Fluid-enclosed vibration isolator

Abstract

This invention provides a novel fluid-sealed vibration damping device that enables control of its properties by applying a magnetic field to a magnetic functional fluid, and can suppress the enlargement of external assembly components such as mounting brackets and vibration damping connection components. A fluid-sealed vibration damping device (10) has multiple fluid chambers (46) filled with a magnetic functional fluid interconnected by a throttling passage (48). A magnetic unit (14) that applies a magnetic field to the throttling passage is disposed in an outer sleeve state on an outer cylinder member (18). The magnetic unit has a magnetic field generating part (50) that generates a magnetic field and a magnetic circuit forming part (52) that induces magnetic flux. The magnetic field is applied to the throttling passage from a magnetic gap part (68) of the magnetic circuit forming part disposed on the outer periphery of the throttling passage. A mounting part (70) is provided on the outer peripheral surface of the outer cylinder member, axially offset from the magnetic field generating part. The mounting part is fitted with an external assembly component (72) that connects the outer cylinder member to the vibration damping connection component (84).

Description

Technical Field

[0001] This invention relates to vibration damping devices for use in motor vehicle engine mounts and the like, and in particular, to fluid-sealed vibration damping devices that utilize the vibration damping effect generated by the flow of fluid sealed inside. Background Technology

[0002] Fluid-sealed vibration damping devices, such as those used in engine mounts and differential mounts of motor vehicles, have long been known. As disclosed in German Patent Application Publication No. 102011117749 (Patent Document 1), such devices have the following structure: an inner component and an outer cylinder component are elastically connected by a main body rubber elastomer; multiple fluid chambers are provided inside, and throttling channels are formed to connect these fluid chambers. Furthermore, the sealed fluid flows between the fluid chambers through the throttling channels, thereby enabling the fluid-sealed vibration damping device to exert a vibration damping effect based on the flow of the fluid.

[0003] Furthermore, Patent Document 1 proposes using a magnetically viscous fluid with varying viscosity as the sealing fluid for the fluid chamber, depending on the strength of the applied magnetic field. The fluid-sealed vibration damping device of Patent Document 1 includes a magnetic unit that generates a magnetic field by energizing it. By applying the magnetic field generated by the magnetic unit to the magnetically viscous fluid, the flow characteristics of the magnetically viscous fluid can be changed. Moreover, according to the fluid-sealed vibration damping device of Patent Document 1, by controlling the strength of the magnetic field applied from the magnetic unit to the magnetically viscous fluid, the fluidity (viscosity) of the magnetically viscous fluid can be controlled, thereby changing characteristics such as damping and support rigidity, thus achieving excellent vibration damping performance and differential gear support performance.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: German Patent Application Publication No. 102011117749 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] However, as in Patent Document 1 Figure 4 As shown, when the magnetic unit is installed inside a fluid-sealed vibration damping device, a liquid-tight sealing structure is required to prevent the energized magnetic unit from contacting the sealed fluid, thus complicating the construction. Therefore, as in Patent Document 1... Figure 2 , 3 As shown, the magnetic unit can also be configured to be mounted on the outer periphery of the outer cylinder component.

[0009] However, when the magnetic unit is installed on the outer peripheral surface of the outer cylinder component, the outer assembly component that connects the vibration-damping connection object component to the outer cylinder component is located on the outer periphery of the magnetic unit in the mounting part for the outer cylinder component. This presents a problem, namely, the large size of the mounting part for the outer cylinder component can easily become a problem.

[0010] The present invention addresses the problem of providing a novel fluid-sealed vibration damping device that enables control of its characteristics by applying a magnetic field to a magnetic functional fluid, while simultaneously suppressing the enlargement of external assembly components that connect the outer cylinder component to the vibration damping connection component.

[0011] means for solving problems

[0012] The following description focuses on preferred embodiments for mastering the present invention. However, these embodiments are illustrative and can be appropriately combined and used together. Furthermore, the multiple constituent elements shown in each embodiment can be independently identified and used as much as possible, and can also be appropriately combined and used in combination with any constituent element described in other embodiments. Therefore, the present invention is not limited to the embodiments described below, and various other embodiments can be implemented.

[0013] The first method is a fluid-sealed vibration damping device. The inner component and outer cylinder component of the fluid-sealed vibration damping device are connected by a main body rubber elastomer. Multiple fluid chambers containing magnetic functional fluid are disposed inside the sealed vibration damping device. The sealed vibration damping device is provided with a throttling passage that connects these multiple fluid chambers to each other. A magnetic unit that applies a magnetic field to the magnetic functional fluid in the throttling passage is disposed in an outer sleeve state on the outer cylinder component. The magnetic unit includes: a magnetic field generating part that generates a magnetic field by energizing; and a magnetic circuit forming part that induces the magnetic flux of the magnetic field generated by the magnetic field generating part. A magnetic gap part disposed in the magnetic circuit forming part is arranged on the outer periphery of the throttling passage. The magnetic field is applied from the magnetic gap part to the magnetic functional fluid in the throttling passage. A mounting part is provided on the outer peripheral surface of the outer cylinder component at a position axially offset from the magnetic field generating part. The mounting part is equipped with an outer assembly component that connects the outer cylinder component to the vibration damping connection component.

[0014] According to the fluid-sealed vibration damping device constructed in this manner, a magnetic field generated by a magnetic unit installed on the outer peripheral surface of the outer cylinder member is applied to a magnetic functional fluid sealed in the fluid chamber. This allows for modification of characteristics such as vibration damping performance, vibration isolation performance, and the support rigidity of the power unit, differential gears, etc. In particular, by controlling the intensity of the magnetic field applied to the magnetic functional fluid, the characteristics of the fluid-sealed vibration damping device described above can be adjusted and set, thereby achieving excellent performance. Furthermore, since the magnetic unit is installed on the outer peripheral surface of the outer cylinder member, the magnetic unit does not come into contact with the magnetic functional fluid sealed in the fluid chamber, simplifying the installation structure.

[0015] The mounting portion of the outer cylinder component, which is equipped with external assembly components such as mounting brackets and vibration damping connection components, is designed to be axially offset from the magnetic field generating portion, such as the coil constituting the magnetic force unit. Therefore, compared to the case where the external assembly components are located on the outer periphery of the magnetic field generating portion, the diameter of the mounting portion of the external assembly components on the outer cylinder component can be reduced.

[0016] The second method is based on the fluid-sealed vibration damping device described in the first method, wherein the outer assembly component is formed as a mounting bracket connecting the outer cylinder component and the vibration damping connection object component, and the mounting bracket installed on the outer cylinder component passes through the magnetic circuit forming portion.

[0017] According to the fluid-sealed vibration damping device constructed in accordance with this method, the mounting bracket can be installed on the outer circumferential surface of the outer cylinder component at a position offset from the magnetic field generating part along the axial direction, and the degree of freedom in the arrangement of the magnetic circuit forming part is expanded.

[0018] The third method is based on the fluid-sealed vibration damping device described in the second method, wherein the magnetic circuit forming part includes: an inner peripheral magnetic circuit that extends axially along the inner peripheral side of the magnetic field generating part; and an outer peripheral magnetic circuit that extends axially along the outer peripheral side of the magnetic field generating part. The magnetic gap portion of the magnetic circuit forming part is formed in the inner peripheral magnetic circuit of the magnetic circuit forming part, and the mounting bracket protrudes outward through the outer peripheral magnetic circuit of the magnetic circuit forming part.

[0019] According to the fluid-sealed vibration damping device constructed in accordance with this method, a magnetic gap is formed in the inner circumferential magnetic circuit, thereby enabling the magnetic field to be efficiently applied from the magnetic gap to the magnetic functional fluid sealed in the inner circumferential side of the outer cylinder member. Furthermore, the mounting bracket extends through the outer circumferential magnetic circuit, thereby allowing, for example, the fastening portion of the mounting bracket to the vibration damping connection member to protrude further outward than the magnetic circuit forming portion.

[0020] The fourth method is based on the fluid-sealed vibration damping device described in any of the first to third methods, wherein a plurality of the magnetic field generating units are arranged on both sides of the axial direction relative to the mounting portion of the outer cylinder member.

[0021] According to the fluid-sealed vibration damping device constructed in accordance with this method, the mounting position of the outer assembly member towards the outer cylinder member is axially spaced between multiple magnetic field generating units. For example, it is easy to mount the outer assembly member onto the outer cylinder member at a position close to the axial center. Furthermore, by providing magnetic field generating units on both sides of the mounting position of the outer assembly member towards the outer cylinder member, the magnetic field generating units can be arranged with excellent space efficiency, thereby making it possible to expand the degree of freedom in setting the intensity of the magnetic field generated by the magnetic field generating units.

[0022] The fifth method is based on the fluid-sealed vibration damping device described in any of the first to fourth methods, wherein the magnetic circuit forming part is formed by two groove-shaped metal parts arranged facing each other in a concave shape that opens toward the axial inner side, the magnetic field generating part is arranged inside each of the groove-shaped metal parts, and the magnetic gap part is provided between the inner peripheral walls of the two groove-shaped metal parts.

[0023] According to the fluid-sealed vibration damping device constructed in accordance with this method, it is easy to obtain a magnetic unit in which a magnetic circuit forming part is provided around the magnetic field generating part. In addition, by separating the inner peripheral sidewalls of two opposing groove-shaped metal parts along the axial direction, it is easy to provide a magnetic gap between the inner peripheral walls of the two groove-shaped metal parts.

[0024] Invention Effects

[0025] According to the present invention, in the fluid-sealed vibration damping device, the characteristics can be controlled by applying a magnetic field to the magnetic functional fluid, and the enlargement of the mounting portion of the outer cylinder member in the outer assembly member that realizes the connection between the outer cylinder member and the vibration damping connection member can be suppressed. Attached Figure Description

[0026] Figure 1 This is a perspective view showing the engine bracket as a first embodiment of the present invention.

[0027] Figure 2 yes Figure 1 The cross-sectional view of the engine mount shown is equivalent to Figure 3 The diagram of section II-II.

[0028] Figure 3 yes Figure 2 Sectional view III-III.

[0029] Figure 4 To constitute Figure 1 A three-dimensional view showing the state in which a throttling component is installed on an integral vulcanized molded part of the main body rubber elastomer of the engine mount.

[0030] Figure 5 It constitutes Figure 1 Front view of the throttling component of the engine mount.

[0031] Figure 6 This is a cross-sectional view showing the engine bracket as a second embodiment of the present invention.

[0032] Explanation of reference numerals in the attached figures

[0033] 10: Engine mount (first embodiment fluid-sealed vibration damping device);

[0034] 12: Main body of the support frame;

[0035] 14: Magnetic unit;

[0036] 16: Internal components;

[0037] 18: Outer cylinder components;

[0038] 20: Main body rubber elastomer;

[0039] 22: Limiting component;

[0040] 24: Intermediate sleeve;

[0041] 26: Window area;

[0042] 28: Groove-shaped part;

[0043] 30: Pocket area;

[0044] 32: Interlocking rubber;

[0045] 34: Throttling components;

[0046] 36: Narrow section;

[0047] 38: Groove;

[0048] 40: Opening;

[0049] 42: Separating rubber;

[0050] 44: Sealing rubber layer;

[0051] 46: Fluid chamber;

[0052] 48: Streamline traffic flow;

[0053] 50: Coil (magnetic field generating part);

[0054] 52: Yoke (magnetic circuit forming part);

[0055] 54: Channel-shaped metal parts;

[0056] 56: Bollard;

[0057] 58: Inner peripheral wall portion;

[0058] 60: Peripheral wall portion;

[0059] 62: Bottom wall;

[0060] 64: Inner peripheral magnetic circuit;

[0061] 66: Peripheral magnetic circuit;

[0062] 68: Magnetic gap section;

[0063] 70: Installation Department;

[0064] 72: Install bracket (external assembly component);

[0065] 74: Install the cylinder part;

[0066] 76: chimeric protrusion;

[0067] 78: Fastening plate;

[0068] 80: Bolt hole;

[0069] 82: Insert through window;

[0070] 84: Vehicle body (vibration damping connection components);

[0071] 90: Suspension bushing (second embodiment fluid-sealed vibration damping device);

[0072] 92: Bushing body;

[0073] 94: Magnetic unit;

[0074] 96: Yoke (magnetic circuit forming part);

[0075] 98: Linkage arm (vibration-damping connection component, external assembly component);

[0076] 100: Cylindrical assembly section. Detailed Implementation

[0077] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0078] Figures 1-3 An engine mount 10 for a motor vehicle is shown as a first embodiment of a fluid-sealed vibration damping device configured according to the present invention. The engine mount 10 has a configuration in which a magnetic unit 14 is mounted on a mount body 12. The mount body 12 has a configuration in which an inner member 16 and an outer cylinder member 18 are connected by a main body rubber elastomer 20. In the following description, in principle, the up-down direction refers to... Figure 2 The up and down directions and the left and right directions refer to... Figure 2The left-right and front-back directions are used as the axis. Figure 1 The left and right directions in the middle.

[0079] The inner member 16 is formed into a generally cylindrical shape extending in a straight line, and is a high-rigidity member made of metal, synthetic resin, or the like. The inner member 16 is preferably made of a non-magnetic material such as stainless steel or synthetic resin. A limiting member 22 is installed at the axial central portion of the inner member 16. The limiting member 22 is disposed in an outer sleeve state on the inner member 16 and protrudes towards both sides in the radial (vertical) direction.

[0080] An intermediate sleeve 24 is disposed on the outer periphery of the inner member 16. The intermediate sleeve 24 is formed into a generally cylindrical shape with a larger diameter than the inner member 16, and is disposed to fit over the inner member 16. The intermediate sleeve 24 is preferably made of a non-magnetic material such as stainless steel or synthetic resin. The intermediate sleeve 24 is located in one radial direction ( Figure 2 The intermediate sleeve 24 has a pair of windows 26, 26 on both sides (vertically and vertically). The window 26 extends circumferentially with a length of less than half a circumference and passes through the intermediate sleeve 24 in the vertical direction. Grooves 28, 28 are formed between the windows 26, 26 in the intermediate sleeve 24. The groove 28 is located at the axial center of the intermediate sleeve 24 and is configured to extend circumferentially on a concave cross-section that opens to the outer circumferential surface.

[0081] The inner component 16 and the intermediate sleeve 24 are elastically connected by the main rubber elastomer 20. The main rubber elastomer 20 is formed into a generally cylindrical shape with a thick wall, with its inner circumferential surface fixedly mounted to the inner component 16 and its outer circumferential surface fixedly mounted to the outer cylinder component 18. In this embodiment, the main rubber elastomer 20 is formed as an integral vulcanized molded part having the inner component 16 and the intermediate sleeve 24, with the inner component 16 and the intermediate sleeve 24 vulcanized and bonded to the main rubber elastomer 20. Furthermore, after the main rubber elastomer 20 is formed, the intermediate sleeve 24 is radially reduced by an eight-piece diameter reduction process, thereby reducing tensile deformation caused by cooling shrinkage of the main rubber elastomer 20 after forming.

[0082] The main rubber elastomer 20 has a radial direction ( Figure 2 A pair of pocket portions 30, 30 with openings on both sides (vertically and vertically) are provided. Each pocket portion 30 has an opening shape corresponding to the window portion 26, and its periphery is fixedly mounted to the intermediate sleeve 24. Within the integrally vulcanized part of the main rubber elastomer 20, the pocket portion 30 opens outwards through the window portion 26. A limiting member 22, mounted on the inner member 16, protrudes radially from the inner peripheral side towards the outer peripheral side into each pocket portion 30.

[0083] The inner surfaces of the grooved portions 28 of the intermediate sleeve 24 are respectively covered by interlocking rubber 32 integrally formed with the main rubber elastomer 20. Furthermore, as... Figure 4As shown, throttling members 34 are installed on the grooved portions 28, 28. The throttling member 34 is formed into a roughly semi-cylindrical shape extending circumferentially for nearly half its length, and is configured to span the window portion 26 circumferentially, with both circumferential ends inserted into the grooved portions 28, 28. One circumferential end of the throttling member 34 is formed into a narrow portion 36 with a smaller axial dimension than the other portions. Also as... Figure 5 As shown, a groove 38 is formed in the narrow portion 36 of the throttling member 34, opening outwards from the central portion in the axial direction and extending circumferentially. Additionally, in other portions of the throttling member 34 that are circumferentially offset from the narrow portion 36, an opening 40 with an axial dimension larger than the groove 38 and extending radially is provided. The circumferential end of the opening 40 on the groove 38 side gradually narrows axially towards the groove 38, and the groove 38 and the opening 40 are continuous in the circumferential direction. The throttling member 34 is formed of a strongly magnetic material such as iron, nickel, chromium, or soft ferrite.

[0084] Two throttling members 34, 34 are arranged radially toward each other and are installed in the intermediate sleeve 24 with their narrow portions 36, 36 inserted into the groove 28 of one side from both circumferential sides. The circumferential ends opposite to the narrow portions 36, 36 of the two throttling members 34, 34 are inserted into the groove 28 of the other side from both circumferential sides. A separating rubber 42 protruding outward from the fitting rubber 32 is arranged between these circumferential ends opposite to the narrow portions 36, 36. The two circumferential ends of each throttling member 34 are inserted into the grooves 28, 28, thereby arranging each throttling member 34 to circumferentially span the window 26 of one side, and the opening 40 communicates with the pocket 30 through the window 26.

[0085] An outer cylinder member 18 is mounted on an integrally vulcanized molded part of the main rubber elastomer 20. The outer cylinder member 18 is formed into a generally cylindrical shape with a larger diameter than the intermediate sleeve 24, and is preferably made of a non-magnetic material such as stainless steel or synthetic resin. The inner circumferential surface of the outer cylinder member 18 is covered by a sealing rubber layer 44. The outer cylinder member 18 is machined to be fitted over the intermediate sleeve 24, which is fitted with throttling members 34, 34, and thus the inner circumferential surface covered by the sealing rubber layer 44 is pressed against the outer circumferential surface of the intermediate sleeve 24, thereby being fixed to the intermediate sleeve 24. The sealing rubber layer 44 is configured in a compressed state between the overlapping surfaces of the outer cylinder member 18 and the intermediate sleeve 24, and is therefore liquid-tightly sealed. Furthermore, the overlapping surfaces of the outer cylinder member 18 and the throttling members 34, 34 are also liquid-tightly sealed by the sealing rubber layer 44.

[0086] The windows 26 are covered by the outer cylinder member 18, and the outer peripheral openings of the pockets 30 are liquid-sealed by the outer cylinder member 18, thereby forming two fluid chambers 46 inside the engine mount 10. Each fluid chamber 46 is sealed with a magnetic functional fluid. The magnetic functional fluid is a fluid whose viscosity increases under the influence of a magnetic field. The magnetic functional fluid can be any of a magnetic viscous fluid (MRF), a magnetic fluid (MF), or a magnetic composite fluid (MCF) obtained by mixing a magnetic fluid and a magnetic viscous fluid. Preferably, the magnetic functional fluid is a magnetic viscous fluid whose viscosity changes significantly with the influence of a magnetic field; it is also preferable to use a magnetic composite fluid whose viscosity increase can be easily adjusted according to the mixing ratio of the magnetic viscous fluid and the magnetic fluid.

[0087] Magnetic functional fluids are, for example, suspensions or colloidal solutions obtained by dispersing strongly magnetic microparticles in base liquids such as water or oil. Preferably, the surface of the strongly magnetic microparticles is covered by a surfactant, or the strongly magnetic microparticles are dispersed in a base liquid containing a surfactant, so that the strongly magnetic microparticles are difficult to coagulate or precipitate in the base liquid.

[0088] Strongly magnetic microparticles are, for example, metallic particles such as iron, ferrite, and magnetite (magnet), preferably with a particle size of about 8 nm to 10 μm. The base fluid is not particularly limited as long as it can disperse the strongly magnetic microparticles; for example, water, isoparaffins, alkylnaphthalenes, perfluoropolyethers, polyolefins, and silicone oils can be used. Furthermore, the base fluid is preferably an incompressible fluid. Depending on the base fluid, a surfactant is appropriately selected; for example, oleic acid is preferred. In addition, the main difference between magnetic viscous fluids and magnetic fluids is the particle size of the strongly magnetic microparticles; the particle size of the strongly magnetic microparticles in magnetic viscous fluids is larger than that in magnetic fluids.

[0089] Fluid chambers 46 and 46 are interconnected via a throttling passage 48. The outer peripheral openings of the grooves 38 and 38 of the throttling members 34 and 34 are covered and sealed by the outer cylinder member 18, thereby forming the throttling passage 48. The throttling passage 48 extends circumferentially between the fluid chambers 46 and 46, and its two circumferential ends are connected to the fluid chambers 46 and 46. The throttling passage 48 takes into account the wall spring stiffness of the fluid chambers 46 and 46, the viscosity of the magnetic functional fluid, etc., and sets the ratio of the passage cross-sectional area to the passage length. Therefore, according to the vibration frequency of the vibration-damping object, the tuning frequency, which is the resonant frequency of the flowing fluid, is appropriately set.

[0090] Furthermore, in this embodiment, the throttling passage 48 is provided circumferentially between the fluid chambers 46, 46. For example, the throttling passage can be configured to extend circumferentially from the opening of the pocket portion 30, thereby ensuring a longer passage length. Such a long throttling passage is achieved, for example, by forming the groove 38 in the throttling member 34 to be longer in the circumferential direction, thereby shortening the circumferential length of the opening portion 40.

[0091] A magnetic unit 14 is mounted on the support body 12. The magnetic unit 14 includes a coil 50 as a magnetic field generating part and a yoke 52 as a magnetic circuit forming part. More specifically, the magnetic unit 14 of this embodiment has the following structure: two coils 50 are disposed inside two slotted metal parts 54, 54, and the two slotted metal parts 54, 54 are arranged facing each other and open toward the axial inward side.

[0092] The coil 50 is formed of conductive metal wire and is wound on a non-magnetic spool 56. The coil 50 is connected to an external power supply via a connector (not shown) provided on the spool 56, and a magnetic field is generated around the coil 50 by energizing the coil 50.

[0093] The channel-shaped metal part 54 is formed as a continuous ring along the circumference through a concave channel-shaped cross-section with an opening along the axial inner side, and the inner circumferential wall portions 58 and outer circumferential wall portions 60 of each cylindrical part are connected at their outer axial ends by a bottom wall portion 62. The channel-shaped metal part 54 is formed of a strongly magnetic material such as iron, nickel, chromium, or soft ferrite. The coils 50 disposed radially between the inner circumferential wall portions 58 and the outer circumferential wall portions 60 in the channel-shaped metal part 54 overlap the bottom wall portion 62 of the channel-shaped metal part 54 from the axial inner side.

[0094] Two slotted metal pieces 54, 54, each with a coil 50 disposed on its inner side, are arranged facing each other axially, with their outer peripheral walls 60, 60 axially joined together, and their inner peripheral walls 58, 58 axially separated from each other. In this way, the two slotted metal pieces 54, 54 are arranged facing each other, thereby forming a yoke 52. In this embodiment, the inner peripheral magnetic circuit 64 of the yoke 52 is formed by the inner peripheral walls 58, 58 of the slotted metal pieces 54, and the outer peripheral magnetic circuit 66 of the yoke 52 is formed by the outer peripheral walls 60, 60 of the slotted metal pieces 54. The coil 50 is disposed inside the slotted metal piece 54, the inner peripheral magnetic circuit 64 is configured to extend the inner peripheral side of the coil 50 axially, and the outer peripheral magnetic circuit 66 is configured to extend the outer peripheral side of the coil 50 axially. In the inner peripheral magnetic circuit 64 of the yoke 52, a magnetic gap 68 is formed between the inner peripheral walls 58, 58 axially. Furthermore, the magnetic flux of the magnetic field formed around the coil 50 by energizing the coil 50 is induced by the yoke 52, thereby efficiently applying a magnetic field to the outside through the magnetic gap 68. In this embodiment, the outer peripheral wall portions 60, 60 abut against each other in the axial direction, but for example, they may be separated from each other by a distance shorter than the magnetic gap 68.

[0095] The magnetic unit 14 is mounted on the outer peripheral surface of the outer cylinder member 18. That is, the inner peripheral magnetic circuit 64 of the yoke 52 is embedded in the outer peripheral surface of the outer cylinder member 18, thereby fixing the magnetic unit 14 to the outer cylinder member 18 in an outer sleeve state. With the magnetic unit 14 fixed to the outer cylinder member 18, the coils 50, 50 are arranged on the outer periphery of both axial ends of the outer cylinder member 18. In this embodiment, the coils 50, 50 are arranged to protrude further outward along the axial direction than the outer cylinder member 18. In addition, the magnetic gap portion 68 of the yoke 52 is located at the axial central portion of the outer cylinder member 18 and is arranged on the outer periphery of the throttling passage 48. In short, the magnetic gap portion 68 and the throttling passage 48 are aligned with each other in the axial direction. Moreover, the magnetic gap portion 68 is arranged near the throttling passage 48, thereby the magnetic field generated by the coils 50, 50 is guided by the yoke 52 and applied from the magnetic gap portion 68 to the magnetic functional fluid in the throttling passage 48. Furthermore, the magnetic gap 68 is positioned axially inward, away from the coils 50, 50. The outer peripheral surface of the outer cylinder member 18 overlaps with the inner peripheral magnetic circuit 64, and this exposed portion is formed as a mounting portion 70. The mounting portion 70 is positioned axially offset from the coils 50, 50, and is disposed between the coils 50, 50 along their axial direction. In other words, the coils 50, 50 are mounted on the outer peripheral surface of the outer cylinder member 18 on both sides axially offset from the mounting portion 70.

[0096] At a position axially offset from the coils 50, 50 of the magnetic unit 14, a mounting bracket 72, serving as an external assembly component, is installed on the outer peripheral surface of the outer cylinder component 18. For example... Figure 3As shown, the mounting bracket 72 is formed in a generally cylindrical shape and has a mounting cylinder portion 74 that is externally fitted and fixed to the outer peripheral surface of the outer cylinder member 18. The inner peripheral surface of the axial central portion of the mounting cylinder portion 74 has a smaller diameter than the inner peripheral surfaces of the two axial ends, and a fitting protrusion 76 protruding inward is provided at the axial central portion. The mounting cylinder portion 74 is positioned axially between the coils 50 and 50, offset axially from the coils 50 and 50, and the fitting protrusion 76 is fitted and fixed to the mounting portion 70 on the outer peripheral surface of the outer cylinder member 18.

[0097] In this way, the mounting bracket 72 is mounted on the outer peripheral surface of the outer cylinder member 18 at a position where the mounting cylinder 74 is axially offset from the coils 50, 50 of the magnetic unit 14. Therefore, compared with the structure that is arranged on the outer peripheral side of the coils 50, 50, the mounting cylinder 74 is made smaller, thereby avoiding the need for the mounting bracket 72 to be large.

[0098] like Figure 2 As shown, gaps are formed radially between the mounting cylinder portion 74 and the outer cylinder member 18 on both axial sides of the fitting protrusion 76, and the inner peripheral wall portions 58, 58 of the magnetic unit 14 are inserted into these gaps. In other words, the fitting protrusion 76 of the mounting cylinder portion 74 passes through the magnetic gap portion 68 of the yoke 52 and fits into the mounting portion 70 on the outer peripheral surface of the outer cylinder member 18, thereby mounting the mounting bracket 72 onto the outer cylinder member 18. Although the mounting bracket 72 is made of non-magnetic materials such as stainless steel or synthetic resin and is positioned close to the magnetic gap portion 68, magnetic flux is difficult to escape from the yoke 52 to the mounting bracket 72.

[0099] like Figure 3 As shown, the mounting bracket 72 has two fastening plates 78, 78 protruding outwards from the mounting cylinder 74. The fastening plate 78 is formed in a generally rectangular plate shape and has a bolt hole 80 extending through its thickness. The two fastening plates 78, 78 protrude from the mounting cylinder 74 to both sides in the left-right direction. The two fastening plates 78, 78 are offset from the center of the mounting cylinder 74 in the vertical direction and are positioned at positions offset from each other in the vertical direction. Figure 1 , Figure 3 As shown, the fastening plates 78 and 78 protrude further outward than the magnetic unit 14 through the insertion windows 82 and 82 of the outer peripheral magnetic circuit 66 that passes through the yoke 52.

[0100] In this way, the fastening plates 78, 78 of the mounting bracket 72 are formed to protrude outwards through the outer peripheral magnetic circuit 66 of the yoke 52. This prevents the mounting bracket 72 from restricting the structure of the yoke 52 due to its mounting structure (mounting position) towards the vehicle, or the mounting bracket 72 from restricting its mounting structure (mounting position) towards the vehicle due to the structure of the yoke 52. This allows for a high degree of design freedom.

[0101] The engine mount 10, configured in this way, is mounted to the power unit side of the vibration-damping connection member, for example, via an inner bolt (not shown) through which an inner member 16 is inserted. Additionally, two fastening plates 78, 78 bolts are fixed to the vehicle body 84 side, which is the other vibration-damping connection member, via the outer cylindrical member 18, which is mounted to the vehicle body 84 side via a mounting bracket 72. Thus, the power unit (not shown) is vibration-damped and supported on the vehicle body 84 by the engine mount 10.

[0102] In a vehicle assembly configuration as described above, when vibration is input between the inner member 16 and the outer cylinder member 18 of the engine mount 10, resulting in relative pressure variations between the fluid chambers 46, 46, fluid flow occurs between these fluid chambers 46, 46 through the throttling passage 48. In particular, when the frequency of the input vibration is equivalent to the tuning frequency of the throttling passage 48, fluid flow is actively generated in the throttling passage 48 in a resonant state, thereby achieving a vibration damping effect based on fluid flow.

[0103] The engine mount 10 applies a magnetic field of intensity corresponding to the input vibration to the magnetic functional fluid within the throttling passage 48, thereby changing the tuning frequency of the throttling passage 48. Specifically, the viscosity of the magnetic functional fluid increases depending on the intensity (magnetic flux density) of the applied magnetic field. Therefore, by controlling the energization of the coil 50, the intensity of the magnetic field can be controlled, thereby adjusting the viscosity of the magnetic functional fluid. Thus, by controlling the intensity of the magnetic field applied to the magnetic functional fluid within the throttling passage 48, the tuning frequency of the throttling passage 48 can be changed even when the cross-sectional area and length of the throttling passage 48 are constant. Therefore, effective vibration damping performance can be obtained for a wider frequency band of vibrations.

[0104] In this embodiment, a magnetic gap 68 is provided in the inner peripheral magnetic circuit 64 of the yoke 52 that guides the magnetic flux, and the magnetic gap 68 is aligned axially with the throttling passage 48. Therefore, when the coil 50 is energized, a magnetic field is efficiently applied from the magnetic poles formed on both sides of the magnetic gap 68 to the magnetic functional fluid within the throttling passage 48, thereby enabling effective modification of the characteristics. The inner peripheral magnetic circuit 64 with the magnetic gap 68 extends axially from the inner peripheral ends of the bottom walls 62, 62. Therefore, the axial position of the magnetic gap 68 in the inner peripheral magnetic circuit 64 has a high degree of freedom, and the position of the end of the inner peripheral magnetic circuit 64 with magnetic poles on the magnetic gap 68 side can be set to the axial position of the throttling passage 48 with a large degree of freedom. Therefore, for example, the end of the inner peripheral magnetic circuit 64 with magnetic poles can be positioned sufficiently close to the throttling member 34, thereby allowing the magnetic flux to pass efficiently from the throttling member 34 to the throttling passage 48.

[0105] Figure 6A suspension bushing 90 for a motor vehicle is shown as a second embodiment of a fluid-sealed vibration damping device configured according to the present invention. The suspension bushing 90 has a configuration in which a magnetic unit 94 is mounted on the bushing body 92. Similar to the engine mount 10 of the first embodiment, by controlling the magnetic field applied from the magnetic unit 94 to the magnetic functional fluid within the throttling passage 48, characteristics such as vibration damping characteristics and support stiffness can be altered. In the following description, sometimes the same reference numerals are used to denote components and parts substantially the same as those in the first embodiment, and descriptions are omitted.

[0106] The bushing body 92 is positioned as follows: on one side of the throttling member 34 in the axial direction ( Figure 6 The outer cylinder component 18 is offset to the left and positioned at the axial center of the outer cylinder component 18, and the throttling passage 48 is offset from the axial center of the outer cylinder component 18 and is positioned to one side of the axial direction.

[0107] The magnetic unit 94 has a configuration in which a coil 50 is disposed inside a yoke 96 having a generally rectangular cross-sectional shape. The coil 50 is disposed on the outer periphery of one axial end of the outer cylinder member 18. The magnetic unit 94 is disposed on the other axial side, which is closer to the axial center of the outer cylinder member 18 than to the axial center of the outer cylinder member 18. Figure 6 The magnetic unit 94 protrudes further axially to the opposite side than the magnetic gap portion 68 on the opposite side of the axial direction. The magnetic unit 94 is disposed at a position on the opposite side of the axial direction, offset from the axial center of the inner circumferential magnetic circuit 64, and is axially aligned with the throttling passage 48, located on the outer circumference of the throttling passage 48. Furthermore, the magnetic gap portion 68 is disposed at a position that is axially away from the coil 50.

[0108] Even though the throttling passage 48 is axially offset from the center of the outer cylinder member 18, the magnetic gap portion 68 is positioned off-axis from the center of the outer cylinder member 18, and the throttling passage 48 and the magnetic gap portion 68 are axially aligned. Therefore, the magnetic field generated by energizing the coil 50 can be efficiently applied to the magnetic functional fluid within the throttling passage 48. Similar to the first embodiment described above, the magnetic gap portion 68 is located midway along the axially extending inner circumferential magnetic circuit 64. Due to the large degree of freedom in setting its axial position, it can be precisely positioned within the throttling passage 48, thereby enabling the magnetic field to effectively act on the magnetic functional fluid within the throttling passage 48. In particular, in this embodiment, the yoke 96 extends further axially than the coil 50 to the opposite side (the connecting arm 98 side described later). Therefore, the position and size of the magnetic gap portion 68 in the yoke 96 can be set with a large degree of freedom, without being constrained by the arrangement of the coil 50. As a result, for example, it is easy to set the magnetic gap 68 corresponding to the axial position and axial width of the throttling passage 48, thereby increasing the degree of design freedom.

[0109] A connecting rod arm 98, serving as a vibration-damping connection member, is mounted on an outer cylinder member 18 that protrudes axially to the opposite side from the magnetic unit 94. The connecting rod arm 98 has a cylindrical mounting portion 100 at its end, which is mounted on the outer peripheral surface of the outer cylinder member 18. In summary, in this embodiment, the magnetic unit 94 is mounted approximately at half the axial direction of the outer cylinder member 18, and the connecting rod arm 98 is mounted at the other approximately half the axial direction of the outer cylinder member 18. The cylindrical mounting portion 100 of the connecting rod arm 98 is mounted on the outer cylinder member 18 at a position axially offset from the magnetic unit 94, thus achieving a smaller diameter compared to the case where it is positioned on the outer periphery of the magnetic unit 94.

[0110] In this way, the external mounting component installed on the outer peripheral surface of the outer cylinder member is not necessarily limited to a component sandwiched between the vibration damping connection object component (body 84) and the outer cylinder member 18, such as the mounting bracket 72 in the above embodiment. It can also be constructed through a part of the vibration damping connection object component (link arm 98). In this case, the vibration damping connection object component is directly installed on the mounting portion 70 of the outer cylinder member 18 without the aid of other components, thereby realizing the connection between the outer cylinder member 18 and the vibration damping connection object component. In addition, in the first embodiment described above, the mounting bracket 72 is arranged at the axial central portion of the magnetic unit 14 including the yoke 52 and passes through a part of the yoke 52. However, the mounting bracket and the vibration damping connection object component installed on the outer peripheral surface of the outer cylinder member 18 can also be arranged to be axially away from or adjacent to the magnetic unit. Furthermore, in this embodiment, although the connecting arm 98, which includes the cylindrical assembly portion 100, is formed of a non-magnetic material, and the connecting arm 98 is configured to be adjacent to the yoke 96 in the axial direction, the magnetic flux guided by the yoke 96 is difficult to escape to the connecting arm 98. Nevertheless, the connecting arm 98 can be formed of a magnetic material when the yoke 96 and the connecting arm 98 are configured to be sufficiently separated.

[0111] In a configuration where a magnetic unit 94 is mounted on a portion of the outer cylinder member 18 along the axial direction, as in the suspension bushing 90 of this embodiment, and an external mounting member is mounted on the other portion of the outer cylinder member 18 that protrudes axially from the magnetic unit 94 along the axial direction, the external mounting member may be a mounting bracket rather than a vibration damping connection member (link arm 98), and the outer cylinder member 18 may be connected to a vibration damping connection member such as a link arm via the mounting bracket.

[0112] The embodiments of the present invention have been described in detail above, but the present invention is not limited to this specific description. For example, the number of coils 50 in the magnetic unit 14 may be three or more. For example, by placing two coils 50 wound on the spool 56 on opposite sides of the mounting cylinder 74 of the mounting bracket 72, the total number of turns of the multiple coils 50 can be adjusted by the combination of the coils 50 obtained through standardization, thereby adjusting the maximum strength of the magnetic field formed by these multiple coils 50.

[0113] The arrangement of the two fastening plates 78, 78 shown in the first embodiment above is merely an example and can be appropriately modified. Specifically, for example, the two fastening plates may extend to the same side in the left-right direction or extend radially in mutually orthogonal directions. In addition, there may be only one fastening plate or more than three. Furthermore, the mounting portion of the mounting bracket to the vibration-damping connection member is not necessarily limited to a plate shape like the fastening plate 78, but may be block-shaped, column-shaped, cylindrical, etc., and may be equivalent to inserting bolts for fastening into the mounting cylinder 74.

[0114] In the above embodiments, a cylindrical vibration damping device is exemplified as a fluid-sealed vibration damping device according to the present invention. For example, the structure of the present invention can be applied to a so-called bowl-shaped vibration damping device, wherein the inner component of the bowl-shaped vibration damping device is arranged on one axial side of the outer cylindrical component, and a plurality of fluid chambers are arranged side by side on the other axial side of the inner component.

[0115] The first embodiment described above exemplifies an engine mount 10, and the second embodiment described above exemplifies a suspension bushing 90. However, the fluid-sealed vibration damping device according to the present invention can be applied within the same scope as existing fluid-sealed vibration damping devices, such as differential mounts.

Claims

1. A fluid-enclosed anti-vibration device (10), The inner component (16) and the outer cylinder component (18) are connected by the main body rubber elastomer (20), and Multiple fluid chambers (46) filled with magnetic functional fluid are disposed inside the fluid-sealed vibration damping device (10). The fluid-sealed vibration damping device (10) is provided with a throttling passage (48) that connects these multiple fluid chambers (46) to each other. A magnetic unit (14) that applies a magnetic field to the magnetic functional fluid in the flow path (48) is disposed in the outer cylinder component (18) in an outer sleeve state. in, The magnetic unit (14) comprises: The magnetic field generating unit (50) generates a magnetic field by energizing it; and The magnetic circuit forming section (52) induces the magnetic flux of the magnetic field generated by the magnetic field generating section (50). A magnetic gap (68) disposed in the magnetic circuit forming section (52) is located on the outer periphery of the throttling passage (48). A magnetic field is applied from the magnetic gap (68) to the magnetic functional fluid within the throttling passage (48). A mounting part (70) is provided on the outer peripheral surface of the outer cylinder member (18) at a position axially offset from the magnetic field generating part (50). The mounting part (70) is equipped with an external assembly member that connects the outer cylinder member (18) to the vibration damping connection object member (84). The outer assembly component is formed as a mounting bracket (72) that connects the outer cylinder component (18) to the vibration damping connection component (84). The mounting bracket (72) installed on the outer cylinder component (18) passes through the magnetic circuit forming part (52).

2. The fluid-sealed vibration damping device (10) according to claim 1, wherein, The magnetic circuit forming section (52) includes: An inner circumferential magnetic circuit (64) extends axially along the inner circumferential side of the magnetic field generating portion (50); and The outer peripheral magnetic circuit (66) extends axially on the outer peripheral side of the magnetic field generating part (50). The magnetic gap portion (68) of the magnetic circuit forming portion (52) is formed in the inner peripheral magnetic circuit (64) of the magnetic circuit forming portion (52), and The mounting bracket (72) protrudes outward through the outer peripheral magnetic circuit (66) of the magnetic circuit forming part (52).

3. The fluid-sealed vibration damping device (10) according to claim 1 or 2, wherein, The plurality of magnetic field generating parts (50) are arranged on both sides of the mounting part (70) of the outer cylinder member (18) in the axial direction.

4. The fluid-sealed vibration damping device (10) according to claim 1 or 2, wherein, The magnetic circuit forming part (52) is formed by two groove-shaped metal parts (54) arranged facing each other and formed into concave shapes that open toward the axial inward side. The magnetic field generating part (50) is disposed on the inner side of each of the groove-shaped metal parts (54), and The magnetic gap (68) is provided between the inner peripheral walls (58) of the two groove-shaped metal parts (54).

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