JP2011167426A - Dishwasher - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dishwasher, which includes a washing chamber with a high noise reduction effect with keeping the mechanical strength. <P>SOLUTION: The dishwasher includes a washing chamber 2 integrally formed of a resin at least part of which is three-layered structures 12 and 17 configured to sandwich inner layers 10 and 15 by outer layers 11 and 16, wherein the outer layers 11 and 16 are made of a non-foam material and the inner layers 10 and 15 are made of a foam material, which results in imparting rigidity to the three-layered structures configured to sandwich the foam inner layers 10 and 15 by non-foam outer layers 11 and 16 and easily reducing noise of the dishwasher by using the washing chamber 2 per se. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a dishwasher in which noise such as washing noise during washing is reduced.

  Conventionally, as means for reducing noise generated in a cleaning room, a sound absorbing material is disposed between the casing and the cleaning room (see, for example, Patent Document 1), and an impact prevention member is disposed between the cleaning room and the tableware basket. (For example, refer to Patent Document 2), and the outer surface of the cleaning chamber is coated with resin to provide a sound absorbing layer (for example, refer to Patent Document 3). In particular, as a means for reducing the noise generated when the cleaning water sprayed from the cleaning nozzle hits the wall surface of the cleaning chamber, an asphalt member having a predetermined thickness is disposed on the outer surface of the cleaning chamber, and between the cleaning chamber and the tableware basket. (For example, patent document 4) which arrange | positions the network-like structure to disperse | distribute, reducing water pressure.

  FIG. 3 is a cross-sectional view of the dishwasher described in Patent Document 1. A sound absorber 103 is disposed between the casing 101 and the cleaning chamber 102. This prevents the noise generated in the cleaning chamber 102 from leaking outside.

Japanese Patent Laid-Open No. 5-130965 JP 2001-112695 A JP 2002-282187 A JP 2004-148094 A

  However, the prior art described above is provided with a separate member such as a sound absorbing material for noise reduction, and does not impart noise reduction characteristics to the cleaning chamber itself. That is, the noise is still large for the cleaning room alone. As a single product of a dishwasher, although the noise is reduced to some extent, there is a problem that the manufacturing process becomes complicated due to the processing and attachment of another member. Moreover, there existed problems, such as the problem of the durability of joining by providing another member, the problem of the stain | pollution | contamination between another member and a washing | cleaning chamber, the problem of a weight increase and a dimension increase (or washing chamber volume reduction).

  The present invention solves the above-mentioned conventional problems, and provides a dishwasher in which noise is easily reduced by imparting noise reduction characteristics to the washing chamber itself while maintaining the mechanical strength of the washing chamber. For the purpose.

  In order to solve the above-described conventional problems, a dishwasher according to the present invention includes a three-layer structure in which a washing chamber is formed of a resin member integrally molded, and at least a part of the resin member sandwiches an inner layer portion between outer layer portions. And the said outer layer part is a non-foamed body, and the said inner layer part is formed with the foam.

  Accordingly, rigidity can be given by a three-layer laminated structure in which the inner layer portion of the foam is sandwiched between the non-foamed outer layer portions, and the noise of the dishwasher can be easily reduced by the washing chamber itself.

  The dishwasher of this invention can implement | achieve the noise reduction effect on the wall surface of washing room itself.

Sectional view of the dishwasher of the present invention (A) Cross-sectional view of the three-layer structure of the cleaning chamber of the present invention (b) Cross-sectional view of the three-layer structure of the cleaning chamber (top surface portion) of the present invention Cross-sectional view of a conventional dishwasher

  A first invention is a three-layer structure in which a cleaning chamber is formed of a resin member that is integrally molded, and at least a part of the resin member is composed of a non-foamed outer layer portion and a foamed inner layer portion. It is what. Thereby, since the thickness of the resin member can be increased with the same weight, the mechanical strength of the cleaning chamber can be ensured, and the noise in the cleaning chamber can be reduced.

  In the second invention, in particular, the portion of the cleaning tank formed of the three-layer structure according to the first invention is a portion where the cleaning water of the cleaning nozzle hits. Thereby, the noise and vibration which generate | occur | produce when a washing water hits the wall surface of a washing | cleaning chamber can be reduced efficiently.

  In the third invention, in particular, the portion of the cleaning tank formed of the three-layer structure of the first invention is the top surface portion of the cleaning chamber. By disposing the three-layer structure on the top surface portion where the cleaning water ejected from the cleaning nozzle at a high water pressure directly hits, the noise and vibration generated when the cleaning water hits the wall surface can be reduced efficiently.

  In the fourth invention, in particular, the resin member of the first to third inventions is molded with polypropylene resin, and the foaming ratio of the foam of the inner layer portion is in the range of 2.6 to 3.2 times, thereby cleaning The noise during cleaning can be reduced while maintaining the mechanical strength of the chamber.

  In the fifth invention, in particular, by adding talc to the resin member of the first to third inventions, uniform foaming can be achieved, and the rigidity of the cleaning chamber can be secured. Thereby, it is possible to reduce noise and vibration during cleaning while maintaining the mechanical strength of the cleaning chamber.

  In the sixth invention, in particular, the resin member of the fifth invention is molded of polypropylene resin, and the foaming ratio of the foam of the inner layer portion is in the range of 2.6 to 4.0 times. While maintaining the mechanical strength, noise during cleaning can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a sectional view of a dishwasher according to a first embodiment of the present invention. The basic configuration of the dishwasher includes a cleaning chamber 2 (2a, 2b, 2c) provided in the casing 1, a cleaning nozzle 3 provided at the bottom of the cleaning chamber 2 for injecting cleaning water, and storing the cleaning water. A cleaning pump 4 provided in the middle of a circulation path 21 connecting the cleaning nozzle 3 to the water storage section 22 to be stored, and a tableware basket 5 for storing objects to be cleaned such as tableware. The cleaning pump 4 causes the cleaning nozzle 3 to pump cleaning water. The cleaning chamber 2 is integrally formed by injection molding, but each member (for example, the top surface portion 2a, the side surface portion 2b, and the bottom surface portion 2c) may be combined after being integrally formed.

  In the case of a so-called drawer-type dishwasher in which the washing chamber 2 is pulled out in the front-rear direction from the casing 1 having an opening on the front surface, the molded product of the side surface portion 2b and the lower surface portion 2c is joined or integrally molded, and the top surface portion 2a is molded. Goods will be combined at the time of use.

  In the present embodiment, the cleaning chamber 2 includes a side surface portion 2b, a lower surface portion 2c, and a top surface portion 2a. The cleaning nozzle 3 is for injecting the cleaning water 6 pressurized by the cleaning pump 4, and is a member that can rotate around a rotation shaft, and has a large number of injection holes 7. A tableware basket 5 for storing tableware is provided directly above the washing nozzle 3.

  In the dishwasher according to the embodiment of the present invention, the washing chamber 2 itself has a three-layer structure in order to reduce washing noise such as water splashing sound, jetting sound, and operation sound of the washing pump 4 during washing. . Details will be described later.

  FIG. 2A is a schematic sectional view of the cleaning chamber 2. The cleaning chamber 2 is a three-layer structure 12 of an inner layer portion 10 and an outer layer portion 11 that sandwiches the inner layer portion 10 from both sides. The inner layer portion 10 is a foam and the outer layer portion 11 is a non-foamed body. The inner layer portion 10 holds the bubbles 13 by foaming a gas such as carbon dioxide during molding. The outer layer portion 11 is formed in a non-foamed state by rapid cooling during molding. These three-layer structures 12 are integrally molded simultaneously by adding a foaming agent to polypropylene pellets, injection molding, and cooling.

  Since the specific gravity is reduced by foaming the same amount of resin, the bending characteristics such as bending strength and bending elastic modulus are lowered. However, since the rigidity increases as the wall thickness increases, it is possible to maintain the mechanical strength of the structure. On the other hand, the sound insulation for reducing the noise becomes more effective as the weight of the resin member increases and the rigidity increases. That is, since the rigidity is increased by foaming, a sound insulation effect can be exhibited. Although the three-layer structure according to the embodiment has the same weight, the thickness is increased and the rigidity is increased because foaming is performed in the inner layer portion. In addition, since the outer layer portion is a non-foamed layer, a decrease in bending characteristics is minimized.

  The expansion ratio needs to be 2.6 times or more. By increasing the thickness of the foam, the rigidity increases and the noise and vibration in the cleaning room can be shielded and suppressed. As a result, the sound pressure level that can be heard outside is equal to that of the same amount of polypropylene that does not foam. It is because it falls. Here, the expansion ratio is a volume ratio when foaming is performed at a constant weight and when foaming is not performed, and is calculated from the thickness of the foam / the thickness when foaming is not performed at the same weight as the foam. . The expansion ratio needs to be 3.2 times or less. If it is larger than this, the noise reduction effect is enhanced, but the bending characteristics are lowered, and the mechanical strength of the cleaning chamber as a structure cannot be maintained.

  Thus, by making the wall surface of the cleaning chamber 2 itself a three-layer structure including a foam layer, noise during cleaning can be reduced.

(Embodiment 2)
The basic configuration of the dishwasher is the same as that of the first embodiment. In the second embodiment, the portion to be the three-layer structure 17 is only the top surface portion 2a of the cleaning chamber 2, and the resin member 19 contains talc. Here, the top surface portion 2 a of the cleaning chamber 2 is a separate member, and is configured to open and close an opening provided on the upper surface of the cleaning chamber 2. In order to form the three-layer structure 17, core back molding is performed at the time of injection molding. However, the smaller the member and the flatter the member, the easier and more easily the inner layer portion 15 is foamed. In the second embodiment, for example, it is particularly suitable for a drawer type dishwasher in which the inner lid is a separate member and opens and closes the opening of the cleaning chamber 2 in conjunction with the drawer operation.

The dishwasher according to the embodiment of the present invention reduces the cleaning sound such as the spraying sound, the spraying sound and the operation sound of the cleaning pump during the cleaning, and the cleaning water 6 sprayed from the cleaning nozzle 3 is added to the cleaning chamber 2. In order to reduce noise generated by direct contact with the top surface 2a, the top surface 2a
The structure itself is a three-layer structure 17. In particular, when the amount of tableware is small, since the pressurized washing water sprayed from the washing nozzle 3 directly collides with the top surface portion 2a, an impact sound is generated. The machine can suggest this impact sound.

  FIG. 2B is a schematic cross-sectional view of the top surface portion 2 a of the cleaning chamber 2. The three-layer structure 17 includes a foam inner layer portion 15, a non-foam outer layer portion 16, bubbles 18, and a talc-containing polypropylene resin member 19. Talc is a mineral composed of magnesium hydroxide and silicate, and functions as a nucleating agent for foaming gas. By using talc, fine and uniform bubbles 18 can be formed. The fine and uniform cell shape is superior in strength when compared at the same expansion ratio. Other inorganic fine particles such as calcium carbonate can be used instead of talc. The outer layer portion 16 is formed in a non-foamed state by rapid cooling during molding. These three-layer structures 17 are integrally molded simultaneously by adding a foaming agent and talc to polypropylene pellets, injection molding, and cooling.

  The expansion ratio needs to be 2.6 times or more and 4.0 times or less. If it is 2.6 times or more, the thickness is increased by foaming, the rigidity is increased, and the noise and vibration generated at the top surface where the cleaning water from the cleaning nozzle 3 directly hits can be shielded and suppressed. On the other hand, if the ratio is larger than 4.0 times, the sound insulation effect of noise and vibration is higher, but the mechanical strength as a product may not be maintained.

  As described above, by arranging the three-layer structure formed by containing talc in the top surface portion 2a directly contacted with the cleaning water, the noise and vibration can be efficiently reduced without the entire cleaning chamber 2 having a three-layer structure. be able to.

  Embodiments 1 and 2 will be described in more detail.

  First, a method for manufacturing the cleaning chamber 2 will be described. The raw material resin in the cleaning chamber 2 is a block copolymer of polypropylene, and about 30 wt% of sodium bicarbonate and 4 wt% of a master batch of a foaming agent containing a nucleating agent are mixed with pellets to obtain raw material pellets before molding. . In the case of mixing talc, if it is mixed from 10 wt% to 20 wt%, the foamability, strength and moldability are improved. In this embodiment, 16 wt% is mixed. Although sodium hydrogen carbonate was used as the foaming agent, an organic foaming agent such as azodicarbonamide may be used. It is also possible to mold by physical foam molding using a supercritical fluid.

  Raw material pellets are put into a hopper of an injection molding machine and injected at a cylinder temperature of 190 ° C to 230 ° C. In the cylinder, sodium hydrogen carbonate is thermally decomposed into carbon dioxide gas, and the mold is filled while bubbles are formed at the same time as injection. Then, after completion of the injection, the core portion of the mold is moved backward by a predetermined amount to obtain a molded product in which the inner layer portion is foamed and the wall thickness is increased while maintaining the solid weight. The predetermined amount to be retracted here is an amount determined by the expansion ratio. Further, after filling, the outer layer portion of the non-foamed body is formed by cooling at a mold temperature of 35 to 55 ° C. In this example, only the member of the top surface portion was produced. However, the side surface portion and the bottom surface portion can be further improved functionally, for example, noise can be further reduced by using a three-layer structure.

As described above, the cleaning chamber having the three-layer structure is completed. Bubbles are formed in the inner layer portion of the three-layer structure by foaming with carbon dioxide gas, and a non-foamed material containing no bubbles is formed in the outer layer portion by rapid cooling. The diameter of the bubbles is 100 to 200 μm, and the diameter of the bubbles becomes 60 to 120 μm by mixing talc. When the solid thickness is 2.2 mm, the expansion ratio is 2.6 times, the thickness of the inner layer portion is 3.6 mm, and the thickness of the outer layer portion is about 0.8 mm. For comparison, a solid molded product formed by a normal molding method in which the same amount of injection was performed without mixing the foaming agent and the core part was not retracted was used. The thickness of the top surface portion during normal formation is 2.2 mm and does not have a three-layer structure.

  Next, a bending test method, a stiffness evaluation method, and a noise test method will be described.

  The bending test was conducted by a three-point compression test based on JIS standard K-7203, and the bending elastic modulus and bending strength were measured. About rigidity, it evaluated by the load required in order to displace a test piece 2 mm in the said test. The determination of the mechanical strength as a product was comprehensively evaluated in consideration of the bending elastic modulus, bending strength, and rigidity of the molded product of the solid and three-layer structure.

  For the noise test, the actual cleaning operation was performed, and the presence or absence of the effect was evaluated from the degree of decrease in sound pressure. In order to improve the reproducibility of the test, the dish was not placed in the dish basket and the operation was started at room temperature without adding detergent. Therefore, the washing water passes through the tableware basket, directly hits the top surface (upper surface) of the washing room, and is scattered and scattered in all directions. The measurement used the average value for 3 minutes after a driving | operation. The microphone was placed 1 meter ahead from the center of the front of the dishwasher, and the sound pressure was measured. The presence or absence of a noise reduction effect as a product was determined by the difference in sound pressure between the solid molded product and the molded product of the three-layer structure.

  The test results are shown in Table 1. In the table, ○ means good, ◎ means very good, Δ means bad, and X means very bad. From this result, the following became clear.

  The noise reduction effect is effective when the expansion ratio is 2.6 times or more. In addition, the mechanical strength is unacceptable at an expansion ratio of 3.5 times or more, but by including talc, it is acceptable up to an expansion ratio of 4.0 times.

  As described above, the washing room of the dishwasher according to the present invention can increase the rigidity by foaming, and therefore can block the washing sound peculiar to the dishwasher, so that the noise effect is enhanced. It can be applied to dishwashers for the purpose.

2 Cleaning chamber 2a Top surface section 3 Cleaning nozzle 4 Cleaning pump 5 Tableware basket 6 Washing water 10, 15 Inner layer parts 11, 16 Outer layer parts 12, 17 Three-layer structure

Claims (6)

A dishwasher for washing dishes, comprising: a washing chamber for storing dishes; a washing nozzle provided in the washing chamber for injecting washing water into the tableware; and a washing pump for pumping washing water to the washing nozzle The cleaning chamber is composed of an integrally molded resin member, and at least a part of the resin member is a three-layer structure in which an inner layer portion is sandwiched between outer layer portions, and the outer layer portion is a non-foamed body and A dishwasher whose inner layer is made of foam. The dishwasher according to claim 1, wherein the portion of the washing tub formed by the three-layer structure is a portion to which the washing water of the washing nozzle hits. The dishwasher according to claim 1, wherein the portion of the washing tank formed by the three-layer structure is a top surface portion of a washing chamber. The dishwasher according to any one of claims 1 to 3, wherein the resin member is formed of a polypropylene resin, and the foaming ratio of the foam is 2.6 to 3.2 times. The dishwasher according to any one of claims 1 to 3, wherein the resin member contains talc. 6. The dishwasher according to claim 5, wherein the resin member is formed of polypropylene resin, and the foaming ratio of the foam is 2.6 to 4.0 times.

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