JP5330345B2 - Washing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a washing machine including a suspension capable of reducing the amount of a magnetic viscous fluid used, preventing the leakage of the magnetic viscous fluid from a storage part, and maintaining desired damping force for a long period. <P>SOLUTION: The washing machine includes a suspension for supporting in a vibration-isolated manner a water tub having a rotatable washing tub disposed therein. The suspension includes: a coil spring provided between a housing and the water tub so as to be connected thereto in a vertical direction; a cylinder unit; and a shaft reciprocating in the cylinder unit. The cylinder unit includes: a magnetic field generator disposed in a tubular cylinder so as to form a space around the shaft; and sealing members disposed so as to seal the upper and lower ends of the space and form a hollow storage part. A magnetic viscous fluid which changes its viscosity when a magnetic field is applied thereto by the magnetic field generator, and gas are enclosed in the storage part. <P>COPYRIGHT: (C)2012,JPO&amp;INPIT

Description

  Embodiments of the present invention relate to a washing machine in which a water tank is supported by a suspension by vibration isolation.

  Conventionally, for example, in a drum-type washing machine, a water tub provided with a rotatable drum is elastically supported by a plurality of suspensions at the bottom of a housing, and exhibits a damping function that reduces vibration associated with the rotation of the drum. I am doing so. By the way, as an example of a suspension, for example, a suspension using a magnetorheological fluid (MR fluid) whose viscosity changes depending on the strength of a magnetic field is known (for example, see Patent Document 1).

  Since the above-mentioned magnetorheological fluid can variably control the viscosity of the fluid by applying a magnetic field, the adoption of the magnetorheological fluid as a suspension for a washing machine has recently been studied. For example, by contacting the magnetorheological fluid with a shaft that moves up and down (reciprocating) with the vibration of the water tank, and by functioning as a resistance (frictional force) that suppresses the vertical movement of the shaft by its viscosity, Therefore, it is intended to provide a washing machine with low vibration and low noise.

  Such a suspension is configured so as to fill a hollow accommodating portion sealed with a magnetorheological fluid and to make frictional contact with a shaft that moves up and down. Therefore, in order to obtain the desired damping performance even in long-term use, the magnetorheological fluid does not leak out from the accommodating portion and does not decrease, and the sealing member for sealing is required to be solid and highly accurate. . Moreover, since the magnetorheological fluid is expensive, the amount used is preferably as small as possible.

However, the temperature of the magnetorheological fluid may increase under use conditions or the like, and in this case, so-called thermal expansion in which the volume increases. For this reason, the magnetorheological fluid accommodated in the full state may leak out of the accommodating portion against the sealing performance of the sealing member. As a result, the capacity of the magnetorheological fluid is reduced, and as a result, the viscosity change of the magnetorheological fluid becomes unstable and cannot be controlled accurately, and there is a concern that a desired damping force cannot be obtained as a suspension.

JP 2006-57766 A

  Accordingly, a washing machine including a suspension that can reduce the amount of use of the magnetorheological fluid, can be prevented from leaking out of the housing portion, and can maintain a desired damping force for a long period of time is provided.

According to the washing machine of the present embodiment, there is a suspension for supporting the vibration of a water tub having a rotatable washing tub inside, and the suspension is provided by being vertically connected between a housing and the water tub. A coil spring, a cylinder device, and a shaft that reciprocates in the cylinder device. The cylinder device is disposed in a cylindrical cylinder so as to form a gap around the shaft, and to form a hollow accommodating portion by sealing the upper and lower ends of the gap. A sealed member. From the stroke of the shaft, which encloses a magnetorheological fluid whose viscosity changes when a magnetic field is applied by the magnetic field generator and gas , and reciprocates based on the vibration of the water tank during dehydration operation. The axial distance between the gas in the housing and the shaft is set small .

1 is a partially enlarged longitudinal sectional view showing a first embodiment of a suspension Longitudinal cross section of suspension unit Longitudinal sectional view showing the outline of the overall structure of the washing machine applied to the drum type washing machine FIG. 1 equivalent diagram showing the second embodiment

(First embodiment)
Hereinafter, a first embodiment applied to a drum type washing machine will be described with reference to FIGS. 1 to 3. First, a drum-type washing machine (hereinafter simply referred to as a washing machine) shown in FIG. 3 is a washing machine with a drying function, and its entire structure will be described. A laundry doorway 2 is formed at a substantially central portion of the front surface (right side in the drawing) of the box-shaped housing 1 forming the outer shell, and a door 3 for opening and closing the doorway 2 is provided. Further, an operation panel 4 is provided at the upper part of the front surface of the housing 1, and a control device 5 for operation control is provided on the back side.

  A water tank 6 is disposed inside the housing 1. The aquarium 6 has a horizontal cylindrical shape with the axial direction as front and rear, and a pair of left and right suspensions 7 (only one is shown) having a longitudinal direction on the bottom plate 1a of the housing 1 (details will be described later). It is elastically supported in an upwardly inclined state.

  A motor 8 is attached to the back surface of the water tank 6. The motor 8 is composed of, for example, a direct current brushless motor, and is an outer rotor type. A rotating shaft (not shown) attached to the central portion of the rotor 8a is inserted into the water tank 6 through the bearing bracket 9, It connects with the center part of the back part of drum 10 mentioned below.

  The drum 10 is disposed inside the water tub 6 and functions as a washing tub for storing laundry. The drum 10 has a horizontal cylindrical shape whose front and rear are axial directions, and is connected to the rotating shaft of the motor 8 as described above. The water tank 6 is supported in a tilted state that is coaxial with the front-up. As a result, the drum 10 is directly driven by the motor 8 and rotates around the horizontal axis, and the motor 8 functions as a drum driving device that rotates the drum 10.

  In addition, a large number of small holes 11 through which water can be passed and ventilated are formed in the peripheral side portion (body portion) of the drum 10 over the entire area. On the other hand, the water tank 6 has a substantially non-porous shape and can store water. Yes. Both the drum 10 and the water tub 6 have openings 12 and 13 on the front surface, and an annular bellows 14 is mounted between the opening 13 of the water tub 6 and the laundry entrance 2. ing. Thereby, the laundry entrance 2 is configured to be connected to the inside of the drum 10 via the bellows 14, the opening 13 of the water tub 6, and the opening 12 of the drum 10. A drain pipe 16 is connected to the lowest part of the water tank 6 capable of storing water via a drain valve 15 on the way so that the water can be drained outside the apparatus.

  Here, the configuration of the above-described drying function will be described. The drying unit 17 is provided from the back side of the water tank 6 to the upper side and the front side. The drying unit 17 is composed of a blower 19, a heating device 20, and a circulation duct 18 provided with a dehumidifying means (not shown). The drying unit 17 dehumidifies moisture in the air discharged from the water tank 6 during the drying operation, and then heats it. Then, a so-called dry air is generated and circulated repeatedly to be returned to the water tub 6 to dry the laundry in the drum 10 driven to rotate.

  The specific structure of the suspension 7 will be described with reference to FIGS. As shown in FIG. 3, the suspension 7 is provided between the housing 1 and the water tank 6 in the vertical direction as a schematic configuration. Specifically, the suspension 7 is a mounting plate 21 included in the bottom plate 1 a of the housing 1. A cylindrical cylinder device 30 attached to the side, a shaft 24 which is inserted in the cylinder device 30 so as to be movable up and down, and whose upper end portion is attached to the attachment plate 23 side of the water tank 6, and the shaft 24 and the cylinder device 30 The coil spring 25 is mounted between them.

  In this way, as a specific structure for mounting the suspension 7 in the casing 1, as shown in FIG. 2, the cylinder connecting portion 30a is attached to the lower end portion of the cylinder device 30, and the connecting portion 30a is connected to the lower end portion of FIG. The cylinder device 30 is attached and fixed to the attachment plate 21 on the bottom plate 1a side by fastening with a nut 27 via an elastic seat plate 26 such as rubber to the attachment plate 21 of the bottom plate 1a shown in FIG. Although a specific configuration of the cylinder device 30 will be described later, the cylinder device 30 includes an iron cylindrical cylinder 22 that forms an appearance, a magnetic field generator 40 disposed in the cylinder 22, and the like.

  On the other hand, the shaft 24 includes a shaft main portion 24a inserted into the cylinder device 30 and a shaft connecting portion 24b integrally connected to an upper end portion thereof. At least the shaft main portion 24a is made of iron. It is a magnetic material. Thus, the connecting portion 24b is fastened to the mounting plate 23 of the water tank 6 with a nut 29 via a similar elastic seat plate 28 or the like, so that the shaft 24 follows the vibration of the water tank 6 and is integrally moved in the vertical direction. The connection structure vibrates in the same manner.

  The details of the mounting structure of the coil spring 25 will be described later with reference to FIG. 1 and will be described later. In this case, the lower end is supported by the upper end of the cylinder device 30 and the upper end is disposed above the shaft 24. It is received in the shape of the spring receiving portion 49 and is mounted in a state where the elastic force is accumulated. That is, the shaft 24 is stretched so as to be urged so as to be pulled out from the cylinder device 30 upward.

  Here, a specific configuration of the cylinder device 30 will be described with reference to FIGS. 1 and 2. First, a brief description will be given. The shaft 24 is linearly reciprocated (vertically moved) in the cylinder 22. The bearing means for pivotally supporting it is arranged and fixed so as to be spaced apart from the upper and lower parts. In addition, the magnetic field generator 40, the magnetorheological fluid (both will be described in detail later) and the like are accommodated in an intermediate portion sandwiched between the lower bearing means.

  Therefore, the specific structure of the lower bearing means will be described with reference to FIG. 2. The lower bearing holding member 31, which is in the shape of an annular hollow cylinder, is accommodated in the cylinder 22. It is fixed. The bearing holding member 31 is made of, for example, a nonmagnetic material made of aluminum, and a groove portion 32 extending in the circumferential direction is formed on the outer peripheral portion thereof. A portion corresponding to the groove portion 32 in the peripheral wall portion of the cylinder 22 is formed. The bearing holding member 31 is fixed in the cylinder 22 by caulking so as to protrude inward.

  An annular bearing 33 that directly supports the shaft 24 so as to reciprocate in the up-down direction, which is also the axial direction, is fitted and fixed to the hollow inner peripheral portion of the bearing holding member 31. The bearing 33 functions as a sliding bearing that is in sliding contact with the shaft 24 and is composed of a copper-based sintered oil-impregnated bearing that is a nonmagnetic material in the present embodiment. In addition, the bearing holding member 31 not only holds the bearing 33 but also press-fits one sealing member 38c, which will be described in detail later, on its upper surface side, and functions as the sealing member holding member. Yes. A stop ring 34 is attached to the lower end portion of the shaft 24, and the ring 34 abuts on the lower surface of the bearing holding member 31, thereby restricting the upward movement of the shaft 24.

  On the other hand, a specific configuration on the upper bearing means side will be described with reference to an enlarged sectional view of FIG. 1 in particular, and an upper bearing holding member 35 having an annular hollow cylindrical shape inside the upper end portion of the cylinder 22. Is housed and fixed. The bearing holding member 35 is made of an aluminum non-magnetic material like the lower bearing holding member 31, and a groove portion 36 is formed over the entire periphery of the outer peripheral lower portion, and the groove portion of the peripheral wall portion of the cylinder 22 is formed. The bearing holding member 35 is fixed to the upper end portion of the cylinder 22 by, for example, rolling caulking so as to project the portion corresponding to 36 inward. An elastic O-ring 37 is attached to the groove portion 36, and the O-ring 37 is sandwiched by caulking of the cylinder 22 with respect to the groove portion 35 of the bearing holding member 35 and is held in close contact, and is securely fixed. In addition, a waterproof structure is provided to prevent water from entering the cylinder 22.

  The upper bearing holding member 35 fits and holds the bearing 39 at an intermediate position in the vertical direction inside the hollow interior, and press-fits and holds, for example, two sealing members 38a and 38b in the inner lower portion. It also functions as a sealing member holding member. In addition, the outer peripheral side portion of the bearing holding member 35 also functions as a spring holding member that holds the coil spring 25 (details will be described later). The bearing 39 is made of a non-magnetic material composed of a copper-based sintered oil-impregnated bearing, like the lower bearing 33 described above.

  More specifically, the shape of the outer surface of the hollow cylindrical bearing holding member 35 has a cylindrical two-stage shape in which the lower half is large in diameter and the upper half is small in diameter. . The caulking groove portion 36 is formed on the outer surface of the large-diameter cylindrical portion 35a. And the level | step-difference part 35c is formed in the boundary of the small diameter cylinder part 35b and large diameter cylinder part 35a of an upper half part. The step portion 35c supports the lower end portion of the coil spring 25, and the outer surface of the small diameter cylindrical portion 35b is close to the lower end inner diameter side of the coil spring 25 and holds it from the side. The bearing holding member 35 also functions as a spring holding member.

  On the other hand, the internal shape of the bearing holding member 35 has a plurality of stages of hollow shapes having different diameters, and the large-diameter internal portion 35d at the position corresponding to the large-diameter cylindrical portion 35a includes two sealing members 38a. , 38b are arranged in two stages so as to overlap each other and are press-fitted and held. Here, the structure of the sealing members 38a and 38b will be described. As is apparent from FIG. 1, it corresponds to a so-called springless oil seal in which a metal ring is insert-molded in a rubber body having a sealing lip. To do. However, in a general oil seal, the metal ring is usually made of iron, but in this embodiment, it is made of a nonmagnetic material made of aluminum, for example. The sealing members 38a and 38b employ the same oil seal as the sealing member 38c held by the lower bearing holding member 31 and disposed opposite thereto. When the three sealing members 38a, 38b, and 38c are generically described, they are simply referred to as the sealing member 38 for explanation.

  A small-diameter interior 35e that is smaller in diameter than the large-diameter interior 35d is formed continuously, and the cylindrical bearing 39 is press-fitted and held in the small-diameter interior 35e. The small-diameter inside 35e forms an insertion hole 35f that is located at a substantially intermediate position of the bearing holding member 35 and that further reduces the diameter so as to form a stepped portion that also serves to prevent the bearing 39 from coming off upward. The insertion hole 35f is inserted through the shaft 24 so as to reciprocate. Therefore, the shaft 24 constitutes a bearing means, is pivotally supported by the bearings 39 and 33 of the lower bearing holding members 35 and 31, and is provided so as to be capable of reciprocating in a state of being in watertight sliding contact with the sealing member 38. It is done.

  The specific configuration of the magnetic field generator 40 provided between the upper and lower bearing means will be described. The magnetic field generator 40 is basically wound around the shaft 24 and generates a magnetic field (magnetic field). The coil 41 has a structure including an iron-made cylindrical yoke 42 provided on the upper and lower portions of the coil 41. When the coil 41 is energized, the upper and lower yokes surround the coil 41. The magnetic circuit A through which the magnetic flux passes through 42 is formed.

  In the following, in detail, in the present embodiment, as shown in FIGS. 1 and 2, the magnetic field generator 40 includes coils 41 arranged in two upper and lower stages, each wound around a hollow cylindrical bobbin 43, and the bobbin A cylindrical gap is formed between the outer peripheral surface of the shaft 24 inserted through the hollow portion at the center of 43. More specifically, the bobbin 43 is composed of bobbins 43a and 43b disposed on the lower side and having substantially the same configuration, and an upper coil 41a is wound around the upper bobbin 43a. The yoke 42a is arranged in the upper part, and the yoke 42b is arranged in the middle part corresponding to the lower part.

  The lower coil 41b side has substantially the same configuration as described above, and the lower coil 41b is wound around the lower bobbin 43b, the intermediate yoke 42b corresponding to the upper part is located, and the lower yoke 42c is provided at the lower part. (Only FIG. 2 is shown). The coils 41 a and 41 b are connected in series, and the hollow portion of the cylindrical yoke 42 (generally referred to simply as the yoke 42) is also narrowed between the outer peripheral surface of the shaft 24. A cylindrical gap extending in the vertical direction is formed in communication with the gap formed by the bobbin 43 (generally referred to simply as the bobbin 43). Is done.

  In this manner, in the state where the yoke 42 is disposed on the upper and lower portions (including intermediate portions) of the coil 41 (generally referred to simply as the coil 41) wound around the bobbin 43, for example, a thermoplastic resin (nylon, PBT) , PET, PP, or the like) and a resin mold (indicated by a resin mold portion 44 in the figure) to form an integrated configuration, and thus the magnetic field generator 40 is configured. Therefore, the magnetic field generation device 40 forms a gap around the shaft 24, and the sealing members 38b and 38c among the sealing members 38 arranged at the upper and lower ends of the magnetic field generation device 40 have the gap. The upper and lower end portions are sealed to form a cylindrical accommodating portion 50. In this case, the uppermost sealing member 38a has a function of preventing the intrusion of water from the upper bearing 39 side while securely sealing the housing portion 50 in a double sealed state.

  In the housing portion 50, a magnetorheological fluid 45 is supplied and housed as particularly shown in FIG. This magnetorheological fluid 45 is a fluid whose viscosity changes by application of electrical energy, and its viscosity characteristics change according to the strength of the magnetic field (magnetic field). For example, in a base oil mainly composed of polyalphaolefin oil. It consists of a dispersion of ferromagnetic particles such as iron and carbonyl iron. When a magnetic field is applied, the ferromagnetic particles form a chain cluster and the apparent viscosity increases.

  The supply of the magnetorheological fluid 45 to the housing part 50 is, as a matter of course, a state in which the magnetic field generator 40 and the upper and lower bearing means are inserted into the shaft 24 to form the housing part 50 including a sealed gap. Injected from an inlet (not shown) and sealed.

  However, in the present embodiment, the magnetorheological fluid 45 is injected in 70 to 80% of the entire accommodating portion 50, and the remaining 20 to 30% is sealed with air 48 (shown in white in the figure). An example will be described with reference to FIG. 1. The effective area X, which is the entire length in the vertical direction of the housing portion 50, corresponds to the axial length of the outer peripheral surface of the shaft 24 facing the housing portion 50. . In other words, it corresponds to the axial length of the outer peripheral surface of the shaft 24 that can come into contact with the fully accommodated magnetorheological fluid 45, and has a dimension corresponding to the gap between the lips of the sealing members 38b and 38c facing the upper and lower portions. is there.

  Accordingly, in the present embodiment, the fluid region that contains the magnetorheological fluid 45 is denoted by reference numeral X1 and the gas region that accommodates the air 48 located in the upper layer portion is denoted by reference symbol X2 with respect to the effective region X of the entire housing portion 50. Show. That is, it can be said that the gas region X <b> 2 corresponds to an axial distance in which the shaft 48 contacts with the air 48 that is a gas in the housing portion 50.

  The gas region X2 of this axial length is set to be smaller than the stroke S of the shaft 24 that moves up and down based on the vibration of the water tank 6 that occurs in the initial stage of the dehydration operation (X2 <S). In the dehydration operation, as is well known, the drum 10 rotates at a high speed. However, centrifugal dehydration is performed by passing through the resonance rotation speed and reaching a predetermined high rotation speed at the initial driving stage. In the vicinity of the resonance rotational speed, the vibration of the drum 10 becomes large and overcomes this to reach normal high-speed rotation. Therefore, in order to obtain a damping action by the suspension 7 before the vibration becomes large, if the stroke S of the shaft 24 due to the vibration at the time of dehydration activation is 10 mm, the gas region X2 is set to 10 mm or less. Although details will be described later in the description of the operation, the yoke 42 a located in the uppermost portion of the magnetic field generator 40 in the stationary state illustrated in FIG. 1 has an arrangement configuration corresponding to the gas region X 2 in contact with the air 48. Show.

  As described above, the accommodating portion 50 is originally formed from a narrow gap so that a small amount of the magnetorheological fluid 45 can be accommodated. However, according to the present embodiment, the lower layer portion of the accommodating portion 50 has a magnetorheological fluid due to gravity. 45 is accommodated, and the upper layer portion has a two-layer configuration in which air 48 is accommodated. Therefore, the amount of the magnetorheological fluid 45 to be used is further reduced, and in this case, the amount corresponding to the amount of air 48 is reduced. It will be.

  Thereafter, these constituent members are inserted into the cylinder 22. In a state in which the members are inserted to a predetermined position, the members 22 and 35 formed in the bearing holding members 31 and 35 are caulked so as to project the cylinder 22 inward, thereby fixing these members integrally. Thus, the cylinder device 30 is configured. A hollow portion 30b that is closed by a connecting member 30a is formed in the lower portion of the cylinder device 30 to secure a space that allows the shaft 24 to move downward.

  The cylinder device 30 is assembled as a suspension 7 by incorporating a coil spring 25. First, the lower end portion of the coil spring 25 is supported on the step portion 35 c of the upper bearing holding member 35 that is the upper end portion of the cylinder device 30. Next, the connecting member 24b is connected to the shaft main portion 24a so that the upper end portion of the coil spring 25 is received by a disk-shaped spring receiving portion 49 provided at the upper end portion of the shaft main portion 24a. In this case, the coil spring 25 is mounted in a state where it is slightly compressed and the elastic force is accumulated.

  In the suspension 7 configured as described above, the shaft 24 and the coil spring 25 are located on the water tank 6 side in the vertical direction between the bottom plate 1a of the housing 1 and the water tank 6 as described above, as shown in FIG. With the cylinder device 30 positioned on the housing 1 side, the water tank 6 is disposed on both the left and right sides and elastically connected and supported. Further, the two lead wires 46 drawn from the upper and lower coils 41 a and 41 b are drawn using the yoke 42 b portion of the intermediate portion and led out to the outside through a bush 47 attached to the cylinder 22. Then, it is connected to the control device 5 through a drive circuit (not shown), so that the power interruption control to the coil 41 of the magnetic field generation device 40 can be performed.

  Note that broken line arrows A1 and A2 shown in FIG. 1 indicate magnetic circuits generated around the coils 41a and 41b when the coils 41a and 41b are energized, and indicate the flow direction of the magnetic field. Accordingly, the magnetic circuit A will be simply referred to as a magnetic circuit A for explanation. That is, the magnetic circuit A1 generated on the upper coil 41a side extends from the shaft 24 → the housing 50 (gap) → the upper yoke 42a → the cylinder 22 → the intermediate yoke 42b → the housing 50 (gap) → the shaft 24. It is formed by a route.

  Similarly, the magnetic circuit A2 on the coil 41b side on the lower stage side extends from the shaft 24 → the housing portion 50 (gap) → the lower yoke 42c → the cylinder 22 → the intermediate yoke 42b → the housing portion 50 (gap) → the shaft 24. It is formed by a route. Thus, each member of the shaft 24, the yoke 42, and the cylinder 22 constituting the magnetic circuit A is formed of an iron magnetic material.

Next, the operation of the washing machine having the above configuration will be described.
In the washing machine equipped with the drum 10 around the horizontal axis of the present embodiment, the controller 5 is operated by driving and controlling the drum 10 at an appropriate rotation speed in each of the washing, rinsing, dewatering, and drying processes. Is executed. When the drum 10 vibrates due to an unbalanced load caused by the laundry accommodated in the drum 10, the elastically supported water tank 6 also vibrates mainly in the vertical direction. In response to the vertical vibration of the water tank 6, the suspension 7 expands and contracts a coil spring 25 between the shaft 24 integrally connected to the water tank 6 and the cylinder device 30, and the shaft 24 moves inside the cylinder device 30. Vibrates vertically (reciprocates). The coil spring 25 has a function of absorbing vibration by its expansion and contraction action and effectively preventing vibration transmission to the housing 1 (bottom plate 1a) side.

  On the other hand, the magnetorheological fluid 45 and the sealing member 38 are in sliding contact with the shaft 24 moving up and down, and exert an effect of quickly damping vibration by the frictional force. That is, the magnetorheological fluid 45 supplied into the accommodating portion 50 functions as a frictional resistance against the reciprocating motion of the shaft 24 in the vertical direction due to its viscosity, and acts to attenuate the vibration amplitude of the water tank 6.

  Further, the sealing member 38 includes two sealing members 38 a and 38 b on the upper side of the magnetic field generator 40 and one sealing member 38 c on the lower side, and each sealing lip has an outer periphery of the shaft 24. Since the surface slides in a watertight manner and a considerable frictional force is obtained, this effectively functions as a damping action. The damping action by the sealing member 38 is always generated as a minimum frictional force and functions effectively as an auxiliary damping action.

  In addition, when the drum 10 is driven to rotate, the coil 41 constituting the magnetic field generator 40 is energized to generate a magnetic field. As a result, the magnetic circuits A1 and A2 are formed around the coils 41a and 41b arranged in the upper and lower two stages, and the gap is also narrowed between the yoke 42 and the shaft 24 having a particularly high magnetic flux density. In combination, the viscosity of the magnetorheological fluid 45 to which a magnetic field is applied in the gap portion is rapidly increased, increasing the frictional resistance against the reciprocating motion of the shaft 24 in the vertical direction. As a result, the vibration of the water tank 6 is increased. Attenuates the amplitude quickly.

  Since the coil 41 is provided with two coils 41a and 41b in the upper and lower stages, the yokes 42a, 42b, 42b, and 42c disposed on the upper and lower portions of the coils 41a and 41b based on the magnetic circuits A1 and A2, respectively. A magnetic field can be applied to the magnetorheological fluid 45 at a total of four positions between the shafts 24, and the change in viscosity of the magnetorheological fluid 45 can be increased quickly, so that a desired damping force can be obtained instantaneously and current control can be performed accordingly. Is easy and reliable.

  However, in this embodiment, in order to reduce the amount of the magnetorheological fluid 45, the accommodating portion 50 has a two-layer configuration in which the magnetorheological fluid 45 is accommodated in the lower layer portion by gravity and air 48 as gas is enclosed in the upper layer portion. . Therefore, when the uppermost yoke 42a is disposed in the gas region X2 where the magnetorheological fluid 45 does not exist as disclosed in FIG. 1, a magnetic field cannot be applied to the magnetorheological fluid 45 at that portion. For this reason, the risk that the damping force using the magnetorheological fluid 45 is reduced can be considered.

  However, the suspension 7 is not in a stationary state that maintains the above state, but can exhibit a damping action as follows. That is, the vibration generated in the water tank 6 is directly transmitted to the shaft 24 and reciprocates in the cylinder device 30 in the vertical direction. Among them, the magnetorheological fluid 45 having a viscosity according to the upward movement in particular is pulled up in a state where it partially adheres to the surface of the shaft 24. In this case, the magnetorheological fluid 45 existing mainly in the gap between the upper bobbins 43a is pulled up in a state of adhering to the shaft 24, and reaches the gap where the uppermost yoke 42a is positioned while the vertical movement is repeated. .

  As described above, the gas region X2 has the stroke S of the shaft 24 that moves up and down based on the vibration at the start of the dehydration operation that rotates the drum 10 at high speed, that is, the vibration of the water tank 6 at the start before reaching the resonance rotational speed. Since it is set to be smaller (X2 <S), the shaft 24 can move beyond the gas region X2 after the dehydration operation is started, and the shaft 24 can contact the magnetorheological fluid 45 in a wide axial range. It becomes. As a result, due to repeated vertical movement of the shaft 24, a part of the magnet viscous fluid 45 reaches the position of the uppermost yoke 42a due to the viscosity of the magnet viscous fluid 45, and the magnet viscous fluid 45 is inserted into the narrow gap between the yoke 42a and the shaft 24. Can be obtained.

  Therefore, the portion of the shaft 24 that was initially in contact with the air 48 (corresponding to the gas region X2) also comes into contact with the magnetorheological fluid 45 to generate a frictional force, thereby exhibiting the action of quickly damping the vibration of the water tank 6. As described above, in order to reduce the amount of the magnetorheological fluid 45 in the housing portion 50, even a configuration in which a part of the air 48 is enclosed can be put to practical use. In order to make the above action more reliable, the magnetorheological fluid 45 in the present embodiment has a characteristic that it is easy to adhere to the shaft 24 by adding an additive for increasing the viscosity to the base oil and does not easily dissociate.

  Moreover, since the magnetorheological fluid 45 can reach the position of the uppermost yoke 42a as described above, the coil 41 of the magnetic field generator 40 is energized especially in the dehydration operation in which the drum 10 is rotated at a high speed. Although the magnetic circuit A is formed, a magnetic field can be applied by using the magnetorheological fluid 45 pulled up on the side of the uppermost yoke 42a that generates the upper magnetic circuit A1. Accordingly, it is possible to expect a damping action substantially the same as the state in which the magnetorheological fluid 45 is fully accommodated in the accommodating portion 50 from the beginning.

  In addition to the energization control in accordance with the above dehydration operation as the control means for the magnetorheological fluid 45, control for energizing the coil 41 immediately before reaching the rotational speed near the resonance point associated with the high speed rotation of the drum 10 (including current value) Variable control) or by providing vibration detection means in the water tank 6 and controlling energization according to the detection result.

  In addition, during the dehydrating operation, a large abnormal vibration that cannot be suppressed by the suspension 7 may occur due to the unbalanced arrangement of the laundry. Normally, in this type of washing machine, initial abnormal vibration can be detected as a safety measure, and the control device 5 stops the temporary dehydration operation in response to the detection signal, and executes the unbalance correction process that is to be restarted. I have to. For this reason, the dehydration drive may be repeatedly performed depending on the case, and the energization time becomes longer because the coil 41 is energized continuously. In this case, when the energization time becomes longer, the temperature of the coil 41 rises to, for example, about 100 ° C., and the magnetorheological fluid 45 located inside the coil 41 also rises in temperature through the peripheral member.

  This temperature rise causes a volume increase of the magnetorheological fluid 45 and shows a phenomenon of thermal expansion upward. However, in the present embodiment, since the air 48 is accommodated in the upper layer portion, the air layer enjoys the change due to the thermal expansion. At this time, if the magnetorheological fluid 45 is accommodated in the entire accommodating portion 50 as in the prior art, part of the thermally expanded magnetorheological fluid 45 may leak from the upper sealing member 38b. In the case of leakage, the concentration (amount) of the magnetorheological fluid 45 in the housing part 50 changes, and the intended damping action cannot be obtained. Furthermore, when the leaked magnetorheological fluid 45 enters the sliding contact portion between the shaft 24 and the sealing member 38 or the bearing 39, there is a concern that the wear of these members is accelerated and the original function is not performed. In contrast, in the present embodiment, these problems do not occur, and the suspension 7 having excellent durability can be configured.

  In this embodiment, the upper and lower bearing holding members 35 and 31 and the bearing holding members 35 and 31 are members adjacent to the shaft 24 and the yoke 42 which are members constituting the magnetic circuit A. Since the sealing member 38, the bearings 39, 33, and the like are made of a non-magnetic material, the magnetic field from the magnetic circuit A can be prevented from leaking through these adjacent members, and efficient control is possible and stable damping force. Is obtained.

  As described above, according to the washing machine of the first embodiment, the upper and lower end portions of the gap formed around the shaft 24 in the cylinder device 30 in the suspension 7 that supports the vibration isolation of the water tub 6 by the sealing member 38. The container 50 is sealed to form a hollow housing part 50. In this housing part 50, a magnetorheological fluid 45 whose viscosity changes when a magnetic field is applied by energization, and a gas 48 are enclosed in the upper layer part of the magnetorheological fluid 45. I tried to do it.

  With the above configuration, the amount of the expensive magnetorheological fluid 45 used can be reduced, and cost reduction can be expected. Further, there is a risk that the frictional contact between the shaft 24 and the magnetorheological fluid 45 may be reduced in the upper layer portion of the accommodating portion 50 by reducing the amount, but in this embodiment, the water tank at the start of the dehydrating operation for rotating the drum 10 at a high speed. The axial distance (gas region X2) where the shaft 24 comes into contact with the air 48, which is a gas in the accommodating portion 50, is set small with respect to the stroke S of the shaft 24 that moves up and down based on the vibration of the shaft 6. Can move up and down beyond the range in which the fluid is in contact with the magnetorheological fluid 45 located on the lower layer side, and even if the magnetorheological fluid 45 is reduced, the above-described damping action can be promoted.

  Further, since the upper layer portion is an air layer, the uppermost yoke 42a is often arranged to face the air 48. However, the magnet viscous fluid 45 is moved in accordance with the vertical movement of the shaft 24 due to the viscosity of the magnet viscous fluid 45. Can be pulled up to the position of the upper yoke 42a, so that a magnetic field can be applied through the upwardly moving magnetoviscous fluid 45, and attenuation control using the viscosity change of the magnetorheological fluid 45 becomes possible. In particular, in this embodiment, since the viscosity is increased by adding an additive to the base oil of the magnetorheological fluid 45, it has a characteristic that it easily adheres to the shaft 24 and does not easily peel off, and follows the movement of the shaft 24. It is suitable for.

  In addition, since air 48 is sealed in the upper layer as a gas, the magnetorheological fluid 45 can be injected while a predetermined amount of air 48 is left at the time of manufacture, and the injection work is more easily performed in conjunction with the reduction of the amount. it can. Moreover, the volume reduction of the magnetorheological fluid 45 and the encapsulation of the air 48 in the upper layer expand, for example, when the temperature of the magnetorheological fluid 45 rises. It has an advantage that the magnetorheological fluid 45 can be prevented from leaking out of the sealed region.

  This can maintain a predetermined capacity of the magnetorheological fluid 45, and a stable damping action can be expected over a long period of time. In particular, when the container 50 is filled with the magnetorheological fluid 45, it is easy to leak, and when leaked, it enters between the adjacent member such as the peripheral bearing means and the shaft 24 and wears out. Although various problems are recalled, according to the present embodiment, such an unexpected situation is not caused, and it is very effective for practical use.

It should be noted that the present invention is not limited to the above-described embodiment, and the following modifications can be made in connection with the configuration in which the air 48 is sealed in the upper layer portion of the accommodating portion 50.
First, an antioxidant is added to the base oil constituting the magnetorheological fluid 45. According to this, the magnetorheological fluid 45, which tends to increase in temperature based on the energization control, may be oxidized because the hot base oil and the air 48 may come into contact with each other, but this may be prevented. That is, it is possible to provide the magnetorheological fluid 45 that can prevent deterioration due to oxidation of the base oil and can maintain desired characteristics over a long period of time.

  Further, the yokes 42 arranged on the upper and lower portions of the coil 41 constituting the magnetic field generator 40 are made of iron-based sintered metal. As a result, the yoke 42 can be impregnated with the magnetorheological fluid 45, and a good magnetic circuit A can always be generated. In this case, the yoke 42 is preferably impregnated with the magnetorheological fluid 45 in advance.

  Or it is good also as a structure which uses only the uppermost yoke 42a as a ferrous sintered metal. This is because the air 48 occupies the upper layer portion of the accommodating portion 50, so that the magnetorheological fluid 45 is often not interposed only in the gap portion between the uppermost yoke 42 a and the shaft 24. As the vibration of the water tank 6 is generated, the shaft 24 moves up and down to gradually pull the lower magnetorheological fluid 45 to a position corresponding to the yoke 42a. At that time, the yoke 42a lowers the magnetorheological fluid 45. By impregnating, an action such as filling the narrow gap with the magnetorheological fluid 45, that is, replenishing the magnetorheological fluid 45 can be expected, and an effective magnetic circuit A1 can be formed quickly.

  In addition, the sealing member 38 mainly serves to prevent leakage of the magnetorheological fluid 45 in order to form the accommodating portion 50. In addition, frictional resistance (damping force) obtained in a fixed manner with the shaft 24, and further an upper bearing The specifications may be made in consideration of preventing water from entering from the 39 side. Therefore, the sealing member 38 may have a sealing lip with an oil seal configuration with a spring, and the holding member of the sealing member 38 is not limited to the configuration also used as a bearing holding member, and a dedicated holding member is provided. Various modifications are possible including the installation location and the number, such as a configuration.

(Second Embodiment)
FIG. 4 is a view corresponding to FIG. 1 showing the second embodiment. Hereinafter, the same parts as those in the above embodiment are denoted by the same reference numerals, description thereof will be omitted, and different points will be described in detail.

  In this configuration, the magnetic viscous fluid 45 is further reduced, and the volume of the accommodating portion 50 is reduced by inserting a cylindrical spacer 51 between the bobbin 43 and the shaft 24 (gap). It is a thing. As a result, it is possible to reduce the volume corresponding to the volume occupied by the spacers 51a and 51b provided at two upper and lower positions. However, in this embodiment, it is needless to say that the amount is reduced by the amount occupied by the air 48 on the upper spacer 51a side.

  The spacer 51 is preferably larger in diameter than the shaft 24 so as not to prevent the vertical movement of the shaft 24 and to maintain the contact state between the shaft 24 and the magnetic viscous fluid 45. Furthermore, the spacer 51 may have an endless cylindrical shape, or may have an end-cylinder shape having a straight cut in the vertical (vertical) direction.

  In the above-described embodiment, the present invention is applied to a drum-type washing machine having a drum around the horizontal axis. However, the present invention is not limited to this. For example, a laundry tub that also serves as a dewatering tub that can rotate around the vertical axis is provided. However, the present invention can also be applied to a so-called vertical axis type washing machine provided with a bottomed cylindrical water tank on the vertical axis.

In addition, the shaft is connected to the water tank side, and the inside of the cylinder device is moved up and down (reciprocating). However, the present invention is not limited to this, for example, the cylinder side is attached to the water tank side, It is good also as a connection structure to attach. In this case, the cylinder side directly reciprocates in response to the water tank, but the shaft is configured to reciprocate relative to the cylinder, and substantially the same effect as the above embodiment can be expected.
In addition, although two coils constituting the magnetic field generator are provided and arranged in two upper and lower stages, for example, a single coil configuration may be used, and various modifications can be made specifically.

  As mentioned above, although some embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  In the drawings, 1 is a housing, 6 is a water tub, 7 is a suspension, 10 is a drum (washing tub), 22 is a cylinder, 24 is a shaft, 25 is a coil spring, 31 and 35 are bearing holding members (sealing member holding members) ), 33, 39 are bearings, 38 (38a, 38b, 38c) are sealing members, 40 is a magnetic field generator, 41 (41a, 41b) is a coil, 42 (42a, 42b, 42c) is a yoke, and 45 is magnetic. Viscous fluid, 48 is air (gas), 50 is an accommodating portion, and 51 (51a, 51b) is a spacer.

Claims (7)

In a suspension that supports vibration isolation of a water tub having a wash tub that can rotate inside,
The suspension includes a coil spring connected in a vertical direction between a housing and the water tank, a cylinder device, and a shaft that reciprocates in the cylinder device,
The cylinder device is disposed in a cylindrical cylinder so as to form a gap around the shaft, and to form a hollow accommodating portion by sealing the upper and lower ends of the gap. And having a sealed member,
From the stroke of the shaft, which encloses a magnetorheological fluid whose viscosity changes when a magnetic field is applied by the magnetic field generator and gas , and reciprocates based on the vibration of the water tank during dehydration operation. The washing machine is characterized in that the axial distance between the shaft and the gas in the housing is set small .   The washing machine according to claim 1, wherein the gas sealed in the housing is air constituting an upper layer of the magnetorheological fluid.   The washing machine according to claim 1 or 2, wherein an antioxidant is added to the base oil constituting the magnetorheological fluid. The magnetic viscous fluid, a washing machine according to claim 1, wherein the set in viscosity to adhere to the shaft. Magnetic field generator includes a coil that is wound around the shaft, has a yoke disposed at upper and lower portions of the coil, according to claim 1, wherein said yoke is characterized in that a sintered metal iron Washing machine. 6. The washing machine according to claim 5 , wherein the yoke located at the top of the magnetic field generator is made of iron-based sintered metal . Washing machine according to claim 1, wherein the in the gap portion was arranged a spacer to reduce the volume of the housing portion excluding the yoke housing part.

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