JP2002098236A - Floating seal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a floating seal with a high quality and a low price. SOLUTION: In the floating seal 1, a gap between a fixed floating seat 2 and a stationary housing 12 is sealed by a fixed seal ring 18 and a gap between a rotation floating seat 7 and a rotation housing 15 is sealed by a rotation seal ring 19. Slide surfaces 5, 10 of both floating seats 2, 7 are press-contacted with each other by a cooperation of both seal rings 18, 19 to seal a gap between both slide surfaces 5, 10. The fixed floating seat 2 and the rotation floating seat 7 are manufactured by a powder metallurgy method. Problems such as a defect, e.g. shrinkage cavity, a weight fluctuation, a maladjustment of dimension and the like are not generated at both floating seats 2, 7. Thereby, the floating seal with a high quality can be provided. Since cutting chips discharged from a machine factory, etc., can be used for a raw material, a manufacture cost can be outstandingly reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a floating seal, and more particularly to a floating seal effective as a seal for a track roller of a construction machine, a vehicle, or the like.

[0002]

2. Description of the Related Art Generally, a floating seal of this type is provided in a state of being floated on the outer peripheral side of a shaft and in a state of being opposed in an axial direction, and has a sliding surface on which the opposing surfaces can make sliding contact with each other. A fixed housing and a fixed floating seat, the fixed floating seat and the rotating floating seat, the fixed housing being provided in a state fixed to one end of the shaft, and surrounding the outer peripheral surface of the shaft with the inner peripheral surface. A fixed seal ring interposed therebetween, a rotatable housing rotatably provided at the other end of the shaft via a bearing, and surrounding the outer peripheral surface of the shaft with an inner peripheral surface; And a rotary seal ring interposed therebetween.

[0003] The sliding surfaces of both floating sheets are pressed against each other by the elastic force of both seal rings, so that the radial direction and the axial line between both housings and both floating seats can be maintained irrespective of non-rotation or rotation. It can seal from the direction and can prevent earth and sand, muddy water and the like from entering inside.

In this case, the fixed floating sheet and the rotating floating sheet are made of special cast iron, and are manufactured by a casting method such as a sand casting method, a shell molding method, and a centrifugal casting method.

[0005] However, these casting methods are inconvenient for use of a mold. Further, defects such as shrinkage cavities, blowholes, pinholes, cracks, and the like, which are peculiar to castings, may occur, and the physical properties are poor in reliability. Furthermore, weight fluctuations may occur due to fluctuations in the components of the molten metal. Furthermore, when centrifugal casting is used, dimensional inconsistencies may occur due to temperature changes in the mold. Further, a thin casting may cause warpage. Therefore, even if the casting method is relatively inexpensive in manufacturing cost, the yield is deteriorated due to the large amount of nonconforming products, and the manufacturing cost is rather increased.

The present invention solves the above-mentioned problems of the prior art, and is convenient in use of a mold, and has defects such as burrows, blowholes, pinholes and cracks. And the reliability is also high in physical properties, furthermore, there is no weight fluctuation due to the fluctuation of the components of the molten metal, and further, there is no dimensional mismatch caused by the temperature change of the mold. It is an object of the present invention to provide a floating seal which does not warp even with a thin product, has a good yield, and has a low manufacturing cost.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is provided so as to be floated on the outer peripheral side of a shaft and to be opposed in the axial direction, and to slide on the opposed surfaces. A fixed floating seat and a rotating floating seat each having a contactable sliding surface, a fixed housing fixed to the shaft, a rotating housing rotatably provided on the shaft, and the fixed floating seat and the fixed housing. A fixed seal ring interposed therebetween, and a rotary seal ring interposed between the rotary floating sheet and the rotary housing, and a sliding surface of the floating sheets by elasticity of the seal rings. In a floating seal adapted to be pressed against each other, The rolling floating sheet and the fixed floating sheet is obtained by employing the means produced by powder metallurgy. Further, at least one of the rotating floating sheet and the fixed floating sheet is formed of cast iron which is a self-lubricating composite material. By changing the molding pressure, at least one of the rotating floating sheet and the fixed floating sheet is changed to 5-1.
It employs a porous means having 0% voids. Furthermore, means in which the pores are impregnated with resin, carbon, metal or the like is employed. Further, at least one of the rotating floating sheet and the fixed floating sheet is provided with means for miniaturizing the structure and eliminating voids by interposing a powder forging step in a sintering step. . Furthermore, means is employed in which at least one of the rotating floating sheet and the fixed floating sheet is subjected to a surface treatment.

[0008]

According to the present invention, by adopting the above-mentioned means, the fixed floating sheet and the rotating floating sheet manufactured by powder metallurgy are mounted in a state of floating on the outer peripheral side of the shaft and facing in the axial direction. Will be done. The sliding force of the two floating sheets is caused by the elastic force of the fixed seal ring interposed between the fixed floating sheet and the fixed housing and the elastic force of the rotary seal ring interposed between the rotating floating sheet and the rotary housing. The moving surfaces are pressed against each other, and when the rotating housing is not rotating or rotating,
Sealing is provided between both housings and both floating seats and between both sliding surfaces of both floating seats.

[0009]

Embodiments of the present invention shown in the drawings will be described below. FIG. 1 shows an embodiment of a floating seal according to the present invention. The floating seal 1 is a fixed floating sheet provided in a state of being floated on an outer peripheral side of a shaft 20 and opposed in an axial direction. 2 and the rotating floating seat 7, a fixed housing 12 fixed to one end of the shaft 20 and surrounding the outer peripheral surface of the fixed floating seat 2 on the inner peripheral surface, and a rotating housing on the other end of the shaft 20. A rotating housing 15 which is freely provided and surrounds an outer peripheral surface of the rotating floating seat 7 on an inner peripheral surface, and a fixed seal ring 1 interposed between the fixed floating seat 2 and the fixed housing 12.
8, rotating floating seat 7 and rotating housing 1
5 and a rotary seal ring 19 interposed therebetween.

The fixed floating sheet 2 is formed in an annular shape having an inner diameter larger than the outer diameter of the shaft 20, and a groove 3 having a predetermined depth is formed on the outer peripheral surface in an annular shape over the entire circumference. It is designed to be provided. In this case, the bottom surface of the groove 3 is formed on the tapered surface 4 that gradually approaches the shaft 20 as the distance from the rotating floating sheet 7 increases.

The outer peripheral portion of the surface of the fixed floating seat 2 facing the rotating floating seat 7 is formed on an annular sliding surface 5 having a predetermined width orthogonal to the axis. The inner surface of the opposing surface that is continuous with the sliding surface 5 is formed as a tapered surface 6 that gradually moves away from the rotating floating seat 7 as it approaches the shaft 20.

The rotating floating sheet 7 is formed in an annular shape having an inner diameter larger than the outer diameter of the shaft 20, and a groove 8 having a predetermined depth is formed on the outer peripheral surface in an annular shape over the entire circumference. It is designed to be provided. In this case, the bottom surface of the groove 8 is formed on the tapered surface 9 that gradually approaches the shaft 20 as the distance from the fixed floating sheet 2 increases.

An outer peripheral portion of the surface of the rotating floating sheet 7 facing the fixed floating sheet 2 is formed on an annular sliding surface 10 having a predetermined width orthogonal to the axis. The inner surface of the opposing surface that is continuous with the sliding surface 10 is formed as a tapered surface 11 that gradually moves away from the fixed floating seat 2 as it approaches the shaft 20.

The fixed housing 12 is fixed to one end of the shaft 20 and has an inner peripheral surface surrounding the outer peripheral surface of the fixed floating sheet 2. On the inner peripheral surface surrounding the outer peripheral surface of the fixed floating sheet 2 of the fixed housing 12, a groove 13 having a predetermined depth is provided over the entire periphery.
In this case, the bottom surface of the groove 13 is formed as a tapered surface 14 inclined in the same direction as the bottom surface of the groove 3 on the outer peripheral surface of the fixed floating sheet 2.

The rotary housing 15 is rotatably provided at the other end of the shaft 20 via a bearing (not shown), and has an inner peripheral surface surrounding the outer peripheral surface of the rotary floating sheet 7. Has become. Rotating housing 1
A groove 16 having a predetermined depth is provided on the inner peripheral surface surrounding the outer peripheral surface of the rotary floating sheet 7 of No. 5 over the entire circumference. In this case, the bottom surface of the groove 16 is formed as a tapered surface 17 inclined in the same direction as the bottom surface of the groove 8 on the outer peripheral surface of the rotating floating sheet 7.

A fixed seal ring 18 is interposed between the groove 3 on the outer peripheral surface of the fixed floating sheet 2 and the groove 13 on the inner peripheral surface of the fixed housing 12. The fixed seal ring 18 is formed in an annular shape formed of an elastic body such as rubber, and the elastic force of the fixed seal ring 18 causes the space between the fixed housing 12 and the fixed floating sheet 2 from the radial direction and the axial direction. It is designed to be sealed. Further, the fixed floating sheet 2 is pressed in the direction of the rotating floating sheet 7 by the elastic force of the fixed seal ring 18, whereby the sliding surface 5 of the fixed floating sheet 2 is pressed against the sliding surface 10 of the rotating floating sheet 7. And both sliding surfaces 5, 10
The space is sealed when the rotating housing 15 is not rotating or rotating.

A rotary seal ring 19 is interposed between the groove 8 on the outer peripheral surface of the rotary floating seat 7 and the groove 16 on the inner peripheral surface of the rotary housing 15. The rotary seal ring 19 is formed in an annular shape formed of an elastic body such as rubber, and the elastic force of the rotary seal ring 19 allows the space between the rotary housing 15 and the rotary floating sheet 7 to be changed from the radial direction and the axial direction. It is designed to be sealed. Also, the rotating floating sheet 7 is pressed in the direction of the fixed floating sheet 2 by the elastic force of the rotating seal ring 19, whereby the sliding surface 10 of the rotating floating sheet 7 is pressed against the sliding surface 5 of the fixed floating sheet 2. And both sliding surfaces 10, 5
The space is sealed when the rotating housing 15 is not rotating or rotating.

The fixed floating seat 2 of the floating seal 1 according to this embodiment having the above-described configuration.
The rotating floating sheet 7 is manufactured by a powder metallurgy method. In other words, four steps of “raw material powder manufacturing process”, “powder blending and mixing process”, “compacting process”, and “sintering process”
And a post-processing step, followed by five steps.

In the "production process of raw material powder", the raw material powder is obtained by "method of mechanically pulverizing raw materials in a solid state", "method of pulverizing molten metal by gas spraying, water spraying, centrifugal spraying, roll spraying" , "Chemical methods such as reduction, thermal decomposition, and wet electrolysis" and the like.

For example, when the raw material powder is cast iron, it is manufactured by a “mechanical grinding method”. That is, a raw material powder having a predetermined particle size can be produced by cutting an ingot-like raw material into a chip shape by cutting and mechanically pulverizing it. In this case, a cutting powder (cutting powder) discharged from a machine factory or the like may be used as a raw material, and the raw material powder having a predetermined particle size may be manufactured by mechanically pulverizing the same. In that case, raw material costs and processing costs can be reduced.

In the "powder blending / mixing step", the raw material powders are mixed for a predetermined time by using a mixer such as a ball mill, a rod mill, and a blender. In this case, a binder, an alloy component, a lubricant and the like are added to the raw material powder according to the purpose.

In the "compacting step", a cavity is filled with raw material powder using a mold, and compression molding is carried out using a press machine to form a compact conforming to the shape of the cavity. In this case, by adjusting the molding pressure, the amount of holes formed in the molded body can be adjusted. For example, it can be formed to be porous having 5 to 10% of pores.

In the "sintering step", the compact formed in the powder compacting step is loaded into a sintering furnace and heated at a predetermined temperature for a predetermined time to diffuse atoms of each powder. Metallurgy. In this case, as the protective atmosphere, a reducing gas such as an inert gas such as vacuum and argon, hydrogen, cracked ammonia gas, and modified hydrocarbon gas is used. When the raw material powder is cast iron, since a large amount of silicon is contained in addition to carbon, it is necessary to take care that the protective atmosphere does not become an oxidizing atmosphere.

In the "post-treatment step", depending on the purpose, a lubricant, a resin, carbon, a metal, or the like is impregnated.
Copper, copper alloy, etc. are infiltrated, heat treatment such as quenching, tempering, carburizing and quenching, carbonitriding, sizing, and forging are performed. When sizing and forging are performed, the structure can be refined, and a product having no pores can be manufactured.

In the floating seal 1 according to this embodiment configured as described above, since the fixed floating sheet 2 and the rotating floating sheet 7 are manufactured by powder metallurgy, casting using a conventional mold is performed. Unlike the law, the usability of the mold is greatly improved.

Since the fixed floating sheet 2 and the rotating floating sheet 7 have characteristics as a sintered body, defects such as shrinkage cavities, blowholes, pinholes, cracks, etc. are generated as in a casting. That is, it is possible to provide a highly reliable product in terms of physical properties.

Furthermore, in the powder metallurgy method, the raw material powder is compression-molded, and thermal energy is applied to the raw material powder to diffuse the atoms of the respective particles to form a metallic bond. In addition, the weight fluctuation due to the fluctuation of the components of the molten metal does not occur.

Further, there is no dimensional mismatch caused by a change in the mold temperature.

Further, a product having a small diameter can be manufactured, and warping does not occur even in a thin product.

Further, in addition to cast iron having self-lubricating properties, various materials such as copper alloys and stainless steels can be used as raw materials according to the purpose. Can be done.

Further, in the post-processing, the wear resistance of the sliding surface is increased by impregnating a resin, carbon, metal, or the like, the lubricating property of the sliding surface is increased by impregnating with a lubricant, copper, Improve mechanical properties by infiltrating copper alloys, etc., improve dimensional accuracy by sizing, or densify by hot forging residual holes in sintered body to increase strength. Can be provided, so that it is possible to provide one according to the purpose.

An embodiment of the floating seal 1 according to the present invention will be described below. <Example 1> As raw material powder, 85% of cast iron powder having an average particle diameter of 180 µm and 1
5%. Then, 4.0 parts by weight of electrolytic copper powder and 0.7 parts by weight of natural graphite powder were mixed with 100 parts by weight of cast iron powder. Further, 0.7 parts by weight of zinc stearate was added as a binder, and mixed by a mixer. This is filled into the cavity of the mold, and is pressed by a press machine.
Pressure molding was performed at 0 MPa. The obtained compact was placed in a sintering furnace and sintered at 1150 ° C. for 2 hours in an argon atmosphere. Further, the sintered body was re-compressed at 600 MPa in order to reduce the number of pores and increase the density. This made the structure finer and more uniform. In casting, the problem of inevitable casting cavities has been solved. When the strength of the sintered body was measured, 6 MPa was obtained even though the main component was gray cast iron (see FIG. 2). <Example 2> The molded body of Example 1 was placed in an argon atmosphere.
It was sintered at a temperature of 1150 ° C. for 2 hours. 900 ° C
For carburizing heat treatment. The tissue obtained a situation in which spheroidized graphite was scattered. Similarly, when the tensile strength was measured,
It was 10 MPa (see FIG. 3).

[0033]

According to the present invention, since the rotating floating sheet and the fixed floating sheet are manufactured by the powder metallurgy method, the usability of the mold can be greatly improved. become. In addition, since it has the characteristics as a sintered body, it does not cause defects such as shrinkage cavities, blow holes, pin holes, cracks, etc. unlike castings, and can improve physical reliability. become. Further, since the raw material powder is used, the weight does not fluctuate due to the fluctuation of the components of the molten metal. Further, since a mold is used, dimensional mismatch due to temperature change of the mold does not occur. Furthermore, since a mold is used, even if the product has a small diameter, a product having a complicated shape, a thin product, or the like, a problem such as warpage does not occur. Further, by adjusting the molding pressure, the amount of pores in the sintered body can be adjusted, so that a material having characteristics suitable for the purpose can be obtained. Furthermore, in addition to cast iron having self-lubricating properties, various materials such as copper alloys and stainless steels can be used as raw materials, so that corrosion resistance and the like can be improved by using raw materials according to the purpose. become. Furthermore, in the post-treatment, the wear resistance of the sliding surface is increased by impregnating the resin, carbon, metal, or the like, or the lubrication of the sliding surface is increased by impregnating the lubricant,
Improve mechanical properties by infiltrating copper, copper alloy, etc., improve dimensional accuracy by sizing, or densify by forging hot holes remaining in the sintered body to increase strength. Since it can be increased, it is possible to obtain a material having characteristics according to the purpose.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a floating seal according to the present invention.

FIG. 2 is an explanatory view showing an example of a method for sintering a floating seal according to the present invention.

FIG. 3 is an explanatory view showing another example of a method for sintering a floating seal according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Floating seal 2 ... Fixed floating sheet 3, 8, 13, 16 ... Groove 4, 6, 9, 11, 14, 17 ... Tapered surface 5, 10 ... Sliding surface 7 ... Rotating floating sheet 12 ... fixed housing 15 ... rotating housing 18 ... fixed sealing ring 19 ... rotating sealing ring 20 ... shaft

Claims (6)

[Claims] 1. A fixed floating sheet and a rotating floating sheet which are provided in a state of being floated on an outer peripheral side of a shaft and opposed to each other in an axial direction, and each having a sliding surface capable of slidingly contacting with an opposed surface, A fixed housing fixed to the shaft, a rotatable housing rotatably provided on the shaft, a fixed seal ring interposed between the fixed floating seat and the fixed housing; A rotary seal ring interposed between the rotary floating sheet and the housing, wherein the sliding surfaces of the floating sheets are pressed against each other by the elastic force of the seal rings. And the fixed floating seat Floating seal being characterized in that produced by powder metallurgy. 2. The method according to claim 1, wherein at least one of the rotating floating sheet and the fixed floating sheet is
The floating seal according to claim 1, wherein the floating seal is formed from a cast iron that is a self-lubricating composite material. 3. The method according to claim 1, wherein at least one of the rotating floating sheet and the fixed floating sheet is
3. The floating seal according to claim 1, wherein the floating seal is formed to have a pore of 5 to 10% by changing a molding pressure. 4. The floating seal according to claim 3, wherein said holes are impregnated with resin, carbon, metal or the like. 5. At least one of the rotating floating sheet and the fixed floating sheet,
The floating seal according to claim 1 or 2, wherein the powder forging step is interposed between the sintering step and the structure is refined and voids are eliminated. 6. The floating seal according to claim 1, wherein a surface treatment is applied to at least one of the rotating floating sheet and the fixed floating sheet.