LIQUID-FILLED ANTI-VIBRATION DEVICE

Abstract

Liquid-filled anti-vibration device (10) comprising: an inner member (16), an outer cylindrical member (18) and a rubber-elastic main body (20), wherein the inner member (16) and the outer cylindrical member (18) are connected by the rubber-elastic main body (20); a plurality of fluid chambers (46) provided inside and filled with a magnetic functional fluid; a throttle channel (48) which allows the fluid chambers (46) to communicate with each other; and a magnetic unit (14) which applies a magnetic field to the magnetic functional fluid in the throttle channel (48) and is provided in an externally inserted state with respect to the outer cylindrical member (18), wherein the magnetic unit (14) comprises: a magnetic field generating part (50) that generates a magnetic field by being supplied with energy; and a magnetic path forming part (52) that induces a magnetic flux of the magnetic field generated by the magnetic field generating part (50), a magnetic gap part (68) provided in the magnetic path forming part (52) is arranged on an outer periphery of the throttle channel (48), and the magnetic field from the magnetic gap part (68) is applied to the magnetic functional fluid in the throttle channel (48), and on an outer peripheral surface of the outer cylindrical member (18), an installation part (70) on which an outer mounting element (72) realizing a connection between the outer cylindrical member (18) and a vibration-damping connection target element is installed is provided at a position axially offset from the magnetic field generating part (50), characterized in that the outer mounting member (72) is an installation bracket connecting the outer cylindrical member (18) to the vibration-damping connection target member, and the installation bracket (72) attached to the outer cylindrical member (18) penetrates through the magnetic path forming part (52).

Description

field of technology

[0001] The disclosure relates to an anti-vibration device or a vibration isolator or a vibration-damping device suitable for an engine mount or an engine mount of a motor vehicle, and more particularly relates to a fluid-filled anti-vibration device that exerts a vibration-damping effect by utilizing a flow behavior of a fluid filled therein. Technical background

[0002] A fluid-filled anti-vibration device is conventionally known, which is used in an engine mount, a differential bearing, etc. of an automobile. German Patent Publication DE 10 2011 117 749 A1 (Patent Document 1) discloses a fluid-filled anti-vibration device having a configuration in which an inner member and an outer cylindrical member are elastically connected by a rubber-elastic main body, a plurality of fluid chambers are provided inside, and a throttle channel is provided through which the fluid chambers communicate with each other. When the filled fluid flows between the fluid chambers through the throttle channel, the fluid-filled anti-vibration device exerts a vibration-damping effect based on the flow behavior of the fluid.

[0003] Furthermore, Patent Document 1 proposes using a magnetorheological fluid as the fluid filled in the fluid chambers, the rheological degree of which changes depending on the magnitude of an applied magnetic field. The fluid-filled anti-vibration device of Patent Document 1 includes a magnetic unit that generates a magnetic field by energizing it and is capable of changing the flow characteristics of the magnetorheological fluid by applying the magnetic field generated by the magnetic unit to the magnetorheological fluid. Furthermore, in the fluid-filled anti-vibration device of Patent Document 1, the flowability (rheological degree) of the magnetorheological fluid is controlled by controlling the strength of the magnetic field applied to the magnetorheological fluid by the magnetic unit.Since the properties such as damping or support stiffness are changed, excellent vibration damping or differential gear support can be achieved.

[0004] The document DE 10 2011 117 749 A1 discloses a differential gear bearing system with a bearing in which a magnetorheological fluid is accommodated and which has a device by means of which a magnetic field acting on the magnetorheological fluid can be provided and the operating parameters of the bearing can be changed.

[0005] Document CN 1 07 06 061 603 B discloses a multi-stage closed-loop and closed-loop control vibration isolator with bypass damping control. A damping bypass loop structure is added to a traditional magnetorheological vibration isolator, and a previously single-stage magnetic field operating range is transformed into a multi-stage controllable magnetic field.

[0006] The document DE 101 17 817 A1 discloses a device for damping or suppressing vibrations in a moving system, in particular a vehicle drive unit, in the form of an assembly bearing or a damper, which has a chamber filled with a magnetorheological fluid in which a magnetic field can be generated. [Prior art documents][Patent documents]

[0007] [Patent document 1] DE 10 2011 117 749 A1 Summary of the inventionProblem to be solved by the invention

[0008] However, if the Fig. 4 of Patent Document 1 is to be arranged inside the liquid-filled anti-vibration device, it is necessary to provide a liquid-tight sealing structure so that the energized magnetic unit does not come into contact with the filled liquid, and the configuration is likely to become complicated. Therefore, as shown in the Fig. 2 and Fig. 3 of Patent Document 1, the magnetic unit may be configured to be installed on the outer peripheral surface of the outer cylindrical member.

[0009] However, when the magnetic unit is installed on the outer peripheral surface of the outer cylindrical member, an outer mounting member that establishes the connection between a vibration-damping connection target member and the outer cylindrical member is arranged on a further outer periphery of the magnetic unit in the installation portion of the outer cylindrical member, and the increase in the size of the installation portion of the outer cylindrical member is likely to become a problem.

[0010] The object to be achieved by the invention is to provide a liquid-filled anti-vibration device having a novel configuration capable of controlling the characteristics by applying a magnetic field to a magnetic functional fluid, while being capable of suppressing the increase in size of the outer mounting member connecting the outer cylindrical member and the vibration-damping connection target member. Means to solve the problem

[0011] The following describes exemplary embodiments for understanding the disclosure, but each of the embodiments described below is described as an exemplary example and may be used in combination with others, if appropriate. Several components described in each aspect may also be recognized and adopted independently of each other to the extent possible, and they may also be adopted in combination with any component described in another aspect. Accordingly, the disclosure may be implemented in various alternatives without being limited to the embodiments described below.

[0012] A first aspect provides a fluid-filled anti-vibration device in which an inner member and an outer cylindrical member are connected by a rubber-elastic main body, a plurality of fluid chambers in which a magnetic functional fluid is encapsulated are provided inside, a throttle channel that allows the fluid chambers to communicate with each other is provided, and a magnetic unit that applies a magnetic field to the magnetic functional fluid in the throttle channel is provided in an externally inserted state with respect to the outer cylindrical member. The magnetic unit includes: a magnetic field generating part that generates a magnetic field by being supplied with energy; and a magnetic path forming part that induces a magnetic flux of the magnetic field generated by the magnetic field generating part.A magnetic gap part provided in the magnetic path forming part is arranged on an outer periphery of the throttle channel, and the magnetic field is applied from the magnetic gap part to the magnetic functional fluid in the throttle channel. On an outer peripheral surface of the outer cylindrical member, an installation part, on which an outer mounting member connecting the outer cylindrical member and a vibration-damping connection target member is installed, is provided at a position axially offset from the magnetic field generating part.

[0013] According to the fluid-filled anti-vibration device configured according to the aspect, by applying the magnetic field formed by the magnetic unit installed on the outer peripheral surface of the outer cylindrical member to the magnetic functional fluid encapsulated in the fluid chamber, the vibration damping properties or vibration isolation properties, and properties such as support rigidity of a power unit or a differential gear can be changed. Specifically, by controlling the strength of the magnetic field applied to the magnetic functional fluid by the magnetic unit, the properties of the fluid-filled anti-vibration device can be regulated and adjusted, and excellent properties can be achieved.In addition, since the magnetic unit is installed on the outer peripheral surface of the outer cylindrical member, the magnetic unit does not come into contact with the magnetic functional fluid encapsulated in the fluid chambers, and the assembly configuration is simplified.

[0014] The mounting portion of the outer cylindrical member, where the outer mounting member, such as the installation bracket or the vibration-damping joint target, is installed, is set to be axially offset from the magnetic field generating part, such as the coil constituting the magnetic unit. Accordingly, the diameter of the installation portion of the outer mounting member on the outer cylindrical member can be reduced compared to the case where the outer mounting member is arranged on the outer periphery of the magnetic field generating part.

[0015] According to the invention, in the liquid-filled anti-vibration device, the outer mounting member is an installation bracket that connects the outer cylindrical member to the vibration-damping connection target member, and the installation bracket installed on the outer cylindrical member penetrates through the magnetic path forming part.

[0016] According to the liquid-filled anti-vibration device configured according to the aspect, a large degree of freedom for the arrangement of the magnetic path forming part can be achieved while the installation bracket is installed on the outer peripheral surface of the outer cylindrical member at a position facing away from the magnetic field generating part in the axial direction.

[0017] According to a second aspect, in the liquid-filled anti-vibration device, the magnetic path forming part includes an inner circumferential magnetic path extending along an inner peripheral side of the magnetic field generating part in the axial direction, and an outer circumferential magnetic path extending along an outer peripheral side of the magnetic field generating part in the axial direction. Furthermore, the magnetic gap part of the magnetic path forming part is formed on the inner circumferential magnetic path of the magnetic path forming part, and the installation bracket penetrates the outer circumferential magnetic path of the magnetic path forming part and protrudes toward an outer periphery.

[0018] According to the fluid-filled anti-vibration device configured in accordance with the aspect, with the magnetic gap portion formed in the inner peripheral magnetic path, the magnetic field can be efficiently applied from the magnetic gap portion to the magnetic functional fluid encapsulated in the inner peripheral side of the outer cylindrical member. Furthermore, when the installation bracket penetrates the outer peripheral magnetic path, for example, a fixing portion of the installation bracket to the vibration-damping connection target member can protrude toward the outer periphery from the magnetic path forming portion.

[0019] According to a third aspect, in the liquid-filled anti-vibration device as set forth in any one of the first and second aspects, a plurality of magnetic field generating parts are arranged on two sides with respect to the fitting part of the outer cylindrical member in the axial direction.

[0020] According to the fluid-filled anti-vibration device configured in accordance with the aspect, by adjusting the installation position of the outer mounting member on the outer cylindrical member between the magnetic field generating parts in the axial direction, for example, it is easy to install the outer mounting member in a position near the center in the axial direction with respect to the outer cylindrical member. Furthermore, by providing the magnetic field generating parts on both sides of the installation position of the outer mounting member on the outer cylindrical member in the axial direction, the magnetic field generating parts can be arranged with excellent space efficiency, and it is possible to increase the degree of freedom for adjusting the magnetic field formed by the magnetic field generating parts.

[0021] According to a fourth aspect, in the liquid-filled anti-vibration device as set forth in any one of the first to third aspects, the magnetic path forming part is formed by two groove-like metal fittings open in a concave shape to an inner side in the axial direction and facing each other, the magnetic field generating part is arranged on an inner side of each of the groove-like metal fittings, and the magnetic gap part is provided between inner peripheral wall parts of the two groove-like metal fittings.

[0022] According to the liquid-filled anti-vibration device configured in accordance with the aspect, the magnetic unit in which the magnetic path forming part is provided on the periphery of the magnetic field generating part can be easily obtained. Furthermore, by separating the inner peripheral side wall portions of the two groove-like metal fittings that oppose each other in the axial direction, the magnetic gap can be easily provided between the inner peripheral wall portions of the two groove-like metal fittings. Effect of the invention

[0023] According to the disclosure, the liquid-filled anti-vibration device is capable of controlling the characteristics by applying a magnetic field to the magnetic functional liquid while suppressing the enlargement of the installation portion of the outer mounting member on the outer cylindrical member connecting the outer cylindrical member and the vibration-damping connection target member. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view showing an engine mount in a first embodiment of the disclosure. Fig. 2 is a cross-sectional view of the Fig. 1 and corresponds to a II-II cross-section of Fig. 3. Fig. 3 is a cross-sectional view of III-III from Fig. 2. Fig. Fig. 4 is a perspective view showing a state in which an opening member is attached to an integrally vulcanized molded part of a rubber elastic main body which forms the engine mount of Fig. 1 forms. Fig. 5 is a front view of an opening element that opens the motor mount of Fig. 1 forms. Fig. 6 is a cross-sectional view showing an engine mount as a second unclaimed embodiment of the disclosure. DESCRIPTION OF THE EMBODIMENTS

[0024] In the following, the embodiments of the disclosure will be described with reference to the drawings.

[0025] In the Fig. 1 to 3, an engine mount 10 of a motor vehicle is shown as a first embodiment of a fluid-filled anti-vibration device configured according to the disclosure. The engine mount 10 has a structure in which a magnetic unit 14 is installed on a bearing body 12. The bearing body 12 has a structure in which an inner member 16 and an outer cylindrical member 18 are connected by a rubber-elastic main body 20. In the following descriptions, the top-bottom direction basically refers to the top-bottom direction in Fig. 2, the left-right direction to the left-right direction in Fig. 2 and the front-back direction to the left-right direction in Fig. 1, which is an axial direction.

[0026] The inner member 16 is configured as a high-rigidity member formed in a substantially cylindrical shape and extending linearly using metal, synthetic resin, etc. The inner member 16 can be made of a non-magnetic material such as stainless steel, synthetic resin, etc. A stopper member 22 is attached to the axial center of the inner member 16. The stopper member 22 is inserted from the outside of the inner member 16 and protrudes in the radial direction (upper / lower direction) to two sides.

[0027] An intermediate sleeve 24 is arranged on the outer peripheral side of the inner member 16. The intermediate sleeve 24 has a substantially cylindrical shape with a diameter larger than that of the inner member 16 and is arranged so that it can be inserted into the inner member 16 from the outside. The intermediate sleeve 24 can be made of a non-magnetic material such as stainless steel or synthetic resin. The intermediate sleeve 24 includes a pair of window parts 26, 26 on two sides (the upper and lower directions in Fig. 2) in the radial direction. The window portion 26 extends in the circumferential direction with a length of less than half the circumference and penetrates the intermediate sleeve 24 in the upper and lower directions. Groove-like portions 28, 28 are formed in the circumferential direction of the intermediate sleeve 24 between the window portions 26, 26. The groove-like portion 28 is located in the central portion of the intermediate sleeve 24 in the axial direction and is provided to extend in the circumferential direction as a concave cross-section open to the outer peripheral surface.

[0028] The inner member 16 and the intermediate sleeve 24 are elastically connected to each other by the rubber-elastic main body 20. The rubber-elastic main body 20 has a thick, substantially cylindrical shape as a whole, the inner peripheral surface of the rubber-elastic main body 20 is fixed to the inner member 16, and the outer peripheral surface of the rubber-elastic main body 20 is fixed to the outer cylindrical member 18. The rubber-elastic main body 20 of the embodiment is formed as an integrally vulcanized molded article including the inner member 16 and the intermediate sleeve 24, and the inner member 16 and the intermediate sleeve 24 are vulcanized and bonded to the rubber-elastic main body 20. Furthermore, by reducing the diameter of the intermediate sleeve 24 in the radial direction by performing a diameter-reducing process such as eight-way squeezing, etc.after the rubber-elastic main body 20 is formed, the tensile stress due to cooling shrinkage after forming the rubber-elastic main body 20 can be reduced.

[0029] The rubber-elastic main body 20 includes a pair of pocket parts 30, 30 which are formed on two sides in one direction (the upper-lower direction in Fig. 2) are open in the radial direction. The pocket part 30 has an opening shape corresponding to the window part 26, an opening peripheral part is fixed to the intermediate sleeve 24, and the pocket part 30 is open to the outer periphery via the window part 26 in the integrally vulcanized molded part of the rubber-elastic main body 20. The stop member 22 attached to the inner member 16 projects in the radial direction from the inner peripheral side to the outer peripheral side and into each pocket part 30.

[0030] The inner surfaces of the groove-like parts 28, 28 of the intermediate sleeve 24 are each covered with a rubber fitting 32 which is formed integrally with the rubber-elastic main body 20. In addition, as shown in Fig. 4, opening elements 34, 34 are attached to the groove-like parts 28, 28. The opening element 34 has a substantially semi-cylindrical shape extending in the circumferential direction with a length of less than half the circumference and is arranged to span the window part 26 in the circumferential direction, and two ends of the opening element 34 in the circumferential direction are inserted into the groove-like parts 28, 28. One end of the opening element 34 in the circumferential direction is configured as a narrow part 36 whose dimension in the axial direction is smaller than that of the other portions. As shown in Fig. As shown in Fig. 5, in the narrow part 36 of the opening member 34, a groove 38 is formed in the central portion in the axial direction, which groove is open to the outer peripheral surface and extends in the circumferential direction. Furthermore, in another portion of the opening member 34 outside the narrow part 36 in the circumferential direction, an opening part 40 is provided, which has a larger dimension in the axial direction than the groove 38 and penetrates in the radial direction. In the opening part 40, the width of the end on the groove 38 side in the circumferential direction is gradually reduced in the axial direction toward the groove 38, and the groove 38 and the opening part 40 are continuous in the circumferential direction. The opening member 34 is formed of a ferromagnetic material such as iron, nickel, chromium, soft ferrite, etc.

[0031] The two opening members 34, 34 are arranged to oppose each other in the radial direction and are installed on the intermediate sleeve 24 in a state where the narrow parts 36, 36 are inserted into one of the groove-like parts 28 from two circumferential sides. The circumferential ends of the two opening members 34, 34 on the side opposite to the narrow parts 36, 36 are inserted into the other groove-like part 28 from two circumferential sides, and a separating rubber 42 is arranged between the circumferential ends on the side opposite to the narrow parts 36, 36, protruding from the rubber fitting 32 toward the outer periphery.Since the two ends of each of the opening members 34, 34 are inserted into the groove-like parts 28, 28 in the circumferential direction, each of the opening members 34, 34 is arranged to span each of the window parts 26, 26 in the circumferential direction, and the opening part 40 is communicated with the pocket part 30 through the window part 26.

[0032] The outer cylindrical member 18 is attached to the integrally vulcanized molding of the rubber-elastic main body 20. The outer cylindrical member 18 has a substantially cylindrical shape with a diameter larger than that of the intermediate sleeve 24 and can be made of a non-magnetic material such as stainless steel or synthetic resin. The outer cylindrical member 18 has its inner peripheral surface covered with a sealing rubber layer 44. By performing a diameter reduction on the outer cylindrical member 18 in a state where it is inserted from the outside into the intermediate sleeve 24 to which the orifice members 34, 34 are attached, the inner peripheral surface of the outer cylindrical member 18 covered with the sealing rubber layer 44 is pressed against the outer peripheral surface of the intermediate sleeve 24, and the outer cylindrical member 18 is fixed to the intermediate sleeve 24.Since the sealing rubber layer 44 is arranged in a compressed state, the overlapping surfaces of the outer cylindrical member 18 and the intermediate sleeve 24 are sealed in a fluid-tight manner. It should be noted that the overlapping areas between the outer cylindrical member 18 and the opening members 34, 34 can also be filled in a fluid-tight manner by using the sealing rubber layer 44.

[0033] The window portions 26, 26 are covered by the outer cylindrical member 18, and the outer peripheral openings of the pocket portions 30, 30 are sealed by the outer cylindrical member 18 in a fluid-tight manner. Accordingly, two fluid chambers 46, 46 are formed inside the motor mount 10. A magnetic functional fluid is filled into each fluid chamber 46. The magnetic functional fluid is a fluid whose rheological degree is increased by the action of a magnetic field. The magnetic functional fluid can be a magnetorheological fluid (MRF), a magnetic fluid (MF), or a magnetic composite fluid (MCF) that mixes MRF and MF.As a magnetic functional fluid, an MRF can be used, the rheological degree of which changes significantly with respect to the action of a magnetic field, and an MCF, the magnitude of the increase in the rheological degree of which can be easily adjusted according to the mixing ratio between MRF and MF.

[0034] The magnetic functional fluid is, for example, a suspension or a colloidal solution in which ferromagnetic fine particles are dispersed in a base fluid such as water, oil, etc. The surfaces of the fine ferromagnetic particles are coated with a surfactant, or the fine ferromagnetic particles are dispersed in a base fluid with the addition of a surfactant, so that it is difficult for the fine ferromagnetic particles to aggregate or settle in the base fluid.

[0035] The ferromagnetic fine particles are metal particles such as iron, ferrite, magnetite, etc., and the particle diameter can range from about 8 nm to about 10 μm. There are no particular restrictions on the base liquid as long as the fine ferromagnetic particles can be dispersed. For example, water, isoparaffin, alkyl naphthalene, perfluoropolyether, polyolefin, silicone oil, etc. can be used. In addition, the base liquid can be an incompressible liquid. The surfactant can be selected according to the base liquid, for example, oleic acid, etc. can be used. MRF and MF mainly differ in the particle diameter of the ferromagnetic fine particles. The particle diameter of the ferromagnetic fine particles in MRF is larger than that of MF.

[0036] The fluid chambers 46 and 46 communicate with each other through a throttle channel 48. The throttle channel 48 is formed by covering and blocking the outer peripheral openings of the grooves 38, 38 of the orifice members 34, 34 using the outer cylindrical member 18. The throttle channel 48 extends in the circumferential direction between the fluid chambers 46, 46 in the circumferential direction, and two ends of the throttle channel 48 in the circumferential direction communicate with the fluid chambers 46, 46. By adjusting a ratio between the path cross-section and the path length while taking into account the wall spring stiffness of the fluid chambers 46, 46 and the rheological degree of the magnetic functional fluid, the tuning frequency, which is the resonance frequency of the flowing fluid, is adjusted in accordance with the vibration frequency of the vibration damping target.

[0037] It should be noted that in this embodiment, the throttle channel 48 is provided between the fluid chambers 46, 46 in the circumferential direction. However, the throttle channel can also be provided, for example, to extend the opening of the pocket part 30 in the circumferential direction. In this way, a longer path length can be ensured. The path with such a length is realized, for example, by forming the groove 38 over a larger area in the circumferential direction in the opening element 34 and reducing the length of the opening part 40 in the circumferential direction.

[0038] The magnetic unit 14 is mounted on the bearing body 12. The magnetic unit 14 includes coils 50 as a magnetic field generating part and a yoke 52 as a magnetic path forming part. Specifically, the magnetic unit 14 of the embodiment has a structure in which two coils 50, 50 are arranged on the inner sides of two groove-like metal fittings 54, 54, and the two groove-like metal fittings 54, 54 are opposed to each other to open toward the inner side in the axial direction.

[0039] Coil 50 consists of a conductive metal wire and is wound around a non-magnetic coil former 56. Coil 50 is connected to an external power supply via a connector (not shown here) provided in coil former 56. Supplying current to coil 50 generates a magnetic field around coil 50.

[0040] The grooved metal fitting 54 is annular and continuous in the circumferential direction, has a cross-sectional shape of a concave groove open toward the inside in the axial direction, and has a configuration in which each cylindrical inner peripheral wall portion 58 and outer peripheral wall portion 60 are connected by a lower wall portion 62 at an outer end in the axial direction. The grooved metal fitting 54 is formed of a ferromagnetic material such as iron, nickel, chromium, soft ferrite, etc. The coil 50, which is arranged between the inner peripheral wall portion 58 and the outer peripheral wall portion 60 in the grooved metal fitting 54, rests on the lower wall portion 62 of the grooved metal fitting 54 from the inside in the axial direction.

[0041] The two groove-like metal fittings 54, 54, in each of which the coil 50 is arranged on the inside, face each other in the axial direction, the outer peripheral wall parts 60, 60 abut each other in the axial direction, and the inner peripheral wall parts 58, 58 are separated from each other in the axial direction. In this way, the yoke 52 is formed by the groove-like metal fittings 54, 54 by arranging the two groove-like metal fittings 54, 54 so that they face each other. In the embodiment, an inner peripheral magnetic path 64 of the yoke 52 is formed by the inner peripheral wall parts 58, 58 of the groove-like metal fittings 54, and an outer peripheral magnetic path 66 of the yoke 52 is formed by the outer peripheral wall parts 60, 60 of the groove-like metal fittings 54.The coil 50 is arranged on the inside of the groove-like metal fitting 54, the inner circumferential magnetic path 64 is provided to extend in the axial direction on the inner circumferential side of the coil 50, and the outer circumferential magnetic path 66 is provided to extend in the axial direction on the outer circumferential side of the coil 50. In the inner circumferential magnetic path 64 of the yoke 52, a magnetic gap part 68 is formed between the inner circumferential wall parts 58, 58 in the axial direction. Moreover, the magnetic flux of the magnetic field formed on the circumference of the coil 50 by the power supply to the coil 50 is induced by the yoke 52, and the magnetic field is efficiently applied to the outside at the magnetic gap part 68.Although the outer peripheral wall parts 60, 60 abut each other in the axial direction in the embodiment, the outer peripheral wall parts 60, 60 may also be separated from each other by a separation distance shorter than the magnetic gap part 68, for example.

[0042] The magnetic unit 14 is attached to the outer peripheral surface of the outer cylindrical member 18. That is, by externally attaching the inner peripheral magnetic path 64 of the yoke 52 to the outer peripheral surface of the outer cylindrical member 18, the magnetic unit 14 is fixed to the outer cylindrical member 18 in an externally inserted state. In the state where the magnetic unit 14 is fixed to the outer cylindrical member 18, the coils 50, 50 are arranged on the outer periphery of the two ends of the outer cylindrical member 18 in the axial direction. In the embodiment, the coils 50, 50 are arranged to protrude from the outer cylindrical member 18 to the outside in the axial direction. Moreover, the magnetic gap part 68 of the yoke 52 is located at the central portion of the outer cylindrical member 18 in the axial direction and is arranged on the outer periphery of the throttle channel 48.In short, the magnetic gap part 68 and the throttle channel 48 are aligned with each other in the axial direction. By disposing the magnetic gap part 68 near the throttle channel 48, the magnetic field generated by the coils 50, 50 is guided through the yoke 52 and applied from the magnetic gap part 68 to the magnetic functional fluid within the throttle channel 48. Furthermore, the magnetic gap part 68 is provided at a position on the inner side in the axial direction and away from the coils 50, 50. The outer peripheral surface of the outer cylindrical member 18 overlaps with the inner peripheral magnetic path 64 and is open to the outer circumference at the magnetic gap part 68. The exposed portion is formed as an installation part 70. The installation part 70 is arranged at a position away from the coils 50, 50 in the axial direction and is arranged between the coils 50, 50 in the axial direction.That is, on the outer peripheral surface of the outer cylindrical member 18, the coils 50 are installed on the two sides away from the fitting part 70 in the axial direction.

[0043] At the position axially remote from the coils 50, 50 of the magnetic unit 14, an installation bracket 72 is attached as an outer mounting member to the outer peripheral surface of the outer cylindrical member 18. As shown in Fig. 3, the installation bracket 72 includes a cylindrical fitting part 74 arranged in a substantially cylindrical shape and externally fitted and fixed to the outer peripheral surface of the outer cylindrical member 18. In the cylindrical fitting part 74, the inner peripheral surface at the central part in the axial direction has a smaller diameter than the inner peripheral surfaces at both ends, and a protruding fitting part 76 is provided at the central part in the axial direction, protruding toward the inner periphery. The cylindrical fitting part 74 is arranged between the coils 50, 50 in the axial direction, and at a position remote from the coils 50, 50 in the axial direction, the protruding fitting part 76 is fitted into and fixed to the fitting part 70 of the outer peripheral surface of the outer cylindrical member 18.

[0044] Since the installation bracket 72 is attached to the outer peripheral surface of the outer cylindrical member 18 at the position where the cylindrical fitting part 74 is axially spaced from the coils 50, 50 of the magnetic unit 14, the diameter of the cylindrical fitting part 74 is smaller than in a configuration in which the installation bracket 72 is arranged on the outer peripheral sides of the coils 50, 50, and the enlargement of the installation bracket 72 can be avoided.

[0045] As in Fig. 2, gaps are formed between the cylindrical fitting portion 74 and the outer cylindrical member 18 on both sides of the protruding fitting portion 76 in the axial direction, and the inner peripheral wall portions 58, 58 of the magnetic unit 14 are inserted into the gaps. In other words, the installation bracket 72 is installed on the outer cylindrical member 18 by passing the protruding fitting portion 76 of the cylindrical fitting portion 74 through the magnetic gap portion 68 of the yoke 52 and attaching the protruding fitting portion 76 to the fitting portion 70 of the outer peripheral surface of the outer cylindrical member 18. The installation bracket 72 is made of a non-magnetic material such as stainless steel or synthetic resin, and even if the installation bracket 72 is disposed near the magnetic gap portion 68, it is difficult for the magnetic flux to escape from the yoke 52 to the installation bracket 72.

[0046] The Fig. The installation bracket 72 shown in Figure 3 includes two fastening parts 78, 78 that protrude from the cylindrical fitting part 74 toward the outer peripheral side. The fastening part 78 has the shape of a substantially rectangular plate and has a bolt hole 80 penetrating through the thickness direction. The two fastening parts 78, 78 protrude from the cylindrical fitting part 74 toward both sides in the left-right direction. The two fastening parts 78, 78 are both spaced apart from the center of the cylindrical fitting part 74 in the upper-lower direction and are provided at positions different from each other in the upper-lower direction. As shown in Figures Fig. 1 and Fig. 3, the fastening pieces 78, 78 protrude from the magnetic unit 14 in the direction of the outer circumference through insertion windows 82, 82 which penetrate the outer circumferential magnetic path 66 of the yoke 52.

[0047] In this way, by configuring the fixing parts 78, 78 of the installation bracket 72 passing through the outer peripheral magnetic path 66 of the yoke 52 and protruding toward the outer periphery, the configuration of the yoke 52 can be prevented from being limited by the installation configuration (installation position) of the installation bracket 72 on the vehicle, and the installation configuration (installation position) of the installation bracket 72 on the vehicle can be prevented from being limited by the configuration of the yoke 52, and a high degree of design freedom can be realized.

[0048] The thus configured engine mount 10 is installed, for example, on the power plant side, which is a vibration-damping connection target member, through an inner bolt (not shown) through which the inner member 16 is inserted. Furthermore, the outer cylindrical member 18 is installed on the vehicle body 84 side, which is another vibration-damping connection target member, via the installation bracket 72 by screwing the two fastening parts 78, 78 to the vehicle body 84 side. Accordingly, the engine (not shown) is supported by the vehicle body 84 with vibration damping by the engine mount 10.

[0049] In the above-described vehicle mounting state, when vibration is generated between the inner member 16 and the outer cylindrical member 18 of the engine mount 10 to cause a relative pressure change between the fluid chambers 46, 46, a fluid flow is generated through the throttle channel 48 between the fluid chambers 46, 46. Specifically, in the case where the frequency of the input vibration and the tuning frequency of the throttle channel 48 are the same, a fluid flow is actively generated in a resonance state in the throttle channel 48, and a vibration damping effect is exerted based on the fluid flow behavior.

[0050] In the engine mount 10, by applying a magnetic field whose strength corresponds to the input vibration to the magnetic functional fluid in the throttle channel 48, the tuning frequency of the throttle channel 48 can be changed. That is, in the magnetic functional fluid, the rheological degree increases depending on the magnitude (magnetic flux density) of the applied magnetic field. In other words, by controlling the power supplied to the coil 50, the strength of the magnetic field is controlled, and the rheological degree of the magnetic functional fluid can be regulated. Accordingly, by controlling the magnitude of the magnetic field applied to the magnetic functional fluid in the throttle channel 48, even if the path cross-sectional area and path length of the throttle channel 48 remain constant, the tuning frequency of the throttle channel 48 can be changed.Therefore, effective vibration damping properties against vibrations in a wider frequency range can be achieved.

[0051] In the embodiment, the magnetic gap portion 68 is provided in the inner circumferential magnetic path 64 of the yoke 52, which guides the magnetic flux, and the magnetic gap portion 68 is aligned with the throttle channel 48 in the axial direction. Accordingly, when the coil 50 is energized, the magnetic field is efficiently applied from the magnetic poles formed on both sides of the magnetic gap portion 68 to the magnetic functional fluid in the throttle channel 48, and the change in the adjustment of the properties can be effectively realized.Since the inner circumferential magnetic path 64, in which the magnetic gap portion 68 is provided, extends in the axial direction from the inner circumferential ends of the lower wall portions 62, 62, the degree of freedom for adjusting the position of the magnetic gap portion 68 in the inner circumferential magnetic path 64 in the axial direction is large, and the position of the end of the inner circumferential magnetic path 64 where the magnetic pole is formed on the magnetic gap portion 68 side can be adjusted with a large degree of freedom with respect to the position of the throttle channel 48 in the axial direction. Accordingly, for example, the end of the inner circumferential magnetic path 64 where the magnetic pole is formed can be arranged to be very close to the opening member 34, and the magnetic flux can efficiently pass from the opening member 34 to the throttle channel 48.

[0052] In Fig. 6 illustrates a suspension bushing 90 of a motor vehicle as a second embodiment of a fluid-filled anti-vibration device configured according to the disclosure. The suspension bushing 90 has a configuration in which a magnetic unit 94 is installed on a bushing body 92. As with the engine mount 10 of the first embodiment, it is possible to change properties such as vibration damping characteristics or bearing rigidity by controlling the magnetic field applied by the magnetic unit 94 to the magnetic functional fluid in a throttle channel 48. Hereinafter, components substantially the same as those of the first embodiment are denoted by the same reference symbols, and their descriptions may be omitted.

[0053] In the socket body 92, the opening member 34 is arranged so as to be directed to one side (the left side in Fig. 6), and the throttle channel 48 is provided at a position away from the center of the outer cylindrical member 18 in the axial direction and offset to one side in the axial direction.

[0054] The magnetic unit 94 has a configuration in which a coil 50 is arranged within a yoke 96 having a space with a substantially rectangular cross section. The coil 50 is arranged on the outer circumference of one end of the outer cylindrical member 18 in the axial direction. The magnetic unit 94 is arranged on one side in the axial direction with respect to the center of the outer cylindrical member 18 in the axial direction, and the other side (the right side in Fig.6) in the axial direction with respect to the center of the outer cylindrical member 18 in the axial direction protrudes toward the other side in the axial direction with respect to the magnetic unit 94. In the magnetic unit 94, the magnetic gap part 68 is provided at a position deviated to the other side in the axial direction with respect to the center of the inner circumferential magnetic path 64 in the axial direction, aligned with the throttle channel 48 in the axial direction, and arranged on the outer peripheral side of the throttle channel 48. Note that the magnetic gap parts 68 are provided at positions deviated to the other side in the axial direction with respect to the coils 50, 50.

[0055] Even if the throttle channel 48 is axially distant from the center of the outer cylindrical member 18, the magnetic gap portion 68 is disposed at a position axially distant from the center of the outer cylindrical member 18, and the throttle channel 48 and the magnetic gap portion 68 are axially aligned. Therefore, a magnetic field generated by supplying current to the coil 50 can be efficiently applied to the magnetic functional fluid in the throttle channel 48. As in the first embodiment, the magnetic gap portion 68 is provided at the center of the axially extending inner circumferential magnetic path 64, and the degree of freedom for adjusting the position in the axial direction is large. Therefore, the magnetic gap portion 68 can be aligned with the throttle channel 48, and the magnetic field can effectively function in the magnetic functional fluid in the throttle channel 48.Specifically, in the embodiment, the yoke 96 can extend toward the other side (the side of a connecting arm 98, which will be described later) of the coil 50. Accordingly, the position and size of the magnetic gap portion 68 in the yoke 96 are not limited by the arrangement of the coil 50 and can be adjusted with a large degree of freedom. As a result, for example, the magnetic gap portion 68 corresponding to the position or width dimension of the throttle channel 48 in the axial direction can be easily adjusted, and the degree of freedom of design is increased.

[0056] The connecting arm 98 as a vibration-damping connecting target member is attached to the outer cylindrical member 18, which protrudes from the magnetic unit 94 to the other side in the axial direction. The connecting arm 98 includes a cylindrical mounting part 100 at one end, and the cylindrical mounting part 100 is attached to the outer peripheral surface of the outer cylindrical member 18. In short, in the embodiment, the magnetic unit 94 is installed on substantially one half of the outer cylindrical member 18 in the axial direction, and the connecting arm 98 is installed on substantially the other half of the outer cylindrical member 18 in the axial direction. The cylindrical mounting part 100 of the connecting arm 98 is attached to the outer cylindrical member 18 at a position away from the magnetic unit 94 in the axial direction.Therefore, the diameter of the cylindrical mounting part 100 can be reduced compared to the case where it is arranged on the outer circumference of the magnetic unit 94.

[0057] In this way, the outer mounting member installed on the outer peripheral surface of the outer cylindrical member is not necessarily limited to a member disposed between the vibration-damping connection target member (vehicle body 84) and the outer cylindrical member 18, such as the installation bracket 72 of the above embodiment, but can also be configured by using a part of the vibration-damping connection target member (connecting arm 98). In this case, the connection between the outer cylindrical member 18 and the vibration-damping connection target member is realized by directly installing the vibration-damping connection target member on the fitting part 70 of the outer cylindrical member 18 without interposing any other member.Furthermore, in the first embodiment, the installation bracket 72 is arranged at the central portion of the magnetic unit 14 including the yoke 52 in the axial direction and penetrates a portion of the yoke 52. However, the installation bracket or the vibration-damping connection target member attached to the outer peripheral surface of the outer cylindrical member 18 may also be arranged to be distant from or adjacent to the magnetic unit in the axial direction. In the embodiment, the connecting arm 98 including the cylindrical mounting part 100 is formed using a non-magnetic material. Even if the connecting arm 98 is arranged to be adjacent to the yoke 96 in the axial direction, it is still difficult for the magnetic flux guided by the yoke 96 to reach the connecting arm 98.It should be noted that in the case where the yoke 96 and the connecting arm 98 are arranged to have a sufficient distance from each other, etc., the connecting arm 98 may also be formed by using a magnetic material.

[0058] In a configuration in which the magnetic unit 94 is installed at one portion of the outer cylindrical member 18 in the axial direction and the outer mounting member is installed at another portion of the outer cylindrical member 18 in the axial direction, which protrudes from the magnetic unit 94 in the axial direction, such as the suspension bushing 90 according to the embodiment, the outer mounting member may also be an installation bracket instead of the vibration-damping connection target member (the connection arm 98), and the outer cylindrical member 18 may also be connected to the vibration-damping connection target member, such as the connection arm, etc., via the mounting bracket.

[0059] Although the embodiments of the disclosure have been described in detail above, the disclosure is not limited to this detailed description. For example, the number of coils 50 of the magnetic unit 14 may be three or more. For example, by arranging two coils 50 wound around the coil body 56 on each of the two sides of the cylindrical mounting portion 74 and the installation bracket 72 in the axial direction, it is possible to regulate the total number of turns of the coils 50 by standardizing the combination of the coils 50 and to regulate the maximum magnitude, etc., of the magnetic field formed by the coils 50.

[0060] The arrangement of the fastening parts 78, 78 shown in the first embodiment is merely an example and can be changed as needed. Specifically, for example, the two fastening parts may extend to the same side in the left-right direction and may also be orthogonal to each other in radial directions. Furthermore, there may be only one fastening part, but there may also be three or more fastening parts. Furthermore, the mounting portion of the mounting bracket for the vibration-damping connection target member is not necessarily limited to being plate-shaped like the fastening part 78, but may also be block-shaped, column-shaped, cylindrical, etc., and a fastening bolt may also be inserted into the cylindrical fitting part 74.

[0061] In the embodiments, a cylindrical anti-vibration device is illustrated as the fluid-filled anti-vibration device according to the disclosure. However, the configuration of the disclosure can also be applied, for example, to a so-called cup-shaped anti-vibration device in which the inner member is arranged on one side of the outer cylindrical member in the axial direction, and a plurality of fluid chambers are arranged axially adjacent to each other on the other side of the inner member in the axial direction.

[0062] In the first embodiment, the engine mount 10 is shown, and in the second embodiment, the suspension bushing 90 is shown. However, the fluid-filled anti-vibration device according to the embodiment can be used to the same extent as the conventional fluid-filled anti-vibration device, for example, on a differential bearing. Explanation of reference symbols 10 Engine mount (first embodiment, liquid-filled anti-vibration device); 12 bearing bodies; 14 magnetic unit; 16 inner element; 18 outer cylindrical element; 20 rubber-elastic main body; 22 stop element; 24 intermediate sleeve; 26 window part; 28 groove-like part; 30 pocket part; 32 rubber fittings; 34 opening element; 36 narrow part; 38 groove; 40 opening part; 42 separating rubber; 44 sealing rubber layer; 46 fluid chamber; 48 throttle channel; 50 Coil (magnetic field generating part); 52 Yoke (magnetic path forming part); 54 grooved metal fitting; 56 coil bodies; 58 inner peripheral wall part; 60 outer peripheral wall part; 62 lower wall part; 64 inner circumferential magnetic path; 66 outer circumferential magnetic path; 68 magnetic gap part; 70 built-in part; 72 Installation bracket (outer mounting element); 74 cylindrical fitting; 76 protruding fitting part; 78 fastening part; 80 bolt hole; 82 insert windows; 84 Vehicle body (vibration damping connection target element); 90 Suspension bushing (second embodiment, liquid-filled anti-vibration device); 92 socket body; 94 magnetic unit; 96 yoke (magnetic path forming part); 98 connecting arm (vibration-damping connecting target element, outer mounting element); 100 cylindrical mounting part.

Claims

[1] Liquid-filled anti-vibration device (10) comprising: an inner member (16), an outer cylindrical member (18) and a rubber-elastic main body (20), wherein the inner member (16) and the outer cylindrical member (18) are connected by the rubber-elastic main body (20); a plurality of fluid chambers (46) provided inside and filled with a magnetic functional fluid; a throttle channel (48) which allows the fluid chambers (46) to communicate with each other; and a magnetic unit (14) which applies a magnetic field to the magnetic functional fluid in the throttle channel (48) and is provided in an externally inserted state with respect to the outer cylindrical member (18), wherein the magnetic unit (14) comprises: a magnetic field generating part (50) that generates a magnetic field by being supplied with energy; and a magnetic path forming part (52) that induces a magnetic flux of the magnetic field generated by the magnetic field generating part (50), a magnetic gap part (68) provided in the magnetic path forming part (52) is arranged on an outer periphery of the throttle channel (48), and the magnetic field from the magnetic gap part (68) is applied to the magnetic functional fluid in the throttle channel (48), and on an outer peripheral surface of the outer cylindrical member (18), an installation part (70) on which an outer mounting member (72) realizing a connection between the outer cylindrical member (18) and a vibration-damping connection target member is installed is provided at a position axially offset from the magnetic field generating part (50), characterized by , that the outer mounting member (72) is an installation bracket connecting the outer cylindrical member (18) to the vibration-damping connection target member, and the installation bracket (72) attached to the outer cylindrical member (18) penetrates through the magnetic path forming part (52). [2] A liquid-filled anti-vibration device (10) according to claim 1, wherein the magnetic path forming part (52) comprises an inner circumferential magnetic path (64) extending along an inner peripheral side of the magnetic field generating part (50) in the axial direction, and an outer circumferential magnetic path (66) extending along an outer peripheral side of the magnetic field generating part (50) in the axial direction, the magnetic gap part (68) of the magnetic path forming part (52) is formed on the inner peripheral magnetic path (64) of the magnetic path forming part (52), and the installation bracket (72) passes through the outer peripheral magnetic path (66) of the magnetic path forming part (52) and projects toward an outer periphery. [3] A liquid-filled anti-vibration device (10) according to any one of claims 1 or 2, wherein a plurality of magnetic field generating parts (14) are arranged on two sides with respect to the fitting part (70) of the outer cylindrical member (18) in the axial direction. [4] A liquid-filled anti-vibration device (10) according to any one of claims 1 to 3, wherein the magnetic path forming part (52) is formed by two groove-like metal fittings (54) which are concavely shaped, open to an inner side in the axial direction and are opposed to each other, the magnetic field generating part (50) is arranged on an inner side of each of the groove-like metal fittings (54) and the magnetic gap part (68) is provided between the inner peripheral wall parts (58) of the two groove-like metal fittings (54).

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