JPH0972365A - Vibration-proof rubber bush and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To dispense with the adhesion treatment to an intermediate sleeve for eliminating the process required for the adhesion, and to apply a sufficient preliminary compression even to the rubber elastic body on the inside of the intermediate sleeve when such a treatment as drawing and press-fitting after vulcanization is applied. SOLUTION: A cylindrical rubber elastic body 16 is arranged between an inner cylindrical member 12 and an outer cylindrical member 14 for fixing the inner cylindrical member 12 and the outer cylindrical member 14, and also an intermediate sleeve 18 consisting of PPE resin is concentrically embedded and fixed to the intermediate part in the thickness direction of the rubber elastic body 16. In manufacturing a vibration-proof rubber bush 10, precompression is wholly and uniformly applied to the inside rubber elastic body part 16B on the basis of the elastic deformation in the diameter-reducing direction of the intermediate sleeve 18 at the time when drawing, press-fitting, or the like after vulcanization have been applied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration-proof rubber bush and a method for manufacturing the same.

[0002]

2. Description of the Related Art
A vibration-proof rubber bush in which a tubular rubber elastic body is fixed to the outer side of the inner tubular metal fitting is widely used as a vibration-proof member in a vehicle suspension device or the like. In this type of anti-vibration rubber bush, an intermediate sleeve (interring) is concentrically embedded in the rubber elastic body at a middle portion in the thickness direction, and the reinforcing effect of the intermediate sleeve (interring)
The spring constant ratio in the direction perpendicular to the axis is set large.

Conventionally, a metal one has been used as the intermediate sleeve, and the intermediate sleeve is
When the inner cylinder metal fitting is set in the mold cavity and the rubber material is injected into the cavity and vulcanization molding is performed to manufacture the anti-vibration rubber bush, the rubber inside and outside the intermediate sleeve is sufficiently rubberized. Slits are typically provided to allow the material to wrap around and flow.

By the way, when a metal sleeve is used as the intermediate sleeve as described above, it is necessary to perform a bonding treatment on the intermediate sleeve in advance in order to vulcanize and bond the intermediate sleeve and the rubber elastic body.

However, in this adhesion treatment, two kinds of adhesives, an undercoating adhesive and a topcoating adhesive, have to be applied after surface treatment such as blasting and chemical conversion coating, and in addition, the adhesives have been applied. Since the subsequent drying process is also required, the number of steps for manufacturing the vibration-proof rubber bush increases, which is a factor of increasing the manufacturing cost. Further, when the intermediate sleeve and the rubber elastic body are fixed to each other with an adhesive, there remains a problem of reliability of adhesion, and there is a problem that durability is adversely affected if the adhesive is left uncoated.

In the vibration-proof rubber bush, for the purpose of improving durability after vulcanization molding, processing such as squeezing and press-fitting is performed, that is, a pressing elastic force is applied from the outer peripheral surface side in the diameter reducing direction to the rubber elastic body. It is common to add precompression. At that time, the slit provided in the intermediate sleeve acts as a portion for transmitting the compressive force.

That is, the compressive force generated in the outer rubber elastic body portion of the intermediate sleeve is transmitted to the inner rubber elastic body portion through the slit, whereby not only the outer rubber elastic body portion of the intermediate sleeve but also the inner rubber elastic body portion. Pre-compression is also applied to the body part.

However, in this case, a large strain is generated in the rubber elastic body in the vicinity of the slit, and when a repetitive force is applied during use of the anti-vibration rubber bush, there is a problem that cracks are easily generated and progress from this portion. Slitting a metal pipe requires a lot of man-hours, which is a cost problem.

On the other hand, it has been proposed to use a polyamide resin as an intermediate sleeve in such a vibration-proof rubber bush. This polyamide intermediate sleeve has better adhesion to the rubber elastic body than those made of other resin materials, but on the other hand, in the case of such a polyamide intermediate sleeve, vulcanization molding of the anti-vibration rubber bush is performed. At times, specifically, there is a difficult problem that the rubber elastic body is deformed by heat and pressure during vulcanization molding.

The vulcanization molding temperature of the anti-vibration rubber bush is as high as 140 to 160 ° C., and a large pressure due to the injection of the rubber material acts on the intermediate sleeve during vulcanization molding. The intermediate sleeve is deformed by heat and pressure. If the intermediate sleeve is deformed, the original function of the intermediate sleeve is not exerted, and the spring characteristics and durability of the anti-vibration rubber bush cannot be obtained as designed.

As measures against this, (a) a method of increasing rigidity by thickening the intermediate sleeve or forming ribs, (b) a method of changing vulcanization molding conditions (low temperature vulcanization and long time), or ( C) A method of adding a rubber material injection gate to the molding die in order to weaken the pressure acting on the intermediate sleeve during vulcanization molding can be considered, but in the case of (a) there are many dimensional restrictions, In addition, there is a problem that it is difficult to give sufficient rigidity to the intermediate sleeve. In addition, in the case of the method (b), the vulcanization molding time becomes long, and in the case of the method (c), the mold design It is difficult to add a gate or there is a problem of deburring at the gate part,
Not only do they impede the mass productivity of the anti-vibration rubber bushes, but even if countermeasures are taken, deformation of the intermediate sleeve cannot be prevented sufficiently.

[0012]

The invention of the present application has been made to solve such a problem. Thus, the first aspect of the present invention relates to a vibration-proof rubber bush, wherein a cylindrical rubber elastic body is fixed to the outer peripheral surface of the rigid inner tubular member, and the elastic rubber body is made of PPE resin at an intermediate portion in the thickness direction. The intermediate sleeve is embedded and fixed in the rubber elastic body (claim 1).

According to a second aspect of the present invention, in the vibration-proof rubber bush according to the first aspect, the intermediate sleeve made of the PPE resin has a reinforcing glass fiber based on the PPE base polymer.
It is characterized in that it is contained in the range of 25 wt% (claim 2).

A third aspect of the present invention relates to a method of manufacturing a vibration-proof rubber bush, wherein the rigid inner cylinder member and the intermediate sleeve are set in a cavity of a molding die, and a rubber material is injected into the cavity to form the rubber elastic body. At the same time as the vulcanization molding, the intermediate sleeve is integrated with the rigid inner cylinder member and the intermediate sleeve, and then the molded product is subjected to press-fitting, drawing, etc., to apply a compressive deformation force from the outer peripheral surface side in the diameter reducing direction. The outer peripheral side and the inner peripheral side of the rubber elastic body are pre-compressed (claim 3).

[0015]

As described above, the present invention is characterized in that the sleeve of the vibration-proof rubber bush is made of PPE resin. Here, the PPE resin is a thermoplastic resin composition containing polyphenylene ether as a main component and blended with polyalkenylene, a styrene polymer and the like. This PPE resin is a vibration-proof rubber bush, specifically a rubber elastic body, particularly SB
The rubber elastic body containing R has a feature that it can be integrally bonded with the rubber elastic body during vulcanization molding (based on the thermal compatibility of the polymer). Therefore, according to the present invention, it has been conventionally required. It is possible to eliminate the need for the bonding process for the intermediate sleeve, which can omit the process required for the bonding process, which can significantly improve the productivity of the vibration-proof rubber bush and reduce the cost.

This PPE resin also has the features of high deformation resistance at high temperatures and excellent elastic deformability at room temperature. That is, according to the present invention, it is possible to prevent the intermediate sleeve from being deformed by heat or the injection pressure of the rubber material during the vulcanization molding of the anti-vibration rubber bush, and therefore, the intermediate sleeve can fully exhibit its original function. It is possible to add spring characteristics and durability to the anti-vibration rubber bush as designed, and to reduce the elastic deformation of the intermediate sleeve when the anti-vibration rubber bush is subjected to processing such as drawing and press fitting at room temperature. Based on the above, it is possible to obtain an excellent effect that the rubber elastic body portion inside the intermediate sleeve can be sufficiently and uniformly pre-compressed.

In the present invention, it is desirable that the PPE resin contains reinforcing glass fibers (claim 2). In this case, the thermal deformation resistance of the PPE resin can be effectively increased by containing the reinforcing glass fiber in an amount of 5% or more. On the other hand, if the content exceeds 25%, the thermal deformation resistance increases, but the adhesiveness decreases to an undesired level.

According to a third aspect of the present invention, after the vibration-proof rubber bush is vulcanized and molded, a pre-compression is applied to the rubber elastic body by applying a pressure-deformation force in the diameter-reducing direction to the vibration-proof rubber bush. According to this, by utilizing the large elastic deformability of the intermediate sleeve made of PPE resin, the rubber elastic body portion inside the intermediate sleeve can be pre-compressed sufficiently and uniformly over the entire area. The durability performance of the vibration rubber bush can be effectively enhanced.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described in detail with reference to the drawings. In FIG. 1, reference numeral 10 denotes a vibration-proof rubber bush of this example, which has a cylindrical inner tubular metal fitting 12 as a rigid inner tubular member and a cylindrical outer tubular metal fitting 14 as a rigid outer tubular member.
And a cylindrical rubber elastic body 16 interposed between them and vulcanized and bonded to each of the inner tubular member 12 and the outer tubular member 14. The material of the rubber elastic body 16 is NR.
/ SBR system.

An intermediate sleeve 18 made of PPE resin is provided inside the rubber elastic body 16 at an intermediate position in the thickness direction thereof.
Are embedded concentrically, and this intermediate sleeve 18 divides the rubber elastic body 16 into an outer rubber elastic body portion 16A and an inner rubber elastic body portion 16B.

However, in the intermediate sleeve 18, as shown in detail in FIG. 2, small-diameter through holes 20 are formed evenly over substantially the entire surface, and the outer rubber elasticity of the intermediate sleeve 18 is formed through the through holes 20. The body portion 16A and the inner rubber elastic body portion 16B are connected to each other.

Here, the intermediate sleeve 18 is adhesively fixed to the rubber elastic body 16 without using an adhesive. The adhesion between the intermediate sleeve 18 and the rubber elastic body 16 is based on the thermal compatibility of the polymer at the interface.

The anti-vibration rubber bush 10 can be manufactured, for example, as follows. That is, the inner cylinder metal fitting 1
2. The outer cylinder fitting 14 and the intermediate sleeve 18 are set in the cavity of the molding die in a heated state, and in that state, the rubber material is injected into the cavity of the molding die by injection molding and vulcanization molding is performed.

At this time, the injection and vulcanization molding temperature of the rubber material is a high temperature of about 140 to 160 ° C., and the intermediate sleeve 18 made of PPE resin and the rubber elastic body 16 are simultaneously bonded and integrated during the vulcanization molding. It

Further, during injection and vulcanization molding of the rubber material, the rubber material injected into the cavity is sufficiently flown from the outside to the inside through the through hole 20 of the intermediate sleeve 18 and thereby flows into the outside rubber. The elastic body portion 16A and the inner rubber elastic body portion 16B are connected to each other through the through hole 20, and the flow of the rubber material through the through hole 20 reduces the action of pressure when the rubber material is injected into the intermediate sleeve 18. And intermediate sleeve 1
The deformation of No. 8 is suppressed.

In this example, the intermediate sleeve 18 contains 20% by weight of the reinforcing glass fiber based on the base polymer, and as a result, the thermal deformation resistance of the intermediate sleeve 18 is increased. However, if the content of the reinforcing glass fiber is too large, the adhesion with the rubber elastic body 16 is hindered,
On the other hand, if the amount is too small, the degree of improvement in the thermal deformation resistance of the intermediate sleeve 18 decreases.

FIG. 3 shows the relationship between the content of the reinforcing glass fiber (GF) and the thermal deformation resistance and adhesiveness. As shown in the figure, the thermal deformation resistance and the adhesiveness are in a contradictory relationship. When the content of the reinforcing glass fiber increases, the thermal deformation resistance increases, but the adhesiveness decreases. This is because the adhesion between the intermediate sleeve 18 and the rubber elastic body 16 is due to the compatibility of the polymer under heating.

The content of the reinforcing glass fiber contained in the intermediate sleeve 18 in the vibration-proof rubber bush of the present invention is 5% at which the heat distortion temperature is increased by 10 ° C. or more, so that the adhesive force does not include the reinforcing glass fiber. About half 25
It is preferable that the range is up to%.

The anti-vibration rubber bush 10 of this example is vulcanized and molded as described above and then subjected to processing such as drawing and press-fitting, that is, a processing of applying a pressure deforming force from the outer peripheral surface in a diameter reducing direction. The elastic body 16 is used with the precompression added thereto. As a result, good durability is imparted to the vibration-proof rubber bush 10.

In the case of the anti-vibration rubber bush 10 of the present embodiment, the intermediate sleeve 18 made of PPE resin has an excellent elastic deformability, so that only the outer rubber elastic body portion 16A is subjected to the processing such as drawing and press fitting. In addition, the pre-compression is sufficiently applied to the inner rubber elastic body portion 16B.

That is, in the anti-vibration rubber bush 10 of this example, the intermediate sleeve 18 exhibits good thermal deformation resistance during vulcanization to prevent the intermediate sleeve 18 from being deformed by heat and pressure, but at room temperature. During processing such as drawing and press fitting, the intermediate sleeve 18 is elastically deformed favorably and the rubber elastic body 16
To evenly pre-compress.

FIG. 4 shows such excellent features of the vibration-proof rubber bush 10 of this embodiment in comparison with the case where a polyamide intermediate sleeve is used. As shown in FIG. 4, the intermediate sleeve 18 made of PPE resin has a higher flexural modulus, that is, thermal deformation resistance under a high temperature condition during vulcanization molding, as compared with the intermediate sleeve made of polyamide (PA) resin. On the other hand, it can be seen that the bending elastic modulus is small and the elastic deformability is excellent at a temperature of 60 ° C. or lower, which is the use temperature of the product. The vibration-proof rubber bush 10 of this example skillfully utilizes such a feature of the intermediate sleeve made of PPE resin.

FIG. 6 shows that at room temperature (2
The results of a compression test of the intermediate sleeve 18 alone in the direction perpendicular to the axis at 3 ° C. are shown as PA resin (polyamide resin).
It is shown in comparison with the intermediate sleeve consisting of (However, this test was conducted on the intermediate sleeve 18 in which the through hole 20 is not formed). The intermediate sleeve made of PPE resin contained 20% reinforced glass fibers, and the intermediate sleeve made of PA resin used 30% reinforced glass fibers.

From these results, in the case of the intermediate sleeve 18 made of PPE resin, the elastic deformability is higher by about 20% at room temperature than that of the intermediate sleeve made of PA resin, and therefore a large reserve is provided for the inner rubber elastic body portion 16B. It will be appreciated that compression can be provided.

As described above, according to this embodiment, the bonding process for the intermediate sleeve 18, which has been conventionally required when manufacturing the vibration-proof rubber bush 10, can be omitted, and the process required for the bonding process can be omitted. Therefore, the productivity of the vibration-proof rubber bush 10 can be significantly increased, and the cost can be reduced.

In addition, upon squeezing or press-fitting after vulcanization, the inner rubber elastic body portion 16B can be sufficiently and uniformly pre-compressed based on the elastic deformability of the intermediate sleeve 18. Thus, the durability performance of the vibration-proof rubber bush 10 can be effectively enhanced.

In the above example, the circular through hole 20 is formed in the intermediate sleeve 18, but FIG.
As shown in (A), a through hole 22 extending in the circumferential direction is formed in the intermediate sleeve 18, or a through hole 24 extending in the vertical direction is formed as shown in (B). Further, as shown in (C), it is possible to form the through hole 26 having a shape that extends obliquely,
Further, the present invention can be applied to a vibration-proof rubber bush that does not have the outer tubular metal fitting 14, and the outer tubular metal fitting 14 is divided into two parts in a direction perpendicular to the axis to provide a split type anti-vibration rubber. The present invention can be configured in variously modified forms without departing from the spirit of the present invention such as being applicable to bushes.

[Brief description of drawings]

FIG. 1 is a view showing a vertical cross section and a horizontal cross section of a vibration damping rubber bush according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a shape of an intermediate sleeve of the anti-vibration rubber bush in FIG.

3 is a diagram showing the relationship between the content of reinforcing glass fiber in the intermediate sleeve of FIG. 2, thermal deformation resistance, and adhesiveness.

FIG. 4 is a diagram showing the relationship between temperature and flexural modulus in the intermediate sleeve of FIG. 2 in comparison with an intermediate sleeve made of polyamide resin.

5 is an explanatory view showing a compression test method for the intermediate sleeve of FIG. 2. FIG.

FIG. 6 is a diagram showing results of tests conducted by the method of FIG.

FIG. 7 is a diagram showing another example of the form of the intermediate sleeve of FIG. 2;

[Explanation of symbols]

 10 Anti-Vibration Rubber Bushing 12 Inner Tube Metal Fitting 14 Outer Tube Metal Fitting 16 Rubber Elastic Body 16A Outer Rubber Elastic Body Part 16B Inner Rubber Elastic Body Part 18 Intermediate Sleeve 20, 22, 24, 26 Through Hole

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location // C08K 7/14 C08K 7/14 C08L 71/12 LQN C08L 71/12 LQN B29K 21:00 105 : 24 B29L 31:30

Claims (3)

[Claims] 1. A cylindrical rubber elastic body is fixed to the outer peripheral surface of a rigid inner cylindrical member, and an intermediate sleeve made of PPE resin is embedded and fixed inside the rubber elastic body at an intermediate portion in the thickness direction of the rubber elastic body. Anti-vibration rubber bush characterized by 2. An anti-vibration rubber bush according to claim 1, wherein the intermediate sleeve made of the PPE resin contains reinforced glass fibers in an amount of 5 to 25% by weight based on the PPE base polymer. 3. The method of manufacturing a vibration-proof rubber bush according to claim 1, wherein the rigid inner cylinder member and the intermediate sleeve are set in a cavity of a molding die, and a rubber material is injected into the cavity. At the same time as the rubber elastic body is vulcanized and molded, it is integrated with the rigid inner cylinder member and the intermediate sleeve, and then the molded product is subjected to press-fitting, drawing, etc., to apply a compressive deforming force from the outer peripheral surface side in the radial direction. A method for manufacturing an anti-vibration rubber bush, characterized in that the rubber elastic bodies on the outer peripheral side and the inner peripheral side of the intermediate sleeve are precompressed.