WO2017080702A1

WO2017080702A1 - Method for producing a shaft assembly for a domestic appliance, shaft assembly for a domestic appliance, and domestic appliance for treating laundry items

Info

Publication number: WO2017080702A1
Application number: PCT/EP2016/072108
Authority: WO
Inventors: Frank Emmerich; Juan Melantuche Fuente; Tom Weber
Original assignee: BSH Hausgeräte GmbH
Priority date: 2015-11-11
Filing date: 2016-09-19
Publication date: 2017-05-18
Also published as: DE102015222176A1

Abstract

The invention relates to a method for producing a shaft assembly 40 for a domestic appliance 10 for treating laundry items, wherein an end region 42 of a shaft 20 is connected to a support structure 34 designed to receive a laundry drum 18, and a radial bearing 44 is mounted on a bearing point 46 of the shaft 20. A radial shaft seal ring 50 is arranged in the region of a shaft 20 sealing point 48 arranged between the end region 42 and the bearing point 46 in order to seal the radial bearing 44. A bushing 28 is made of a non-corrosion resistant material and is rendered corrosion-resistant by means of a surface treatment and subsequently arranged on the sealing point 48 of the shaft 20. The invention further relates to a shaft assembly 40 for a domestic appliance 10 and to a domestic appliance 10 comprising a shaft assembly 40.

Description

A method of manufacturing a shaft assembly for a household appliance, shaft assembly for a household appliance and

The invention relates to a method for producing a shaft arrangement for a domestic appliance for the care of laundry items and a shaft assembly for a household appliance for the care of laundry items specified in the preamble of the independent claims. Furthermore, the invention relates to a household appliance for care of laundry with a shaft arrangement.

In household appliances for the care of laundry items, especially in front loader washing machines, usually a laundry drum is rotatably mounted on a shaft. For this purpose, usually an end region of the shaft is connected to a support structure designed for receiving the laundry drum, which is also referred to as a support star, wherein at least one radial bearing is mounted on a bearing point of the shaft. By means of the radial bearing, the shaft is mounted for example on a bearing housing.

A particular challenge is to achieve a reliable seal of the radial bearing, to prevent ingress of water, dust and detergent in the camp. It is known per se, to arrange a radial shaft seal to seal the radial bearing in the region of a arranged between the end and the bearing point sealing point of the shaft. The reliable sealing of such rolling bearings has a significant impact on the life of such household appliances.

Furthermore, there is usually still the problem that the shaft itself is exposed to water and in particular to washing liquor, at least in the region of said sealing point. Depending on the material composition of the shaft, this can lead to corrosion of the shaft, as a result, the life of the household appliance can be reduced.

It is the object of the present invention to achieve an increased life of a household appliance for the care of laundry, which a Shaft assembly comprising a shaft which is mounted by means of at least one radial bearing.

This object is achieved by a method for producing a shaft arrangement and by a shaft arrangement for a household appliance having the features of the independent patent claims. Advantageous embodiments with expedient and non-trivial developments of the invention are specified in the dependent claims. In the inventive method of manufacturing a shaft assembly for a home appliance for laundry care, an end portion of a shaft is connected to a support structure configured to receive a laundry drum and a radial bearing is mounted to a bearing of the shaft. For sealing the radial bearing, a radial shaft sealing ring is arranged in the region of a sealing point of the shaft arranged between the end region and the bearing point. It is inventively provided that a liner made of a corrosion-resistant material and made corrosion resistant by means of a surface treatment and is then arranged at the sealing point of the shaft. Thus, by means of the method according to the invention, a shaft arrangement is produced for a household appliance, in which the shaft is mounted by means of at least one radial bearing, which is arranged at a bearing point of the shaft. The shaft can be stored, for example by means of the radial bearing on a bearing housing. In order to ensure a reliable seal of the radial bearing, it is provided according to the invention to produce a bushing made of a corrosion-resistant material and to make corrosion resistant by means of a surface treatment and then to arrange the bushing at the sealing point of the shaft. The surface-treated liner is arranged in the manner at the sealing point of the shaft, that the radial shaft seal abuts the outer circumference of the bush, as a result, a particularly good sealing of the radial bearing can be achieved.

The fact that the bushing is made of a corrosion-resistant material, in particular of a non-stainless steel material, is a particular cost-effective production of the shaft assembly allows. In order to protect the liner against corrosion, this is subjected to a surface treatment according to the invention. The surface treatment takes place in such a way that the liner has such a surface finish that a particularly good seal can be achieved by the radial shaft sealing ring resting on the outside circumference of the liner. The surface treatment of the bushing, the properties of the bushing are further adjusted so that a sufficient temperature resistance and durability of the liner can be ensured.

The invention is based on the finding that the shaft is exposed to wash liquor in particular in the region of the sealing point during operation of the household appliance. As a result, in particular the sealing point of the shaft is at risk of prematurely corroding. Since the bushing according to the invention is subjected to a surface treatment, by means of which it is made corrosion resistant, the sealing point of the shaft can be particularly well protected against corrosion, since the bushing is arranged on the outer peripheral side at the sealing point of the shaft. This makes it possible that the shaft is made of a corrosion-resistant material and this is not subjected to a surface treatment by means of which the corrosion resistance of the shaft would be produced.

The shaft can thus be made, for example, from a relatively inexpensive, non-stainless steel material and installed in the shaft assembly without further surface treatment. Because of the arranged at the sealing point of the shaft bush, the shaft in the region of the sealing point, which is usually exposed to wash liquor, are protected in a reliable manner against corrosion. This contributes to a particularly simple and inexpensive manufacture of the shaft assembly. An advantageous embodiment of the invention provides that the liner is provided in the surface treatment with a chrome layer. As a result, a corrosion resistance of the liner can be achieved in a particularly simple and reliable manner, wherein in addition a particularly high surface quality can be achieved by the chrome plating of the liner. Alternatively or additionally, it can also be provided that the liner is provided with a nickel and / or copper layer in the surface treatment. Depending on the procedure, it may happen that the chromium layer has a dense network of very fine cracks due to the production process. Therefore, it may happen that sufficient corrosion protection can not be effected. The nickel and / or copper layer can be provided as a kind of intermediate layers, by means of which the reliable corrosion protection can be ensured. According to a further advantageous embodiment of the invention, it is provided that the liner is nitrocarburized in the surface treatment, whereby a nitrogen-enriched and carbon nitride layer is formed on the liner. By nitrocarburizing can be made on the one hand in a reliable way corrosion protection on the surface of the liner. On the other hand can be achieved by the Nitrocarburieren also a particularly high hardness of the liner.

In a further advantageous embodiment, it is provided that the support structure is produced by die casting, wherein at least the end portion of the shaft is encapsulated on the outer peripheral side by means of the support structure during the manufacture of the support structure for connecting the support structure with the end portion of the shaft. For example, the support structure made of aluminum can be produced by die-casting. The end region of the shaft can be arranged in the region of a cavity of a diecasting tool. Subsequently, the die casting tool is closed and the aluminum melt is injected into the cavity to produce the support structure. By encapsulating the end portion of the shaft, it can be connected to the support structure in a particularly simple and reliable manner. As a result of the integration into the die casting production method of the support structure, no further work steps are necessary to reliably connect the support structure to the end region of the shaft.

In an advantageous embodiment of the invention, it is also provided that, in addition, a part of the bushing arranged on the shaft is also encapsulated in the course of the die-casting process by means of the support structure. In other words, it may therefore be provided that first the bushing is arranged at the sealing point of the shaft and only then the End portion of the shaft and a part of the bushing is encapsulated in the course of the die-casting process by means of the support structure. This can be ensured in a simple manner that at the sealing point of the shaft during operation of the household appliance no wash liquor can get.

According to an alternative advantageous embodiment of the invention, it is provided that the bushing is arranged on the shaft after the end region of the shaft has been overmolded by means of the support structure. In this context, it is preferably provided that a sealing ring is arranged on the shaft between the bushing and the support structure. The sealing ring can be, for example, an O-ring, by means of which it can be ensured that no liquid gets between the bushing and the shaft.

The shaft arrangement according to the invention for a domestic appliance for the care of laundry items comprises a shaft with an end region which is connected to a support structure designed to receive a laundry drum. Furthermore, the shaft arrangement comprises a radial bearing mounted on a bearing point of the shaft, a radial shaft sealing ring being arranged in the region of a sealing point of the shaft arranged between the end region and the bearing point for sealing the radial bearing. The shaft arrangement according to the invention is characterized in that a bush made of a corrosion-resistant material and made corrosion-resistant by means of a surface treatment is arranged at the sealing point of the shaft. Advantageous embodiments of the method according to the invention are to be regarded as advantageous embodiments of the shaft assembly according to the invention.

The household appliance according to the invention for the care of items of laundry comprises the shaft arrangement according to the invention or an advantageous embodiment of the shaft arrangement according to the invention.

In an advantageous embodiment of the household appliance according to the invention, it is provided that the household appliance is a front loader washing machine. Under a front loader washing machine is a washing machine with a housing understood, which at its front a charging opening for loading the Laundry drum, wherein the laundry drum is rotatably disposed about a substantially horizontal or inclined axis of rotation. The invention is not limited to a front loading washing machine. It can also be used in so-called Topladerwaschmaschninen with a top on the housing lying feed opening and a substantially horizontal or vertical drum rotation axis.

The terms "top", "front", "horizontal", "vertical" indicate the positions and orientations given when the device is used and disposed of as intended and when an observer is standing in front of the device and looking towards the device.

Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments and from the drawing. The features and feature combinations mentioned above in the description as well as the features and feature combinations mentioned below in the description of the figures and / or shown alone in the figures can be used not only in the respectively specified combination but also in other combinations or in isolation, without the scope of To leave invention.

The drawing shows in:

1 is a schematic sectional view of a household appliance designed as a front loader washing machine;

Fig. 2 is a perspective view of a support structure for receiving a laundry drum of the front loading washing machine, the support structure being connected to a shaft to which a liner is attached;

3 is a side sectional view showing a bearing of the shaft of the household appliance, showing inter alia the arrangement of the bushing on the shaft, Fig. 4 is another side sectional view showing the shaft connected to the support structure, the support structure partially surrounding the bushing on the outer peripheral side; and in

Fig. 5 is another side sectional view showing an alternative embodiment in which the bushing is disposed entirely outside of and abutting against the support structure.

In the figures, identical or functionally identical elements are provided with the same reference numerals.

In Fig. 1, a designed as a front loader washing machine 10 home appliance for the care of laundry is shown in a longitudinal sectional view. The front loader washing machine 10 comprises a housing 12 in which a vibration system 14 is arranged. The oscillating system 14 includes a tub 16 of the front loader washing machine 10. In addition, the front loader washing machine 10 includes a laundry drum 18 which is rotatably mounted in the embodiment shown here about an axis A, which is oriented substantially horizontally and thus in the longitudinal direction x of the front loader washing machine 10.

The laundry drum 18 is designed to receive items of laundry and surrounded by the tub 16. The laundry drum 18 is rotatably supported by a shaft 20 whose axis is also oriented in the longitudinal direction x and coaxial with the axis A. For driving the laundry drum 18, a pulley 22 and a belt may be provided, which are drivable via a motor 26, for example in the form of an electric motor. The oscillating system 14 further comprises springs 28 and at least one shock absorber 30.

The front loader washing machine 10 comprises a supporting star 32 serving as a supporting structure for the tub 16. Furthermore, the front loading washing machine 10 has a supporting star 34 serving as a supporting structure for the washing drum 18. As can be seen, the carrying star 34 for the laundry drum 18, viewed in the direction of the axis A, is arranged behind a rear wall 35 of the laundry drum 18 and connected to the laundry drum 18. In addition, the support star 34 is rotatably connected to the shaft 20, so that the laundry drum 18 can be rotated concentrically within the tub 16 connected by means of the carrying star 32. The support star 34 preferably comprises a plurality of unspecified support arms, for example, three support arms which are arranged in the direction of rotation about the axis A equidistant from each other, wherein the support arms extend radially to the axis A.

In Fig. 2, the carrier star 34 for receiving the laundry drum 18 is shown in a perspective view. The shaft 20 has already been connected to the support star 34 before an O-ring 36 and a bushing 38 are arranged on the shaft 20.

In Fig. 3, the connected to the shaft 20 supporting star 34 is shown in a side sectional view. The shaft 20 and the support star 34 form a shaft assembly 40. In the present case, the shaft 20 is connected to the carrier star 34 with an end region 42 having a toothing. A radial bearing 44 is mounted on a bearing 46 of the shaft 20. For sealing the radial bearing 44, a radial shaft sealing ring 50 is arranged in the region of a sealing point 48, which is located in the axial direction between the end region 42 and the bearing point 46 of the shaft 20. The shaft 20 is mounted by means of the radial bearing 44 on a bearing housing 52, wherein the radial shaft seal 50 is rotatably mounted on the bearing housing 52.

The already mentioned in connection with FIG. 2 bushing 28 is shown only schematically in the present case. As can be seen, the bush 28 surrounds the sealing point 48 of the shaft 20 on the outer peripheral side. The radial shaft sealing ring 50 rests on the outer circumference of the bushing 28, so that penetration of water and wash liquor into the radial bearing 44 can be prevented. The liner 28 is made of a corrosion-resistant material, such as a non-stainless steel, and made corrosion resistant by means of a surface treatment. Since the corrosion-resistant bushing 28 surrounds the shaft 20 in the region of the sealing point 48 on the outer peripheral side and the radial shaft sealing ring 50 sealingly rests on the bushing 28, it can be prevented that the shaft 20 is exposed to water and wash liquor. When forming the shaft assembly 40, the end portion 42 of the shaft 20 is connected to the supporting star 34 formed for receiving the laundry drum 18, wherein the radial bearing 44 is mounted on the bearing 46 of the shaft 20. To seal the radial bearing 44, the radial shaft sealing ring 50 is attached to the bearing housing 52 in the region of the sealing point 48 of the shaft 20. As already mentioned, the bushing 28 is made of a corrosion-resistant material and made corrosion-resistant by means of a surface treatment, before it is subsequently arranged at the sealing point 48 of the shaft 20, so that the radial shaft sealing ring 50 bears on the outer circumference of the bushing 28. As can be ensured by the shaft assembly 40 shown in Fig. 3 that no wash liquor and no other liquids can reach the shaft 20, the shaft 20 itself can be made of a relatively inexpensive corrosion-resistant material, for example, a non-stainless steel , A surface treatment to achieve a corrosion resistance of the shaft 20 can be omitted.

The liner 28 may be provided in the surface treatment, for example, with a chrome layer. Alternatively or additionally, it can also be provided that the bushing 28 is provided with a nickel and / or copper layer in the surface treatment. In particular, in a combination of application of a chromium layer and a nickel and / or copper layer, a particularly high surface finish on the bushing 28 and a particularly high corrosion resistance of the bushing 28 can be achieved. Alternatively or additionally, it is also possible for the bushing 28 to be nitrocarburized, whereby a nitrogen and carbon-enriched nitriding layer is formed on the bushing 28. First, the liner 28 can be made corrosion resistant by nitrocarburizing. On the other hand, the surface hardness of the bushing 28 can be significantly increased.

FIG. 4 shows a further embodiment of the shaft arrangement 40 in a schematic side sectional view. As can be seen in the case illustrated here, the support star 34 surrounds part of the bushing 28 on the outer peripheral side. The support star 34 can be made for example in a die-casting process. To connect the support star 34 with the end portion 42 of the shaft 20, the end portion 42 of the shaft during the manufacture of the support star 34, ie during the Die casting process, outer peripheral side by means of the supporting star 34 overmolded. In the embodiment of the shaft arrangement 40 shown in FIG. 4, a part of the bushing 28 arranged on the shaft 20 is also encapsulated in the course of the die-casting process by means of the support star 34 as well. During the production of the supporting star 34, this is thus connected to the end region 42 and a part of the bushing 28 in the same method step.

In Fig. 5, an alternative embodiment of the shaft assembly 40 is shown in a schematic side sectional view. In order to produce the embodiment shown here, first the end region 42 of the shaft 20 is encapsulated by means of the carrier star 34, as a result of which the end region 42 of the shaft 20 is connected to the carrier star 34. Only then is the already mentioned in connection with FIG. 2 O-ring 36 is slipped over the shaft 20 until it abuts the front side of the supporting star 34. In addition, the bushing 28, made corrosion-resistant by the surface treatment, is also slipped onto the shaft 20 with the carrier star 34 after the end region 42 of the shaft 20 has been overmoulded.

By the explained method for producing the shaft assembly 40 and by the described shaft assembly 40 can be ensured in a simple and cost-effective manner that the radial bearing 44 is protected from moisture. In addition, the shaft assembly 40 can be made particularly inexpensive, since neither the bushing 28 nor the shaft 20 must be made of a corrosion-resistant material. Nevertheless, due to the illustrated manufacturing method and the nature of the shaft assembly 40, the bush 28 and the shaft 20 can be prevented from rusting.

LIST OF REFERENCE NUMBERS

10 front loader washing machine

12 housing

14 vibration system

16 tubs

18 laundry drum

20 wave

22 Pulley

24 straps

26 engine

28 spring

30 dampers

32 carrying star

34 carrying star

35 rear wall

36 O-ring

38 bushing

40 shaft arrangement

42 end area

44 radial bearings

46 storage location

48 sealing point

50 radial shaft seal

52 bearing housing

A axis

X longitudinal direction z vertical direction

Claims

1 . Method for producing a shaft arrangement (40) for a domestic appliance (10) for the care of laundry items, in which an end region (42) of a shaft (20) is connected to a support structure (34) designed to receive a laundry drum (18) and a radial bearing ( 44) at a bearing point (46) of the shaft (20) and for sealing the radial bearing (44) in the region of between the end region (42) and the bearing point (46) arranged sealing point (48) of the shaft (20) a radial shaft seal ( 50) is arranged,

characterized in that

a bushing (28) made of a corrosion resistant material and made corrosion resistant by means of a surface treatment and then at the sealing point (48) of the shaft (20) is arranged.

2. The method according to claim 1,

characterized in that

the shaft (20) made of a corrosion-resistant material and without subjecting them to a surface treatment by means of which the corrosion resistance of the shaft (20) could be produced, is installed in the shaft assembly (40).

3. The method according to claim 1 or 2,

characterized in that

the bushing (28) is provided with a chrome layer during the surface treatment.

4. The method according to any one of the preceding claims,

characterized in that

the bushing (28) is provided in the surface treatment with a nickel and / or copper layer.

5. The method according to any one of the preceding claims,

characterized in that the bushing (28) is nitrocarburized during the surface treatment whereby a nitrogen and carbon enriched nitriding layer is formed on the bushing (28).

6. The method according to any one of the preceding claims,

characterized in that

the support structure (34) is produced by die-casting, wherein for connecting the support structure (34) to the end region (42) of the shaft (20), at least the end region (42) of the shaft (20) during the production of the support structure (34) on the outer peripheral side the support structure (34) is overmolded.

7. The method according to claim 6,

characterized in that

Moreover, a part of the shaft (20) arranged bushing (28) in the course of the die-casting process also by means of the support structure (34) is encapsulated.

8. The method according to claim 6,

characterized in that

the bush (28) is placed on the shaft (20) after the end portion (42) of the shaft (20) has been overmoulded by the support structure (34).

9. The method according to claim 8,

characterized in that

between the bushing (28) and the support structure (34), a sealing ring (36) on the shaft (20) is arranged.

10. Shaft arrangement (40) for a household appliance (10) for the care of laundry articles, in which an end region (42) of a shaft (20) is connected to a support structure (34) designed to receive a laundry drum (18) and a radial bearing (44) mounted on a bearing (46) of the shaft (20) and for sealing the radial bearing (44) in the region of between the end region (42) and the bearing point (46) arranged sealing point (48) of the shaft (20) a radial shaft seal (50) is arranged characterized in that

a bushing (28) made of a corrosion-resistant material and made corrosion-resistant by a surface treatment is disposed at the sealing point (48) of the shaft (20).

Household appliance (10) for the care of laundry items with a shaft arrangement (40) according to claim 10.

Domestic appliance (10) according to claim 1 1,

characterized in that

the household appliance (10) is a front-loading washing machine or top loading washing machine.