JP2013075047A - Washing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance corrosion resistance of a washing tub support bonded to an end of a washing tub.SOLUTION: This washing machine comprises: the washing tub made of stainless steel; the washing tub support formed by die-casting an aluminum alloy; and a nonconductive coating (nonconductive layer) 29 for blocking electrical connection between a support leg 18 of the washing tub support and an end plate 9 of the washing tub, which is provided between a surface of the washing tub and a surface of the washing tub support.

Description

  The embodiment relates to a washing machine.

  Some washing machines have a washing tub and a washing tub support. The washing tub has a cylindrical shape with one end on the user side open and the other end closed, and the clothes are put into the washing tub through one end of the washing tub. The washing tub support is joined to the other end of the washing tub. The washing tub support mechanically reinforces the washing tub, and a rotation shaft of a washing motor for rotating the washing tub is fixed to the washing tub support.

JP 2006-223564 A

  In the case of a conventional washing machine, the washing tub is formed of stainless steel, and the washing tub support is formed by die-casting an aluminum alloy. For this reason, galvanic corrosion in which the washing tub support is eroded by battery action may occur.

  The washing machine of the embodiment has a non-conductive water receiving tub that receives water, and a cylindrical shape that is provided in the water receiving tub and has one end opened and the other end closed. A washing tub made of stainless steel through which clothes are put, and a washing tub support provided in the washing tub to mechanically reinforce the washing tub and die cast aluminum alloy, A feature is that a non-conductive non-conductive layer for electrically blocking the laundry tub support from the washing tub is provided between the surface of the washing tub and the surface of the washing tub support.

The figure which shows Example 1 (sectional drawing which shows the internal structure of a washing machine) Perspective view showing the appearance of the drum Sectional view along X-ray in FIG. FIG. 3 equivalent diagram showing the second embodiment.

  The outer box 1 in FIG. 1 has a hollow shape formed by joining a front plate, a rear plate, a left side plate, a right side plate, a bottom plate and a top plate to each other. An entrance / exit 2 made of a hole is formed. A door 3 is attached to the front plate of the outer box 1. The door 3 can be operated by the user, and the doorway 2 is opened and closed in response to the operation of the door 3.

  As shown in FIG. 1, a water receiving tank 4 is fixed in the outer box 1. The water receiving tank 4 has a circular rear plate and a cylindrical tube plate surrounding the rear plate, and is disposed in an inclined state in which the axial center line CL descends from the front to the rear. The water receiving tank 4 receives water for washing clothes and is formed of a non-conductive synthetic resin.

  A water supply valve is fixed in the outer box 1. This water supply valve has an inlet and an outlet, and the inlet of the water supply valve is connected to a water tap. This water supply valve uses a water supply valve motor as a drive source, and the outlet of the water supply valve is switched between an open state and a closed state in response to the rotation operation of the water supply valve motor. The outlet of the water supply valve is connected to the water receiving tank 4, and tap water is injected into the water receiving tank 4 through the water supply valve when the water supply valve is open.

  As shown in FIG. 1, an upper end portion of a drain pipe 5 is connected to the water receiving tank 4, and a drain valve 6 is interposed in the drain pipe 5. The drain valve 6 uses a drain valve motor as a drive source, and is switched between an open state and a closed state in accordance with the rotation of the drain valve motor. When the drain valve 6 is closed, tap water injected into the water receiving tank 4 from the outlet of the water supply valve is stored in the water receiving tank 4, and when the drain valve 6 is opened, tap water in the water receiving tank 4 is drained from the drain pipe 5. It is discharged to the outside of the water receiving tank 4 through.

  As shown in FIG. 1, a drum 7 corresponding to a washing tub is accommodated in the water receiving tub 4. As shown in FIG. 2, the drum 7 includes a stainless steel (SUS) tube plate 8 and a stainless steel end plate 9, and each of the tube plate 8 and the end plate 9 has a plurality of through holes. A hole 10 is formed. The tube plate 8 has a cylindrical shape in which each of the front surface and the rear surface is open, and the end plate 9 has a circular shape that closes the rear surface of the tube plate 8. 11 is formed. As shown in FIG. 1, the joining portion 11 has a cylindrical shape oriented in the front-rear direction, and the end plate 9 is formed by joining the joining portion 11 to the inner peripheral surface of the tubular plate 8 in a contact state. It is fixed to the plate 8.

  The end plate 9 of the drum 7 is formed with a storage portion 12 as shown in FIG. The storage portion 12 has a concave shape with an open rear surface, and a drum support 13 corresponding to a washing tub support is stored in the storage portion 12 as shown in FIG. The drum support 13 is formed by die-casting an aluminum alloy, and has a mechanical reinforcing function for supporting the tube plate 8 of the drum 7 from the inside of the tube plate 8.

  As shown in FIG. 2, the drum support 13 has a bearing 14 and a center support 15. The bearing 14 has a cylindrical shape with an open front surface and a closed rear surface, and the central support 15 has a cylindrical shape with an open front surface and a closed rear surface. The central support 15 is disposed concentrically with the bearing 14 on the outer peripheral portion of the bearing 14, and a plurality of radiation ribs 16 are integrally formed on the central support 15. Each of the plurality of radiating ribs 16 has a plate shape protruding from the inner peripheral surface of the central support 15 and is connected to each other via a bearing 14 at a radial tip portion, and is cylindrical at a midway portion in the radial direction. Are connected to each other via cylindrical ribs 17.

  As shown in FIG. 2, three support legs 18 are integrally formed on the center support 15. Each of these three support legs 18 protrudes from the outer peripheral surface of the central support 15 and is arranged at equal pitches in the circumferential direction. Each of the three support legs 18 is integrally formed with a plurality of vertical ribs 19 and a plurality of horizontal ribs 20. Each of the plurality of vertical ribs 19 has a plate shape protruding from the outer peripheral surface of the center support 15, and each of the plurality of horizontal ribs 20 connects each of the plurality of vertical ribs 19 for each support leg 18. One attachment plate 21 is integrally formed at the tip of the plurality of vertical ribs 19 for each support leg 18. Each of these three mounting plates 21 is opposed to the inner peripheral surface of the cylindrical plate 8 of the drum 7 in the radial direction, and each of the three mounting plates 21 is formed with a plurality of screw holes, and the plurality of screw holes A screw 22 is screwed into each of these through the through hole of the cylindrical plate 8 of the drum 7 and the through hole of the joint portion 11 of the end plate 9 in order. Each of the plurality of screws 22 is made of stainless steel, and the drum support 13 is fixed to the drum 7 by the fastening force of the plurality of screws 22. Each of the plurality of screws 22 corresponds to a fastening member.

  As shown in FIG. 1, a washing motor 23 is fixed to the rear plate of the water receiving tank 4 so as to be located outside the water receiving tank 4. The washing motor 23 has a rotating shaft 24 that protrudes into the water receiving tank 4, and the axis of the rotating shaft 24 is disposed so as to overlap the axis of the water receiving tank 4. The rotation shaft 24 is fixed to the bearing 14 of the drum support 13 via a bolt, and the drum support 13 and the drum 7 rotate integrally with the rotation shaft 24 of the washing motor 23 in the operation state of the washing motor 23. . In the drum 7, clothes are put in and out through the front surface of the water receiving tank 4 and the front surface of the drum 7 with the door 3 opened. The axial center line of the drum 7 overlaps the axial center line CL of the water receiving tank 4. Has been placed.

  A circulating air passage 25 is fixed in the outer box 1 as shown in FIG. The circulating air passage 25 has an inlet connected to the front end of the water receiving tank 4 and an outlet connected to the rear end of the water receiving tank 4, and a fan 26 is accommodated in the circulating air passage 25. . The fan 26 is connected to the rotating shaft of the fan motor 27. When the fan motor 27 is in operation, the fan 26 rotates so that the air in the water receiving tank 4 flows from the inlet of the circulating air passage 25 to the circulating air passage 25. Enter inside. The air that has entered the circulating air passage 25 flows from the front to the rear in the circulating air passage 25 and is discharged from the outlet of the circulating air passage 25 into the water receiving tank 4. A heater 28 is fixed in the circulating air passage 25, and in the respective operating states of the fan motor 27 and the heater 28, the air in the circulating air passage 25 is heated by the heater 28, so that the clothes in the drum 7 are removed. It becomes dry air to dry.

  A circulating water passage is fixed in the outer box 1. This circulating water passage has an inlet connected to the bottom of the water receiving tank 4 in the water receiving tank 4 and an outlet connected to the top of the water receiving tank 4 in the water receiving tank 4. Is intervened. This circulation pump uses a pump motor as a drive source. When the pump motor is operated with water stored in the water receiving tank 4, the water in the water receiving tank 4 circulates from the inlet of the circulating water passage. Enter the water passage. The water that has entered the circulating water passage flows from the bottom to the top along the circulating water passage, and is discharged from the outlet of the circulating water passage so that the clothes in the drum 7 are bathed from above. A filter is inserted in the circulating water passage. This filter captures foreign matter from the water in the circulating water passage and is detachable from the circulating water passage.

  The drum support 13 is formed by aluminum die casting in which a molten aluminum alloy is poured into a mold. In this aluminum die casting, the dimension of the molded product is generally difficult to match the target dimension, and the weight balance of the drum support 13 is achieved by scraping most of the surface of the drum support 13 after the drum support 13 is die-cast. It is matched to. For this reason, since the oxide film and the silicone film are removed from the surface of the drum support 13, there is a situation in which corrosion tends to proceed on the surface of the drum support 13.

  The aluminum alloy of the drum support 13 contains a copper component. The surface of the drum support 13 comes into contact with water in the water receiving tank 4. This water contains a detergent, and the detergent contains an alkaline component such as sodium carbonate. That is, the surface of the drum support 13 is in contact with the alkaline component in the water receiving tank 4, and when the surface of the drum support 13 is in contact with the alkaline component, the surface of the drum support 13 is caused by local battery action. May be eroded. In particular, aluminum is an amphoteric metal and corrodes when not only acids but also alkaline detergents come into contact with foreign metals. The following formula is a reaction formula in an alkali, and aluminum becomes aluminate ions and generates hydrogen gas.

Al + 2OH ⁻ → AlO ₂ ⁻ + H ₂ + 2e ⁻
Al is base as a metal, and a high electrode potential is required to exist with metal Al. Al ₂ O ₃ serving as a non-moving body film exists only at a pH of about 4.2 to 9.0, and exists as Al ³⁺ ions in a low acid region, and Al dissolves by generating hydrogen. In the alkaline region of the detergent, when the pH is 9 or more, an immobile body film is not formed and dissolves as aluminate ions. In particular, in the alkali region, the electrode potential difference can be large, so that the progress is accelerated. That is, even in the alkaline state of a detergent solution that is difficult to corrode with metals such as iron, the non-moving body film becomes unstable, and corrosion proceeds. In particular, when a different metal comes into contact with aluminum, there is a high possibility that the corrosion proceeds with a base aluminum as compared with the different metal.

  If the drum support 13 is eroded, the strength of the drum support 13 is reduced and the weight balance is lost. This causes vibration and noise. To prevent this, there is a measure to increase the drum support 13 so that the strength is not reduced even if the drum support 13 is slightly eroded. In this measure, the amount of aluminum alloy used is more than necessary, which increases the cost and weight, and also increases the amount of electric power required to rotate the drum 7 with the washing motor 23, thereby saving energy. It will be contrary.

  When the drum support 13 is eroded, the aluminum oxide is detached from the drum support 13 and becomes powdery. For this reason, in the operating state of the circulation pump, the powdery foreign matter circulates and adheres to the clothes in the drum 7, and particularly in the case of dark-colored clothes, the powdery foreign matter adheres to the clothes in spots. In addition, since powdery foreign matter accumulates in the filter in the circulating water passage, the function of the filter may deteriorate and water may leak.

  The corrosion resistance of the drum support 13 is improved by subjecting the surface of the drum support 13 to an alumite treatment. However, ordinary alumite treatment is often performed with high-purity aluminum, and when a large amount of silicone is contained as in aluminum die-casting, a dense alumite layer is not formed, and the alumite layer is soiled by different elements. Therefore, it is often difficult to process. The corrosion resistance of the drum support 13 can also be improved by providing a chromate layer with hexavalent chromium on the surface of the drum support 13. This hexavalent chromium is harmful and has environmental problems.

  As shown in FIG. 3, a non-conductive film 29 corresponding to a non-conductive layer is formed on the drum support 13. The non-conductive coating 29 is formed by applying an acrylic resin-based paint only to a portion of the surface of the drum support 13 that contacts the drum 7. Specifically, the non-conductive coating 29 is formed on the front end surface of the center support 15. Each of the plurality of support legs 18 is formed on each circumferential side surface, each front end surface of each of the plurality of vertical ribs 19, each front end surface of each of the plurality of horizontal ribs 20, and each outer peripheral surface of each of the plurality of mounting plates 21. ing. The non-conductive coating 29 is interposed between the surface of the drum 7 and the surface of the drum support 13 so as to electrically insulate the drum support 13 from the drum 7. Corrosion of the drum support 13 due to local battery action due to contact is prevented.

  In general, for aluminum die casting, an Al—Si—Cu based aluminum alloy (ADC12 in JIS standard) is often used in terms of both mechanical strength and cost. .5% Cu is contained. When this Cu component is inside the drum support 13, there are microscopically high and low Cu portions inside the drum support 13. A local battery is likely to be generated between the low portions, which may cause a problem in corrosion resistance. In particular, when Cu is 3.5% or more, which is the upper limit value of the ADC 12, if the distribution on the surface is uneven, the corrosivity is extremely increased. Further, also in contact with the drum 7, potential generation can be suppressed during that time, and the progress of corrosion can be suppressed. The drum support 13 has a Cu component ratio of 1.5% or more and 3% or less, and prevents the formation of a local battery. Even when a non-conductive coating 29 is provided therebetween to suppress erosion, the drum support 13 is non-conductive. The effect of suppressing erosion by the coating 29 can be enhanced.

  Each of the plurality of screws 22 is made of stainless steel. When each of the plurality of screws 22 comes into contact with the drum support 13 on the inner peripheral surface of the screw hole of the mounting plate 21, a local battery is formed. In addition, the mounting plate 21 of the drum support 13 may be corroded in an alkaline aqueous solution. A non-conductive layer is formed on the surface of each of the plurality of screws 22. Each of the plurality of non-conductive layers is made of an epoxy adhesive, and the screw 22 is screwed into the screw hole of the mounting plate 21 so that the hardener contained in the microcapsule in the adhesive is crushed and solidified. When the curing agent is solidified, the screw 22 is difficult to be removed from the screw hole of the mounting plate 21 and a nonconductive layer is formed between the surface of the screw 22 and the inner peripheral surface of the screw hole. Each of these non-conductive layers electrically shields the mounting plate 21 of the drum support 13 from the screws 22 and prevents the mounting plate 21 of the drum support 13 from corroding.

According to the said Example 1, there exists the following effect.
Since the non-conductive coating 29 that electrically shields the drum support 13 from the drum 7 is provided between the surface of the drum 7 and the surface of the drum support 13, the drum support 13 is prevented from being corroded by battery action. The For this reason, the strength reduction of the drum support 13 is prevented, the vibration and noise due to the loss of the weight balance of the drum support 13 are prevented, the amount of aluminum alloy used is prevented from being increased, and the filter in the circulation channel is powdered. The clogging with the foreign matter is prevented, and the powdery foreign matter is prevented from adhering to the clothes in the drum 7. In addition, since it is possible to prevent an increase in the amount of electric power for rotating the drum 7, energy saving can be achieved.

  Since the non-conductive coating 29 is provided by applying an organic paint only to the portion of the surface of the drum support 13 that contacts the drum 7, the corrosion resistance of the drum support 13 is improved with a coating surface treatment of a minimum area. be able to. Since the drum support 13 is die-cast using an aluminum alloy having a copper component ratio of 1.5% or more and 3% or less, the effect of suppressing erosion by the non-conductive coating 29 can be enhanced. Since the non-conductive layer that electrically shields the drum support 13 from the screw 22 is provided between the surface of the screw 22 and the drum support 13, it is possible to prevent the mounting plate 21 of the drum support 13 from being corroded.

  As shown in FIG. 4, a polyester film 30 corresponding to a non-conductive layer is interposed between the drum 7 and the drum support 13. This film 30 electrically insulates the drum support 13 from the drum 7, and the organic paint prevents corrosion of the drum support 13 due to local battery action caused by contact between aluminum and stainless steel. Prevent without.

In the first embodiment, the non-conductive film 29 may be formed by applying an epoxy resin-based or silicone resin-based paint to the surface of the drum support 13.
In the first embodiment, the non-conductive coating 29 may be formed by applying an acrylic resin, epoxy resin, or silicone resin paint to the surface of the drum 7.

In the first embodiment, the non-conductive coating 29 may be formed by applying an epoxy resin-based or silicone resin-based coating to the entire surface of the drum support 13.
In the first embodiment, the non-conductive coating 29 may be formed by applying an acrylic resin, epoxy resin, or silicone resin coating to the entire surface of the drum 7.

  In the first embodiment, a nonconductive layer of aluminum oxide containing phosphorus may be formed instead of the nonconductive film 29. This layer is formed by chemically forming a phosphate coating on the surface of the drum support 13 using a phosphate solution such as zinc phosphate, and electrically shuts off the drum support 13 from the drum 7. Thus, corrosion of the drum support 13 due to local battery action is prevented.

  In the first embodiment, a non-conductive layer made of an organic coating film or an anaerobic organic adhesive may be formed on each surface of the plurality of screws 22. In this case, each of the plurality of screws 22 is screwed into the screw hole of the mounting plate 21 of the drum support 13, whereby oxygen is blocked and an organic coating can be formed.

In Example 2, a film made of polyethylene or polypropylene may be used instead of the film 30 made of polyester.
Each of the above Examples 1 and 2 is an exemplification, and the scope of the invention is not limited thereto. In addition, although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the 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.

  4 is a water receiving tub, 7 is a drum (washing tub), 13 is a drum support (washing tub support), 22 is a screw (fastening member), 29 is a non-conductive coating (non-conductive layer), and 30 is a film (non-conductive layer). ).

Claims (6)

A non-conductive water receiving tank for receiving water;
A stainless steel washing tub that is provided in the water receiving tub, has a cylindrical shape with one end open and the other end closed, and into which clothing is put through the one end.
Provided in the washing tub, and mechanically reinforcing the washing tub, comprising a washing tub support formed by die-casting an aluminum alloy,
Between the surface of the washing tub and the surface of the washing tub support, a non-conductive non-conductive layer for electrically blocking the washing tub support from the washing tub is provided. Washing machine.   The washing machine according to claim 1, wherein the non-conductive layer is provided by applying an organic paint on a surface of the washing tub or a surface of the washing tub support.   The washing machine according to claim 1, wherein the non-conductive layer is provided by interposing an organic film between the surface of the washing tub and the surface of the washing tub support.   The washing machine according to claim 1, wherein the non-conductive layer is made of an aluminum oxide layer containing phosphorus provided on a surface of the washing tub support.   The washing machine according to any one of claims 1 to 4, wherein the washing tub support is made of an aluminum alloy having a copper component ratio of 1.5% or more and 3% or less. A fastening member made of stainless steel that fixes the washing tub and the washing tub support to each other,
The non-conductive non-conductive layer for electrically blocking the laundry tub support from the fastening member is provided between the surface of the fastening member and the washing tub support. The washing machine according to any one of 1 to 5.

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