US20100206014A1

US20100206014A1 - Washing machine having a gasket

Info

Publication number: US20100206014A1
Application number: US12/679,926
Authority: US
Inventors: Uwe Ackermann; Serkan Koru; Turhan Mutlu
Original assignee: BSH Bosch und Siemens Hausgeraete GmbH
Current assignee: BSH Hausgeraete GmbH
Priority date: 2007-10-18
Filing date: 2008-10-09
Publication date: 2010-08-19
Also published as: EP2207928A1; WO2009050095A1; CN101827971A; EA201070469A1; TR200707121A2

Abstract

A washing machine includes a housing with a front panel defining a front opening, a tub defining a tub opening, and a drum in the tub rotatable on a rotation axis and defining a drum opening. The drum is connected to a motor defining a rotation direction. The tub opening and the drum opening define a gap enabling drum rotation while the motor is rotating the drum. The washing machine further includes a ring-shaped gasket providing a substantially waterproof seal between the front panel and the tub and including a front rim engaging the front opening, a rear rim engaging the tub opening, and a collar having a first end adjacent the rear rim and projecting radially inwardly beyond the gap to a second end. A collar thickness between the first end and the second end is not uniform around the gasket.

Description

The present invention relates to a washing machine comprising a housing having a front panel in which a front opening is formed for loading and retrieving laundry, the housing is forming exterior of the washing machine, a tub, disposed behind the front panel, secured within the housing, having a tub opening for communicating with the front opening, a drum rotatably disposed within the tub on a rotation axis, having a drum opening substantially aligned with the tub opening, being connected with a motor defining a rotation direction, and a gap enabling drum rotation while the motor is rotating the drum formed between the tub entrance and drum entrance, and a ring-shaped gasket forming a substantially waterproof seal between the front panel and the tub and including a front rim engaging the front opening, a rear rim engaging the tub opening, and a collar having a first end adjacent the rear rim and projecting radially inwardly beyond the gap to a second end.
Generally, a drum type washing machine—that may be embodied in a washing/drying machine as well—includes a cabinet forming an exterior of the washing machine and has a forward opening, formed in a front panel of the cabinet for loading and retrieving laundry via a door. A tub fixedly installed within the cabinet has an entrance for communicating with the forward opening of the front panel. A drum rotatably installed within the tub and provided with a multitude of perforations for water to pass from the tub to the interior of the drum and back, has a cylindrical shape with an entrance at its front end to communicate with the tub entrance. A gasket having an essentially annular shape is provided between the cabinet and the tub for preventing water leakage while the door is closed. To achieve leakage prevention, the gasket includes a front rim coupled to the front panel of the cabinet and a rear rim coupled to the entrance of the tub, to thereby close the gap between cabinet and tub. The rear rim generally includes a uniformly shaped collar projecting radially inwardly to fill the gap between the tub and the drum to resist and block passage or sticking of the laundry between the tub and the drum.
As the drum rotates within the tub under a drive force of a motor, various parameters, such as, imbalanced load of the laundry, vibration of the drum and minor asymmetrical differences on circular shape of the drum cause dynamic deflection based on a complex movement of the drum as an axial movement combined with an eccentric rotation.
Accordingly, it is an object of the present invention to mitigate a varying gap between the tub and the drum while the washing machine is in operation.
Additional aspects and/or advantages of the invention will be set forth in part in the description which follows and will be apparent from the description, or may be learned by practice of the invention.
It is an aspect of the present invention to provide a washing machine comprising; a housing having a front panel in which a front opening is formed for loading and retrieving laundry, the housing is forming exterior of the washing machine; a tub, disposed behind the front panel, secured within the housing, having a tub opening for communicating with the forward opening; a drum rotatably disposed within the tub on a rotation axis, having a drum opening substantially aligned with the tub opening, being connected with a motor defining a rotation direction, and a gap, enabling drum rotation while the motor is rotating the drum, formed between the tub entrance and drum entrance. A ring-shaped gasket forms a substantially waterproof seal between the front panel and the tub, and the tub includes a front rim engaging the front opening and a rear rim engaging the tub opening. A collar has a first end adjacent the rear rim and projects radially inwardly beyond the gap to a second end. A collar thickness between the first end and the second end is non-uniform around the gasket.
In certain preferred aspects and in certain preferred constructions, the collar has first and second arcuate sections along the ring-shaped gasket, the collar thickness in the first section is greater and the collar thickness in the second section.
In certain preferred aspects and in certain preferred constructions, the first section is disposed at least partially below the rotation axis and the second section is disposed at least partially above the rotation axis.
In certain preferred aspects and in certain preferred constructions, the first section is disposed at least partially above the rotation axis and the second section is disposed at least partially below the rotation axis.
In certain preferred aspects and in certain preferred constructions, the first section has a first section length and the second section has a second section length, and wherein the second section length is greater than the first section length.
In certain preferred aspects and in certain preferred constructions, the inventive washing machine further includes a shock absorber, disposed between the front rim and rear rim and having an elongated bent shape between the front rim and the rear rim to attenuate vibration from the tub to the housing.
In certain preferred aspects and in certain preferred constructions, the said collar keeps the laundry from the gap while the motor is in operation. In certain preferred aspects and in certain preferred constructions, the second section is disposed at least partly following the second section in a clockwise direction starting from a bottom of the collar.
In certain preferred aspects and in certain preferred constructions the collar of the inventive washing machine further comprises a substantially circular perimeter, having a center eccentric to the rotation axis when the motor is inactive and formed by adjacent inner peripherals of the first section and the second section. In certain preferred aspects and in certain preferred constructions, the circular perimeter has a substantially concentric center with the rotation axis, while the motor is in operation.
In certain preferred aspects and in certain preferred constructions; the collar has a first end adjacent the rear rim and projecting radially inwardly beyond the gap to a second end, wherein a collar distance from the first end to the second end is non-uniform around the gasket.
In certain preferred aspects and in certain preferred constructions; both the collar distance and the collar thickness, between the first end and the second end are non-uniform.

These and/or other aspects and advantages of the invention will become apparent and are more readily appreciated from the following description of preferred embodiments taken in conjunction with the accompanying drawings in which:

FIG. 1 a illustrates a perspective view of a washing machine having a gasket in accordance with an embodiment of the invention;

FIG. 1 b illustrates a front view of an embodiment of the gasket used in a washing machine;

FIG. 2 a is a cross-sectional view of the gasket depicted in FIG. 1 b taken along the line AA;

FIG. 2 b is a cross-sectional view of the gasket depicted in FIG. 1 b taken along the line BB;

FIG. 2 c is a cross-sectional view of the gasket depicted in FIG. 1 b taken along the line CC;

FIG. 2 d is a cross-sectional view of the gasket depicted in FIG. 1 b taken along the line DD;

FIG. 2 e is a cross-sectional view of the gasket depicted in FIG. 1 b taken along the line EE;

FIG. 2 f is a cross-sectional view of the gasket depicted in FIG. 1 b taken along the line FF;

FIG. 3 is an enlarged side view of a portion of gasket and showing drum positions while rotating;

FIG. 4 is an enlarged side view of a portion of gasket showing the axial and radial changes on the cross-section of a gasket.

FIG. 5 is a complete length graphic of the washing machine at each clock position of the drum rotating at 1200 or 800 rpm;

REFERENCE NUMERALS

10 Housing 46 Collar
12 Front panel 47 Groove
14 Front opening 48 Rear rim
16 Door 50 Motor
20 Tub 60 Suspension means
22 Gap α Sensor angles
26 Tub opening X1 First axial distance
30 Drum X2 Second axial distance
32 Lifter Y1 First radial distance
34 Perforations Y2 Second radial distance
36 Drum opening R Radial difference
40 Front rim L Axial difference
42 Front rim
44 Shock absorber
Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Throughout the drawings, like elements are indicated using the same or similar reference numerals wherever possible.
Referring to FIG. 1, a drum type washing machine according to the present invention comprises; a housing 10 forming an exterior of the washing machine and having a circular forward opening 14, formed in a front panel 12 of the housing 10, for loading and retrieving laundry via a door 16. A tub 20, disposed behind and suspended within the housing 10, having a tub opening 26 for communicating with the front opening 14 of front panel 12; and a drum 30, rotatably installed within the tub 20 and provided with a multitude of perforations 34 to allow water to pass from the tub 20 to the drum 30, having a cylindrical shape with a drum opening 36 at its front end to communicate with the tub openings 26.
A motor 50 such as an induction or BLDC motor for rotating the drum 30 and including rotational shaft centrally coupled to the rear of the drum 30, is installed behind the tub 20 and rotates the drum 30 forward and reversely according to the motor's rotational direction. At least one lifter 32 is provided to an inner wall of the drum 30 to assist the washing action by repeatedly lifting the laundry to a predetermined height as the drum 30 is rotated and then allowing the lifted laundry to fall from the predetermined height.
To attenuate vibration generated during operation of the drum-type washing machine, the tub 20 is supported by a suspension means 60, including springs, dampers etc., disposed above and below the tub 20.
A drum-type washing machine as described above is provided with a gasket 40 as shown in FIG. 1 b. The gasket 40 has a ring shape, is provided between the housing 10 and the tub 20 installed behind the front panel 12, essentially connecting the tub opening 26 to the front opening 14. To prevent water leakage while the door 16 is closed, the gasket 40 includes a front rim 42 having u-shaped cross section which is bent outwardly to couple the front opening 14. The gasket 40 further includes a rear rim 48 coupled to the tub opening 26 by means of a groove 47 which is formed at rear rim 48. A hollow shock absorber 44 having S-shaped cross-section is disposed between the front rim 42 and the rear rim 48. A collar 46 on the rear rim 48 is radially inwardly extending beyond a gap 22 between the tub opening 26 and drum opening 36 which are essentially aligned. Collar 46 thickness differs around the gasket 40.
To perform washing action the motor 50 provides rotational movement on the drum 30 wherein a laundry load and lifters 32 force the drum 30 to present an imbalance due to a dynamic bending moment; consequently, a vibration occurs. Vibration causes radial and axial movement of the drum 30 within the tub 20. The amplitude of movement is bound to different parameters of the washing machine such as cycle time, speed or weight of the laundry. Under certain circumstances axial movement causes the drum 30 to hit some portions of the collar 46 which is stationary between the tub 20 and drum 30. In order to define such a problem a test has been conducted to define axial distance of a drum 30 in predetermined positions and rotational speed parameters.
Various collar 46 thicknesses are provided on the rear rim 48 to prevent at the one hand drum 30 friction with the collar 46 and at the other hand to increase gap 22 distances.
FIGS. 1 b, 2 a, 2 b, 2 c, 2 d and 2 e show cross-sections of the same gasket 40 wherein the collar 46 thicknesses vary as shown in Table 1 below.

TABLE 1

Variable collar thickness of rear rim (mm) at clock positions

	a	b-b′	d-d′	c-c′	e-e′	f-f′

10.82	8.69	9.2	9.8	10.82	10.82
	10.48	10.18	9.69	9.96	9.69

Test results related to total length of the drum 30 and tub 20 at 1200 rpm and 800 rpm are shown in Table 2 below. It can be derived that total difference between maximum and minimum lengths at predetermined clock positions on drum 30 is equal to axial distances of the drum 30 movement with respect to the housing 10 which are 1.69 mm and 1.79 mm respectively.
As seen on FIG. 5 both graphics indicate minimum lengths which means a hit of drum 30 to collar 46 is possible at 5 to 9 o'clock positions. At the other hand average total lengths are 396.85 mm and 395.88 mm respectively.

TABLE 2

Total length at the drum of 1200 rpm and 800 rpm washing
machine at clock positions (mm)

1200 rpm

800 rpm

Position	Total Length		Total Length	Collar
(Hours)	(mm)	Position	(mm)	Thickness

12	a	397.23	12	396.29	10.82
1	b	397.01	1	395.99	8.69
2	d	397.01	2	395.91	9.2
3	c	396.95	3	395.88	9.8
4	e	397.11	4	395.91	10.82
5	f	396.99	5	395.86	10.82
6	a′	396.41	6	395.44	n/a
7	b′	395.86	7	395.05	10.48
8	c′	396.09	8	395.18	10.18
9	d′	396.82	9	395.96	9.69
10	e′	397.55	10	396.84	9.96
11	f′	397.54	11	396.67	9.69

Inverse proportion between collar 46 thicknesses and total length of the drum 30 can be derived from the Table 2 wherein the collar 46 thickness is decreased while total length is becoming higher. This is also means that the collar 46 thickness is decreasing at clock positions 12 to 1 hour afterwards increasing until 4 and 5 hours, again decreasing 9 hours and increasing until 10 hours then decreasing again until 12 hours. This movement is the x-y symmetrical of the graphic seen on FIG. 5 which discloses total length of the drum 30 and tub 20 on 1200 rpm and 800 rpm washing machines.
FIG. 3 shows an enlarged view of upper parts of the gasket 40 and drum 30 during the operation of the washing machine at two different rotational speeds which are 800 rpm and 1200 rpm. Due to the vibration and other effective forces, complex movement of the drum 30 causes a first axial distance x1 relative to the stationary gasket 40. In case of the 1200 rpm rotational speed of the drum 30 or lesser laundry weight for the same washing machine, a second axial distance x2 which cause bigger gap 22 between the drum 30 and the gasket 40 occurs.
In FIG. 4 it is shown that axial difference L of the cross-section of the gasket 40 which is calculated by an equation of a fixed gap 22 length and total length of the drum 30, first x1 or second axial distance x2 and the tub 20. In each clock position of the gasket 40, collar 46 length including axial difference L value, provides the predefined gap 22 between the collar 46 and the drum 30 having first axial distance x1. The gap 22 length is defined not only to prevent friction but also to obstruct laundry. Likewise, a radial difference R varying on cross-sections at each clock positions of the gasket 40 provides the gap 22 between the collar 46 and peripheral of the tub opening 26 wherein a first axial distance y1 at 800 rpm or a second radial distance at 1200 rpm occurs. Radial difference R provides predefined gap length at first y1 and second radial distances y2 and also overall positions of the drum 30.

Claims

1-12. (canceled)

13. A washing machine comprising:

a housing with a front panel defining a front opening for loading and retrieving laundry, the housing forming an exterior of the washing machine;

a tub behind the front panel and secured within the housing defining a tub opening for communicating with the front opening;

a drum in the tub rotatable on a rotation axis and defining a drum opening substantially aligned with the tub opening;

a motor connected to the drum and defining a rotation direction, wherein the tub opening and the drum opening define a gap enabling drum rotation while the motor rotates the drum; and

a ring-shaped gasket providing a substantially waterproof seal between the front panel and the tub and including a front rim engaging the front opening, a rear rim engaging the tub opening, and a collar having a first end adjacent the rear rim and projecting radially inwardly beyond the gap to a second end, wherein a collar thickness between the first end and the second end is not uniform around the gasket.

14. The washing machine of claim 13, further comprising a shock absorber between the front rim and rear rim and having an elongated bent shape between the front rim and the rear rim to attenuate vibration from the tub to the housing.

15. The washing machine of claim 13, wherein said collar keeps the laundry from the gap while the motor is in operation.

16. The washing machine of claim 13, wherein the collar has first and second arcuate sections along the ring-shaped gasket, the collar thickness in the first section is greater than the collar thickness in the second section.

17. The washing machine of claim 16, wherein the first section is partially below the rotation axis and the second section is partially above the rotation axis.

18. The washing machine of claim 16, wherein the first section is partially above the rotation axis and the second section is partially below the rotation axis.

19. The washing machine of claim 16, wherein the first section has a first section length and the second section has a second section length greater than the first section length.

20. The washing machine of claim 16, wherein the second section is partly follows the first section in a clockwise direction starting from a bottom of the collar.

21. The washing machine of claim 16, wherein adjacent inner peripherals of the first section and the second section of the collar defines a substantially circular perimeter with a center eccentric to the rotation axis when the motor is inactive.

22. The washing machine of claim 16, wherein the circular perimeter has a substantially concentric center with the rotation axis while the motor is in operation.