Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16J—PISTONS; CYLINDERS; SEALINGS
  • F16J15/00—Sealings
  • F16J15/16—Sealings between relatively-moving surfaces
  • F16J15/26—Sealings between relatively-moving surfaces with stuffing-boxes for rigid sealing rings

Definitions

• the present invention relates to a piston rod sealing ring made of plastic with an overlapping sealing joint.
• Piston rod sealing rings of the type mentioned are used in gland seals for piston rods of internal combustion engines. Such gland seals are known in particular for marine diesel engines and are described, for example, in documents DE-B-21 '14' 152 or EP-A-0 '138' 443. Stuffing boxes for piston rods usually form the separation between the crankcase and the purge air space. A number of oil scraper rings are first arranged in the stuffing box for a piston rod on the crankcase side, followed by one or more sealing rings on the cylinder side. The sealing rings, which are to achieve a gas-tight contact with the piston rod, must therefore always be under pressure on the piston rod.
• Figure 1 is a gland seal in a simplified and type-independent form in a perspective, partially sectioned representation.
• FIG. 2 shows a piston rod sealing ring according to the invention in the assembled state in axial supervision
• Figure 3 shows the same piston rod sealing ring in a radial view of the overlapping joint
• Figure 4 shows the piston rod sealing ring made of plastic in turn in the top view in the axial direction
• FIG. 5 this piston rod sealing ring in a radial view again with a view of the overlap area.
• Figure 6 shows the arched bridging element by itself in axial supervision and
• FIG. 8 is a conventional piston rod sealing ring which forms the prior art and is shown in an axial top view
• FIG. 9 shows a section along the line AA in FIG. 8 in the region of the overlapping joint.
• FIG. 1 the structure of a stuffing box seal, as it is used in particular for marine diesel engines, is explained with reference to FIG.
• This stuffing box seals seal Crankcase opposite the purge air space.
• the purge air space lies in the direction of arrow Z and the crankcase in the direction of arrow K.
• the stuffing box has a stuffing box housing 1 in which numerous receiving grooves 2 are attached to the inner wall thereof.
• several oil scraper rings 3 are inserted on the lower half lying on the crankcase side, by means of which the oil adhering to the crank rod is scraped off and returned to the crankcase space.
• Appropriate leakage outlets 4 are provided in the housing of the stuffing box for this purpose.
• the area in which the oil scraper rings 3 are stored in the stuffing box housing is referred to as the scraper zone, while the sealing zone of the stuffing box follows in the direction of the purging air space.
• circumferential annular receiving grooves 2 are also formed, and in these are the sealing rings 5.
• the sealing rings 5 are shown as conventional sealing rings, while the oil scraper rings 3 are special scraper rings developed by the applicant, which are made of the WO 03/044400 are known.
• the spiral springs causing the contact pressure on the oil control rings 3 or on the sealing rings 5 are not shown. Of course, these must be available. The omission is only made so as not to unduly burden the drawing.
• FIGS. 8 and 9 represent a piston rod sealing ring according to the prior art, as is already offered by the applicant on the market today.
• the sealing ring 5 is made in one piece here and has an overlapping, gas-tight joint 6. This overlapping, gas-tight shock is shown in section in FIG. In the overlap region, a first ring end 7 overlaps the other, second ring end 8. Here, the ring end 7 lies with a sliding surface 9 on the ring end 8 in a sealing manner.
• the second overlapping surface 9 is a sealing surface 9a which is hardly loaded in terms of force and on which practically no abrasion can be determined.
• the abrasion on these surfaces is shown schematically in black and marked with the letter W.
• the abrasion W is favored, on the one hand, since two identical plastic parts slide on one another, and additionally, because here the closed spiral springs run through the circumferential in the arcuate grooves R, which generate a radial pressure towards the piston rod axis.
• the plastic piston rod sealing ring according to the invention in the assembled state.
• the actual plastic sealing ring is designated 10.
• This plastic part is in one piece and has an arcuate overlap area 12 which in the Size varies according to the adaptation to the diameter of the piston rod, according to its change due to wear.
• the plastic sealing ring 10 On the outer circumferential surface, the plastic sealing ring 10 has one or more circumferential grooves 13, which serve to guide the circumferential spiral springs 14 located therein.
• the coil springs 14 can be put together via a lock consisting of a molded ring eyelet and a molded hook eyelet. Depending on the desired pressure force, up to three such spiral springs can be provided.
• In the radial direction in the region of the joint 6 there is an arcuate bridging element 15 made of metal.
• This bridging element 15 also has grooves 16 which are aligned with the grooves 13 on the plastic sealing ring 10 in the assembled state.
• the plastic sealing ring 10 has an inwardly directed peripheral recess 17 which is wider than the overlap area 12.
• the arched bridging element 15 made of metal is definitely smaller in its longitudinal extent than the inwardly directed peripheral recess 17 when the plastic sealing ring is at its minimum Takes up diameter.
• the inward peripheral recess 17 has a bottom, which serves as a sliding surface 18 for the arched bridging element 15.
• the arcuate bridging element 15 and the inward peripheral recess 17 must be adapted to one another.
• the radius of the bridging element 15 can be slightly larger than the radius the sliding surface 18 of the inward peripheral recess 17. These two radii then adapt to one another after a short time due to wear. In this regard, reference is again made to the later figures.
• the plastic sealing ring 10 is shown on its own.
• the plastic sealing ring 10 has an inner sealing surface 11, which is in contact with the piston rod in the installed state.
• the sealing surface on the piston rod 11 can be designed as a full-surface circular cylindrical surface, or divided into two or more parallel cylindrical sealing lips 19 which together form the sealing surface 11 Sealing lips 19 are only partially visible in the view according to FIG. 5, where the two sealing ring tabs 20 and 21 do not overlap in the axial direction.
• the overlapping area 12 of the two sealing ring tabs 20 and 21 together form a gas sealing surface 22.
• the peripheral recess 17 can be seen over the entire length of the two sealing ring tabs 20 and 21 and extending further in the circumferential direction on both sides.
• the gas sealing surface 22 is not per se visible in FIG. 5, but it has been indicated here in the form of a dotted surface 22.
• This dotted surface 22 has two sections which are dotted to different extents.
• the tightly dotted area is the area in which the two sealing ring tabs 20 and 21 in the unloaded state, as here shown overlap, while the less densely dotted area in the assembled and spring-loaded state are also sealingly one above the other.
• An excessive sliding surface 23 is present here centrally in the peripheral recess 17. This excessive sliding surface 23 extends in the peripheral extent over the two sealing ring flaps 20 and 21 and beyond them.
• the circumferential grooves 13 already mentioned can be seen, which, with the exception of the region of the peripheral recess 17, can be seen on the outer circumferential surface of the plastic sealing ring 10 extend over the entire circumference.
• FIGS. 6 and 7 show the bridging element 15 on its own.
• the bridging element 15 is made of metal. This can be made from a conventional machine steel.
• the bridging element 15 has lateral boundary surfaces 25 which end in peripheral chamfers 26.
• 15 grooves 16 are formed in the bridging element on the outer surface.
• Circumferential ribs 27 remain between each two adjacent grooves 16.
• the two end faces 28 of the bridging element 15 run in an exactly radial direction.
• the material hardness of the bridging element 15 is substantially higher than the hardness of the plastic sealing ring 10. Consequently, wear will only occur on the sliding surface 18 or on the excessive sliding surface 23 of the plastic sealing ring 10 during use.
• the excessive sliding surface 23 brings about an additional stiffening of the plastic sealing ring 10 in this area, at least in the initial phase.
• the excessive sliding surface 23 may gradually rub off. If the elevation is completely rubbed off, this area will in principle be aligned with the non-raised lateral sliding surface areas 18 'and 18''. Even then, the plastic sealing ring 10 does not need to be replaced.
• the sealing ring flaps 20 have now become thinner and correspondingly more flexible due to the corresponding wear in the radial direction. At the same time, however, a certain amount of wear and tear may have occurred on the piston rod, especially with uncured piston rods. This means that the radius of the plastic sealing ring 10 has decreased somewhat.
• the bridging element 15 is now practically only in the central region, since the diameter of the inner surface of the arcuate bridging element 15 is now larger than the diameter or the radius of the plastic sealing ring 10. Overall, this results in a significantly increased service life of the plastic sealing rings 10 and, at the same time, thanks to the use of the plastic sealing rings, less wear on the piston rod. Both together naturally also mean that the oil consumption of a marine diesel engine which is equipped with bushings with the plastic sealing rings according to the invention is significantly lower.
• an intermediate ring is preferably attached, which acts both as an oil scraper ring and as a sealing ring.
• This ring is shown throughout in FIG. 1.
• the ring differs essentially in that it has cams extending on one side in the axial direction over the side surfaces of the ring, between which gaps remain free, through which preferably contaminated oil can flow into the neutral space. This prevents the dirty oil from getting into the crankcase.
• These rings which despite the double function are referred to here as sealing rings, can also have the inventive design of the gas-tight joint 6 with a bridging element 15. List of reference numbers

Landscapes

• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Sealing Devices (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=34961747

Family Applications (1)

Country Status (4)

Family Cites Families (9)

• 2005
  • 2005-03-18 JP JP2007506631A patent/JP4757866B2/ja not_active Expired - Fee Related
  • 2005-03-18 WO PCT/CH2005/000163 patent/WO2005098283A1/de not_active Application Discontinuation
  • 2005-03-18 EP EP05714705A patent/EP1733159A1/de not_active Withdrawn
  • 2005-03-25 TW TW94109324A patent/TWI331648B/zh not_active IP Right Cessation

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events