Rubber seal device and rolling device using rubber seal device

Abstract

To provide a rubber seal device that is environmentally friendly and uses a rubber composition using a plant-origin biomass carbon manufactured using vegetable oil as a raw material, as a filler material (a reinforcement agent), and to provide a rolling device using the rubber seal device.SOLUTION: A rubber seal device 9 is formed by integrally molding at least an elastic member 13 made of a rubber composition and a reinforcement member 11 reinforcing strength of the elastic member 13. The elastic member 13 comprises a rubber composition containing biomass carbon black as a filler material. The rubber seal device 9 is disposed in a rolling device.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an improvement in a rubber material of a rubber sealing device forming a rolling device.

Background Art

[0002] In rolling devices such as rolling bearings, linear guide devices, and ball screws, a rubber sealing device such as an oil seal is attached to prevent leakage of grease or lubricant and intrusion of foreign matter from the outside. Such a rubber sealing device is usually configured by integrally joining a seal member made of a rubber composition and a reinforcing member made of metal with an adhesive or the like. Conventionally, carbon black has been generally used as a filler (reinforcing agent) in the rubber composition (see Patent Document 1).

[0003] However, this carbon black is made from coal-based and petroleum-based heavy oils rich in aromatic components and is not environmentally friendly. For example, various environmental problems occur in the disposal of a sealing device made of carbon black made from coal-based and petroleum-based heavy oils. That is, when a sealing device made of carbon black made from coal-based and petroleum-based heavy oils is incinerated or the like, carbon dioxide is released into the atmosphere, promoting global warming. In addition, sulfur oxides and nitrogen oxides are generated, and there is also a risk that air pollution caused by these will have an adverse effect on the human body. Furthermore, coal-based and petroleum-based heavy oils are finite and depleting resources, and globally, there is a global effort to reduce dependence on depleting resources. The adoption of SDGs (Sustainable Development Goals) is one of them, and the goal is to phase out from depleting resources (fossil fuels).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0005] The present invention has been made to solve such problems of the prior art, and an object thereof is to provide an environmentally friendly rubber sealing device using a rubber composition filled with plant-derived biomass carbon produced from vegetable oil as a filler (reinforcing agent), and a rolling device using this rubber sealing device.

MEANS FOR SOLVING THE PROBLEMS

[0006] To achieve this object, a first aspect of the present invention is a rubber sealing device in which at least an elastic member made of a rubber composition and a reinforcing member for reinforcing the strength of the elastic member are integrally formed, wherein the elastic member is made of a rubber composition containing biomass carbon black as a filler.

[0007] A second aspect of the present invention is a rolling device in which the rubber sealing device of the first aspect is disposed.

[0008] A third aspect of the present invention is that the rolling device of the second aspect is used as a rolling bearing.

[0009] A fourth aspect of the present invention is that the rolling device of the second aspect is used as a linear guide device.

[0010] A fifth aspect of the present invention is that the rolling device of the second aspect is used as a ball screw.

EFFECTS OF THE INVENTION

[0011] According to the present invention, it is possible to provide a rubber sealing device and a rolling device using the rubber sealing device, which are made of a rubber material filled with plant-derived biomass carbon produced from vegetable oil as a filler (reinforcing agent). As a result, compared with conventional products using carbon black derived from coal and petroleum, the bio-degree of the rubber composition is improved, it is environmentally friendly, and it contributes to carbon neutrality. Thereby, the rolling device provided with this rubber sealing device also becomes environmentally friendly. In addition, when biomass EPDM is applied to the rubber composition, since biopolyethylene and biopolypropylene are used as raw materials, the bio-degree of the entire rubber composition can be further improved. Furthermore, according to the present invention, it is possible to eliminate the environmental problems of the rubber sealing device using depleted resources by moving away from depleted resources.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0013] Hereinafter, an embodiment of the present invention will be described. It should be noted that this embodiment is merely one embodiment of the present invention and should not be construed as being limited in any way, and design changes can be made as appropriate within the scope of the present invention. "First Embodiment"

[0014] In this embodiment, as an embodiment of a rolling device, for example, a deep groove ball bearing shown in FIG. 1 is shown.

[0015] The deep groove ball bearing includes an inner ring 1, an outer ring 3, a plurality of rolling elements (balls) 5 rotatably disposed between the inner ring 1 and the outer ring 3, a cage 7 for holding the rolling elements 5 between the inner ring 1 and the outer ring 3, and an annular rubber seal device 9 attached to the seal groove 3a of the outer ring 3 and interposed between the inner ring 1 and the outer ring 3. In addition, a biodegradable grease (not shown) filled in the space surrounded by the inner ring 1, the outer ring 3, and the rubber seal devices 9, 9 is sealed inside the bearing.

[0016] The rubber seal device 9 forming the present invention is formed by vulcanizing and adhering a reinforcing member (seal core metal) 11 coated with a vulcanizing adhesive in a semi-cured state in a mold having an internal space and an unvulcanized rubber composition by heating while applying pressure, and the reinforcing member 11 and the elastic member (seal member) 13 are integrated.

[0017] In order to improve adhesiveness, the reinforcing member 11 is preferably a zinc-plated steel sheet surface further subjected to a chemical conversion treatment such as zinc phosphate. It should be noted that the reinforcing member 11 is not construed as being limited to the configuration of this embodiment and can be designed and changed within the scope of the present invention.

[0018] In this embodiment, for example, the seal member 13 includes a plurality of annular seal lips, and one of the seal lips 13a contacts the annular wall 1b of the seal groove 1a of the inner ring 1, and the other seal lips 13b, 13c are provided in a non-contact form. It should be noted that the seal member 13 is not construed as being limited to the configuration of this embodiment and can be designed and changed within the scope of the present invention.

[0019] In this embodiment, a deep groove ball bearing is exemplified and described as the rolling bearing. However, the rubber sealing device of the present invention can be applied to various other types of rolling bearings. For example, radial rolling bearings such as angular ball bearings, cylindrical roller bearings, tapered roller bearings, needle roller bearings, self-aligning roller bearings, etc., and thrust rolling bearings such as thrust ball bearings, thrust roller bearings, etc. Since the present invention is characterized by the composition of the rubber composition constituting the seal member 13 of the rubber sealing device 9, the composition of the rubber composition of the seal member 13 will be described below, and the description of other components and functions and effects constituting the rolling ball bearing will be omitted.

[0020] The rubber composition constituting the seal member 13 of the rubber sealing device 9 of the present invention contains plant-derived biomass carbon black as a filler. Conventional carbon black is mass-produced by controlling various properties by using coal-based and petroleum-based heavy oils rich in aromatic components as raw materials and incompletely burning these raw materials. When this raw material is replaced with vegetable oils such as castor oil and pine oil, it could not be mass-produced because of the low content of aromatic components. However, by devising the manufacturing technology, mass production of biomass carbon black from vegetable oil raw materials has become possible. Therefore, in the present invention, biomass carbon black that can be mass-produced is contained as a filler (reinforcing agent) for the rubber material.

[0021] The base rubber of the rubber composition forming the seal member 13 of the rubber sealing device 9 is selected from acrylonitrile-butadiene rubber, hydrogenated acrylonitrile-butadiene rubber, acrylic rubber, fluororubber, silicone rubber, etc. according to the heat resistance and oil resistance required for the rolling device.

[0022] In applications where chemical resistance to brake fluid is required for special uses, ethylene propylene non-conjugated diene rubber (ternary copolymer) is used. This ethylene-propylene non-conjugated diene rubber (ternary copolymer) has, as the constituent components of the monomers, ethylene, propylene, and a non-conjugated diene capable of vulcanization with sulfur. The proportion of each monomer is 40 to 80% by weight of ethylene, 15 to 60% of propylene, and 3 to 15% by weight of the non-conjugated diene. As the non-conjugated diene, ethylidene norbornene (5-ethylidene-2-norbornene), dicyclopentadiene, and 1,4-hexadiene can be used, but ethylidene norbornene with high reactivity is most preferably used.

[0023] Among the above constituent components, at least a part of ethylene and propylene is bio-ethylene and bio-propylene starting from plant-derived bio-ethanol. By using bio-ethylene and bio-propylene as starting materials, the bio-degree (biomass degree) of the ethylene-propylene rubber is improved. Considering the contribution to the environment, the bio-degree is preferably 20% or more, and if cost is disregarded, it can be improved up to 85 to 97%. In the future, as the use of bio-ethanol increases and cost reduction progresses, the bio-degree can be increased. If the bio-degree is assumed to be 30%, it is possible to reduce about 40% of carbon dioxide in the manufacturing process of the raw material polymer. Using this high bio-degree biomass EPDM (ethylene propylene diene monomer) is more preferable as it improves the bio-degree of the entire rubber composition. The rubber composition used in the present invention is an unvulcanized rubber in which various compounding agents shown below are mixed with the above-described raw material polymer, heated in a mold so as to be integrated with the core metal, and vulcanization-bonded to form a seal ring (annular seal).

[0024] Taking EPDM as an example, various compounding agents are shown below.

[0025] [Crosslinking agents used for EPDM] (1) Sulfur (2) Peroxides (such as dicumyl peroxide, etc.)

[0026] [Reinforcing Materials Used in EPDM] (1) Carbon Black (Biomass Carbon Black)

[0027] [Antioxidants Used in EPDM] (1) Substituted Diphenylamine (2) N,N’-Diphenyl-p-phenylenediamine (3) Polymer of 2,2,4-Trimethyl-1,2-dihydroquinoline (4) 4,4’-Methylene-bis-(2,6-di-tert-butylphenol) [Vulcanization Accelerators Used in EPDM] (1) 2-Mercaptobenzothiazole (2) Dibenzothiazyl Disulfide (3) Zinc Salt of 2-Mercaptobenzothiazole (4) Cyclohexylamine Salt of 2-Mercaptobenzothiazole (5) 2-(N,N’-Diethylthio-carbamoylthio)benzothiazole (6) 2-(4’-Morpholino-dithio)benzothiazole (7) N-Cyclohexyl-2-benzothiazyl Sulfenamide (8) N,N-Dicyclohexyl-2-benzothiazyl Sulfenamide (9) N-Oxydiethylene-2-benzothiazyl Sulfenamide (10) N-tert-Butyl-2-benzothiazyl Sulfenamide (11) Diethyl Thiourea (12) Dibutyl Thiourea (13) Tetramethylthiuram Monosulfide (14) Tetramethylthiuram Disulfide (15) Tetraethylthiuram Disulfide (16) Dipentamethylenethiuram Tetra or Hexasulfide (17) Tetrakis(2-ethylhexyl)thiuram Disulfide (18) Zinc Dimethyldithiocarbamate (19) Zinc diethyldithiocarbamate (20) Zinc di-n-butyldithiocarbamate (21) Zinc ethylphenyldithiocarbamate (22) Tellurium diethyldithiocarbamate (23) Copper dimethyldithiocarbamate (24) Iron dimethyldithiocarbamate (25) Piperidine pentamethylenedithiocarbamate

[0028] [Vulcanization accelerator aids used in EPDM] (1) Composite active zinc white (2) Stearic acid [Rubber softeners used in EPDM] (1) Paraffinic process oil

[0029] As described above, in the rubber composition forming the seal member 13 of the rubber seal device 9 of the present invention, by using biomass carbon black made from vegetable oil as a filler (reinforcing agent), compared with conventional products using carbon black derived from coal and petroleum, the bio-degree of the rubber composition is improved, it is environmentally friendly, and it contributes to carbon neutrality. As a result, the rolling device equipped with this rubber seal device is also environmentally friendly. In addition, when biomass EPDM is applied to the rubber composition, since biopolyethylene and biopolypropylene are used as raw materials, the bio-degree of the entire rubber composition can be further improved. Furthermore, by using biomass carbon black made from vegetable oil as a filler for the rubber composition forming the seal member 13, it is possible to eliminate the use of depleted resources and solve the environmental problems of rubber seal devices using depleted resources. "Second Embodiment"

[0030] Figs. 2 and 3 show an embodiment of a linear guide device which is an embodiment of a rolling device incorporating the rubber seal device of the present invention. Note that the linear guide device described in this embodiment is an example, and it suffices as long as it includes the seal device which is a characteristic configuration of the present invention, and the other configurations are not limitedly construed. Also, regarding the rubber composition constituting the seal device, the description in the first embodiment is incorporated herein and the description here is omitted.

[0031] In the linear guide device of this embodiment, a slider 15 having a substantially U-shaped cross-sectional shape is straddled on a rectangular guide rail 21 so as to be relatively movable in the axial direction. The slider 15 is composed of a slider body 15a and end caps 15b detachably attached to both axial ends thereof. On the ridge line portion where the upper surface 21a and both side surfaces 21b of the guide rail 21 intersect, one rolling element rolling groove 17 formed of a concave groove having a substantially quarter-circular cross section is formed in the axial direction, and at an intermediate position between both side surfaces 21b of the guide rail 21, the other rolling element rolling groove 18 is formed in the axial direction.

[0032] At the inner corner portions of both sleeve portions 19 of the slider body 15a, rolling element rolling grooves (not shown) having a substantially semi-circular cross section facing one rolling element rolling groove 17 of the guide rail 21 are formed, and at the central portions of the inner surfaces of both sleeve portions 19, rolling element rolling grooves (not shown) having a substantially semi-circular cross section facing the other rolling element rolling groove 18 of the guide rail 21 are formed. With the rolling element rolling grooves 17 and 18 of the guide rail 21 and the two rolling element rolling grooves of both sleeve portions 19, rolling element rolling paths (not shown) are formed. These two rolling element rolling paths are substantially circular in cross section and linear. Further, the slider 15 is provided with two rolling element return paths (not shown) each formed of a through hole having a circular cross section penetrating in the axial direction at the upper and lower portions of the thick portion of the sleeve portion 19 of the slider body 15a.

[0033] The end cap 15b has a curved path (not shown) that communicates the rolling element rolling path and the rolling element return path parallel thereto. The rolling element rolling path, the rolling element return path, and the curved paths at both ends form a circulation path for the rolling elements. A large number of rolling elements (not shown), such as steel balls, are freely loaded and rolling in this circulation path of the rolling elements.

[0034] The slider 15 assembled to the guide rail 21 smoothly moves along the guide rail 21 through the rolling of the rolling elements in the rolling element rolling path. During the movement, the rolling elements infinitely circulate while rolling in the circulation path in the slider 15.

[0035] A rubber sealing device 23 for dust prevention that seals the opening of the gap formed between the slider 15 and the guide rail 21 is attached to both axial ends (further outside the end cap 15b).

[0036] The rubber sealing device 23 is a sealing device formed by integrating a seal member 25 made of the rubber composition described in the first embodiment and a core metal (reinforcing member) 29 made of a substantially U-shaped cold-rolled steel sheet or biodegradable resin that conforms to the outer shape of the end cap 15b by vulcanization adhesion.

[0037] The seal member 25 that slidably contacts the guide rail 21 is formed into a shape that can slidably contact the upper surface 21a and both side surfaces 21b of the guide rail 21 according to the cross-sectional shape of the guide rail 21 so as to seal the gap between the slider 15 and the guide rail 21. However, the inner dimension thereof is made slightly (about 0.3 to 0.4 mm) smaller than the dimension that contacts the surface of the guide rail 21 in order to surely seal the gap with the guide rail 21. However, the core metal is not in contact with the guide rail 21. "Third Embodiment"

[0038] FIGS. 4 to 7 show an embodiment of a ball screw, which is an embodiment of a rolling device incorporating the rubber sealing device of the present invention. Note that the ball screw described in this embodiment is merely an example, and any device may be used as long as it includes the sealing device which is a characteristic configuration of the present invention. The other configurations are not limitedly interpreted. Also, regarding the rubber composition constituting the sealing device, the description in the first embodiment is incorporated herein and the description here is omitted.

[0039] The ball screw includes a screw shaft 31 having a helical thread groove 31a with an arcuate cross-section on its outer peripheral surface, a cylindrical nut 33 having a helical thread groove on its inner surface facing the thread groove 31a of the screw shaft 31 and being screwed onto the screw shaft 31, and a number of balls (not shown) that are rotatably loaded into a substantially circular helical ball rolling space formed by the thread groove 31a of the screw shaft 31 and the thread groove of the nut 33.

[0040] Inside both axial ends of the nut 33, cylindrical lubricant supply members 35, 35 made of a lubricant-containing polymer are inserted. The inner diameter surface of the lubricant supply member 35 contacts only the outer diameter surface of the screw shaft 31 and is not in contact with the thread groove 31a. The lubricant supply member 35 is composed of two semi-cylindrical members and has a thin groove on its outer peripheral surface. By a garter spring 36 disposed here, the lubricant supply member 35 is radially pressed toward the outer periphery of the screw shaft 31 with a certain pressure. Therefore, even if the inner peripheral surface of the lubricant supply member 35 is worn due to long-term operation, appropriate contact with the screw shaft 31 is always maintained, ensuring good lubrication.

[0041] Outside the axial direction of the lubricant supply member 35, rubber seal devices 37, 37 are press-fitted. The rubber seal device 37 is a sealing device composed of a core metal (reinforcing member) 37b made of cold-rolled steel sheet or biodegradable resin, a disc-shaped seal member 37c enclosing the core metal 37b, and a seal piece 37d having a substantially conical shape (inclined to the left in each figure) extending inward from the seal member 37c.

[0042] The seal piece 37d has an opening 37a at its center that corresponds to and is slightly smaller in inner diameter than the cross-sectional shape of the screw shaft 31. In FIG. 5, the seal member 37c that fixes its outer periphery to a nut (not shown) and the seal piece 37d are integrally formed of the rubber composition described in the first embodiment. The seal member 37c and the seal piece 37d and the core metal 37b are integrated by vulcanization adhesion.

[0043] The outer periphery of the core metal 37b is circular, but its inner periphery is similar to the opening 37a, that is, as shown in FIG. 6, the width D2 at the lower part is smaller than the width D1 at the upper part. Therefore, the distance D0 from the inner peripheral edge of the core metal 37b to the inner peripheral edge of the seal member 37c and the distance D3 from the inner peripheral edge of the seal member 37c to the inner peripheral edge of the seal piece 37d can be made constant over the entire circumference. As a result, the amount of deflection of the rubber seal device 37 when contacting the screw shaft 31 can be made substantially constant.

[0044] FIG. 7 is a partially enlarged view showing the state in which the rubber seal device 37 is in contact with the screw shaft 31 and deformed. The rubber seal device 37 shown by the solid line is in a state of not contacting the screw shaft 31, and the rubber seal device 37 shown by the two-dot chain line is in a state of contacting the screw shaft 31 and being deformed. The contact portion (lip portion) of the seal piece 37d of the rubber seal device 37 with the screw shaft 31 always has an interference with respect to the outer diameter surface and the screw groove 31a of the screw shaft 31 (actually, the gap is kept at 0 or less due to deformation).

[0045] As can be seen from FIG. 7, even when the rubber seal device 37 contacts any part of the screw shaft 31 (the outer diameter surface or the screw groove 31a of the screw shaft 31), the deflection direction of the seal piece 37d can be predicted based on its shape. Therefore, it is possible to design the shape of the seal piece 37d so that the sealing performance becomes the highest.

[0046] (Example of the embodiment) Structure of the rolling device: The deep groove ball bearing shown in FIG. 1 Rubber sealing device: It is manufactured by integrally molding in a mold with a reinforcing member (core metal) by vulcanization adhesion using an unvulcanized product of a rubber composition made of the base rubber shown in Table 1.

Table 1

Industrial Applicability

[0047] The present invention can be used for a rubber sealing device having a core metal and generally for a rolling device using the rubber sealing device.

Explanation of Reference Numerals

[0048] 1 Inner ring 3 Outer ring 5 Rolling element 7 Cage 9 Rubber sealing device 11 Reinforcing member 13 Elastic member (sealing member) 15 Slider 21 Guide rail 23 Rubber sealing device 25 Sealing member 29 Core metal (reinforcing member) 31 Screw shaft 33 Nut 37 Rubber sealing device 37b Core metal 37c Sealing member 37d Sealing piece

Claims

1. A rubber seal device in which at least an elastic member made of a rubber composition and a reinforcing member for reinforcing the strength of the elastic member are integrally formed, wherein the elastic member is made of a rubber composition containing biomass carbon black as a filler. The rubber seal device is characterized by this.

2. A rolling device characterized in that the rubber seal device according to Claim 1 is provided.

3. The rolling device according to Claim 2, characterized in that it is a rolling bearing.

4. The rolling device according to Claim 2, characterized in that it is a linear guide device.

5. The rolling device according to Claim 2, characterized in that it is a ball screw.

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