WO2003074900A1

WO2003074900A1 - A frictional vibration damper

Info

Publication number: WO2003074900A1
Application number: PCT/TR2002/000008
Authority: WO
Inventors: Adil Kaniöz
Original assignee: Kanioez Adil
Priority date: 2002-03-04
Filing date: 2002-03-04
Publication date: 2003-09-12
Also published as: AU2002248130A1

Abstract

This invention relates to a frictional vibration damper, especially used in washing machines with a spinning drum. The damper of the invention comprises two shette metals (9) bent and assembled together to form a piston rod (3), in order to facilitate the manufacture, and overcome the typical heat problem encountered by dampers.

Description

A FRICTIONAL VIBRATION DAMPER

This invention relates particularly to a frictional vibration damper used especially in washing machines having a rotating drum.

The frictional dampers used in washing machines are, in general, elements that damp out the vibrations caused by the unbalance at the beginning or end of the rotation, or acceleration and/or deceleration of the machine drum. These frictional dampers function by means of the compression force created by one or two compression elements compressed between two telescopic pipes or similar parts. The referred dampers can be classified into two groups based on the operating positions of the frictional elements.

First group functions by the friction of the outer surface of a ring-like piece formed by a cellular sponge-like plastic material to the inner surface of a pipe. The second group is composed of dampers wherein the inner surface of the said annular friction ring is in friction with the outer surface of a pipe. In both groups of dampers, incorporation of pipes lead to manufacturing difficulties and high costs. Moreover, heat generated by friction decreases performance over time.

Prior art reference WO99/505568 discloses a friction vibration damper wherein a friction element is placed in between two telescopic pipes.

The object of the present invention is to provide a friction damper of the latter type, which comprises two sheet metals bent and combined to form a pipe in order to facilitate manufacture and which thereby overcomes the typical heat problem encountered by dampers, as well as reducing the manufacturing costs and increasing the productivity.

In the following description, the frictional vibration damper, realised in order to attain the objectives of this invention has been described with reference to the attached drawings, wherein: Figure la is the horizontal cross section view of the frictional vibration damper;

Figure lb is the vertical cross section view of the frictional vibration damper;

Figure 2 is side view of the assembled piston rod;

Figure 3 a is the cross sectional top view of the plastic carrier piece;

Figure 3b is the side view of the plastic carrier piece;

Figure 3 c is the front view of the plastic carrier piece;

Figure 4a is the side view of the steel sheet bent into a semi-cylinder;

Figure 4b is the front view of the steel sheet bent into a semi-cylinder;

Figure 5a is the cross section view showing the two steel sheets bent into a semi-cylinder;

Figure 5b is the side view of the two steel sheets bent into a semi-cylinder;

Figure 6a is the cross section view of the coupling ring;

Figure 6b is the top view of the coupling ring.

The components shown in the drawings have been given separate numerals as shown below:

1. Frictional vibration damper

2. Tubular body 3. Plunger piston rod

4. Friction element

5. B all-and-socket j oint

6. Head bearing

7. Steel bush 8. Rubber plastic bush

9. Steel semi-cylinder

10. Carrier piece

11. Coupling ring 12. Claw of the tubular body

13. First graduation of the tubular body

14. Second graduation of the tubular body

15. Locking segment

16. Claw of the locking segment 17. Slot

18. Cooling fm

19. H profile

20. Support ring

21. Rectangular ventilation opening 22. Ventilation opening of the tubular body

23. Graduation of the carrier piece

The frictional vibration damper (1) of the invention consists of a tubular body (2) of plastic and a plunger piston rod (3) moving co-axially in and with the said tubular body (2). A friction element (4) is erted between the inner surface of the tubular body (2) and the outer surface of the piston rod (3) in such a manner that they will move together with the tubular body (2). Ball-and-socket joints (5) are placed onto the respective ends of the piston rod and the tubular body connect the damper to the tub and the cabinet of the washing machine, with axes vertical to the axis of the damper (Figures la and lb).

In addition, the frictional vibration damper (1), of the invention is characterised in that the two rectangular steel sheets are bent into semi-cylinders (9) placed on an H-pro filed (19) carrier piece (10) in such a manner that said steel sheets are eccentric to a degree with respect to the axis of the said carrier piece (10) thanks to the graduation (23) of the carrier piece. A coupling ring (11) comiects the ends of the steel sheets (9) such that the referred steel sheets function together to form the piston rod (3) (Figures 2, 4a, 4b, 5a, 5b, 6a, and 6b).

Carrier piece (10) is made of plastic material on top of which a graduation (23) is formed. This graduation (23) ensures that the steel sheets (9) bent into semi-cylinders can be placed eccentrically with respect to the axis of the carrier piece (10) such that the steel sheets (9) move together with the carrier piece (10) and form a pipe (Figures 3a, 3b, and 3c). The eccentric placement of the steel sheets also prevents the resulting axial moment of the piston rod (3) during its to-and-fro movement within the tubular body (2).

In order to connect the damper (1) with the tub and the cabinet of the washing machine, ball- and-socket joints (5) are placed on the respective ends of the piston rod and the tubular body. The referred joints (5) comprise of a head bearing (6), and a steel bush (7) and a rubber plastic bush (8) which are placed inside this bearing (6). Rubber plastic bush (8) can also be made of steel. These bushes (7, 8) provide the suitable connection to the washing machine.

The piston rod (3) operates with the friction elements (4) while moving telescopically inside the tubular body (2) due to the vibrations caused by the unbalanced movements of the drum of the washing machine.

Four claws (12) are formed on the inner surface of the tubular body (2) which are placed 90- degrees apart. The claws (12) prevent radial deviations that could result from the rotational movement of the piston rod (3) inside the tubular body (2).

An enlargement in the diameter of the body is provided by means of a graduation (13) formed at the lower interior part of the tubular body (2). On this section with a relatively larger diameter, a friction element (4) is fitted. The referred graduation (13) prevents the entry of the said friction element (4) to the narrowing upper portion of the tubulai- body (2).

There is formed a second graduation (14) at the lower interior part of the tubular body (2). The friction element (4) which is placed annually around the piston rod (3) between the first and second graduations (13, 14) is locked to be held together on the tubular body (2) by means of a locking segment (15) provided on this second graduation (14). Hence, all of these elements act as a single piece. All of these elements move together with the tubular body (2) and on the outer surface of the piston rod (3) inserted through the lower portion of the tubular body (2).

The locking segment (15) made of an elastic and durable material is placed at the lower end of the tubular body (2) such that it will apply pressure on the friction element (4). This process is achieved by engaging two claws (16) on the locking segment (15) to the two slots (17) formed on the tubular body (2).

The friction heat created during the operation of the damper is discharged by preferably five cooling fins (18) formed on the exterior surface of the lower end of the tubular body (2) wherein the friction element (4) is placed. As these cooling fins (18) constitute a major cooling area, the air flow which results from the to-and-fro movements of the plastic tubular body (2) due to the unbalanced movements of the drum of the washing machine facilitates the cooling of the damper of the invention. As the drum spin rate increases, the vibration rate i.e. the number of periods the vibration dampers moves to-and-fro, increases. This, in turn, accelerates the air flow around the cooling fin and consequently enhances the cooling process.

Moreover, the friction heat is also discharged through two rectangular ventilation openings (21) formed at the inner part of the support ring (20) which is placed at the lower part of the H-pro filed (19) carrier piece (10). The rectangular ventilation openings camiot be formed unless the carrier piece has the said H-profile, otherwise the excess heat formed due to friction cannot be discharged from the piston rod, and the carrier piece deforms.

Hot air discharged from the above mentioned piston rod (3) into the tubular body (2) is evacuated through the four oval-shaped ventilation openings (22) on the tubular body. These openings (22) not only facilitate the cooling of the piston rod (3) but also prevent the compression of the air in the damper during the vibratory and to-and-fro movements of the piston.

The frictional vibration damper (1) of the invention provides the desired friction force within the allowed tolerance limits, throughout its service life. Moreover, it provides cost effective production by eliminating the processing, procurement, and transport difficulties of steel pipes. Besides, the use of two semi-cylinder shaped steel sheets enables the production of tubes of any thickness which is much more advantageous as compared to the use of steel tubes which are at certain standard thickness levels. The use of thinner steel sheets (9) provide a second source of cost gains. Additionally, the vibration damper(l) of the present invention is cooled better and hence its life time is extended as the thinness of the steel sheet (9) allows rapid discharge of the heat.

Claims

1. A frictional vibration damper for dampening out the vibrations generated by the drum of the washing machines, comprising a plastic tubular body, a plunger piston rod moving co-axially in and with the said tubular body, two graduations, for providing an enlargement of the body diameter on the interior surface of the lower part of the said tubular body; a friction element inserted between the first and second graduations on the inner surface of the tubular body and the outer surface of the piston rod in such a manner that they will move together with the tubular body, and ball-and-socket joints placed on the respective ends of the piston rod and the tubular body to connect the damper to the tub and the cabinet of the washing machine, with axes vertical to the axis of the damper; and characterised in that, said piston rod is composed of two rectangular steel sheets bent into semi-cylinders, a carrier piece whereon said semi-cylinders are mounted, and a coupling ring which comiects the ends of the semi-cylinders such that they function together.

2. A damper according to Claim 1, characterised in that a graduation is formed on top of the carrier piece such that steel semi-cylinders are placed eccentrically with respect to the axis of the carrier piece.

3. A damper according to Claims 1 and 2, characterised in that the carrier piece has an H- profile.

4. A damper according to Claims 1 to 3, characterised in that carrier piece is made of plastic.