Bearing mechanism with lubrication device

Abstract

The present invention provides a bearing mechanism that can be used for a long period of time even in environments where a load perpendicular to the axis of rotation is constantly applied, and where fine solid droplets of water are constantly falling from above. [Solution] A bearing mechanism 20 equipped with an oiling device 30 rotatably supports an immersion roll 3 used in an environment where an endless filter cloth belt B is stretched over it, subjecting it to a constant radial load and to falling water droplets containing fine solid particles. The mechanism consists of a rolling bearing section 21, a bearing housing 26 made of a pillow block or plummer block that houses the rolling bearing section 21, and an oiling device 30 that oils the rolling bearing section 21 through an oiling port 26a of the bearing housing 26, wherein the gap of the seal section 25 that seals the rolling elements 24 of the rolling bearing section 21 is sealed with the grease.

Description

Technical Field

[0001] The present invention relates to a bearing mechanism provided with an oil injection device, and particularly to a bearing mechanism provided with an oil injection device that rotatably supports a roll over which an endless belt of a filter cloth belt type dehydrator is spanned.

Background Art

[0002] Filter cloth belt type dehydrators are used in various fields such as metal smelting, petrochemical industry, and wastewater treatment. For example, in zinc smelting, in the wet cleaning process of crude zinc oxide obtained by subjecting steel dust to reduction roasting treatment, after the crude zinc oxide is repulped and washed to remove impurities such as fluorine, the slurry containing the washed crude zinc oxide is dehydrated using a filter cloth belt type dehydrator. This filter cloth belt type dehydrator is a device that dehydrates by squeezing a slurry supplied onto an endless filter cloth belt together with the filter cloth belt by a pair of rolls, and the filter cloth belt is configured to circulate along a path defined by a plurality of rolls. These plurality of rolls are required to have durability to continuously rotate stably over a long period of time, and therefore, a bearing mechanism suitable for the use environment is selected for each roll.

[0003] For example, Patent Document 1 relates to a bearing mechanism of a rotating shaft provided with a dehydrating cage such as a washing machine at its upper end. It discloses a technique in which an oil seal is installed in a shaft holder provided at the bottom of a tank and a bearing made of synthetic resin is installed inside the tank on the inner side of the oil seal. By using the bearing of this Patent Document 1, it is described that the oil seal can be protected from thread waste and the problem of water leakage due to damage to the oil seal of the bearing required to support the rotating shaft watertightly can be prevented.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

[0005] The bearing disclosed in Patent Document 1 above rotatably supports a rotating shaft that extends in the vertical direction, and therefore the bearing is subjected to an axial (thrust) load mainly parallel to the direction of the rotating shaft. In contrast, the rolls used in a filter cloth belt type dewatering machine have rotating shafts that extend in the horizontal direction, and the filter cloth belt is constantly under tension in the direction of travel, so the bearing mechanism of the roll is subjected to a radial load perpendicular to the direction of the rotating shaft.

[0006] Furthermore, in a filter cloth belt type dewatering machine, after recovering the wet cake obtained by compressing with the pair of rolls described above, the filter cloth belt is cleaned by immersing it in washing water or by spraying washing water onto the filter cloth belt. Since these cleanings are usually performed while the filter cloth belt is traveling at the lowest point of its path, the bearing mechanism supporting the lowest roll among the multiple rolls that define the path of the filter cloth belt is used in an environment where it is likely to be hit by water droplets from the washing water splashed during cleaning, or water droplets formed by leakage of slurry or filtrate supplied to the filter cloth belt traveling in the upper path.

[0007] The aforementioned water droplets may contain fine solid particles such as zinc oxide, which are the material to be dewatered in a filter cloth belt type dewatering machine. If these water droplets penetrate the inside of the bearing mechanism, there is a risk of significant wear on the bearing mechanism. If the wear of the bearing mechanism progresses to the point of failure, in the case of metallic zinc smelting, it will be necessary to stop the wet cleaning process, disassemble and inspect the bearing mechanism, and repair or replace it with a new one, which will have a significant negative impact on productivity. This invention has been made in view of the above circumstances, and aims to provide a bearing mechanism that can be used stably for a long period of time even in an environment in which a load perpendicular to the rotation axis is constantly applied and water droplets containing fine solid particles are constantly falling mainly from above. [Means for solving the problem]

[0008] To achieve the above objective, the bearing mechanism equipped with an oiling device according to the present invention is a bearing mechanism equipped with an oiling device that rotatably supports a roll used in an environment in which an endless belt is stretched over it, thereby subjecting it to a constant radial load and to falling water droplets containing fine solid particles, and comprises a rolling bearing section, a bearing housing consisting of a pillow block or plummer block that houses the rolling bearing section, and an oiling device that supplies grease to the rolling bearing section through the oiling port of the bearing housing, wherein the gap in the sealing section that seals the rolling elements of the rolling bearing section is sealed with the grease. [Effects of the Invention]

[0009] According to the present invention, it becomes possible to use the device for a long period of time even in environments where a load perpendicular to the rotation axis is constantly applied and fine solid droplets of water are constantly falling from above. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic side view of a filter cloth belt type dewatering machine to which the bearing mechanism equipped with the lubrication device of the present invention is preferably applied. [Figure 2] This is a partially cut-out perspective view of a specific example of a bearing mechanism equipped with a lubrication device according to the present invention. [Figure 3] This is a perspective view of a specific example of a bearing housing in a bearing mechanism equipped with a lubrication device according to the present invention. [Figure 4] This is a cross-sectional view of the rolling bearing portion of the bearing mechanism shown in Figure 2. [Figure 5] A perspective view showing a bearing mechanism equipped with a lubrication device according to an embodiment of the present invention, with a waterproof cover provided. [Figure 6] A side view showing a bearing mechanism equipped with a lubrication device according to an embodiment of the present invention, with a waterproof cover provided. [Modes for carrying out the invention]

[0011] 1. Filter cloth belt type dehydrator First, a specific example of a filter cloth belt type dewatering machine in which the bearing mechanism equipped with the lubrication device according to the present invention is suitably used will be described with reference to Figure 1. In the filter cloth belt type dewatering machine shown in Figure 1, the filter cloth belt B, which is an endless belt made of a liquid-permeable material such as felt, is stretched over three rolls: a lower squeeze roll 1, a lower press roll 2 located slightly diagonally below and downstream of the lower squeeze roll 1, and an immersion roll 3 located below the lower squeeze roll 1 and the lower press roll 2, thereby defining a roughly inverted triangular travel path. Note that the number of rolls defining the travel path of the filter cloth belt B is not limited to the three mentioned above, and for example, a tension roll that applies a certain tension to the filter cloth belt B or a guide roll that defines a travel path other than the roughly inverted triangle may be provided.

[0012] An upper squeeze roll 4 is provided directly above the lower squeeze roll 1, with a filter cloth belt B in between, and an upper press roll 5 is provided directly above the lower press roll 2, with a filter cloth belt B in between. Upstream of the slightly inclined first path from the lower squeeze roll 1 to the lower press roll 2, raw material slurry is supplied from a stirring tank 6, where raw material slurry is stored after being stirred by an agitator, via a supply pipe 6a and a liquid dispersion means 7, which is, for example, a roughly fan-shaped inclined surface in plan view.

[0013] Behind the filter cloth belt B, which travels along the first path described above, is a dewatering section 8, which maintains a negative pressure state with a suction pump (not shown). As the filter cloth belt B slides over the opening of the dewatering section 8, the raw material slurry conveyed by the filter cloth belt B is gradually dewatered as its moisture is drawn through the filter cloth belt B by suction. The moisture that has passed through the filter cloth belt B is collected as filtrate in the dewatering section 8 and then recovered into the filtrate tank 9 via the extraction pipe 8a.

[0014] The raw material slurry, concentrated by suction from the dewatering unit 8 described above, is compressed by being sandwiched between the lower press roll 2 and the upper press roll 5 together with the filter cloth belt B. The wet cake generated by this compression is transferred from the filter cloth belt B to the outer surface of the upper press roll 5, and then scraped off by a scraper 10 whose tip contacts the outer surface. The wet cake thus scraped off falls by gravity and is guided by the chute 11 to be collected in the container C.

[0015] The filter cloth belt B, which has been inverted by the lower press roll 2, passes through the immersion roll 3, which is partially submerged in the cleaning water in the cleaning water tank 12, before returning to the lower squeeze roll 1. In this way, the filter cloth belt B is cleaned by temporarily traveling through the cleaning water in the cleaning water tank 12. In this second path from when it is inverted by the lower press roll 2 until it returns to the lower squeeze roll 1, there are further spray nozzles 13 positioned opposite the front and back surfaces of the filter cloth belt B, and the filter cloth belt B is further cleaned by spraying cleaning water from these spray nozzles 13.

[0016] 2. Bearing mechanism equipped with lubrication device Next, a bearing mechanism equipped with an oiling device according to an embodiment of the present invention that rotatably supports the immersion roll 3 in the above-described filter cloth belt type dewatering machine will be explained. As described above, among the multiple rolls that define the travel path of the filter cloth belt B, the immersion roll 3 is located at the lowest position, so the bearing mechanism 20 that rotatably supports the immersion roll 3 is constantly subjected to an upward load (radial load) due to the tension in the travel direction of the filter cloth belt B. Furthermore, the immersion roll 3 is in an environment where it is subjected to splashes of washing water from the washing water tank 12 and the spray nozzle 13, as well as water droplets of raw material slurry and filtrate leaking from the filter cloth belt B traveling along the upper first path.

[0017] Therefore, the bearing mechanism 20 of the embodiment of the present invention that rotatably supports the dipping roll 3 is composed of a rolling bearing portion 21, a bearing box 26 that houses the rolling bearing portion 21, and a lubricating oil injection device 30 that injects grease into the rolling bearing portion 21 within the bearing box 26. Specifically described, as shown in FIG. 2, the rolling bearing portion 21 is preferably externally fitted to the rotating shaft 3a of the dipping roll 3 via a sleeve, and includes an inner ring 22 that rotates together with the rotating shaft 3a, an outer ring 23 that is fixed to the inside of the bearing box 26, a plurality of rolling elements 24 that are rotatably held between the inner ring 22 and the outer ring 23 and are arranged at equal intervals in the circumferential direction, and a seal portion 25 such as a labyrinth seal or an oil seal that prevents a large amount of grease injected by the lubricating oil injection device 30 between the inner ring 22 and the outer ring 23 from leaking out externally or, conversely, prevents foreign matter, moisture, etc. from entering between the inner ring 22 and the outer ring 23 from the outside. As shown in FIG. 2, the above-mentioned rolling elements 24 may be spherical balls or columnar or frustum-shaped rollers (rollers).

[0018] The bearing box 26 that houses the above-mentioned rolling bearing portion 21 may be a pillow block having an integral structure as shown in FIG. 3(a) (also referred to as an insert bearing unit), or a plummer block that can be divided into upper and lower parts with a horizontal plane having a central axis as a boundary. In either case, an oil injection port 26a for injecting grease into the rolling elements 24 of the rolling bearing portion 21 is preferably provided at the top of the bearing box 26. A grease nipple is screwed into this oil injection port 26a, and grease is injected from the lubricating oil injection device 30 through an oil injection pipe 31 connected to this grease nipple.

[0019] As the lubricating oil injection device 30, for example, a grease gun that injects grease by operating a lever to reciprocate a plunger at the tip by filling grease in a cylindrical oil cylinder can be preferably used. When injecting grease by this lubricating oil injection device 30, as shown in FIG. 4, in addition to filling the space between the inner ring 22 and the outer ring 23 of the above-mentioned rolling bearing portion 21 with grease, the gap of the preferably non-contact seal portion 25 that plays a role in sealing the rolling elements 24 of the above-mentioned rolling bearing portion is filled with grease by excessively injecting grease so that the grease protrudes to the outside.

[0020] With the above configuration, the communication between the inside and the outside of the rolling bearing portion 21 is blocked by hydrophobic grease that repels moisture, so that it is possible to reliably prevent moisture containing fine solid components from entering the inside of the rolling bearing portion 21. As a result, wear of the rolling bearing portion 21 due to solid components is almost eliminated, and even under harsh conditions where water droplets containing fine solid components constantly fall mainly from above and a radial load is constantly applied to the immersion roll 3 supported by the rolling bearing portion 21, the filter cloth belt B can be stably run for a long period of time.

[0021] That is, conventionally, resin sliding bearings are often used for bearings that rotatably support a roll used in an environment where water droplets containing fine solid components constantly fall mainly from above, such as the immersion roll 3. In this case, since it is made of resin, corrosion problems are less likely to occur. However, moisture containing the fine solid components enters between the sliding bearing and the rotating shaft, and the sliding bearing rapidly wears due to the fine solid components, which has been a problem.

[0022] In particular, for the roll used in the filter cloth belt type dehydrator, a load is applied in the radial direction due to the tension of the filter cloth belt. In the case of the immersion roll located at the lowermost part, an upward force is applied to the rotating shaft. Therefore, a slight gap is likely to occur between the bearing and the lower side of the rotating shaft on the opposite side, and moisture containing the above-mentioned fine solid components is likely to enter this gap. And once the fine solid components enter between the bearing and the rotating shaft, rapid wear progresses because a radial load is applied to this bearing.

[0023] In contrast, the bearing mechanism equipped with the lubrication device of the embodiment of the present invention, having the above structure, can suppress the occurrence of bearing wear problems caused by water droplets containing fine solid particles. It is preferable to confirm that the gap of the seal portion 25 is sealed with grease by visual inspection, for example, at a frequency of about once a day. If, as a result of this inspection, the grease in the gap of the seal portion 25 of the rolling bearing portion 21 has been at least partially lost due to physical force caused by slurry containing solid particles being scattered from the surroundings, the lubrication device 30 should be operated to replenish the grease as appropriate, thereby sealing the gap of the seal portion 25 of the rolling bearing portion 21 with grease again. If the seal portion 25 is composed of two or more seal mechanisms, it is preferable that the gap of the outermost seal mechanism is sealed with grease as described above, from the viewpoint of ease of visual inspection.

[0024] In the bearing mechanism equipped with the lubrication device of this embodiment of the present invention, a particularly remarkable effect is obtained when the fine solid components contained in the water droplets falling mainly from above are metal oxides or metal nitrides. This is because these metal compounds have particularly high hardness, and if they penetrate between the bearing and the rotating shaft, they significantly accelerate the wear of both.

[0025] In the bearing mechanism of the present invention, it is preferable that the bearing housing 26 is provided with a waterproof cover 27 so as to cover the upper part of the seal portion 25. The shape of the waterproof cover 27 and the method of providing the waterproof cover 27 are not particularly limited as long as they can more reliably prevent water droplets containing fine solid matter from entering the rolling bearing portion 21 through the gap in the seal portion 25. However, as shown in Figures 5 and 6, it is preferable to attach a curved awning-like member, such as those provided above the red, blue, and yellow lamps of a traffic signal, by welding or bolts and nuts. [Examples]

[0026] Using a filter cloth belt type dewatering machine as shown in Figure 1, a slurry containing zinc oxide, a type of metal oxide, as a solid component at a solid content concentration of 650-800 g / L was dewatered to produce a moist cake with a moisture content of 18-25% at a production rate of 150-200 tons per day, including moisture. In this process, the bearing mechanism of the immersion roll 3 consisted of a rolling bearing section 21 and a pillow block type bearing housing 26 that housed it. The bearing housing 26 was equipped with an oiling device 30 consisting of a grease gun via an oiling pipe 31 connected to its oiling port 26a. Furthermore, waterproof covers 27 made of curved metal plates were welded to both sides of the bearing housing 26 to prevent slurry containing solid components, which mainly falls from above, from entering the rolling bearing section 21.

[0027] Thus, the slurry dewatering operation of the embodiment was continued for six months under conditions in which slurry droplets fell onto the immersion roll 3 from above, and an upward radial load was constantly applied due to the tension of the filter cloth belt B. During this time, the gaps in the seal portion that seals the rolling elements of the rolling bearing portion 21 were allowed to leak outwards, thereby maintaining a state in which the gaps were sealed with grease. After the completion of this six-month dewatering operation of the embodiment, the bearing mechanism was visually inspected and no wear was observed at all.

[0028] For comparison, a slurry dewatering operation was performed in the same manner as in the above embodiment, except that a resin sliding bearing was used in place of the rolling bearing in the bearing mechanism of the immersion roll 3. As a result, after 2.5 months from the start of the dewatering operation, one side of the resin sliding bearing that was subjected to the radial load almost completely disappeared due to wear, making it necessary to stop the dewatering operation. [Explanation of Symbols]

[0029] 1. Lower squeeze roll 2. Lower press roll 3 Immersion Roll 4. Upper squeeze roll 5. Upper press roll 6. Agitation tank 6a Supply pipe 7 Liquid dispersion means 8 Dehydration section 8a Extraction tube 9 Filtrate tank 10 Scrapers 11 shots 12 Washing water tank 13 Spray nozzles 20 Bearing mechanism 21 Rolling bearing section 22 Inner Ring 23 Outer ring 24 Rolling elements 25 Seal part 26 Bearing housing 26a Oil filler port 27 Waterproof cover 30 Lubricating device 31 Oil supply pipe B Filter cloth belt C container

Claims

1. A bearing mechanism equipped with a lubrication device that rotatably supports a roll used in an environment where an endless belt is stretched across it, subjecting it to constant radial load and to falling water droplets containing fine solid particles, A bearing mechanism comprising a rolling bearing section, a bearing housing consisting of a pillow block or plummer block housing the rolling bearing section, and a lubrication device for supplying grease to the rolling bearing section through the lubrication port of the bearing housing, wherein the gap in the seal section that seals the rolling elements of the rolling bearing section is sealed with the grease.

2. The bearing mechanism equipped with the lubrication device according to claim 1, characterized in that the belt is a filter cloth belt of a filter cloth belt type dewatering machine.

3. A bearing mechanism equipped with a lubrication device according to claim 2, characterized in that the solid content is a metal oxide or a metal nitride.

4. A bearing mechanism equipped with a lubrication device according to any one of claims 1 to 3, characterized in that the bearing housing has a waterproof cover that covers the upper part of the seal portion.

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