Opening plate for motor mounting filled with magnetorheological fluid

Abstract

Orifice plate device for a motor mount filled with a magnetorheological fluid, the orifice plate device comprising a coil device (40) having a coil wound thereon and having an annular shape, a core device unit (20, 30) which encloses the coil device (40) and which is formed in a disc-like shape and which defines a flux path, an upper passage (52a) thereof being arranged in an upper surface of the core device unit (20, 30) and a lower passage (12a) thereof being arranged in a bottom surface of the core device unit (20, 30), the flux path being formed annularly around the circumference of the coil device (40), and a flow path separator (60) installed between the upper passage (52a) and the lower passage (12a) so as to allow unidirectional circulation for the magnetorheological fluid passing through the flow path.

Description

BACKGROUND OF THE INVENTIONField of the InventionThe present invention relates to a (throttle) orifice plate mounted within a hydraulic motor mount using a magnetorheological (MR) fluid (or fluid), and more particularly relates to an orifice plate formed such that a magnetic field perpendicular to the flow direction of MR fluid is across all portions of the flow path through which the MR fluid flows and formed such that the flow path allows only unidirectional flow along a periphery of a coil device at the inside and outside of the coil device, respectively.DESCRIPTION OF THE RELATED ARTIn order to damp the vibration of an engine, the engine is mounted in the engine compartment of the vehicle body via engine mounts. Motor mounts that are commonly used are rubber mounts that use the elasticity of a rubber material and hydraulic mounts that are filled with a liquid and use a viscosity resistance of the movement of the liquid to damp vibration.Among these, the hydraulic engine mount is configured to attenuate vibrations in both the high frequency range and the low frequency range, and is widely used in many kinds of vehicles.FIG. 1 illustrates a cross section of a hydraulic engine mount having a conventional structure. The hydraulic engine mount holds hydraulic fluid in an internal space defined by an insulator 2 and a diaphragm 7, and the internal space has an orifice plate 4 installed therein and is divided into an upper liquid chamber 3 and a lower liquid chamber 6.The orifice plate 4 has a flow path 5 along an inner diameter thereof so that hydraulic fluid can flow therethrough, and has a decoupler selectively mounted at the center thereof. A bolt 1 coupled to the insulator 2 is coupled to a motor bracket. Thereby, the insulator 2 formed of an elastic material is repeatedly compressed and elastically restored by a change in the loads and by vibrations acting on the bolt 1, and the hydraulic fluid flows through the flow path 5 into the upper liquid chamber 3 and the lower liquid chamber 6.The hydraulic mount may be filled with an MR fluid rather than a general hydraulic fluid. Magnetorheological (MR) fluid is a suspension having fine magnetic particles mixed with a synthetic hydrocarbon liquid and having the property that shear stress varies depending on whether a magnetic field is applied in the vicinity and according to the strength of the applied magnetic field.Accordingly, an orifice plate 4' of a hydraulic mount filled with MR fluid as shown in Fig. 2 has a flow path 5' vertically formed therein, and a coil 8 is additionally installed to apply a magnetic field close to the flow path 5' through which the MR fluid passes. By controlling the amount of current applied to the coil 8, the dynamic stiffness and damping characteristics of a mount become controllable according to the conditions in which a vehicle is running.When a magnetic field is not applied, the MR fluid exhibits flow characteristics similar to those of general hydraulic fluid, but when a magnetic field is applied nearby, the particles are arranged in columns so as to change the flow characteristics of the fluid.That is, the shear stress of the MR fluid is determined as a value that is a multiple of the viscosity and the shear rate when a magnetic field is not applied, and when a magnetic field is applied, the shear stress of the MR fluid becomes the value (the multiple of the viscosity and the shear rate) to which a flow shear stress (e.g., additive shear stress) is added. The yield shear stress increases in proportion to the intensity of the applied magnetic field.As shown in FIG. 2, the direction in which the magnetic field is applied should be perpendicular to the flow direction of the MR fluid in order to orient the particles in the MR fluid perpendicular to the flow direction. However, in related art methods, while a magnetic field perpendicular to the flow direction of the MR fluid is formed in the region "A" and the region "C", in a configuration in which a coil is disposed at a certain distance from a side of the flow path, the magnetic field is formed in the region "B" in a parallel direction (to the flow direction of the MR fluid) and does not pass through the MR fluid, thereby reducing the control efficiency.Although the decreased control efficiency can be recovered by increasing the current applied to the coil or by forming a longer flux path, this causes a disadvantage of an increase in size, thereby also increasing the amount of heat generated.The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.For example, DE 698 08 600 T2 discloses an orifice plate device which is filled with a magnetorheological fluid, comprising: a coil device which comprises a coil wound thereon and which has an annular shape, and a core device unit which encloses the coil device.BRIEF DESCRIPTION OF THE INVENTIONVarious aspects of the present invention are directed to providing a (orifice) plate structure that can bypass the above restrictions and more efficiently control the flow characteristics of MR fluid.The present invention provides an orifice plate device according to claims 1 and 9. Further embodiments of the device are described in the respective dependent claims.According to an aspect of the invention, the orifice plate device for motor mounting filled with a magnetorheological fluid may include a coil device having a coil wound thereon and having an annular shape, a core device unit accommodating the coil device and formed in a disc-like shape and defining a flow path, an upper passage thereof being disposed in an upper surface of the core device unit and a lower passage thereof being disposed in a bottom surface of the core device unit, the flow path being annularly formed around the circumference of the coil device, and a flow path separator installed between the upper passage and the lower passage so as to allow unidirectional circulation for the magnetorheological fluid passing through the flow path.According to another aspect, an orifice plate device for motor mounting filled with a magnetorheological fluid may include a coil device having a coil wound thereon and having an annular shape, a core device unit accommodating the coil device and formed in a disc-like shape and defining at least two flow paths, at least two upper passages being formed in an upper surface of the core device unit, and at least two lower passages being disposed in a bottom surface of the core device unit, the at least two flow paths being formed annularly around the periphery of the coil device.The at least two flow paths formed at two locations within the core device unit and which are fluid-separated from each other may include an inner flow path formed at an inner portion of the coil device unit and an outer flow path formed at an outer portion of the coil device, wherein first and second flow path separators are installed adjacent to the inner flow path and the outer flow path, respectively, to change a flow direction of the magnetorheological fluid.The core device unit may include a lower plate having a circular plate shape and having a protrusion portion formed at a center thereof and first and second lower passages corresponding to the inner and outer flow paths, a lower core having a circular plate shape and installed above the lower plate and having a first passage opening formed therein and communicating with the second lower passage of the outer flow path, and a first opening formed at a center thereof, wherein an inner edge is formed protruding upward along an inner periphery of the first opening, and wherein an outer edge is formed protruding upward along an outer periphery of the lower core, and an upper core having a circular plate shape, and which is installed above the lower core and which has a second passage opening formed therein and a second opening formed in a center thereof, wherein an inner edge is formed protruding downward along an inner periphery of the second opening, and wherein an outer edge is formed protruding downward along an outer periphery of the upper core so that the protruding portion is coupled to the inner edge of the second opening, the second passage opening being in fluid communication with the first lower passage through a first space formed between the inner edge of the lower core and the inner edge of the upper core, the first passage opening being in fluid communication with a second space formed between the outer edge of the upper core and the outer edge of the lower core, and wherein the core means is disposed between the lower core and the upper core, and an upper plate having a circular plate shape and installed above the upper core and having first and second upper passages of the inner flow path and the outer flow path, wherein the second passage opening of the upper core is in fluid communication with the first upper passage and the second space is in fluid communication with the second upper passage.The first flow path separator may be disposed in the first space between the first lower passage and the second passage opening.The second flow path separator may be disposed in the second space between the first passage opening and the second upper passage.The coil means may be installed between the inner periphery of the lower core and the outer periphery of the upper core.The lower core and the upper core may be made with (e.g., from) a material having a higher relative permeability than the lower plate and the upper plate.Two or more flow path separators may be installed in the inner flow path or the outer flow path to prevent the fluid communication therebetween (e.g., the flow paths, e.g., the flow path separators), and an upper passage and a lower passage may be additionally formed according to the number of the flow path separators.The exemplary embodiments of the present invention configured as described above have the effect of making it possible to more effectively control the flow characteristics of the MR fluid by increasing the effective area (an area in which the flow direction of the MR fluid and the magnetic field are perpendicular) affected by the magnetic field by circulating the flow path only in one direction along the circumference of the coil device. The orifice plate according to exemplary embodiments in the present invention may have flow paths formed at two locations so that the MR fluid can flow more quickly and a larger amount of the MR fluid can be controlled simultaneously.In addition, the flux paths according to exemplary embodiments of the present invention are structures in which an upper of an outer flux path and a lower of an inner flux path are perpendicularly protruded from the coil means, so that the MR fluid flowing at the protrusion portions forms a right angle with the magnetic field along the entire circumference of the flux paths, thereby enabling a further increase in control performance (see the protrusion portions represented by arrows in FIG. 3 ).Accordingly, a smaller current can be supplied to the coil device to prevent an increase in the amount of heat generated, and the coil device can be made smaller.Although a flow path is straightly formed in a vertical direction in the related art so that the damping function is greatly reduced when there is a disturbance in the coil device, the orifice plate according to exemplary embodiments in the present invention has a flow path formed annularly so that even when a magnetic field is not applied (as in a hydraulic engine mount using a general hydraulic fluid), when the MR fluid flows, an appropriate viscosity resistance may be induced so as to be able to provide a minimum amount of the damping function.Further, the lower core and the upper core are made of a material having a high relative permeability, and the lower plate and the upper plate are made of a material having a low relative permeability, so that the magnetic field lines (example of force) are concentrated at the flux paths, thus improving the control efficiency.The apparatus in the present invention has other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following Detailed Description, which together serve to explain certain principles of the present invention.Brief Description of the FiguresFIG. 1 is a cross-sectional view of an engine mount into which a conventional hydraulic fluid is filled. FIG. 2 is a view illustrating a related art orifice plate structure installed in a hydraulic engine mount in which MR fluid is filled, and showing the arrangement states of the particles in the MR fluid depending on whether or not a magnetic field is applied. FIG. 3 is a perspective view and a partially enlarged cross-sectional view showing the internal shape of an orifice plate according to an exemplary embodiment of the present invention. FIG. 4 is an exploded view illustrating the orifice plate of FIG. 3. FIG. 5 is a view showing the orifice plate of FIG. 3 upside down (for example), and is an exploded view of the orifice plate turned upside down. FIG. 6 is views illustrating the orifice plate of FIG. 3 cut in different regions to illustrate the cross-sectional view of each region. FIG. 7 is a view illustrating the assembling order of an orifice plate according to an exemplary embodiment of the present invention. FIG. 8 is an elevational view (e.g., phantom view) illustrating the inside of an orifice plate according to another exemplary embodiment of the present invention.It is to be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of the various features illustrative of the basic principles of the invention. The specific structural features of the present invention as disclosed herein, including, for example, specific dimensions (e.g., dimensions), orientations, locations, and shapes will be determined in part by the particular intended application and use environment.In the figures, reference numerals refer to the same or equivalent parts of the present invention throughout the several figures.DETAILED DESCRIPTIONReference will now be made in detail to the various embodiments of the present invention, examples of which are illustrated in the accompanying drawings and described below. Although the invention will be described in connection with exemplary embodiments, it is to be understood that the present description is not intended to limit the invention to these exemplary embodiments. On the contrary, the invention is intended to cover not only the exemplary embodiments, but also various alternatives, modifications, variations and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims.Hereinafter, an orifice plate for an engine (for example, an internal combustion engine, hereinafter also referred to as an engine) mount in which an MR fluid is filled according to an exemplary embodiment of the present invention will be described in detail with reference to the drawings.An orifice plate according to an exemplary embodiment of the present invention includes a core device that houses (e.g., encloses, e.g., houses, e.g., houses) the coil device, is formed in a disc-like shape, and defines a flow path of which an upper passage is disposed in an upper surface of the core device and a lower passage is disposed in a lower surface of the core device. As illustrated in FIG. 3, the core device is formed of a lower plate 10, a lower core 20, an upper core 30, and an upper plate 50 coupled to each other, and a coil device 40 is installed between the lower core 20 and the upper core 30.The flux path forms annular inner and outer flux paths along the inner and outer peripheries of the core means 40, respectively, to increase the effective area of the above-mentioned magnetic field by means of the total flux path (e.g., the total length of the flux path). Further, in order to allow the MR fluid to circulate through the flow path in only one direction, flow path separators (e.g., separators, e.g., dividers) 60 and 70 are installed between the upper passage and the lower passage.Referring to FIGS. 4 and 5, the lower plate 10 is formed in a circular plate shape and has a protrusion portion 11 formed at a center thereof, and the lower passages 12 aand 12 bof the inner flow path and the outer flow path are formed therein at respective predetermined positions. A bolt hole 11 ais defined in the protrusion portion 11 so that a bolt can be fastened and coupled by the protrusion portion 11 and an opening 51 of the upper plate 50.The lower core 20 mounted above the lower plate 10 is formed in a circular plate shape and defines a passage opening 25 at a position communicating with the lower passage 12 bof the outer flow path. An opening 24 having a predetermined inner diameter is formed in the center of the lower core 20 so that the lower passage 12 aof the inner flow path is exposed at a predetermined distance from the protrusion portion 11. In order to form the inner flux path and the outer flux path and to form a predetermined space 23 in which the coil means 40 is to be accommodated, an inner edge (e.g., ridge) 22 having a predetermined height (to contact the inner periphery of the coil means) is formed and protrudes along the periphery of the opening 24, and an outer edge (e.g., ridge) 21 protrudes upward along a periphery to the outside thereof (of the lower core 20).The upper core 30 mounted above the lower core 20 is formed in a circular plate shape and defines a passage opening 35 communicating with an upper passage 52 aof the inner flow path, defines an opening 34 at its center into which the protrusion portion 11 is inserted (for example, can be inserted), and has an inner edge (for example, land) 32 protruding downward along the circumference of the opening 34. The inner rim 32 has a predetermined outer diameter so that it can be disposed to the inside of a lower passage 12 of the inner flow path. An outer edge (e.g., web) 31 projects downwardly along an outer periphery of the upper core 30. accordingly, a predetermined space 33 defines an inner flux path and an outer flux path between the inner edge 32 and the outer edge 31, and the coil means is received therein (e.g., in the space 33).The upper plate 50 installed above the upper core 30 has a circular plate shape and defines upper passages 52 aand 52 bof the inner flow path and the outer flow path.A first flow path separator 60 for partially blocking the inner flow path is mounted on the inside of the central opening 24 of the lower core 20 to contact the protrusion portion 11 (see FIGS. 5 and 7 ), and a second flow path separator 70 for partially blocking the outer flow path is mounted on the inside of the outer edge 21 of the lower core 20 to contact the upper core 30.As illustrated in FIG. 6, in order to move the MR fluid over the longest possible distance (so as to be influenced by the magnetic field as much as possible), the upper passages 52 aand 52 bof the inner flow path and the outer flow path, respectively, and the lower passages 12 aand 12 bare disposed adjacently to each other with a predetermined distance therebetween, and the first flow path separator 60 and the second flow path separator 70 are disposed therebetween, respectively. Thereby, the MR fluid flowing into the inner flow path or the outer flow path is blocked at the first flow path separator 60 or the second flow path separator 70, and circulates in a direction along the circumference of the coil device.The coil device 40 is configured with a coil cover coupled to a coil wound in a ring shape so that the MR fluid does not directly contact the coils, and is wired to receive electricity (for example, current) from the outside. In order for the coil assembly 40 not to warp (e.g., not wave) and be secured within the coil assembly, the coil assembly 40 is tightly (e.g., taut) secured on both sides between the inner edge 22 of the lower core 20 and the outer edge 31 of the upper core 30.In order for the magnetic field lines of a magnetic field to be concentrated, the lower core 20 and the upper core 30 may be made of a material having a high relative permeability, and the lower plate 10 and the upper plate 50, and the first flow path separator 60 and the second flow path separator 70 may be made of a material having a low relative permeability.Referring to FIG. 7, in order to expose the lower passage 12 aof the inner flow path above the lower plate 10 after the lower core 20 is installed, the first flow path separator 60 is installed at a side of the lower passage 20. The first flow path separator 60 is installed to be disposed between the upper passage 52 aand the lower passage 12 aof the inner flow path. The coil device 40 is seated on the second flow path separator, and the second flow path separator 70 is installed at a side of the lower passage 12 bof the outer flow path. The second flow path separator 70 is installed to be disposed between the upper passage 52 band the lower passage 12 bof the outer flow path. The upper core 30 and the upper plate 50 are sequentially installed to form an inner flux path to the inside of the coil device 40 and an outer flux path to the outside of the coil device 40.Alternatively, according to an exemplary embodiment of the present invention, as illustrated in FIG. 8, two or more flow path separators may be installed in the inner flow path or the outer flow path. In this case, an upper passage and a lower passage may be additionally formed depending on the number of the flow path separators. That is, in order to allow the MR fluid to circulate only a half revolution along the circumference of the coil device, a first flow path separator 60 aand a second flow path separator 70 aare additionally installed on the opposite side, and in order to discharge the MR fluid prevented from flowing by the additionally installed flow path separators 60 aand 70 ato the outside, lower passages 12 cand 12 dand upper passages 52 cand 52 dmay be additionally installed in the lower plate 10 and the upper plate 50. Portions of such flow paths may be formed according to the characteristics of the MR fluid (e.g., viscosity, particle density, etc.). That is, when the viscosity of the MR fluid is excessively high as compared with that of a hydraulic fluid of the related art so that the flow rate is low (lower than a preset standard value), the flow paths may be partitioned to prevent a reduction in characteristics even when no current is applied to the coil device 40. In this case, although the effective area affected by a magnetic field may be reduced, the control efficiency may be compensated by adjusting the diameter of the upper passage or the lower passage or by other types of adjustment.For convenience in explanation and accurate definition in the appended claims, the terms "upper", "lower", "inner" and "outer" are used to describe features of the exemplary embodiments with reference to the positions of such features as displayed in the figures.The foregoing description of specific exemplary embodiments of the present invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed, and many modifications and variations may, of course, be made in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical embodiment, to thereby enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the appended claims and their equivalents.

Claims

An orifice plate device for an engine mount filled with a magnetorheological fluid, the orifice plate device comprising a coil device (40) having a coil wound thereon and having an annular shape, a core device unit (20, 30) enclosing the coil device (40) and formed in a disc-like shape and defining a flow path, an upper passage (52a) thereof being disposed in an upper surface of the core device unit (20, 30) and a lower passage (12a) thereof being disposed in a bottom surface of the core device unit (20, 30), the flow path being annularly formed around the periphery of the coil device (40), and a flow path separator (60), This is because the upper passage (52a) and the lower passage (12a) are installed between each other so as to allow unidirectional circulation of the magnetorheological fluid passing through the flow path.The orifice plate apparatus according to claim 1, wherein the flow path includes at least two flow paths formed at two locations within the core device unit (20, 30) and which are fluid-separated from each other, the at least two flow paths including: an inner flow path formed at an inner portion of the coil device (40) and an outer flow path formed at an outer portion of the coil device (40), wherein first (60) and second (70) flow path separators are installed adjacent to the inner flow path and the outer flow path, respectively, to change a flow direction of the magnetorheological fluid.The orifice plate apparatus according to claim 2, wherein the core device unit comprises: a lower plate (10) having a circular plate shape and having a protrusion portion (11) formed in a center thereof, and first and second lower passages (12a, 12b) corresponding to the inner and outer flow paths; a lower core (20) having a circular plate shape and installed above the lower plate (10) and having a first passage orifice (25) formed therein and communicating with the second lower passage (12b) of the outer flow path; and a first orifice (24) formed in a center thereof, wherein an inner edge (22) is formed protruding upward along an inner periphery of the first orifice (20), and wherein an outer edge (21) is formed, said upper core protruding upward along an outer periphery of said lower core (20), and an upper core (30) having a circular plate shape and installed above said lower core (20) and having a second passage opening (35) formed therein and a second opening (34) formed in a center thereof, wherein an inner edge (32) protruding downward is formed along an inner periphery of said second opening (34), and wherein an outer edge (31) protruding downward is formed along an outer periphery of said upper core (30) such that said protruding portion is coupled to said inner edge (32) of said second opening (34), said second passage opening (35) being in fluid communication with said first lower passage (12a) through a first space, A core device formed between the inner edge (22) of the lower core (20) and the inner edge (32) of the upper core (30), wherein the first passage opening (25) is in fluid communication with a second space formed between the outer edge (31) of the upper core (30) and the outer edge (21) of the lower core (20), and wherein the core device is disposed between the lower core (20) and the upper core (30), and an upper plate (50) having a circular plate shape and installed above the upper core (30) and having first and second upper passages (52a, 52b) of the inner flow path and the outer flow path, wherein the second passage opening (35) of the upper core (30) is in fluid communication with the first upper passage (52a) and the second space is in fluid communication with the second upper passage (52b).The orifice plate device according to claim 3, wherein the first flow path separator (60) is disposed in the first space between the first lower passage (12a) and the second passage orifice (35).The orifice plate device according to claim 3, wherein the second flow path separator (70) is disposed in the second space between the first passage orifice (25) and the second upper passage (52b).The orifice plate apparatus according to claim 3, wherein the coil means (40) is installed between the inner edge (22) of the lower core (20) and the outer edge (31) of the upper core (30).The orifice plate device according to claim 3, wherein the lower core (20) and the upper core (30) are made of a material having a higher relative permeability than the lower plate (10) and the upper plate (50).The orifice plate device according to claim 2, wherein two or more flow path separators are installed in the inner flow path or outer flow path to prevent the fluid communication therebetween, and wherein an upper passage and a lower passage are additionally formed according to the number of the flow path separators.An orifice plate device for an engine mount filled with a magnetorheological fluid, the orifice plate device comprising a coil device (40) having a coil wound thereon and having an annular shape, a core device unit (20, 30) accommodating the coil device (40) and formed in a disc-like shape and defining at least two flow paths, wherein at least two upper passages (52a, 52b) are formed in an upper surface of the core device unit, and at least two lower passages (12a, 12b) are arranged in a bottom surface of the core device unit, the at least two flow paths being annularly formed around a periphery of the coil device (40), and wherein the at least two flow paths are formed at two locations within the core device unit and are fluid separated from each other, the at least two flow paths comprising an inner flow path formed at an inner portion of the coil device (40) and an outer flow path formed at an outer portion of the coil device (40), wherein a first (60) and a second (70) flow path separator are installed between the upper passage (52a, 52b) and the lower passage (12a, 12b) adjacent to the inner flow path and the outer flow path, respectively, to change a flow direction of the magnetorheological fluid into a unidirectional flow along the circumference of the coil device (40).The orifice plate apparatus according to claim 9, wherein the core device unit comprises: a lower plate (10) having a circular plate shape and having a protrusion portion (11) formed in a center thereof, and first and second lower passages (12a, 12b) corresponding to the inner and outer flow paths; a lower core (20) having a circular plate shape and installed above the lower plate (10) and having a first passage orifice (25) formed therein and communicating with the second lower passage (12b) of the outer flow path and a first orifice (24) formed in a center thereof, an inner edge (22) being formed protruding upward along an inner periphery of the first orifice (24), and an outer edge (21) being formed, said upper core protruding upward along an outer periphery of said lower core (20), and an upper core (30) having a circular plate shape and installed above said lower core (20) and having a second passage opening (35) formed therein and a second opening (34) formed in a center thereof, wherein an inner edge (32) protruding downward is formed along an inner periphery of said second opening (34), and wherein an outer edge (31) protruding downward is formed along an outer periphery of said upper core (30) such that said protruding portion is coupled to said inner edge (32) of said second opening (34), said second passage opening (35) being in fluid communication with said first lower passage (12a) through a first space, A core device formed between the inner edge (22) of the lower core (20) and the inner edge (32) of the upper core (30), wherein the first passage opening (25) is in fluid communication with a second space formed between the outer edge (31) of the upper core (30) and the outer edge (21) of the lower core (20), and wherein the core device is disposed between the lower core (20) and the upper core (30), and an upper plate (50) having a circular plate shape and installed above the upper core (30) and having first and second upper passages (52a, 52b) of the inner flow path and the outer flow path, wherein the second passage opening (35) of the upper core (30) is in fluid communication with the first upper passage (52a) and the second space is in fluid communication with the second upper passage (52b).The orifice plate device according to claim 10, wherein the first flow path separator (60) is disposed in the first space between the first lower passage (12a) and the second passage orifice (35).The orifice plate device according to claim 10, wherein the second flow path separator (70) is disposed in the second space between the first passage orifice (25) and the second upper passage (52b).The orifice plate apparatus according to claim 10, wherein the coil means (40) is installed between the inner edge (22) of the lower core (20) and the outer edge (31) of the upper core (30).The orifice plate device according to claim 10, wherein the lower core (20) and the upper core (30) are made of a material having a higher relative permeability than the lower plate (10) and the upper plate (50).The orifice plate device according to claim 9, wherein two or more flow path separators are installed in the inner flow path or the outer flow path to prevent the fluid communication therebetween, and wherein an upper passage and a lower passage are additionally formed according to the number of the flow path separators.

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