WO2011056160A1

WO2011056160A1 - Radial sealing element

Info

Publication number: WO2011056160A1
Application number: PCT/TR2010/000215
Authority: WO
Inventors: Burak Karababa
Original assignee: Bsh Ev Aletleri San. Ve Tic. A.S.
Priority date: 2009-11-06
Filing date: 2010-10-28
Publication date: 2011-05-12

Abstract

The present invention proposes a sealing element wherein first flexible element (13) and said third flexible element (19) jointly pressing upon said annular body (18) provides a consistent load balance maintaining the seal without causing wear and the second annular body features a special upper silhouette (21) with a planar base (22), therefore receiving a single- dimensional contact from said first flexible element above.

Description

RADIAL SEALING ELEMENT

Technical Field of the Invention

The present invention relates to an annular sealing element intended to be used in fluid pumps in automotive type engines or in washing machines and the like.

Background of the Invention

Various designs have been utilized to ensure proper sealing in fluid pumps, generally featuring a flexible annular body pressing on the shaft to form a sealed division within the machine. For ensuring proper sealing, a designer needs to consider both dynamic and static sealing requirements. Dynamic sealing is achieved by ensuring a smooth, specially treated shaft surface on which the flexible annular sealing element presses upon. Otherwise, end face load applied to the sealing brings about rapid wearing and excess heat consumption such that part of the system energy is dissipated between the shaft and the flexible sealing element. Further, undue temperature rise and rapid wear may also be induced in case the parts are not initially fit tightly enough, leading to an insufficient load and to leakage of the fluid, such fluid normally being water or a water/glycol mix. Therefore the sealing element has necessarily to bear snugly against the shaft. Nevertheless, its life is limited because of the attrition by the action of the shaft. Further, to ensure static sealing, the sealing element must be tightly fit onto the shaft such that strict measurement tolerances are observed to avoid improper alignment of the sealing element. Otherwise, eccentricity of the sealing element will cause lack of required pressure to obtain dynamic leakproofness. The present invention provides a special sealing element design overcoming the above shortcomings such that friction and energy dissipation are reduced, build-up of deposits on the shaft is eliminated.

The sealing arrangement according to the present invention features a three-part sealing element compensating both axial geometrical clearance defects and radius imperfections of the shaft. A first flexible element capable of displacing both along axial and radial directions when there is dynamic runout occurring, maintains contact with a second annular body directly pressing on the shaft. Dynamic compensation characteristic imparted to the first flexible element provides a consistent load balance maintaining the seal without causing wear. Said second annular body operating in coordination with said first flexible body as a geometrical couple ensures that no excess heat is dissipated and no corrosion occurs during operation.

Said second annular body features a special upper silhouette with a planar base, therefore receiving a single-dimensional contact from said first flexible element above. A one-dimensional contact with said first flexible element is advantageous in that said first flexible element is allowed slightly more displacement in axial and radial directions compared to a surface contact, whereby load fluctuations are better absorbed.

According to the present invention, a third sealing body made out of viscoelastic material compensates clearance defects and provides efficient sealing in coordination with said first flexible element and said second annular body. Said third viscoelastic body further comprises a radially extending flange along an inner boundary of said viscoelastic annular body. The flange, normally lying at an oblique angle with respect to the radial axis, changes its direction and extends perpendicular to the shaft axis at speeds starting from above 100 rpm. This change from a stowed position to a deployed position under centrifugal force increase axial forces and diminishes radial attrition. It further ensures that deposits previously built up on the flange are scraped off as well as liquid particles on the flange are scattered.

Said second annular body receives a surface contact from said third flexible sealing element ensuring that said annular body laterally bears against the shaft in a secure manner.

Objects of the Invention

One of the objects of the present invention is to provide a sealing element intended to be used in fluid pumps in which friction and energy dissipation are reduced, build- up of deposits is eliminated.

Another object of the present invention is to provide a sealing element intended to be used in fluid pumps in which both axial geometrical clearance defects and radius imperfections of the shaft are compensated.

Another object of the present invention is to provide a sealing element intended to be used in fluid pumps in which a consistent load balance maintains the seal without causing wear.

Summary of the Invention

The present invention proposes a sealing system intended to be used in fluid pumps comprising a first flexible element pleated in an accordion-like manner and displaceable in axial and radial directions, a second annular body directly pressing on the shaft and a third flexible element having an annular flange outwardly deployable above 100 rpm under centrifugal force. Said first flexible element and said third flexible element jointly pressing upon said annular body provides a consistent load balance maintaining the seal without causing wear. This directional change of the flange from a stowed position to a deployed position while increasing axial forces and diminishing radial attrition, it further ensures that deposits built up on the flange are scraped off and pressure drop on the sealing arrangement is reduced. Said first flexible element having accordion-like convolutions provide increased lateral stability and/or increased cushioning capacity.

Brief Description of the Figures Accompanying drawings are given solely for the purpose of exemplifying a sealing system in which:

Fig. 1 demonstrates a perspective view of the sealing element according to the present invention.

Fig. 2 demonstrates a perspective view of the sealing element according to the present invention in a pre-mounted condition.

Fig. 3 demonstrates a cross-sectional view of the sealing element according to the present invention. Detailed Description of the Invention

Referring now to the figures outlined above, the present invention proposes a sealing system generally designated 11. The sealing system (1 1) basically comprises a set of components operable in coordination to effect sealing of the drive shaft (12).

The sealing system (11 ) primarily comprises a first flexible element (13) extending in an annular manner and having accordion-like folds to absorb imbalance of both axial and radial force components due to load fluctuations. Said first flexible element (13) is essentially comprised of a plurality of folding turns (14) between any consecutive two of which the length of the non-linear segments diminishes in the direction of the central longitudinal axis of the shaft (12), finally leading to a linear end segment normal to the shaft (12) surface. The end part is designated 15. Said flexible element (13) is designed to be firmly disposed within the pump assembly with its outer rear wall (16) is annularly secured to a retaining surface (17).

The end part (15) of said first flexible element (13) bears against an annular ring-like body (18) in direct contact with said shaft (12). Said first flexible element (13) displaceable both in axial and radial directions and said annular ring-like body (18) as a geometrical couple, ensure that no excess heat is dissipated and no corrosion occurs on the shaft (12) surface as consistent load balance maintains the seal without causing wear Axial geometrical clearance defects and radius imperfections of said shaft (12) are therefore compensated. The first flexible element (13) according to the present invention presses upon said annular ring-like body (18) via its end part (15) such that said annular body (18) is squeezed between said first flexible element (13) and a third flexible sealing element (19) in an axial direction. In other words, said first flexible element (13) exerts an axial force in the direction of the longitudinal shaft (12) axis on said annular body (18).

Said third flexible sealing element (19) comprises a radially extending flange (20) along its inner boundary. The flange (20), normally lying at an oblique angle with respect to the radial axis, changes its direction and extends perpendicular to the shaft (12) axis at speeds starting from above 100 rpm. This change from a stowed position to a deployed position under centrifugal force increase axial forces and diminishes radial attrition. It further ensures that deposits previously built up on the flange are scraped off as well as liquid particles on the flange are scattered.

The oblique flange (20) provides a double-effect use according to the present invention. Primarily, it imparts rotary movement to the surrounding fluid, thereby lowering pressure thereof and as well as the pressure applied on the overall sealing system and secondly it further lowers pressure drop on the direct surrounding of the sealing system by producing a vacuum-like annular region swept by its rotation around a root point of said flange (20) under centrifugal force. Said region is illustrated in Fig 1 in which the flange (20) repositions itself on the B-B' direction, thereby sweeping a space delimited between its original and final directions.

Said third flexible sealing element (19) further serving to the purpose of masking manufacturing defects on the shaft (12) surface as axial forces increase radial attrition diminishes due to relocation of the annular flange (20). Fig. 1 and Fig 2 demonstrate the sealing system (11) according to the present invention in perspective views. The relative disposition of said first flexible element (13), said annular body (18) and said third flexible sealing element (19) is more clearly seen in those figures. With reference to Fig. 2, said first flexible element (13) and said third flexible sealing element (19) squeezes said annular body (18) from above and below in the immediate vicinity of the shaft (12) surface. Said annular body (18) having a dome-like cross-section upper half (21) with a planar base (22) receives a single-dimensional contact from said first flexible element (13) above and a surface contact from said third flexible sealing element (19) below. A one- dimensional contact with said first flexible element (13) is advantageous in that said first flexible element (13) is allowed slightly more displacement in axial and radial directions compared to a surface contact whereby load fluctuations are better absorbed. On the other hand, a surface (23) contact neighboring a lateral surface (24) between said third flexible sealing element (19) and said annular body (18) ensures that said annular body (18) laterally bears against said shaft.

Said flange (20) of said third flexible sealing element (19) according to the present invention is designed such that the length of the axial portion (24) of said third flexible sealing element (19) equals to the axial component of said flange (20) extension vector. In other words, said flange (20) extension greater than said axial portion (24) of said third flexible sealing element (19) in length helps increasing axial forces and diminishing radial attrition under centrifugal force.

Claims

Claims:

1. An annular sealing system for rotating liquid pumps comprising a first flexible element (13) bearing against a second annular body (18) being in contact with a shaft (12) portion and a third flexible sealing element (19) bearing against said shaft (12) and said second annular body (18) wherein second annular body (18) has a single-dimensional uppermost part (21) and a planar base part (22) receiving a single-dimensional contact from said first flexible element (13) above and a surface contact from said third flexible sealing element (19) below.

2. An annular sealing system as in Claim 1 wherein said first flexible sealing element (19) is securely disposed to absorb imbalance of axial and radial force components by means of a plurality of accordion-like folds.

3. An annular sealing system as in Claim 1 or 2 wherein said first flexible elements' (13) presses upon said annular ring-like body (18) via an end part (15) such that said annular body (18) is squeezed between said first flexible element (13) and said third flexible sealing element (19) in an axial direction.

4. An annular sealing system as in Claim 1 or 4 wherein said first flexible element (13) is designed to be firmly disposed within the pump assembly with its outer rear wall (16) being annularly secured to a retaining surface (17).

5. An annular sealing system as in Claim 1 or 4 wherein said first flexible element (13) exerts an axial force in the direction of the longitudinal shaft (12) axis on said annular body (18) from above in the immediate vicinity of the shaft (12) surface.

6. An annular sealing system as in any previous claims wherein said has a radially extending flange (20) along an inner boundary, said flange (20) lying at an oblique angle with respect to the radial axis.

7. An annular sealing system as in Claim 6 wherein said third flexible sealing element (19) is designed such that the length of the axial portion (24) of said third flexible sealing element (19) equals to the axial component of said flange (20) extension vector.

8. An annular sealing system as in Claims 6 or 7 wherein said flange (20) extension of said third flexible sealing element (19) is greater than said axial portion (24) of said third flexible sealing element (19) in length.

9. An annular sealing system as in Claim 7 or 8 wherein said flange (20) extension of said third flexible sealing element (19) is greater than said axial portion (24) of said third flexible sealing element (19) in length.