JPS6344540B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method of manufacturing a flexible sleeve for a fluid pressure device.

[Prior Art] Flexible sleeves for fluid pressure devices are widely used as flexible sleeves for air springs, shock absorbers, and the like.

Due to its nature, this flexible sleeve for a fluid pressure device is required to have excellent bending life characteristics. It is difficult to obtain the flex life characteristics of a flexible sleeve for a fluid pressure device from the rubber layer alone, and the flex life characteristics are greatly influenced by the rubber topping blind weave cords embedded inside. Therefore, it is necessary that the rubber topping blind weave cord is not disturbed and is strongly adhered to the rubber layer.

However, in the conventional manufacturing method of a flexible sleeve for a fluid pressure device, the disorder of the rubber topping blind weave cord and the adhesion to the rubber layer were not sufficient.

This is because, as described below, the flexible sleeve for fluid pressure equipment has a small diameter at one end and a large diameter at the other end, which causes the rubber topping blind weave cord to become disordered during the tube expansion process, resulting in uneven thickness. This is because pipe expansion work is unavoidable and degassing cannot be done effectively.

That is, in the conventional manufacturing method of a flexible sleeve for a pressure device, as shown in FIG.
It was manufactured through a preforming process 6, a tube expansion process 9, a vulcanization process 7, and a post process 8.

Among these, the pre-process 5 is various setup processes.
In the next preforming step 6, as shown in FIG. 2, the inner rubber sheet 2 is wound around a roll-shaped winding jig 1 whose outer diameter is equal in the length direction, and then the first rubber topping blind weave cord 3 is placed on the upper layer. Wrap the second rubber-topped blind weave cord 3 around the top layer of the first rubber-topped blind weave cord 3.
In this step, the three layers of the first rubber topping blind weave cord are wound one after another in opposite directions, and the outer rubber sheet 4 is further wound thereon to form a preformed cylindrical body.

The inner rubber sheet 2 and the outer rubber sheet 4 used here are made of soft unvulcanized rubber that exhibits excellent bending life characteristics, and the first rubber topping blind weave cord 3 and the second rubber topping blind weave cord 3 They are topped with a soft unvulcanized rubber sheet that exhibits excellent bending life characteristics, so they will stick just by wrapping them and will not come apart, but it is important to take appropriate measures to prevent fraying. Appropriate.

After the preforming step 6 is completed, the winding jig 1 is removed.

The next tube expansion step 9 is a step in which the preformed cylindrical body is expanded so that one end has a small diameter and the other end has a large diameter by an inner bag method or a mechanical method. The inner bag method is a method in which a rubber tube that expands into a shape to be expanded is placed in a preformed cylindrical body, and then air is sealed in the rubber tube to expand the formed cylindrical body.

In the next vulcanization step 7, the expanded preformed cylindrical body is placed over the core metal of the vulcanization mold, a lid mold is placed over it, and vulcanization is performed.

The final post-process 8 is a step of removing the core metal and the lid mold.

However, in the tube expansion step 9, a preformed cylindrical body having equal inner and outer diameters in the longitudinal direction is expanded so that one end has a small diameter and the other end has a large diameter, while eliminating the disorder of the rubber topping blind weave cord 3. It is extremely difficult to expand the entire tube to a uniform thickness, and it is also impossible to evacuate the air trapped between the layers during preforming, resulting in a large amount of air trapped between the layers of the cylindrical body. Bubbles were generated, which caused a significant decrease in the flex life characteristics.

[Problems to be Solved by the Invention] The present invention has been made based on the above points, and its purpose is to eliminate the drawbacks of the prior art described above, and to create A fluid pressure device capable of expanding a preformed cylindrical body having a diameter to a uniform thickness such that one end has a small diameter and the other end has a large diameter without disturbing the rubber topping blind weave cord and enclosing it without air. An object of the present invention is to provide a method for manufacturing a flexible sleeve for

[Means for Solving the Problems] The gist of the present invention is to subject a preformed cylindrical body after the tube expansion step and before the vulcanization step to peripheral pressure heat treatment in a temperature range in which vulcanization does not progress. A method of manufacturing a flexible sleeve for a fluid pressure device is provided.

That is, the method of manufacturing a flexible sleeve for a fluid pressure device of the present invention involves winding an inner rubber sheet around a roll-shaped winding jig, then winding a first intermediate first rubber topping blind weave cord on the inner rubber sheet layer, and then A second intermediate rubber topping blind weave cord is wound around the first intermediate rubber topping blind weave cord in the opposite direction to the first intermediate rubber topping blind weave cord, and an outer rubber sheet is further wrapped around the upper layer of the second intermediate rubber topping blind weave cord layer. A preformed cylindrical body is obtained by winding the preformed cylindrical body, and this preformed cylindrical body is subjected to pressure heat treatment on the outer circumference in a temperature range where vulcanization does not progress. The present invention provides a method for manufacturing a flexible sleeve for a fluid pressure device in which the pipe is expanded so that the end side has a large diameter and is then vulcanized.

[Function] The method of manufacturing a flexible sleeve for a fluid pressure device of the present invention includes heat-treating a preformed cylindrical body under pressure at its outer periphery in a temperature range in which vulcanization does not progress, thereby forming an inner rubber sheet, a first intermediate rubber topping, and a first intermediate rubber topping. The air trapped between each layer of the blind weave cord, the second intermediate rubber topping blind weave cord, and the outer rubber sheet is degassed under high temperature and pressure, and these layers are adhesively bonded. The preformed cylindrical body is expanded so that one end has a small diameter and the other end has a large diameter so that the first intermediate rubber topping blind weave cord and the second intermediate rubber topping blind weave cord are not disturbed, and then vulcanization is performed. As a result, we have created a flexible sleeve for fluid pressure equipment that has a uniform thickness without any disturbance or internal air bubbles in the rubber topping blind weave cord, and as a result, these elements work synergistically to create a flexible sleeve for fluid pressure equipment that has excellent bending life characteristics. It is something that can be done.

[Example] Next, an example of the method for manufacturing a flexible sleeve for a fluid pressure device according to the present invention will be described with reference to the drawings.

FIG. 3 is a block diagram showing one embodiment of the method of manufacturing a flexible sleeve for a fluid pressure device according to the present invention.

As can be seen from FIG. 3, the present invention includes pre-process 5,
In the method for manufacturing a flexible sleeve for a fluid pressure device manufactured through a preforming process 6, a tube expansion process 9, a vulcanization process 7, and a post process 8, an external pressing process 10 is performed between the preforming process 6 and the tube expansion process 9. It is characterized by the inclusion of

In the present invention, the method for applying pressure to the outer periphery of the external pressing step 10 is a method in which a preformed cylindrical body having equal inner and outer diameters in the length direction is heated while being mechanically compressed from the outer periphery. There are methods such as heating and pressurizing while heating. The temperature of external pressing is preferably a temperature at which the preformed cylindrical body softens and vulcanization does not progress, for example, 50 to 120°C. Also,
The appropriate time for external pressing is 5 to 60 minutes.

The rubber topping blind weave cord 3 of the flexible sleeve for a fluid pressure device obtained by vulcanization firmly adhered to the inner rubber 2 and outer rubber 4, and the adhesive strength was improved by 18% compared to the conventional method. In addition, the bending life characteristics have also been greatly improved.

[Effects of the Invention] According to the method of manufacturing a flexible sleeve for a fluid pressure device of the present invention, trapped air remaining between the layers of a preformed cylindrical body is effectively degassed, and the layers are bonded together. Since the pipe is joined, the pipe is expanded uniformly in the pipe expansion step 9, and the pipe is vulcanized in that state, the thickness is uniform and no air bubbles are generated.
As a result, a flexible sleeve for a fluid pressure device with excellent bending life characteristics can be obtained, which is industrially useful.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a conventional method for manufacturing a flexible sleeve for a fluid pressure device, FIG. 2 is an explanatory diagram of parts in the preliminary process of FIG. 1, and FIG. FIG. 3 is a block diagram showing a method for manufacturing the sleeve. 1... Winding jig, 2... Inner surface rubber, 3... Rubber topping blind weave cord, 4... Outer surface rubber, 5... Pre-process, 6... Preforming process, 7... Vulcanization process, 8... Post-process, 9... Tube expansion process, 10...External pressure.

Claims (1)

[Claims] 1. Wrap an inner rubber sheet around a rolled winding jig, wrap a first intermediate rubber topping blind weave cord on the inner rubber sheet layer, and attach the first intermediate rubber topping blind weave cord to the upper layer of the first intermediate rubber topping blind weave cord layer. A second intermediate rubber topping blind weave cord is wound in the opposite direction to the woven cord, and an outer rubber sheet is wound around the upper layer of the second intermediate rubber topping blind weave cord layer to form a preformed cylindrical body, and the preformed cylindrical body is obtained. In the method for manufacturing a flexible sleeve for a fluid pressure device, the sleeve is expanded so that one end has a small diameter and the other end has a large diameter, and is then vulcanized. A method for manufacturing a flexible sleeve for a fluid pressure device, characterized in that a cylindrical body is subjected to peripheral pressure heat treatment in a temperature range in which vulcanization does not progress.