Patent Application
20160146351
This invention pertains to mechanical lip seals used in low pressure systems sealing oil and similar fluids from splashing and leaking out of gearboxes.
The prior art utilizes the use of mechanical lip seal assembly consisting of a resilient sealing element made of a low friction plastic such as PTFE, constrained inside a metal canister, this assembly in turn is compressed inside a gearbox housing bore such that the inner lip of resilient sealing element comes in contact with the rotating shaft inside gear box to seal oil and similar fluids from leaking out of gearbox, as the shaft rotates constant friction caused by dynamic surface between sealing lip and rotating shaft results sealing lip wear and seal failure, this invention makes it possible to reduce rate of wear thus improving seal performance and seal life.
This invention contemplates a circular washer sealing element made of low friction plastic such as PTFE with definite inner and outer diameter, looking down flat on one surface of this sealing element there is a circumferential groove located near inner diameter and four angular channels each separated by 90 degrees apart running from circumferential groove inward through inside diameter, two channels located 180 degrees apart from each other angled clockwise from X-axis running left to right and the other two located 180 degrees apart from each other are running counterclockwise right to left from Y-axis, in turn this sealing element is compressed over a flat metallic rosette spring with isolated angular nodes running from inner diameter to the outer such that the surface of resilient sealing element with the circumferential groove and angular channels are located opposite to surface which contacts the metallic rosette spring, combination of resilient sealing element and the rosette spring is compressed together and sandwiched inside a metallic canister and an “L” shaped retainer ring as one assembly, in turn this assembly is compressed inside the gearbox housing bore diameter and as the gearbox shaft is pushed through inside diameter of sealing element from direction of circular groove and four channels expands inner diameter of sealing element creating interference between sealing element and rotating shaft, as the shaft rotates clockwise or counterclockwise with the oil inside gearbox the shaft surface pushes the oil through the angular channels which leads the oil into the circumferential groove located just near sealing lip surface, this constant flow of liquid oil inside circumferential groove creates pressure balancing and less friction resulting longer seal life.
There are 7 pages to the drawing
In the drawing, a lip seal assembly 10 comprising a flat circular washer sealing element 18 made of a resilient low friction plastic such as PTFE, as looking down flat on one surface of this sealing element 18 there is a circumferential groove 26 close to inner diameter and four channels 28 and 30 joining circumferential groove through to inner diameter of sealing element 18, channels 28 and 30 each are 90 degrees apart, channels 28 located on Y-axis of sealing element 18 are 180 degrees apart and channels 30 located on X-axis of sealing element 18 are 180 degrees apart, sealing element 18 thickness (t) is 0.030 to 0.060 inch and circumferential groove 26 with four adjoining channels 28 and 30 are ½ thickness of sealing element 18 (t/2) deep. Channels 28 are angled (∝) degrees clockwise from Y-axis of seal ring 18 where (∝) is between 15 and 30 degrees, channels 30 are angled (∝) degrees counterclockwise from X-axis of seal ring 18 where (∝) is between 15 and 30 degrees. Sealing element 18 and rosette spring 22 are located inside metallic canister 14 and sandwiched between an “L” shaped metallic retaining ring 16 and metallic canister ring 14, sealing element circumferential groove 26 with adjoining four channels 28 and 30 are positioned opposite side of rosette spring 22 and metallic “L” shaped retaining ring 16, maximum diameter “C” of circumferential groove 26 is equal to or less than shaft 12 diameter “D”, this assembly in turn is pressed inside gearbox housing bore 32, shaft 12 is inserted from direction of circumferential groove 26 side and through inside diameter of sealing element 28 expanding inside diameter of sealing element 28 along with rosette spring 22 creating interference with shaft outside diameter surface 12 and sealing element 18 resulting sealing surface 36. When the gearbox is in operation and shaft 12 is rotating in clockwise motion it creates constant oil flow through channels 28 into circumferential groove 26 thus creating pressure balancing and lubricating action at sealing lip surface resulting longer seal life, similarly, with counterclockwise shaft rotation oil is being pushed through channels 30 and creating oil flow into circumferential groove 26 in counterclockwise motion thus resulting balanced pressure and lubricity for sealing lip surface 36 resulting longer seal life. 18 resulting sealing surface 36. When the gearbox is in operation and shaft 12 is rotating in clockwise motion it creates constant oil flow through channels 28 into circumferential groove 26 thus creating pressure balancing and lubricating action at sealing lip surface resulting longer seal life, similarly, with counterclockwise shaft rotation oil is being pushed through channels 30 and creating oil flow into circumferential groove 26 in counterclockwise motion thus resulting balanced pressure and lubricity for sealing lip surface 36 resulting longer seal life.
