gasket

Abstract

To provide a gasket that has excellent vibration control property and vibration-proof property.SOLUTION: A gasket includes an elastic part including a nitrile rubber containing 31-35% nitrile, where a dynamic spring constant measured under a condition of 23±2°C, 100 Hz and a distortion amplitude of 0.1% according to JIS K6394: 2007 is 1.5 g / μm or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a gasket. [Background technology]

[0002] Currently, gaskets made of laminated rubber and metal are used in various fields, including automobiles. Gaskets are required to have high sealing properties, and therefore, efforts are being made to improve their compression set resistance (CS), stress relaxation properties, and rubber hardness. Patent Document 1 (WO 2011 / 024812) discloses a metal gasket made of multiple laminated metal sheets and sealing materials made of elastomers (Claim 1, paragraph

[0044] ).

[0003] In recent years, automobiles have become increasingly hybrid and electric, and environmentally friendly vehicles such as fuel cell vehicles are being developed. These vehicles use gaskets for motors, gaskets for batteries such as secondary batteries and fuel cells, and gaskets for power control units. Environmentally friendly vehicles such as hybrid vehicles, electric vehicles, and fuel cell vehicles use motors, which generate vibrations when the motors are in operation. Therefore, there has been a demand for suppressing the vibrations generated in these environmentally friendly vehicles. There has also been a demand for suppressing vibrations originating from sources such as motors in equipment other than environmentally friendly vehicles. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2011 / 024812 Summary of the Invention [Problem to be solved by the invention]

[0005] Although the gasket of Patent Document 1 has high sealing properties, further improvement in vibration damping and vibration isolation functions is desired. The present invention has been made in view of the above circumstances, and provides a gasket with excellent vibration damping and vibration isolation properties. [Means for solving the problem]

[0006] The embodiments of the present invention are as follows. [1] A gasket having an elastic part containing rubber having a dynamic spring constant of 1.5 g / μm or less measured under the conditions of 23±2°C, 100 Hz, and strain amplitude of 0.1% as specified in JIS K6394:2007. [2] The gasket according to [1] above, wherein the hardness of the rubber is 90 or less. [3] A metal plate; The elastic portion is provided on one or both sides of the metal plate. The gasket according to [1] or [2] above, [4] A gasket according to any one of [1] to [3] above, wherein the rubber is nitrile rubber. [5] The gasket according to any one of [1] to [4] above, which is a gasket for a motor. [6] The gasket according to any one of [1] to [4] above, which is a gasket for an inverter case. [Effects of the Invention]

[0007] A gasket having excellent vibration damping and vibration isolation properties can be provided. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is an exploded perspective view of a housing to which an example of a gasket according to an embodiment of the present invention is applied. DETAILED DESCRIPTION OF THE INVENTION

[0009] The gasket of the present invention has an elastic portion containing rubber having a dynamic spring constant of 1.5 g / μm or less, as measured under the conditions of 23±2°C, 100 Hz, and a strain amplitude of 0.1%, as specified in JIS K6394:2007. A rubber dynamic spring constant of 1.5 g / μm or less reduces the transmission of vibration from a vibration source to the gasket. Furthermore, even if vibration is transmitted from the vibration source into the elastic portion, the vibration is easily converted into thermal energy within the elastic portion. As a result, the gasket has excellent vibration-damping and vibration-proofing properties and can effectively prevent vibration from being transmitted from the vibration source to other components. Furthermore, because the gasket suppresses vibration from the vibration source, it can reduce noise caused by the vibration and improve the quietness of equipment incorporating the gasket. Typically, the elastic portion is made of rubber having a dynamic spring constant of 1.5 g / μm or less. For example, the gasket can be used in motors and inverter cases, reducing the vibration and noise generated by these devices. The gasket can also be used inside machinery and equipment such as automobiles, robots, and home appliances that are equipped with motors or inverter cases. When the gasket of the present invention is used in an automobile, vibration and noise are reduced, allowing the automobile to be driven in a comfortable environment.

[0010] The dynamic spring constant of the rubber constituting the elastic portion is measured as follows. The vulcanization rate of the rubber composition for the elastic portion is measured in advance in accordance with JIS K6300-2. c (90) (90% vulcanization time) is measured. cA rubber piece is prepared by pressurizing and vulcanizing the rubber composition for the elastic portion under conditions exceeding (90). Then, in accordance with the forced vibration non-resonance method described in JIS K6394:2007, the dynamic spring constant is measured by a tensile method under conditions of 23±2°C, 100 Hz, and a strain amplitude of 0.1%. A Rheogel-E4000 manufactured by UBM can be used as a dynamic spring constant measuring device. The dynamic spring constant is 1.5 g / μm or less, preferably 1.2 g / μm or less, and more preferably 0.8 g / μm or less. By keeping the dynamic spring constant within the above range, the gasket can have higher vibration damping and vibration isolation properties.

[0011] The hardness (Durometer A hardness) of the rubber contained in the elastic portion is preferably 90 or less, more preferably 85 or less, and even more preferably 80 or less. When the rubber hardness is within the above range, the gasket can have higher sealing performance and vibration damping and vibration isolation properties. The rubber hardness can be measured by a method conforming to JIS K6253.

[0012] A gasket according to one embodiment preferably comprises a metal plate and an elastic portion containing rubber having a dynamic spring constant of 1.5 g / μm or less on one or both sides of the metal plate. The material of the metal plate is not particularly limited, but includes iron, aluminum, copper, and alloys thereof. Examples of suitable materials include SPCC (cold-rolled steel plate), SPFC (cold-rolled high-tensile steel plate), mild steel, stainless steel plate, aluminum, and aluminum die-cast. Stainless steel plates include SUS301, SUS301H, SUS304, and SUS430. The thickness of the metal plate is not particularly limited, but is preferably 100 to 2000 μm, more preferably 200 to 1000 μm. The metal plate can be used in a degreased state, and the metal surface can be roughened, if necessary, by shot blasting, Scotch brazing, hairline finishing, dull finishing, or the like. The elastic portion may be bonded to the metal plate by including an adhesive component in the elastic portion or by providing an adhesive layer between the elastic portion and the metal plate. The adhesive components and adhesive layer components are not particularly limited as long as they can improve the adhesion between the metal plate and the elastic portion, but for example, resin-based vulcanizing adhesives such as phenolic resins and epoxy resins can be used. Examples of phenolic resins include any thermosetting phenolic resin, such as cresol novolac phenolic resin, cresol resol phenolic resin, and alkyl-modified phenolic resin. Examples of epoxy resins include cresol novolac epoxy resin, in which case bisphenol novolac phenolic resin is used as the curing agent and an imidazole compound is used as the curing catalyst.

[0013] The rubber constituting the elastic portion is preferably nitrile rubber (NBR). Nitrile rubber is a copolymer of butadiene and acrylonitrile. The nitrile rubber (NBR) may be hydrogenated or non-hydrogenated. As the nitrile rubber, various types of NBR may be used, including very high nitrile content (nitrile content of 43% or more), high nitrile content (36-42%), medium-high nitrile content (31-35%), medium nitrile content (25-30%), and low nitrile content (24% or less).

[0014] The rubber may further contain carbon black, silica, fillers, plasticizers, additives, antioxidants, vulcanizing agents, vulcanization accelerators, vulcanization aids, etc. The type of carbon black may be selected appropriately depending on the application of the gasket. For example, SAF carbon black, ISAF carbon black, HAF carbon black, EPC carbon black, XCF carbon black, FEF carbon black, GPF carbon black, HMF carbon black, SR carbon black, FT carbon black, MT carbon black, etc. may be used. Examples of additives include calcium metasilicate, calcium carbonate, zinc oxide, stearic acid, and wax. Furthermore, the vulcanizing agent is not particularly limited as long as it is used as a rubber vulcanizing agent, but examples thereof include sulfur-based vulcanizing agents and organic peroxide-based vulcanizing agents.

[0015] Examples of sulfur-based vulcanizing agents include powdered sulfur, sulfur flowers, precipitated sulfur, colloidal sulfur, highly dispersible sulfur, and insoluble sulfur; sulfur chloride, sulfur dichloride, morpholine disulfide, alkylphenol disulfide, dibenzothiazyl disulfide, N,N'-dithio-bis(hexahydro-2H-azenopine-2), phosphorus-containing polysulfides, and other sulfur-containing compounds. Examples of organic peroxide-based vulcanizing agents include ketone peroxides, peroxy esters, diacyl peroxides, and dialkyl peroxides. Vulcanization accelerators and vulcanization aids can also be used as needed.

[0016] FIG. 1 is an exploded perspective view of a housing to which an example of a gasket according to an embodiment is applied. The housing 100 shown in FIG. 1 is composed of two members: a case member 200 and a cover member 300. The case member 200 and the cover member 300 each have integral flanges 201, 301 around the periphery of their openings. A single gasket 1 is disposed between the opposing mating surfaces 202, 302 of the flanges 201, 301. The mating surfaces 202, 302 of the flanges 201, 301 are formed so as to surround the outer peripheries of the openings of the case member 200 and the cover member 300 in a band shape of a certain width. The portions where the bolt holes 203, 303 are formed partially protrude laterally.

[0017] The gasket 1 has an annular portion 1a and a protruding portion 1b. The annular portion 1a is formed with a constant width similar to that of the mating surfaces 202, 302 of the flange portions 201, 301 of the case member 200 and the cover member 300. The protruding portion 1b partially protrudes laterally from the annular portion 1a at positions corresponding to the bolt holes 203, 303 of the flange portions 201, 301, so as to be connected by a smooth curve. Bolt holes 11 corresponding to the bolt holes 203, 303 of the flange portions 201, 301 are formed in each protruding portion 1b.

[0018] The housing 100 is integrally fastened together by inserting bolts 400 into the bolt holes 203, 303, 11, thereby fastening the case member 200, the cover member 300, and the gasket 1 together. The gasket 1 sandwiched between the flange portions 201, 301 seals the gap between the butting surfaces 202, 302 of the flange portions 201, 301.

[0019] The gasket 1 is not particularly limited as long as it has the above configuration. In addition, in the above description, an example has been shown in which the gasket 1 according to one embodiment is applied as a sealing member between the flange portions 201, 301 of the case member 200 and the cover member 300 of the housing 100. However, the gasket 1 according to one embodiment is not limited to applications to such a housing 100, and can be widely applied to sealing the butted surfaces between two members.

[0020] The gasket is preferably a gasket for a motor, and is also preferably a gasket for an inverter case.

[0021] In one embodiment of the method for manufacturing a gasket, for example, a solution containing a rubber composition for the elastic portion is applied dropwise to a substrate such as a metal plate, and then the solution is heated to dry and vulcanize the rubber composition to produce the elastic portion. The solution containing the rubber composition for the elastic portion is not particularly limited, and examples of the solution that can be used include methyl ethyl ketone, toluene, and ethyl acetate. [Example]

[0022] Preferred embodiments of the present invention will be specifically described below based on examples and comparative examples, but the present invention is not limited to these examples.

[0023] (Examples 1 to 14 and Comparative Examples 1 to 5) A pressure kneader (manufactured by Nihon Spindle Co., Ltd.) and an open roll (manufactured by Kansai Roll Co., Ltd.) were used to mix the materials according to the formulation shown in Table 1 below, to prepare a rubber composition. (evaluation) The rubber compositions obtained as described above were subjected to the following measurements. (a) Measurement of hardness, tensile strength, and elongation of the elastic part The vulcanization rate of the rubber composition was measured in advance in accordance with JIS K6300-2. c (90) (90% vulcanization time) is measured. c Test specimens were prepared by pressurizing and vulcanizing the rubber composition under conditions exceeding (90). The test specimens were subjected to measurement of hardness (Durometer A hardness) in accordance with JIS K6253, and measurements of tensile strength and elongation in accordance with JIS K6251. (b) Measurement of dynamic spring constant The rubber composition was pressurized and vulcanized under the same conditions as in (a) above to prepare test specimens with a thickness of 2 mm, a width of 4 mm, and a length of 20 mm. The dynamic spring constant of the test specimens was then measured by the tensile method using a Rheogel-E4000 manufactured by UBM under the conditions of 23±2°C, 100 Hz, and a strain amplitude of 0.1%, in accordance with the forced vibration non-resonance method described in JIS K6394:2007. (c) Measurement of gasket loss factor The surface of a 400 μm-thick SPCC steel plate was treated with zinc phosphate. Then, methyl ethyl ketone (MEK) containing a phenolic resin (Sixon 715 (trade name)) was applied to the SPCC steel plate and then dried. The above rubber composition was then dissolved in methyl ethyl ketone (MEK). MEK containing the rubber composition was then applied to the SPCC steel plate after the MEK solution containing the phenolic resin had been applied, and the rubber composition was vulcanized in an oven at 200°C for 3 minutes to form an elastic portion with a thickness of 120 μm on the SPCC steel plate (metal plate). As a result, a gasket with a width of 17 mm and a length of 250 mm and having an elastic portion on the SPCC steel plate (metal plate) was obtained. The gasket thus obtained was attached to a 250 μm-thick, 17 mm-wide, and 250 mm-long SUS301 plate using a cyanoacrylate adhesive to obtain a sample for loss factor measurement. Furthermore, preliminary experiments confirmed that the type of adhesive used does not affect the loss factor value, as long as the gasket can be attached to the SUS301 plate. Next, using a Rion AS14PA5 (cantilever type), the loss factor was measured in accordance with JIS K7391:2008 using the half-width method, a measurement temperature of 23±2°C, and a second-order resonance frequency within the measurement range of 0 to 1 kHz. If the loss factor was 0.03 or higher, the vibration-damping and vibration-proofing properties were judged to be good and rated as "○", while if the loss factor was less than 0.03, the vibration-damping and vibration-proofing properties were judged to be poor and rated as "×". The composition of the rubber composition and the evaluation results of the vibration-damping and vibration-proofing properties are shown in Table 1 below.

[0024] [Table 1]

[0025] The names of the materials in Table 1 are as follows: Nitrile rubber A: Nipol (registered trademark) DN3350 (Zeon Corporation) Nitrile rubber B: JSR N237 (JSR Corporation) Nitrile rubber C: JSR N220S (JSR Corporation) Carbon black A (MT carbon black): THERMAX® N990 LSR (Cancarb) Carbon Black B (SRF Carbon Black): HTC#SS (Shin-Nichika Carbon Co., Ltd.) Carbon black C (SRF carbon black): ASAHI #50HG (Asahi Carbon Co., Ltd.) Carbon Black D (FEF Carbon Black): SEATO (registered trademark) SO (Tokai Carbon Co., Ltd.) Carbon black E (HAF carbon black): Showblack (registered trademark) N330L (Cabot Japan Co., Ltd.) Silica: Nipsil (registered trademark) LP (Tosoh Corporation) Filler A: Actidil VM56 (Hoffman Minerals) Filler B: Nyad® 400 (NYCO Minerals, Inc.) Filler C: Hakuenka (registered trademark) CC (Shiraishi Kogyo Co., Ltd.) Plasticizer: Adeka Cizer (registered trademark) RS107 (ADEKA Corporation) Additive A: Zinc oxide (Seido Chemical Industry Co., Ltd.) Additive B: DTST (Miyoshi Oil Co., Ltd.) Additive C: NOCRAC 810-NA (Ouchi Shinko Chemical Industry Co., Ltd.) Additive D: SUNTIGHT® R (Seiko Chemical Co., Ltd.) Vulcanizing agent A: Colloidal sulfur A (Tsurumi Chemical Industry Co., Ltd.) Vulcanizing agent B: Valnoc® R (Ouchi Shinko Chemical Industry Co., Ltd.) Vulcanizing agent C: Peroximon (registered trademark) F-40 (NOF Corporation) Vulcanization accelerator A: Noccela (registered trademark) TBZTD (Ouchi Shinko Chemical Industry Co., Ltd.) Vulcanization accelerator B: Noccela (registered trademark)-CZ-P (Ouchi Shinko Chemical Industry Co., Ltd.) Vulcanization aid: TAIC (registered trademark) M60S (Mitsubishi Chemical Corporation)

[0026] The results in Table 1 show that when the dynamic spring constant of the rubber that makes up the elastic part is 1.5 g / μm or less, the loss factor becomes 0.03 or more, resulting in a gasket with excellent vibration damping and isolation properties. [Explanation of symbols]

[0027] 1 gasket 1a Annular part 1b Protruding part 11 Bolt holes 100 cabinets 200 Case material 201, 301 flange 202, 302 butting surface 203, 303 bolt holes 300 Lid member 400 volts

Claims

1. A gasket having an elastic portion containing nitrile rubber with a nitrile content of 31 to 35%, which has a dynamic spring constant of 0.208 g / μm or more and 1.5 g / μm or less as measured under the conditions of 23±2°C, 100 Hz, and a strain amplitude of 0.1% as described in JIS K6394:2007.

2. 2. The gasket of claim 1, wherein the rubber has a hardness of 90 or less.

3. A metal plate; The elastic portion is provided on one or both sides of the metal plate.

3. The gasket of claim 1 or 2, wherein

4. 4. The gasket according to claim 1, which is a gasket for a motor.

5. The gasket according to claim 1 , which is a gasket for an inverter case.

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