JPH04246448A - Rubber vibration isolator - Google Patents

Abstract

PURPOSE:To provide a rubber vibration isolator having vibrationproofness and heat resistance more excellent than those of an NR rubber vibration isolator. CONSTITUTION:A rubber vibration isolator having a rubber part comprising a vulcanized rubber, wherein the rubber component of the vulcanized rubber is an ethylene/propylene rubber, and the rubber compound of the vulcanized rubber contains 2-20phr bivalent or trivalent metal salt of a lower unsaturated fatty acid.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to anti-vibration rubber. In particular, rubber parts attached to automobile chassis for the purpose of vibration isolation and cushioning, such as engine mounts (Fig. 1), strut mounts (Fig. 2), bumper rubbers (Fig. 3), and bush rubbers (Fig. 4). This is a suitable invention.

0002

2. Description of the Related Art Anti-vibration rubber is generally required to have excellent dynamic properties (particularly anti-vibration performance).

[0003] Conventional anti-vibration rubber for automobiles has been mainly made of natural rubber (NR) (containing NR as the rubber component or the main component), which has excellent anti-vibration performance.

[0004] On the other hand, as the interiors of automobile engine compartments have become hotter and smaller in recent years, rubber materials for automobile anti-vibration rubber have come to be required to have higher heat resistance and anti-vibration performance than ever before. It's here.

[0005]

[Problems to be Solved by the Invention] However, it has been difficult for the above-mentioned NR anti-vibration rubber to provide sufficient heat resistance and anti-vibration performance. Furthermore, it has been thought that it is difficult to obtain vibration damping performance comparable to that of NR vibration damping rubber with rubber materials other than NR.

[0006] In view of the above, an object of the present invention is to provide a vibration isolating rubber that is superior to NR vibration isolating rubber in terms of vibration isolating performance and heat resistance.

[0007]

[Means for Solving the Problems] The vibration-proof rubber of the present invention solves the above-mentioned problems by the following structure.

[0008] In the anti-vibration rubber in which the rubber portion is formed of vulcanized rubber, the rubber component of the vulcanized rubber is ethylene propylene rubber, and the rubber compound of the vulcanized rubber contains:
2 to 20 divalent or trivalent metal salts of lower unsaturated fatty acids
It is characterized by containing phr.

[0009]

[Detailed explanation of means]

(1) The anti-vibration rubber of the present invention has a prerequisite that the rubber portion 1 is formed of vulcanized rubber.

[0010] The forming method is that the metal part 3 prepared in advance is
is set in a mold, and the rubber part 1 is integrated with the metal part 3 by insert molding (usually by vulcanization adhesion). Also,
The metal part 3 and the rubber part 1 are prepared separately, and then integrated using a combination of adhesive and press-fitting (mechanical bonding) or only one of them.

(2) One of the characteristics of the present invention is that the rubber component of the vulcanized rubber is an ethylene propylene rubber. Here, as the ethylene propylene rubber, sulfur vulcanizable ethylene/propylene/nonconjugated diene terpolymer (EPDM) is usually used, but ethylene/propylene binary copolymer (EPM) is used. May be used.
(3) Another feature of the present invention is that the rubber compound contains 2 to 20 divalent or trivalent metal salts of lower unsaturated fatty acids.
The reason is that it contains phr. The amount of metal salt is
If it is less than 2 phr, no improvement in the heat resistance of the anti-vibration rubber can be expected, and if it exceeds 20 phr, the tackiness of the compounded rubber will become too high and molding workability will likely be adversely affected.

[0012] Examples of lower unsaturated fatty acids include acrylic acid, methacrylic acid, crotonic acid, and isocrotonic acid. Among these, acrylic acid,
Methacrylic acid is particularly preferred. In addition, examples of divalent metals include zinc, calcium, magnesium, ferrous iron, etc.
Examples of the valent metal include aluminum, boron, ferric iron, and the like.

Specifically, zinc acrylate, zinc methacrylate, etc. are desirable. (4) The above-mentioned rubber compound includes EPR, in addition to the above-mentioned metal salt, carbon black, which is usually blended into EPR-based rubber;
Zinc white, process oil, vulcanizing agent, vulcanizing aid, anti-aging agent, and other auxiliary materials are appropriately blended and kneaded to obtain a rubber material for anti-vibration rubber.

[0014]

Effects and Effects of the Invention Due to the above structure, the vibration isolating rubber of the present invention has vibration isolating performance comparable to that of NR vibration isolating rubber, as shown in the test examples described later, and has excellent heat resistance and vibration isolating properties. In terms of performance, it is far superior to NR anti-vibration rubber.

[0015]

[Example] Rubber materials were prepared from each rubber compound having the formulation shown in Table 1, and each test piece was prepared from each rubber material, and the following tests were conducted on each item.

The test results are shown below. In the case of EPDM vulcanized rubber (comparative example) that does not contain metal oxides, conventional N
Although the anti-vibration performance is inferior to that of R vulcanized rubber (reference example), Examples 1 and 2 containing metal salts are superior to NR not only in heat resistance but also in anti-vibration performance. I understand that.

(1) Normal physical properties: JIS K 6301
(Test piece: dumbbell shape No. 3), spring hardness: HS (JIS A), tensile strength: TB (k
gf/cm2) and elongation at break; EB (%).

(2) Vibration damping property: Evaluated by the ratio of dynamic elastic modulus (E'100HZ) and (GS) measured by the following method.

(1) Dynamic elastic modulus: Measured using a viscoelastic spectrometer manufactured by Iwamoto Seisakusho. (Frequency: 100Hz, dynamic strain: 0.5%, test piece: 5m
m strip) ■Static shear modulus: JIS low elongation stress test
K 6301, and calculated based on the following formula.

[0020] GS = 1.639 × TB (elongation: 2
5%, test piece: 5 mm strip) (3) Heat resistance: According to JIS K 6301 (test piece: dumbbell shape No. 3), an air heating aging test was conducted under the conditions of 120°C x 70 hours. Measurement items are spring hardness; △HS (scale difference), tensile strength; △TB (%)
, Breaking elongation; EB (%) (4) Compression set resistance: A compression set test was conducted in accordance with JIS K 6301 under heat treatment conditions of 120°C x 70 hours, and the compression set rate; CS (%) I asked for

[0021]

[Table 1]

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an engine mount showing an example of an application of the present invention.

FIG. 2 is a sectional view of a strut mount showing another example.

FIG. 3 is a sectional view of a bumper rubber showing still another example.

FIG. 4 is a sectional view of a bush rubber showing still another example.

[Explanation of symbols]

1 Rubber part of anti-vibration rubber 3. Metal part of anti-vibration rubber

Claims (2)

[Claims] 1. A vibration-proof rubber whose rubber portion is formed of vulcanized rubber, wherein the rubber component of the vulcanized rubber is an ethylene propylene rubber, and the rubber compound of the vulcanized rubber contains lower grade impurities. Divalent or trivalent metal salts of saturated fatty acids are
Anti-vibration rubber characterized by containing 20 phr. 2. The vibration-proof rubber according to claim 1, wherein the lower unsaturated fatty acid is acrylic acid or methacrylic acid.