JPH0620947Y2 - Pipe fitting device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a pipe joint device, and more particularly to a pipe joint device for a vehicle.

[Conventional technology]

Steel pipes such as air pipes for sending air and oil pipes for sending oil are installed in vehicles, but these steel pipes are not continuous pipes for reasons of vehicle structure, but are connected by pipe joint devices at arbitrary points. It has become a pipe.

In this type of pipe joint device, generally, a flare portion 15 having an enlarged tip end of a steel pipe 14 is brought into contact with a seat surface 13 of the joint body 12 as shown in FIGS. 4 to 6 and screwed into the joint body 12. By tightening the flare nut 16a or 16b, the flare portion 1 is tightened from the rear surface 18 of the flare portion 15.
The steel pipe 14 is connected so that 5 is in close contact with the seat surface 13.

Incidentally, FIG. 4 is a type by tightening a flare nut 16a composed of an external screw, and FIG. 5 is an enlarged view of a main part thereof. FIG. 6 shows a flare nut 16b composed of an inner screw.
It is of the type by.

[Problems to be Solved by the Invention] However, in the pipe joint device, a twisting force is directly applied to the flare portion 15 of the steel pipe 13 when the flare nut 16a or 16b is tightened. Therefore, a crack may occur at the base of the flare portion 15.

Further, when there is a gap between the tightening surface 17 of the flare nut 16a or 16b and the back surface 18 of the flare portion 15 due to a component dimension error or the like, a shearing force due to stress concentration at the root of the flare portion 15 due to vibration or the like. There was a risk that it would work and harden and crack.

By the way, there is a conventional pipe joint in which a flexible or elastic connecting piece is interposed between the flare portion and the joint body (Japanese Utility Model Laid-Open No. 62-73186), and the above problem can be solved to some extent, but the flare nut is tightened. The urging force is directly applied to the flare part and has not been fundamentally resolved.

In addition, a resin tube inserted into the joint body (Shokai Sho 62
-73185), but it could not solve the above problems at all.

The present invention has been made in view of the above, and an object thereof is to provide a pipe joint device capable of preventing cracks in a flare portion caused by a twisting force or a shearing force.

[Means for Solving the Problems]

The configuration of the present invention for achieving the above object is a pipe joint device for connecting steel pipes by press-contacting a flare portion having a diameter of a steel pipe tip expanded by tightening a flare nut to a seat surface of the joint body. The flaring portion and the flaring nut tightening surface should have an inclination angle that is less than a right angle at which the tightening force increases in the axial direction, and the inclination angle should be approximately the same as the inclination angle between the back surface of the flare portion of the steel pipe and the flaring nut tightening surface. That is, a soft member having a substantially rhombic cross section having an angle is interposed.

[Action]

When the flare nut is tightened, the tightening force is indirectly transmitted to the flare portion via the soft member, and the twisting force is weakened.

Also, by tightening the flare nut, the soft member having a substantially rhombic cross section interposed between the flare nut and the flare portion is deformed, the steel pipe and the joint body are brought into close contact with each other, and the gap between them disappears, or the soft member Acts as a cushioning material, and shearing force (stress concentration) on the flare portion due to twisting force and vibration is eliminated.

Furthermore, by setting the angle of inclination of the tightening surface of the flare portion and the flare nut to be more than a right angle at which the tightening force increases in the axial direction, the soft member comes into pressure contact with the flare portion and the gap between the steel pipe and the joint body is increased. The airtightness of is improved.

〔Example〕

 Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an embodiment of a pipe joint device according to the present invention, and FIG. 2 is an enlarged sectional view of a main part thereof.

Reference numeral 1 is a joint body, and a through hole 2 through which air or oil passes is formed in the center of the joint body. A mounting groove 3 is formed at an end of the joint body 1, and an inner screw 4 is formed on an inner wall surface of the mounting groove 3.
And a seat surface 5 having a truncated cone shape is provided at the bottom of the mounting groove 3.

A flare nut 6a is detachably attached to the internal screw 4. 7 is a steel pipe consisting of an air pipe or an oil pipe,
A flared portion 8 having an enlarged diameter is provided at the tip. The flare portion 8 is in contact with the frustoconical seat surface 5 of the joint body 1. Then, between the back surface 9 of the flare portion 8 and the tightening surface 10 of the flare nut 6a, a soft member 11 made of a soft metal sheet such as brass and having a substantially rhombic cross section is interposed, and by tightening the flare nut 6a. The flare portion 8 is brought into pressure contact with the seat surface 5 of the joint body 1 to connect the steel pipe 7.

The flaring portion 8 and the tightening surface 10 of the flare nut 6a have an inclination angle of, for example, about 42 ° or less, which is a right angle at which the tightening force increases in the axial direction, and the soft member 11 also has the same inclination angle as the inclination angle. It has an approximately rhombic cross section with an angle,
Its thickness is about 3 mm.

According to the pipe joint device having such a configuration, the flare nut 6a
The tightening force of the flare nut 6a when tightening the
The flare portion 8 is indirectly transmitted to the flare portion 8 through, and the twisting force is not applied to the flare portion 8.

Therefore, it is possible to prevent the flare portion 8 from cracking due to the twisting force.

Further, the flare nut 6a is tightened by tightening the flare nut 6a.
The soft member 11 having a substantially rhombic cross section interposed between the a and the flare portion 8 is deformed, and the flare portion 8 of the steel pipe 7 and the seat surface 5 of the joint body 1 come into close contact with each other. The gap with 1 disappears.

Of course, since the soft member 11 acts as a cushioning material, twisting force and shearing force (stress concentration) are eliminated.

The flaring portion 8 and the tightening surface 10 of the flare nut 6a have an inclination angle of, for example, about 42 ° or less at a right angle, and the force component increases the tightening force in the axial direction as shown in FIG. Since the force acts, the soft member 11 is brought into pressure contact with the flare portion 8, and the airtightness between the flare portion 8 of the steel pipe 7 and the seat surface 5 of the joint body 1 is ensured.

Therefore, stress is not concentrated on the flare portion 8 even if external vibration is applied, cracks are prevented, and the airtightness between the steel pipe 7 and the joint body 1 is good.

In FIG. 3, the flare nut 6a is an internal thread, and the same effect as in the above embodiment can be obtained.

[Effect of device]

As described above, according to the present invention, the inclination angle of the flared portion of the steel pipe and the tightening surface of the flare nut are specified, and a soft member having a substantially rhombic cross section having substantially the same inclination angle is interposed between them. Thus, the twisting force or the shearing force is not applied to the flare portion, cracks are prevented, and the airtightness between the steel pipe and the joint body is improved.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention, FIG. 2 is an enlarged sectional view of an essential portion of FIG. 1, and FIG. 3 is a sectional view of another embodiment of the present invention, FIGS. 4 and 6. Is a cross-sectional view of each conventionally used pipe coupling device, and FIG. 5 is an enlarged cross-sectional view of a main part of FIG. DESCRIPTION OF SYMBOLS 1 ... Joint main body 5 ... Seat surface 6a, 6b ... Flare nut 7 ... Steel pipe 9 ... Rear surface 10 ... Tightening surface 11 ... Soft member.

Claims (1)

[Scope of utility model registration request] Claim: What is claimed is: 1. A pipe joint device for connecting steel pipes by pressing a flare portion, which is obtained by expanding the diameter of a steel pipe by tightening a flare nut, against the seat surface of the joint body to connect the steel pipes. The angle of inclination of the surface is set to a right angle or less at which the tightening force increases in the axial direction, and the cross-section of a substantially rhombic shape having a tilt angle substantially the same as the tilt angle between the back surface of the flare portion of the steel pipe and the tightening surface of the flare nut. A pipe joint characterized in that a soft member is interposed.