JP3474963B2 - Underwater bearing seal structure - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to sewage and sewage in a submerged bearing portion of a sedimentation basin in a sewage treatment plant, a sedimentation scraper installed in a sedimentation area, a sludge scraper, etc. The present invention relates to a seal structure for an underwater bearing that double-prevents foreign matter from entering therein and seals the bearing more reliably and watertightly. A sedimentation basin in a sewage treatment plant, a sediment scraper installed in the sedimentation basin, and a sludge scraper are used to extend an endless chain along the pond bottom and near the water surface in the longitudinal direction of the pond. This endless chain is engaged with a sprocket wheel that is rotatably supported on a plurality of shafts, and a flight or V bucket is attached to the endless chain at predetermined intervals, and the flight or V bucket is driven by driving the chain. The sand is moved along the bottom of the pond, and the sediment and sludge settled on the bottom of the pond are swept up and lifted to discharge out of the pond. A rotating body such as a sprocket wheel rotatably supported on a shaft disposed in the sewage is usually supported as shown in FIGS. This is provided with collars on both sides of the sprocket wheel that is rotatably fitted to the underwater shaft,
An oil seal type (see FIG. 6) in which an oil seal O is fitted to a boss portion of the sprocket wheel, and collars are provided on both sides of a sprocket wheel that is rotatably fitted to an underwater shaft. There is a seal type (see FIG. 7) in which one ring-shaped seal groove is formed and a ring seal is fitted in this groove. [0003] In the seal of a rotating body such as a sprocket wheel disposed in sewage, in an oil seal type in which an oil seal O is fitted to a boss portion of the sprocket wheel, foreign matter is present. If the sleeve or bush fitted on the outer periphery of the underwater shaft is worn by sliding during use in mixed sewage, the axis of the sleeve or bush is shifted, and a gap is formed on the lip surface of the seal. In this gap, the sealing performance rapidly decreases. Further, in a seal type in which one ring-shaped seal groove is formed on the inner surface of the collar and a ring seal is fitted into this groove, foreign matter easily enters the seal surface, and the sealing effect is not sufficient. Therefore, in order to maintain this sealing performance, lubrication is performed periodically. However, this refueling is troublesome, and the infiltration of sewage and foreign substances contained in the sewage cannot be reliably prevented. SUMMARY OF THE INVENTION An object of the present invention is to provide a seal structure for a submerged bearing which has a simple structure and reliably prevents foreign matters from entering without the need for periodic lubrication. SUMMARY OF THE INVENTION The present invention has been made to achieve the above object, and comprises a rotating body rotatably supported on an underwater shaft, and a rotating body disposed on both sides of the rotating body. A seal holding collar fixed to the underwater shaft and rotatably supporting the rotating body at a fixed position of the underwater shaft. The seal holding collar has a ring-shaped first seal groove on a sliding surface with the rotating body, and a first sealing groove. The two seal grooves are formed concentrically and of different diameters, the first ring seal is fitted to the first seal groove on the outer peripheral side, and the second ring seal is fitted to the second seal groove on the inner peripheral side under spring pressure. The gist of the present invention is that the ring seal is brought into contact with the side surface of the rotating body, and the side surface of the first ring seal is fitted into the seal fitting groove of the boss portion of the rotating body to prevent infiltration of waste water and foreign matter in the waste water. A groove for fitting the first ring seal is provided on the side surface of the boss portion of the rotating body, and the first ring seal is fitted between the grooves of the rotating body and the seal holding collar opposed thereto. As compared with the conventional abutment type, even if the shaft center shifts due to the wear of the bushing and sleeve, the sliding of the sealing surface by the first ring seal follows this shaft center shift. There is no performance degradation. Further, in the present invention, since the second ring seal is pressed against the inner peripheral side of the first ring seal against the side surface of the rotating body boss portion by spring pressure, the sealing surface is doubled, more securely sealed, Alternatively, intrusion of foreign matter in sewage is more reliably prevented. An embodiment of a seal structure for an underwater bearing according to the present invention will be described below with reference to the drawings. In the figure, reference numeral 1 denotes an underwater shaft such as a sludge scraper installed in a sand basin, a sedimentation basin or the like P in a sewage treatment plant. The rotating body 2 is rotatably supported. As shown in detail in FIG. 1, the rotating body 2 has a sleeve 3 and a bush 4 concentrically fitted on the outer periphery of the underwater shaft 1 sequentially, and fits on the outer periphery of the bush 4 and a boss portion of the rotating body. An oil reservoir 21 is formed on the inner peripheral surface of the rotor 20 so that oil can be supplied from an oil supply port 22 provided outside the rotating body. A plug 23 is detachably provided at the oil supply port, and grease sealed in the oil reservoir 21 enables long-term use. The rotating body 2 rotatably supported on the underwater shaft 1 as described above includes a seal holding collar 5 fitted on both sides of the rotating body 2 so as to rotate at a predetermined fixed position of the rotating body 1. , 5 and each of the seal holding collars 5, 5 is fixed to the underwater shaft with set bolts 51, 51. A ring-shaped first seal groove 52 and a second seal groove 53 are formed concentrically and diametrically at the position of the sliding surface with the second seal groove 20. The first ring seal 6 is fitted into the first seal groove 52 on the outer peripheral side, and the second ring seal 7 is fitted into the second seal groove 53 on the inner peripheral side under spring pressure. The first ring seal 6 is fitted into a ring-shaped seal fitting groove 24 formed on the outer surface of the rotating body boss portion 20 and slides. Make it work. The ring seal 6 fitted in the first seal groove 52 is made of a synthetic resin, and the elasticity of the ring seal 6 makes contact with the side surface of the boss portion of the rotating body with an appropriate contact pressure to perform first-stage sealing. In this case, as shown in FIG. 1, a seal fitting groove 24 into which a part of the ring seal 6 is fitted is formed on the outer surface of the rotating body boss facing the ring seal 6. Therefore, both side portions of the ring seal 6 are fitted and supported in the grooves of the rotating body and the collar, respectively. The second ring seal 7 is the first ring seal 6
However, when the second ring seal 7 is fitted into the second seal groove 53 of the seal holding collar 2, the outer surface of the second ring seal 7 projects slightly from the outer surface of the seal holding collar. The width of the second seal groove 52 is larger than the depth of the second seal groove 52. Thus, the outer surface of the second ring seal is brought into contact with the outer surface of the rotating body boss portion, and the second ring seal 7 is always brought into contact with the required pressure due to the sliding wear of the second ring seal 7. [0012] As shown in FIG.
At the bottom and at two or three locations in the circumferential direction, spring-insertion grooves 54 are provided so as to be conductive, a spring 8 is inserted into the grooves 54, and the second ring seal 7 is The boss is pressed toward the outer surface. Reference numeral 55 denotes a screw hole for screwing a set bolt. Although the illustration of the rare sand scraper is omitted, the underwater shaft and seal structure used therein are the same as those of the sludge scraper. According to the seal structure of the underwater bearing of the present invention, it is possible to easily perform the processing according to the prior art without performing complicated processing, and the displacement of the shaft center due to the wear of the bushing sleeve is reduced. Even if it occurs, the sliding of the sealing surface follows, so the sealing performance does not decrease, and the double-sided sealing structure allows long-term use of grease sealed in the oil reservoir without regular lubrication. There is an advantage that the bearing can be used and the life of the bearing can be extended.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view showing one embodiment of a seal structure of a submerged bearing of the present invention. FIG. 2 is an explanatory view of a seal holding collar of the present invention;
(A) is a sectional view, and (B) is a front view. 3A and 3B are explanatory views of a ring seal, in which FIG.
(B) is a front view. FIG. 4 is an embodiment diagram of a sludge scraper. FIG. 5 is a view showing an embodiment of a sand settling machine. FIG. 6 is a sectional view showing an embodiment of a conventional oil seal type underwater bearing structure. FIG. 7 is a sectional view showing an example of a conventional ring seal type underwater bearing structure. 8A and 8B are explanatory views of a collar of the ring seal type underwater bearing of FIG. 7, in which FIG. 8A is a sectional view and FIG. 8B is a front view. [Description of Signs] 1 Underwater shaft 2 Rotating body 20 Boss 24 Seal fitting groove 3 Sleeve 4 Bush 5 Seal holding collar 52 First seal groove 53 Second seal groove 54 Spring insertion groove 6 First ring seal 7 Second Ring seal 8 Spring

Claims (1)

(57) [Claims 1] A rotating body rotatably supported on an underwater shaft,
A seal holding collar disposed on both sides of the rotating body, fixed to the underwater shaft, and rotatably supporting the rotating body at a fixed position of the underwater shaft; and a sliding surface of the seal holding collar with the rotating body. A ring-shaped first seal groove and a second seal groove are formed concentrically of different diameters, the first ring seal is formed on the first seal groove on the outer peripheral side, and the second seal groove is formed on the inner peripheral side under spring pressure. The second ring seals are fitted respectively, the second ring seals are brought into contact with the side of the rotating body, and the side faces of the first ring seal are fitted into the seal fitting grooves of the rotating body boss to infiltrate sewage and contaminated water. A seal structure for a submerged bearing, characterized in that the seal structure is adapted to prevent the occurrence of a seal.