Damper and washing machine comprising same

Abstract

A damper and a washing machine according to the present invention are characterized by comprising: a case having an accommodation space therein; a coil unit that is accommodated in the case, generates a magnetic field, and includes a rod hole; a rod which is installed by being passed through the case, and of which a portion is positioned in the rod hole and another portion is positioned outside the case; and a fluid that is accommodated in the rod hole and changes in viscosity in response to a change in the magnetic field generated by the coil unit.

Description

Damper and washing machine including same

[0001] The present disclosure relates to a damper, and more particularly, to a damper that provides damping force corresponding to various conditions.

[0002] In a conventional washing machine (patent document 1), a tub is installed inside an outer case forming the exterior with a friction damper and a buffer spring as a medium, and a drum capable of holding laundry is accommodated inside this tub. In addition, this drum is installed at the bottom and is installed to be rotatable with a motor and a belt installed to rotate according to the power supply by a power cord.

[0003] That is, when the motor rotates, the belt rotates synchronously and transmits rotational power to a pulley fixed to the rotational axis of the drum, so that the rotational power of the motor is transmitted to the drum.

[0004] Therefore, after power is supplied to the above motor and the control unit is operated to enter the dehydration cycle of the drum washing machine, the motor, which is the driving source, begins to rotate and rotates the drum installed in the tub via a belt.

[0005] At this time, the tub vibrates up, down, left, and right due to the centrifugal force acting on it due to the unbalanced mass generated by the laundry inside the drum.

[0006] That is, the motion applied to the above tub is transmitted to the lower part of the outer case and is damped by the friction damper installed at the lower part.

[0007] However, since the conventional friction damper only provides a constant damping force, when centrifugal force is generated due to the unbalanced mass during dehydration, a large vibration occurs in the transient state where the vibration of the tub passes the natural frequency, and even when the steady-state rotation speed is reached, vibration displacement occurs due to eccentricity, but the friction damper has a problem in that the characteristics of the damper do not change according to these conditions, resulting in a large vibration.

[0008] Patent Document 2 describes a friction damper. Specifically, the damper (70) is configured to include a piston mechanism (80) connected to the drum-side damper bracket (61), a cylinder mechanism (90) connected to the base-side damper bracket (62), a friction member (74) fixed to one of the piston mechanism (80) and the cylinder mechanism (90) to generate friction due to relative motion, and an elastic member (76) providing elasticity to the piston mechanism (80).

[0009] In the case of Patent Document 2, there is also a problem in that the damper provides constant friction and elasticity, and thus the transient vibration of the tub cannot be effectively attenuated.

[0010] [Prior Art Literature]

[0011] [Patent Document]

[0012] Patent Document 1 - Korean Publication No. 2006-0120918

[0013] Patent Document 2 - Korean Publication No. 2005-0043171

[0014]

[0015] The problem to be solved by the present disclosure is to provide a damper capable of simultaneously reducing transient and steady-state vibrations by changing the damping value by varying the characteristics of a magnetorheological fluid according to a change in a magnetic field, and a washing machine including the same.

[0016] The problem to be solved by the present disclosure is to provide a damper and a washing machine including the damper, which has a very high yield stress, is resistant to impurities, and is current-controlled, and thus does not require a high-voltage device.

[0017] The problem to be solved by the present disclosure is to provide a damper having a simple structure, easy to manufacture, and low manufacturing cost, and a washing machine including the damper.

[0018] The tasks of the present disclosure are not limited to the tasks mentioned above, and other tasks not mentioned will be clearly understood by those skilled in the art from the description below.

[0019]

[0020] The damper according to the present disclosure for solving the above-described problem is characterized in that it adjusts the damping force by changing the magnetic field applied to the fluid contained inside the case.

[0021] Specifically, a damper according to the present disclosure is characterized by including a case having an accommodation space therein, a coil unit accommodated inside the case, generating a magnetic field and including a rod hole, a rod installed penetrating the case, a portion of which is positioned inside the rod hole and another portion of which is positioned outside the case, and a fluid accommodated in the rod hole, the viscosity of which changes according to a change in the magnetic field generated in the coil unit.

[0022] A fluid gap in which the fluid is positioned can be defined between the coil unit and the load.

[0023] The coil unit may include a first ferromagnetic body, a second ferromagnetic body, a third ferromagnetic body positioned between the first ferromagnetic body and the second ferromagnetic body, a first coil portion positioned between the first ferromagnetic body and the third ferromagnetic body, and a second coil portion positioned between the second ferromagnetic body and the third ferromagnetic body.

[0024] The first coil section may include an inner cover having a load hole therein, a coil arranged to surround the inner cover, and an outer cover arranged to surround the coil.

[0025] The inner cover and the outer cover may include resin.

[0026] The inner cover may comprise aluminum.

[0027] The first ferromagnetic body, the second ferromagnetic body, and the third ferromagnetic body may include steel.

[0028] Additionally, the present disclosure may further include a coil housing accommodated in the accommodation space and arranged to surround the coil unit.

[0029] The above coil housing may have a cylindrical shape surrounding the first direction.

[0030] The above coil housing may comprise steel.

[0031] The case may include a mid-case arranged to surround the coil unit, an upper case coupled to the upper end of the mid-case and including an upper through-hole through which the load passes, and a lower case coupled to the lower end of the mid-case.

[0032] In addition, the present disclosure further includes an arm connected to one end of the lower case, and a load space for accommodating a portion of the load may be formed inside the arm.

[0033] The above lower case may further include a lower through hole through which the load passes.

[0034] The above load may further include a load recessed portion that is recessed inward from the outer surface of the load.

[0035] The above load depressions can be arranged in multiple numbers spaced apart in the first direction.

[0036] The above load depression may have a ring shape when viewed in the first direction.

[0037] In addition, according to one embodiment of the present disclosure, a washing machine includes a casing, a tub installed inside the casing and containing washing water therein, a drum rotatably installed inside the tub, and a damper supporting the tub within the casing and providing a damping force, wherein the damper includes a case having a receiving space therein, a coil unit received inside the case, generating a magnetic field, and including a rod hole, a rod installed penetrating the case, a part of which is located inside the rod hole and the other part of which is located outside the case, and a fluid received in the rod hole, the viscosity of which changes according to a change in the magnetic field generated from the coil unit.

[0038] The above load of the above damper can be fastened to the above tub, and one end of the above case of the above damper can be fastened to the above casing.

[0039] In addition, the present disclosure further includes an elastic member supporting the tub to the casing, the elastic member being positioned above the rotational center of the drum, and the damper being positioned below the rotational center of the drum.

[0040] The coil unit may include a first ferromagnetic body, a second ferromagnetic body, a third ferromagnetic body positioned between the first ferromagnetic body and the second ferromagnetic body, a first coil portion positioned between the first ferromagnetic body and the third ferromagnetic body, and a second coil portion positioned between the second ferromagnetic body and the third ferromagnetic body.

[0041] The damper and washing machine of the present disclosure have one or more of the following effects.

[0042] First, the present disclosure has the advantage of simultaneously reducing transient and steady-state vibrations by changing the damping value by varying the characteristics of the magnetorheological fluid according to the change in the magnetic field.

[0043] Second, the present disclosure can provide a large damping force because it can greatly increase the viscosity of the magnetorheological fluid by supplying a small amount of current, resulting in a very large yield stress, and it has the advantage of being resistant to impurities because foreign substances from outside cannot easily enter the interior of the case.

[0044] Third, the present disclosure has the advantage of reducing the total length of the damper while improving the damping force of the damper by making the length of the rod longer than the length of the case, since a portion of the load is accommodated in the accommodation space of the arm.

[0045] Fourth, the present disclosure has the advantage of easily increasing the contact area between the load and the fluid by stacking ring-shaped coil assemblies without using a separate spring, thereby easily increasing the damping force.

[0046] Fifth, the present disclosure has a simple structure in which a ring-shaped coil unit is inserted into a cylindrical case and a load is inserted inside the coil unit, so that it is easy to manufacture and has a low manufacturing cost, and a large facing area can be secured between the load and the coil unit, so that the damping force of the damper can be greatly improved.

[0047] Sixth, the present disclosure has the advantage that the coil of the coil portion includes an inner cover and an outer cover, so that the coil is protected and the coil can be easily aligned during assembly.

[0048] Seventh, the present disclosure has the advantage of evenly distributing a magnetic field and inducing a large viscosity in a fluid with a small current by axially separating two coil sections and placing a ferromagnetic material between them.

[0049]

[0050] FIG. 1 is a side cross-sectional view illustrating the internal configuration of a washing machine according to one embodiment of the present disclosure.

[0051] FIG. 2 is a cross-sectional view illustrating the internal configuration of a washing machine according to one embodiment of the present disclosure.

[0052] FIG. 3 is a perspective view of a damper according to one embodiment of the present disclosure.

[0053] Figure 4 is an exploded perspective view of the damper illustrated in Figure 3.

[0054] Fig. 5 is a cross-sectional view taken along the axial direction of the damper illustrated in Fig. 3.

[0055] FIG. 6 is an exploded perspective view of a coil unit according to one embodiment of the present disclosure.

[0056] Fig. 7 is an exploded perspective view of the coil section illustrated in Fig. 6.

[0057] FIG. 8 is a diagram illustrating a magnetic field distribution of a coil unit according to one embodiment of the present disclosure.

[0058] FIG. 9 is a cross-sectional view of another damper according to another embodiment of the present disclosure.

[0059] Fig. 10 is a cross-sectional view of the load illustrated in Fig. 9.

[0060] Fig. 11 is a control flowchart of a damper according to one embodiment of the present disclosure.

[0061] Fig. 12 is a graph showing a current control process according to the rotation speed of a washing machine according to one embodiment of the present disclosure.

[0062]

[0063] The advantages and features of the present disclosure, and methods for achieving them, will become clearer with reference to the embodiments described in detail below together with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below and may be implemented in various different forms. These embodiments are provided solely to ensure that the disclosure of the present disclosure is complete and to fully inform those skilled in the art of the scope of the invention, and the present disclosure is defined only by the scope of the claims. Like reference numerals designate like elements throughout the specification.

[0064] Spatially relative terms such as "below," "beneath," "lower," "above," and "upper" can be used to easily describe the relationship between one component and another, as illustrated in the drawings. Spatially relative terms should be understood to include different orientations of the components during use or operation in addition to the orientations depicted in the drawings. For example, if a component depicted in the drawings were flipped over, a component described as "below" or "beneath" another component could be positioned "above" the other component. Thus, the exemplary term "below" can include both the above and below orientations. Components can also be oriented in other directions, and thus spatially relative terms can be interpreted based on their orientation.

[0065] The terminology used herein is for the purpose of describing embodiments only and is not intended to be limiting of the present disclosure. As used herein, the singular includes the plural unless specifically stated otherwise. As used herein, the terms "comprises" and / or "comprising" do not exclude the presence or addition of one or more other components, steps, and / or operations.

[0066] Unless otherwise defined, all terms (including technical and scientific terms) used herein may be used in their common sense to those of ordinary skill in the art to which this disclosure pertains. Furthermore, terms defined in commonly used dictionaries are not to be interpreted ideally or excessively unless explicitly and specifically defined otherwise.

[0067] The thickness and size of each component in the drawings are exaggerated, omitted, or schematically illustrated for convenience and clarity. Furthermore, the size and area of ​​each component do not entirely reflect its actual size or area.

[0068] Additionally, the angles and directions mentioned in the process of describing the structure of the embodiment are based on those described in the drawings. If the reference points and positional relationships for angles are not clearly mentioned in the description of the structure forming the embodiment in the specification, the relevant drawings should be referenced.

[0069] The present disclosure will be described in detail with reference to the attached drawings.

[0070] FIG. 1 is a side cross-sectional view illustrating the internal configuration of a washing machine according to one embodiment of the present disclosure, and FIG. 2 is a front cross-sectional view illustrating the internal configuration of a washing machine according to one embodiment of the present disclosure.

[0071] Referring to FIGS. 1 and 2, in one embodiment of the present disclosure, a washing machine comprises a casing (2) forming the exterior of the washing machine, a tub (6) installed on the inside of the casing (2) by an elastic member (4) and a damper (100) and containing washing water therein, a drum (8) rotatably installed on the inside of the tub (6) and having a plurality of holes (7) formed therein for loading laundry and allowing washing water to flow in and out, a lifter (10) installed on the inner surface of the drum (8) to lift laundry loaded into the drum (8) and then drop it from a certain height, and a motor (12) installed on the rear side of the tub (6) to transmit power to the drum (8).

[0072] Here, the casing (2) includes a cabinet (22) forming the side and back of the washing machine, a base (24) forming the bottom of the washing machine, a top plate (26) coupled to the top of the cabinet (22) to form the upper surface of the washing machine, and a cabinet cover (28) mounted on the front of the cabinet (22) to form the front of the washing machine.

[0073] A control panel (14) that controls the operation of the washing machine or displays it to the user is placed between the cabinet cover (28) and the top plate (26), and a door (18) that opens and closes the laundry entrance (27) is rotatably installed on the front of the cabinet cover (28).

[0074] And, the upper part of the tub (6) is installed on the upper part of the cabinet (22) by a plurality of elastic members (4), and the lower part is supported so as to be cushioned on the upper surface of the base (24) by a plurality of dampers (100).

[0075] That is, the elastic member (4) is composed of a left elastic member (4A) whose lower end is connected to the upper left side of the tub (6) and whose upper end is connected to the upper left side of the cabinet (2), and a right elastic member (4B) whose lower end is connected to the upper right side of the tub (6) and whose upper end is connected to the upper right side of the cabinet (2).

[0076] Cabinet brackets (30) having upper hanging holes (31) for hanging the upper part of elastic members (5) are installed on the upper left and right sides of the cabinet (22), respectively, and spring connecting parts (32) having lower hanging holes (33) for hanging the lower part of elastic members (5) are formed on the upper left and right sides of the tub (6), respectively.

[0077] As the elastic member (4), a coil (140) spring having a certain elastic coefficient is used.

[0078] In addition, the damper (100) is composed of a left damper (100) (100A) whose upper end is connected to the lower left side of the tub (6) and whose lower end is connected to the upper left side of the base (24), and a right damper (100) (100B) whose upper end is connected to the lower right side of the tub (6) and whose lower end is connected to the upper right side of the base (24).

[0079] The damper (100) is connected to the damper connection portions (34) formed on the lower side of the tub (6) and the upper side of the base (24) by a damper pin (40). The damper connection portions (34) are formed on the lower left and right sides of the tub (6) and are composed of an upper damper connection portion (36) to which the upper side of the damper (100) is connected by a damper pin (40), and a lower damper connection portion (38) to which the lower side of the damper (100) is connected by a damper pin (40) and are formed on the upper left and right sides of the base (24).

[0080] The elastic member (4) may be positioned above the rotation center of the drum (8), and the damper (100) may be positioned below the rotation center of the drum (8).

[0081]

[0082] Hereinafter, the damper (100) of the present disclosure will be described in detail.

[0083] FIG. 3 is a perspective view of a damper according to an embodiment of the present disclosure, FIG. 4 is an exploded perspective view of the damper illustrated in FIG. 3, and FIG. 5 is a cross-sectional view of the damper illustrated in FIG. 3 taken along the axial direction.

[0084] Referring to FIGS. 3 to 5, a damper (100) according to one embodiment of the present disclosure includes a case (110), a rod (120), a coil unit (140), and a fluid (190).

[0085] The case (110) has an internal accommodation space (A). The accommodation space (A) accommodates a fluid (190), a coil unit (140), and a portion of a rod (120). Here, the fluid (190) accommodated in the accommodation space (A) may include a magnetorheological fluid whose properties change due to a magnetic field generated in the coil unit (140).

[0086] The magnetorheological fluid changes its viscosity according to changes in the magnetic field generated in the coil unit (140), thereby changing the frictional force between the fluid (190) and the rod (120) and the frictional force between the fluid (190) and the coil unit (140).

[0087] For example, a magnetorheological fluid is a dispersion of magnetic particles in a solvent.

[0088] The rod (120) is installed through the case (110), and the rod (120) can move relative to the case (110). That is, the rod (120) can reciprocate along the axial direction (Ax) in the case (110). Here, with reference to FIG. 3, the upper side in the axial direction is defined as the upper direction, and the lower side in the axial direction is defined as the lower direction.

[0089] The case (110) may be manufactured in one piece, but may be manufactured in multiple pieces for ease of assembly.

[0090] For example, the case (110) may include a mid case (111), an upper case (112), and a lower case (115). Of course, depending on the embodiment, the mid case (111) and the lower case (115) may be manufactured as one piece.

[0091] The mid-case (111) may have an axially enclosing structure. For example, the mid-case (111) may have a cylindrical shape with both ends in the axial direction (Ax) open and centered on the axis. That is, the mid-case (111) may have a cylindrical shape that is open in the vertical direction.

[0092] The upper case (112) is coupled to the upper end of the mid case (111) and closes the opening at the upper end of the mid case (111). The upper case (112) may include an upper through hole (112a) through which a rod (120) passes.

[0093] An upper sealing portion (161) may be installed in the upper case (112) to prevent fluid (190) from leaking out to the outside by a rod (120) passing through the upper through hole (112a). The upper sealing portion (161) may perform a function of scraping off fluid (190) stuck to the rod (120) like a scraper and a function of preventing fluid (190) inside the case (110) from being discharged to the outside.

[0094] For example, the upper case (112) may further include a hook (113) that is fitted to the upper portion of the mid case (111). The hook (113) is fitted to the upper portion of the mid case (111), and the mid case (111) and the upper case are bonded. When the hook (113) is fitted to the upper portion of the mid case (111), and the mid case (111) and the upper case are bonded, there is an advantage in that no separate screw is required.

[0095] The lower case (115) is coupled to the lower end of the mid case (111) and closes the opening at the lower end of the mid case (111). The lower case (115) may completely close the lower opening of the mid case (111), or the lower case (115) may be formed with a lower through hole (115a) through which the rod (120) passes.

[0096] When the lower penetration hole (115a) is formed and the rod (120) passes through it, the area of ​​the rod (120) that rubs against the fluid (190) increases, thereby improving the damping force and yield stress of the damper (100).

[0097] A lower sealing portion (162) may be installed in the lower case (115) to prevent fluid (190) from leaking out to the outside by a rod (120) passing through the lower penetration hole (115a). The lower sealing portion (162) may perform a function of scraping off fluid (190) stuck to the rod (120) like a scraper and a function of preventing fluid (190) inside the case (110) from being discharged to the outside.

[0098] The case (110) may further include an arm (118). The arm (118) connects the case (110) and the casing (2) of the washing machine. Specifically, one end of the arm (118) is connected to the case (110), and the other end of the arm (118) is connected to the damper connection part (34). More specifically, the other end of the arm (118) may be connected to the lower damper connection part (38).

[0099] More specifically, the arm (118) is connected to the lower end of the lower case (115), and a pin hole (119) into which a damper pin (40) is inserted can be formed at the lower end of the arm (118).

[0100] A space for a load (120) can be formed inside the arm (118) to accommodate a portion of the load (120). The space for the load (120) can be positioned to overlap the lower through hole (115a) in the axial direction (Ax). The space for the load (120) prevents the load (120) protruding outside the case (110) from being visible from the outside, and reduces the length of the space through which the load (120) protrudes, thereby reducing the overall length of the damper (100).

[0101]

[0102] The load (120) may be installed in the case (110) so as to move relative to the case (110). The load (120) may include an inner portion (123) positioned in the receiving space (A) of the case (110) and an outer portion (122, 125) positioned outside the case (110). While the load (120) reciprocates in the axial direction (Ax), the length of the inner portion (123) and the length of the outer portions (122, 125) may change. The inner portion (123) and the outer portions (122, 125) are based on those illustrated in FIG. 5.

[0103] The rod (120) may have various cross-sectional shapes. For example, the rod (120) may have a circular cross-sectional shape intersecting the axial direction (Ax). The rod (120) extends in the axial direction (Ax) in a cylindrical shape. The mid-case (111) may have a circular cross-sectional shape intersecting the longitudinal direction of the rod (120) and may be formed to surround the inner portion (123).

[0104] A first outer portion (122) of the rod (120) can be coupled to the tub. Specifically, one end of the rod (120) is connected to the tub, and a portion of the rod (120) is accommodated in the accommodation space (A) of the case (110). The rod (120) is connected to the damper connection portion (34). More specifically, the rod (120) can be connected to the upper damper connection portion (36).

[0105] The rod (120) may be formed with a pinhole (121) into which a damper pin (40) is inserted. The pinhole (121) may be formed at the top of the first outer portion (122).

[0106] For example, the load (120) may include a first outer portion (122) at least partially exposed to the upper portion of the case (110), a second outer portion (125) at least partially exposed to the lower portion of the case (110), and an inner portion (123) connecting the first outer portion (122) and the second outer portion (125) and positioned within the receiving space (A) of the case (110). The second outer portion (125) may be received in the space (118a) of the load (120) of the arm (118).

[0107] The coil unit (140) is installed to surround the outer periphery of the inner part (123) of the load (120) and generates a magnetic field by power. The coil unit (140) is housed inside the case.

[0108] Below, the detailed structure of the coil unit (140) is described.

[0109] FIG. 6 is an exploded perspective view of a coil unit (140) according to one embodiment of the present disclosure, and FIG. 7 is an exploded perspective view of the coil portion illustrated in FIG. 6.

[0110] Referring to FIGS. 5 to 7, the coil unit (140) may have a cylindrical shape including a rod hole (147) that accommodates a rod (120). The coil unit (140) may have a multi-layer structure to effectively distribute a magnetic field.

[0111] For example, the coil unit (140) may include a first ferromagnetic body (143), a second ferromagnetic body (145), a third ferromagnetic body (144), a first coil portion (141), and a second coil portion (142).

[0112] The first ferromagnetic material (143) may include steel. Of course, the first ferromagnetic material (143) may also be formed of multiple layers. For example, the first ferromagnetic material (143) may have a ring shape that surrounds the axial direction. The first ferromagnetic material (143) may define a rod hole (143a) that accommodates a portion of the rod (120).

[0113] The second ferromagnetic material (145) may include steel. Of course, the second ferromagnetic material (145) may also be formed of multiple layers. For example, the second ferromagnetic material (145) may have a ring shape that wraps around the axial direction. The second ferromagnetic material (145) may define a rod hole (145a) that accommodates a portion of the rod (120).

[0114] The third ferromagnetic material (144) may include steel. Of course, the third ferromagnetic material (144) may also be formed of multiple layers. For example, the third ferromagnetic material (144) may have a ring shape that wraps around the axial direction. The third ferromagnetic material (144) may define a rod hole (144a) that accommodates a portion of the rod (120).

[0115] The third ferromagnetic body (144) may be positioned between the first ferromagnetic body (143) and the second ferromagnetic body (145). That is, the first ferromagnetic body (143), the second ferromagnetic body (145), and the third ferromagnetic body (144) may be positioned spaced apart from each other along the axial direction.

[0116] The first coil portion (141) may include a coil (1413) made of copper. Of course, the first coil portion (141) may be formed of multiple layers. For example, as illustrated in FIG. 7, the first coil portion (141) may include an inner cover (1411) having a load hole (141a) therein, a coil (1413) arranged to surround the inner cover (1411), and an outer cover (1415) arranged to surround the coil (1413).

[0117] For example, the inner cover (1411) and the outer cover (1415) may include resin. As another example, the inner cover (1411) may include aluminum, and the outer cover (1415) may include resin.

[0118] The first coil section (141) is located between the first ferromagnetic body (143) and the third ferromagnetic body (144).

[0119] The second coil portion (142) may include a coil (1413) made of copper. Of course, the second coil portion (142) may be formed of multiple layers. For example, as illustrated in FIG. 7, the second coil portion (142) may include an inner cover (1411) having a load hole (142a) therein, a coil (1413) arranged to surround the inner cover (1411), and an outer cover (1415) arranged to surround the coil (1413).

[0120] For example, the inner cover (1411) and the outer cover (1415) may include resin. As another example, the inner cover (1411) may include aluminum, and the outer cover (1415) may include resin.

[0121] The second coil section (142) can be positioned between the second ferromagnetic body (145) and the third ferromagnetic body (144).

[0122] The coil of the coil part includes an inner cover (1411) and an outer cover (1415), so that the coil is protected and the coil position can be easily aligned during assembly.

[0123] In addition, by axially separating two coil sections and placing a ferromagnetic material between them, the magnetic field is evenly distributed, and a large viscosity can be induced in the fluid with a small current.

[0124] In addition, the load holes (141a to 145a) of the first ferromagnetic body (143), the second ferromagnetic body (145), the third ferromagnetic body (144), the first coil portion (141) and the second coil portion (142) may be positioned to overlap each other when viewed in the axial direction. The sizes of the load holes (141a to 145a) of the first ferromagnetic body (143), the second ferromagnetic body (145), the third ferromagnetic body (144), the first coil portion (141) and the second coil portion (142) may be the same.

[0125] Therefore, the manufacturing difficulty is very low with a simple structure of inserting a ring-shaped coil unit (140) into a cylindrical case and inserting a rod (120) inside the coil unit (140), and since a large surface area can be secured between the rod (120) and the coil unit (140), there is an advantage in that the damping force of the damper can be greatly improved.

[0126] A fluid gap (G) in which fluid is positioned can be formed between the coil unit (140) and the rod (120). Therefore, it is preferable that the diameter of the rod (120) be smaller than the diameter of the rod hole (147) of the coil unit (140).

[0127] According to one embodiment of the present disclosure, since the coil unit (140) has a multi-layer structure, it may further include a coil housing (150) for accommodating them.

[0128] The coil housing (150) is accommodated in the accommodation space (A) of the case and may be formed to surround the coil unit (140) when viewed in the axial direction. For example, the coil housing (150) may have a cylindrical shape with an axial opening. The coil housing (150) may include steel.

[0129]

[0130] FIG. 8 is a diagram illustrating a magnetic field distribution of a coil unit (140) according to one embodiment of the present disclosure.

[0131] When power is applied to the first coil unit (141) and the second coil unit (142), a magnetic field is generated in the first coil unit (141) and the second coil unit (142). The magnetic field generated in the first coil unit (141) and the second coil unit (142) spreads along the first ferromagnetic body (143), the second ferromagnetic body (145), and the third ferromagnetic body (144), and is concentrated in the fluid gap (G) between the coil unit (140) and the rod (120). The magnetic field concentrated in the fluid gap (G) induces a large viscosity of the fluid, which ultimately greatly increases the dimming force of the damper.

[0132]

[0133] Hereinafter, a damper according to another embodiment of the present disclosure will be described in detail.

[0134] FIG. 9 is a cross-sectional view of a damper according to another embodiment of the present disclosure, and FIG. 10 is a cross-sectional view of a load (120) illustrated in FIG. 9.

[0135] Referring to FIGS. 9 and 10, a damper (100-1) according to another embodiment of the present disclosure differs from the embodiment of FIG. 5 in the shape of the rod (120). Hereinafter, differences from FIG. 5 will be mainly described, and configurations without special descriptions will be considered to be identical to the configuration of the embodiment of FIG. 5.

[0136] A load (120) according to another embodiment of the present disclosure is

[0137] The load (120-1) may further include a load recess (126) positioned further from the case (110) than the outer surface of the load (120-1). The outer surface of the load (120) extends parallel to the axial direction (Ax).

[0138] The load recessed portion (126) is formed in the inner portion (123). The outer diameter of the rod (120) in the portion where the load recessed portion (126) is formed may be smaller than the outer diameter of the inner portion (123) of the rod (120). The outer diameter of the rod (120) in the portion where the load recessed portion (126) is formed may have a size of 90% to 95% of the outer diameter of the inner portion (123) of the rod (120).

[0139] Specifically, the width (W) of the load recessed portion (126) may be greater than the depth (H) of the load recessed portion (126). It is preferable that the width (W) of the load recessed portion (126) be 4 to 10 times greater than the depth (H) of the load recessed portion (126). This is because if the depth of the load recessed portion (126) is too large, the rigidity of the load (120) becomes weak.

[0140] The load depression (126) increases the surface area of ​​the inner portion (123) of the load (120), thereby improving the frictional force between the load (120) and the fluid (190).

[0141] This is because, if the load depression (126) is depressed too deeply, the strength of the load (120) is weakened, and if it is depressed too thinly, the frictional force cannot be improved.

[0142] A plurality of load recessed portions (126) may be arranged spaced apart from each other in the first direction. Specifically, the load recessed portion (126) may include a first load recessed portion (126A) positioned corresponding to the first coil portion (141) and a second load recessed portion (126B) positioned corresponding to the first coil portion (141).

[0143] The width of the first load recessed portion (126A) may be the same as the width of the first coil portion (141), and the width of the second load recessed portion (126B) may be the same as the width of the second coil portion (142).

[0144] The first load recessed portion (126A) may be positioned to overlap the first coil portion (141) in a direction perpendicular to the axial direction, and the second load recessed portion (126B) may be positioned to overlap the second coil portion (142) in a direction perpendicular to the axial direction.

[0145] When the first load depression (126A) is positioned to overlap the first coil portion (141) in a direction perpendicular to the axial direction, and the second load depression (126B) is positioned to overlap the second coil portion (142) in a direction perpendicular to the axial direction, the load depression (126) is formed in an area that is greatly influenced by the magnetic field generated from the coil unit (140). Therefore, a large damping force can be generated with only a small current.

[0146] The shape of the load recessed portion (126) is not limited, but a shape that does not reduce the rigidity of the load (120) is preferred. For example, the load recessed portion (126) may have a rounded shape. The axial (Ax) width (W) of the load recessed portion (126) may be greater than the depth (H) of the load recessed portion (126).

[0147]

[0148] Below, the process of controlling the vibration of the damper (100) is described in detail.

[0149] FIG. 10 is a control flowchart of a damper (100) according to one embodiment of the present disclosure, and FIG. 11 is a graph showing a current control process according to the rotation speed of a washing machine according to one embodiment of the present disclosure.

[0150] Referring to FIG. 10, a control unit (300) that detects the rotational speed of a motor (60) sends a control signal to a power supply (400), and the power supply (400) that receives this control signal controls the amount of current flowing in a coil unit (140) constituting a damper (100) via a cable (160), thereby changing the properties of a fluid (190) contained in a receiving space (A) of a case (110), thereby reducing the overall vibration while reducing the vibration in the initial natural frequency range.

[0151] Also, referring to FIG. 11, the process of controlling the current supplied from the power supply (400) according to the rotational speed of the motor (60) during dehydration by the control unit (300) is composed of a first stage in which the current gradually increases before the natural frequency during initial startup, a second stage in which a constant current is applied to reduce transient vibration occurring between 10 Hz and 30 Hz, a third stage in which the current gradually decreases after passing through the transient vibration region, and a fourth stage in which a small current is applied to reduce steady-state vibration.

[0152] Therefore, unlike the friction damper (100) that has a constant damping value in both the transient and normal states during dehydration, by employing the damper (100) of the present embodiment, vibration in the initial natural frequency range of the washing machine is reduced, and a semi-active control system that can reduce overall vibration is constructed.

[0153]

[0154] Although the embodiments of the present disclosure have been described with reference to the attached drawings, the present disclosure is not limited to the embodiments described above, but can be manufactured in various different forms, and those skilled in the art to which the present disclosure pertains will understand that the present disclosure can be implemented in other specific forms without changing the technical spirit or essential characteristics of the present disclosure. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

[0155]

[0156] [Explanation of symbols]

[0157] 10 - Body 40 - Tub

[0158] 50 - Drum 60 - Motor

[0159] 100 - Damper 110 - Case

[0160] 120 - Rod 140 - Coil Unit

Claims

1. A case having a storage space inside; A coil unit housed inside the case, generating a magnetic field and including a load hole; A rod installed through the case, some of which is positioned within the load hole and others of which are positioned outside the case; and A damper that is accommodated in the above load hole and includes a fluid whose viscosity changes according to a change in the magnetic field generated from the coil unit.

2. In claim 1, A damper in which a fluid gap is defined between the coil unit and the load in which the fluid is positioned.

3. In claim 2, The above coil unit, First ferromagnetic material; Second ferromagnetic material; A third ferromagnetic material positioned between the first ferromagnetic material and the second ferromagnetic material; A first coil portion positioned between the first ferromagnetic body and the third ferromagnetic body; and A damper including a second coil portion positioned between the second ferromagnetic body and the third ferromagnetic body.

4. In claim 3, The above first coil part, Inner cover having a load hole inside; A coil arranged to surround the inner cover; and A damper comprising an outer cover arranged to surround the coil.

5. In claim 1, A damper further comprising a coil housing accommodated in the above-described accommodation space and arranged to surround the coil unit.

6. In claim 5, The above coil housing is a damper having a cylindrical shape that surrounds the first direction.

7. In claim 5, The above coil housing is a damper comprising steel.

8. In claim 1, The above case is, A mid-case arranged to surround the above coil unit; An upper case coupled to the upper end of the mid case and including an upper through hole through which the load passes; and A damper comprising a lower case coupled to the lower end of the above mid case.

9. In claim 8, The above case further includes an arm connected to one end of the lower case, A damper in which a load space is formed inside the above arm to accommodate a portion of the above load.

10. In claim 9, The above lower case is A damper further comprising a lower through hole through which the above load passes.

11. In claim 1, The above load is, A damper further comprising a rod recessed portion recessed inward from the outer surface of the above rod.

12. Casing; A tub installed inside the above casing and containing washing water therein; A drum rotatably installed inside the above tub; and A damper is included that supports the tub within the casing and provides damping force, The above damper, A case having a storage space inside; A coil unit housed inside the case, generating a magnetic field and including a load hole; A rod installed through the case, some of which is positioned within the load hole and others of which are positioned outside the case; and A washing machine containing a fluid that is accommodated in the above load hole and whose viscosity changes according to a change in the magnetic field generated in the coil unit.

13. In claim 12, The above load of the above damper is fastened to the above tub, A washing machine in which one end of the case of the above damper is connected to the above casing.

14. In claim 12, Further comprising an elastic member supporting the above tub to the above casing, The above elastic member is positioned above the center of rotation of the drum, A washing machine wherein the above damper is positioned below the center of rotation of the drum.

15. In claim 13, The above coil unit, First ferromagnetic material; Second ferromagnetic material; A third ferromagnetic material positioned between the first ferromagnetic material and the second ferromagnetic material; A first coil portion positioned between the first ferromagnetic body and the third ferromagnetic body; and A washing machine including a second coil portion positioned between the second ferromagnetic body and the third ferromagnetic body.

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