JPH0225015Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a sealing device for a piston rod, which is a type of shaft sealing device.

[Conventional technology]

2. Description of the Related Art Conventionally, as an example of this type of seal, seals shown in FIGS. 9 to 13, which are used in marine diesel main engines, have been known. This sealing device seals a piston rod 4 that vertically passes through a partition wall 3 that partitions a crank chamber 1 and a scavenging air chamber 2 of a diesel main engine, and seals lubricating oil in the crank chamber 1 and maintains airtightness of the scavenging air chamber 2. Its main purpose is as follows.

That is, in FIG. 9, reference numeral 5 designates a housing that is airtightly attached to the hole 3a of the partition wall 3 via a pedestal 6, and there are eight annular flanges corresponding to the inner diameter of the housing 1, which is divided into two upper and lower halves. 7
... and seven annular spaces 8... are provided, and two oil scrapers 9,
9, two airtight rings 11, 11 are installed in each of the three spaces 8 on the side of the scavenging chamber 2. As shown in FIGS. 10 and 11, the oil scraper ring 9 is
Metal arc-shaped divided body 9 divided into three in the circumferential direction
a, 9a, 9a are tightly connected in an annular manner by a garter spring 10, and an oil drain hole 9d is bored from the groove 9b formed on the inner diameter surface of each divided body 9a to the recess 9c formed on the outer peripheral surface, and the adjacent divided bodies body 9
The joint cuts 9e and 9e of the joints a and 9a are formed into flat surfaces extending in the radial direction. The airtight ring 11 is the first
As shown in FIG. 2 and FIG.
1a and 11a are tightly connected in an annular manner by a garter spring 12, and a groove 11b is formed in the inner diameter surface of each divided body 11a, and the divided bodies 11 adjacent to each other are
The joint cuts 11c, 11c of the joints 11a, 11a are formed in planes diagonal to the radial line.

[Problem that the invention attempts to solve]

The sealing device having the above structure scrapes off the lubricating oil in the crank chamber 1 adhering to the surface of the piston rod 4 with the oil scraping ring 9 when the piston rod 4 reciprocates up and down, and drains it into the oil drain hole 9d and the space 8. The lubricating oil is returned to the crank chamber 1 through the set oil reservoir 13... and the oil return hole 14... drilled in the housing 5, and the lubricating oil that has passed through the oil scraper ring 9 at the top stage is taken out of the engine from the recovery port 15 as leaked oil. On the other hand, the airtightness of the scavenging chamber 2 is maintained by the airtight rings 11, but according to this conventional device, the grooves 9 on the inner diameter surface of each ring 9, 11 that come into sliding contact with the circumferential surface of the piston rod 4
Because the parts other than b and 11b are formed flat, the sealing performance is not sufficient, and lubricating oil leaks frequently.As a countermeasure, a separate oil leakage collection and cleaning device was installed onboard the ship to reduce the consumption of lubricating oil. The reality is that we are preventing this.

The present invention has been made in view of the above points, and provides a sealing device for a piston rod that improves the sealing performance of each ring and further reduces the number of ring stages to reduce the size and weight of the entire device. It is something.

[Means for solving problems]

In order to achieve the above object, the sealing device of the present invention uses a resin-based material for the oil-scraping ring and the air-tight ring.
It is made of non-metallic material such as rubber or carbon material, and a sealing material such as an O-ring is fitted to at least one of the axial end surfaces of each ring, and the inner diameter sliding surface of each ring is connected to the crank chamber side and scavenging air. A close tip with a substantially V-shaped cross section is formed by tapered surfaces extending from the chamber side and inclined in opposite directions, and the taper angle β on the crank chamber side of the close tip of the oil scraper ring is equal to the taper angle α on the scavenging chamber side. It is characterized in that the taper angle β' of the tight tip of the airtight ring on the scavenging chamber side is larger than the taper angle α' on the crank chamber side.

[Effect]

The above-mentioned sealing device increases the contact pressure by press-contacting the close contact tip formed on the inner diameter sliding surface of each divided body to the circumferential surface of the piston rod, suppresses sliding wear by changing the material, and fits into the ring end surface. An O-ring securely seals between each ring and the housing. The close tip of the oil scraper ring has a taper angle of β>α on both sides, and the close tip of the airtight ring has a taper angle of β′>α′ on both sides, so when the piston rod moves toward the scavenging chamber, The contact force of the oil scraper ring increases and scrapes off oil from the surface of the rod, while the sliding resistance of the airtight ring decreases, and when the piston rod moves toward the crank chamber, the contact force of the airtight ring increases. While maintaining good airtightness with respect to the scavenging chamber, the sliding resistance of the oil scraper ring is reduced.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

In FIG. 1, the inner diameter of the housing 16 is 6.
One annular flange 17... and five annular spaces 18...
A total of four oil scraping rings 19 and three airtight rings 22 are installed in the space 18.

As shown in FIGS. 2 to 4, the oil scraper ring 19 is made by connecting arc-shaped divided bodies 19a, 19a... made of a non-metallic material into a required number of parts in the circumferential direction in an annular manner by means of a garter spring 20. A groove 19b is formed in the center of the inner diameter surface of each divided body 19a, and close contact tips 19c, 19c with a V-shaped cross section and tapered surfaces such that ∠β>∠α are formed at the sliding contact portions on both sides of the groove 19b,
A groove 19d is formed on the end face on the ∠β side to form the O-ring 21.
A notch 19e for oil drainage is formed on the opposite end surface, and joint cuts 19f, 1 of the adjacent divided bodies 19a, 19a are fitted.
9f is formed in a step shape in the circumferential direction as shown in the figure. As shown in FIGS. 5 to 7, the airtight ring 22 is constructed by connecting arc-shaped divided bodies 22a, 22a, etc. made of non-metallic materials into a required number in the circumferential direction in an annular manner by means of a garter spring 23. A groove 22b is formed in the center of the inner diameter surface of the divided body 22a, and close contact tips 22c, 22 having a substantially V-shaped cross section are provided with tapered surfaces such that ∠β'>∠α' at the sliding contact portions on both sides of the groove 22b.
grooves 22d, 22d are formed on both end faces to fit sealing materials such as O-rings 24, 24, and joint cuts 22e, 22e of adjacent divided bodies 22a, 22a are formed as shown in the figure. It is formed into a step shape in the circumferential direction, and further, recesses 22f, 22f are formed on the outer periphery of the joint portion, and an arc-shaped cover ring 25 is fitted into the recesses 22f, 22f.

According to the above configuration, when the piston rod 4 moves toward the scavenging chamber 2 side, the close contact force of the close contact tip 19c of the oil scraper ring 19 increases, and while the lubricating oil adhering to the surface of the rod 4 is scraped off, the air tight ring 2
When the sliding resistance of the close contact tip 22c of the airtight ring 22 becomes small, and when the piston rod 4 moves toward the crank chamber 1 side, the close contact force of the close contact tip 22c of the airtight ring 22 increases, and the airtightness with respect to the scavenging chamber 2 is improved. While holding, the close tip 19 of the oil scraper ring 19
Since the sliding resistance of c is reduced, the sealing performance can be improved without increasing the sliding resistance as a whole. Moreover, since both rings 19 and 22 are made of non-metallic materials, the frictional resistance is reduced compared to conventional metal ones, and sliding wear of the rings 19 and 22 can be suppressed.
By fitting sealing materials such as Nos. 1 and 24, it is possible to improve the sealing force of the portion. Further, in each ring 19, 22, the joint cuts 19f, 19f, 22e, 22e of the mutually adjacent arc-shaped divided bodies 19a, 19a, 22a, 22a are formed in a step shape in the circumferential direction, and the cover ring 2
5, the gap at the joint can be narrowed or closed, and leakage from the joint can be suppressed. In addition, if each ring 19, 22 is made of a highly elastic material such as Teflon or rubber, each ring 19, 22 can be formed into one annular body, and the cut end can be cut into one ring.
It only needs to be installed at a certain point, and it has great benefits in terms of improving sealing performance and reducing processing costs. FIG. 8 is characterized in that ring supporting metal fittings 26 are provided between each ring 19, 22 and the housing 16, which facilitates ring assembly (insertion) and improves the sealing performance of the O-rings 21, 24. This is what we are trying to achieve.

[Effect of idea]

As explained above, the piston rod sealing device of the present invention has a substantially V-shaped cross section in which the internal sliding surfaces of the required number of oil scrapers and air seal rings, each arranged in parallel, are made up of tapered surfaces that intersect with each other at different angles. By creating a close contact point, the sealing performance can be improved without increasing the overall sliding resistance, and this can improve the overall performance.
In line with the improvement in performance, the number of ring stages can be reduced and a compact and lightweight device can be provided, and the practical effects of the present invention are extremely large.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of a piston rod sealing device according to an embodiment of the present invention, Fig. 2 is a half-cut sectional view of an oil scraper ring according to the same embodiment, Fig. 3 is a side view of the same part, and Fig. 4 is a FIG. 5 is a half-cut sectional view of the airtight ring according to the same embodiment, FIG. 6 is a side view of the same portion, and FIG. 7 is a partially developed view of the ring viewed from the inside diameter direction. , FIG. 8 is a cross-sectional view of a piston rod sealing device according to another embodiment of the present invention, FIG. 9 is a cross-sectional view of a piston rod sealing device according to a conventional example, and FIG. 10 is an oil scraper ring according to the conventional example. 11 is a side view of the same, FIG. 12 is a half-cut sectional view of the airtight ring according to the conventional example, and FIG. 13 is a side view of the same. 1... Crank chamber, 2... Scavenging chamber, 3... Partition wall, 4... Piston rod, 5, 16... Housing, 7, 17... Flange, 8, 18... Annular space, 9, 19... Oil Scratching, 10, 12, 2
0,23...Gata spring, 11,22...
Airtight ring, 13...Oil reservoir, 14...Oil return hole, 15...Recovery port, 19a, 22a...Circular segment, 19c, 22c...Close tip, 19e...
...Notch, 19f, 22e...Cut, 21, 24...
...O-ring, 25...Cover ring.

Claims (1)

[Scope of utility model registration request] In a piston rod sealing device comprising a required number of oil-scraping rings on the crank chamber side and air-tight rings on the scavenging chamber side, each of which is formed by annularly connecting a plurality of arcuate segments divided in the circumferential direction, each ring is made of resin. A sealing material such as an O-ring is fitted to at least one of both end faces in the axial direction of each ring, and a crank chamber is formed on the inner diameter sliding surface of each ring. A close tip with a substantially V-shaped cross section is formed by tapered surfaces extending in opposite directions from the side and the scavenging chamber side, and the taper angle β of the close tip of the oil scraper ring on the crank chamber side is equal to greater than the taper angle α,
The sealing device for a piston rod is characterized in that a taper angle β' on the side of the scavenging chamber of the tight tip of the airtight ring is larger than a taper angle α' on the side of the crank chamber.