Rubber seal device and rolling device using rubber seal device

Abstract

To provide a rubber seal device made of a rubber material containing plant-derived biomass silica, as a filler (reinforcement agent), produced using rice husk ash as a raw material, and a rolling device using the rubber seal device.SOLUTION: A rubber seal device 9 is formed by integrally molding at least an elastic member (sealing member) 13 made of a rubber composition and a reinforcing member (sealing core) 11 that reinforces the strength of the elastic member 13, where the elastic member 13 is made of a rubber composition containing plant-derived biomass silica, as a filler (reinforcing material), produced using rice husk ash as a raw material. The rubber seal device 9 is incorporated into a rolling bearing, a linear guide device, or a ball screw.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an improvement in the rubber material of a rubber seal device that forms a rolling device. [Background technology]

[0002] Rolling devices such as rolling bearings, linear guide devices, and ball screws are equipped with rubber seal devices such as oil seals to prevent leakage of grease or lubricants and the intrusion of foreign matter from the outside. Such rubber seal devices are usually constructed by integrally joining a seal member made of a rubber material and a reinforcing member made of a metal material with an adhesive or the like. Conventionally, when wear resistance is required for the rubber material of the seal member, silica has generally been used as a filler (reinforcing agent) (see Patent Document 1).

[0003] This silica can be found in natural products, but as the shape and particle size are not uniform, synthetic silica obtained by the precipitation method, which is a wet method, is used in order to emphasize its reinforcing properties for rubber. However, wet process synthetic silica is generally synthesized by the neutralization reaction of sodium silicate and a mineral acid (usually sulfuric acid), and there is a problem that, for example, when a sealing device made of wet process synthetic silica is incinerated, carbon dioxide is released into the atmosphere, which accelerates global warming. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-275312 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made to solve such problems associated with the prior art, and its objective is to provide a rubber seal device made of a rubber material containing plant-derived biomass silica produced using rice husk ash as a filler (reinforcing agent), and a rolling device using the rubber seal device. [Means for solving the problem]

[0006] In order to achieve this object, the first invention of the present invention is a rubber seal device which is formed by integrally molding at least an elastic member made of a rubber composition and a reinforcing member which reinforces the strength of the elastic member, The rubber seal device is characterized in that the elastic member is made of a rubber composition containing biomass silica as a filler.

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

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

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

[0010] The fifth aspect of the present invention resides in that the rolling device of the second aspect of the present invention is a ball screw. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a rubber seal device made of a rubber material containing plant-derived biomass silica produced from rice husk ash as a filler (reinforcing agent), and a rolling device using the rubber seal device. This improves the bio-content of the rubber composition compared to conventional products that use synthetic silica, making it environmentally friendly and contributing to carbon neutrality. As a result, rolling devices equipped with this rubber seal device are also environmentally friendly. Furthermore, when biomass EPDM is used in rubber compositions, the bio-content of the entire rubber composition can be further improved because bio-polyethylene and bio-polypropylene are used as raw materials. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic partial cross-sectional view of a rolling bearing as an embodiment of a rolling device using a sealing device of the present invention. [Figure 2] 1 is a schematic perspective view of a linear guide device that is an embodiment of a rolling device using a seal device of the present invention. [Figure 3] 3 is an exploded perspective view showing the attachment state of each member of the slider end portion of the linear guide device shown in FIG. 2. FIG. [Figure 4] 1 is a schematic partial side view, partly cut away, showing a ball screw as an embodiment of a rolling device using a sealing device of the present invention. [Figure 5] 5 is a schematic front view showing the ball screw shown in FIG. 4 in a seventh section. FIG. [Figure 6] 5 is a schematic partial side view showing a contact portion between the thread groove of the ball screw shown in FIG. 4 and a rubber seal device. [Figure 7] 7 is a schematic enlarged view of the ball screw shown in FIG. 6, showing a state in which a rubber seal device is in contact with a screw groove. DETAILED DESCRIPTION OF THE INVENTION

[0013] An embodiment of the present invention will be described below. Note that this embodiment is merely one embodiment of the present invention and should not be construed as being limited in any way, and appropriate design modifications are possible within the scope of the present invention. First Embodiment

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

[0015] A deep groove ball bearing comprises an inner ring 1, an outer ring 3, a plurality of rolling elements (balls) 5 arranged to roll freely between the inner ring 1 and the outer ring 3, a retainer 7 that holds 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. Furthermore, biodegradable grease (not shown) is filled in the space surrounded by the inner ring 1, the outer ring 3, and the rubber seal devices 9, 9, and is sealed inside the bearing.

[0016] The rubber seal device 9 of the present invention is formed by vulcanizing and bonding a reinforcing member (seal core) 11, to which a vulcanizing adhesive has been applied in a semi-cured state, and an unvulcanized rubber composition in a mold having an internal space, by applying pressure and heating, and integrating the reinforcing member 11 and the elastic member (seal member) 13.

[0017] In order to improve adhesion, a zinc-plated steel sheet whose surface has been further subjected to a chemical conversion treatment such as zinc phosphate treatment is preferably used as the reinforcing member 11. Note that the reinforcing member 11 is not limited to the configuration of this embodiment, and can be modified in design within the scope of the present invention.

[0018] In this embodiment, for example, the seal member 13 has a plurality of annular seal lips, one of which, seal lip 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 state. The seal member 13 is not limited to the configuration of this embodiment, and can be modified in design within the scope of the present invention.

[0019] In this embodiment, a deep groove ball bearing has been described as an example of a rolling bearing, but the rubber seal device of the present invention can be applied to various other types of rolling bearings, such as radial rolling bearings such as angular contact ball bearings, cylindrical roller bearings, tapered roller bearings, needle roller bearings, and self-aligning roller bearings, and thrust rolling bearings such as thrust ball bearings and thrust roller bearings. Since the present invention is characterized by the rubber composition composition that constitutes the sealing member 13 of the rubber sealing device 9, the following will explain the rubber composition composition of the sealing member 13, and will omit explanations of the other components and effects that constitute the rolling ball bearing.

[0020] The rubber composition constituting the seal member 13 of the rubber seal device 9 of the present invention contains plant-derived biomass silica as a filler (reinforcing material). Wet process synthetic silica, which has traditionally been used to reinforce rubber, is generally synthesized by the neutralization reaction of sodium silicate and a mineral acid (usually sulfuric acid). The biomass silica used in the invention is a pioneering process that produces sodium silicate from rice husk ash using biomass energy, which reduces carbon dioxide emissions by up to 30% compared to conventional silica, making it an environmentally friendly material. In the present invention, biomass silica, which has become mass-producible, is contained as a filler (reinforcing agent) in the rubber material. A small amount of biomass carbon derived from vegetable oil may also be added for coloring purposes.

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

[0022] For special applications requiring chemical resistance to brake fluid, ethylene propylene non-conjugated diene rubber (terpolymer) is used. This ethylene propylene non-conjugated diene rubber (terpolymer) is a non-conjugated diene that can be vulcanized with ethylene, propylene, and sulfur as monomer components. The proportions of each monomer are 40 to 80% by weight of ethylene, 15 to 60% by weight of propylene, and 3 to 15% by weight of non-conjugated diene. Ethylidene norbornene (5-ethylidene-2-norbornene), dicyclopentadiene, and 1,4-hexadiene can be used as non-conjugated dienes, but ethylidene norbornene, which has high reactivity, is most preferably used.

[0023] Among the above constituent components, at least a portion of the ethylene and propylene are bioethylene and biopropylene, which are made from plant-derived bioethanol as the starting material. By using bioethylene and biopropylene as starting materials, the bio content (biomass content) of ethylene-propylene rubber is improved. Considering environmental contributions, a bio content of 20% or more is desirable, and if cost is ignored, it is possible to increase this to 85-97%. In the future, as the use of bioethanol increases and costs fall, the bio content can be increased (biomass ethanol refers to ethanol produced by fermenting and distilling biomass such as sugarcane and corn). If the bio-content is 30%, it is possible to reduce carbon dioxide emissions by approximately 40% during the manufacturing process of the raw polymer. Using biomass EPDM (ethylene propylene diene monomer) with a high bio-content increases the bio-content of the entire rubber composition, making it even more desirable. The rubber composition used in the present invention is an unvulcanized rubber obtained by mixing the above-described raw material polymer with the various compounding ingredients shown below, which is heated in a mold so as to be integrated with a core bar, and then vulcanized and bonded to form a sealing ring (annular seal).

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

[0025] [Crosslinking agent used in EPDM] (1) Sulfur (2) Peroxides (dicumyl peroxide, etc.)

[0026] [Reinforcing material used in EPDM] (1) Carbon black (biomass carbon black)

[0027] [Antioxidants used in EPDM] (1) Substituted diphenylamines (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'-Diethylthiocarbamoylthio)benzothiazole (6) 2-(4'-morpholinodithio)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 dimethyl dithiocarbamate (19) Zinc diethyl dithiocarbamate (20) Zinc di-n-butyl dithiocarbamate (21) Zinc ethylphenyl dithiocarbamate (22) Tellurium Diethyl Dithiocarbamate (23) Copper dimethyl dithiocarbamate (24) Iron dimethyl dithiocarbamate (25)Pentamethylenedithiocarbamic acid piperidine

[0028] [Vulcanization accelerators used in EPDM] (1) Complex activated zinc oxide (2) Stearic acid [Rubber softener used in EPDM] (1) Paraffin-based process oil

[0029] As described above, the rubber composition forming the seal member 13 of the rubber seal device 9 of the present invention uses biomass carbon black made from vegetable oil as a filler (reinforcing agent), which improves the bio-content of the rubber composition compared to conventional products that use carbon black derived from coal or petroleum, making it environmentally friendly and contributing to carbon neutrality. As a result, rolling devices equipped with this rubber seal device are also environmentally friendly. Furthermore, when biomass EPDM is used in rubber compositions, the bio-content of the entire rubber composition can be further improved because bio-polyethylene and bio-polypropylene are used as raw materials. Second Embodiment

[0030] 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. The linear guide device described in this embodiment is merely an example, and any device including a sealing device, which is a characteristic feature of the present invention, is not limited to other configurations. The rubber composition constituting the sealing device is the same as that described in the first embodiment, and its description will be omitted here.

[0031] In the linear guide device of this embodiment, a slider 15 having a substantially U-shaped cross section is mounted 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 of the slider body 15a. One rolling element rolling groove 17, which is a recessed groove having a cross section of a substantially quarter-circular arc, is formed in the axial direction at the ridge where the top surface 21a and both side surfaces 21b of the guide rail 21 intersect, and the other rolling element rolling groove 18, which has a cross section of a substantially semicircular arc, is formed at the intermediate position between both side surfaces 21b of the guide rail 21. is formed in the axial direction.

[0032] At the inner corners of both sleeve portions 19 of the slider body 15a, a rolling element rolling groove (not shown) having an approximately semicircular cross section is formed, which faces one of the rolling element rolling grooves 17 of the guide rail 21, and at the center of the inner surface of both sleeve portions 19, a rolling element rolling groove (not shown) having an approximately semicircular cross section is formed, which faces the other of the rolling element rolling grooves 18 of the guide rail 21. A rolling element rolling path (not shown) is formed by the rolling element rolling grooves 17, 18 of the guide rail 21 and the two rolling element rolling grooves of both sleeve portions 19. These two rolling element rolling paths are linear and have a substantially circular cross section. Furthermore, the slider 15 is provided with two rolling element return paths (not shown) consisting of through holes with a circular cross section that penetrate in the axial direction at the top and bottom of the thick-walled portion of the sleeve portion 19 of the slider body 15a.

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

[0034] The slider 15 attached to the guide rail 21 moves smoothly along the guide rail 21 via the rolling of the rolling elements in the rolling element rolling path, and during this movement, the rolling elements circulate endlessly while rolling in the circulation path within the slider 15.

[0035] The slider 15 is provided with dustproof rubber seal devices 23 attached to both axial ends (further outside the end caps 15b) to seal the opening of the gap formed between the slider 15 and the guide rail 21.

[0036] The rubber seal 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 roughly U-shaped cold-rolled steel plate or biodegradable resin that matches the outer shape of the end cap 15b through vulcanization bonding.

[0037] The seal member 25 that makes sliding contact with the guide rail 21 is formed in a shape that matches the cross-sectional shape of the guide rail 21 so that it can make sliding contact with the top surface 21a and both side surfaces 21b of the guide rail 21, so as to seal the gap between the slider 15 and the guide rail 21. However, the inner surface dimensions are slightly smaller (by about 0.3 to 0.4 mm) than the dimensions that come into contact with the surface of the guide rail 21, in order to reliably seal the gap between the guide rail 21. However, the core metal does not make contact with the guide rail 21. "Third embodiment"

[0038] 4 to 7 show an embodiment of a ball screw, which is an embodiment of a rolling device incorporating the rubber seal device of the present invention. The ball screw described in this embodiment is merely an example, and any other configuration may be used as long as it is equipped with a sealing device, which is a characteristic configuration of the present invention, and other configurations are not limited to these. The rubber composition constituting the sealing device is the same as that described in the first embodiment, and will not be described here.

[0039] The ball screw comprises a screw shaft 31 having a spiral screw groove 31a with an arc-shaped cross section on its outer surface, a cylindrical nut 33 having a spiral screw groove on its inner surface that faces the screw groove 31a of the screw shaft 31 and is screwed onto the screw shaft 31, and a large number of balls (not shown) loaded so as to roll freely in a spiral ball rolling space with an approximately circular cross section formed by the screw groove 31a of the screw shaft 31 and the screw groove of the nut 33.

[0040] Cylindrical lubricant supply members 35, 35 made of a lubricant-containing polymer are fitted inside both axial ends of the nut 33, and the inner diameter surface of the lubricant supply member 35 contacts only the outer diameter surface of the screw shaft 31 and does not contact the thread groove 31a. The lubricant supply member 35 is composed of two semi-cylindrical members and has a thin groove on its outer circumference, where a garter spring 36 is placed to press the lubricant supply member 35 radially toward the outer circumference of the screw shaft 31 with a constant pressure. Therefore, even if the inner circumference of the lubricant supply member 35 wears due to long-term operation, appropriate contact with the screw shaft 31 is always maintained, ensuring good lubrication.

[0041] Rubber seal devices 37, 37 are press-fitted onto the axially outer side of the lubricant supply member 35. The rubber seal device 37 is a sealing device composed of a core metal (reinforcing member) 37b made of cold-rolled steel plate or biodegradable resin, a disk-shaped seal member 37c containing the core metal 37b, and a seal piece 37d that is approximately conical (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 has an inner diameter that corresponds to but is slightly smaller than the cross-sectional shape of the screw shaft 31. The seal member 37c, whose outer periphery is fixed to a nut (not shown in Fig. 5), and the seal piece 37d are integrally formed from the rubber composition described in the first embodiment. The seal member 37c and the seal piece 37d are integrated with the core metal 37b by vulcanization adhesion.

[0043] The outer periphery of the core 37b is circular, but its inner periphery is similar in shape to the opening 37a, i.e., the width D2 at the bottom is smaller than the width D1 at the top, as shown in Fig. 6. Therefore, the distance D0 from the inner periphery of the core 37b to the inner periphery of the seal member 37c and the distance D3 from the inner periphery of the seal member 37c to the inner periphery of the seal piece 37d can be made constant over the entire circumference, and this makes it possible to make the amount of deflection of the rubber seal device 37 when it abuts against the screw shaft 31 almost constant.

[0044] 7 is a partially enlarged view showing the state in which the rubber seal device 37 is deformed by contact with the screw shaft 31. The rubber seal device 37 shown by the solid line is not in contact with the screw shaft 31, and the rubber seal device 37 shown by the two-dot chain line is in a state in which it is deformed by contact with the screw shaft 31. 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 fit with the outer diameter surface and the thread groove 31a of the screw shaft 31 (in reality, the gap is kept below zero by deformation).

[0045] 7, the direction in which the seal piece 37d will bend can be predicted based on its shape when the rubber seal device 37 abuts against any part of the screw shaft 31 (the outer diameter surface of the screw shaft 31 or the thread groove 31a). This makes it possible to design the shape of the seal piece 37d so as to maximize the sealing performance.

[0046] (Example of embodiment) Rolling device structure: deep groove ball bearing shown in Figure 1 Rubber seal device: It can be produced by using an unvulcanized rubber composition made of the base rubber shown in Table 1 and integrally molding it with a reinforcing member (core metal) in a mold by vulcanization bonding. [Table 1] [Industrial Applicability]

[0047] The present invention can be applied to rubber seal devices having a core metal and rolling devices using such rubber seal devices in general. [Explanation of symbols]

[0048] 1. Inner circle 3 outer ring 5 rolling elements 7 Cage 9 Rubber seal device 11 Reinforcement member 13 Elastic member (sealing member) 15 Slider 21 Guide rail 23 Rubber seal device 25 Sealing material 29 Core (reinforcing member) 31 Screw shaft 33 Nut 37 Rubber seal device 37b Core metal 37c Sealing material 37d Sticker piece

Claims

1. A rubber seal device comprising at least an elastic member made of a rubber composition and a reinforcing member for reinforcing the strength of the elastic member, which are integrally molded, A rubber seal device characterized in that the elastic member is made of a rubber composition containing biomass silica as a filler.

2. A rolling device comprising the rubber seal device according to claim 1.

3. 3. The rolling device according to claim 2, wherein the rolling device is a rolling bearing.

4. 3. The rolling device according to claim 2, wherein the rolling device is a linear guide device.

5. 3. The rolling device according to claim 2, wherein the rolling device is a ball screw.

Images