JPH0449436Y2 - - Google Patents

Description

[Detailed explanation of the idea]

(Field of Industrial Application) This invention relates to a fixing structure for a joint fitting in a Freon hose and a nipple fitting as a component thereof. (Prior Art) In a Freon hose, a fitting is fixed to the end of the hose, and the fitting is connected to a mating member through the fitting. This fitting consists of a socket fitting and a nipple fitting having a plurality of annular protrusions formed on the outer circumferential surface, and when the end of the hose body is inserted between them, the socket fitting is inserted in the axial direction. It is fixed to the end of the hose main body by caulking multiple locations toward the axis. By the way, in the case of such Freon hoses, it is necessary to ensure sealing performance at the fitting fixing portion, and various devices have been conventionally used for this purpose. FIG. 7 shows an example. As shown in the figure, in this fixing structure, the nipple fittings 100
Specifically, by forming the annular protrusion 102 on the outer circumferential surface of the annular protrusion 102 into a specific shape, specifically, the cross-sectional shape of the protrusion 102 is formed into a mountain shape having an acute-angled apex, and the socket fitting 104 is shaped like this. By caulking the portion facing the top toward the axis, the compressibility of the end portion 106 of the hose body is locally increased, thereby improving the sealing performance at the fixed portion between the hose body and the fitting. I have to. (Problems to be Solved by the Invention) However, in the case of this fixed structure, if the caulking position of the socket fitting 104 shifts even slightly in the axial direction, the compression ratio for the hose main body end 106 will change significantly. For example, socket fitting 10
If the caulking position of No. 4 shifts to the right or left valley side from the top of the protrusion 102, the compression ratio at the same portion will decrease rapidly. Moreover, the socket metal fitting 104
In practice, it is difficult to accurately control the caulking position, and for this reason, with conventional fixing structures, it is difficult to maintain a constant compression ratio or the axial distribution pattern of the compression ratio at the end of the hose body. Another drawback was that the sealing properties tended to vary from product to product. In addition, in the case of the conventional fixing structure, as shown in FIG.
2 has an acute mountain shape, the tip (top) acts like a knife and cuts the hose body end 1.
There was a problem with the 06 that caused cracks. If such cracks occur, the cracks will progress due to pressure or heat that is repeatedly applied to the hose, and the inner layer of the hose body will eventually break, causing Freon gas leakage and other problems. This may shorten the lifespan. Of course, if the outer circumferential surface of the nipple fitting 100 is made a smooth circumferential surface without forming such a protrusion 102, the above problem will not occur, but in this case, the surface at the fixed part with the hose body Pressure is insufficient. Freon hoses have a caulking ratio (compression ratio) of 20 to 45 to prevent damage to the end of the hose body.
%, and under such caulking ratio conditions, if the outer circumferential surface of the nipple fitting is made to be a smooth circumferential surface, the surface pressure will be insufficient and sufficient sealing performance will not be ensured. (Means for solving the problem) The first solution of the present application relates to a fixing structure of a joint fitting in order to solve such a problem, and its gist is to attach a socket fitting to a protrusion of a nipple fitting. In the fixing structure of a joint fitting for a Freon hose, in which the socket fitting, nipple fitting, and end of the hose body are fixed together by caulking the opposing parts toward the axis, the outer circumferential surface of the protrusion is attached to the axis. a flat surface in the direction, and the length L of the outer peripheral flat surface in the axial direction is 0.3T ₀ to 0.7T ₀ with respect to the wall thickness T ₀ of the end of the hose body;
Moreover, the protrusion height of the protrusions is 0.25L to 0.5L, and the pitch P between the protrusions is L<P≦3T ₀ . In addition, the second solution of the present application relates to a nipple fitting which is a component of such a joint fitting, and its gist is that a plurality of annular protrusions are formed on the outer circumferential surface, and a nipple fitting is formed between the nipple fitting and the socket fitting. A Freon hose nipple fitting that is fixed to the end of the Freon hose body together with the socket fitting by caulking the socket fitting toward the axis while the end of the Freon hose main body is inserted into the Freon hose, The outer circumferential surface of the protrusion is flat in the axial direction, and the length L of the outer circumferential flat surface in the axial direction is 0.3T ₀ to 0.7T with respect to the wall thickness T ₀ of the end of the hose main body. ₀ , the protrusion height of the protrusion is 0.25L to 0.5L, and the pitch P between the protrusions is L<P≦3T ₀ . (Operation and Effects of the Invention) In the present invention, since the outer circumferential surface of the nipple fitting protrusion is a flat surface in the axial direction, even if the caulking position of the socket fitting is slightly shifted in the axial direction, the end of the hose body The compression ratio for This ensures stable sealing performance. However, if the length of the outer peripheral flat surface in the axial direction is short, the displacement of the caulking position of the socket fitting cannot be effectively absorbed. The length of the flat surface is determined by the relationship with the wall thickness of the end of the hose body, and it is preferable to set the length to 0.3T ₀ or more, where T ₀ is the wall thickness of the end of the hose body. It has been confirmed through experiments that the results can be obtained. If the length of the outer peripheral flat surface is longer than necessary, the adhesion between the end of the hose body and the nipple fitting (particularly the adhesion in the groove between the protrusions) will be impaired, and both will be damaged. The frictional resistance between the
Overall, there is a tendency for sealing performance to deteriorate. Therefore, it is necessary to suppress the length of the outer circumferential flat surface of the protrusion to a certain value or less, and it has been confirmed through experiments that the appropriate length is 0.7T ₀ or less. In addition to this, in the present invention, the height H of the protrusions of the nipple fitting and the pitch P between the protrusions are each 0.25L to
It is necessary to set it to 0.5L (L is the length of the flat part of the outer periphery), L<P≦3T ₀ . If the height of the protrusions is lower than 0.25L, the effect of providing such a protrusion will be small, and if it is greater than 0.5L, the groove depth between the protrusions will become deep, and the socket metal When compressing the end of the hose body by caulking, the flesh of the end of the hose body is not fully buried in the groove, and the adhesion between the end of the hose body and the nipple fitting becomes poor.
Overall, there is a tendency for sealing performance to deteriorate. On the other hand, if the pitch P between the protrusions is larger than _3T0 , the frictional resistance between the end of the hose body and the nipple fitting will be low, causing a decrease in sealing performance. (Example) Nipple fittings and socket fittings were fixed to the end of the Freon hose body of the material and structure shown in Table 1 with the structure shown in Figs. 1 to 5, and the heat-resistant sealing test and repeated pressure I conducted a test. In these figures, 10 is a nipple fitting, 12 is a socket fitting, and 14 is a rubber hose body whose end 16 is connected to the nipple fitting 10 and the socket fitting 12.
By inserting the nipple fitting 10, the socket fitting 12, and the hose body end 16 into one body, the socket fitting 12 is inserted between the two and crimped toward the axial center at an appropriate number of locations in the axial direction. has been done. A plurality of annular protrusions 18 are provided on the outer peripheral surface of the nipple fitting 10 at predetermined intervals in the axial direction,
The socket fitting 12 is caulked toward the axis at a portion facing the protrusion 18. The outer peripheral surface of the protrusion 18 of the nipple fitting 10 is a flat surface in the axial direction, as shown in FIG. 6, and the length L of the flat surface 20 in the axial direction is L in FIG. = 0.6T ₀ (T ₀ is the wall thickness of the end of the hose body), L = 0.3T ₀ in Figure 2, L in Figure 3
=0.6T ₀ . In addition, the distance between the protrusions 18, that is, the pitch P is P=
2T ₀ , P=1.0T ₀ in FIG. 2, and P=4T ₀ in FIG. 3. 4 and 5 are the fixing structures shown in FIGS. 1 and 2, respectively, except for the protrusion 18 located at the end of the hose body insertion side.
A groove 22 is provided adjacent to the groove. Table 1 shows the results of a heat-resistant seal test and a repeated pressure test conducted with the nipple fitting 10 and socket fitting 12 fixed to the end 16 of the hose body in each of the above structures. For the heat-resistant seal test, the sample was left in a thermostatic chamber for a specified period of time, then taken out and allowed to cool naturally for 4 to 5 hours.Then, an airtight jig was attached and the sample was submerged in water in the airtight chamber, and a 5 kg
This was done by increasing the pressure every f/cm ² and holding it for 3 minutes to check for leakage pressure. In addition, in the repeated pressure test, the hose was bent with a radius of 100 mm and both ends were fixed.
In this state, oil at a predetermined temperature was circulated inside and pressure was repeatedly applied.

【table】

Claims (1)

[Claims for Utility Model Registration] (1) After inserting the end of the Freon hose body between a socket fitting and a nipple fitting having a plurality of annular protrusions formed on its outer circumferential surface, In a structure for fixing a joint fitting in a Freon hose, the socket fitting, the nipple fitting, and the end of the hose body are fixed together by caulking the part facing the part toward the axis, wherein the outer circumferential surface of the protrusion is a flat surface in the axial direction, and the length L in the axial direction of the outer circumferential flat surface _{is 0.3T 0 to}
0.7T ₀ , and the protrusion height of the protrusion is 0.25L~
0.5L, the pitch P between the protrusions is L<P≦
A fixing structure for a joint fitting in a Freon hose, characterized by a 3T ₀ . (2) A plurality of annular protrusions are formed on the outer circumferential surface, and when the end of the Freon hose body is inserted between the socket fitting and the socket fitting, the socket fitting is caulked toward the axis. A freon hose nipple fitting fixed to the end of the hose body together with a socket fitting, wherein the outer circumferential surface of the protrusion is an axially flat surface, and the axial length of the outer circumferential flat surface is L.
However, with respect to the wall thickness T ₀ of the end of the hose body,
0.3T ₀ to 0.7T ₀ , and the protrusion height of the protrusion is
0.25L to 0.5L, pitch P between protrusions is L<
A nipple fitting for Freon hose characterized by P≦3T ₀ .