restricting portion 20 is disc-shaped perpendicular to the axis C, and its radial outer edge is attached to the membrane portion 14. As an attachment method, for example, first, a first member 11 is prepared which has a membrane portion 14 with an inner diameter larger than the outer diameter of the restricting portion 20, and the restricting portion 20 is inserted from the lower end of the membrane portion 14 (small diameter portion 11c). Next, after the restricting portion 20 is brought into contact with the contact portion 15, the first member 11 is drawn (reduced in diameter) to make the outer edge of the restricting portion 20 bite into the membrane portion 14, and the restricting portion 20 is attached to the membrane portion 14.

[0025] The restricting portion 20, which is in contact with the contact portion 15 and attached to the membrane portion 14, protrudes radially inward from the corner portion 19. As a result, when the second member 12 is displaced at least downward relative to the first member 11, the inclined portion 17 and flat surface portion 18 of the vibration-damping base 13 can come into contact with the restricting portion 20, thereby restricting the deformation of the vibration-damping base 13, and making it less likely for the area near the corner portion 19 of the vibration-damping base 13 to buckle. Therefore, the occurrence of cracks in the corner portion 19 due to repeated buckling can be suppressed, and the durability of the vibration-damping base 13 can be improved.

[0026] Here, the first member 11 is attached to the vehicle body and the engine is attached to the second member 12. When no vibration is input to the vibration isolation device 10 supporting the engine, the downward load applied from the engine to the second member 12 is defined as "1W". When the second member 12 is displaced downward relative to the first member 11 due to the application of this load "1W", it is preferable that the inclined portion 17 and the restricting portion 20 do not come into contact. This allows the spring constant of the vibration isolation base 13 to be maintained until the inclined portion 17 and the restricting portion 20 come into contact when vibration is input to the vibration isolation device 10, thereby improving the vibration isolation performance of the vibration isolation base 13.

[0027] Furthermore, it is preferable that the inclined portion 17 and the restricting portion 20 come into contact when vibration is input to the vibration isolation device 10 and a load "2W", which is twice the load "1W", is applied downward to the second member 12. This improves the vibration isolation performance of the vibration isolation base 13 up to the application of a load "2W", and also improves the durability of the vibration isolation base 13 by restricting the deformation of the vibration isolation base 13 with the restricting portion 20 when a larger load is applied.

[0028] The restricting portion 20 has a through-hole 21 that penetrates through its radial center in the direction of axis C. Since the restricting portion 20 forms the lower wall surface of the gas chamber 24, the gas chamber 24 is open to the atmosphere through the through-hole 21. Therefore, when the volume of the gas chamber 24 changes due to the relative displacement between the first member 11 and the second member 12, gas flows in and out through the through-hole 21. This suppresses the rise in the internal pressure of the gas chamber 24.

[0029] Furthermore, the slower the rate at which gas flows in and out through the through-holes 21, the easier it is for the air spring function of the gas chamber 24 to be exerted when there is relative displacement between the first member 11 and the second member 12. Therefore, by appropriately adjusting the size and number of through-holes 21, the rate at which gas flows in and out can be easily adjusted, and thus the spring characteristics of the gas chamber 24 can be easily adjusted.

[0030] The edge of the through-hole 21 is located radially outward from the inner peripheral edge of the inclined portion 17, specifically below the radial center of the inclined portion 17. This allows for a faster inflow and outflow velocity of gas through the through-hole 21, so that the spring characteristics of the air spring in the gas chamber 24 have almost no effect on the spring characteristics of the vibration-damping base 13.

[0031] Furthermore, since the edge of the through-hole 21 is located radially outward from the inner peripheral edge of the inclined portion 17, deformation of the portion of the vibration-damping base 13 that is far from the corner portion 19 can be more easily tolerated. This improves the vibration-damping performance of the vibration-damping base 13.

[0032] The inner edge of the restricting portion 20 that forms the through-hole 21 curves smoothly downward. This makes it difficult for the deformed vibration-damping base 13 to bite into the inner edge of the restricting portion 20 (the edge of the through-hole 21), thereby improving the durability of the vibration-damping base 13.

[0033] The restricting portion 20 is located in the center of the first member 11 in the direction of axis C, and the small diameter portion 11c extends downward from the restricting portion 20. This allows the vibration isolation device 10 to be manufactured by reusing parts from a liquid-filled vibration isolation device that forms a liquid chamber between a diaphragm that closes the lower end of the small diameter portion 11c and the vibration isolation base 13. Specifically, the first member 11, the second member 12, the vibration isolation base 13, and the membrane portion 14 can be used in common with the vibration isolation device 10 and the liquid-filled vibration isolation device.

[0034] Next, a second embodiment will be described with reference to Figure 2. In the second embodiment, a case in which a protrusion 32 is provided on a part of the regulating portion 31 will be described. Note that parts identical to those in the first embodiment are denoted by the same reference numerals and their descriptions are omitted below. Figure 2 is a cross-sectional view of the vibration isolation device 30 in the second embodiment.

[0035] The regulating portion 31 of the vibration isolation device 30 is provided with a protrusion 32 that projects toward the inclined portion 17. This makes it easier to bring the vibration isolation base 13 into contact with the protrusion 32 of the regulating portion 31 earlier when the second member 12 is displaced downward relative to the first member 11, compared to the first embodiment which does not have a protrusion 32. As a result, the deformation of the vibration isolation base 13 can be restricted earlier, making it less likely for the area near the corner 19 to buckle, and thus the durability of the vibration isolation base 13 can be further improved.

[0036] The protrusion 32 is provided in a continuous annular shape around the entire circumference. This prevents stress from concentrating on a part of the circumferential direction of the vibration-damping base 13 when the vibration-damping base 13 and the protrusion 32 come into contact. Therefore, the durability of the vibration-damping base 13 can be improved.

[0037] The protruding portion 32 comprises a vertical wall portion 33 rising vertically (parallel to axis C) from the flat portion of the regulating portion 31, an inclined wall portion 34 that slopes parallel to the inclined portion 17 from the upper end of the vertical wall portion 33, and a flat wall portion 35 that extends radially inward from the inner edge of the inclined wall portion 34. The shapes of the vertical wall portion 33 and the inclined wall portion 34 are formed along the vertical portion 16, corner portion 19, and inclined portion 17 in an unloaded state where no load is applied from the engine.

[0038] This makes it easier to bring the inclined portion 17 and the inclined wall portion 34 of the vibration-damping base 13 into surface contact when the second member 12 is displaced downward relative to the first member 11. Furthermore, when the second member 12 is displaced radially relative to the first member 11, it makes it easier to bring not only the inclined portion 17 and the inclined wall portion 34 into surface contact, but also the upright portion 16 and the upright wall portion 33 into surface contact. Moreover, when the second member 12 is displaced downward and radially relative to the first member 11, it makes it easier to bring the corner portion 19 into contact with the corner between the inclined wall portion 34 and the upright wall portion 33. As a result, the strain during deformation of the vibration-damping base 13 can be suppressed from concentrating in a part of the vibration-damping base 13, thereby further improving the durability of the vibration-damping base 13.

[0039] Furthermore, the gaps between the vertical wall portion 33 and the inclined wall portion 34 and the upright portion 16, the corner portion 19, and the inclined portion 17 are formed to be substantially constant. This makes it easier to bring the vibration-damping base 13 and the protrusion 32 into surface contact when the second member 12 is displaced at least downward relative to the first member 11. As a result, the concentration of strain on a part of the vibration-damping base 13 during deformation can be further suppressed, thereby further improving the durability of the vibration-damping base 13.

[0040] The flat wall portion 35 is perpendicular to the axis C. A part of the flat wall portion 35 faces a part of the inclined portion 17 in the direction of axis C. As a result, when the second member 12 is displaced downward relative to the first member 11, the second member 12 is displaced further downward from the point where the inclined portion 17 and the inclined wall portion 34 come into contact, causing the flat wall portion 35 and the inclined portion 17 to come into contact. This allows the deformation of the vibration-damping base 13 to be restricted while gradually increasing the spring constant of the vibration-damping base 13. Therefore, shocks and abnormal noises that occur when the spring constant of the vibration-damping base 13 increases rapidly can be suppressed.

[0041] A through-hole 36 is formed in the flat wall portion 35, penetrating through the radial center in the direction of axis C. The inner edge of the flat wall portion 35 that forms the through-hole 36 curves smoothly downward. This makes it difficult for the deformed vibration-damping base 13 to become embedded in the inner edge of the flat wall portion 35 (the edge of the through-hole 21), thereby improving the durability of the vibration-damping base 13.

[0042] The edge of the through-hole 36 is located radially inward from the inner peripheral edge of the inclined portion 17. This slows down the velocity of gas flowing in and out of the through-hole 36, making it easier for the air spring function of the gas chamber 24 to be exerted when there is relative displacement between the first member 11 and the second member 12. As a result, shocks and abnormal noises that occur when the vibration-damping base 13 and the regulating portion 31 come into contact can be easily mitigated by the air spring function of the gas chamber 24.

[0043] Next, a third embodiment will be described with reference to Figure 3. In the third embodiment, an extension 42 is provided to improve the holding force of the restricting portion 41 on the first member 11. Note that parts identical to those in the first embodiment are denoted by the same reference numerals and their descriptions are omitted below. Figure 3 is a cross-sectional view of the vibration isolation device 40 in the third embodiment.

[0044] The regulating portion 41 of the vibration isolation device 40 includes an extension portion 42 that extends downward from the radial outer edge portion that contacts the contact portion 15. The regulating portion 41 is a substantially flat plate-shaped regulating portion 20 in the first embodiment with the extension portion 42 provided.

[0045] Since this extension 42 is attached to the membrane portion 14 (the inner circumferential surface of the first member 11), the holding force of the restricting portion 41 on the first member 11 and the membrane portion 14 can be improved, and the restricting portion 41 can be made less likely to shift in the direction of axis C or in a direction tilted from axis C. Therefore, the displacement of the vibration-damping base 13 can be easily restricted by the restricting portion 41, making the vicinity of the corner portion 19 less likely to buckle, and thus the durability of the vibration-damping base 13 can be further improved.

[0046] Furthermore, the extension portion 42 is provided around the entire circumference of the outer edge of the restricting portion 41 and is formed in a cylindrical shape centered on axis C. The extension portion 42 is attached to the membrane portion 14 (the inner surface of the first member 11) by the outer surface of the extension portion 42 being in close contact with the membrane portion 14 (the inner surface of the first member 11) around its entire circumference and along its entire length in the direction of axis C. As a result, the holding force (resistance to slippage) of the restricting portion 41 relative to the first member 11 can be further improved.

[0047] The first member 11, which holds the extension 42 of the restricting portion 41 via the membrane portion 14, has its lower end bent radially inward. This makes it difficult for the extension 42 to slip downward from the first member 11. Furthermore, since a part of the membrane portion 14 is sandwiched between the bent lower end of the first member 11 and the lower end of the extension 42, the elastic reaction force of this membrane portion 14 makes it easier to press the restricting portion 41 against the contact portion 15. As a result, the displacement of the restricting portion 41 in the axial direction C relative to the first member 11 can be further suppressed.

[0048] The corner between the outer edge of the restricting portion 41 and the extension portion 42 is smoothly curved. As a result, even if the corner between the outer edge of the restricting portion 41 and the extension portion 42 comes into close contact with the film portion 14 due to the drawing process of the first member 11, the corner is less likely to dig into the film portion 14. Consequently, the durability of the film portion 14 can be improved.

[0049] Next, a fourth embodiment will be described with reference to Figure 4. In the fourth embodiment, a recess 52 is provided on the radially inner side of the regulating portion 51. Note that parts identical to those in the first embodiment are denoted by the same reference numerals and their descriptions are omitted below. Figure 4 is a cross-sectional view of the vibration isolation device 50 in the fourth embodiment.

[0050] The restricting portion 51 of the vibration isolation device 50 includes a recess 52 that is recessed downward at a position radially inward from the corner portion 19. The restricting portion 51, which is radially outward from the recess 52, can restrict deformation of the vibration isolation base 13 near the corner portion 19, while the recess 52 allows deformation of the vibration isolation base 13 at a distance from the corner portion 19. This makes it difficult for the area near the corner portion 19 to buckle, while improving the vibration isolation performance of the vibration isolation base 13.

[0051] In particular, the outer edge of the recess 52 is located radially outward from the inner edge of the inclined portion 17. This allows for a wider range of deformation of the vibration-damping base 13 due to the recess 52, thereby improving the vibration-damping performance of the vibration-damping base 13.

[0052] Since the outer edge of the recess 52 is smoothly curved downwards, it is difficult for the deformed vibration-damping base 13 to become embedded in the outer edge of the recess 52. Therefore, the durability of the vibration-damping base 13 can be improved.

[0053] A through-hole 53 is formed in the recess 52, penetrating through the radial center in the direction of axis C. The inner diameter of the through-hole 53 is smaller than the outer diameter of the cylindrical portion of the second member 12. As a result, even if the second member 12 is displaced downward relative to the first member 11, it is difficult for the second member 12 to be inserted into the through-hole 53. Therefore, even if the inner edge of the restricting portion 51 that forms the through-hole 53 is not smoothly curved downward but faces radially inward, it is difficult for the vibration-damping base 13 to bite into its inner edge (the edge of the through-hole 53). As a result, the durability of the vibration-damping base 13 can be improved.

[0054] Furthermore, since the inner diameter of the through-hole 53 is smaller than the outer diameter of the cylindrical portion of the second member 12, the speed of gas inflow and outflow through the through-hole 53 can be slowed down, making it easier for the air spring function of the gas chamber 24 to be exerted when there is relative displacement between the first member 11 and the second member 12. As a result, shocks and abnormal noises that occur when the vibration-damping base 13 and the regulating part 51 come into contact can be more easily mitigated by the air spring function of the gas chamber 24.

[0055] Although the present invention has been described above based on embodiments, it can be easily inferred that the present invention is not limited in any way to the above embodiments, and that various improvements and modifications are possible without departing from the spirit of the present invention. For example, the cylindrical portion of the second member 12 may be configured to taper towards the bottom. Alternatively, the second member 12 may be positioned at a location offset radially from the axis C.

[0056] In the above configuration, engine mounts were given as examples of applications for the vibration damping devices 10, 30, 40, and 50, but the applications are arbitrary. Other examples of applications include motor mounts, member mounts, and differential mounts. Furthermore, it is not limited to attaching the first member 11 to the vibration receiving side such as the vehicle body and attaching the second member 12 to the vibration source side such as the engine; the second member 12 may be attached to the vibration receiving side and the first member 11 to the vibration source side.

[0057] Parts of each of the above embodiments may be replaced with parts of other embodiments, and parts of each of the above embodiments may be added to other embodiments. For example, the extension 42 of the third embodiment may be provided on the restricting parts 31 and 51 of the second and fourth embodiments. Also, the inner edges of the restricting parts 20, 31 and 41 of the first to third embodiments do not need to be curved downwards, as is the case with the inner edge of the restricting part 51 (edge ​​of the through hole 53) of the fourth embodiment.

[0058] Some parts of the above configuration may be omitted. For example, the membrane portion 14 may be omitted and the regulating portions 20, 31, 41, and 51 may be attached to the inner circumferential surface of the first member 11. Also, the small diameter portion 11c below the regulating portions 20, 31, and 51 may be omitted.

[0059] In the above configuration, a case was described in which one through-hole 21, 36, or 53 is provided in the radial center of the regulating sections 20, 31, 41, or 51. However, the position, number, and size of the through-holes may be changed as appropriate. Alternatively, the gas chamber 24 may be sealed with gas (for example, air or nitrogen gas) without providing the through-holes 21, 36, or 53. Furthermore, the gas chamber 24 may be sealed by closing the lower end of the extension section 42.

[0060] In the second embodiment described above, the case in which the shape of the protrusion 32 (vertical wall portion 33 and inclined wall portion 34) is formed along the vertical portion 16, corner portion 19, and inclined portion 17 in an unloaded state was explained, but the shape, dimensions, and arrangement of the protrusion may be changed as appropriate. For example, the inclined wall portion 34 may be omitted and a flat wall portion 35 may be connected to the upper end of the vertical wall portion 33, or the vertical wall portion 33 may be omitted and the protrusion may be formed from the inclined wall portion 34 and the flat wall portion 35.

[0061] Furthermore, multiple protrusions may be arranged spaced apart in the circumferential direction. In this case, when the deformed vibration-damping base 13 comes into contact with a protrusion, it becomes more difficult to seal the gas chamber 24 radially outside the contact point. This suppresses large fluctuations in the internal pressure of the sealed gas chamber 24 due to further deformation of the vibration-damping base 13, and suppresses abnormal noises caused by the inflow and outflow of gas accompanying the release of internal pressure. [Explanation of Symbols]

[0062] 10, 30, 40, 50 Vibration Isolator 11. First Member 12 Second Member 13 Vibration Isolation Base 14 Membrane part 15 Contact area 16. Erecting section 17 Slope 19 Corner 20, 31, 41, 51 Regulatory Department 21, 36, 53 Through holes 24 Gas chamber 32 Convex part 42 Extension 52 recess C axis

Claims

1. A cylindrical first member surrounding the axis, A second member is positioned on the inner circumference side of the first member, An elastic vibration-damping base connecting the inner circumferential surface of the first member and the second member, A restricting portion is attached to the inner circumferential surface of the first member or to the membrane portion of the vibration-damping base covering the inner circumferential surface of the first member, and restricts the deformation of the vibration-damping base, The device comprises a gas chamber in which gas is contained, the first wall surface in the axial direction is formed by the vibration-damping base, and the second wall surface opposite to the first side in the axial direction is formed by the restricting portion, The second side surface of the vibration-damping base has a contact portion that extends radially inward from the inner circumferential surface of the first member and contacts the restricting portion, An upright portion extending from the inner edge of the contact portion to the first side, It comprises an inclined portion that slopes toward the first side as it extends radially inward from the upright portion, The restricting portion protrudes radially inward from the corner between the inclined portion and the upright portion. The regulating portion has a through hole that penetrates in the axial direction. The gas chamber is opened to the atmosphere through the through-hole. The inclined portion is conical in shape with an inner periphery, The edge of the through-hole is located radially outward from the inner edge of the inclined portion, such that the inner diameter of the through-hole is greater than the diameter of the inner edge of the inclined portion. A vibration isolation device characterized in that the inner edge of the restricting portion that forms the through hole is smoothly curved toward the second side.

2. The vibration isolation device according to claim 1, characterized in that the restricting portion includes a protrusion that projects toward the inclined portion.

3. The vibration isolation device according to claim 2, characterized in that the protrusions are shaped to conform to the upright portion, the corner portion, and the inclined portion in an unloaded state.

4. The restricting portion includes an extension portion extending from the radial outer edge portion toward the second side, The vibration isolation device according to any one of claims 1 to 3, characterized in that the extension is attached to the inner circumferential surface of the first member or the membrane portion.

5. The vibration isolation device according to any one of claims 1 to 4, characterized in that the restricting portion has a recess formed by recessing toward the second side at a position located radially inward from the corner portion.

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