JPH021587Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Purpose of the Invention] (Industrial Application Field) The present invention relates to a pipe joint structure, and particularly to one used in refrigerant piping of an automobile air conditioner.

(Prior art) For example, in addition to the refrigerant piping that makes up the cooling cycle system, an automotive air conditioner is provided with hot water piping, etc., which guides refrigerant or hot water such as engine cooling water to a heat exchanger, and It is well known that the vehicle interior is heated and cooled by cooling and heating.

In order to connect these pipes and assemble them into a predetermined cooling cycle system, the pipes are connected to each other using joints.
The joint disclosed in Publication No. 174214 is widely used. As shown in FIG. 7, this joint 1 includes a bead portion 2 formed at the tip of a first pipe _P1 , a nut 3 provided so as to abut on the rear end surface 2a of this bead portion 2, and a bead portion 2 formed at the tip of a first pipe P1. 2 An enlarged diameter part 5 is formed at the end of the pipe P ₂ to hold an O-ring 4 fitted to the end base of the bead part 2, and an inner end surface 6 is in contact with the enlarged diameter part 5. 7 and pressurize the O-ring 4 to seal both pipes.
P ₁ and P ₂ are connected.

However, as shown in FIG. 7, if the position of the threaded part between the nut 3 and the union 7 is formed to be large with respect to the radial direction of the pipe P, the outer diameters of the nut 3 and the union 7 will naturally also become large. This not only makes it difficult to penetrate the grommet G of the through hole in the dash panel of the car body, but also
The sealing performance of the pipe by the grommet G also deteriorates.

That is, by making the outer diameter of the pipe P and the outer diameters of the nut 3 and the union 7 as equal as possible, it becomes easier to pass the nut 3 and the pipe P through the grommet G of the dash panel, and it is also possible to pass the nut 3 through the grommet G of the dash panel. Afterwards, the outer peripheral surface of the pipe P can be reliably sealed by the grommet G.

(Problem to be solved by the invention) Here, in the above-mentioned joint, when the nut 3 and the union 7 are tightened excessively or when the tightening is repeated, the enlarged diameter portion 5
The tip 5a may be damaged.

In addition, when attaching and detaching this type of pipe fitting, use two standard spanners, and use one spanner to
It is difficult to control the tightening torque value because the pipes are connected by rotating the nut 3 with the other wrench after fixing the pipe.

In particular, if this tightening becomes excessive, the joint 1 is constructed so that the diameter of the threaded portion between the nut 3 and the union 7 is reduced as much as possible in consideration of the grommet penetrating workability and sealing performance. As shown in Figure 6, the tip 8 of the inner end surface 6 of the union 7 is connected to the pipe P ₂
The tip portion 5a of the enlarged diameter portion 5 is deformed to make it thinner, and the excess thickness is pushed upward in the figure.

When this happens, even if you try to move the nut 3 to the right in the figure in order to uncouple the pipe joint 1, the tip 5a of the enlarged diameter portion 5 will be removed from the position of the female thread tip 9 of the nut 3. is larger by h in the figure, and there is a possibility that this nut 3 cannot be removed.

To prevent this, the tip 5 of the enlarged diameter portion 5
It is possible to reduce the height of the portion a, but since this portion is originally extremely small, measuring approximately 0.5 mm to 1 mm, such processing is also difficult.

Furthermore, the distance l between the inner end surface 5d of this enlarged diameter portion 5 and the outer circumferential surface 10a of the tip portion 10 of the first pipe _P1 is determined by the compression ratio of the O-ring 4 (normally 25 of the O-ring diameter).
%), it is strictly regulated, and inward deformation of the enlarged diameter portion 5 is also not allowed.

For this reason, the work of tightening the nut 3 and the union 7 requires careful attention, and the work is particularly difficult in a narrow place such as an engine room.

This invention focuses on the above-mentioned drawbacks of the conventional method, and was developed in order to improve this.It is a pipe that does not cause the situation where the nut cannot be removed even though the tightening work is performed using the same method as the conventional method. The purpose is to provide a joint structure.

[Structure of the invention] (Means for solving the problem) The present invention to achieve the above object forms a bead on the outer periphery of the tip of one pipe to be connected, and a bead on the end of the other pipe. By forming an enlarged diameter section and holding a sealing member such as an O-ring between the inner end surface of the enlarged diameter section, the outer circumferential surface of the tip, and the front end surface of the bead section, the sealing member can be attached to the pipe. A union whose inner end surface is engaged with the enlarged diameter portion by pressing in the radial direction of the pipe and a nut whose inner end surface is engaged with the bead portion are pressed in the radial direction of the pipe. In a pipe joint that connects both pipes by bringing the tip of the enlarged diameter part into contact with the bead by screwing and tightening the tip at a position close to the tip, the tip of the enlarged diameter part A pipe joint structure in which a vertical piece is formed to stand substantially upright with respect to the base of the tip, and a curved recess is formed on the inner peripheral edge of the tip of the union so that the vertical piece deforms along the bead. It is.

(Function) In the present invention constructed as described above, when the nut and the union are screwed together and lightly tightened, the pipe stops when the tip of the pipe comes into contact with the bead. At this time, a space is created between the curved concave portion of the union and the tip of the enlarged diameter portion.

When further tightened from this state, the tip of the enlarged diameter portion is pressurized by the tip of the union, tilts around the base, and begins to deform along the bead. In particular, since a curved recess is formed at the tip of the union, the tip is compressed between the inner peripheral surface of the curved recess and the bead, and is deformed along the outer peripheral surface of the bead. I will do it.

At this point, the tightening torque becomes considerably large, so
The operator can see that the bolt has been tightened to the specified position, but if the worker tightens it further, the tip of the enlarged diameter section between the curved recess and the bead will be squeezed by the inner peripheral surface of the curved recess and the bead. However, in this case, the excess wall does not try to extend outward in the radial direction of the pipe, but is pressurized by the inner circumferential surface of the curved recess, so it stretches along the outer circumferential surface of the bead. It begins to deform.

Therefore, the tip of this enlarged diameter portion is directed downward by this curved recess, and does not rise above a predetermined height, and the more it is tightened, the more it is oriented along the outer circumferential surface of the bead. It will transform.

Therefore, a gap is created between the tip of the enlarged diameter portion and the tip of the female thread, and the excess wall of the pipe does not get in the way when loosening and removing the nut.

Furthermore, since the pressure is applied in the curved recess when performing this tightening, the tightening force is unlikely to exceed a predetermined value, and there is no risk that the tip of the enlarged diameter portion will be cut by the bead and the tip of the union.

(Embodiment) Next, an embodiment of the present invention will be described with reference to FIGS. 1 to 4. Parts common to those in FIGS. 5 and 6 are denoted by the same reference numerals, and their explanation will be omitted.

The joint pipe 20 according to the present invention shown in FIG.
As shown in FIG. 2, a curved recess 21 having a radius of curvature comparable to the shape of the tip of the bead portion 2 is formed on the inner peripheral edge of the tip 7a of the union 7. Further, as shown in FIG. 2, the distal end 5a of the enlarged diameter section 5 of the pipe _P2 has an upright piece 5c that stands upright from the base 5b, and in particular, the distal end 5a of the enlarged diameter section 5 of the pipe P2 has an upright piece 5c that stands upright from the base 5b. A space 22 is created between them.

The tightening action of the joint 20 configured in this way will be explained.

First, when the nut 3 and the union 7 are screwed together and lightly tightened, the pipe P2 stops when the tip _5a abuts the bead 2, as shown in FIG.

At this time, a space 22 is created between the curved recess 21 of the union 7 and the tip 5a of the enlarged diameter portion 5.

When further tightened from this state, the vertical piece 5c
is pressed against the tip 7a of the union 7, and the base 5
It tilts around b and begins to deform along the bead portion 2 as shown in FIG. In particular, since the curved recess 21 is formed at the tip of the union 7, the tip 5a is pinched between the inner circumferential surface of the curved recess 21 and the bead 2. It will deform along the outer circumferential surface.

At this point, the tightening torque becomes considerably large, so
The operator can see that the bolt has been tightened to the specified position, but if the worker tightens it further, the curved recess 2 will appear as shown in Figure 4.
The vertical piece 5c between the bead portion 2 and the curved recess 21 is gradually thinned and stretched due to the pressure between the inner circumferential surface of the curved recess 21 and the bead portion 2. It does not try to stretch, but is pressurized by the inner circumferential surface of the curved recess 21, so that it deforms along the outer circumferential surface of the bead portion 2.

Therefore, the tip of this upright piece 5c is directed downward by this curved recess 21, and does not rise above a predetermined height, and the more it is tightened, the more it moves along the outer peripheral surface of the bead 2. It will become deformed.

For this reason, a gap _h1 is created between the tip of the vertical piece 5c and the tip 9 of the female thread, and even when the nut 3 is loosened and removed, the excess wall of the pipe _P2 mentioned above does not get in the way.

Moreover, since the pressure is applied by the curved recess 21 when performing this tightening, the tightening force is unlikely to exceed a predetermined value, and there is no possibility that the vertical piece 5c will be cut by the bead portion 2 and the tip of the union 7.

In the above-described embodiment, the curved recess 21 is configured to have a radius of curvature that is almost the same as the outer peripheral shape of the bead, but this radius of curvature should be determined as appropriate by considering the material or wall thickness of the pipe. Bye.

[Effect of the invention] As described above, according to the invention, a curved concave portion is formed on the inner peripheral edge of the tip of the union so that the tip of the expanded diameter portion deforms along the bead portion, so that the surplus when tightening the pipe is reduced. The meat will not get in the way when removing the nut, and even if the tightening torque is increased, this force will push against the curved surface, so the force will be dispersed and will not crush the pipe itself. This provides an excellent effect in that the tightening force is unlikely to exceed a predetermined value.

[Brief explanation of drawings]

Figure 1 is a half-sectional side view of a pipe joint structure according to the present invention, Figures 2, 3, and 4 are sectional views of main parts showing the progress of tightening work, and Figures 5 and 7 are conventional joint structures. A half-section side view showing a half section, No. 6
The figure is an enlarged sectional view of the main part of FIG. 5. 2... Bead portion, 2b... Front end surface, 3... Nut, 3a... Inner end surface, 4... O-ring, 5... Expanded diameter portion, 5a... Tip portion, 5b... Base, 5c...
Vertical piece, 5d... Inner end surface, 6... Inner end surface of union, 7... Union, 7a... Tip, 10...
Tip of one pipe, 20... Fitting, 21...
Curved recess, P ₁ ... one pipe, P ₂ ... other pipe.

Claims (1)

[Claims for Utility Model Registration] A bead portion 2 is formed on the outer periphery of the tip portion 10 of one pipe P1 to be connected, and an enlarged diameter portion 5 is formed on the end of the other pipe P2, and this enlarged diameter portion 5 By holding a sealing member 4 such as an O-ring between the inner end surface 5d of the pipe P1, P2, the outer circumferential surface 10a of the distal end portion 10, and the front end surface 2b of the bead portion 2, the sealing member 4 is secured between the pipes P1 and P2. Press radially,
A union 7 whose inner end surface 6 is engaged with the enlarged diameter portion 5
and a nut 3 whose inner end surface 3a is engaged with the bead portion 2 at a position close to the tip 5a of the enlarged diameter portion 5 in the radial direction of the pipes P1 and P2 and tightened. Accordingly, in a pipe joint in which both pipes P1 and P2 are connected by bringing the tip end 5a of the enlarged diameter portion 5 into contact with the bead portion 2, the tip portion 5a of the enlarged diameter portion 5 is brought into contact with the bead portion 2. A vertical piece 5c is formed that stands almost upright with respect to the base 5b of the union 7, and a curved recess 21 is formed on the inner peripheral edge of the tip 7a of the union 7 so that the vertical piece 5c deforms along the bead 2. A pipe joint structure featuring: