CROSS REFERENCE TO RELATED APPLICATION

This non-provisional application claims the benefit under 35 U.S.C. § 119(a) to Patent Application No. 10-2018-0113472, filed in the Republic of Korea on Sep. 21, 2018, all of which is hereby expressly incorporated by reference into the present application.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present disclosure relates to a washing machine having a clutch operated by a solenoid.

2. Description of the Related Art

A washing machine that is provided with a clutch that is operated by a solenoid, and that selectively connects or disconnects a laundry shaft to a dehydration shaft, is well known. For example, Korean Patent Laid-Open Publication No. 2003-0023316 (hereinafter, referred to as “related art”), as shown inFIGS. 1 to 5, discloses a structure in which a slider94serration-coupled with a dehydration shaft93is separated from a driving container92formed in a rotor91of a washing motor while being lifted by the magnetic force of a solenoid95.

In the state where power is not applied to the solenoid95, the slider94is engaged with both the dehydration shaft93and the driving container92, so that the rotational force of the rotor91is transmitted to the dehydration shaft93through the slider94. At this time, the washing shaft96and the dehydration shaft93are rotated together.

On the contrary, when power is applied to the solenoid95, the slider94is lifted up by the magnetic force of the solenoid95and separated from the driving container92. Therefore, since the rotational force of the rotor91is no longer transmitted to the dehydration shaft93, only the washing shaft96connected to the rotor91is rotated.

The solenoid95is disposed in a space surrounded by first and second yoke plates97and98. At this time, in the second yoke plate98, a flat portion982bent at the lower end of a cylindrical portion981surrounds the bottom surface of the solenoid95.

In the slider94, a movable yoke94aof metallic material receives force upward due to the magnetic force of the solenoid95. At this time, a coupling body94bserration-coupled with the dehydration shaft96in the movable yoke94ais raised along the dehydration shaft96together with the movable yoke94a.

The movable yoke94ais configured to include a cylindrical portion941disposed in an inner area of the solenoid95, and a flange943that is extended from the lower end of the cylindrical portion941, and has an unevenness portion942engaged with an unevenness formed in the driving container92.

A problem of such a related art is magnetic leakage from the movable yoke94ato the washing shaft96.FIG. 5shows the magnetic field generated by the solenoid95. When the first yoke plate97and the second yoke plate98are formed of ferromagnetic material, the first yoke plate97, the second yoke plate98, and the movable yoke94aform a magnetic path in a substantially closed form to concentrate the magnetic flux, and magnetic flux flowing along the magnetic path contributes to lift the movable yoke94a. InFIG. 5, the magnetic path is indicated by a two-point chain line.

However, since the magnetic flux P leaked to the dehydration shaft96from the cylindrical portion941of the movable yoke94asubstantially contributes little to lift the movable yoke94a, such a magnetic loss becomes a factor that reduces the efficiency of the solenoid95.

In addition to this, since the related art uses the first yoke plate97and the second yoke plate98to form the magnetic path, there is a problem in that the number of parts increases, thereby increasing the manufacturing cost.

SUMMARY OF THE INVENTION

The present disclosure has been made in view of the above problems, and provides a washing machine that has a clutch operated by a solenoid, and in particular, a washing machine that forms a fixing core magnetized by the solenoid in a bearing housing in which a bearing is accommodated for supporting a dehydration shaft.

The present disclosure further provides a washing machine which can efficiently use the magnetic flux that contributes to the lifting of the clutch, by improving the magnetic path where the magnetic flux generated from the solenoid moves.

The present disclosure further provides a washing machine in which a separate fixing core added to construct the magnetic path is eliminated, by allowing a bearing housing for accommodating a bearing supporting the dehydration shaft to constitute a part of the magnetic path through which the magnetic flux generated from the solenoid passes.

The present disclosure further provides a washing machine in which a separate part used to install the conventional solenoid is eliminated, by disposing the solenoid in the bearing housing.

The present disclosure further provides a washing machine that can utilize the magnetic flux flowing from an armature to the dehydration shaft to lift the armature.

The washing machine of the present disclosure operates by a solenoid, and includes a clutch that performs a shaft-joint (or connection) or a shaft-joint release (or disconnection/separation) between the drive shaft and the dehydration shaft.

The drive shaft is an axis for rotating the pulsator. The drive shaft may be directly connected to the pulsator or connected by a planetary gear train.

The dehydration shaft is connected to the washing tub, and has a first hollow through which the drive shaft passes. At least a part of the dehydration shaft is formed of ferromagnetic material.

An upper side of the solenoid is provided with a bearing for supporting the dehydration shaft. At least a part of the bearing is formed of ferromagnetic material. A bearing housing is provided to accommodate the bearing, and the solenoid is installed in the bearing housing.

The bearing housing includes a first fixing core surrounding the outer circumference of the bearing, and a second fixing core extending downward from the first fixing core and surrounding the outer circumference of the solenoid.

Specifically, the bearing housing may include a cylindrical portion (or a tubular portion) that is extended in the vertical direction while surrounding the bearing and the solenoid, and the cylindrical portion may form a magnetic path. At least a part of the bearing housing is formed of ferromagnetic material.

The clutch is provided to be lifted along the dehydration shaft from the lower side of the solenoid. The clutch performs a shaft-joint coupling between the drive shaft and the dehydration shaft in a connection position, and performs a shaft-joint release between the drive shaft and the dehydration shaft in a disconnection position raised from the connection position by a magnetic force of the solenoid.

Specifically, the clutch may include an armature that is lifted by the magnetic force of the solenoid, and a clutch coupler that is lifted (or moved together with the armature) by the armature.

The armature may include a core base disposed below the cylindrical portion and extending outwardly from the clutch coupler, and a core outer portion extending upward from an outer circumference of the core base.

The magnetic flux generated by the solenoid is moved along the cylindrical portion, the core outer portion, the core base, the dehydration shaft, and the bearing. That is, the cylindrical portion, the armature (core outer portion and core base), the dehydration shaft, and the bearing form a magnetic path.

The inner circumferential surface of the clutch coupler defines a second hollow through which the dehydration shaft passes, and may be spline-jointed to the outer circumferential surface of the dehydration shaft so that the clutch coupler is lifted along the dehydration shaft.

The clutch coupler may perform a shaft-joint connection between the drive shaft and the dehydration shaft in a first position corresponding to the connection position, and perform a shaft-joint release between the drive shaft and the dehydration shaft in a second position corresponding to the disconnection position.

An upper end of the core outer portion may be located farther from the dehydration shaft than the cylindrical portion. The core outer portion may be further away from the dehydration shaft as it progresses toward the upper end from the core base.

The core outer portion may have a cylindrical shape extended along the outer circumference of the core base.

In the state where the armature is lowered to the connection position, the upper end of the core outer portion may be spaced apart from the lower end of the cylindrical portion of the bearing housing. In the state where the armature is raised to the disconnection position, the upper end of the core outer portion may be located above the lower end of the cylindrical portion of the bearing housing.

The core base may include an opening through which the dehydration shaft passes, and the armature may further include a core inner portion extending upward from the circumference of the opening. The core inner portion may be formed in a cylindrical shape surrounding the dehydration shaft.

The inner core portion may extend from the core base to a position lower than the outer core portion. The core inner portion is separated further downward from the cylindrical portion of the bearing housing or the bearing than the core outer portion. The clutch coupler may be coupled to the core inner portion. The clutch coupler may be a synthetic resin material.

An elastic member may be further included for applying a repulsive force in the downward direction to the clutch. The solenoid may include a bobbin having a hollow through which the dehydration shaft passes, and a coil wound around the bobbin.

The elastic member may be a coil spring disposed in the hollow in an outer insertion state to the dehydration shaft. The coil spring may be disposed between the bearing and the clutch coupler.

The cylindrical portion of the bearing housing may include a first fixing core defining an area in which the bearing is installed, and a second fixing core extending downward from the first fixing core and having a reduced inner diameter than the first fixing core.

The bobbin may include a cylindrical bobbin body portion around which the coil is wound, and an upper plate portion extended outward from an upper end of the bobbin body portion. The upper plate may be supported by a horizontal portion formed due to the inner diameter difference between the first fixing core and the second fixing core.

A washing motor having a rotor connected to the drive shaft, and a rotor hub connecting the rotor to the drive shaft may be further included. The clutch coupler may be engaged with the rotor hub in the connection position and may be separated from the rotor hub in the disconnection position.

