Static balance combined high pressure rotary shaft oil seal
The present invention relates to a kind of static balance combined high pressure rotary shaft oil seal, particularly a kind of novel running shaft oil sealing that adopts fabricated structure with the static balance of realizing oil seal body and good eccentric tracing ability.
Rotary shaft oil seal (can certainly be used to seal other the suitable fluid except that mineral oil) is an indispensable important spare part in many machinery of modern industry and the device.Its main field of employment comprises various speed change gears, motor, air compressor, motor, oil pump and oil motor, lathe, metallurgical equipment, mining equiment, chemical industry equipment, food and pharmaceutical equipment, automobile, motorcycle, steamer, aircraft and various building machineries etc.Though oil sealing shared cost in entire equipment is very little, the quality of its performance directly has influence on machine performance and life-span.Protection environment, control are being leaked and polluting the today that requires increasingly stringent, the sealability and the reliability that improve oil sealing have been instant pressing issues.
Existing various rotary shaft oil seal generally all adopts rubber or other engineering plastics as seal (or claiming oil seal body), directly produces to contact with the running shaft surface to seal.On structure, can roughly be divided into two classes, a class is for there being skeleton construction, and another kind of is exoskeletal formula structure.The former skeleton is many to be made with metal, and the elastic sealed body made from soft material is cast and is integral or is pressed into one.Compare with exoskeletal formula, have the oil sealing of skeleton to can be used for higher pressure.Further classification has different structural designs such as single lip and many lips again.Also have the oil sealing of some fabricated structures in addition and adopt high-abrasive material to make the special oil sealing of seal.But which kind of structure no matter all exists following at least two problems at present:
(1) seal this can not balance in radially suffered hydrodynamic pressure, when the working pressure of oil sealing raise, seal lip (being also sometimes referred to as the oil sealing cutting edge) just and produce very high contact stress between the running shaft made heat increase severely, the wearing and tearing aggravation causes oil seal failure and destruction then rapidly;
(2) because seal lip, seal and skeleton etc. are that seal lip is very little with respect to the degrees of freedom of the radial displacement on axle surface in other words for monolithic construction, when the rotation offset of running shaft or vibration are big, the seal lip of ring is difficult to guarantee effectively, hug equably on the axle surface all the time, thereby causes the local leakage of oil sealing and the fatigue stress and the destruction of aggravation seal waist part.Using sliding supported condition transmission shaft and the bigger occasion of load change, this sight resembles especially serious.
In order to address the above problem,, regrettably, do not see the real gratifying oil sealing product of a kind of energy so far yet though relevant producer in various countries and research unit have done a large amount of research and developments and designed some special structures.Actual conditions are that existing oil sealing generally can only use in the very low occasion of pressure (as not being higher than a barometric pressure).Though some has adopted the oil sealing of special material and composite structure can use in the higher occasion of pressure, as five barometric pressure or high pressure more, but because still fail to solve pressure balance and eccentric problem of following performance, under high pressure and the bigger service condition of vibration, the phenomenon of friction and heating is serious, occur easily leaking, operating life is very short.
U.S. Pat discloses a kind of composite seal that uses in high pressure occasion (as oil hydraulic cylinder, hydraulic support etc.) for No. 5269537, comprise a high abrasion elastic sealing ring, it has long body, described body has a pressure end and a non-pressure end, described pressure end has U-shaped cup-like portion and the first dynamic pressure sealing lip that radially inwardly stretches out of this cup-like portion certainly, and described non-pressure end has a closed ring chamber and the second dynamic pressure sealing lip that radially inwardly stretches out of this annular chamber certainly; Be provided with an elastomeric preload ring in the described closed ring chamber, the second dynamic pressure sealing lip is applied constant pretightening force.Realize sealing by entering the radial pressure that sealing medium applies the first dynamic pressure sealing lip in the U-shaped cup annular chamber during work.Because this class application hydraulic medium pressure changes, the radial pressure that causes acting on first sealing lip also changes, when the pressure of hydraulic medium is lower than predetermined minimum pressure, sealing medium can enter the trapped fuel chamber between the first dynamic pressure sealing lip and the second dynamic pressure sealing lip, for preventing that sealing medium from leaking, preload ring acts on the pressure that the constant pretightening force on the second dynamic pressure sealing lip is chosen as greater than hydraulic medium and is lower than predetermined minimum pressure, so that the sealing medium in the trapped fuel chamber flows back to system by the first dynamic pressure sealing lip.Above-mentioned self tightening composite seal, though may have the better seal performance, but as has been noted, and can produce very high contact stress between the reciprocating axle, make heat increase severely, the wearing and tearing aggravation, though as reciprocation sealing the time,, radiating condition lost efficacy rapidly and destruction owing to better being unlikely to cause oil sealing, and can not be as the oil sealing of high-voltage high-speed running shaft.
Shortcoming at above-mentioned prior art existence, purpose of the present invention aims to provide a kind of novel static balance combined rotary shaft oil seal, not only the suffered radial fluid static pressure of seal is whole or in a basic balance, and seal lip and sealing physical efficiency keep good tracing ability and sealing to running shaft surface all the time in a sizable extent of the error.
Static balance combined high pressure rotary shaft oil seal provided by the invention, has a seal, form a seal lip on the inner ring surface of seal, the sealing lip contacts with the outer surface of running shaft, described high pressure rotary shaft oil seal also has a radial location ring, one axial bearing plate, one radial compensation ring and one " O " RunddichtringO, the radial compensation ring is positioned at the space of the inner ring surface qualification of radial location ring, and the bottom supporting of radial compensation ring is on the sealing plane of axial bearing plate, seal is installed in the radial compensation ring, its bottom surface is bearing on the bottom interior surface of radial compensation ring, form an annular space between the inner ring surface of the outer ring surface of seal and radial compensation ring, and seal by described " O " RunddichtringO, form another annular space between the inner ring surface of seal and the outer surface of running shaft, two annular spaces are communicated with fluid-encapsulated, make the inner ring surface of seal and outer ring surface be exposed to fluid-encapsulated among.
Compare with traditional various oil sealings, it is simple to have part processing according to oil sealing proposed by the invention, need not adopt high-temperature molding operation etc. and processing cost is decreased, the suffered static pressure balance of seal or in a basic balance rubs and generates heat for a short time, and the off-centre of axle is followed performance and the anti-vibration performance is good, sealing is strong, the working pressure height, the life-span is long, and installation and maintenance are convenient.In addition, because axle surface only carries out mill with the seal lip of seal, thus can be after the oil sealing use reach projected life, only change seal and continue to use other parts, so that further reduce operating cost.
The oil sealing embodiment who proposes according to the present invention is provided by accompanying drawing 1-4.Wherein:
Fig. 1 is the suffered radial fluid static pressure of a separated type seal equilibrium of forces schematic representation.
Fig. 2 is a kind of sectional view of single seal lip Structures under Hydrostatic Pressure balance combined high pressure oil sealing;
Fig. 3 is the static balance combined high pressure oil seal structure figure that has the auxiliary seal lip;
Fig. 4 represents that a kind of seal lip is the static balance combined high pressure oil sealing of ellipse garden ring surface.
Referring to Fig. 1 and 2, static balance combined high pressure rotary shaft oil seal provided by the invention adopts the fabricated structure design, mainly by radial location ring 1, and axial bearing plate 2, radial compensation ring 3, seal 4 and " O " RunddichtringO 5 parts such as grade are formed.Radial location ring 1 is fitted in (both also can be processed into an integral body) with axial bearing plate 2.Seal lip 41 is opened on the interior toroidal surface of seal 4, pack into the interior toroidal surface of radial compensation ring 3 of the cylindrical anchor ring of seal 4, both can not move to axial along the pressure drop direction but can do radial motion together, and the bottom supporting of radial compensation ring 3 is on the sealing plane of axial bearing plate 2.In order to guarantee that seal can produce leakage from its non-tight face in radially suffered hydrostatic pressure equilibrium of forces or in a basic balance reaching, between the fitting surface of seal and radial compensation ring, installed " O " RunddichtringO 5, as shown in the figure, described seal lip 41 roughly is positioned at the radial extension at " O " RunddichtringO 5 places.Sealing circle 5 also can make seal 4 produce the pretightening force on axle surface and wearing and tearing are compensated.The internal diameter of described radial compensation ring 3 is slightly larger than the internal diameter of described seal lip.Between the periphery of the inner headed face of radial location ring 1 and radial compensation ring 3, enough radial clearances preferably are set, radially move freely together to allow seal 4 and radial compensation ring 3.
For the bottom that makes seal lip 41 and radial compensation ring 3 produces good pre-the contact respectively with between the sealing surface of axle surface S and axial bearing plate 2, can between the interior inclined-plane of the outer inclined-plane of radial compensation ring 3 and radial location ring 1, install " O " type elastic ring 6 (referring to Fig. 2).Certainly also can process a thin-walled elastic ring 31, produce simultaneously axially and radially initial contact force (referring to Fig. 4) at the head of radial compensation ring.
Above-mentioned whole part is assembled into an integral body, and its boundary dimension can be designed to identical or basic identical with existing oil sealing.When assembling is used, only need oil sealing is pressed in the seal mounting hole, block axial bearing plate with a hole with collar and get final product.
Owing to act on interior toroidal surface and the hydrostatic pressure complete equilibrium on the cylindrical anchor ring or (the deciding) in a basic balance of seal 4 on specific design, in theory, no matter how high sealed hydrodynamic pressure have, act on seal lip and do not have obvious change, thereby the working pressure that guarantees oil sealing only is limited by a seal lip and a shearing strength of the boundary lubrication fluid film on surface basically with the lip-deep contact stress of axle.
On the other hand, because seal 4 is radially cooperating for no clearance type with radial compensation ring 3, being radial compensation ring 3 can do enough big radial displacement with respect to axial bearing plate 2 axis of hole (in other words with respect to) with seal 4, so, when axle surface " S " produces eccentric motion or swing, just can drive seal 4 and radial compensation ring 3 by the eccentric contact force of seal lip 41 (or adding auxiliary lip) between the axle surface and do to radially wobble, thereby the additional stress of control action on seal lip 41 is not too large and eliminate other harmful effects with respect to the axial bearing plate 2 static shaft axis of mounting hole and axle (that is with respect to).Furthermore, in the present invention, two motive sealing faces are arranged: the one, a seal lip 41 and a ring-like motive sealing face of high speed circular on surface " S "; The 2nd, the low speed plane sealing face between the bottom of radial compensation ring 3 and axial bearing plate 2 inner surfaces.For the frictional force or the friction torque that keep the latter is a value that size is suitable, can between two planes, offers several ring-like static balance oil groove Cg (only illustrating wherein among the figure) and adopt the material of low coefficient of friction to form frictional plane.For the lower fluid of viscosity, can between described two planes, install the auxiliary seal ring that a soft material is made.
Below, further describe according to the present invention and propose the working principle of novel oil sealing and characteristics etc.
At first, in conjunction with the static pressure of Fig. 1 illustration on seal 4 balance how.For the sake of simplicity, practical problem is simplified to plane problem, as shown in Figure 1.If the pressure of sealed fluid is " p
d", pressure fluid is " L " to the radial force action length of seal, will act on the periphery of seal and the hydrodynamic pressure p on the inner headed face
dBe illustrated respectively in upper half part and lower half portion of " x " axle among the figure.As seen from the figure, as long as the Position Design of seal lip 41 is appropriate, just can make the fluid resultant radial force complete equilibrium that acts on the seal 4.The non-rectilinear part of " x " axle upper pressure distributing line among the figure, the additional contact force that expression produces owing to " O " type circle pressurized.In theory, no matter how high the pressure of sealed fluid have, as long as designs such as the position of seal lip 41 and " O " type circle and the decrement of " O " type circle suitably, all but guarantee effect is in seal static pressure balance radially, and promptly the stress on 41 pairs of axle surfaces of seal lip " S " can not increasing and increase with sealing-fluid pressure.
Fig. 2 is a kind of concrete structure of single lip static balance oil sealing, and oil sealing is by radial location ring 1, axial bearing plate 2, and radial compensation ring 3, seal 4, " O " RunddichtringO 5 and " O " type elastic ring 6 are formed.The effect of " O " type elastic ring is the initial contact that guarantees the sealing surface of 4 pairs of axle surfaces of seal " S " and 3 pairs of axial bearing plates 2 of radial compensation ring.If the eccentric swing amount on axle surface " S " is bigger, then seal 4 and radial compensation ring 3 will be done corresponding swing with respect to the sealing surface of axial bearing plate 2, and the situation that seal lip 41 breaks away from axle surface " S " can not occur simultaneously along with the swing of axle.Be the friction between the sealing surface of the bottom surface of reducing radial compensation ring 3 and axial bearing plate 2, can offer several annular static balance oil groove Cg in the bottom surface of radial compensation ring 3, and sealed fluid led in a certain circular groove of people, leak but do not make fluid pass through the sealing face simultaneously again.
Fig. 3 is illustrated in the static balance formula oil seal structure of having offered several auxiliary lips on the interior toroidal surface of radial compensation ring 3.Oil sealing is still by radial location ring 1, axial bearing plate 2, and radial compensation ring 3, seal 4, " O " RunddichtringO 5 and " O " type elastic ring 6 are formed.Different with previous embodiment is: in the present embodiment, the interior toroidal surface diameter of radial compensation ring 3 and the diameter of seal lip 41 are almost equal, and have offered several circular grooves or spiral chute thereon, constitute several auxiliary lips.This structure especially is adapted to the bigger occasion of the surperficial beat of axle.
Fig. 4 illustrates the static balance combined high pressure oil sealing that a kind of seal lip is ellipse garden ring surface, and it is by radial location ring 1, axial bearing plate 2, and radial compensation ring 3, seal 4, " O " RunddichtringO 5 is formed.In order to reduce the temperature rise and the wearing and tearing of oil sealing seal lip 41 and surperficial contacting point of axle when the high speed operation, make seal 4 keep under the prerequisite of static balances the toroidal surface of seal lip being made an ellipse ring surface with respect to the axle surface tilt.In other words, the shaft axis of this ellipse ring surface forms an included angle A with the center line of axle.Like this, when axle rotates, seal lip always periodically changes with the contact segment on axle surface, all the time there is sealed fluid to enter in the endless belt contact area on seal lip and axle surface, the ceaselessly lubricated and cooling to replacing property of contact surface even under the condition that does not have the external forced cooling, still can improve the heat radiation situation of sealing surface greatly, reduce temperature rise and wearing and tearing, prolong the working life on oil sealing and axle surface.This oil sealing especially is adapted to high rotating speed occasion.
It is pointed out that the foregoing description, only for explanation with understand the present invention; The basic principle that proposes according to the present invention also can produce other distortion or derivatives such as many lips formula axle envelope etc.The principle of seal and seal ring main body being separated, made its suffered fluid pressure balance that the present invention proposes is equally applicable to make static balance formula sliding ring etc.Protection scope of the present invention should be limited by each claim.