WO2018202549A1

WO2018202549A1 - A dynamic vibration damper and the washing machine using the same

Info

Publication number: WO2018202549A1
Application number: PCT/EP2018/060776
Authority: WO
Inventors: Ahmet Ali Uslu; Erkan Tarakci; Egemen TINAR; Cetin YILMAZ; Salih YILDIRIM
Original assignee: Arcelik Anonim Sirketi
Priority date: 2017-05-05
Filing date: 2018-04-26
Publication date: 2018-11-08
Also published as: TR201706613A3

Abstract

The present invention relates to a dynamic vibration damper (1) being suitable for use in a washing machine, having a body and a tub (6) provided in the body, in which washing process is performed and oscillating during operation, stabilizing the washing machine body in high amplitude vibrations occurring on the tub (6), and a washing machine in which the dynamic vibration damper (1) is used.

Description

A DYNAMIC VIBRATION DAMPER AND THE WASHING MACHINE USING THE SAME

The present invention relates to a dynamic vibration damper stabilizing a washing machine by vibrations of high amplitudes generated in a drive group, and a washing machine in which said dynamic vibration damper is used.

Vibrations occurring in a washing machine and its lower members are on top of the list of circumstances which should be avoided. Vibrations generated depending on random dynamic load distributions occurring in a drive group while the washing machine is in operating condition, can reach high amplitudes. Therefore, it is required to eliminate the instability in a washing machine or to contain the high amplitude vibrations generated due to instability, by damping such vibrations. Keeping such undesired vibrations within appropriate limits directly effects the noise level and useful lifetime parameters and enhance the quality perception of the washing machine on the customer.

Dynamic vibration dampers are secondary mechanical vibration systems utilized for reducing and thereby containing the vibration amplitudes of vibrating mechanical structures, and used by being mounted on main vibration systems. Such systems merely consist of mass, spring and/or damping member. They are very suitable to avoid the resonation of the main system. Two degree of freedom system is generated when these are coupled to a system of single degree of freedom. Single degree of freedom systems have one, and the new generated system has two natural frequencies. One of said frequencies is higher and the other is smaller than the natural frequency of the previous system before using the dynamic vibration damper.

Dynamic vibration dampers can be used for solving vibration problems of the systems driven by a drive of a frequency proximate to its natural frequency. For example, if a drive frequency applied to a system overlaps with one of the natural frequencies of the system, the system resonates in said operation frequency and displacements of very high amplitudes are observed. When one dynamic vibration damper is introduced to the system, high amplitude vibrations are observed in the dynamic vibration damper. The primary system is thus prevented from resonating.

Dynamic vibration dampers placed between body and drive group are used in the state of the art for reducing the vibrations generated in the body of a washing machine. By this, the vibrations forming as a result of the drive group's operation effect the body after being damped.

State of the art patent document no. CA20082645978 discloses a washing machine comprising a housing, a tub provided in the housing, a laundry washing drum rotatably mounted to the tub, and a vibration preventing device provided in the tub. The vibration preventing device described in said document comprises a damping system comprising a spring and a weight, and is used for damping vibrations whose resonance value is between two determined limit values.

State of the art patent document no. EP2011912 discloses a dynamic vibration damper for washing machines. The vibration damper comprises a weight, elastic members (spring) supporting said weight, and a guide for delimiting motions of the weight. In said document, vibrations in a single axis are damped as the weight used to stabilize vibrations is capable of moving in a single direction.

State of the art patent document no. WO2008056953 discloses reducing body vibrations of a washing machine by a dynamic vibration damper connected to the attachment point of the suspension spring of the washing machine. Said dynamic vibration damper consists of a rod and a weight joined to the end portion of the rod, and is joined to the suspension spring attachment point and damps the vibrations at said point.

State of the art patent document no. US2006117812 discloses reducing body vibrations of a washing machine by a dynamic vibration damper connected to the spring and the upper panels of the washing machine. The vibrations reaching on the body are damped by a weight connected to the middle or the end portion of an elastic member (spring, rubber, composite panel, etc.).

The present invention relates to a dynamic vibration damper used in a washing machine in order to eliminate the above-mentioned disadvantages and to bring new advantages to the related technical field, and its implementation.

Within the scope of the invention, a novel dynamic vibration damper has been contemplated enabling reducing the noise and the vibrations occurring in spinning revolutions in a washing machine, and the displacements occurring in this step during operation of the drive group of the washing machine, have been reduced. The invention contains many advantages compared to documents briefing the state of the prior art.

It is identified that there is a reduction in forces applied on the springs and the vibration dampers in the spinning step of a washing machine.
Since reduction of the forces applied on the spring and the vibration dampers also reduces the forces transmitted to the body of the washing machine, the noise levels generated due to body vibrations in the washing machine are also reduced.
The nonstable loads occurring in the washing machine were damped independently of their positions and sizes, and the drive group displacements are thus significantly reduced. Consequently, the sound power level scattering generated due to randomly forming instability is prevented, reducing the declared sound level of the washing machine.
In case of occurring high levels of instability in a washing machine, if the instability was not eliminated by additional movements, then laundry washing process would be terminated without performing the spinning step. Now, washing process is completed in a more consistent manner as a result of damping the unstable loads.
Instability occurs more frequently when the washing machine is operated without being loaded in full capacity. It is observed that using the dynamic vibration damper also provides advantage to the consistency of washing process in half loading cases as the drive group vibrations are minimized.

The aim of the present invention is to realize a dynamic vibration damper enabling effectively damping vibrations.

In order to realize all aims mentioned above and those that will appear from the detailed disclosure below, the present invention relates to a dynamic vibration damper with adjustable operational frequency, stabilizing a washing machine body in high amplitude vibrations forming in a drive group, and its implementation. Said invention comprises at least one elastic member of a rod shape with annular cross-section, enabling springing in vertical and horizontal axes, and a front balancing mass and a rear balancing mass enabling damping vibration amplitudes by connecting to at least one of the end portions of the elastic member.

A preferred embodiment of the invention is the elastic member being fixed such that an end portion of the elastic member is joined to the front balancing mass and the other end portion of the elastic member is joined to the rear balancing member by means of abutments so as to have the middle of the elastic member on the middle of the washing machine tub, and the number of the elastic members being increased so as to have four of them around the washing machine tub.

Another preferred embodiment of the invention is joining by means of abutments three elastic members to the front portion of the washing machine tub and three elastic members to the back portion of the washing machine tub, and the other end of the elastic members joined to the front of the washing machine tub being configured to be joined to the rear balancing masses, and the elastic members joined to the back portion of the washing machine tub being configured to be joined to the front balancing masses.

The dynamic vibration damper realized to achieve the aims of the present invention is illustrated in the accompanying drawings, wherein:

Figure 1 is a view of the dynamic vibration damper of an embodiment of the invention, on the drive group.

Figure 2 is a view of the dynamic vibration damper of another embodiment of the invention, on the drive group.

Figure 3 is a side view of the dynamic vibration damper of another embodiment of the invention, on the drive group.

The elements in the figures are numbered individually and the correspondence of these numbers are given hereinafter.

Dynamic vibration damper
Elastic member
Abutment
Rear balancing mass
Front balancing mass
Tub
Reinforcement member

In this detailed disclosure, the novelty of the invention is disclosed by way of non-limitative example only to provide a better understanding of the subject matter. Dynamic vibration damper (1) in a washing machine and the elements it comprises are disclosed.

The dynamic vibration damper (1) is suitable for use in a washing machine having a body, and a tub (6) in which washing process is performed, provided in the body and oscillating during operation, and stabilizes the washing machine body in high amplitude vibrations occurring on the tub (6).

The dynamic vibration damper (1) of the invention comprises at least one rod-shaped elastic member (2) attached on the tub (6) at least at one point, enabling springing in vertical and horizontal axes, and at least one front balancing mass (5) and at least one rear balancing mass (4) joined to at least one of the end portions of the elastic member (2) so as to damp vibration amplitudes. Dynamic vibration damper (1) is designed according to the frequency in which it is desired to operate by modifying its rigidity and mass. The operational frequency of the dynamic vibration damper (1) is predetermined. For this, the springing rigidity of the elastic member (2) is determined by modifying its thickness, length, cross-sectional properties and number, and the mass of the system is selected by modifying the weights of the front and rear balancing masses (5,4) to which the elastic member (2) is joined.

In an embodiment of the invention, the elastic member (2) has an annular cross-section. The elastic member (2) has an elastic structure in horizontal and vertical directions since it has an elongated rod shape with an annular cross-section. The pertinacities of the elastic members (2) in horizontal and vertical directions being identical enables vibration damping process to be performed successfully in both directions.

In another embodiment of the invention, the dynamic vibration damper (1) comprises abutments (3) containing grooves with semicircular cross-sections, enabling the elastic member (2) to be mounted on the tub (6), the front balancing mass (5) and/or the rear balancing mass (4). Abutments (3) are provided on the middle points on the tub (6) and at the corresponding points on the front and the rear balancing masses (5,4). The abutments (3) through which the elastic members (2) pass, are fixed to the tub (6). The abutments (3) acting as coupling members in the dynamic vibration damper (1), have a flat metal body shape comprising grooves adapted to the shape of the elastic member (2).

In another embodiment of the invention, an end portion of the elastic member (2) is attached to the front balancing mass (5) and the other end of the elastic member (2) is attached to the rear balancing mass (4) such that the middle of the elastic member (2) is attached to the middle of the tub (6). Said embodiment of the dynamic vibration damper (1) is shown with reference to Figure 1. One end of the elastic member (2) is joined to the rear balancing mass (4) and the other end is joined to the front balancing mass (5). The balancing masses (5,4) and the washing machine tub (6) are joined to each other by means of the elastic member (2).

In another embodiment of the invention, four dynamic vibration dampers (1) are provided around the tub (6). The connections of the dynamic vibration damper (1) are of utmost importance in terms of controlling the tensions forming on the abutment (3) points and the elastic member (2), and in terms of strengths of the tub (6) and the dynamic vibration damper (1). Therefore and in terms of the ability of damping vibrations in all directions, the dynamic vibration damper (1) is constructed such that around the tub (6) there are four of the damping systems built by the elastic member (2) between the front and the rear balancing masses (5,4) and the tub (6), and positioned with symmetrical repetitions so as to stabilize the forces forming in the tub (6).

In another embodiment of the invention, three elastic members (2) are joined to the front portion of the tub (6), and three elastic members (2) are joined to the back portion of the tub (6), and the other end of the elastic members (2) joined to the front portion of the tub (6) are joined to the rear balancing mass (4), and the other ends of the elastic members (2) joined to the back portion of the tub (6) are joined to the front balancing mass (5). Another configuration of the invention is shown with reference to Figure 2 and Figure 3. A total of six abutments (3) are joined to the tub (6). Three abutment (3) points placed on the front section of the washing machine, and elastic members (2) with annular cross-sections, passing through said abutments (3) are used. The elastic member (2) joined to the abutments (3) disposed in the front section, are joined at their end points to the rear balancing mass (4). In addition, there are three abutment (3) points on the back section of the washing machine and an elastic member (2) passing through said abutments (3). The elastic members (2) joined to the abutments (3) disposed in the back section, are joined at their end points to the front balancing mass (5). The abutment (3) points being on the front and the back portions of the washing machine tub (6), allows extending the lengths of the elastic members (2) along the axis of the washing machine tub (6). Thus, the tensions on the elastic member (2) are significantly reduced.

In another embodiment of the invention, a plurality of abutments (3) are fixed to each other so as to be on top of each other, thereby allowing a desired number of elastic members (2) to be mounted thereon. The flush limit conditions are met for each elastic member (2) by tightening the elastic members (2) to the grooves evenly by placing two abutments (3) on top of each other, and tightening them at their center by a bolt and washer. By this, the abutments (3) can be placed on top of each other and a desired number of elastic members (2) can be fixed on them.

In another embodiment of the invention, the dynamic vibration damper (1) comprises a reinforcement member (7) riveted between the abutment (3) and the washing machine tub (6), enabling reducing deformation and having in its middle portion an extrusion whose center is perforated allowing the abutments (3) to be attached by bolts. The reinforcement member (7) is provided between the tub (6) and four abutments (3) disposed on the tub (6). High amount of tension and deformation occurs on the abutment (3) connection points disposed on the tub (6). In order to reduce the tensions caused by the loads applied on the tub (6), a reinforcement member (7) is placed between an abutment (3) and the tub (6), with a larger surface area than an abutment (3). An extrusion having a bolt hole, is provided on the upper middle portion of the reinforcement member (7), and the member is joined to the tub (6) by being riveted from below.

In another embodiment of the invention, the wall thickness is increased at the portions of the tub (6) where the reinforcement member (7) is riveted. Deformations occurring due to forces applied on the reinforcement member (7) connection points are reduced by increasing the plastic wall thickness of the tub (6) at the points where the reinforcement member (7) is riveted to the tub (6).

In another embodiment of the invention, the elastic member (2) is made of metal material. The elastic member (2) should also be resistant against the tensions applied thereon. Therefore, the elastic member (2) being made of metal materials increases the operational effectiveness of the dynamic vibration damper (1). In a preferred version of this embodiment, the elastic member (2) is made of steel material. Ideal springing performance is obtained without compromising the durability of the elastic member (2) thanks to the elasticity of steel material.

The invention is tested by being configured to damp high amplitude vibrations occurring during operation of the washing machine in 1000 rev/min (in spinning revolutions). The natural frequency of the dynamic vibration damper (1) is set to be 16.7 Hz, formed by selecting appropriate diameters and lengths of elastic member (2) and weights of front and rear balancing masses (5,4) This is first obtained by theoretical calculations, and then verified by numerical analysis software.

It is aimed for the dynamic vibration damper (1) to resonate and damp the vibrations generated on the drive group once the washing machine reaches the spinning revolutions (1000 rev/min), and reductions in displacements of the drive group were expected. The conducted tests and measurements on a physical prototype displayed that tub (6) displacements were significantly reduced when the dynamic vibration damper (1) was introduced to the drive group of the washing machine. The tub (6) displacement values were observed to drop to approximately one fifth of the original values for all varying unstable load conditions. In addition, the presence of the front and rear balancing masses (5,4) used to stabilize the generated vibrations, enable the dynamic vibration damper (1) to operate independently from the position of instability. The front balancing mass (5) operates more when the unstable load revolving in the tub (6) is closer to the front, and the rear balancing mass (4) operates more when the unstable load is closer to the back of the tub (6). In case there are unstable loads in diagonal position in front and back of the tub (6), then the front and the rear balancing masses (5,4) reduce the vibration amplitudes by operating in reverse phase.

The implementation method of the dynamic vibration damper (1) stabilizing a washing machine by high amplitude vibrations occurring in the drive group, comprises the processing steps of:

Preconfiguring the operational frequency of the dynamic damping system to a desired value by modifying the cross-section, length and weight parameters of the elastic member (2), the front balancing mass (5) and the rear balancing mass (4),
Building a dynamic damping system by providing the mechanical connection between the tub (6) and the front balancing mass (5) and/or the rear balancing mass (4) by means of the elastic member (2), and
Repeating the built dynamic vibration damping system around the washing machine tub (6) so as to stabilize the loads forming in the washing machine tub (6).

The washing machine of the invention comprises the above-disclosed dynamic vibration damper (1).

In the invention, vibrations are damped by means of the elastic member fixed between weights and the tub, and the pertinacities of the elastic member in horizontal and vertical directions are identical thanks to its annular cross-section, enabling performance of the vibration damping process in both directions unlike the dynamic vibration dampers of the prior art.

Claims

A dynamic vibration damper (1) suitable for use in a washing machine having a body, and a tub (6) in which washing process is performed, provided in the body, oscillating during operation; stabilizing the washing machine body in high amplitude vibrations, characterized in that the dynamic vibration damper (1) comprises at least one rod-shaped elastic member (2) attached on the tub (6) at least one point, enabling springing in vertical and horizontal axes, and at least one front balancing mass (5) and at least one rear balancing mass (4) to at least one of which the end portions of the elastic member (2) is joined so as to damp vibration amplitudes.
Dynamic vibration damper (1) according to claim 1, characterized in that the elastic member (2) has an annular cross-section.
Dynamic vibration damper (1) according to claim 1 or claim 2, characterized in that, it comprises abutments (3) having grooves with semicircular cross-sections enabling the elastic member (2) to be mounted on the tub (6), the front balancing mass (5) and/or the rear balancing mass (4).
Dynamic vibration damper (1) according to any one of the preceding claims, characterized in that, an end portion of the elastic member (2) is attached to the front balancing mass (5) and the other end of the elastic member (2) is attached to the rear balancing mass (4) such that the middle of the elastic member (2) is attached to the middle of the tub (6).
Dynamic vibration damper (1) according to claim 4, characterized in that, there are four of dynamic vibration dampers (1) around the tub (6).
Dynamic vibration damper (1) according to claims 1 to 3, characterized in that, three elastic members (2) are joined to the front portion of the tub (6), and three elastic members (2) are joined to the back portion of the tub (6), and the other end of the elastic members (2) joined to the front portion of the tub (6) are joined to the rear balancing mass (4), and the other ends of the elastic members (2) joined to the back portion of the tub (6) are joined to the front balancing mass (5).
Dynamic vibration damper (1) according to claim 3, characterized in that, a plurality of abutments (3) are fixed to each other so as to be on top of each other, so as to allow a desired number of elastic members (2) to be mounted thereon.
Dynamic vibration damper (1) according to any one of claim 3 or claim 7, characterized in that it further comprises a reinforcement member (7) riveted between an abutment (3) and the washing machine tub (6), enabling reducing deformation and having in its middle portion an extrusion whose center is perforated allowing the abutments (3) to be attached by bolts.
Dynamic vibration damper (1) according to claim 8, characterized in that the wall thickness of the portions of the tub (6) where the reinforcement member (7) is riveted, are increased.
Dynamic vibration damper (1) according to any one of the preceding claims, characterized in that the elastic member (2) is made of metal material.
Dynamic vibration damper (1) according to claim 10, characterized in that the elastic member (2) is made of steel material.
Method of implementation of a dynamic vibration damper (1) according to the preceding claims, stabilizing the body of a washing machine by high amplitude vibrations occurring on the tub (6), characterized in that the method comprises the processing steps of:

- Preconfiguring the operational frequency of the dynamic damping system to a desired value by modifying the cross-section, length and weight parameters of the elastic member (2), the front balancing mass (5) and the rear balancing mass (4),

- Obtaining a dynamic damping system by providing the mechanical connection between the washing machine tub (6) and the front balancing mass (5) and/or the rear balancing mass (4) by means of the elastic member (2), and

- Repeating the obtained dynamic damping system around the washing machine tub (6) so as to stabilize the loads in the washing machine tub (6).
A washing machine, characterized in that, it has a dynamic vibration damper (1) according to any one of the preceding claims.