Fluid-enclosed cylinder-type vibration isolator

Abstract

Provided is a fluid-enclosed cylinder-type vibration isolator of a novel structure, which can efficiently control the flow characteristics of a restriction passage, and which can easily adjust or switch the vibration isolation characteristics while suppressing power consumption. A fluid-enclosed cylinder-type vibration isolator 10 in which an inner shaft member 14 and an outer cylinder member 16 are elastically coupled by a main body rubber elastic body 18, and a plurality of fluid chambers 38a, 38b are provided to communicate with each other through a restriction passage 40, wherein the fluid enclosed in the fluid chambers 38a, 38b is a magnetic functional fluid, a magnetic unit 58 that generates a magnetic field by energization is provided, magnetic path forming members 44, 44 that are acted on by the magnetic field generated by the magnetic unit 58 are arranged on the side wall portions on both sides of the restriction passage 40, and a magnetic flux concentration portion 46 is provided in at least one of the magnetic path forming members 44, 44, and the dimension of the magnetic flux concentration portion 46 in the length direction of the restriction passage 40 decreases toward the inside of the opposing direction.

Description

Technical Field

[0001] This invention relates to a fluid-sealed cylindrical vibration damping device that utilizes the vibration damping effect based on the flow of fluid sealed inside. Background Technology

[0002] As a type of vibration damping device used in motor vehicle engine mounts and the like, cylindrical vibration damping devices with a structure that elastically connects the inner shaft member and the outer cylinder member using a main rubber elastomer have long been known. Furthermore, fluid-sealed cylindrical vibration damping devices that utilize the vibration damping effect based on the flow of fluid sealed inside have also been known for improving vibration damping performance. For example, Japanese Patent Application Publication No. 2008-151215 (Patent Document 1) and German Patent Application Publication No. 102011117749 (Patent Document 2) disclose the use of fluid flow through a throttling path to achieve excellent vibration damping performance.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2008-151215

[0006] Patent Document 2: German Patent Application Publication No. 102011117749 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] Incidentally, while the vibration damping effect based on the throttling path is effective for vibrations at a specific frequency pre-tuned in the throttling path, it is difficult to achieve the same effect for vibrations deviating from the tuning frequency. Therefore, to achieve effective vibration damping for a wider frequency range, for example, Patent Document 2 investigated switching the vibration damping characteristics by using a magnetorheological fluid (MRF) as the fluid encapsulated inside and controlling the strength of the magnetic field acting on the MRF. Specifically, as the magnetic field applied to the MRF increases, the viscosity of the MRF increases, the flow resistance of the throttling path increases, and the tuning frequency of the throttling path becomes a lower frequency. Therefore, by controlling the strength of the magnetic field acting on the MRF according to the frequency of the input vibration, a vibration damping effect based on the throttling path can be effectively obtained for vibration inputs in a wider frequency range.

[0009] In Patent Document 2, to achieve vibration damping performance across a wider frequency range, a stronger magnetic field is required to control the viscosity of the magnetorheological fluid over a larger area. However, generating a stronger magnetic field increases power consumption. Furthermore, recent motor vehicles, for example, have seen a significant increase in power consumption due to the proliferation of electrical components and rapid advancements in technology. There is a need to prevent further increases in power consumption, thus limiting the permissible power consumption of vibration damping devices.

[0010] The problem to be solved by the present invention is to provide a novel fluid-sealed cylindrical vibration damping device that can achieve efficient control of the flow characteristics of the throttling path, and for example, can easily achieve effective adjustment or switching of vibration damping characteristics while suppressing power consumption.

[0011] means for solving problems

[0012] Hereinafter, preferred embodiments for mastering the present invention will be described. However, the embodiments described below are exemplary and can be appropriately combined with each other. Furthermore, the various constituent elements described in each embodiment can be identified and used as independently as possible, or appropriately combined 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 cylindrical vibration damping device. The inner shaft component and the outer cylinder component of the fluid-sealed cylindrical vibration damping device are elastically connected by a main body rubber elastomer. Multiple fluid chambers containing fluid are configured to be interconnected through a throttling flow path. The fluid sealed in the fluid chambers is a magnetic functional fluid. The fluid-sealed cylindrical vibration damping device has a magnetic unit that generates a magnetic field by energizing it. Magnetic circuit forming members that are acted upon by the magnetic field generated by the magnetic unit are arranged on the sidewalls of the opposite sides of the throttling flow path. At least one of the magnetic circuit forming members arranged on the sidewalls of the opposite sides is provided with a magnetic flux concentrating part. The size of the magnetic flux concentrating part in the length direction of the throttling flow path decreases towards the inside in the opposite direction.

[0014] According to the fluid-sealed cylindrical vibration damping device with the structure conforming to this method, the magnetic flux is concentrated by the flux concentration section, which can exert the magnetic force generated by the magnetic unit on the magnetic functional fluid in the throttling path with high density. Therefore, the flow characteristics of the throttling path can be efficiently controlled with less current, and the required vibration damping performance can be easily obtained while suppressing power consumption.

[0015] The second method is based on the fluid-sealed cylindrical vibration damping device described in the first method. The magnetic circuit forming components disposed on the side wall portions on both sides of the throttling flow path are independent components, but are connected to each other by connecting parts.

[0016] According to the fluid-sealed cylindrical vibration damping device formed in accordance with this method, a pair of magnetic circuit forming components can be integrated, making the manufacture of the vibration damping device easier.

[0017] The third method is based on the fluid-sealed cylindrical vibration damping device described in the second method, wherein the magnetic circuit forming member disposed on the side wall portion on both sides of the throttling flow path is made of a strongly magnetic material, and the connecting part is made of a non-magnetic material.

[0018] According to the fluid-sealed cylindrical vibration damping device with the structure formed in accordance with this method, by making the connecting part that connects a pair of magnetic circuit forming members to each other a non-magnetic material, it is possible to suppress the situation where magnetic flux is guided to the connecting part between a pair of magnetic circuit forming members, and to enable magnetic force to act efficiently on the throttling path between a pair of magnetic circuit forming members.

[0019] The fourth method is based on the fluid-sealed cylindrical vibration damping device described in either the second or third method, wherein the magnetic circuit forming member disposed on the side wall portion on both sides of the throttling flow path is integrally formed with the connecting portion.

[0020] According to the fluid-sealed cylindrical vibration damping device formed in accordance with this method, for example, by integrally forming a connecting portion with respect to a pair of magnetic circuit forming members, the pair of magnetic circuit forming members can be easily connected using the connecting portion. It should be noted that, for example, by integrally forming a pair of magnetic circuit forming members with respect to the connecting portion, the pair of magnetic circuit forming members can also be easily connected using the connecting portion.

[0021] The fifth method, based on the fluid-sealed cylindrical vibration damping device described in the second or third method, involves the connecting part, which is composed of split components, being later fixed to the magnetic circuit forming member disposed on the side wall portion on both sides of the throttling flow path, thereby connecting the magnetic circuit forming member disposed on the side wall portion on both sides of the throttling flow path.

[0022] According to the fluid-sealed cylindrical vibration damping device formed in accordance with this method, since the pair of magnetic circuit forming members and the connecting part are separate components, these pair of magnetic circuit forming members and the connecting part can be easily manufactured separately.

[0023] The sixth method is based on the fluid-sealed cylindrical vibration damping device described in any of the first to fifth methods, wherein the sidewall portions on both sides of the throttling passage are formed as a combination structure of the magnetic circuit forming member and the sidewall member made of non-magnetic material, wherein the magnetic circuit forming member partially constitutes the sidewall portion of the throttling passage in the length direction.

[0024] According to the fluid-sealed cylindrical vibration damping device formed in accordance with this method, the magnetic flux concentration part can be reduced in the length direction of the throttling path to achieve magnetic flux concentration, and the path length of the throttling path required for vibration damping characteristics can be ensured by using sidewall members made of non-magnetic material.

[0025] The seventh method is based on the fluid-sealed cylindrical vibration damping device described in any of the first to sixth methods, wherein the magnetic circuit forming members disposed on the side wall portions on both sides of the throttling flow path are formed into a shape that is symmetrical to each other.

[0026] According to the fluid-sealed cylindrical vibration damping device with the structure in accordance with this method, magnetic flux concentration sections are respectively provided on the magnetic circuit forming members on both sides. The magnetic flux concentration sections on both sides are arranged opposite each other. Therefore, in the opposite arrangement of the magnetic flux concentration sections on both sides, the magnetic force acts efficiently on the magnetic functional fluid in the throttling flow path.

[0027] The eighth embodiment is based on the fluid-sealed cylindrical vibration damping device described in any of the first to seventh embodiments, wherein the magnetic flux concentration section in the magnetic circuit forming member has a tapered portion whose dimensions in the length direction of the throttling path gradually decrease towards the inside of the opposite direction.

[0028] According to the fluid-sealed cylindrical vibration damping device formed in accordance with this method, the size of the magnetic flux concentration part in the length direction of the throttling path can be reduced at the end of the side wall portion of the throttling path in the opposite direction, and the volume of the magnetic circuit forming member can be easily ensured.

[0029] The ninth embodiment, based on the fluid-sealed cylindrical vibration damping device described in any of the first to eighth embodiments, wherein the magnetic circuit forming member extends to a position further outward than the throttling passage on at least one side of the length direction of the throttling passage.

[0030] According to the fluid-sealed cylindrical vibration damping device with a structure in accordance with this method, by making the magnetic circuit forming member longer in the length direction of the throttling flow path, a wider range of magnetic flux can be guided to the magnetic flux concentration section, so that the magnetic force can be more concentrated and act on the magnetic functional fluid in the throttling flow path more efficiently.

[0031] The tenth method is based on the fluid-sealed cylindrical vibration damping device described in the ninth method, wherein the magnetic circuit forming member extends from both circumferential ends of the throttling flow path toward the circumferentially outward and is integrally formed into a ring extending circumferentially along the outer cylinder member.

[0032] According to the fluid-sealed cylindrical vibration damping device with the structure in accordance with this method, the magnetic circuit forming member extending in the length direction of the throttling passage to a position outside the throttling passage is integrally formed into a ring extending circumferentially along the outer cylinder member, thereby easily ensuring space to accommodate a longer magnetic circuit forming member in the cylindrical vibration damping device.

[0033] The eleventh method is based on the fluid-sealed cylindrical vibration damping device described in the tenth method. An intermediate sleeve is fixed to the outer periphery of the main rubber elastomer. The magnetic circuit forming member, which is formed as a ring, is installed in the intermediate sleeve in an outer sleeve state, and the outer cylinder member is installed in the magnetic circuit forming member in an outer sleeve state.

[0034] According to the fluid-sealed cylindrical vibration damping device formed in accordance with this method, since the magnetic circuit forming member is held between the intermediate sleeve and the outer cylinder member, the magnetic circuit forming member can be easily installed and can be configured in a stable support manner.

[0035] In the twelfth embodiment, based on the fluid-sealed cylindrical vibration damping device described in any of the first to eleventh embodiments, the front end face of the inner side of the magnetic flux concentration section of the magnetic circuit forming member has a dimension in the length direction of the throttling flow path that is less than 60% of the total length of the throttling flow path.

[0036] According to the fluid-sealed cylindrical vibration damping device formed in accordance with this method, in the length direction of the throttling path, the size of the front end face of the magnetic flux concentration section in the opposite direction is small enough relative to the total length of the throttling path, so that it can exert a concentrated magnetic force on the magnetically functional fluid in the throttling path.

[0037] Invention Effects

[0038] According to the present invention, in the fluid-sealed cylindrical vibration damping device, it is possible to achieve highly efficient control of the flow characteristics of the throttling path, and it is also easy to meet requirements such as suppressing power consumption and effectively adjusting or switching vibration damping characteristics. Attached Figure Description

[0039] Figure 1 This is a cross-sectional view showing the engine bracket as a first embodiment of the present invention, and is equivalent to... Figure 2 The diagram of section II.

[0040] Figure 2 yes Figure 1Sectional view II-II.

[0041] Figure 3 It constitutes Figure 1 A perspective view of the throttling component of the engine mount shown.

[0042] Figure 4 yes Figure 3 The front view of the throttling component shown.

[0043] Figure 5 yes Figure 4 The bottom view of the throttling component shown.

[0044] Figure 6 yes Figure 4 The side view of the throttling component shown.

[0045] Figure 7 It constitutes Figure 1 A three-dimensional view of the magnetic circuit forming component of the throttling component shown.

[0046] Figure 8 This is a cross-sectional view showing the engine bracket as a second embodiment of the present invention.

[0047] Figure 9 It constitutes Figure 8 A perspective view of the throttling component of the engine mount shown.

[0048] Figure 10 yes Figure 9 The front view of the throttling component shown.

[0049] Figure 11 This is a cross-sectional view showing the engine bracket as a third embodiment of the present invention, which is equivalent to... Figure 12 A diagram of the XI-XI cross section.

[0050] Figure 12 yes Figure 11 Sectional view XII-XII.

[0051] Figure 13 It constitutes Figure 11 The front view of the throttling component of the engine mount shown.

[0052] Figure 14 yes Figure 13 The bottom view of the throttling component shown.

[0053] Figure 15 yes Figure 13 The side view of the throttling component shown.

[0054] Figure 16 yes Figure 13 XVI-XVI sectional view.

[0055] Figure 17 This is a cross-sectional view showing the engine bracket as a fourth embodiment of the present invention.

[0056] Figure 18 This is represented by the state of the outer cylinder components not being assembled. Figure 17 The image shows a 3D view of the engine mount. Detailed Implementation

[0057] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0058] exist Figure 1 , Figure 2 In this paper, as a first embodiment of a vibration damping device forming a structure according to the present invention, an engine mount 10 for a motor vehicle is shown. The engine mount 10 is a fluid-sealed vibration damping device, comprising a vibration damping device body 12. The vibration damping device body 12 has a structure in which an inner shaft member 14 and an outer cylinder member 16 are connected by a body rubber elastomer 18. In the following description, in principle, axial direction refers to the direction of the central axis of the mount, i.e. Figure 1 The left and right directions and the up and down directions refer to the main vibration input directions, i.e. Figure 2 The up and down directions in the middle.

[0059] The inner shaft member 14 is formed in a generally cylindrical shape with a small diameter and extends linearly in the axial direction. The inner shaft member 14 is preferably made of a non-magnetic material, such as stainless steel or aluminum alloy. A stop member 20 is fixed at the axial central portion of the inner shaft member 14. The stop member 20 is integrally formed in a ring shape, such as... Figure 2 As shown, it has two fluid chambers 38, which will be described later, and two protrusions 22 protruding from both sides of the fluid chambers 38 in the vertical direction.

[0060] like Figure 1 , Figure 2 As shown, an intermediate sleeve 24 is disposed around the inner shaft member 14. The intermediate sleeve 24 is formed into a generally cylindrical shape with a diameter larger than that of the inner shaft member 14, and is disposed in an outer sleeve state that is separated from the inner shaft member 14 on the circumferential side. The intermediate sleeve 24 has windows 26 at two circumferential locations. The windows 26 extend radially through the intermediate sleeve 24 at its axial central portion. A groove 28 is provided between the two windows 26 of the intermediate sleeve 24 on the circumferential side. The groove 28 is a recessed portion in the intermediate sleeve 24 that is locally formed with a small diameter and is formed to open on the outer circumferential surface, and extends circumferentially at the axial central portion of the intermediate sleeve 24, with its two circumferential ends reaching one of the two windows 26. The intermediate sleeve 24 is preferably made of a non-magnetic material, such as stainless steel or aluminum alloy, in the same manner as the inner shaft member 14.

[0061] The inner shaft member 14 and the intermediate sleeve 24 are connected by a main rubber elastomer 18. The main rubber elastomer 18 is generally cylindrical, with its inner circumferential portion fixed to the inner shaft member 14 and its outer circumferential portion fixed to the intermediate sleeve 24. Furthermore, the main rubber elastomer 18 covers the inner surface of the groove 28 of the intermediate sleeve 24 and is also fixed to the outer circumferential surface of the intermediate sleeve 24 at the groove 28. The main rubber elastomer 18 can be formed as an integral vulcanized molded part comprising the inner shaft member 14 and the intermediate sleeve 24.

[0062] like Figure 2 As shown, the main body rubber elastomer 18 has two pouch-shaped portions 30. Each pouch-shaped portion 30 is formed as a recessed portion opening on the outer peripheral surface of the main body rubber elastomer 18, and in this embodiment, it opens on both sides in the vertical direction. The pouch-shaped portions 30 are positioned corresponding to the window portion 26 of the intermediate sleeve 24, and the peripheral edge of the opening of the pouch-shaped portion 30 is fixed to the window portion 26, allowing the pouch-shaped portion 30 to open outwards through the window portion 26. A protrusion 22 of a stop member 20 protrudes from the bottom inner periphery of the pouch-shaped portion 30.

[0063] An outer cylinder member 16 is fixedly attached to the intermediate sleeve 24, which is fixed to the main rubber elastomer 18. The outer cylinder member 16 is formed into a generally cylindrical shape with a diameter larger than that of the inner shaft member 14. One axial end of the outer cylinder member 16 has a flange-like portion 32 protruding towards the outer periphery. The outer cylinder member 16 is made of a non-magnetic material, such as stainless steel or aluminum alloy. The inner circumferential surface of the outer cylinder member 16 is covered by a sealing rubber layer 34.

[0064] The outer cylinder component 16 is assembled onto the intermediate sleeve 24 in an outer sleeve state, for example, by means of a diameter reduction process such as octagonal deep drawing, and is fitted onto the outer circumferential surface of the intermediate sleeve 24. In addition, the outer cylinder component 16 and the intermediate sleeve 24 are fluid-tightly sealed by sandwiching a sealing rubber layer 34.

[0065] The window 26 of the intermediate sleeve 24 is fluid-tightly covered by the outer cylinder member 16. Thus, two fluid chambers 38 are formed between the inner shaft member 14 and the outer cylinder member 16: a first fluid chamber 38a and a second fluid chamber 38b. The walls on both axial sides of each fluid chamber 38a and fluid chamber 38b are made of a main body rubber elastomer 18. Furthermore, in each fluid chamber 38a and fluid chamber 38b, the protrusion 22 of the stop member 20 protrudes radially from the inner side to the outer side. The first fluid chamber 38a and the second fluid chamber 38b are arranged to be circumferentially separated from each other. In this embodiment, the first fluid chamber 38a and the second fluid chamber 38b are arranged on both sides in the vertical direction relative to the inner shaft member 14, that is, on both sides in the direction perpendicular to the axis relative to the central axis of the support.

[0066] Each fluid chamber 38a and fluid chamber 38b contains a magnetic functional fluid. The magnetic functional fluid is a fluid whose viscosity increases due to the action of a magnetic field. The magnetic functional fluid can be any of a magnetorheological fluid (MRF), a magnetic fluid (MF), or a magnetic composite fluid (MCF) formed by mixing a magnetorheological fluid and a magnetic fluid. Preferably, the magnetic functional fluid is a magnetorheological fluid whose viscosity changes significantly with respect to the magnetic field; however, a magnetic composite fluid in which the increase in viscosity can be easily adjusted by the mixing ratio of the magnetorheological fluid and the magnetic fluid is also preferred.

[0067] Magnetic functional fluids are, for example, suspensions or colloidal solutions in a base liquid such as water or oil in which strongly magnetic particles are dispersed. In order to prevent the strongly magnetic particles from agglomerating or settling in the base liquid, it is preferable to use a surfactant to cover the surface of the strongly magnetic particles or to disperse the strongly magnetic particles in a base liquid in which a surfactant has been added.

[0068] The strongly magnetic particles are, for example, metallic particles such as iron, ferrite, or magnetite, preferably with a particle size of approximately 8 nm to 10 μm. The substrate is not particularly limited as long as it can disperse the strongly magnetic particles; for example, water, isoparaffins, alkylnaphthalenes, perfluoropolyethers, polyolefins, and silicone oils can be used. Furthermore, the substrate is preferably an incompressible fluid. The surfactant is selected appropriately depending on the substrate; for example, oleic acid is preferred. It should be noted that the main difference between magnetorheological fluids and magnetic fluids lies in the particle size of the strongly magnetic particles; the particle size of the strongly magnetic particles in magnetorheological fluids is larger than that in magnetic fluids.

[0069] The first fluid chamber 38a and the second fluid chamber 38b are interconnected via a throttling passage 40. The throttling passage 40 extends circumferentially between the outer cylinder member 16 and the intermediate sleeve 24, with both ends connected to one of the first fluid chamber 38a and the second fluid chamber 38b. The area forming the throttling passage 40 is formed by fluid-tightly blocking the outer peripheral opening of the groove 28 provided in the intermediate sleeve 24 using the outer cylinder member 16. In this embodiment, a pair of throttling passages 40 are provided on both circumferential sides of the first fluid chamber 38a, connecting the first fluid chamber 38a and the second fluid chamber 38b circumferentially. The pair of throttling passages 40 are located in a direction perpendicular to the central axis of the support, perpendicular to the opposing direction of the first fluid chamber 38a and the second fluid chamber 38b. Figure 2The first fluid chamber 38a and the second fluid chamber 38b are connected side-by-side on both sides of the engine mount 10 in the radial direction (left and right). The first fluid chamber 38a and the second fluid chamber 38b, along with the throttling passages 40, are arranged circumferentially for efficient space utilization, thus suppressing the enlargement of the engine mount 10. Furthermore, in this embodiment, the pair of throttling passages 40 are formed to have equal cross-sectional areas and lengths, but the cross-sectional areas and / or lengths of the two throttling passages may also be different from each other.

[0070] Additionally, the sidewall portion of the throttling passage 40 is formed by the throttling member 42. For example... Figures 3-6 As shown, the throttling member 42 is integrally formed in the shape of a curved plate. The throttling member 42 has the following features: Figure 7 The pair of magnetic circuit forming components 44 are shown.

[0071] The magnetic circuit forming member 44 is formed of strongly magnetic materials such as iron, nickel, chromium, and soft magnetic ferrite. The throttling member 42 has axial ( Figure 4 The magnetic circuit forming members 44 are a pair of independent magnetic circuit forming members 44 that are spaced apart by a predetermined distance in the vertical direction. In this embodiment, the pair of magnetic circuit forming members 44 are rotationally symmetrical with a 180-degree angle, achieving commonality between them. Each pair of magnetic circuit forming members 44 includes a flux concentrating portion 46. The circumferential length of the flux concentrating portion 46 is smaller at its inner end in the opposing direction than at its outer end, and the circumferential length decreases towards the inner side of the opposing direction. The entire flux concentrating portion 46 is composed of a tapered portion 48 whose circumferential length gradually decreases towards the inner side of the opposing direction. In this embodiment, the two ends of the tapered portion 48 in the circumferential direction are inclined inward at approximately the same angle toward the opposing inner side of the pair of magnetic circuit forming members 44. The central portion of the magnetic circuit forming member 44 in the circumferential direction is formed to be thicker in the radial direction than the outer portion of the circumferential direction located on the outer side of the opposing inner end of the flux concentration portion 46, and the circumferential length of this central portion is the same as that of the inner end of the opposing inner end of the flux concentration portion 46. The outer circumferential surface of the magnetic circuit forming member 44 is formed as a smooth curved surface on a generally single cylindrical surface, and the central portion in the circumferential direction protrudes inward from the outer portion in the circumferential direction to form a thick wall. The magnetic circuit forming member 44 is preferably a soft magnetic material with low remanent magnetization.

[0072] Sidewall members 50 are fixedly attached to a pair of magnetic circuit forming members 44, and these sidewall members 50 are connected to each other through connecting portions 52 integrally formed at both ends in the circumferential direction. Thus, the pair of magnetic circuit forming members 44, which are independent components, are connected via sidewall members 50 and connecting portions 52 to form a throttling member 42.

[0073] The sidewall member 50 is made of a non-magnetic material, such as synthetic resin, rubber, aluminum alloy, or stainless steel. The sidewall member 50 is fixed to the axial outer surface and circumferential end faces of the magnetic circuit forming member 44. The circumferential end faces of the sidewall member 50 are formed as planes extending approximately parallel to the circumferentially orthogonal plane relative to the circumferential center of the magnetic circuit forming member 44, and the circumferential end faces of the sidewall member 50 are approximately parallel to each other. The sidewall members 50 are also located on the two outer sides of the circumference relative to the flux concentration portion 46 (conical portion 48), and are fixed to a pair of magnetic circuit forming members 44. The sidewall members 50 are axially spaced at a predetermined distance from each other in a position closer to the outer sides of the circumferential flux concentration portion 46. The distance between the opposing sides of the pair of flux concentration portions 46 is approximately the same as the distance between the opposing sides of the pair of sidewall members 50.

[0074] The connecting portion 52 protrudes inward at the circumferential ends of the sidewall members 50 and is axially continuous across the pair of sidewall members 50, thereby connecting the pair of sidewall members 50 integrally. Furthermore, the pair of magnetic circuit forming members 44 are interconnected via the pair of sidewall members 50 through the connecting portion 52, thereby forming a throttling member 42 comprising the pair of magnetic circuit forming members 44 and the pair of sidewall members 50. In this embodiment, the connecting portion 52 is integrally formed with the sidewall members 50. The connecting portion 52 is made of a non-magnetic material, such as synthetic resin, rubber, aluminum alloy, or stainless steel. Connecting portions 52 are respectively provided at the two circumferential ends of the sidewall member 50, and the two circumferential ends of the sidewall member 50 are connected, thereby improving the shape stability of the throttling member 42, etc. The connecting portions 52 are located on the outer side of the magnetic circuit forming member 44 in the circumferential direction.

[0075] A pair of magnetic circuit forming members 44 and a pair of sidewall members 50 are integrally connected and positioned to each other via a connecting portion 52, thereby forming a circumferentially extending slit-like portion 54 between the axially opposing surfaces of the pair of magnetic circuit forming members 44 and the pair of sidewall members 50 in the throttling member 42. The slit-like portion 54 extends radially through the thickness direction of the throttling member 42 and opens on both the outer and inner circumferential surfaces of the throttling member 42. The sidewall portion of the slit-like portion 54 is a combination structure of a magnetic circuit forming member 44 made of a strongly magnetic material and a sidewall member 50 made of a non-magnetic material. More specifically, the central circumferential portion of the sidewall portion of the slit-like portion 54 is formed by the magnetic circuit forming member 44, and the two circumferentially opposite portions are formed by the sidewall members 50.

[0076] The throttling member 42 with such a structure has a magnetic circuit forming member 44, a sidewall member 50, and a connecting portion 52 integrally formed. That is, in this embodiment, the throttling member 42 is integrally formed by inserting the magnetic circuit forming member 44 into the sidewall member 50, the sidewall member 50, and the connecting portion 52.

[0077] like Figure 1 , Figure 2 As shown, the throttling member 42 is inserted into the groove 28 and installed in the intermediate sleeve 24. That is, the throttling member 42 is positioned radially by overlapping with the outer peripheral surface of the intermediate sleeve 24, and is positioned circumferentially relative to the intermediate sleeve 24 by overlapping the connecting portion 52 protruding towards the inner periphery with the circumferential end faces of the connecting portion 52 and the bottom wall portion of the groove 28. Moreover, the outer sleeve member 16 is fitted onto the intermediate sleeve 24 in an outer sleeve state, thereby overlapping the outer peripheral surface of the throttling member 42 with the inner peripheral surface of the outer sleeve member 16 through the sealing rubber layer 34, thereby positioning the throttling member 42 between the intermediate sleeve 24 and the outer sleeve member 16.

[0078] By overlapping the inner circumferential surface of the throttling member 42 with the bottom wall of the groove 28 of the intermediate sleeve 24, the inner circumferential opening of the slit 54 of the throttling member 42 is covered by the intermediate sleeve 24. The inner surface of the groove 28 is covered by the rubber layer 56, thereby pressing the throttling member 42 against the bottom wall of the groove 28 through the rubber layer 56, and the inner circumferential opening of the slit 54 is liquid-tightly sealed.

[0079] In addition, the outer peripheral surface of the throttling member 42 overlaps with the inner peripheral surface of the outer cylinder member 16 through the sealing rubber layer 34, thereby sealing the outer peripheral opening of the slit-like portion 54 of the throttling member 42 in a liquid-tight manner.

[0080] Thus, a tunnel-shaped flow path extending circumferentially is formed between the intermediate sleeve 24 and the outer cylinder member 16 using a slit-like portion 54. Furthermore, both circumferential ends of the tunnel-shaped flow path communicate with one of the first fluid chamber 38a and the second fluid chamber 38b, thereby forming a throttling flow path 40 that connects the first fluid chamber 38a and the second fluid chamber 38b. The throttling flow path 40 extends circumferentially along the outer cylinder member 16, and its length direction is set along the circumferential direction of the outer cylinder member 16. In this embodiment, throttling members 42 are installed on a pair of groove-shaped portions 28 provided on both radial sides of the intermediate sleeve 24, and throttling flow paths 40 are formed on these throttling members 42. Furthermore, the pair of throttling flow paths 40 can be tuned to the same frequency or different frequencies. In short, the pair of throttling flow paths 40 do not need to have the same cross-sectional area, length, or shape.

[0081] The sidewall portions on both sides of the throttling passage 40 are formed by the sidewall portions of the slit-shaped portion 54 in the throttling member 42. Therefore, regarding the sidewall portions of the throttling passage 40, the central portion in the passage length direction of the throttling passage 40 is partially formed by the flux concentration portion 46 of the magnetic circuit forming member 44, and both sides in the passage length direction relative to the magnetic circuit forming member 44 are formed by sidewall members 50. The sidewall portions of the throttling passage 40 are a combination structure of the magnetic circuit forming member 44 made of a strongly magnetic material and the sidewall members 50 made of a non-magnetic material. Even if the length dimension in the passage length direction of the inner axial end of the flux concentration portion 46 becomes smaller, the passage length of the throttling passage 40 can be set with a large degree of freedom using the sidewall members 50 arranged on both sides in the passage length direction relative to the flux concentration portion 46.

[0082] The front end face of the flux concentration section 46, which forms the inner surface of the sidewall of the throttling path 40, preferably has a dimension in the passage length direction of the throttling path 40 that is 60% or less of the total length of the throttling path 40 (the overall passage length dimension of the throttling path 40). More preferably, the dimension of the front end face of the flux concentration section 46 in the passage length direction of the throttling path 40 is 40% or less of the total length of the throttling path 40. The front end face of the flux concentration section 46 in the axially inner direction can be a sharp shape with a dimension approximately 0 in the passage length direction of the throttling path 40, but it is preferable to extend in the passage length direction by a certain degree, for example, 10% or more of the total length of the throttling path 40.

[0083] A magnetic unit 58 is installed on the outer cylinder component 16. The magnetic unit 58 is formed in a circular ring shape and has a structure in which a magnetic yoke component 62 is installed around the coil 60. Moreover, the magnetic unit 58 generates a magnetic field by energizing the coil 60.

[0084] The coil 60 is integrally formed in a cylindrical or ring shape, and is structured with an electric wire made of a conductive material wound around it. The coil 60 is formed by winding it onto a spool made of synthetic resin. The coil 60 is preferably made of a material with excellent conductivity, preferably, for example, copper or aluminum alloy. It should be noted that the coil 60 is electrically connected to the terminals of the connector 66, and is electrically connected to an external power control device (not shown) via the connector 66.

[0085] The yoke member 62 is formed of a strongly magnetic material such as iron. The yoke member 62 has a U-shaped cross-section that opens towards the inner periphery and is configured to cover both axial end faces and the outer peripheral surface of the coil 60. Therefore, when a circumferential current flows through the coil 60, the magnetic flux of the coil 60 is guided to the yoke member 62, which is a strongly magnetic body; that is, a magnetic circuit is formed through the yoke member 62, reducing leakage of magnetic flux to the axial outer side and the outer periphery. In this embodiment, the yoke member 62 is formed as a segmented structure so that it can be assembled to the coil 60.

[0086] like Figure 1 , Figure 2 As shown, the magnetic unit 58 is sleeved on the outer cylinder member 16 and assembled on the outer circumferential side of the outer cylinder member 16 with its inner circumferential surface overlapping the outer circumferential surface of the outer cylinder member 16. A cylindrical cover member 70 is disposed on the outer circumference of the magnetic unit 58, and the magnetic unit 58 is disposed between the outer cylinder member 16 and the cylindrical cover member 70.

[0087] The cylindrical cover member 70 is generally cylindrical in shape and is made of non-magnetic materials such as stainless steel or aluminum alloy. Both axial ends of the cylindrical cover member 70 protrude inwards. When fitted over the outer cylindrical member 16, one axial end overlaps axially with the flange-like portion 32 of the outer cylindrical member 16, thereby positioning the cylindrical cover member 70 axially relative to the outer cylindrical member 16. Furthermore, the magnetic unit 58 is sandwiched between the flange-like portion 32 of the outer cylindrical member 16 and the other axial end of the cylindrical cover member 70, separated by a cushioning material such as rubber, thereby positioning it axially relative to the outer cylindrical member 16. In summary, the magnetic unit 58 is radially positioned by being sandwiched between the outer cylindrical member 16 and the cylindrical cover member 70, and axially positioned by being sandwiched between the flange-like portion 32 of the outer cylindrical member 16 and the other axial end of the cylindrical cover member 70, thus being fixedly installed relative to the outer cylindrical member 16.

[0088] The engine mount 10 is mounted, for example, to the power unit 72, which serves as a vibration-damping connection to the inner shaft member 14. The cylindrical cover member 70, fixed to the outer cylinder member 16, is mounted to the vehicle body 74, which serves as the vibration-damping connection to the other side, thus mounting the vehicle. The cylindrical cover member 70 is fixed to the vehicle body 74, for example, by pressing it into mounting holes in the vehicle body 74. It should be noted that the inner shaft member 14 can also be mounted to the power unit 72 via an inner bracket (not shown). Similarly, the cylindrical cover member 70 can also be mounted to the vehicle body 74 via an outer bracket (not shown).

[0089] When the engine mount 10 is installed in the vehicle, when vertical vibrations in the first fluid chamber 38a and the second fluid chamber 38b are input to the engine mount 10, a flow of sealed fluid through the throttling passage 40 is generated between the first fluid chamber 38a and the second fluid chamber 38b, thereby exerting a vibration damping effect based on the fluid flow.

[0090] The engine mount 10 can control the magnetic field acting on the magnetic functional fluid flowing through the throttling passage 40 via the magnetic unit 58, thereby adjusting or switching the vibration damping characteristics by controlling the viscosity of the magnetic functional fluid. This control of the viscosity of the magnetic functional fluid by the magnetic unit 58 is achieved by energizing the opposing coil 60.

[0091] That is, the magnetic field formed around the coil 60 by energizing the coil 60 forms magnetic poles at the inner peripheral end of the yoke member 62 disposed around the coil 60. Furthermore, the magnetic flux between the magnetic poles of the yoke member 62 is guided to the magnetic circuit forming member 44, which is a strongly magnetic body. The magnetic circuit forming members 44 are axially opposed to each other, and a throttling passage 40 is formed between them, so the magnetic flux of the magnetic field acting on the magnetic circuit forming members 44 passes through the throttling passage 40. In other words, the sidewall portion of the throttling passage 40 is configured to include the magnetic circuit forming member 44, thereby guiding the magnetic flux of the magnetic field generated by the magnetic unit 58 to the throttling passage 40. Therefore, the magnetic field formed by energizing the coil 60 acts on the magnetically functional fluid within the throttling passage 40.

[0092] The viscosity of a magnetically functional fluid increases with the strength (magnetic flux density) of the applied magnetic field. Therefore, the viscosity of the magnetically functional fluid can be controlled by controlling the intensity of the current flowing through the coil 60. The upper limit of the intensity of the magnetic field acting on the magnetically functional fluid can be adjusted by the number of turns of the coil 60, its material, and the maximum value of the current flowing through the coil 60.

[0093] In this embodiment, magnetic circuit forming members 44 are disposed on the sidewall portions on both sides of the axially extending throttling passage 40. These magnetic circuit forming members 44 are arranged close to each other, so magnetic flux can easily pass through the magnetically functional fluid in the throttling passage 40 extending between the opposing surfaces of these magnetic circuit forming members 44. Therefore, magnetic force can be effectively applied to the magnetically functional fluid in the throttling passage 40, and the viscosity of the magnetically functional fluid can be effectively controlled by the magnetic unit 58 disposed on the outer periphery of the vibration damping device body 12.

[0094] The magnetic circuit forming members 44, which constitute the two side wall portions of the throttling flow path 40, each have a magnetic flux concentration section 46. This magnetic flux concentration section 46 gradually narrows in width along the length of the throttling flow path 40, facing inward in the opposite direction (i.e., towards the throttling flow path 40). The cross-sectional area of ​​the magnetic circuit in the magnetic flux concentration section 46 gradually decreases towards the throttling flow path 40, thus concentrating the magnetic flux on the throttling flow path 40 side, i.e., at the axial inner end, resulting in a higher magnetic flux density. In other words, the magnetic flux passage area in the throttling flow path 40 is limited to the central portion along the length of the throttling flow path 40, enabling a high-density magnetic flux to be locally applied to the magnetically functional fluid within the throttling flow path 40. By allowing a high-density magnetic flux to pass through the magnetically functional fluid within the throttling flow path 40, the viscosity of the magnetically functional fluid can be locally and efficiently increased within the throttling flow path 40. As a result, the flow resistance of the throttling path 40 can be significantly increased, and the resonant frequency of the fluid flow through the throttling path 40, i.e. the tuning frequency of the throttling path 40, can be adjusted with a large degree of freedom.

[0095] In this way, the magnetic flux acting on the circumferential whole relative to the axial outer end of the magnetic circuit forming member 44 converges towards the axial inner end at the magnetic flux concentration section 46, and acts concentratedly on the magnetic functional fluid within the throttling flow path 40 with increased magnetic flux density. Therefore, even if the magnetic field generated by the magnetic unit 58 is relatively weak, sufficient magnetic flux density can be used to exert magnetic force on the magnetic functional fluid within the throttling flow path 40. As a result, the current energized to the coil 60 of the magnetic unit 58 can be reduced to suppress power consumption, and excellent vibration damping performance can be obtained by controlling the viscosity of the magnetic functional fluid.

[0096] In this embodiment, the dimension of the throttling path 40 along the length of the front end face of the throttling path 40 of the flux concentrator 46 (i.e., the axially inner front end face) is 60% or less of the total length of the throttling path 40. This allows for a locally strong magnetic force to act on the throttling path 40 along its length, enabling efficient adjustment and switching of the desired vibration damping characteristics. Furthermore, by setting the length of the front end face of the flux concentrator 46 along the length of the throttling path 40 to at least 10% of the total length, the region of action of the magnetic flux on the magnetically functional fluid within the throttling path 40 is ensured, allowing for effective adjustment or switching of the vibration damping characteristics.

[0097] In this embodiment, the flux concentrator 46 is formed as a conical portion 48, and its length dimension continuously decreases towards the front end face of the throttling path 40. Therefore, compared to a stepped flux concentrator where the length dimension changes progressively, the length dimension of the front end face of the flux concentrator 46 can be reduced to the same extent, and the magnetic circuit cross-sectional area of ​​the flux concentrator 46 can be maximized in the conical portion 48. By maximizing the magnetic circuit cross-sectional area, the magnetic reluctance in the flux concentrator 46 can be reduced.

[0098] The magnetic circuit forming member 44 is preferably a soft magnetic material with low holding force. As a result, the magnetization of the magnetic circuit forming member 44 follows the control of the energization of the coil 60 with high precision, and the characteristics of the set throttling path 40 can be quickly changed according to the input vibration.

[0099] The throttling flow path 40 is formed between the intermediate sleeve 24 and the outer cylinder member 16, both of which are made of non-magnetic materials. Therefore, the outer cylinder member 16 and the intermediate sleeve 24 do not form a magnetic circuit, allowing magnetic flux to be concentrated in the magnetic circuit forming member 44. Thus, the magnetic field can be effectively applied to the magnetically functional fluid within the throttling flow path 40, thereby controlling the viscosity of the magnetically functional fluid.

[0100] It should be noted that there is no particular limitation on the specific method of adjusting or switching the performance (vibration damping characteristics) of the engine mount 10 by controlling the viscosity of the magnetic functional fluid flowing in the throttling path 40. As long as the control is performed in a way that meets the required performance, it is acceptable. The following is an example of one control method.

[0101] First, during the input of mid-frequency or high-frequency vibrations at idle speed or under normal driving conditions, no energizer is supplied to the coil 60, and the viscosity of the magnetic functional fluid within the throttling passage 40 decreases. Consequently, the flow resistance of the magnetic functional fluid in the throttling passage 40 decreases, and the low-viscosity magnetic functional fluid flows actively through the throttling passage 40. As a result, the spring characteristics of the engine mount 10 become softer, achieving good ride comfort through vibration insulation effects resulting from the reduced spring tension.

[0102] When a low-frequency, high-amplitude vibration, comparable to engine vibration, is input, the viscosity of the magnetic functional fluid within the throttling flow path 40 is increased by energizing the coil 60. Consequently, the flow resistance of the magnetic functional fluid within the throttling flow path 40 increases, and resonance phenomena related to the flow of the magnetic functional fluid in the throttling flow path 40 manifest at even lower frequencies. Therefore, the increased viscosity of the magnetic functional fluid flowing within the throttling flow path 40 effectively attenuates low-frequency vibrations, achieving a vibration damping effect through the attenuation of vibration energy.

[0103] Furthermore, when the power unit 72 tilts significantly due to sudden vehicle start-up, the coil 60 is energized to increase the viscosity of the magnetically functional fluid in the throttling circuit 40, thereby stiffening the spring characteristics of the engine mount 10. This suppresses the swaying of the power unit 72, improving vehicle handling stability and ride comfort.

[0104] In this way, the energization of the engine mount 10 to the coil 60 is controlled according to the input vibration, thereby appropriately switching between the soft spring characteristics with excellent vibration insulation and the hard spring characteristics with excellent vibration damping performance and support stability of the power unit 72, thus achieving excellent vibration damping performance. In this embodiment, the switching of energizing the coil 60 on / off is shown as an example, but not only can the energization of the coil 60 be controlled, but the characteristics of the engine mount 10 can also be adjusted by controlling the intensity of the current flowing through the coil 60. Specifically, for example, in the above-described characteristic control example, current flows in the coil 60 when there is engine vibration input and when the power unit 72 is tilted, but the intensity of the current flowing in the coil 60 can also be different from each other. That is, for example, a stronger current can flow when the power unit 72 is tilted than when there is engine vibration input, thereby more effectively suppressing the tilt displacement of the power unit 72. Furthermore, the aforementioned idling vibration, engine shaking, and lateral displacement of the power unit 72 are merely examples. By controlling the intensity of the current flowing in the coil 60 in more stages or continuously according to more types of input vibrations with different amplitudes and frequencies, it is also possible to adjust the characteristics of the engine mount 10 in more stages or continuously, thereby achieving excellent vibration damping performance. It should be noted that the energization of the coil 60 can also be controlled in such a way that the flow of the magnetic functional fluid in the throttling circuit 40 is completely blocked, and the throttling circuit 40 is essentially cut off.

[0105] exist Figure 8 In this paper, as a second embodiment of a fluid-sealed cylindrical vibration damping device with a structure according to the present invention, an engine mount 80 for a motor vehicle is shown. The engine mount 80 includes... Figure 9 , Figure 10 The throttling member 82 is shown. In the following description, components and parts that are substantially the same as those in other embodiments are labeled with the same reference numerals in the figures, and thus the description is omitted.

[0106] The throttling member 82 has the following structure: a pair of flow path members 88, consisting of a magnetic circuit forming member 44 and a sidewall member 86, are connected to each other at their two circumferential ends by a connecting member 90. The flow path member 88 has a structure in which sidewall members 86, made of non-magnetic material, are fixed to the axial outer surface and the two circumferential outer surfaces of the magnetic circuit forming member 44, which is made of a strongly magnetic material. The sidewall members 86 are generally long plate-shaped or rod-shaped and extend in a curved manner in the circumferential direction.

[0107] The connecting member 90 is plate-shaped and made of a non-magnetic material. The connecting member 90 includes a fixing portion 92 that overlaps with the circumferential end faces of the flow path member 88, and a connecting portion 94 that connects these fixing portions 92. The fixing portion 92 is shaped to approximately correspond to the circumferential end face of the flow path member 88. A threaded hole for inserting a screw 96 is formed through the fixing portion 92. The fixing portions 92 are fixed to each flow path member 88 and each side wall member 86 of the flow path member 88 by a plurality of screws 96, thereby fixing the connecting member 90 to the flow path member 88. Therefore, in this embodiment, the connecting members 90, each having a connecting portion 94, are subsequently fixed together by threaded fastening after forming, thereby connecting a pair of magnetic circuit forming members 44. It should be noted that the method of fixing the connecting component 90 to the flow path component 88 is not limited to thread fastening. For example, it can also be fixed by bonding, welding, mechanical locking, etc.

[0108] The fixing parts 92 are connected to each other by the connecting parts 94 at a position closer to the inner periphery of the side wall members 86. The fixing parts 92, connected by the connecting parts 94, are fixed to the circumferential end faces of the side wall members 86, thereby connecting a pair of flow path members 88 to each other via the connecting member 90 to form a throttling member 82. In this embodiment, the connecting part 94 is integrally formed with the fixing parts 92. The connecting member 90 may also be provided only at one circumferential end of the flow path members 88, but in this embodiment, the connecting member 90 is provided at both circumferential ends of the flow path members 88, thereby improving the shape stability of the throttling member 82.

[0109] The connecting portion 94 is configured to protrude inward from the side wall member 86, thereby forming a groove-shaped gap 98 that extends circumferentially between the fixing portion 92 and the fixing portion 92. Furthermore, the slit-like portion 54 formed between the pair of flow path members 88 and the flow path members 88 opens to both sides circumferentially through the connecting structural members 90 and the gap 98 provided at both ends of the circumferential direction.

[0110] The throttling member 82, which has such a structure, is installed in the groove-shaped portion 28 of the intermediate sleeve 24 in the same way as the throttling member 42 in the first embodiment. The end of the connecting member 90 of the flow path member 88 and the flow path member 88 protruding inwards overlaps with the circumferential end face of the groove-shaped portion 28, thereby positioning the throttling member 82 in the circumferential direction relative to the intermediate sleeve 24.

[0111] The inner peripheral opening of the slit-shaped portion 54 is closed by the intermediate sleeve 24, and the outer peripheral opening of the slit-shaped portion 54 is closed by the outer cylinder member 16, thereby forming a throttling passage 40. The slit-shaped portion 54 is connected to the first fluid chamber 38a and the second fluid chamber 38b through the connecting member 90, the gap 98 of the connecting member 90, and the gap 98.

[0112] The engine bracket 80, which has a throttling member 82 configured according to this embodiment, can achieve the same effect as the first embodiment. Furthermore, compared to the throttling member 42 of the first embodiment, where a pair of magnetic circuit forming members 44 are integrally connected via connecting portions 52 integrally formed with sidewall members 50 and sidewall members 50, the pair of magnetic circuit forming members 44 are configured as flow path members 88 with independent sidewall members 86 and sidewall members 86, and the pair of flow path members 88 are interconnected via separate connecting members 90, thereby forming the throttling member 82. Therefore, the sidewall member 86 and the connecting member 90 can be formed from different materials. For example, the sidewall member 86, which is difficult to require load resistance, can be made of a resin material with excellent formability. The connecting member 90, which may be affected by damage caused by input to the small cross-sectional area of ​​the connecting part 94, can be made of a synthetic resin material with higher strength, a non-magnetic metal material, etc. It is possible to select a combination of materials that correspond to the required performance.

[0113] exist Figure 11 , Figure 12 In this paper, as a third embodiment of a fluid-sealed cylindrical vibration damping device with a structure according to the present invention, an engine mount 100 for a motor vehicle is shown.

[0114] The engine mount 100 includes a throttling component 102. For example... Figures 13-16 As shown, the throttling member 102 includes a pair of magnetic circuit forming members 104 and a connecting portion 106 that connects the magnetic circuit forming members 104 to each other.

[0115] The magnetic circuit forming member 104 is formed of a strongly magnetic material and is shaped as a curved plate extending circumferentially. The magnetic circuit forming member 104 extends approximately half a circumference in the circumferential direction. A magnetic flux concentrating portion 108 protruding axially inward is integrally formed at one end of the magnetic circuit forming member 104 in the circumferential direction. The circumferential length of the magnetic flux concentrating portion 108 decreases towards the protruding end, and the cross-sectional area of ​​the section orthogonal to the protruding direction (the section perpendicular to the axis) also decreases towards the protruding end. The end face of the magnetic flux concentrating portion 108 on the other circumferential side is formed as a conical surface inclined circumferentially towards the axial inward direction, and the magnetic flux concentrating portion 108 is formed as a conical portion 48 tapering towards the axial inward direction at its front end.

[0116] In the throttling member 102, a pair of magnetic circuit forming members 104, which are approximately symmetrical in shape in the axial direction, are arranged opposite each other in the axial direction. The distance between the opposing surfaces of the pair of magnetic circuit forming members 104 is smaller in the opposing portion of the magnetic flux concentration section 108 than in other portions.

[0117] like Figure 13 , Figure 16 As shown, a pair of magnetic circuit forming members 104 are connected to each other at their opposite circumferential ends via a connecting portion 106, thereby forming a throttling member 102. The connecting portion 106 is made of a non-magnetic material, such as synthetic resin, and is disposed between the opposing surfaces of the pair of magnetic circuit forming members 104, and fixed to the opposing inner surfaces of the pair of magnetic circuit forming members 104. In this embodiment, the connecting portion 106 extends to a position on the outer side of the pair of magnetic circuit forming members 104 on the opposite circumferential side, and is fixed to the end face of the pair of magnetic circuit forming members 104 on the opposite circumferential side. It should be noted that the connecting portion 106 can be fixed to the pair of magnetic circuit forming members 104 after molding by means of bonding, welding, etc., or it can be integrally fixed during molding.

[0118] like Figure 11 , Figure 12 As shown, the throttling members 102 with this structure are arranged in a pair facing each other, with their circumferential ends abutting each other to form a ring. Each pair of throttling members 102 has a flux concentration section 108, and the circumferential ends of the flux concentration section 108 abutting each other circumferentially. Furthermore, each pair of throttling members 102 has a connecting section 106, and the circumferential ends of the connecting section 106 abutting each other circumferentially. The pair of throttling members 102 abutting each other circumferentially on the flux concentration section 108 side, thereby forming a continuous C-shaped ring on one axial side of the magnetic circuit forming member 104, and also forming a continuous C-shaped ring on the other axial side. In summary, a magnetic flux concentration section 108 is provided in the circumferential central portion of a magnetic circuit forming member 104 that is formed as a C-shaped ring extending in the circumferential direction. The pair of magnetic circuit forming members 104 are arranged opposite each other in the axial direction and are connected to each other at both ends in the circumferential direction by a connecting section 106.

[0119] A pair of throttling members 102 configured in a ring shape are mounted in an outer sleeve state on the intermediate sleeve 24. The two circumferential ends of each throttling member 102 are positioned axially relative to the intermediate sleeve 24 by being inserted into a groove 28 of the intermediate sleeve 24, one of the grooves 28. Furthermore, by assembling an outer sleeve member 16 on the intermediate sleeve 24, the outer sleeve member 16 is mounted in an outer sleeve state on the pair of throttling members 102, and the throttling members 102 are held between the intermediate sleeve 24 and the outer sleeve member 16.

[0120] The throttling member 102 is configured to circumferentially cross the window portion 26 of the intermediate sleeve 24 of the vibration damping device body 12. Two throttling members 102 are configured to extend circumferentially at the opening portions of each window portion 26. The throttling members 102 can also be independent components with different structures, but in this embodiment they are common components, installed on the vibration damping device body 12 with different orientations.

[0121] The slit-shaped portion 54 formed between the flux concentration portion 108 and the opposing surface of the flux concentration portion 108 in each throttling member 102, with its inner circumferential opening covered by the bottom wall of the groove-shaped portion 28 in the intermediate sleeve 24 and its outer circumferential opening covered by the outer cylinder member 16, forms a tunnel-shaped flow path extending circumferentially. The tunnel-shaped flow path formed by the pair of throttling members 102 is interconnected in the circumferential direction. One circumferential end of these interconnected tunnel-shaped passages is connected to the first fluid chamber 38a, and the other circumferential end is connected to the second fluid chamber 38b. Thus, the slit-shaped portion 54 forms a throttling path 40 that interconnects the first fluid chamber 38a and the second fluid chamber 38b. The sidewall portion of the throttling passage 40 is integrally formed as a combination structure of four magnetic circuit forming members 104, magnetic circuit forming members 104, magnetic circuit forming members 104, and magnetic circuit forming members 104. Each magnetic circuit forming member 104 extends to a position on either side of the passage length direction (i.e., circumferential direction) of the throttling passage 40, beyond the end of the passage length direction of the throttling passage 40 in the circumferential direction.

[0122] The engine mount 100 equipped with such a throttling member 102 guides the magnetic flux of the magnetic field generated by the magnetic unit 58 through the energization of the coil 60 to the magnetic circuit forming member 104 in a substantially circumferential manner. The magnetic flux guided to the magnetic circuit forming member 104 is concentrated through the throttling passage 40, which is formed by the magnetic circuit forming member 104 on one side of the axis, the magnetic circuit forming member 104 on the other side of the axis, the magnetic flux concentration section 108 where the distance between the opposing magnetic circuit forming members 104 is shortened, and the opposing portion of the magnetic flux concentration section 108. As a result, the magnetic flux acts concentratedly on the magnetic functional fluid within the throttling passage 40, and the magnetic force with high magnetic flux density acts locally on the magnetic functional fluid, thus enabling effective control of the viscosity of the magnetic functional fluid. As a result, the flow resistance of the throttling passage 40 can be efficiently controlled, and the tuning frequency of the throttling passage 40 and even the vibration damping characteristics of the engine mount 100 can be adjusted or switched. Thus, according to the structure of this embodiment, compared with the first embodiment and the second embodiment, a larger circumferential magnetic flux can be guided to the throttling path 40 to exert a stronger magnetic force on the magnetic functional fluid, thereby enabling effective adjustment or switching of the anti-vibration characteristics with less power consumption.

[0123] exist Figure 17 In this paper, as a fourth embodiment of a fluid-sealed cylindrical vibration damping device with a structure according to the present invention, an engine mount 110 for a motor vehicle is shown.

[0124] The engine mount 110 has a throttling member 112. Also, Figure 18 As shown, the throttling member 112 is composed of a pair of magnetic circuit forming members 114. The magnetic circuit forming members 114 are made of a strongly magnetic material and are formed in a continuous ring shape throughout the entire circumference. Each magnetic circuit forming member 114 has a flux concentrating portion 116 that protrudes axially inward in a portion of its circumferential direction. The circumferential length of the flux concentrating portion 116 gradually decreases towards the protruding tip. In this embodiment, the circumferential end face of the flux concentrating portion 116 is formed as a conical surface, with a tapered shape where the cross-sectional area decreases towards the protruding tip.

[0125] The magnetic circuit forming member 114 is mounted in an outer sleeve state to the axial end of the intermediate sleeve 24. The magnetic circuit forming member 114 is fixed to the intermediate sleeve 24, for example, by pressing or a reduction machining process in the outer sleeve state. The magnetic circuit forming members 114 are respectively mounted at both axial ends of the intermediate sleeve 24. This pair of magnetic circuit forming members 114 are axially separated and opposite each other, and the magnetic flux concentrating portions 116 are circumferentially positioned relative to each other and axially spaced apart by a predetermined distance. In the throttling member 112, the pair of magnetic circuit forming members 114 are independently mounted in the intermediate sleeve 24. It should be noted that in this embodiment, the groove-shaped portion 28 of the intermediate sleeve 24 is filled with a closed rubber 118 integrally formed with the main rubber elastomer 18. Furthermore, the protruding portion of the closed rubber 118 protruding outward from the groove 28 enters between the opposing surfaces of a pair of magnetic circuit forming members 114, the portion of the magnetic circuit forming members 114 without a magnetic flux concentration portion 116, and the portion of the magnetic flux concentration portion 116. The pair of magnetic circuit forming members 114 abut against the protruding portion of the closed rubber 118 in the axial direction, thereby positioning the pair of magnetic circuit forming members 114 relative to the intermediate sleeve 24 in the axial direction.

[0126] like Figure 17 As shown, a magnetic circuit forming member 114 is installed on the intermediate sleeve 24, and an outer cylinder member 16 is installed on the magnetic circuit forming member 114 in an outer sleeve state. Thus, the magnetic circuit forming member 114 is held between the intermediate sleeve 24 and the outer cylinder member 16 radially. In addition, the inner peripheral opening of the slit-shaped portion 54 formed between the magnetic flux concentration portion 116 of the magnetic circuit forming member 114 and the axial direction of the magnetic flux concentration portion 116 is covered by the intermediate sleeve 24 through a sealing rubber 118, and the outer peripheral opening is covered by the outer cylinder member 16 through a sealing rubber layer 34, thereby forming a throttling passage 40 extending circumferentially using the slit-shaped portion 54.

[0127] In the engine mount 110 of this embodiment with such a structure, the magnetic flux of the magnetic unit 58 generating the magnetic field also acts on the magnetic functional fluid of the throttling passage 40 in a high-density state, concentrated by the magnetic flux concentration section 116 of the magnetic circuit forming member 114. Therefore, excellent vibration damping performance can be obtained by adjusting or switching the characteristics of the throttling passage 40, and power consumption can be reduced by suppressing the power required to generate the magnetic field.

[0128] In this embodiment, the magnetic circuit forming member 114 extends to a position circumferentially outward from the throttling flow path 40, and the magnetic circuit forming member 114 is formed as a continuous ring covering the entire circumference. Therefore, the circumferential magnetic flux is guided into the throttling flow path 40 by the magnetic circuit forming member 114, resulting in a stronger magnetic force that can effectively act on the magnetically functional fluid within the throttling flow path 40. Furthermore, in this embodiment, as... Figure 17 As shown, the magnetic circuit forming member 114 is positioned in the radial projection that overlaps with the magnetic pole forming portion in the magnetic yoke member 62 of the magnetic unit 58. The distance between the magnetic circuit forming member 114 and the magnetic pole forming portion in the magnetic yoke member 62 is shortened, thereby suppressing the leakage magnetic flux between the magnetic circuit forming member 114 and the magnetic yoke member 62.

[0129] 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, in the above embodiments, a structure in which magnetic circuit forming members 44 on both sides of the axial direction are provided with magnetic flux concentration portions 46 is described. However, a structure in which magnetic flux concentration portions 46 are provided on one magnetic circuit forming member 44 and not provided on the other magnetic circuit forming member 44 may also be adopted.

[0130] The flux concentrating section 46 may not have a tapered portion 48 with a continuously varying cross-sectional area toward the throttling passage 40 (in the embodiment, from the outer side of the support axis toward the inner side). For example, it may have a stepped shape where the length (circumferential) dimension of the throttling passage 40 varies in stages toward the throttling passage 40. Alternatively, the tapered portion 48 may be partially provided in the flux concentrating section 46 in the length and / or width direction of the throttling passage. For example, the front end of the flux concentrating section 46 on the throttling passage 40 side may be a tapered portion 48, and the base end of the flux concentrating section 46 away from the throttling passage 40 may be stepped. Furthermore, the flux concentrating section 46 may be formed such that, based on the length dimension of the throttling passage 40, the height (radial) dimension also decreases toward the throttling passage 40. In the conical section, both ends of the throttling passage 40 along the length of the passage can be formed as steps or cones, or only one end can be formed as a step or cone (i.e., a single slope).

[0131] The end of the flux concentration unit 46 on the throttling path 40 side does not necessarily need to have a surface extending along the length direction of the throttling path 40. For example, it can also be a sharp shape with a length direction dimension of approximately 0 for the throttling path 40.

[0132] The front end portion of the flux concentrating section 46 constituting the sidewall portion of the throttling path 40 may also have multiple portions along the length direction of the throttling path 40. It should be noted that when multiple flux concentrating sections 46 constitute the sidewall portion of the throttling path 40, preferably, the sum of the dimensions of the front end portions of the flux concentrating sections 46 along the length direction of the throttling path 40 is 60% or less, more preferably 40% or less, relative to the length dimension of the throttling path 40.

[0133] Preferably, the magnetic circuit forming members 44 disposed on the sidewall portions on both sides of the throttling passage 40 are independent of each other or connected to each other using a non-magnetic material connecting portion, but for example, they can also be an integral structure that is integrally connected at the circumferential ends. In short, as long as the magnetic force acting on the throttling passage 40 can be ensured, the magnetic circuit forming members 44 can also be connected using a strongly magnetic material.

[0134] In the above embodiment, an example is shown in which a pair of flux concentration units 46 constituting the sidewall portion of the throttling passage 40 are positioned relative to each other in the circumferential direction and are arranged opposite each other in the opposing direction (axial direction) of the sidewall portion of the throttling passage 40. However, for example, the flux concentration units 46 may be arranged at different positions relative to each other in the circumferential direction and may not be opposite each other in the opposing direction of the sidewall portion of the throttling passage 40. That is, when magnetic flux concentration sections 46 are provided on both sides of the throttling passage 40, magnetic flux concentration sections 46 of different shapes and sizes can be used. The front ends (ends on the throttling passage 40 side) of these magnetic flux concentration sections 46 on both sides can be arranged opposite each other at least partially in the throttling width direction (bracket axial direction) or they can be arranged opposite each other in an inclined direction relative to the throttling width direction (staggered in the throttling length direction) by being arranged at different positions in the throttling length direction.

[0135] In the above embodiments, a throttling passage 40 of a structure extending circumferentially is shown as an example. However, the throttling passage may extend circumferentially while being inclined relative to the axial direction, or extend circumferentially while meandering, or extend axially. It is not limited to a structure that extends circumferentially without being inclined relative to the axial direction.

[0136] In the above embodiment, an example is shown of a structure in which the magnetic unit 58 is mounted on the outer peripheral surface of the outer cylinder member 16. However, as long as the magnetic unit can exert a magnetic field on the magnetic flux concentration section 46 constituting the side wall portion of the throttling passage 40 in a selectable or controllable manner, it can be disposed, for example, on the inner peripheral side or inside of the inner shaft member, the outer cylinder member, the main body rubber elastomer, etc. For example, as shown in Japanese Patent Application Publication No. 2020-133700, the magnetic unit can also be disposed inside the inner shaft member. In addition, the housing space for the magnetic unit can be provided inside the outer cylinder member or inside the main body rubber elastomer, or it can be disposed on the inner periphery of the hollow inner shaft member. Furthermore, the coil of the magnetic unit does not necessarily need to be wound circumferentially throughout the entire circumference of the outer cylinder member; for example, it can be disposed only partially in the circumferential direction.

[0137] Explanation of reference numerals in the attached figures

[0138] 10: Engine mount (first embodiment of fluid-sealed cylindrical vibration damping device);

[0139] 12: Main body of anti-vibration device;

[0140] 14: Inner shaft components;

[0141] 16: Outer cylinder components;

[0142] 18: Main body rubber elastomer;

[0143] 20: Stopping components;

[0144] 22: Protrusion;

[0145] 24: Intermediate sleeve;

[0146] 26: Window area;

[0147] 28: Groove-shaped part;

[0148] 30: Pouch-like part;

[0149] 32: Flange-like portion;

[0150] 34: Sealing rubber layer;

[0151] 38: Fluid chamber;

[0152] 40: Streamline traffic flow;

[0153] 42: Throttling components;

[0154] 44: Magnetic circuit forming components;

[0155] 46: Flux Concentration Unit;

[0156] 48: Conical portion;

[0157] 50: Sidewall component;

[0158] 52: Connecting part;

[0159] 54: Slit-like portion;

[0160] 56: Rubber layer;

[0161] 58: Magnetic unit;

[0162] 60: Coil;

[0163] 62: Magnetic yoke component;

[0164] 66: Connector;

[0165] 70: Cylindrical cover component;

[0166] 72: Power unit;

[0167] 74: Vehicle body;

[0168] 80: Engine bracket (second embodiment of fluid-sealed cylindrical vibration damping device);

[0169] 82: Throttling component;

[0170] 86: Sidewall components;

[0171] 88: Flow path components;

[0172] 90: Connecting structural components;

[0173] 92: Fixing part;

[0174] 94: Connecting part;

[0175] 96: Screw;

[0176] 98: Gap;

[0177] 100: Engine mount (Third embodiment of fluid-sealed cylindrical vibration damping device);

[0178] 102: Throttling component;

[0179] 104: Magnetic circuit forming component;

[0180] 106: Connecting part;

[0181] 108: Flux Concentration Unit;

[0182] 110: Engine mount (fourth embodiment of fluid-sealed cylindrical vibration damping device);

[0183] 112: Throttling component;

[0184] 114: Magnetic circuit forming component;

[0185] 116: Flux Concentration Unit;

[0186] 118: Sealed rubber.

Claims

1. A fluid-sealed cylindrical vibration damping device (10, 80, 100, 110), wherein the inner shaft component (14) and the outer cylinder component (16) of the fluid-sealed cylindrical vibration damping device (10, 80, 100, 110) are elastically connected by a main body rubber elastomer (18), and multiple fluid chambers (38) sealed with fluid are configured to be interconnected through a throttling passage (40), wherein, The fluid sealed in the fluid chamber (38) is a magnetically functional fluid. The fluid-sealed cylindrical vibration damping devices (10, 80, 100, 110) are equipped with a magnetic unit (58) that generates a magnetic field by energizing. Magnetic circuit forming members (44, 104, 114) that are subjected to the magnetic field generated by the magnetic unit (58) are arranged on the sidewall portions of the opposite sides of the throttling passage (40), and At least one of the magnetic circuit forming members (44, 104, 114) disposed on the sidewall portions on both sides is provided with a magnetic flux concentration section (46, 108, 116), the magnetic flux concentration section (46, 108, 116) having a smaller dimension in the longitudinal direction of the throttling flow path (40) towards the inner side in the opposite direction. The sidewall portions on both sides of the throttling passage (40) are formed as a combination structure of the magnetic circuit forming member (44) and the sidewall members (50, 86) made of non-magnetic material, wherein the magnetic circuit forming member (44) partially constitutes the sidewall portion of the throttling passage (40) in the length direction.

2. The fluid-sealed cylindrical vibration damping device (10, 80, 100) according to claim 1, wherein, The magnetic circuit forming members (44, 104) disposed on the sidewall portions on both sides of the throttling passage (40) are independent members, but are connected to each other by means of connecting parts (52, 94, 106).

3. The fluid-sealed cylindrical vibration damping device (10, 80, 100) according to claim 2, wherein, The magnetic circuit forming members (44, 104) disposed on the sidewall portions on both sides of the throttling passage (40) are made of strongly magnetic material, and the connecting portions (52, 94, 106) are made of non-magnetic material.

4. The fluid-sealed cylindrical vibration damping device (10, 80, 100) according to claim 2 or 3, wherein, The magnetic circuit forming members (44, 104) disposed on the side wall portions on both sides of the throttling passage (40) are integrally formed with the connecting portions (52, 94, 106).

5. The fluid-sealed cylindrical vibration damping device (10, 80, 100) according to claim 2 or 3, wherein, The connecting parts (52, 94, 106) composed of separate components are later fixed to the magnetic circuit forming members (44, 104) disposed on the side wall portions on both sides of the throttling passage (40), thereby connecting the magnetic circuit forming members (44, 104) disposed on the side wall portions on both sides of the throttling passage (40).

6. The fluid-sealed cylindrical vibration damping device (10, 80, 100, 110) according to claim 1, wherein, The magnetic circuit forming members (44, 104, 114) disposed on the sidewall portions on both sides of the throttling passage (40) are formed into a shape that is symmetrical to each other.

7. The fluid-sealed cylindrical vibration damping device (10, 80, 100, 110) according to claim 1, wherein, The flux concentration section (46, 108, 116) in the magnetic circuit forming member (44, 104, 114) has a tapered portion whose length direction of the throttling passage (40) gradually decreases towards the inside of the opposite direction.

8. The fluid-sealed cylindrical vibration damping device (10, 80, 100, 110) according to claim 1, wherein, The magnetic circuit forming members (44, 104, 114) extend to at least one side of the throttling passage (40) along its length to a position further outward than the throttling passage (40).

9. The fluid-sealed cylindrical vibration damping device (100, 110) according to claim 8, wherein, The magnetic circuit forming components (104, 114) extend outward from both ends of the throttling passage (40) in the circumferential direction and are integrally formed into a ring extending circumferentially along the outer cylinder component (16).

10. The fluid-sealed cylindrical vibration damping device (100, 110) according to claim 9, wherein, An intermediate sleeve (24) is fixed to the outer periphery of the main rubber elastomer (18). The magnetic circuit forming member (104, 114), which is formed in a ring shape, is installed in the intermediate sleeve (24) in an outer sleeve state, and the outer cylinder member (16) is installed in the magnetic circuit forming member (104, 114) in an outer sleeve state.

11. The fluid-sealed cylindrical vibration damping device (10, 80, 100, 110) according to claim 1, wherein, The front end face of the inner side of the magnetic flux concentration part (46, 108, 116) of the magnetic circuit forming member (44, 104, 114) in the opposite direction has a dimension in the length direction of the throttling passage (40) of less than 60% of the total length of the throttling passage (40).

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