Damper Device

Abstract

To provide a small damper device which uses a magnetic viscous fluid and is capable of dealing with a wide range of load.SOLUTION: An MR damper 1 includes: a cylinder 6 in which a magnetic viscous fluid whose viscosity is changed according to application of a magnetic field is sealed; a piston 7 which partitions the cylinder 6 into a first cell 8 and a second cell 9 while moving in the cylinder; a fluid passage 30 which communicates between the first cell 8 and the second cell 9; and electric magnets 3 and 5 which have an electromagnetic coil 11 and iron core pipes 12 and 14, and feeds an electric current to the electromagnetic coil 11 for applying the magnetic field to the fluid passage 30 and increasing flow resistance of the magnetic viscous fluid in the fluid passage 30, so that moving resistance is added to an object connected to the piston 7. In the MR damper, the fluid passage 30 is arrange while facing one end sections of the iron core pipes 12 and 14, and there are provided a first fluid passage 31 to which the magnetic field is applied by the electromagnetic coil 11 and second fluid passages 32 and 33 which pass through the iron core pipes 12 and 14.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a damper device using a magnetorheological fluid. [Background technology]

[0002] In recent years, damper devices using magnetorheological fluids (hereinafter referred to as MR dampers) have been developed. Magnetorheological fluids are fluids whose viscosity increases when a magnetic field is applied.

[0003] Patent Document 1 discloses a piston-cylinder type MR damper. The MR damper in Patent Document 1 has a configuration in which compartments are provided on both sides of a piston that moves within a cylinder, and the compartments on both sides are connected and sealed by a narrow-diameter communication passage, with an electromagnet disposed around the communication passage. The electromagnet applies a magnetic field to increase the viscosity of the magnetorheological fluid, thereby increasing the flow resistance of the magnetorheological fluid moving through the communication passage. This suppresses the movement of the piston and enables vibration damping of an object connected to the piston. Furthermore, by changing the current supplied to the electromagnet, the flow resistance of the magnetorheological fluid can be changed, making it possible to easily change the damping force. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-168283 Summary of the Invention [Problem to be solved by the invention]

[0005] Damper devices using a cylinder-type magnetorheological fluid, such as that described in Patent Document 1, are often used in applications that involve large loads, such as automobile suspension systems and vibration control for buildings. However, in order to handle large loads, it is necessary to install a large number of electromagnets or to make them larger, which poses a problem of increasing the size of the damper device.

[0006] Furthermore, although it is possible to miniaturize the damper device by miniaturizing the electromagnet, this reduces the controllable range of flow resistance, which results in a narrower range in which the damping force can be changed, i.e., the range in which the load can be accommodated.

[0007] The present invention has been made in view of the above circumstances, and its object is to provide a damper device that uses a magnetorheological fluid and is small and can accommodate a wide range of loads. [Means for solving the problem]

[0008] In order to achieve the above object, the damper device of the present invention includes a cylinder filled with a magnetorheological fluid whose viscosity changes in response to the application of a magnetic field, a movable body that moves within the cylinder and divides the cylinder into a first compartment and a second compartment, and a fluid passage that connects the first compartment and the second compartment; Cylindrical Electromagnetic coil and inserted into the electromagnetic coil and an electromagnet having an iron core, wherein current is passed through the electromagnetic coil to apply a magnetic field to the fluid passage, thereby increasing the flow resistance of the magnetorheological fluid in the fluid passage and adding resistance to movement of the moving body. The fluid passage comprises a first fluid passage disposed facing one end of the iron core and to which a magnetic field is applied by the electromagnetic coil, and a second fluid passage passing through the iron core. The cross-sectional area of ​​the first fluid passage is smaller than that of the second fluid passage. It is characterized by:

[0009] Preferably, the second fluid passage has a flow path connecting one end of the first fluid passage and the first compartment, and a flow path connecting the other end of the first fluid passage and the second compartment.

[0010] Preferably, three or more of the electromagnets are arranged in parallel, the first fluid passage is arranged along one end of the iron cores of the parallel electromagnets, and the second fluid passage is arranged so as to pass through the interiors of the iron cores of the electromagnets located at both ends of the parallel electromagnets.

[0011] Preferably, a metal plate that serves as a yoke for the electromagnet is provided facing the first fluid passage.

[0012] Preferably, the first fluid passage is formed between a plurality of stacked plates.

[0013] Preferably, the first fluid passage and the second fluid passage are connected at an angle.

[0014] Preferably, a flow path cross-sectional area changing means for changing the flow path cross-sectional area of ​​the first fluid passage may be provided in the vicinity of a connection portion of the first fluid passage with the second fluid passage.

[0015] Preferably, the first fluid passage is provided inside the yoke and the second fluid passage is provided inside the iron core, the iron core is inserted into the yoke and connected, and the flow passage cross-sectional area changing means changes the flow passage cross-sectional area of ​​the first fluid passage by changing the insertion amount of the iron core into the yoke and connecting it. [Effects of the Invention]

[0016] According to the present invention, the movement of a moving body is suppressed by the flow resistance of the magnetorheological fluid passing through the fluid passage. This makes it possible to suppress the vibration of a damped body connected to the moving body, for example. Furthermore, by applying a magnetic field to the first fluid passage by the electromagnet, the viscosity of the magnetorheological fluid passing through the fluid passage can be increased, thereby increasing the flow resistance. Therefore, by energizing the electromagnetic coil of the electromagnet, the movement of the moving body can be easily and strongly suppressed.

[0017] The fluid passage further includes a first fluid passage disposed facing one end of the iron core of the electromagnet and to which a magnetic field is applied by the electromagnetic coil, and a second fluid passage passing through the inside of the iron core. The cross-sectional area of ​​the first fluid passage is smaller than that of the second fluid passage. Therefore, not only does the flow resistance of the magnetorheological fluid passing through the first fluid passage increase when current is applied to the electromagnetic coil, but a magnetic field is also applied when the magnetorheological fluid passes through the second fluid passage in the iron core, causing a concentrated increase in the flow resistance at the connection point with the first fluid passage.

[0018] This allows the small electromagnet to significantly increase the viscosity of the magnetorheological fluid passing through the fluid passage, thereby significantly increasing the flow resistance, making it possible to create a damper device that can accommodate a wide range of loads. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a perspective view showing the shape of an MR damper according to one embodiment of the present invention. [Figure 2] FIG. 2 is a vertical cross-sectional view showing the internal structure of the MR damper of the present embodiment. [Figure 3] 3 is an explanatory diagram showing the shape of a first fluid passage in the MR damper of the present embodiment. FIG. [Figure 4] 3 is a vertical cross-sectional view showing the structure of a connection portion between an iron core pipe and a yoke in the MR damper of the present embodiment. FIG. [Figure 5] 2 is an explanatory diagram of a fluid path and a generated magnetic field in the MR damper of the present embodiment. FIG. [Figure 6] FIG. 10 is a schematic structural diagram of an MR damper according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0021] Fig. 1 is a perspective view showing the shape of an MR damper 1 (damper device) according to one embodiment of the present invention. Fig. 2 is a vertical cross-sectional view showing the internal structure of the MR damper 1 according to this embodiment. Note that Fig. 1 omits the illustration of the windings of an electromagnetic coil, which will be described later.

[0022] The MR damper is a damper that uses magnetorheological fluid, which is a fluid containing, for example, iron powder, and whose viscosity increases when a magnetic field is applied.

[0023] MR dampers can easily change their damping performance by applying a magnetic field using an electromagnet to increase the viscosity of the magnetorheological fluid. MR dampers are used, for example, in vehicle suspension systems and building vibration isolation devices.

[0024] The MR damper 1 of this embodiment is a relatively small one that is used in, for example, a shift device of a vehicle.

[0025] 1 and 2, the MR damper 1 of this embodiment is a piston-cylinder type MR damper. The MR damper 1 includes a piston cylinder 2 and three electromagnets 3, 4, and 5.

[0026] The piston cylinder 2 is divided into a first compartment 8 and a second compartment 9 by a piston 7 (moving body) that is movable inside a cylindrical cylinder 6 having a rectangular parallelepiped outer shape.

[0027] The electromagnets 3, 4, and 5 each include an electromagnetic coil 11 formed in a substantially cylindrical shape by winding an electric wire around a bobbin 10, and iron cores 12, 13, and 14 inserted into the bobbin 10. The electromagnets 3, 4, and 5 are arranged adjacent to the cylinder 6 and aligned in the axial direction of the cylinder 6.

[0028] The iron cores 12, 13, and 14 have one end supported by one side wall 15 of the cylinder 6, extend in a direction perpendicular to the axial direction of the cylinder 6 and are supported at the other end by a yoke 20 in the form of a rectangular plate.

[0029] The yoke 20 is disposed parallel to and spaced apart from one side wall 15 of the cylinder 6, and is fixed to the cylinder 6 by, for example, four bolts 21. That is, three electromagnets 3, 4, and 5 are disposed side by side in the axial direction of the cylinder 6 between the one side wall 15 of the cylinder 6 and the yoke 20.

[0030] Of the three lined-up electromagnets 3, 4, and 5, the iron core 13 of the central electromagnet 4 is cylindrical, while the iron cores 12 and 14 of the outer electromagnets 3 and 5 are cylindrical. The iron cores 12 and 14 of the outer electromagnets 3 and 5 will hereinafter be referred to as iron core pipes 12 and 14.

[0031] The yoke 20 is configured by sandwiching one spacer 24 between two rectangular flat plates 22, 23, and fastening them together at the four corners with screws 25, for example. The two plates 22, 23 and the spacer 24 have approximately the same outer shape. The spacer 24 is made of a non-magnetic material such as aluminum and has a thickness of, for example, just under 1 mm, and as shown in FIG. 3, is hollowed out so that its interior extends in the longitudinal direction. By sandwiching the spacer 24 between the two plates 22, 23, the hollowed-out portion of the spacer 24 becomes a first fluid passage 31, which is an internal space just under 1 mm thick.

[0032] Of the two plates 22, 23, the cover plate 22 on the cylinder 6 side is made of a non-magnetic material such as aluminum and has a thickness of several millimeters. The yoke plate 23 on the opposite side from the cylinder 6 is the yoke body and is made of a magnetic material such as a relatively thick iron plate (metal plate). The cover plate 22 is provided with holes against which the other end of the iron core 13 of the electromagnet 4 located in the center abuts, and into which the other ends of the iron core pipes 12, 14 are inserted. The two holes in the cover plate 22 communicate near both ends of the first fluid passage 31 in the yoke 20. In other words, the holes in the iron core pipes 12, 14 communicate via the first fluid passage 31 in the yoke 20.

[0033] In the MR damper 1, a fluid passage 30 that connects the first chamber 8 and the second chamber 9 is formed.

[0034] The fluid passage 30 is made up of a first fluid passage 31 which is an internal space formed in the yoke 20, and second fluid passages 32, 33 which are holes in the core pipes 12, 14.

[0035] The second fluid passage 32 provided in the core pipe 12 is configured to connect one end of the first fluid passage 31 to the first compartment 8. The second fluid passage 33 provided in the core pipe 14 is configured to connect the other end of the first fluid passage 31 to the second compartment 9.

[0036] The first compartment 8, the second compartment 9 and the fluid passage 30 of the cylinder 6 are sealed from the outside, and the above-mentioned magnetorheological fluid is sealed in without any gaps.

[0037] A piston rod 35 is connected to the piston 7 inside the cylinder 6. The piston rod 35 protrudes outward from both ends of the cylinder 6. The cylinder 6 is fixed to, for example, a base, and the end of the piston rod 35 is connected to an object to which movement resistance is applied.

[0038] FIG. 4 is a vertical cross-sectional view showing the shape of the connection between the iron core pipes 12 and 14 and the yoke 20. As shown in FIG.

[0039] Thin plate-like seal members 41 are provided between the cover plate 22 and the spacer 24, and between the yoke plate 23 and the spacer 24. The seal members 41 have approximately the same outer shape as the spacer 24 and are hollowed out in the same shape as the first fluid passage 31.

[0040] The ends of the core pipes 12, 14 on the yoke 20 side are thinned by grinding the outer wall surface side, thereby forming protrusions 42 that protrude from the inner wall surface side at the ends of the core pipes 12, 14, and forming steps 43 on the outer periphery side of the protrusions 42.

[0041] In addition, a relatively thick, elastic ring-shaped seal member 44 made of rubber or the like is sandwiched between the cover plate 22 and the step 43 of the iron core pipes 12, 14 to prevent fluid from leaking to the outside at the connection between the iron core pipes 12, 14 and the yoke 20.

[0042] The insertion amount of the iron core pipes 12, 14 into the yoke 20 can be changed by changing the tightening amount of the bolts 21. For example, by increasing the tightening amount of the bolts 21, the gap between the tips of the protruding portions 42 of the iron core pipes 12, 14 and the surface 23a of the yoke plate 23 on the side of the first fluid passage 31 becomes smaller, as indicated by the two-dot chain line in Figure 4, and the flow path cross-sectional area of ​​the first fluid passage 31 near the connection between the iron core pipes 12, 14 and the yoke 20 decreases.

[0043] Alternatively, several types of spacers 24 with different thicknesses may be prepared in advance, and the cross-sectional area of ​​the flow path of the first fluid passage 31 may be changed by changing the thickness of the spacer 24 by replacing it.

[0044] The structure for changing the flow path cross-sectional area of ​​the first fluid passage 31 by the protrusions 42 and the like near the connection between the iron core pipes 12, 14 and the yoke 20 corresponds to the flow path cross-sectional area changing means of the present invention.

[0045] With the above-described configuration, when the piston 7 of the MR damper 1 moves left or right, the magnetorheological fluid moves from one of the first compartment 8 and the second compartment 9 to the other through the fluid passage 30 (the first fluid passage 31 and the second fluid passages 32 and 33), as indicated by the dashed line in FIG. 5 . At this time, the magnetorheological fluid passes through the first fluid passage 31, which is a space slightly less than 1 mm thick, and the movement of the magnetorheological fluid is suppressed by the flow resistance of the first fluid passage 31. Note that the thickness of the space that becomes the first fluid passage 31, which is slightly less than 1 mm, is just an example, and the range of thickness that can be set may be wider. For example, the thickness range is 0.2 mm to 2 mm, and more preferably 0.3 mm to 1 mm.

[0046] This restricts the movement of the piston 7, and makes it possible to apply movement resistance to the object connected to the piston rod 35 relative to the base connected to the cylinder 6.

[0047] Furthermore, by supplying, for example, a direct current to the electromagnetic coils 11 of the electromagnets 3, 4, and 5, a magnetic field is generated in and around the iron cores 12, 13, and 14, as shown by the dashed dotted line in Fig. 5. By passing current through the electromagnets 3, 4, and 5 so that the electromagnets 3, 5 and the electromagnet 4 generate magnetic fields in opposite directions, a magnetic field is applied to the iron cores 12, 13, and 14 and around them, thereby increasing the viscosity of the magnetorheological fluid passing through the first fluid passages 31 arranged facing the ends of the iron cores 12, 13, and 14 of the electromagnets 3, 4, and 5, and thereby increasing the flow resistance. Therefore, by passing current through the electromagnets 3, 4, and 5, the movement resistance of the piston 7 can be increased.

[0048] Furthermore, the fluid passage 30 for the magnetorheological fluid connecting the first compartment 8 and the second compartment 9 includes not only the first fluid passage 31 but also the second fluid passages 32 and 33 that pass through the iron core pipes 12 and 14 of the electromagnets 3 and 5. Therefore, when the electromagnetic coils 11 of the electromagnets 3 and 5 are energized, a magnetic field is also applied when the fluid passes through the second fluid passages 32 and 33, further increasing the flow resistance near the junction between the second fluid passages 32 and 33 and the first fluid passage 31. Furthermore, by providing the second fluid passages 32 and 33 inside the iron core pipes 12 and 14, a more vertical magnetic field can be effectively applied. The area where the viscosity of the magnetorheological fluid increases when the electromagnets 3, 4, and 5 are energized is indicated by a two-dot chain line in FIG. 5.

[0049] As a result, the small electromagnets 3, 4, and 5 can greatly increase the flow resistance of the magnetorheological fluid passing through the fluid passage 30, and further increase the movement resistance of the piston 7.

[0050] Furthermore, in this embodiment, a yoke plate 23, which is a metal plate, is provided on the outside (opposite side from the cylinder 6) facing the first fluid passage 31, and this yoke plate 23 serves as the yoke of the electromagnets 3, 4, and 5. Therefore, the magnetic field generated by the electromagnets 3, 4, and 5 can be further concentrated facing the first fluid passage 31, particularly near the connection between the first fluid passage 31 and the second fluid passage 32, and the flow resistance of the magnetorheological fluid can be further increased.

[0051] Furthermore, the yoke 20 is configured by stacking a plate 22, a spacer 24, and a plate 23, and the first fluid passage 31 is formed between the plates 22 and 23. Therefore, by replacing the spacer 24 sandwiched between the plates 22 and 23 with one of a different thickness, the flow path cross-sectional area of ​​the first fluid passage 31 can be easily changed. This makes it possible to easily change the settable range of the movement resistance of the piston 6, and therefore the settable range of the damping force of the MR damper 1, to different specifications.

[0052] In this embodiment, three electromagnets 3, 4, and 5 are arranged side by side on one side wall of the cylinder 6, the first fluid passage 31 is arranged along one end of the electromagnetic coils 11 of the parallel electromagnets 3, 4, and 5, and the second fluid passages 32 and 33 are arranged so as to pass through the insides of the iron core pipes 12 and 14 of the electromagnets 3 and 5 located at both ends of the parallel electromagnets 3, 4, and 5, respectively.

[0053] Therefore, the three electromagnets 3, 4, and 5, and the fluid passage 30 for the magnetorheological fluid connecting the first compartment 8 and the second compartment 9, together with the cylinder 6, can be configured compactly.

[0054] Furthermore, the first fluid passage 31 and the second fluid passages 32 and 33 are connected at a 90-degree angle. Therefore, flow resistance increases when the magnetorheological fluid passes through this connection. In particular, because the cross-sectional area of ​​the first fluid passage 31 is relatively small, the flow resistance of the magnetorheological fluid increases significantly when it flows from the second fluid passages 32 and 33 into the first fluid passage 31.

[0055] Furthermore, since a magnetic field is applied in the second fluid passages 32, 33, the viscosity of the magnetorheological fluid is increased before it flows from the second fluid passages 32, 33 into the first fluid passage 31, thereby significantly increasing the flow resistance when it flows from the second fluid passages 32, 33 into the first fluid passage 31.

[0056] Furthermore, in this embodiment, the insertion amount of the iron core pipes 12, 14 into the yoke 20 can be easily changed by changing the tightening amount of the bolts 21. Changing the insertion amount of the iron core pipes 12, 14 into the yoke 20 can easily change the flow path cross-sectional area of ​​the first fluid passage 31 near the connection between the yoke 20 and the iron core pipes 12, 14, i.e., near the connection between the first fluid passage 31 and the second fluid passages 32, 33. Therefore, with a compact and simple configuration, the flow resistance of the magnetorheological fluid when passing near the connection between the first fluid passage 31 and the second fluid passages 32, 33 can be easily changed.

[0057] Furthermore, by changing the insertion amount of the iron core pipes 12, 14 into the yoke 20 and narrowing the flow path width of the first fluid passage 31 near the connection between the first fluid passage 31 and the second fluid passages 32, 33, the magnetic flux density of the electromagnets 3, 4, 5 in the narrowed flow path portion of the magnetorheological fluid increases, and the flow resistance of the magnetorheological fluid can be further increased due to a further increase in the viscosity of the magnetorheological fluid and an increase in shear resistance.

[0058] In this way, by changing the insertion amount of the iron core pipes 12, 14 into the yoke 20, the increase in the flow resistance of the magnetorheological fluid and the increase in the magnetic flux density of the magnetic field applied to the magnetorheological fluid are combined, making it possible to significantly increase the flow resistance of the magnetorheological fluid, and making it possible to easily and significantly change the movement resistance of the piston 7 in the MR damper 1.

[0059] Furthermore, since the configuration changes the flow path cross-sectional area of ​​the first fluid passage 31, which has a small flow path cross-sectional area immediately after the fluid passage 30 bends from the second fluid passages 32, 33 toward the first fluid passage 31, the flow resistance can be changed significantly even if the flow path cross-sectional area is changed to a smaller area.

[0060] For example, when comparing this embodiment with a comparative example that does not have the second fluid passages 32, 33 inside the electromagnets 3, 5, such as when an electromagnet is provided outside the second fluid passages 32, 33 rather than around them to apply a magnetic field, more specifically a comparative example that has a structure in which a magnetic field is applied only to the first fluid passage 31 and in which other conditions such as the flow path cross-sectional area, length, and connection angle of the first fluid passage 31 and the second fluid passages 32, 33, the number of turns of the electromagnetic coil 11 in the electromagnets 3, 4, 5, and the current flowing therethrough are the same as in this embodiment, it is found that providing a flow path (second fluid passages 32, 33) inside the iron cores of the electromagnets 3, 5 as in this embodiment can greatly increase the movement resistance of the piston 7 by increasing the current flowing through the electromagnetic coil 11.

[0061] In this way, by providing the second fluid passages 32, 33 inside the iron core pipes 12, 14 of the electromagnets 3, 5, it is possible to greatly change the movement resistance of the piston 7 in response to changes in the current of the electromagnets 3, 4, 5. In particular, by combining a configuration in which the second fluid passages 32, 33 are connected at a 90-degree angle to the first fluid passage 31, which has a small flow path cross-sectional area, it is possible to more greatly change the movement resistance of the piston 7 in response to changes in the current of the electromagnets 3, 4, 5. Therefore, it is possible to provide an MR damper 1 that is small in size yet can greatly change the movement resistance (damping force) in response to a wide range of applied loads.

[0062] This concludes the description of the embodiments, but the present invention is not limited to the above-described embodiments. For example, in the above-described embodiments, the present invention is applied to a piston-cylinder type MR damper 1, but the present invention can also be applied to a rotary-cylinder type MR damper. For example, as shown in Figure 6, an MR damper 50 (damper device) can be configured by providing a unit in which electromagnets 3, 4, and 5, a first fluid passage 31, and second fluid passages 32 and 33 as in this embodiment are arranged in a fluid passage 54 connecting two compartments 52 and 53 of a rotary cylinder 51.

[0063] Furthermore, although this embodiment is provided with three electromagnets 3, 4, and 5, three or more electromagnets may be provided, or only the electromagnets 3 and 5 at both ends may be provided. When only the electromagnets 3 and 5 at both ends are provided, the magnetic field lines of the electromagnets 3 and 5 pass through the same iron core pipes 12 and 14, so the direction of the DC current supplied to the electromagnetic coils 11 of the electromagnets 3 and 5 may be set so as not to cancel out the magnetic fields.

[0064] In addition, in each of the above-described embodiments, the detailed structure of each component may be changed as appropriate. For example, the shape of the first fluid passage 31 may be changed as appropriate depending on the required specifications of the MR damper, such as the movement resistance (damping force) when the current is not applied and when the current is applied.

[0065] The above-described MR damper 1 is also used in a transmission shift device as an actuator for providing a clicking sensation when the shift lever is moved to each position. This allows the shift lever operation feeling to be freely and easily changed. However, the MR damper 1, 50 of this embodiment may also be used for vibration control. The present invention can be widely applied to MR dampers used for various purposes other than transmission shift devices. [Explanation of symbols]

[0066] 1.50 MR damper (damper device) 3, 5 Electromagnets 6 cylinders 7 Piston (moving body) 8. First Chamber 9. Second Chamber 11 Electromagnetic coil 12, 14 Iron core pipe (iron core) 22 Cover plate (plate) 23 Yoke Plate (Plate, Yoke) 24 spacer 30, 54 Fluid passage 31 1st fluid passage 32, 33 2nd fluid passage 42 Protrusion (flow path cross-sectional area changing means)

Claims

1. a cylinder filled with a magnetorheological fluid whose viscosity changes in response to the application of a magnetic field; a moving body that moves within the cylinder and divides the cylinder into a first compartment and a second compartment; a fluid passageway communicating the first compartment with the second compartment; an electromagnet having a cylindrical electromagnetic coil and an iron core inserted into the electromagnetic coil, a damper device that applies resistance to movement of the moving body by applying a magnetic field to the fluid passage by energizing the electromagnetic coil and increasing the flow resistance of the magnetorheological fluid in the fluid passage, The fluid passage is a first fluid passage disposed facing one end of the iron core and to which a magnetic field is applied by the electromagnetic coil; a second fluid passage passing through the iron core, The cross-sectional area of ​​the first fluid passage is smaller than that of the second fluid passage. A damper device characterized by:

2. The second fluid passage has a flow path connecting one end of the first fluid passage and the first compartment, and a flow path connecting the other end of the first fluid passage and the second compartment. The damper device according to claim 1 .

3. Three or more electromagnets are arranged in parallel, the first fluid passage is disposed along one end of the parallel-arranged iron cores of the electromagnets; The second fluid passage is arranged so as to pass through the insides of the iron cores of the electromagnets located at both ends of the electromagnets arranged in parallel. The damper device according to claim 2 .

4. A metal plate serving as a yoke for the electromagnet is provided facing the first fluid passage. The damper device according to any one of claims 1 to 3.

5. 5. The damper device according to claim 1, wherein the first fluid passage is formed between a plurality of stacked plates.

6. The first fluid passage and the second fluid passage are connected at an angle. The damper device according to any one of claims 1 to 5.

7. a flow passage cross-sectional area changing means for changing the flow passage cross-sectional area of ​​the first fluid passage in a position near a connection portion of the first fluid passage with the second fluid passage; The damper device according to claim 6 .

8. the first fluid passage is provided inside the yoke, and the second fluid passage is provided inside the iron core, and the iron core is inserted into and connected to the yoke; The flow passage cross-sectional area changing means changes the flow passage cross-sectional area of ​​the first fluid passage by changing the insertion amount of the iron core into the yoke and connecting the iron core. The damper device according to claim 7 .

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