Patent Application
20190360597
The present invention relates to a sealing device for a bearing housing (a plummer block) in which a self-aligning rolling bearing is arranged used for a general industrial machine.
A bearing housing is called a bearing box or a plummer block, and the bearing housing is widely used for a general industrial machine as a bearing unit combined with a rolling bearing arranged in the bearing housing. Examples of the general industrial machine to which the bearing housing is applied, include vehicles, construction machines, machine tools, gear devices, conveyance devices, air conditioning facilities, mine facilities, power generation facilities in various fields. For example, in a mine, the plummer block that holds a bearing, which supports a rotational shaft of a conveyor roller at both sides of a belt conveyor that conveys iron ore or coal from a stope to a loading place to trucks, is used. Further, in an iron mill, the bearing housing is used in a bearing for a rolling mill roll neck.
In order to prevent dust or water from entering into an inner sealed space in which the rolling bearing is arranged and in order to prevent a lubricant from being leaked, a sealing device is adopted in the bearing housing. As the sealing device for the bearing housing, a contact seal such as a rubber seal, a felt seal, and a rubber seal with a spring, a labyrinth seal in which a small gap space is formed in a labyrinth manner, a grease seal filled with grease, or a seal structure combining several seals thereof is adopted in accordance with the usage. Especially, in an environment in which much fine dust is apt to be scattered such as in a mine, an iron mill and a power plant, or in an environment in which rain water or cooling water pours, a configuration of the sealing device is significant, and a seal having high sealing performance that combines a plurality kinds of seals is adopted.
Conventionally, Patent Document 1 proposes a sealing device for a bearing housing in such a usage. A configuration of the sealing device is described with reference to
Patent Document 1: U.S. Pat. No. 5,904,356 B
In the configuration shown in
In a case in which many bearings are installed over along range, for example, in a mine or an iron mill, it is required to make a maintenance interval of the bearing unit as long as possible from a viewpoint of reducing a maintenance cost. Thus, it is required to eventually prevent the dust from entering into the inner sealed space of the bearing housing. Further, in order to avoid deterioration of sealing performance due to the wear of the members described above, it is also required to prevent the dust from entering into the sealing passage such as the labyrinth portion formed between the fixed member and the rotating member.
An object of the present invention is, in order to solve such a problem, to provide a sealing device for a bearing housing capable of preventing or suppressing entering of dust into an inner sealed space of the bearing housing and into a sealing passage such as a labyrinth portion.
A sealing device for a bearing housing of the present invention is formed as a sealing device for a bearing housing in which a rolling bearing that supports a rotation shaft is arranged. The sealing device includes a fixed member fixed to the bearing housing, a rotating member fixed to the rotation shaft, and a labyrinth portion formed by surfaces of the fixed member and the rotating member arranged to face each other with a gap. The labyrinth portion is formed such that a gap width of an inlet portion of the sealing device to an inner sealed space of the bearing housing from an outside is smaller than a gap width of a portion other than the inlet portion. The labyrinth portion includes an inclined space portion that is not orthogonal to and is not parallel to the rotation shaft in a region between a portion at a side of the inner sealed space and the inlet portion.
The sealing device includes, in a sealing passage at the side of the inner sealed space with respect to the labyrinth portion, a seal ring labyrinth portion formed by a gap between a seal ring fixed to the rotating member and the fixed member, and a grease seal portion formed by a space between the fixed member and the rotating member filled with grease, the space having a gap width larger than the gap width of the labyrinth portion. Further, the sealing device includes, in the sealing passage at the side of the inner sealed space with respect to the labyrinth portion, a contact seal portion formed by a felt or an O-ring.
The sealing device includes an oil supply plug, and a grease groove for transmitting the grease supplied from the oil supply plug to the labyrinth portion. The grease groove is connected to a portion adjacent to an end portion of the inclined space portion, at a side of the inlet portion.
The sealing device includes a bristle portion formed by fiber flocked on at least one of surfaces of the rotating member and the fixed member, the bristle portion being formed in at least a part of the labyrinth portion formed by the rotating member and the fixed member. Further, the bristle portion is formed at the inlet portion in the labyrinth portion.
The bristle portion is formed by fiber flocked on an outer surface of the fixed member around an inlet to the inner sealed space of the bearing housing from the outside.
Further, the fiber is formed of synthetic resin, and the bristle portion is formed as an electrostatically flocked portion.
The sealing device for the bearing housing of the present invention includes the fixed member fixed to the bearing housing, the rotating member fixed to the rotation shaft, and the labyrinth portion formed by the surfaces of the fixed member and the rotating member arranged to face each other with a gap. In the labyrinth portion, since the gap width of the inlet portion of the sealing device to the inner sealed space of the bearing housing from the outside is smaller than the gap width of the portion other than the inlet portion, a sectional area of the inlet portion of the labyrinth portion to which dust is entered firstly from the outside is smaller than a sectional area of an inner portion. Consequently, entering of dust can be suppressed, and even if the dust is entered, the dust can be restricted to small size dust. Further, volume (size) of the sealing device can be reduced.
Further, since the labyrinth portion includes the inclined space portion that is not orthogonal to and is not parallel to the rotation shaft in the region between the portion at the side of the inner sealed space and the inlet portion, a pressure difference from the inner side toward the outer side can be caused in the inclined space portion by centrifugal force generated by the rotating member and thereby entering of dust can be suppressed.
The sealing device includes, in the sealing passage at the side of the inner sealed space with respect to the labyrinth portion, the seal ring labyrinth portion formed by the gap between the seal ring fixed to the rotating member and the fixed member, and the grease seal portion formed by the space between the fixed member and the rotating member filled with grease, the space having the gap width larger than the gap width of the labyrinth portion, and thereby a sealing structure with high sealing performance can be obtained. Further, the sealing device includes, in the sealing passage at the side of the inner sealed space with respect to the labyrinth portion, the contact seal portion formed by a felt or an O-ring, and thereby fine dust entered into the inside can be firmly prevented from reaching the inner sealed space of the bearing housing.
The sealing device includes the oil supply plug, and the grease groove for transmitting the grease supplied from the oil supply plug to the labyrinth portion, and the grease groove is connected to the portion adjacent to the end portion of the inclined space portion, at the side of the inlet portion. Consequently, grease and dust are extruded toward the inlet portion from both of the side of the inclined space portion and the side of the grease groove, and thereby entering of the dust can be suppressed.
The sealing device includes the bristle portion formed by fiber flocked on at least one of the surfaces of the rotating member and the fixed member, the bristle portion being formed in at least a part of the labyrinth portion formed by the rotating member and the fixed member. Consequently, a foreign object such as dust is captured by the bristle portion and thereby entering of the dust into the inner sealed space of the bearing housing can be prevented.
The bristle portion is formed by fiber flocked on the outer surface of the fixed member around the inlet to the inner sealed space of the bearing housing from the outside, and thereby a foreign object such as dust is captured by the bristle portion around the inlet to an inside of the sealing passage, and entering of the dust to the inside of the sealing passage can be suppressed.
The fiber is formed of synthetic resin, and the bristle portion is formed as the electrostatically flocked portion, and thereby swelling or dissolving of the fiber is hardly caused by oil in the grease filled in the sealing passage, and the bristle portion which is chemically stable and has the fiber flocked densely with uniform quality can be obtained.
One example of a sealing device for a bearing housing of the present invention is described with reference to
The labyrinth portion 4 is formed by a recessed surface and a projection surface of the fixed member 2 and the rotating member 3 arranged to face to each other with a gap. That is, the fixed member 2 and the rotating member 3 are positioned such that a projection of one member and a recess of another member are complementarily arranged with a gap. The labyrinth portion 4 is arranged at an outermost side of the sealing device 1 for the bearing housing in the sealing passage. An inlet portion 4a of the labyrinth portion 4 is formed as an inlet from an outside to the inner sealed space of the bearing housing 12 sealed by the sealing device 1 for the bearing housing.
The labyrinth portion 4 is formed by the inlet portion 4a as a first region, a second region 4b, an inclined space portion 4c as a third region, a fourth region 4d, and a fifth region 4e arranged in this order from a side of the inlet. Each of the inlet portion 4a as the first region and the fifth region 4e is formed as a gap space parallel to the rotation shaft 14. By forming the inlet portion 4a to be a horizontal gap space, rain water or the like is hardly entered. Each of the second region 4b and the fourth region 4d is formed as a gap space orthogonal to the rotation shaft 14. The inclined space portion 4c as the third region is a gap space that is not orthogonal and is not parallel to the rotation shaft 14. A gap width (a gap width in a radial direction) of each of the inlet portion 4a as the first region, the inclined space portion 4c as the third region, and the fifth region 4e is set to be smaller than a gap width (a gap width in an axial direction) of each of the second region 4b and the fourth region 4d.
The gap width of the inlet portion 4a as the first region is set to be smaller than a gap width of other regions in the labyrinth portion 4. The gap width is defined by a distance between surfaces of the fixed member 2 and the rotating member 3 in each region. A sectional area of the gap space having a small gap width is small. Accordingly, the sectional area of the gap space of the inlet portion 4a is smaller than the sectional area of the gap space of other region. With this, dust is hardly entered into the inlet portion 4a of the labyrinth portion 4, which is a part into which the dust is firstly entered from the outside, and even if the dust is entered into the inlet portion 4a, the dust can be restricted to small size dust. Further, a lubricant such as grease filled in the sealing passage is prevented from leaking from the inlet portion 4a.
A shape of the labyrinth portion 4 is not especially limited as long as a region having a small gap width with a resistance against a passing object such as grease and dust being large enough to suppress leaking of grease and entering of dust is arranged. As shown in
An effect of the inclined space portion 4c in the labyrinth portion 4 is described with reference to
An inclined angle of the inclined space portion 4c against a direction of the rotation shaft is not especially limited, however in order to generate the effect described above and to ensure sealing performance, the inclined angle is set in a range between 3° and 60°, more preferably a range between 40° and 50°.
Further, the grease groove 9 is formed parallel to the rotation shaft so as to be connected to a grease hole (see
As shown in
As shown in
As shown in
Each of (1) the labyrinth portion, (2) the seal ring labyrinth portion, and (3) the grease seal portion is formed as a non-contact seal portion. A combination of these seal portions (1) to (3) can ensure excellent sealing performance and therefore entering of dust or the like can be suppressed. In a case in which sufficient sealing performance can be ensured by this combination, (4) the contact seal portion can be omitted.
Other example of the sealing device for the bearing housing of the present invention is described with reference to
The sealing device for bearing housing of the present invention is mainly used to fill grease into the sealing passage in addition to the inside of the bearing housing as described above (grease lubrication). Oil lubrication may be adopted in accordance with a configuration of the bearing housing. Further, in a case in which the bearing housing is filled with the grease, an inside of a rolling bearing is filled with the grease in advance.
As base oil that forms the grease, any oil may be adopted as long as it is normally used for a plummer block. Examples of the base oil include a mineral oil such as a spindle oil, a machine oil and a turbine oil, a hydrocarbon-based synthetic oil such as a polybutene oil, a poly α-olefin oil, an alkylbenzene oil and an alkylnaphthalene oil, a natural oil and fat, a non-hydrocarbon-based synthetic oil such as a polyol ester oil, a phosphoric ester oil, a diester oil, a polyglycol oil, a silicon oil, a polyphenyl ether oil, an alkyldiphenyl ether oil and a fluorine oil. These lubricants may be used independently, or alternatively two or more of these lubricants may be used in combination. In a case in which the oil lubrication is adopted, the base oil is used as a lubricant.
Examples of thickener that forms the grease include metal soap-based thickener such as aluminum soap, lithium soap, sodium soap, lithium complex soap, calcium complex soap and aluminum complex soap, a urea compound such as a diurea compound (aliphatic diurea, alicyclic diurea, aromatic diurea or the like) and a polyurea compound, and fluororesin powder such as PTFE resin. These thickeners may be used independently, or alternatively two or more of these thickeners may be used in combination.
A known additive may be added to the lubricant as needed. Examples of the additive include an extreme pressure agent such as an organozinc compound and an organomolybdenum compound, an antioxidant such as an amine-based compound, a phenol-based compound and a sulfur-based compound, a friction suppressive agent such as a sulfur-based compound and a phosphorous-based compound, a rust preventive agent such as polyhydric alcohol ester, a viscosity index improver such as polymethacrylate and polystyrene, a solid lubricant such as molybdenum disulfide and graphite, and an oil agent such as ester and alcohol.
Other example of the sealing device for the bearing housing of the present invention is described with reference to
The labyrinth portion 15 is arranged in the sealing passage at an outermost side of the sealing device 1 for the bearing housing among the labyrinth portions 15 to 18. The labyrinth portion 15 is formed as an inlet from an outside to the inner sealed space of the bearing housing 12 sealed by the sealing device 1 for the bearing housing. The labyrinth portions 17 and 18 are arranged in the sealing passage at both ends of the grease seal portion 6 respectively. The labyrinth portion 16 is a gap space not orthogonal and not parallel to the rotation shaft 16 (inclined space portion, corresponding to the inclined space portion 4c in
In a case in which the bristle portion is formed, a sealing structure formed by the labyrinth portion is not especially limited as long as a region having a small gap width with a resistance against a passing object such as grease and dust being large enough to suppress leaking of grease and entering of dust is arranged. As shown in
In this configuration, a bristle portion 19 is formed in the labyrinth portions 15, 17 and 18. A configuration of the bristle portion 19 is described with reference to
In the configuration shown in
Further, the bristle portion may be formed in the labyrinth portion 16 similar to other labyrinth portions. It may be determined as needed that the bristle portion is formed in any labyrinth portions 15 to 18, however it is preferable that the bristle portion is formed in at least the labyrinth portion 15. As described above, the labyrinth portion 15 is formed as an inlet toward the inner sealed space of the bearing housing 12 from the outside, and therefore by forming the bristle portion in the labyrinth portion 15, the entering of dust from the outside to an inside of the sealing passage is suppressed.
Further, in
The bristle portion is formed by flocking short fiber. As a flocking method, a spraying method or an electrostatic flocking method may be adopted. The electrostatic flocking method is preferable because much fiber can be flocked vertically and densely in a short period of time even on a peripheral surface such as a surface of each member forming the labyrinth portion. As the electrostatic flocking method, a known method can be adopted, and for example a method in which coating a region to which the electrostatic flocking is applied with an adhesive, charging the short fiber, flocking short fiber approximately vertically on a surface coated by the adhesive by using electrostatic force, and then performing a drying step and a finishing step is adopted.
The short fiber used for flocking is not especially limited as long as it can be used as short fiber for flocking. Examples of the short fiber include (1) synthetic resin fiber formed of a polyolefin resin such as a polystyrene and a polypropylene, a polyamide resin such as a nylon, an aromatic polyamide resin, a polyester resin such as a polyethylene terephthalate, a polyethylene naphthalate, a polybutylene succinate, a polybutylene terephthalate, an acryl resin, a vinyl chloride, or a vinylon, (2) inorganic fiber such as carbon fiber and glass fiber, (3) regenerated fiber such as rayon and acetate, and natural fiber such as cotton, silk, hemp and wool. These fibers may be used independently, or alternatively two or more of these fibers may be used in combination. It is preferable to adopt the synthetic resin fiber among those fibers because the synthetic resin fiber is chemically stable, swelling or dissolving of the fiber is hardly caused by oil in the grease filled in the sealing passage, and fiber having uniform quality can be mass-produced and obtained at low cost.
A shape of the short fiber is not especially limited unless any negative influence affects sealing performance and bearing performance (torque or the like). For example, the fiber having a length of 0.3 mm to 2.0 mm and a thickness of 0.5 dtex to 50 dtex is preferable. The density of the short fiber in the bristle portion is preferably set in a range between 10% and 30% which is a ratio of the fiber against a flocked area. The length of the short fiber is set to be equal to or less than the gap width of the labyrinth portion in which the short fiber is arranged. Examples of a shape of the short fiber include a straight shape and a bent shape (a shape having a bent distal end), and examples of a sectional shape include a circular shape and a polygonal shape. It is preferable to adopt the short fiber having a polygonal section because a surface area thereof is larger than that of the short fiber having a circular section.
An adhesive including a urethane resin, an epoxy resin, an acryl resin, a vinyl acetate resin, a polyimide resin or a silicon resin as a main component may be adopted. Examples of the adhesive include a urethane resin solvent-based adhesive, an epoxy resin solvent-based adhesive, a vinyl acetate resin solvent-based adhesive, an acrylic resin-based emulsion adhesive, an acrylic ester-vinyl acetate copolymer emulsion adhesive, a vinyl acetate-based emulsion adhesive, a urethane resin-based emulsion adhesive, an epoxy resin-based emulsion adhesive, a polyester-based emulsion adhesive, an ethylene-vinyl acetate copolymer-based adhesive. These adhesives may be used independently, or alternatively two or more of these adhesives may be used in combination.
As shown in
Another example of the sealing device for the bearing housing of the present invention is described with reference to
The sealing device for the bearing housing of the present invention is mainly used to fill grease into the sealing passage in addition to the inside of the bearing housing as described above (grease lubrication). A kind of grease used in the sealing device is described above. In a case in which the bearing housing is filled with the grease, an inside of a rolling bearing is filled with the grease in advance. Further, oil lubrication may be adopted in accordance with a configuration of the bearing housing. Especially in a case in which the oil lubrication is adopted in a configuration in which the bristle portion is formed, the oil is apt to be retained by the bristle portion in the labyrinth portion, and thereby excellent lubricating performance is obtained.
The sealing device for the bearing housing of the present invention can prevent or suppress entering of dust into the inner sealed space of the bearing housing and into the sealing passage such as the labyrinth portion. Therefore, the sealing device for bearing housing of the present invention can be preferably used as a sealing device in a general industrial machine, especially in an environment in which much fine dust is apt to be scattered such as in a mine, an iron mill and a power plant, or in an environment in which rainwater or cooling water pours.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2015-159696 | Aug 2015 | JP | national |
| 2015-159697 | Aug 2015 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2016/072306 | 7/29/2016 | WO | 00 |
