JPH0562272B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method and apparatus for manufacturing an endless packing, and more particularly to a method and apparatus for manufacturing an endless packing whose end surfaces are parallel to each other.

(Prior art) As a means of highly efficient manufacturing of an endless packing made of a rubber-like elastic material, etc., a cylindrical material having a planar shape equivalent to that of the endless packing is molded,
A method is known in which the cylindrical material is extrapolated or wrapped around a rotating shaft to impart rotational motion, and then cut with a cutting tool to obtain a product.

The one shown in FIG. 5 is an example of a manufacturing method of this type of endless packing that has been conventionally used.
A cylindrical material 5 formed to have the same planar shape as the endless packing is extrapolated onto the rotating shaft 1 arranged at a pitch equal to the width dimension of the endless packing to be manufactured, and while the rotating shaft 1 is rotating. Then, the cutting tool 7 is sent inward in the radial direction, and the endless packing is manufactured by completely cutting it off.

When the endless packing is long, a method is used in which two rotating shafts are arranged approximately in parallel, a cylindrical material is wound around both shafts, and one of the rotating shafts is driven to cut the endless packing using a cutting tool. It is being

(Problems to be Solved by the Invention) In the method for manufacturing an endless packing according to the above-mentioned prior art, as the cutting progresses, the cutting tool 7 supported on one side by the cylindrical material 5 cuts away the endless packing to be cut. Since the packing piece is pushed in the axial direction and causes lateral displacement, the sealing performance of the endless packing is significantly reduced due to problems such as the cut surface not being formed into an accurate plane, especially on the inner circumferential side, and variations in width dimension. Then a problem arises.

One of the inventors, in order to solve the above-mentioned problem at the end point of cutting, as shown in FIG. One of the objectives was achieved by devising a manufacturing method in which they are removed from the rotating shaft in a state in which they are connected to each other due to their thin inner walls, and then separated by hand (see Japanese Patent Laid-Open No. 183239/1983).

However, in this method, when the inner thin wall portions are separated, a protrusion 9 is attached to one side of the endless packings adjacent to each other as shown in the figure, and a chip 10 is generated on the other side, which deteriorates the sealing performance of the endless packings. A problem has occurred.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide a method and apparatus for manufacturing an endless packing having an accurate rectangular cross-sectional shape.

(Means for Solving the Problems) In view of the problems in the endless packing manufacturing means according to the prior art described above, the present invention provides a method for cutting into a cylindrical material with a cutting tool so that the total thickness of the cylindrical material is completely cut. Then, the endless packing pieces connected to each other by the continuous thin parts are removed from the rotating shaft, and the thin parts are removed from the rotating shaft. Each endless packing is formed by separating the parts.

As a means of making a cut in which completely cut parts and incompletely cut parts are arranged alternately, at least one part of the circumferential surface of the rotating shaft into which the cutting tool is cut is formed to have a smaller radius than other parts. The part of the cylindrical material supported by the small radius circumferential surface is closer to the center of the rotating shaft than the part of the cylindrical material supported by the large radius circumferential surface, or the cam mechanism or crank mechanism is used. This is done by arranging the cutting tool and changing the distance between the cutting tool and the rotating shaft during the rotational movement of the cylindrical material.

(Function) According to the method for producing an endless packing of the present invention, parts where the entire thickness of the cylindrical material is completely cut and parts where the thickness is incompletely cut are formed alternately. For example, the formation of the thin part is limited to a part of the entire length of the endless packing, and its cross-sectional area becomes narrow, but the endless packing to be cut is not separated from the cylindrical material throughout the entire cutting process.

In the endless packing manufacturing apparatus of the present invention, a part of the peripheral surface of the rotating shaft around which the cylindrical material is inserted or wrapped is formed to have a smaller radius than the other part,
The cutting tool whose cutting edge enters the relief groove completely cuts the part of the cylindrical material supported on the large radius circumferential surface of the rotating shaft, and cuts the part of the cylindrical material supported on the small radius circumferential surface of the rotating shaft. The section is cut incompletely leaving a thin wall with sharp edges at both ends.

(Embodiment) In the embodiment shown in FIG. 1, a cylindrical material 5 is wound around two rotating shafts arranged approximately parallel to each other, and cut by a cutting tool 7. As shown on the right side of the drawing, a small radius circumferential surface 3 whose radius dimension gradually decreases and then gradually increases again is formed on the circumferential surface of one rotating shaft 1 driven by means not shown, and the remaining portion has the same radius. It is formed as a large radius circumferential surface 4 of.

In the cylindrical material processed by the manufacturing apparatus shown in FIG. 1, completely cut portions 11 and incompletely cut portions 12 are alternately formed, as shown in FIG. 2.

In the embodiment shown in FIG. 3, small-radius circumferential surfaces 3 made of concave curves are formed at two locations on the circumferential surface of the rotating shaft 1, and the other portions are left as large-radius circumferential surfaces 4.

In the embodiment shown in FIG. 4, a small-radius circumferential surface 3 and a large-radius circumferential surface 4 are formed by eccentrically centering the rotation center axis of the rotating shaft 1.

(Effects of the Invention) As described above, the method for producing an endless packing of the present invention alternately forms completely cut parts and incompletely cut parts on a cylindrical material having the same planar shape as the endless packing to be produced. Due to this structure, each endless packing piece is not completely separated from the cylindrical material even at the end of the cutting process, which is different from conventional manufacturing methods in which each endless packing piece is completely separated. In addition, since each endless packing piece is connected to each other only by a thin uncut portion with a narrow cross-sectional area, each endless packing piece is No chips or protrusions were observed during mutual separation.

The endless packing manufacturing apparatus of the present invention has a structure in which a small radius circumferential surface is formed on a part of the circumferential surface of the rotating shaft on which the cylindrical material is inserted or wrapped, so that the large radius circumferential surface can be formed on a large radius circumferential surface. The supported part of the cylindrical material is completely cut, and the part of the cylindrical material supported by the small radius circumferential surface is incompletely cut, so that an alternating arrangement of completely cut parts and incompletely cut parts is created. brought from.

[Brief explanation of the drawing]

FIG. 1 is a plan view and a partial side view of an embodiment of the endless packing manufacturing apparatus of the present invention, and FIG. 2 shows the processing steps of the endless packing manufacturing method of the present invention using the manufacturing apparatus of FIG. 3 and 4 are side views showing other embodiments of the endless packing manufacturing apparatus of the present invention, and FIG. 5 is a side view showing the conventional endless packing manufacturing method and the manufacturing apparatus. FIG. 6 is a cross-sectional view showing a method for manufacturing an endless packing according to the prior art, and a perspective view showing another example of a method for manufacturing an endless packing according to the prior art. 1... Rotating shaft, 2... Relief groove, 3... Small radius circumferential surface, 4... Large radius circumferential surface, 5... Cylindrical material, 7...
Cutting tool, 9...Protrusion, 10...Chip, 11...
Completely cut part, 12... Incompletely cut part.

Claims (1)

[Scope of Claims] 1. Molding a cylindrical material made of rubber-like elastic material, rotating the cylindrical material by hanging it on a rotating shaft, and cutting the cylindrical material in the radial direction with a cutting tool to cut the inner circumferential surface side. A method for producing an endless packing by cutting a part of a chisel along the circumferential direction and connecting the part into a thin wall, and then cutting off the connected part in the thin wall. 2. It has a rotating shaft around which a cylindrical material of rubber-like elastic material is extrapolated or wrapped, the rotating shaft has a circumferential surface having a radius dimension that varies along the circumferential direction, and the rotating shaft has at least the rotational axis with respect to the rotating shaft. Endless packing manufacturing equipment equipped with cutting tools that cut to the maximum circumferential surface of the shaft.