JPS6023025A - Fixing method of rubber part - Google Patents

Abstract

PURPOSE:To prevent the permanent set of a rubber part and to make the fixing easy by a method wherein the rubber part is cooled and frozen previously under a state that it is stretched to the size and shape easy to fix to a device to be fixed and after it is fixed it is returned to the initial state. CONSTITUTION:A rubber part (for example: a rubber dust boot used for a connector of the cylinder 2, etc.) 1 is stretched to the size or shape easy to fix to the adjuster 3 as a device to be fixed, for example, by fixing to the cylindrical jig 7 having a diameter larger than the outer diameter of the adjuster 3. Then, the part 1 is cooled and frozen under the glass transition temperature of the rubber material composing the part 1 and the frozen part 1 is fixed to the fixing portion 3. Then, the part is heated naturally or forcedly and returned to the normal and then the initial state.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for attaching rubber parts to automobiles, various machines, devices, and the like.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1 and 2, a conventional method for attaching rubber parts will be described. The example shown is a rubber dust boot (1) used at the joint of the cylinder and a cylinder (2).
) and the adjuster (3) to prevent moisture or dust from entering from the outside. The inner diameter of this dust boot (1) is approximately 30 m, and the adjuster (3) has a larger diameter (approximately 50 mm). , is attached to the joint part (4) through the adjuster (3). Specifically, in order to improve the workability of the mounting process, the dust boots (1-inch) are first heated in an atmosphere of about 100°C for about 2 hours before mounting, as shown in Figure 2 (a).(5)
is a heater. The dust boots in this heated state (
1) is stretched by approximately 240% several times using stretching jigs (6) (6). After such pretreatment, dust boots (1
) is attached to the joint part (4) through the adjuster (3) manually by an operator. The dust boot (1) is then angularly extended to pass the adjuster (3).

In this way, in the conventional method, the dust boop (1)
Because it is repeatedly stretched at high or normal temperatures, permanent elongation occurs, which reduces the tightening force, and the function of shielding and protecting the joint from the outside world becomes incomplete. The characteristic shown by curve B in FIGS. 5 and 6 shows permanent deformation according to the conventional example.

OBJECTS OF THE INVENTION An object of the present invention is to provide a new mounting method in which almost no permanent deformation remains in a rubber component upon completion of mounting the rubber component onto a device to be mounted.

Structure of the Invention The present invention involves cooling and freezing a rubber component, which is stretched to a size or shape that is easy to attach to a device to be attached, to a temperature below the glass transition temperature of a rubber polymer constituting the rubber component. The rubber component in the frozen state is mounted on the device to be mounted, and then the rubber component is returned to room temperature to return to its elastic state, thereby elastically tightening it to the mounting position.

In Example 3, a dust boot (with an inner diameter of about 30 mm) is shown.
1) is first stretched and hung on a cylindrical jig (7) having a diameter slightly larger than the outer diameter of the adjuster (3) at room temperature, forming the dust boot (1), as shown in Figure (A). The rubber material is cooled below its glass transition temperature. This cooling brings the dust boot (L) into a frozen state, and the extended state is maintained even when removed from the cylindrical jig (7). Therefore, as shown in Figure (b), the dust boot (1) in a frozen state is placed at the joint part (4) with the cylinder (2) through the adjuster (3) and allowed to warm up naturally at room temperature. If the dust boot (1) is forcibly heated to return to its original elastic state, the dust boot (1) will almost completely return to its original diameter without causing permanent deformation, and sufficient tightening force will be obtained. The reason why the cooling temperature of the dust boot (1) is set to the glass transition temperature of the rubber polymer that makes up the dust boot (1) is that below the glass transition temperature, the molecular motion freezes and becomes a glass state. This is because it is easy to attach and can almost completely return to its original shape and size when returned to room temperature.

Examples of the present invention will be described below using specific experimental examples while comparing them with conventional examples.

Experimental Example 1 An experiment was conducted using an O-ring with a diameter of 25 mm made of ethylene propylene rubber (EP'r) (hardness 60) (manufactured by Sumitomo Chemical Co., Ltd., Nisblen 502 (trade name)). The glass transition temperature of this EPT is about -40°C. This O-ring was placed in a cylindrical jig with a diameter of 5 Qu+ (elongation rate 100%) and cooled for 10 minutes in an atmosphere of -40°C, and then heated at 70°C for 10 minutes. After 10 minutes of this heating treatment had elapsed, the diameter of the O-ring was measured every hour thereafter, and the result A shown in the following table was obtained.

Table 1 Note that measurement result B in Table 1 shows the conventional example, and after 100% elongation at room temperature, 0.00000
The diameter of the ring was measured.

Figure 4 shows these measurement results in a graph.
The vertical axis shows the boot original diameter (xO) and the boot diameter at time t (
The difference ΔX (-Xt-Xo) between Xt) and time t are plotted on the horizontal axis. In the conventional example, as shown in curve B, a deformation of approximately 0.6++n remains even after 3 hours have passed after the elongation was released, which is a ratio of slightly more than 2% to the optical diameter (25.1 mm). ing. On the other hand, in the example, as shown by curve A, it completely returned to its original shape one hour after the heating treatment.

Experimental Example 2 Using natural rubber (NR) (hardness 66) as the test material, an O-ring with a diameter of approximately 25 inches was made as in Experimental Example 1, and 1
The same experiment as above was conducted with 00% elongation.

Note that the glass transition temperature of NR is about -70°C. Table A below shows the measurement results of this example, and Table B shows the measurement results of a conventional example similar to the above, conducted at room temperature.

Table 2 - 70°C in methanol (dry ice cooling) Figure 5 shows these measurement results in a graph. The deformation after returning to the original state is approximately 0.2 mm. This is approximately 0.8% of the original value (25,2+n), which is practically negligible. In contrast, in the conventional example,
As shown in curve B (after heating treatment, a stable state is finally reached after approximately 2 hours have passed, but the deformation at this time is as large as approximately 1.2 fins, which is the same as that of Mototsu (25,0 dragon). 4.8%
This is a considerably large value, and adverse effects in practical use are unavoidable.

Effects of the Invention The method for attaching a rubber component of the present invention is to stretch a 91% rubber product to a size or shape that is easy to attach to a device to be attached, and then cool it to a temperature below the glass transition temperature of the constituent rubber polymer. The molecular motion is stopped, that is, frozen, the frozen rubber part is mounted on a device to be mounted, and then it is returned to its original state by natural or forced heating. Therefore, compared to the conventional work in which an operator uses a jig or manually stretches a rubber part and attaches it to the device to be attached, the attachment work is much easier and requires less effort. becomes. Moreover, according to the present invention, the permanent deformation that remains after the rubber parts are installed can be significantly reduced compared to the conventional example, so that sufficient tightening force can be maintained and the rubber parts can be The original functions of the parts are not impaired. In particular, parts such as the dust boots mentioned as examples,
If permanent deformation occurs, unnecessary substances such as moisture and dust will enter the dust boot, causing a fatal defect in the dust boot, but the present invention can prevent such defects from occurring. In addition, in the embodiments, explanations have been given of cases where the rubber parts, such as a large diameter part, are required to be stretched before reaching the mounting position of the device to be mounted, but such a large diameter part is not necessarily a necessary condition. Of course, the present invention can also be applied to a device having a structure that allows it to be attached to the attachment position with only a slight extension.In this case, the operator does not need to extend the rubber part during the attachment operation. This has the effect of simplifying the work.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a state in which a rubber component is attached to a device to be attached, FIGS. 2(A) and 2(B) are perspective views for explaining a conventional attachment method, and FIG. A), B), and C are perspective views for explaining the embodiment of the present invention, and FIGS. 4 and 5 are curve diagrams showing temporal changes in deformation in the conventional example and the embodiment. (1)...Dust boot (2)...Cylinder (3
)...Adjuster (4)...Joint part (7)...
・Cylindrical jig patent applicant Molten Rubber L Gyo Co., Ltd. Representative Fumiya Tamiaki 1 (Jun 1 No (B) (C) Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] 1. A go that is attached to the attached device and elastically tightens the attachment position! , in the method of attaching a rubber component, the rubber component is stretched to a size or shape that is easy to attach to the device to be attached, and then cooled and frozen to a temperature below the glass transition temperature of the rubber material constituting the rubber component. Then, the rubber part in the frozen state is mounted on the mounting position of the device to be mounted, and then the rubber part is returned to room temperature to return to its elastic state, thereby elastically tightening the mounting position. A method of attaching rubber parts characterized by