JP2680273B2 - Connection device between steel pipe for piping and hose - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connecting device capable of directly connecting all kinds of hoses from a high pressure hose to a medium and low pressure hose and a steel pipe for piping having an uneven outer diameter.

[0002]

2. Description of the Related Art Generally, in a hydraulic pipe such as a construction machine, an injection molding machine, a hydraulic press, or a pneumatic pipe in various pneumatic equipments, a steel pipe for piping and a hose are connected. However, in such a case, in order to ensure the airtightness of the above-mentioned connecting portion, it is necessary to form a sheet surface at each of the pipe end portions connected to each other and bring the sheet surfaces into close contact with each other.

However, it has been extremely difficult to form a seat surface directly on the pipe end of a long steel pipe for piping and to machine a connecting screw on the outer peripheral portion thereof. That is, when cutting the sheet surface at the pipe end, it is necessary to fix the bite and rotate the long pipe steel pipe that is the work piece, but the circularity of the outer diameter of the steel pipe is poor. As a result, vibration occurs and chattering occurs, and it is almost impossible to form a smooth and highly accurate sheet surface. In addition, it is necessary to machine a connecting screw at the pipe end, but the poor circularity of the outer diameter of the steel pipe for piping causes a problem that the center of the seat surface and the center of the connecting screw are deviated.

Therefore, when connecting a steel pipe for piping and a hose, a special adapter is conventionally attached to one end of the steel pipe for piping.

That is, FIG. 5 is a view showing an example of the connection between a conventional steel pipe for piping and a hose, in which a pipe taper male screw 1a is formed at the pipe end of the pipe steel pipe 1, and the pipe taper male screw 1a is formed. The adapter 2 is screwed onto the screw 1a portion. At the other end of the adapter 2 is a seat surface 2 for connecting with a hose.
a is formed, and parallel threads 2 for pipes are provided on the outer circumference of the other end.
b is formed. In addition, the steel pipe for piping 1 and the adapter 2
Other methods, such as welding, may be used for the connection.

On the other hand, a connector 4 having a seat surface 4a engaging with the seat surface 2a of the adapter 2 is fixedly attached to the end of the hose 3 for connecting to the steel pipe 1 for piping. . The connecting tool 4 has a groove 4b extending in the circumferential direction.
Is formed, and the base end portion of the union nut 5 externally fitted to the connecting tool 4 is engaged with the concave groove 4b, and the union nut 5 is mounted so as to be rotatable only with respect to the connecting tool 4. I am doing it.

When the hose 3 is connected to the steel pipe 1 for piping, the seat surface 4a of the connector 4 is brought into contact with the seat surface 2a of the adapter 2 and the union nut 5 is attached to the parallel pipe thread 2b of the adapter 2. By screwing into the sheet surfaces 4a and 2a, the steel pipes 1 for piping and the hose 3 can be connected together.

[0008]

However, in such a case, it is necessary to always use the adapter for connecting the steel pipe for piping and the hose, and not only for the seat surface of the adapter and the connector, but also for the adapter and the pipe. There is a problem that the airtightness must be ensured also in the connection portion of the steel pipe.

In view of the above points, the present invention has an object to obtain a connecting device in which the above-mentioned adapter is omitted and the steel pipe for piping and the hose can be directly connected.

[0010]

According to the present invention, a male thread for connection is formed by rolling on the outer circumference of a thick portion formed by drawing at the pipe end of a steel pipe for piping, and the drawn portion is formed. Chuck and process the sheet surface on the pipe end of the steel pipe for piping, press the sheet surface of the tip of the connector attached to one end of the hose to the sheet surface, and attach the union nut attached to the connector. It is characterized in that it is screwed to the male screw for coupling.

[0011]

[Operation] The seat surface formed at the tip of the connector is pressed against the seat surface provided at the pipe end of the steel pipe for piping, and the union nut is screwed onto the male screw for connection formed at the pipe end by rolling. By doing so, the hose can be directly connected to the steel pipe for piping. Therefore, the conventional adapter is not required, and the seal portion is also provided in one place, so that the concern about airtightness can be reduced.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings. In the figure, the same parts as those in FIG. 5 are designated by the same reference numerals, and detailed description thereof will be omitted.

In FIG. 1, reference numeral 1 is a steel pipe for piping, and a thick portion necessary for forming a sheet surface is formed at the end of the pipe by drawing. That is, FIG. 2 is a partial cross-sectional side view of the piping steel pipe 1 before drawing, and the pipe end is drawn over a predetermined length range as shown in FIG. A rolled steel screw having a predetermined diameter R (effective diameter) is made on a commercially available steel pipe for piping having an uneven outer diameter, and then the seat surface 10 inclined so as to be reduced inward is formed on the pipe end surface. Form.
Therefore, the male thread 11 for coupling is formed on the outer peripheral portion of the drawn portion by rolling. FIG. 4 shows a partial cross section of the steel pipe for piping after the thread rolling.

When connecting the hose 3 to the steel pipe 1 for piping thus formed, as shown in FIG. 1, the hose 3 is formed at the tip of the connector 4 fixed to the end of the hose 3. The frusto-conical seat surface 4a which is formed is the steel pipe 1 for piping described above.
By engaging with the seat surface 10 formed at the pipe end of the pipe, and screwing the union nut 5 mounted on the connector 4 into the male thread 11 for coupling by rolling the steel pipe 1 for piping. Then, the sheet surfaces 4a and 10 are brought into close contact with each other, and the steel pipe 1 for piping and the hose 3 are connected.

By the way, when a seat surface is formed directly on the pipe end of a steel pipe for piping and a screw is machined on the outer peripheral surface, the pipe surface has a wall thickness necessary for forming the seat surface and the male screw. It is necessary to select a steel pipe, but in this case,
Except for the sheet surface, the wall thickness is unnecessarily thick and excessive, which is disadvantageous in terms of cost and weight.

On the other hand, according to the present invention, as described above, the drawn portion is provided at the end of the pipe, and the male thread for connection is provided by rolling on the outer peripheral surface thereof. Enough parts can be secured. In addition, by performing drawing, the outer diameter is not uniform due to the large tolerance in the standard, and on top of that, the steel pipe for piping with a poor outer roundness has a constant outer diameter and good roundness. When the outer diameter part of the can be formed and the drawn part is chucked and processed to prevent chattering and to form a good sheet surface, at the same time forming a male thread for coupling by rolling. The seat surface center and the joining rolling screw center can be formed without being deformed due to the characteristics of the rolling process, and when joined to the hose, the airtightness of the seat surface can be reliably maintained.

[0017]

According to the present invention, the steel pipe for piping and the hose can be directly connected by the above-mentioned constitution, the conventional adapter can be omitted, and the airtightness can be improved and the cost can be reduced. Further, by bending the steel pipe for piping at a target angle and radius, the direction and angle of the hose connected to the steel pipe for piping can be freely selected.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of a connecting device between a steel pipe for piping and a hose according to the present invention.

FIG. 2 is a partial cross-sectional view of a steel pipe for piping before drawing.

FIG. 3 is a partial cross-sectional view of a steel pipe for piping after drawing.

FIG. 4 is a partial cross-sectional view of a steel pipe for piping after thread rolling.

FIG. 5 is a partial cross-sectional view showing a conventional connecting device.

[Explanation of symbols]

 1 Steel Pipe 2 Piping 2 Adapter 2a Seat Surface 3 Hose 4 Connector 5 Union Nut 10 Seat Surface 11 Male Thread for Coupling

Claims (1)

(57) [Claims] 1. A male thread for connection is formed by rolling on the outer periphery of a thick portion formed by drawing at the pipe end of a steel pipe for piping, and the drawn portion is chucked and arranged as described above.
The sheet surface is processed on the pipe end of the steel pipe for pipes, and the sheet surface is
The sheet surface of the tip of the connector attached to one end of the hose is pressure-welded, and the union nut attached to the connector is screwed to the male thread for coupling, the steel pipe for piping and the hose Connection device.