EP2201167B1 - Plastic suds tub for a washing machine or a washer/dryer - Google Patents

Abstract

A plastic suds tub for a washing machine includes a cylindrical casing, an end face wall closing off the casing with a hollow-cylindrical, solid bearing mount, a stabilizer on the end face wall of a more solid and higher-quality plastic than the casing, and reinforcement ribs molded into the stabilizer or end face wall. The reinforcement ribs being radially-aligned from the bearing mount and branching along their radial extent.

Description

The invention relates to a plastic tub for a washing machine, in particular for a washing machine with a front opening for loading and unloading of the device with the laundry, which plastic tub a cylindrical shell and a jacket closing end wall with a hollow cylindrical, cavity-free bearing mount for a bearing of a shaft of a washing drum rotatable in the tub and means for stabilization, wherein as means for stabilizing the end wall from the outside an additional stabilizing member is placed, and wherein in the stabilizing member and / or in the front side wall reinforcing ribs are formed.

Such a plastic tub emerges from the GB 2 189 511 A ,

The invention relates to a washing machine with a housing and a spring-mounted therein washing unit, wherein the washing unit includes a cylindrical plastic tub, a rotatably mounted laundry drum, whose axis has a substantially horizontal orientation, and a drive motor, the laundry drum directly or driven by the intermediary of a pulley from the outside. For storage of the drum shaft, the end wall of the tub on a bearing support.

When operating the washing machine, especially when spinning, tremendous turning and bending forces occur, which are transmitted from the rotatable laundry drum to the tub. The load of the tub increases with the size of the drum and the load. The dynamics of the forces acting on the tub are dependent on the speed of the laundry drum, the effect of force on the tub increases particularly during drum run-up.

According to the WO 2005/052243 A1 consists of a container for laundry in a washing machine and a clothes loader therein, which is drivable from outside the container by means of a disc-shaped drive element, wherein at least one of the facing surfaces of the container and the drive element is surface-structured, the risk that the surface structures in the washing machine with each other to become a vibration exciter, in the Centrifugal operation gives off disturbing noises. According to WO 2005/052243 A1 this risk is thereby at least reduced, that at least one of the two surfaces is provided with a cover which compares the surface structure.

For front-loading washing machines, the drum is mounted on one side. In these washing machines known as front loaders, the bending and rotational forces transmitted by the laundry drum must be absorbed by the bearing receptacle in the end wall of the tub and be transferred or distributed over a large area thereof. The mechanical strength requirements are particularly high in this washer type. The design of such a tub must have sufficient strength to withstand all loads in the long term, it being considered for the construction of the tub that the mechanical stress in the bearing receptacle is highest and starting from the bearing receptacle on the front side wall reduced towards the container casing.

Assuming that the lifetime of a washing machine is more than 10 years, a tub must be designed so that it can fulfill all functional requirements for such a long period of time, in particular with regard to the durability against the mechanical stresses transmitted by the drum, as well in terms of waterproofness and corrosion resistance.

Furthermore, it must be required of a modern mass-produced product such as washing machines that their individual components, as in the present case the tub, not only meet the functional requirements, but they must also be economical to manufacture and easy to recycle when the washing machine Has reached the end of its life.

So that the tub can permanently fulfill all functional requirements, in particular with respect to the mechanical loads is sufficiently stable, washing tubs for washing machines from the prior art are known in which additional the liquor container stabilizing agent can be used in many forms.

A special tub construction is used in the DE 199 52 991 A1 proposed. To the tub against the incoming and to be diverted To optimize mechanical forces, the tub is constructed of an inner part of a alkali-resistant material such as stainless steel or plastic and an outer part in the form of a support structure for receiving forces and for distributing the mass of the aggregate.

The implementation of such a construction in manufacturing is associated with a considerable cost of materials and is also technologically very expensive. Overall, such a tub is not suitable for economical mass production.

In their application are widely used tubs, in whose end wall a metallic bearing cross is used. An example of such a tub is in the Scriptures EP 1 528 136 A2 released. It is proposed in the region of a front wall to arrange a preferably made of cast iron supporting contour, in the center of a bearing seat for flying support of the drum is arranged by receiving a shaft journal connected to it, wherein the supporting contour is at least approximately completely embedded in the material of the end face. For safe dissipation of forces and high temperatures from the storage area, the supporting contour has at least one or more radially extending arms.

It is known to produce such plastic containers by injection molding, that in the form of the injection molding machine first the bearing cross is arranged and then the injection takes place itself. The encapsulation of the bearing cross its firm fit is made possible in the front wall.

The processes for the production of lye containers with encapsulated bearing cross are technologically complex and costly. In addition, the injection molding process also technically has a number of problems and disadvantages that derive from the fact that materials are used which have very different properties:

Since the said liquor containers on the one hand to a container made of plastic and on the other hand to a bearing cross made of metal, their different material properties affect the cooling process after injection disadvantageously in such a way that due to the different expansion coefficients and the different thermal conductivities it after the encapsulation of the metallic bearing cross in the tub to considerable Tension comes from the fact that the plastic shrinks on cooling to room temperature.

The forces acting on the bearing cross are so great that the bearing cross can deform. A major disadvantage is that it can lead to cracking in the plastic and delamination at the interfaces of the two different materials, which can lead to loss of tightness of the tub and to loosening the bearing cross in the front wall after prolonged use. Another problem is that the plastic in the interior of the material cools differently than at the interface of the bearing cross. As a result, micro gaps form between the plastic and the bearing cross, which deteriorates the bond between the materials and can lead to cracking.

Of the WO 2004/042133 A1 is to remove a tub, which has a metallic bearing bowl, which receives a plastic body in an injection molding process, which is stronger and better quality than the plastic from which the tub is made. The metallic bearing bowl and the plastic body form a structural unit to which the plastic tub is sprayed in a further process step.

By this method, the above-described cracking in the storage area to be counteracted. The proposed construction offers the further advantage that the additional body made of stronger plastic gives the tub a higher mechanical stability in the area of the bearing receptacle. The disadvantage of the construction is that the stabilizing effect of the additional body is limited to the area of the bearing receptacle. On the stability of other areas of the tub, in particular on the bearing housing containing end wall of the tub, the solid plastic body does not or only marginally.

As an alternative to the described plastic tote containers with the bearing cross integrated in the end wall, lye containers have been developed whose stabilizing means are made of plastic. Due to the possible standardization of the technology, this will not be negligible Rationalisierungspotentiale, the production of the tub is possible with a technically and economically significantly reduced effort.

In the DE 20 2004 012 221 U1 For example, a tub is described, the rear end wall is provided with a plurality of straight, stiff ribs which are arranged at equal angular distance from each other and starting from the continuous bearing receptacle, which is arranged in the middle of the rear end wall, radially towards the outer edge of the end wall run.

Lye containers are also known which, in addition to the radial reinforcing ribs, have meandering, star-shaped, oval-shaped, circular or spherical shaped relief profiles in the region of the end wall. The profiles are designed in such a way that they are well suited for force courses of several directions.

Such tubs have a higher strength compared to the aforementioned example. A disadvantage of these lye containers, which comes in the crossing regions of the various relief profiles to material clusters, which cause due to the partially different temperature gradients that the material shrinks differently after injection molding. The result is material stresses within the front wall with the resulting risk that it may cause cracking in the material and after prolonged use to the fact that the tub is leaking.

The described known constructions of liquor containers with stabilizing agents made of plastic are not or only partially applicable for larger loading volumes and very high spin speeds.

The strength of such a constructed tub can be increased to some extent by making the material thickness of the end wall and / or the stabilizer molded therein higher or stronger or using stronger plastics. Since firmer plastics substantially increase the cost of the tub and reinforcing the end wall and the relief profiles leads to material clusters, the two possibilities for reinforcing the end wall are set relatively narrow limits. In particular, in the modern machines with spinning speeds of the rotary drum over 1500 revolutions and a load of more than 8 kg are the known constructions of Lye containers with stabilizers consisting exclusively of plastic, can not be used.

It is an object of the invention to form a lye container with stabilizing agents exclusively of plastic so that the stability of the tub is so high that it can meet the requirements of modern washing machines. It is at the same time an object of the invention to design the construction of the tub so that the technological effort for the preparation of the tub and the use of materials can be reduced to a minimum.

According to the invention the object is achieved by the features listed in claim 1. Advantageous embodiments of the invention are specified in the respective subsequent subclaims, whose features can be used individually or in any combination with each other or with the features of claim 1.

The designed in accordance with the present invention plastic tub for a washing machine, especially for a washing machine with a front opening for loading and unloading of the device with the laundry, which plastic tub a cylindrical shell and a jacket closing end wall with a hollow cylindrical, cavity-free bearing mount for a bearing of a shaft rotatable in the tub laundry drum and means for stabilization, being provided as means for stabilizing the end wall from the outside an additional stabilizing component, and wherein formed in the stabilizing member and / or in the end wall reinforcing ribs are distinguished by the fact that the reinforcing ribs comprise radially oriented reinforcing ribs, which branch at least once along the radial extent of the bearing seat, and in that the stabilizing ribs Component consists of a stronger and better quality plastic than that of the shell.

The designed according to the invention tub is characterized by an extraordinary strength. The tub is sturdy enough to withstand the high mechanical stresses encountered during operation of washing machines with a higher drum volume and higher load of the Laundry drum to be transferred to the tub. The additional expense associated with the implementation of the invention is limited to the use of an additional component made of plastic. With this additional component, a lenticular, optionally divided into individual more or less separate segments segments cavity is formed on the corresponding end wall, which optionally a saving of material in the amount of 30% to 40% of the material, which for void-free reinforcing structures, in particular ribs or thicker walls, would have to be spent. The technologies for producing the additional stabilizing component and for connecting the stabilizing component to the front wall are known and manageable without problems.

The invention also allows a more flexible use of a given, designed for comparatively low load tub, the load is in particular determined by a maximum load capacity of laundry and a maximum spin speed for which the tub is designed. By this tub is equipped according to the invention with the additional stabilizing component, it can for a correspondingly increased load, determined in particular by an increased load capacity and / or increased maximum spin speed, allowed and used.

According to the invention an additional stabilizing component is placed as a means for stabilizing the end wall from the outside, for which a firmer and better quality plastic than for the tub container jacket is used.

The stabilizing component and the end wall of the tub are also preferably welded together. Tests have shown that talc-reinforced polypropylene is the most suitable material for the tub casing and the front wall. This plastic is inexpensive and has a low modulus of elasticity. For the stabilizer component, the use of glass fiber reinforced polypropylene with a high modulus of elasticity has proved favorable. The materials can be easily processed by injection molding and can be easily welded together. In particular, a vibration welding method or ultrasonic welding method can be used.

According to the invention it is also preferred that the tub jacket and the stabilizing member are made of materials that are based on the same polymer to ensure the weldability of the two parts. The material of the tub container jacket additionally contains an inert, finely divided filler, in particular talc, not least to make the material cheaper. The material of the stabilizing component can be improved in particular by virtue of the fact that it contains less or no finely divided filler and / or additionally fibers, in particular glass fibers. Such fibers also contribute significantly to the increased strength of this material.

In order to significantly improve the strength of the tub, according to the invention reinforcing ribs are formed in the stabilizing component and / or in the end wall. The reinforcing ribs of the stabilizing component or the end wall and the surfaces of the end wall or the stabilizing member are formed corresponding to each other in such a way that the backs of the reinforcing ribs along their extension abut the mutual area without gaps and welded thereto along the contact line are. According to the invention, the reinforcing ribs have a radial extent which branches at least once along their radial extent.

Due to the number of molded reinforcing ribs and their different dimensions, as well as the option to einzuformen in the stabilizing member and / or in the front wall reinforcing ribs, can be made of the most effective use of material tubs of any type, which have a strength that exactly on the specific loads are turned off during operation of the washing machine.

A likewise particularly preferred embodiment of the invention provides that the reinforcing ribs comprise radially encircling reinforcing ribs which are in contact with radial circumferential reinforcing ribs of the stabilizing component. In particular, the bearing receptacle is touched by the stabilizing component. More preferably, at least one closed box is formed between the bearing receiver, the reinforcing ribs and the stabilizing component.

• Fig. 1: einen Laugenbehälter mit Stabilisierungs-Bauteil in Perspektivansicht, Beispiel 1;
• Fig. 2: einen Laugenbehälter mit Stabilisierungs-Bauteil in Perspektivansicht, Beispiel 2;
• Fig. 3: einen Laugenbehälter mit Stabilisierungs-Bauteil in Schnittdarstellung;
• Fig. 4: ein Stabilisierungs-Bauteil mit Rippen in Draufsicht;
• Fig. 5 einen Laugenbehälter mit Stabilisierungs-Bauteil in Perspektivansicht, Beispiel 3;
• Fig. 6: den Laugenbehälter der Fig. 5 in Rückansicht;
• Fig. 7: den Laugenbehälter der Fig. 6, geschnitten entlang der Linie A-A; und
• Fig. 8: den Laugenbehälter der Fig. 5, in vergrößerter Perspektivansicht mit teilweise weggebrochenem Stabilisierungs-Bauteil.

Hereinafter, exemplary embodiments of the invention will be described by way of example with reference to FIG to the accompanying drawings. Show it:

• Fig. 1 : A tub with stabilization component in perspective view, Example 1;
• Fig. 2 : a tub with stabilization component in perspective view, Example 2;
• Fig. 3 : a tub with stabilization component in section;
• Fig. 4 : a stabilizing member with ribs in plan view;
• Fig. 5 a tub with stabilization component in perspective view, Example 3;
• Fig. 6 : the tub of the Fig. 5 in rear view;
• Fig. 7 : the tub of the Fig. 6 cut along the line AA; and
• Fig. 8 : the tub of the Fig. 5 , in enlarged perspective view with partially broken stabilization component.

In Fig. 1 the rear part of a plastic tub 1 is shown in perspective from the front. This component 1 contains the front side wall 3 and is produced in one piece by injection molding. In a subsequent working section of this component 1 is firmly connected to the cylinder also made of plastic of the tub 1.

Centrally in the end wall 3, a hollow cylindrical, cavity-free bearing receptacle 2 is formed. This serves to receive a liquid-tight bearing, not shown, for the drive shaft to be arranged in the tub 1, also not shown laundry drum. The closer design of the hollow cylindrical bearing receptacle 2 takes place according to the specification according to the exact shape of the bearing to be used, whereupon it does not matter substantially here. In any case, there is the bearing holder 2 made of compact plastic without cavities, since the bearing holder 2 absorb the forces of the rotating, possibly with an imbalance laundry drum and must be designed accordingly robust and robust.

The present characteristic additional stabilizing component 5 is placed from the outside against the front side wall 3. The stabilizing component 5 is made of a stronger and better quality plastic. In the stabilizing member 5 reinforcing ribs 4 are formed, which extend radially on the bearing seat 2 to the edge of the end wall 3, wherein the height of the reinforcing ribs 4 decreases towards the edge. In the exemplary embodiment, the reinforcing ribs 4 have a triangular shape.

In Fig. 4 a preferred embodiment of the end wall 3 is shown in plan view from behind, in which the reinforcing ribs 4 branch once along its radial extent. The branching points 11 are arranged equally spaced from the bearing receptacle 2.

The Indian Fig. 2 Lye container 1 shown differs from the first example in that the reinforcing ribs 4 are part of the front side wall 3 and formed in this during injection molding. The stabilizing member 5 made of the stronger plastic has no ribs. It is in the nature of the matter that the tub 1 opposite to in Fig. 1 illustrated embodiment has a lower strength. This embodiment is suitable for smaller tub 1 with a lower load. In Fig. 3 is a sectional view of a preferred embodiment of the tub 1 shown. As in Example 2, the reinforcing ribs 4 are part of the front side wall 3. The shape of the reinforcing ribs 4 deviates from the triangular shape in Example 2 and is designed according to the overall construction of the washing machine. Due to the concavity 10 in the drum interior, the bearing seat 2 is extended without the capacity of the L is substantially reduced. The paragraph 6 is provided to accommodate the pulley, not shown, over which the laundry drum is driven to save space.

The wall thicknesses of the stabilizing component 5 and the end wall 3, the latter recognizable by the dashed line, decrease from the bearing seat 2 to the edge. The different material thickness is a further means to increase the stability of the components in areas or to limit to the extent necessary just taking into account an efficient use of materials.

From the drawing it can be seen that the contours of the inner surface of the stabilizing component 5 corresponding to the back line 9 of the reinforcing ribs 4 are the same shape. Assembled, both components lie against each other and can be welded completely along the contact line. When joining the two components, the rotationally symmetrical stabilizing component 5 is positioned in a simple manner over the bearing receptacle 2. Additional positioning aids are not required.

The FIGS. 5 to 8 show a third example of a tub 1, wherein only one half of the tub 1, which forms in particular a rear half of the complete tub 1, is shown. The half shown is to put together with a corresponding front half, which has another end wall with a correspondingly enlarged opening for the necessary access to a laundry drum to be placed in the tub 1. On the FIGS. 5 to 8 is hereby jointly referred to.

The illustrated half of the tub 1 comprises in the end wall 3 a central and substantially hollow cylindrical and cavity-free bearing receptacle 2, which accommodates a gray cast iron bearing housing 12. In the bearing housing 12 corresponding bearing for supporting a shaft, which serves to drive said laundry drum would be to place. All parts of the tub 1 except the bearing housing 12 are made of injection-molded plastic. At the end wall 3, the jacket 7 connects in a known manner. On the outside of the shell 7 are various moldings for attaching other components of the washing machine or the washer-dryer, to which or to which the tub 1 belongs. In the present case, these attachments are not essential, so you will not be talking about them any further.

On the outside, the front side wall 3 carries radial reinforcing ribs 4, which extend on the bearing receptacle 2 to the shell 7, and in addition a plurality of circumferential reinforcing ribs 13. The stabilizing member is placed on both the radial ribs 4 and on the circumferential ribs 13 and all welded thereto, so that closed boxes 14 are formed between the end wall 3 and the stabilizing component 5, each bounded by the radial ribs 4 and circumferential ribs 13, possibly also the bearing seat 2. In the area of the bearing receptacle 2, such boxes 14 result from the fact that the stabilizing component 5 directly contacts the bearing receptacle 2 and is also welded thereto. This is for the strength of the entire arrangement of great importance, since in this way between the stabilizing member 5 and the end wall 3, a lenticular, divided into the individual boxes 14 and otherwise only penetrated by the bearing seat 2 lenticular space is formed. This makes a high contribution to the stability and strength of the end wall 3 and the entire tub 1, since in this way both the front side wall 3 and its associated ribs 4 and 13 and the stabilizing member 5 together in the operation of the washing machine take the outgoing bearing housing 12 outgoing forces. Thus, even with a substantial saving of plastic material in comparison to a structure for the front side wall 3, which could do without a stabilizing component 5 - a highly stable and the operational forces occurring excellently adapted structure achieved.

The stabilizing component 5 may consist of the same material as the front side wall 3 and the jacket 7, but it is also conceivable and may be very advantageous to use a stronger and more robust material for the stabilizing component 5. In this way, the strength properties of the better material can be exploited, but the formation of the end wall 3 and the jacket 5 can continue to be done with a simpler material. In any case, a particularly heavy-duty and inexpensive to produce tub 1 is achieved.

LIST OF REFERENCE NUMBERS

1.

tub

Second

bearing seat

Third

End wall

4th

Reinforcing ribs, radial

5th

Stabilizing component

6th

Molding / sales

7th

coat

8th.

Axis of laundry

9th

topline

10th

concavity

11th

branch

12th

bearing housing

13th

Reinforcing ribs, circumferential

14th

box

Claims (6)

1. Plastics material solution container (1) for a washing machine, particularly for a washing machine with a frontal opening for loading and unloading the appliance with the stock to be washed, which plastics material solution container (1) comprises a cylindrical casing (7) and an end wall (3), which closes the casing (7), with a hollow-cylindrical cavity-free bearing mount (2) for a bearing of a shaft of a laundry drum rotatable in the solution container (1) as well as means (5) for stabilisation, wherein as means (5) for stabilisation of the end wall (3) and additional stabilising component (5) is placed on from the outside, and wherein reinforcing ribs (4, 13) are formed in the stabilising component (5) and/or in the end wall (3), characterised in that the reinforcing ribs (4, 13) comprise radially oriented reinforcing ribs (4) which beginning at the bearing mount (2) are branched at least once along their radial length and that the stabilising component (5) consists of a stronger and qualitatively better plastics material than that of the casing (7).
2. Plastics material solution container (1) according to the preceding claim, characterised in that the stabilising component (5) and the end wall (3) are welded together.
3. Plastics material solution container (1) according to one of the preceding claims, characterised in that the reinforcing ribs (4, 13) and the surfaces of the end wall (3) or of the stabilising component (5) are formed to correspond with one another in the manner that the backs of the reinforcing ribs (4, 13) bear, along their length, gaplessly against the opposite surface and are welded thereto.
4. Plastics material solution container (1) according to any one of the preceding claims, characterised in that the reinforcing ribs (4, 13) comprise encircling reinforcing ribs (13), which radially encircling reinforcing ribs (13) are contacted by the stabilising component (5).
5. Plastics material solution container (1) according to claim 4, characterised in that in addition the bearing mount (2) is contacted by the stabilising component (5).
6. Plastics material solution container (1) according to claim 5, characterised in that at least one closed box (14) is formed between the bearing mount (2), the reinforcing ribs (4, 13) and the stabilising component (5).

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