JPH0315896Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a pipe joint structure used for interconnecting refrigerant pipes in, for example, an automobile air conditioner.

(Prior art) For example, in an automobile air conditioner, in addition to the refrigerant piping that constitutes the so-called cooling cycle system,
Hot water piping and the like are provided, and the interior of the vehicle is cooled and heated by guiding refrigerant or hot water such as engine cooling water to a heat exchanger, and cooling and heating the air blown into the vehicle interior. The pipe joint structures conventionally used for interconnecting various types of pipes, including the pipes of such automotive air conditioners, are as follows:
As shown in Fig. 6, there is a method for connecting pipes together by threaded engagement. The joint structure shown in Fig. 4 (see Japanese Utility Model Application Publication No. 16082/1982) has an enlarged diameter stepped portion 2 formed on one of the first pipes 1, and a beaded portion 4 formed on the other second pipe 3. The second pipe is inside the first pipe 1.
After inserting the O-ring 5 under pressure until the bead portion 4 of the pipe 3 comes into contact with it, the union 6, which is the first piece, and the second Both pipes 1 and 3 are hermetically connected by threading a nut 7 as a piece.

(Problems to be solved by the invention) However, with this joint structure, when connecting the second pipe 3 to the first pipe 1 as shown in FIG.
When the axes 1a and 3a of both pipes 1 and 3 are tilted, the tip 8 of the first pipe 1 presses the O-ring 5, and the O-ring 5 climbs over the bead 4 of the second pipe 3. There is a risk of it coming off.

Therefore, in order to prevent the O-ring 5 from coming off, a guide member 9 as shown in FIG. If the guide member 9 is inserted into the first pipe 1 with the O-ring 5 fitted into the annular groove 10, the O-ring 5 will be held by the annular groove 10 and removed. Both pipes 1 and 3 can be connected without any problem.

However, this joint structure requires brazing the guide member 9 and the second pipe 3, which makes the joint construction work complicated and disadvantageous in terms of cost.
Since the brazing work is performed, there is a risk that the working environment will deteriorate, and if the wastewater discharged during the brazing work is not treated, there is also a risk of environmental pollution.

The present invention was developed in view of the above-mentioned problems, and aims to provide a pipe joint structure that can prevent O-rings from coming off when pipes are connected, and also eliminates the need for brazing when manufacturing pipe joints. shall be.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a guide ring in which the outer peripheral corner of the end face on the first pipe insertion side is formed into a curved surface in the space in which the O-ring is inserted. and a back-up spring installed so that the O-ring attached to the outer circumferential surface of the second pipe cannot ride on the end surface on the insertion side of the first pipe, and the O-ring is installed between these two rings. This is a characteristic feature.

(Function) According to the means configured in this way, the guide ring guides the pipes when connecting the pipes, so that
This prevents misalignment of the axes and allows the pipe to be inserted smoothly.Moreover, when the pipe is inserted, the O-ring is supported by the end face of the back-up spring, which prevents the O-ring from protruding, and also eliminates the need for brazing when manufacturing the joint. Become.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

FIG. 1 is a reverse sectional view showing an embodiment of the present invention, FIG. 2 is an enlarged sectional view of the main part of FIG.
The same members as the two members shown in the figure are given the same reference numerals, and their explanations will be omitted. This pipe joint 20 includes a guide ring 23 and a back-up spring 24 in a space 22 formed by the enlarged-diameter stepped portion 2 of the first pipe 1 and the cylindrical tip portion 21 of the second pipe 3.
The O-ring 5 is installed between the guide ring 23 and the back-up spring 24.

This guide ring 23 is made of metal and has a substantially rectangular cross section in the axial direction, and the tip end 8 of the first pipe 1 moves in the direction of the arrow from the solid line state shown in FIG. 2 to the two-dot chain line state. When inserting _the first pipe ₁ until This prevents collision with 8.

The insertion side end surface of this guide ring 23
An end surface G ₂ (hereinafter simply referred to as a rear end surface G ₂ ) formed on the opposite side of G 1 is substantially perpendicular to the outer circumferential surface ₂₈ of the distal end portion 21 . And this guide ring 23
The wall thickness tg is smaller than the diameter d (hereinafter simply referred to as diameter d) when the O-ring 5 is in a pressurized natural state, and is about 3/4 d.

On the other hand, the back-up spring 24 is also made of metal and has a substantially rectangular cross section in the axial direction like the guide ring 23, but the insertion side end surface _B1 is erected so that the O-ring 5 cannot ride on it. The surface, for example, is substantially perpendicular to the outer circumferential surface 28 of the tip 21, and the outer circumferential corner corner thereof is chamfered or curved with a small radius of curvature so that it will not be damaged even if the O-ring comes into contact with it.

Also, the rear end surface of this back up spring 24
_B2 The guide ring 23 is formed into a right angle surface or a curved surface along the curved surface of the bead portion 4, similar to the rear end surface _G2 . Note that the wall thickness tb of this back-up spring 24 is also approximately the same as the wall thickness tg of the guide ring 12.

Next, the action will be explained.

With the back-up spring 24, O-ring 5, and guide ring 23 fitted into the tip 21 of the second pipe 3, the first pipe 1 changes from the state shown by the solid line in FIG. 2 to the state shown by the two-dot chain line. When inserted in the direction of the arrow as shown, the tip 8 of the first pipe 1 collides with the insertion side end surface G ₁ of the guide ring 12;
This tip portion 8 is bent into an L-shaped cross section, and the corner portion thereof is formed into a curved surface, so that even if it collides with the curved surface 25 of the guide ring 23, the outer peripheral surface of the guide ring 23 can be smoothly 26 to the right.

Even if the guide ring 23 moves to the right during the collision and pressurizes the O-ring 5, the rear end surface _G2 of the guide ring 23 and the insertion side end surface _B1 of the backup spring 24 will remain parallel to each other. The intersection of the straight line passing through the center of the O-ring and both end surfaces G ₂ and B ₁ (this O-ring 5 and both end surfaces
End faces G ₂ , B ₁ above the contact points P ₁ , P ₂ ) with G ₂ , B ₁
Since O-ring 5 is distracted, both rings 2
3 and 24, the O-ring 5 does not ride on the back-up spring 24.

Then, when the tip 8 of the first pipe 1 starts moving along the outer circumferential surface 26 of the guide ring 23, the O-ring 5 pushes the guide ring 23 back to its original position by its own elasticity. become a state.

Furthermore, when the tip 8 moves to the right, the tip 8 collides with the O-ring 5, but since this collision occurs above the center line of the O-ring 5, the O-ring 5 is rather pushed down by the tip 8. The guide ring 23 and the back-up spring 24 are elastically deformed and contracted so as to expand, resulting in the state shown by the two-dot chain line in FIG.

Therefore, the tip 8 of this first pipe 1 is O
While pressurizing the ring 5, press the back-up spring 24.
It moves to the outer circumferential surface 27 of and comes into contact with the bead portion 4.

At this contact portion, both pipes 1 and 3 are connected by threading the union 6 and the nut 7 together using a conventional method.

However, in the embodiment described above, the guide ring 23 and the back-up spring 24 are simply inserted into the tip end 21 of the second pipe 3, so when the first pipe 1 is pulled out from the second pipe 3, the O-ring 5 There is a risk that they will also escape together. In order to prevent such coming off, for example, the diameter of the second pipe 3 and the tip portion 21 may be expanded, and both rings 23, 24 and the second
The pipe 3 may be fixed by caulking. Note that when performing this caulking fixation, it is necessary to take into account the elastic deformation of the O-ring 5 and set the distance l between both rings 23 and 24 to a predetermined value.

FIG. 3 shows another embodiment of the present invention,
The O-ring 5 is made double to further improve the sealing performance, but in this case, as in the previous embodiment, a curved surface 25 is formed on the insertion side end surface _G1 of the guide ring 23, and the first , each end surface _B1 of the second back-up spring 24 needs to be perpendicular to the outer circumferential surface 28 of the second pipe 3, so that the O-ring 5 can be prevented from riding up.

(Effects of the invention) As described above, according to the invention, a guide ring in which the outer peripheral edge corner of the end face on the first pipe insertion side is formed into a curved surface is provided in the space in which the O-ring is inserted;
A back-up spring is installed so that the O-ring attached to the outer peripheral surface of the second pipe cannot ride on the end surface of the pipe insertion side, and an O-ring is installed between the two rings.
Because the ring is installed, brazing work during joint manufacturing can be eliminated, and O-ring protrusion can be prevented during pipe connection work.

[Brief explanation of the drawing]

FIG. 1 is a half-sectional view showing an embodiment of the present invention;
Figure 2 is an enlarged sectional view of the main part of Figure 1, and Figure 3 is
FIG. 4 is a half-sectional view showing another embodiment of the present invention.
FIG. 5 is a half-sectional view showing a conventional pipe joint structure, FIG. 5 is an explanatory diagram of the same pipe joint structure, and FIG. 6 is a cross-sectional view showing another conventional pipe joint structure. DESCRIPTION OF SYMBOLS 1... First pipe, 2... Expanded diameter step part, 3... Second pipe, 4... Bead part, 5... O-ring, 6
...First piece, 7 ... Second piece, 22 ... Space, 23 ... Guide ring, 24 ... Backup spring, 25 ... Curved portion, B ₁ ... Insertion side end surface,
G ₁ ... end face.

Claims (1)

[Scope of utility model registration request] A first pipe 1 having an enlarged diameter stepped portion 2;
A second pipe 3 is inserted into the pipe 1 until the bead part 4 comes into contact with the second pipe 3, and an O-ring 5 is interposed between the second pipe 3 and the first piece 6, which engages with the enlarged diameter step part 2, and the bead part 4. In the pipe joint structure in which the first and second pipes 1 and 3 are connected in a sealed manner by mutually connecting the second piece 7 that engages with the O-ring 5, , a guide ring 23 whose outer peripheral edge corner of the first pipe insertion side end surface _G1 is formed into a curved surface 25, and an O ring 5 whose first pipe insertion side end surface _B1 is attached to the outer peripheral surface of the second pipe 3. A back-up spring 24 is installed vertically so that the
A pipe joint structure in which the O-ring 5 is installed between 24 and 24.