JP4172407B2 - Liquid filled damper - Google Patents

Description

  The present invention relates to a liquid-filled damper that encloses a liquid such as silicone oil and absorbs vibration energy based on the flow of the liquid to provide a vibration-proofing action.

When a CD player is mounted on a vehicle such as an automobile, if vibration generated while the vehicle is running is transmitted to the CD player as it is, a skipping sound is generated. A damper for absorbing the vibration is interposed between the pickup support portion and the CD player casing portion or between the support member on the vehicle body side and the supported member on the CD player main body side. Conventionally, various types of dampers have been proposed. In particular, a liquid-filled damper in which a high-viscosity liquid such as silicone oil is sealed inside a container with a rubber (or soft resin) elastic wall is preferred because of its excellent vibration absorption performance. Used for. The present applicant has also proposed several types of liquid-filled dampers (see, for example, Patent Documents 1 to 3). Among them, the liquid-filled damper described in Patent Document 1 uses butyl rubber, which is inexpensive and excellent in heat resistance, as the material of the elastic wall in the container, and is suitable in terms of product cost and heat resistance.
Japanese Utility Model Publication No. 2-91234 Japanese Patent Laid-Open No. 7-71507 JP-A-8-184345

  However, butyl rubber usually has a vulcanization system as a sulfur vulcanization system. Therefore, when a liquid-filled damper formed using butyl rubber as described above is used in an environment with a high temperature such as a vehicle. The heat may cause sulfur to be released from the butyl rubber (elastic wall). When sulfur is liberated in this way, the phenomenon that the silver plating contact inside the device (CD player or the like) on which the liquid-filled damper is mounted appears black due to the action of the sulfur. Therefore, there is a demand for reducing the amount of sulfur in the vulcanizing agent in the material of the elastic wall of the liquid-filled damper. However, if the amount of sulfur is reduced until the above phenomenon does not appear, there is a problem in that this leads to a deterioration in durability (wear resistance) of the liquid-filled damper because the crosslinking density is lowered.

  On the other hand, from the viewpoint of maintaining durability and the like, generally, an amine-based antioxidant is blended in the elastic wall material. However, amine-based anti-aging agents have high colorability, and contamination of silver-plated contacts and the like resulting therefrom is regarded as a problem.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a liquid-filled damper that is excellent in durability, vibration absorption, and the like, without being accompanied by contaminants.

In order to achieve the above object, the liquid-filled damper of the present invention is sealed in a sealed space formed by a main body part, at least a part of which is constituted by an elastic wall, a bottom part thereof, and the main body part and the bottom part. A liquid-filled damper comprising a liquid, wherein the elastic wall is made of a rubber composition having the following (A) to (C) as essential components, and the total sulfur of the elastic wall formed by the rubber composition: The content is 0.8% by weight or less.
(A) Butyl rubber.
(B) At least one of a phenolic antioxidant and an imidazole antioxidant .
(C) Poly-p-dinitrosobenzene.

  That is, the present inventors have made extensive studies focusing on the elastic wall portion that exhibits the damper performance in order to solve the above-mentioned problems. In the course of the research, it is necessary to reduce the total sulfur content of the elastic wall to 0.8% by weight or less in order to prevent the blackening phenomenon of the silver plating contact as described above from appearing. Something has been found through numerous experiments. Further, as a result of various studies, it has been found that the reduction in the crosslinking density of the butyl rubber due to the reduction of the sulfur content can be eliminated by adding poly-p-dinitrosobenzene (DNB). Furthermore, since contamination of silver-plated contacts due to the use of an amine-based anti-aging agent cannot be ignored, it has been found that non-contaminating anti-aging agents such as a phenol-based anti-aging agent can be used as an alternative material. From these research results, the elastic wall is formed using butyl rubber, non-staining antiaging agent, and DNB, and the total sulfur content of the elastic wall is 0.8% by weight or less. As a result, the inventors have found that the performance (durability, etc.) required as a liquid-filled damper can be satisfied without contaminating the silver-plated contacts, and the present invention has been achieved.

  As described above, the liquid-filled damper of the present invention includes a main body part, at least a part of which is formed of an elastic wall, a bottom part thereof, and a silicone oil sealed in a sealed space formed by the main body part and the bottom part. It consists of a liquid, and the vibration absorption performance is exhibited in the elastic wall. And since the said elastic wall is formed with the butyl-type rubber, it is low-cost and excellent in heat resistance. Moreover, since the total sulfur content of the elastic wall is kept low and no contamination type anti-aging agent such as an amine type anti-aging agent is used, the silver plating inside the apparatus mounting the liquid-filled damper is used. Blackening and contamination of contacts etc. will be resolved. Further, since DNB is contained in the elastic wall material, a sufficient crosslinking density can be obtained even with low sulfur, and as a result, durability is excellent. Therefore, the liquid-filled damper of the present invention can effectively suppress vibration, has high durability, and is excellent from the viewpoint of quality reliability. For example, sound skipping of a CD player mounted on a vehicle or the like Demonstrates excellent prevention performance.

In particular, the present invention, the non-pollution antioxidant is of at least one in which this phenolic antioxidant and an imidazole-based anti-aging agents, without contamination inside the apparatus for mounting the liquid-filled damper, It becomes possible to effectively improve the heat aging resistance.

  Further, in the rubber composition forming the elastic wall, when the content ratio of the DNB is set in a specific range, the durability can be effectively improved without impairing the flexibility of the elastic wall. It becomes like this.

  Next, an embodiment of the present invention will be described.

  The liquid-filled damper 1 of the present invention includes, for example, a main body portion 2 that is at least partially constituted by an elastic wall 3, a bottom portion 4, and the main body portion 2 and the bottom portion 4 as shown in a cross-sectional view of FIG. And a liquid 5 sealed in a sealed space. And the said elastic wall 3 consists of a rubber composition which has a butyl-type rubber (A component), a nonfouling anti-aging agent (B component), and DNB (C component) as an essential component, The total sulfur content of the formed elastic wall 3 is regulated to 0.8% by weight or less. Here, the essential component refers to an optional component, which is a component that is necessarily contained in terms of configuration, and is not subject to quantitative restrictions. In the figure, the elastic wall 3 has a substantially dome shape, but the present invention is not particularly limited to such a shape.

  In the present invention, the total sulfur content of the elastic wall 3 needs to be set to 0.8 wt% or less as described above. Preferably, it is set to 0.7% by weight or less. That is, by setting the total sulfur content of the elastic wall 3 within this range, it is possible to eliminate the blackening phenomenon of the silver plating contact. Here, the total sulfur content of the elastic wall 3 includes not only the vulcanizing agent but also all sulfur components contained in the vulcanization accelerator, oil, carbon black and the like. Therefore, the total sulfur content of the elastic wall 3 is obtained by, for example, pretreating a sample collected from the elastic wall 3 according to JIS K 6233-1 (ISO 6528-1) (hydrogen peroxide by an oxygen combustion flask method). This can be confirmed by adsorbing a sulfur component to the solution) and performing a quantitative analysis of sulfur by ion chromatography using the resulting sulfur adsorption solution.

  In the low sulfur elastic wall 3 as described above, butyl rubber (IIR) or halogenated butyl rubber (Cl-IIR, Br-IIR) is used as butyl rubber (A component) as an essential material. A blended rubber blended up to 20% by weight can be mentioned.

In the present invention, a non-staining anti-aging agent (component B) is used together with the butyl rubber (component A). Here, the non-pollution antioxidant, have had a never contaminate the silver-plated contacts as such as an amine-based antiaging agent uncontaminated antioxidant, specifically, bisphenol-based, such as mono-phenolic Phenol-based anti-aging agents and imidazole-based anti-aging agents are used . These non-polluting anti-aging agents are used alone or in combination of two or more.

  The content ratio of the non-staining anti-aging agent (component B) is preferably in the range of 1 to 10 parts, particularly preferably 100 parts by weight (hereinafter abbreviated as “part”) of butyl rubber (component A). Within the range of 2-6 parts. That is, if the content ratio of the non-polluting anti-aging agent is less than 1 part, the effect of improving ozone resistance and heat resistance is poor, and conversely, if it exceeds 10 parts, the workability tends to deteriorate. is there.

  Furthermore, DNB (C component) is used as an essential component material together with the butyl rubber (A component) and the non-staining anti-aging agent (B component).

  The content ratio of the DNB (component C) is preferably in the range of 0.1 to 1 part, particularly preferably in the range of 0.2 to 0.7 part, with respect to 100 parts of the butyl rubber (component A). It is. That is, when the content ratio of the DNB (component C) is less than 0.1 part, the effect of improving the product durability due to setting the total sulfur content low is poor. This is because there is a tendency to decrease.

  In addition to the above-mentioned components, the elastic wall 3 may be made of a reinforcing agent such as carbon black, a filler, or a crosslinking aid, as long as it does not impair the characteristics such as low sulfur extractability targeted by the present invention. , Antioxidants, processing aids, flame retardants and the like may be contained as appropriate.

  By the way, in the present invention, the elastic wall 3 constitutes a part or all of the main body 2. In FIG. 1, the entire main body 2 is formed of the material of the elastic wall 3. However, depending on the case, a portion where rigidity is required [a portion other than the portion exhibiting the damper performance (for example, a cylindrical portion on the side surface) is made of a material such as polypropylene, polyamide, acrylonitrile butadiene styrene copolymer (ABS), or the like. The main body 2 may be formed by bonding to the elastic wall 3.

  A material that can be fixed to the main body 2 is selected as a material for forming the bottom 4. Examples of such a material include ABS, polystyrene, acrylonitrile styrene, polymethyl methacrylate, polycarbonate, and polyvinyl chloride. The main body 2 and the bottom 4 are usually formed separately, and after the liquid 5 is sealed, they are integrated by bonding with an adhesive or the like. As the liquid 5, a highly viscous liquid such as silicone oil is used. These may be used alone or in combination of two or more. The liquid 5 may be appropriately mixed with powder such as silicone powder.

  Although the manufacturing method of the liquid enclosure damper 1 of this invention is not specifically limited, For example, it can produce as follows. That is, first, each component material of the elastic wall 3 as described above is prepared, and these are kneaded using a kneader such as a roll, a kneader, a Banbury mixer, a twin-screw kneading extruder, etc. Prepare the material. In the present invention, when DNB is added at the mastication stage of the butyl rubber in the preparation of the elastic wall 3 material, the reaction at the time of preparation becomes smooth, and there is no variation in the physical properties of the product. At this stage, the viscosity of the rubber rises moderately, so that workability improvement based on this is also seen. Therefore, it is preferable to add DNB at such timing. Next, the main body 2 is formed by injection molding into a mold using the elastic wall 3 material thus obtained. Subsequently, a liquid 5 such as silicone oil is injected into the main body 2. On the other hand, a bottom portion 4 molded with a predetermined material is separately prepared. Then, the liquid 4 is covered with the bottom 4 so as to seal the injected liquid 5 (in this case, the main body 2 and the bottom 4 are fixed by adhesion with an adhesive or the like), thereby achieving the intended liquid-filled damper 1. Can be obtained.

  As shown in FIG. 1, the liquid-filled damper 1 is provided with a recess 3 b for fitting and fixing a support shaft provided on either the supported member or the support member on the elastic wall 3. This is preferable because it is excellent in stability and the like. In addition, the said recessed part 3b is a part of elastic wall 3, and is shape | molded by the shape of the metal mold | die used at the time of elastic wall 3 shaping | molding. The concave portion 3b may be formed so as to be thin like the other portions, but it is preferable that the concave portion 3b be formed thick so as not to be broken by the support shaft. Further, when the elastic wall 3 is formed in a substantially dome shape as shown in the figure, if the concave portion 3b is formed in the top portion 3a, the vibration isolation performance is more effectively exhibited.

  Here, the usage example of the said liquid enclosure damper 1 is demonstrated based on FIG. In the figure, reference numeral 6 denotes a supported member, which has a claw portion 6a that fits and is fixed to the fixing groove 3c of the liquid-filled damper 1. 7 is a support member (6 may be a support member and 7 may be a supported member). The liquid-filled damper 1 is attached to the supported member 6 as shown in the figure, and the support shaft 8 fixed to the support member 7 is fitted into the recess 3b provided in the elastic wall 3. . In such a state, by interposing the liquid-filled damper 1 between the supported member 6 and the supporting member 7, it is possible to absorb vibration between them.

  The shape and size of the liquid-filled damper 1 of the present invention are not particularly limited, but are usually formed so that the bottom surface has a diameter of about 15 mm and a height of about 13 mm. . And the thickness of the elastic wall 3 is normally set to the range of 0.1-1.0 mm, and is suitably set to the range of 0.2-0.6 mm.

  Since the liquid-filled damper 1 of the present invention has heat resistance in addition to its excellent vibration absorption performance, an on-vehicle electronic device (in particular, a CD player, a CD-ROM, a DVD-ROM, or a hard disk) is used. The use of the product of the present invention is not limited to this. For example, a hard disk drive for PC and an optical disk drive (CD-) for PC are used. It can also be used for image stabilization such as a ROM drive.

  Next, examples will be described together with comparative examples.

  First, prior to the examples and comparative examples, the following materials were prepared.

[Butyl rubber (component A)]
Polycerbutyl 301, manufactured by Bayer

〔stearic acid〕
LUNAC S-30, manufactured by Kao

[Zinc flower]
2 types of zinc oxide manufactured by Mitsui Mining & Smelting Co., Ltd.

[Amine-based anti-aging agent]
Ozonon 6C, manufactured by Seiko Chemical Co., Ltd.

[Non-polluting anti-aging agent (component B)]
NOCRACK NS6 (phenolic anti-aging agent), manufactured by Ouchi Shinsei Chemical Co., Ltd.

[Microcrystalline wax]
Suntite S, manufactured by Seiko Chemical Co., Ltd.

[SRF carbon]
Seast GS, manufactured by Tokai Carbon

[Paraffin oil]
JOMO P200, manufactured by Japan Energy

[Lubricant]
Stractol WB-16, manufactured by Schill & Seilacher

[DNB-containing cross-linking agent (contains DNB as component C)]
Balnock DNB (DNB base 25% by weight, wax 75% by weight), manufactured by Ouchi Shinsei Chemical Co., Ltd.

〔sulfur〕

[Vulcanization accelerator (i)]
Sunseller CZ-G, manufactured by Sanshin Chemical Industry Co., Ltd.

(Vulcanization accelerator (ii))
Accelerator TL-ptc, manufactured by Kawaguchi Chemical Co., Ltd.

[Examples 1-3, Comparative Examples 1-2]
Each material shown above was prepared so that it might become the ratio shown in Table 1 of the postscript, and materials other than the vulcanization accelerator and sulfur were masticated using a Banbury mixer. And after the said mastication process, this thing was moved to the open roll, and also the said vulcanization accelerator and sulfur were added and knead | mixed, and the material for elastic walls was prepared. Using the elastic wall material thus obtained, an approximately dome-shaped main body having an elastic wall (thickness 0.4 mm) was produced by injection molding into a predetermined mold. In addition, the recessed part (thickness 1.4mm) for inserting and fixing a support shaft was provided in the top part of the said main-body part. Then, silicone oil (SH200, viscosity: 0.5 m ² / s, manufactured by Toray Dow Corning Silicone) is injected into the main body by a mandrel, and then a lid is formed by a separately manufactured ABS resin bottom. Then, the cylindrical part and the bottom part were fixed by ultrasonic welding to obtain a target liquid-filled damper (bottom diameter 15 mm, height 13 mm, see FIG. 1). The total sulfur content of the elastic wall was measured according to the following criteria, and the value is also shown in Table 1 below.

[Total sulfur content]
A sample collected from the elastic wall is pretreated according to JIS K 6233-1 (ISO 6528-1) (the sulfur component is adsorbed to the hydrogen peroxide solution by the oxygen combustion flask method), and the sulfur adsorption obtained thereby. The total sulfur content (% by weight) was measured by quantitative analysis of sulfur by ion chromatography using the solution.

  Using the liquid-filled dampers thus obtained, each characteristic was evaluated according to the following criteria. These results are shown in Table 2 below.

[Silver board contamination]
The obtained liquid-filled damper was left in a high-temperature atmosphere (85 ° C.) for 168 hours, and the contamination state of the silver plate (1 cm × 1 cm) placed 20 mm away from the liquid-filled damper was visually observed. In the evaluation, a case where there was no contamination such as a black phenomenon was marked with ◯, and a case where contamination was seen was marked with ×.

[Product durability]
The obtained liquid-filled damper was attached to a measurement system (see FIG. 2), and vibration was applied in a normal temperature atmosphere (20 to 25 ° C.) according to the following vibration conditions. And the condition of the elastic wall after that was observed visually. In the evaluation, a case where no crack or breakage was observed on the elastic wall was indicated by ○, and a case where a crack or breakage was observed was indicated by ×.
Acceleration: 29.4 m / s ²
Excitation frequency: 10 to 100 Hz,
Frequency sweep rate: 7.5 min / single sweep
Excitation direction: Vertical, front / rear, left / right direction Excitation time: 8 hours in each direction

  From the result of the said table | surface, since the elastic wall of the Example goods is low sulfur, it turns out that the silver board contamination is eliminated. It can also be seen that the product durability is excellent despite the low sulfur content.

  On the other hand, in Comparative Example 1, since the sulfur content in the elastic wall is increased and the amine-based anti-aging agent is used, it is inferior to the example product in the evaluation of silver plate contamination. .

  In Comparative Example 2, since the total sulfur content was set as low as that in the Examples, the evaluation of the contamination of the silver plate was good, but a sufficient crosslinking density was not obtained and the product durability was poor. . In Comparative Example 2, an attempt was made to supplement the reinforcement by increasing the amount of carbon black. However, it was found that the product durability required in the present invention was not obtained.

It is sectional drawing which shows an example of the liquid enclosure damper of this invention. It is explanatory drawing which shows the attachment state of the liquid enclosure damper of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid enclosure damper 2 Main-body part 3 Elastic wall 4 Bottom part 5 Liquid

Claims (2)

A liquid-filled damper comprising a main body part at least partially constituted by an elastic wall, a bottom part thereof, and a liquid sealed in a sealed space formed by the main body part and the bottom part, wherein the elastic wall comprises: A liquid composition comprising a rubber composition comprising the following (A) to (C) as essential components, wherein the total sulfur content of an elastic wall formed from the rubber composition is 0.8% by weight or less Damper.
(A) Butyl rubber.
(B) At least one of a phenolic antioxidant and an imidazole antioxidant .
(C) Poly-p-dinitrosobenzene. In the rubber composition, the content ratio of the poly-p-dinitrosobenzene of the component (C) is set in a range of 0.1 to 1 part by weight with respect to 100 parts by weight of the butyl rubber of the component (A). claim 1 liquid filled damper that is.