JP4757866B2 - Piston rod sealing ring - Google Patents

Description

  The present invention is a synthetic resin piston rod sealing ring having an overlapping sealing joint.

  A piston rod sealing ring of the type described above is used for a gland seal of a piston rod of a combustion engine. Such gland seals are known, inter alia, in ship diesel motors and are described, for example, in documents DE-B-21'14'152 or EP-A-0'138'443. The piston rod packing press usually forms a separation between the crank housing and the scavenging chamber. On the crank housing side, a number of oil scraper rings are first placed in the packing presser for the piston rod, followed by several sealing rings on the cylinder side above it. In general, the sealing ring to achieve the airtight contact of the piston rod must always withstand the pressure of the piston rod.

  According to experiments, maximum wear inevitably occurs in the region of the top dead center and bottom dead center of the piston rod. The wear of piston rods in the range of 1-2 mm in diameter is the normal scale that occurs here. From this point, the top dead center and bottom dead center regions are lightly touched by the sealing ring twice per stroke of the piston. Therefore, the sealing ring in the overlapping area of the sealing joint must make a relative movement of about 3-6 mm. At the same time, the lower tongue portion and the upper tongue portion of the sealing joint slide with each other. On the one hand, due to the direct frictional effect of the two tongues made of the same metal, on the other hand, the peeling of the metal dragged inside the oil acting as a lubricant itself, the sealing joints lying simultaneously on each other Both sides of the two tongues are subject to wear. Highly contaminated oil increases the frictional wear of the two tongues of the sealing joint. Due to the use of a metal piston rod sealing ring, the problem of sealing ring wear in such joint areas is relatively minor and is limited to sealing rings made of soft metals such as bronze, for example. . More important is the discovery that the metal piston rod sealing ring leads to very high frictional wear on the piston rod itself, which means that the overall sealing performance is poor, which is caused by this. Leads to an increase in crank oil consumption with every possible malfunction. As a result, more and more piston rod packing retainers have oil scraper rings and sealing rings made of synthetic resin. This has greatly reduced piston rod wear, and oil consumption has also been minimized, but the sealing ring will need to be replaced more and more as it deteriorates faster than expected. Has been shown. Replacing these synthetic resin rings has been found to cause unexpected leakage in the sealing ring near the sealing joint. The sealing ring discussed here is initially placed on the packing presser as disclosed in WO 91/14890.

  As a result, an object of the present invention is to improve a synthetic resin piston rod sealing ring having an overlapping sealing joint so as to increase life and maintain a seal even in the presence of partial wear. A synthetic resin piston rod sealing ring having the features of claim 1 achieves this object. Further advantageous embodiments are inferred from the dependent claims, the importance and method of operation of which are explained in the following description with reference to the accompanying drawings.

  One preferred embodiment according to the content of the invention is illustrated in the drawing and will be explained in more detail in the following description.

  For a better understanding of the present invention, referring to FIG. 1, the structure of a packing retainer seal is described which is particularly suitable for a ship diesel power unit. This type of packing retainer seal seals the crank chamber with respect to the scavenging chamber. In FIG. 1, the scavenging chamber is arranged in the arrow Z direction, and the crank housing is arranged in the arrow K direction. The packing presser has a packing presser seal 1 in which various receiving grooves 2 are incorporated in the inner wall. Some oil scraper rings 3 are means for rubbing oil that has soaked into the crank rod and returning the oil into the crank housing chamber, and are disposed in the annular groove 2 in the lower half on the crank housing side. For this reason, an appropriate leaked oil outflow portion 4 is provided in the housing of the packing presser. The oil scraper ring 3 area provided in the packing retainer housing is referred to as the rubbing area, while the sealing area of the packing retainer continues above this in the direction of the scavenging chamber. Similarly, a peripheral annular receiving groove 2 is formed inwardly in this sealing area, and a sealing ring 5 is arranged in these. In this depiction, the sealing ring 5 is shown as a conventional sealing ring, whereas the oil scraper ring 3 is the case of a special scraper ring known from WO 03/044400, which has been developed by the applicant. . In the form of the packing presser seal shown here, the spiral spring that generates the supporting pressure on the oil scraper ring 3 or the sealing ring 5 is not shown. However, these are of course present. This omission is only made so that the drawing is not too complicated.

  Again to address the problems of conventional piston rod sealing rings, reference is made in this regard to FIGS. 8 and 9, which show the most advanced piston rod sealing rings already on the market on the part of the applicant. Here, the sealing ring 5 is integrally formed and has an overlapping airtight joint 6. This overlapping hermetic joint is shown in cross section in FIG. At the same time, the first ring end 7 is engaged with the other second ring end 8 in the overlapping region. At the same time, the ring end 7 supports one sliding surface 9 on the ring end 8 in a sealed state. The second sliding surface 9 is a sealing surface 9a that is confirmed to be substantially free from friction and wear with little force applied. The frictional wear on these surfaces is shown schematically in black and is designated W. Here, two synthetic resin parts slide on each other, and the surrounding spiral springs move closer in the arc-shaped groove R, and the springs generate radial pressure in the axial direction of the piston rod. On the other hand, the frictional wear W is promoted.

  In FIG. 2, the synthetic resin piston rod sealing ring according to the invention in the assembled state will be recognized. The actual synthetic resin sealing ring is indicated by reference numeral 10. This synthetic resin portion is formed of a single member and has an arc-shaped overlapping region 12, which is adapted to the piston rod diameter and varies in size depending on changes due to wear. This synthetic resin sealing ring has an outer peripheral groove 13 that plays a role of guiding an outer peripheral spiral spring 14 disposed therein on the outer peripheral surface. The spiral spring 14 may be connected via a locking portion including a ring-shaped small hole formed integrally and a hook-shaped small hole formed integrally. Depending on a predetermined pressing force, a maximum of three such peripheral spiral springs may be provided. In the region of the joint 6, a metal arc-shaped connecting element 15 is provided in the radial direction. The connecting element 15 similarly has a groove 16, and the groove 16 is provided on the same plane as the groove 13 of the synthetic resin sealing ring 10 in the assembled state. The synthetic resin sealing ring 10 has an outer peripheral recess 17 that is recessed inwardly wider than the overlapping region. However, when assuming the minimum diameter of the synthetic resin sealing ring, the metal arc-shaped connecting element 15 is smaller in any case than the outer peripheral recess 17 whose longitudinal extension faces inward. This inwardly facing outer peripheral recess 17 has a bottom that serves as a sliding surface 18 for the arc-shaped connecting element 15. The arc-shaped connecting element 15 and the inwardly facing outer peripheral recess 17 must be adapted to each other. However, in principle, the radius of the connecting element 15 may be slightly larger than the radius of the sliding surface 18 of the outer peripheral recess 17 facing inward. These two radii fit together due to their slight time after friction. In this regard, reference will be made again to the subsequent drawings.

4 and 5, the synthetic resin sealing ring 10 is shown alone. The synthetic resin sealing ring 10 has an inner sealing surface 11 that supports the piston rod in the inserted state. The inner sealing surface 11 on the piston rod may be entirely configured as an annular cylindrical surface or divided into two or more parallel-acting annular cylindrical sealing edges 19 that together form the inner sealing surface 11. May be. The sealing edge 19 is only partially revealed in FIG. 5, where the two sealing ring tongues 20 and 21 do not overlap in the axial direction. The two sealing ring tongues 20 and 21 together form an airtight surface 22. It will be appreciated that the peripheral recess 17 extends the entire length beyond the two sealing ring tongues 20 and 21 and further extends in the circumferential direction. In FIG. 5, the airtight surface 22 is not clear, but is shown here by the method of displaying the surface 22 in the stipple method. The stipple 22 has two parts drawn with a wide range and a narrow range of points. Of these, the dense stippled region is the region where the two sealing ring tongues 20 and 21 overlap in an unloaded state, as shown here, while the relatively dense stippled region is exposed to spring pressure in the assembled state. They are exposed and overlap each other in a sealed state.

  Here, the raised sliding surface 23 exists in the center of the outer peripheral recess 17. This raised sliding surface 23 extends beyond the two sealing ring tongues 20 and 21 in the outer peripheral extension. In this case, the non-raised side sliding surface regions 18 ′ and 18 ″ are present in the lateral direction of the raised sliding surface 23. It will be understood that the above-described outer peripheral grooves 13 are on the outer peripheral surface of the synthetic resin sealing ring 10, and these grooves extend over the entire outer periphery with the exception of the outer peripheral recess 17 region.

  A tether 15 is shown in FIGS. The connecting element 15 is manufactured from metal. This may be made of conventional mechanical steel. The connecting element 15 has a side limiting surface 25 having an outer peripheral chamfer 26 formed at the end. As described above, the groove 16 is formed inside the outer surface of the connecting element 15. The outer peripheral rib 27 remains between the two adjacent grooves 16 in any case. The two end faces 28 of the connecting element 15 are precisely oriented in the radial direction.

  The material hardness of the connecting element 15 is significantly higher than the hardness of the synthetic resin sealing ring 10. As a result, wear in use only occurs on the sliding surface 18 or the raised sliding surface 23 of the synthetic resin sealing ring 10. At least in the initial stage, the raised sliding surface 23 causes further hardening of the synthetic resin sealing ring 10 in this region. During the service life of the synthetic resin sealing ring 10, wear of the raised sliding surface 23 will gradually occur. If this ridge is worn out completely, in principle this region will be flush with the non-raised side sliding surface regions 18 'and 18 ". However, even in this case, the synthetic resin sealing ring 10 does not need to be replaced. In particular, the sealing ring tongue 20 is thin at this time and is correspondingly relatively flexible due to the corresponding wear. At the same time, however, some piston rod wear may occur, especially with uncured piston rods. This means that the radius of the synthetic resin sealing ring 10 is somewhat reduced. However, since it will be confirmed that there is substantially no wear on the connecting element 15, the inner diameter of the arc-shaped connecting element 15 is larger than the diameter of the synthetic resin sealing ring 10. Are also arranged only in the intermediate region. This greatly extends the life of the synthetic resin sealing ring 10 as a whole, and at the same time, less piston rod wear is achieved thanks to the use of the synthetic resin sealing ring. Of course, both of these lead to the fact that the oil consumption of a ship's diesel engine with a bushing having a synthetic resin sealing ring according to the invention is significantly reduced.

  Preferably, a ring provided in the middle is attached between the oil scraper ring 3 and the sealing ring 5, and the ring serves as an oil scraper ring together with the sealing ring. This ring is depicted in FIG. 1 in a continuous manner. The ring is essentially different in that it has a cam that extends on one side of the ring on the side of the ring, leaving an intermediate space between them, which preferably causes contaminated oil to remain. Can flow into the neutral space. This prevents contaminated oil from inside the crank housing. These rings may also have the configuration of the gas joint 6 with the connecting element 15 according to the invention, despite having the dual function depicted here as a sealing ring.

The perspective view containing the partial cross section which shows the simplified independent type packing presser seal. FIG. 3 is an axial view of a piston rod sealing ring according to the present invention in an assembled state. The figure which shows the same piston rod sealing ring seen from the radial direction of the overlap area | region . The figure which looked at the same piston rod sealing ring of synthetic resin from the axial direction. The figure of the piston rod sealing ring seen from the radial direction on the overlap region. The figure which looked at the connecting element which consists of an arc shape from the axial direction. The figure which looked at the connecting element which consists of an arc shape from the radial direction. The figure which looked at the conventional cutting-edge piston rod sealing ring from the axial direction. A-A line sectional view of FIG. 8 in the heavy Do Ri realm.

Explanation of symbols

K crank housing R groove W wear Z scavenging chamber 1 packing press housing 2 receiving groove 3 oil scraper ring 4 leaked oil outflow portion 5 sealing ring 6 overlap joint 7 first ring end 8 second ring end 9 sliding surface 9a sealing surface 10 Synthetic resin sealing ring 11 Sealing surface 12 Overlapping region 13 Outer peripheral groove 14 Spiral spring 15 Linking element 16 Groove in connecting element 17 Outer peripheral recess 18 Sliding surface 18 'Non-raised side sliding surface area 18''Non-raised side sliding Moving surface area 19 Sealing edge 20 Sealing ring tongue 21 Sealing ring tongue 22 Airtight surface 23 Raised sliding surface 25 Side limited surface 26 Chamfer 27 Peripheral rib

Claims (2)

In the piston rod sealing ring assembly,
An inner sealing surface (11), an outer peripheral recess (17) provided on the outer side and recessed radially inward, and an overlapping region (12) formed radially inward from the outer peripheral recess (17) A synthetic resin sealing ring (10) having
The sealing ring (10) is disposed in the outer peripheral recess (17), and the whole comprises the sealing ring (10) and a metal connecting element (15) having an arc shape that completely overlaps in the radial direction,
The outer circumferential recess (17) serves as a sliding surface (18) between the sealing ring (10) and the connecting element (15),
The outer peripheral recesses (17) are widely than the overlap region (12),
The sliding surface (18) is formed concentrically with the inner sealing surface (11) of the sealing ring (10),
The central region of the outer peripheral recess (17) wider than the overlapping region (12) is thicker than the side recess regions located on both sides of the center region in the radial direction, and the inner sealing surface (11) is similar to the side recess region. A piston rod sealing ring assembly, characterized in that it forms a raised sliding surface (23) on the overlap region (12) .   2. The piston rod sealing ring assembly according to claim 1, wherein the sealing ring (10) and the connecting element (15) form an airtight sealing joint.

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