WO2017022608A1

WO2017022608A1 - Pipe joint, pipe connection structure, and air conditioning apparatus

Info

Publication number: WO2017022608A1
Application number: PCT/JP2016/072124
Authority: WO
Inventors: 法文丸山; 晴彦村上; 文則梶野; 茂男吉井; 中田　春男
Original assignee: ダイキン工業株式会社; オーケー器材株式会社
Priority date: 2015-08-04
Filing date: 2016-07-28
Publication date: 2017-02-09
Also published as: JP6012823B1; JP2017032099A

Abstract

A pipe joint (1) is a flareless pipe joint (1) with an external diameter of 19.05 mm to 38.10 mm that is for connecting pipes (2). The pipe joint (1) is provided with: a joint body (10) into which a pipe (2) is inserted; and a front ferrule (21) that has a circular shape for surrounding the circumference of the pipe (2) and has a leading end (21A). In the pipe joint (1), the pipe gap ratio, which is the ratio of the gap (D1) in the radial direction between the joint body (10) and the pipe (2) with respect to the thickness (T1) in the radial direction of the leading end (21A), is 0.3 to 0.8.

Description

Pipe joint, piping connection structure and air conditioner

The present invention relates to a pipe joint, a pipe connection structure including the pipe joint, and an air conditioner.

Conventionally, it is a pipe joint used for a piping system of an air conditioner refrigerator, and is disposed between a joint body into which piping is inserted, a nut fastened to the joint body, and the joint body and the nut. There is known a pipe joint including a front ferrule and a back ferrule. This pipe joint is a bite type pipe joint that secures airtightness and pipe holding force by restraining the outer periphery of the pipe by the front ferrule and the back ferrule and deforming the pipe. Patent Document 1 below describes an example of such a double ferrule-type bite type joint.

The conventional bite type joint has a problem that it is necessary to obtain a desired amount of deformation of the pipe in order to ensure a certain holding force of the pipe, and the tightening torque increases accordingly.

JP 11-325342 A

An object of the present invention is to provide a bite type pipe joint capable of sufficiently securing a deformation amount of a pipe and reducing a tightening torque, a pipe connection structure provided with the same, and an air conditioner. is there.

The pipe joint according to one aspect of the present invention is a bite type pipe joint for connecting pipes having an outer diameter of 19.05 mm or more and 38.10 mm or less. The pipe joint includes a joint body into which the pipe is inserted, and a first ferrule having a ring shape surrounding the circumference of the pipe and having a first tip portion. In the pipe joint, a pipe gap ratio that is a ratio of a gap in the radial direction between the joint body and the pipe to a thickness in the radial direction of the ring shape of the first tip portion is 0.3 or more and 0. .8 or less.

It is the schematic which shows the structure of the air conditioning apparatus which concerns on one Embodiment of this invention. It is the schematic which shows partially the connection structure of piping which concerns on one Embodiment of this invention, and the cross-section of a pipe joint. It is an enlarged view in the area | region III in FIG. It is the schematic which shows a mode that a ferrule tip deform | transforms at the time of nut fastening. It is the schematic which shows a mode that piping deform | transforms at the time of nut fastening. It is the schematic which shows a mode that the front-end | tip of a ferrule warps at the time of nut fastening. It is a graph which shows the relationship between a nut rotation angle and ferrule deformation amount, and the relationship between a nut rotation angle and fastening torque. It is a graph which shows the relationship between the pipe outer diameter and the ratio of the pipe gap to the pipe outer diameter. It is an enlarged view of the ferrule tip part concerning modification 1 of the above-mentioned embodiment. It is an enlarged view of the ferrule tip part concerning modification 2 of the above-mentioned embodiment. It is a graph which shows the relationship between piping clearance ratio and a deformation torque number.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

<Air conditioning device>
First, an air conditioner 100 according to an embodiment of the present invention will be described with reference to FIG. As shown in FIG. 1, the air conditioner 100 is a multi-type air conditioner for buildings, and includes an outdoor unit 101 and a plurality of indoor units 102 connected in parallel to the outdoor unit 101. I have. In addition, the air conditioning apparatus of this invention is not limited to this, The thing of the type by which the one indoor unit 102 was provided with respect to the one outdoor unit 101 may be used.

The outdoor unit 101 mainly includes a compressor 103, a four-way switching valve 104, an outdoor heat exchanger 105, an outdoor expansion valve 106, and a pipe 2 that connects them. Each indoor unit 102 mainly includes an indoor expansion valve 111, an indoor heat exchanger 112, and a pipe 2 connecting them. A gas side closing valve 122 is provided at one end of the pipe 2 of the outdoor unit 101, and a liquid side closing valve 121 is provided at the other end of the pipe 2 of the outdoor unit 101.

During the cooling operation, the four-way switching valve 104 is maintained in a state indicated by a solid line in FIG. The high-temperature and high-pressure gas refrigerant discharged from the compressor 103 flows into the outdoor heat exchanger 105 through the four-way switching valve 104, exchanges heat with outdoor air, and condenses and liquefies. The liquefied refrigerant passes through the open outdoor expansion valve 106 and flows into the indoor units 102 through the pipe 2. In the indoor unit 102, the refrigerant is depressurized to a predetermined low pressure by the indoor expansion valve 111, and further evaporated by exchanging heat with indoor air in the indoor heat exchanger 112. The indoor air cooled by the evaporation of the refrigerant is blown out into the room by an indoor fan (not shown) to cool the room. The refrigerant evaporated and vaporized in the indoor heat exchanger 112 returns to the outdoor unit 101 through the pipe 2 (gas side refrigerant communication pipe) and is sucked into the compressor 103.

On the other hand, during the heating operation, the four-way switching valve 104 is held in a state indicated by a broken line in FIG. The high-temperature and high-pressure gas refrigerant discharged from the compressor 103 flows into the indoor heat exchanger 112 of each indoor unit 102 via the four-way switching valve 104, exchanges heat with indoor air, and condenses and liquefies. The indoor air heated by the condensation of the refrigerant is blown out into the room by an indoor fan to heat the room. The refrigerant liquefied in the indoor heat exchanger 112 returns to the outdoor unit 101 from the open indoor expansion valve 111 through the pipe 2 (liquid side refrigerant communication pipe). The refrigerant that has returned to the outdoor unit 101 is decompressed to a predetermined low pressure by the outdoor expansion valve 106, and further evaporates by exchanging heat with outdoor air in the outdoor heat exchanger 105. Then, the refrigerant evaporated and evaporated in the outdoor heat exchanger 105 is sucked into the compressor 103 through the four-way switching valve 104.

In FIG. 1, the pipe 2 is schematically shown by a solid line, but the air conditioner 100 includes a connection structure in which the pipes 2 are connected using the pipe joint according to the present embodiment. Yes. Hereinafter, the connection structure of the pipe 2 and the structure of the pipe joint 1 for connecting the pipe 2 will be described in detail.

<Piping connection structure and pipe joint structure>
Next, the structure of the pipe joint 1 according to an embodiment of the present invention and the connection structure of a pipe provided with the pipe joint 1 will be described with reference to FIGS. FIG. 2 partially shows a cross-sectional structure of the pipe joint 1 in a state before the nut 30 is fastened. FIG. 3 is an enlarged view of the pipe joint 1 in the region III shown in FIG.

The pipe joint 1 is for connecting the pipes 2 in a refrigerator of an air conditioner, for example. In FIG. 2, only the right side of the connection portion between the pipes 2 of the pipe joint 1 is shown, but the left side also has the same cross-sectional structure, and the pipes 2 are connected via the pipe joint 1.

The pipe joint 1 mainly includes a joint body 10, a front ferrule 21 (first ferrule), a back ferrule 22 (second ferrule), and a nut 30. As shown in FIG. 2, the pipe joint 1 includes a front ferrule 21 interposed between the joint body 10 and the nut 30 by inserting the pipe 2 into the joint body 10 and fastening the nut 30 to the joint body 10. The outer periphery of the pipe 2 is restrained by the tip of the back ferrule 22. And the holding force and airtightness of the piping 2 are ensured by tightening the nut 30 to bite the tip and deforming the piping 2 radially inward.

The pipe 2 has a cylindrical shape in which a hollow portion through which a fluid such as a refrigerant passes is formed. The pipe 2 is, for example, a copper pipe. The pipe 2 has an outer diameter of 19.05 mm or more and 38.10 mm or less. In the pipe 2, the ratio of the radial thickness T0 to the outer diameter (pipe thickness / pipe outer diameter) is in the range of 0.03 to 0.13. The pipe 2 is preferably made of copper that is easily deformed as in the present embodiment, but is not limited thereto, and may be made of aluminum or steel, for example. Further, the pipe 2 is not limited to the one for flowing the refrigerant, but may be one through which other fluid such as water or hot water flows.

As shown in FIG. 2, the pipe connection structure according to the present embodiment includes a pipe 2 having an outer diameter of 19.05 mm or more and 38.10 mm or less, and a pipe joint 1 that connects terminal ends of the pipe 2. Is. According to this pipe connection structure, the pipe 2 is inserted into the joint body 10, the nut 30 is fastened to the joint body 10, and the nut 30 is tightened to bite the front ferrule 21 and the back ferrule 22. By deforming the pipe 2 inward in the radial direction, the holding force and airtightness of the pipe 2 can be ensured.

The joint body 10 is a brass member having a substantially cylindrical shape with a hollow portion formed therein. In the joint body 10, the inner diameter is larger than the outer diameter of the pipe 2, and an insertion hole into which the pipe 2 is inserted is formed on the inner peripheral surface side. The joint main body 10 is connected to the main body surface 12 which is an inner peripheral surface substantially parallel to the axial direction P of the pipe 2 and the main body surface 12 and is inclined with respect to the axial direction P at a first inclination angle θ1. A main body inclined surface 11 which is an inner peripheral surface. The main body inclined surface 11 is inclined radially outward so that the inner diameter is enlarged toward both end portions of the joint main body 10.

The main body surface 12 of the joint main body 10 is formed with a contact portion 13 that protrudes inward in the radial direction and contacts one end of the pipe 2. The contact portion 13 is formed in an annular shape along the body surface 12 of the joint body 10. On the outer peripheral surface of the joint body 10, there is provided a grip portion 14 that is gripped by a general-purpose tool such as a spanner or a wrench when the nut 30 is fastened. The gripping portion 14 has a hexagonal outer shape when viewed from the axial direction P. On the outer peripheral surfaces at both ends of the joint body 10, body thread portions 15 that are fitted to the nut 30 when the nut 30 is fastened are formed.

The nut 30 is a brass member having a ring shape, and is externally fitted to the joint body 10. The nut 30 includes a nut surface 31 that is an inner peripheral surface substantially parallel to the axial direction P of the pipe 2, a nut inclined surface 32 that is connected to the nut surface 31 and is inclined radially inward, and the nut inclination And a nut circumferential surface 34 that is connected to the surface 32 and defines an insertion hole into which the pipe 2 is inserted. A nut screw portion 33 is formed at the end of the nut surface 31 to be fitted to the main body screw portion 15 when the joint body 10 is fastened. Since the nut 30 is gripped and rotated by a tool such as a spanner or a wrench when fastened to the joint body 10, the outer shape when viewed from the axial direction P is a hexagonal shape.

The front ferrule 21 is a brass member having an annular shape that surrounds the periphery of the pipe 2, and the pipe 2 is inserted into a region on the inner peripheral surface side. The front ferrule 21 is disposed between the joint body 10 and the nut 30. The front ferrule 21 has a front end portion 21A (first front end portion) and a rear end portion 21B, and is configured such that the outer diameter gradually decreases from the rear end portion 21B toward the front end portion 21A. The front ferrule 21 has a distal end surface 25 that is an end surface of the distal end portion 21A, and the distal end surface 25 extends in a direction (radial direction) perpendicular to the axial direction P.

The outer diameter of the front end surface 25 is larger than the outer diameter of the main body surface 12, and the inner diameter of the front end surface 25 is substantially the same as the inner diameter of the main body surface 12. Therefore, the front ferrule 21 is disposed so that the outer peripheral edge portion of the distal end portion 21 A contacts the main body inclined surface 11 in a state before the nut 30 is fastened (FIG. 2).

The rear end portion 21B of the front ferrule 21 is provided with a rear end surface 21D substantially perpendicular to the axial direction P (substantially parallel to the radial direction) and a rear end inclined surface 21C connected to the inner end of the rear end surface 21D. ing. The rear end inclined surface 21C is inclined at a predetermined angle with respect to the radial direction so that the axial length of the front ferrule 21 decreases toward the inner side in the radial direction. In a state before the nut 30 is fastened (FIG. 2), a front end portion 22A of a back ferrule 22 described later contacts the rear end inclined surface 21C.

The outer peripheral surface of the front ferrule 21 is configured as a ferrule inclined surface 23 that faces the main body inclined surface 11 in the radial direction. The ferrule inclined surface 23 is inclined with respect to the axial direction P at a second inclination angle θ2 smaller than the first inclination angle θ1 of the main body inclined surface 11. The difference (θ1−θ2) between the first inclination angle θ1 and the second inclination angle θ2 is not particularly limited, but is preferably in the range of 3 ° to 10 °.

Like the front ferrule 21, the back ferrule 22 is a brass member having an annular shape surrounding the pipe 2, and the pipe 2 is inserted into a region on the inner peripheral surface side. As shown in FIG. 2, the back ferrule 22 has substantially the same outer diameter and inner diameter as the front ferrule 21, and the axial length is smaller than that of the front ferrule 21. The back ferrule 22 is disposed between the joint body 10 and the nut 30 and is adjacent to the front ferrule 21 in the axial direction P.

The back ferrule 22 has a front end portion 22A and a rear end portion 22B, and is configured such that the outer diameter gradually decreases from the rear end portion 22B toward the front end portion 22A. The back ferrule 22 is disposed so that the front end portion 22 A contacts the rear end inclined surface 21 C of the front ferrule 21 and the rear end portion 22 B contacts the nut inclined surface 32 before the nut 30 is fastened.

<Pipe clearance ratio of pipe joint>
Next, the tip thickness of the front ferrule 21 in the pipe joint 1, the gap between the joint body 10 and the pipe 2, and the relationship between them will be described with reference to FIG.

The thickness T1 of the front end portion 21A of the front ferrule 21 in the radial direction is set to 0.15 mm or more and 0.60 mm or less, more specifically 0.2 mm or more and 0.5 mm or less. The thickness T1 is the width in the radial direction of the distal end surface 25 that connects the inner peripheral surface 24 and the outer peripheral surface 23 (ferrule inclined surface) of the front ferrule 21 in the sectional view of FIG.

The pipe gap D1 which is a gap in the radial direction between the main body surface 12 of the joint body 10 and the outer peripheral surface of the pipe 2 is provided to be substantially constant in the axial direction P. The pipe gap D1 is (D2-D3) / 2, where D2 is the inner diameter of the joint body 10 including the main body surface 12, and D3 is the outer diameter of the pipe 2. In the pipe joint 1, a pipe gap ratio (pipe gap D1 (mm) / thickness T1 (mm)), which is a ratio of the pipe gap D1 to the thickness T1, is set to 0.3 or more and 0.8 or less, more specifically. Is set to 0.3 or more and 0.5 or less.

<Deformation process of ferrule and piping during nut fastening>
Next, the deformation process of the

ferrules

21 and 22 and the pipe 2 when the nut 30 of the pipe joint 1 is fastened will be described with reference to FIGS. FIG. 2 shows a state before the nut 30 is tightened. FIG. 4 shows a state in which the front end 21 A of the front ferrule 21 is deformed during the tightening of the nut 30. FIG. 5 shows a state after the tightening of the nut 30 is completed.

First, the pipe 2 is inserted into the joint body 10 as shown in FIG. Next, the front ferrule 21 and the back ferrule 22 are fitted into the pipe 2 in order, and then the nut 30 is fitted onto the joint body 10. Then, when the nut 30 is rotated and moved toward the joint body 10 in the axial direction P, tightening of the nut 30 is started. At this time, the back ferrule 22 is moved in the axial direction P by the rear end portion 22B being pushed by the nut inclined surface 32, and the front ferrule 21 is pushed in the axial direction P by the rear end portion 21B being pushed by the front end portion 22A of the back ferrule 22. Move to.

The front end 21A of the front ferrule 21 starts to be deformed radially inward by being pressed against the main body inclined surface 11 as shown in FIG. Then, when the distal end portion 21A is deformed by the piping gap D1, it contacts the surface of the piping 2. As a result, the outer periphery of the pipe 2 is constrained by the tip portion 21 A of the front ferrule 21.

Thereafter, the tightening of the nut 30 further proceeds, so that the surface of the pipe 2 is pressed by the front end portion 21 A of the front ferrule 21. Thereby, as shown in FIG. 5, the front end portion 21A of the front ferrule 21 bites into the surface of the pipe 2, and the pipe 2 is deformed radially inward.

On the other hand, the front end 22A of the back ferrule 22 is deformed radially inward by being pressed against the rear end inclined surface 21C of the front ferrule 21. Thereby, the back ferrule 22 restrains the outer periphery of the pipe 2 by the tip portion 22 A, similarly to the front ferrule 21. Then, as shown in FIG. 5, the pipe 2 can be deformed radially inward like the front ferrule 21 by causing the tip 22 A to bite into the surface of the pipe 2. In this way, the piping 2 is deformed, and when the deformation amount reaches a predetermined amount, the tightening of the nut 30 is completed.

<Effect>
Next, the effect by the said pipe joint 1 is demonstrated.

The pipe joint 1 is a bite-type pipe joint for connecting pipes 2 having an outer diameter of 19.05 mm or more and 38.10 mm or less, and includes a joint body 10 and a front ferrule 21. In the pipe joint 1, a pipe gap ratio (D1 / D1), which is a ratio of a gap (pipe gap) D1 in the radial direction between the joint body 10 and the pipe 2 to a thickness T1 in the radial direction of the distal end portion 21A of the front ferrule 21. T1) is 0.3 or more and 0.8 or less.

The deformation amount of the front ferrule 21 when the nut of the pipe joint 1 is fastened includes a deformation amount corresponding to the pipe gap D1 and a deformation amount corresponding to the deformation of the pipe 2. When the pipe gap ratio (D1 / T1) exceeds 0.8, the pipe gap D1 is large and the thickness T1 of the ferrule tip is small. When the pipe gap D1 increases, the ratio of the amount of change that does not contribute to the deformation of the pipe 2 in the total deformation amount of the front ferrule 21 increases.

Further, when the thickness T1 of the front end portion 21A of the front ferrule 21 is reduced, the strength thereof is reduced. Therefore, when the surface of the pipe 2 is pressed by the tip portion 21A, the tip portion 21A warps as shown in FIG. The deformation amount of the front ferrule 21 due to the warping does not contribute to the deformation of the pipe 2. Thus, the phenomenon in which the tip portion 21A is warped remarkably appears when the pipe gap D1 is large. This is because the tip portion 21A after being warped easily enters the piping gap D1 as shown in FIG.

Therefore, when the pipe gap ratio exceeds 0.8, the deformation amount that does not contribute to the deformation of the pipe 2 out of the total deformation amount of the front ferrule 21 (the deformation amount corresponding to the pipe gap D1, the warping of the tip portion 21A of the front ferrule 21) (Deformation amount due to) increases. Therefore, it is necessary to increase the amount of deformation of the front ferrule 21 necessary for obtaining a desired amount of deformation of the pipe 2, and as a result, the tightening torque is greatly increased.

On the other hand, when the pipe gap ratio is less than 0.3, the thickness T1 of the front end portion 21A of the front ferrule 21 is large and the pipe gap D1 is small. As the thickness T1 of the distal end portion 21A increases, the torque required for the deformation increases. As a result, the tightening torque required to obtain the desired amount of deformation of the pipe 2 increases. Since the outer diameter of the pipe 2 is 19.05 mm or more and 38.10 mm or less, an increase in the tightening torque deteriorates workability.

Here, the change in the tightening torque due to the thickness of the ferrule tip as described above will be described with reference to the graph of FIG. The graph in FIG. 7A shows the relationship between the nut rotation angle and the ferrule deformation amount. In the graph of FIG. 7A, the horizontal axis indicates the nut rotation angle, and the vertical axis indicates the ferrule deformation amount. The graph in FIG. 7B shows the relationship between the nut rotation angle and the tightening torque. In the graph of FIG. 7B, the horizontal axis represents the nut rotation angle, and the vertical axis represents the tightening torque. The nut rotation angle on the horizontal axis corresponds to the amount of nut movement in the axial direction.

In the graphs of FIGS. 7A and 7B, (1) is when the ferrule tip thickness is large, (2) is when the ferrule tip thickness is smaller than (1), and (3) is when the ferrule tip thickness is from (2). Each shows a small case where the tip is warped.

In any of the cases (1) to (3), the ferrule deformation amount increases as the nut rotation angle increases (FIG. 7A), and the tightening torque also increases (FIG. 7B). Then, the deformation of the pipe starts from the time (the pipe deformation amount zero point) that is deformed by the pipe gap from the ferrule deformation amount zero point. Then, when the desired amount of pipe deformation is reached (tightening completion point), tightening of the nut is completed.

First, comparing the cases of (1) and (2) with the same pipe deformation at the tightening completion point, the thickness of the ferrule tip is smaller (2) than in the case of (1). As a result, the tightening torque becomes small (t2 <t1).

Next, comparing the cases of (2) and (3) at the same nut rotation angle, the amount of pipe deformation is smaller in the case of (3) in which the ferrule tip is warped than in the case of (2). . Therefore, in the case of (3), the nut rotation angle necessary for obtaining the same pipe deformation amount as in the case of (2) is increased, and as a result, the tightening torque is also increased (t2 <t3).

In the pipe joint 1, the thickness T1 and the pipe gap D1 of the front end portion 21A of the front ferrule 21 are set so that the pipe gap ratio (D1 / T1) is in the range of 0.3 to 0.8. Yes. Therefore, according to the said pipe joint 1, the fastening torque required in order to obtain the desired amount of pipe deformation can be reduced, and the workability of pipe connection can be further improved.

In the pipe joint 1, the thickness T1 of the front end portion 21A of the front ferrule 21 is not less than 0.15 mm and not more than 0.60 mm. When the thickness T1 exceeds 0.60 mm, the strength at the distal end portion 21A increases, so that the torque required for deformation increases. On the other hand, when the thickness T1 is less than 0.15 mm, the strength of the distal end portion 21A decreases, so that warping tends to occur, and the tightening torque necessary to obtain a desired amount of pipe deformation increases. Therefore, the thickness T1 is set in the range of 0.15 mm or more and 0.60 mm or less from the viewpoint of securing a desired amount of pipe deformation and reducing the tightening torque.

In the pipe joint 1, the ratio of the radial thickness T0 of the pipe 2 to the outer diameter of the pipe 2 is 0.03 or more and 0.13 or less. When the ratio of the wall thickness to the outer diameter of the pipe 2 exceeds 0.13, the wall thickness becomes excessive with respect to the outer diameter of the pipe 2, and the amount of fluid flowing in the pipe 2 decreases. On the other hand, when it is less than 0.03, the wall thickness becomes excessively small with respect to the outer diameter of the pipe 2, and the strength of the pipe 2 is lowered. Therefore, the ratio of the wall thickness to the outer diameter of the pipe 2 is set to 0.03 or more and 0.13 or less.

The pipe joint 1 includes a back ferrule 22 that deforms radially inward by deforming the pipe 2 by contacting the front ferrule 21. Thereby, the holding power and airtightness of the pipe 2 can be improved as compared with a single ferrule-type pipe joint. The back ferrule 22 is not an essential configuration and may be omitted.

In the pipe joint 1, the joint main body 10 has a main body inclined surface 11 that is inclined with respect to the axial direction P at the first inclination angle θ 1. The front ferrule 21 is disposed so that the tip 21A abuts against the main body inclined surface 11 in a state (FIG. 2) before the nut is fastened. The front ferrule 21 has a ferrule inclined surface 23 that is inclined with respect to the axial direction P at a second inclination angle θ2 that is smaller than the first inclination angle θ1. Thereby, the front ferrule 21 can be smoothly moved in the axial direction P so that the tip 21 A follows the inclined body 11 when the nut is fastened.

<Pipe outer diameter design>
The reason why the outer diameter of the pipe 2 is set in the range of 19.05 mm or more and 38.10 mm or less will be described with reference to FIG. FIG. 8 is a graph showing the relationship between the pipe outer diameter (horizontal axis) and the ratio of the pipe gap to the pipe outer diameter (vertical axis).

In the bite-in type pipe joint, basically, the pipe gap and the ferrule tip thickness increase as the pipe outer diameter increases. The pipe gap is set to facilitate the insertion of the pipe at the time of construction, but the pipe tolerance (including roundness) changes around the outer diameter of 19.05 mm. There is an inflection point in relation to the outer diameter. That is, the inclination is different between the pipe outer diameter of less than 19.05 mm (especially 15.88 mm or less) and 19.05 mm or more, and when it is less than 19.05 mm, the pipe gap is the original value. Is set larger than. Therefore, in this embodiment, the lower limit value of the outer diameter of the pipe 2 is set to 19.05 mm in order to clearly define the relationship (pipe gap ratio) between the pipe gap and the ferrule tip thickness.

Also, when the outer diameter of the pipe 2 exceeds 38.10 mm, the pipe gap and the ferrule tip are excessively thick, so that the tightening torque is greatly increased. Therefore, in this embodiment, the upper limit value of the outer diameter of the pipe 2 is set to 38.10 mm.

<Modification 1>
Next, the shape of the front ferrule 41 which concerns on the modification 1 of the said embodiment is demonstrated with reference to FIG. FIG. 9 is an enlarged view of the front ferrule 41 according to the first modification in the vicinity of the first tip portion 41A.

The front end surface 45 of the front ferrule 41 includes a flat surface portion 48 located on the inner diameter side, and a first curved surface portion 46 connected to the flat surface portion 48 and located on the outer diameter side. That is, the front ferrule 41 is modified so as to exclude the corner (the hatched portion in FIG. 9) on the outer diameter side in the shape exemplified in the above embodiment. The thickness T2 in the radial direction of the first tip portion 41A includes a connection point P1 between the tip surface 45 and the inner peripheral surface 44, an extension line of the tip surface 45 (broken line in the figure), and an extension line of the ferrule inclined surface 43 (see FIG. It is defined by the length between the intersection point P2 and the middle broken line).

<Modification 2>
Next, the shape of the front ferrule 51 which concerns on the modification 2 of the said embodiment is demonstrated with reference to FIG. FIG. 10 is an enlarged view of the front ferrule 51 according to the second modification in the vicinity of the first tip 51A.

The front end surface 55 of the front ferrule 51 includes a second curved surface portion 58 located on the inner diameter side and a third curved surface portion 56 located on the outer diameter side. That is, the front ferrule 51 is modified so as to exclude the corner portions (shaded portions in FIG. 10) on the inner diameter side and the outer diameter side in the shape exemplified in the above embodiment. A straight line L1 connecting the extension line of the inner peripheral surface 54 and the extension line of the ferrule inclined surface 53 is in contact with the tip surface 55 at the contact point P1. The thickness T3 in the radial direction of the first tip 51A is defined by the length of the straight line L1.

<Experimental example>
The effect of the ratio of the pipe gap to the thickness of the front ferrule tip (pipe gap ratio: pipe gap / front ferrule tip thickness) on the tightening torque was investigated. Specifically, pipe joints designed for various pipe clearance ratios were prepared, and the tightening torque when the pipe deformation amount was made constant was measured. Then, the relationship between the piping gap ratio and the tightening torque was investigated.

FIG. 11 is a graph showing the survey results. In the graph of FIG. 11, the horizontal axis indicates the piping gap ratio, and the vertical axis indicates the number of deformation torques. Here, the number of deformation torques is defined to exclude the influence of the pipe outer diameter from the measured tightening torque data, and the measured value of the tightening torque is divided by the square value of the pipe outer diameter. Can be obtained.

As is apparent from FIG. 11, the deformation torque is increased when the pipe gap ratio is in the range of 0.3 to 0.8, compared to the case where the pipe gap ratio exceeds 0.8 and below 0.3. The number has become smaller. In particular, there was a minimum value of the number of deformation torques within the piping gap ratio range of 0.3 to 0.5. From this result, the tightening torque required to obtain a predetermined amount of pipe deformation is reduced by setting the pipe gap ratio to 0.3 to 0.8 (preferably 0.3 to 0.5). I found it possible.

The outline of the above embodiment is as follows.

The pipe joint according to the present embodiment is a bite-type pipe joint for connecting pipes having an outer diameter of 19.05 mm or more and 38.10 mm or less. The pipe joint includes a joint body into which the pipe is inserted, and a first ferrule having a ring shape surrounding the circumference of the pipe and having a first tip portion. In the pipe joint, a pipe gap ratio that is a ratio of a gap in the radial direction between the joint body and the pipe to a thickness in the radial direction of the ring shape of the first tip portion is 0.3 or more and 0. .8 or less.

Further, the pipe connection structure according to the present embodiment includes a pipe having an outer diameter of 19.05 mm or more and 38.10 mm or less, and the pipe joint for connecting the pipes. Moreover, the air conditioning apparatus which concerns on this embodiment is an outer diameter of 19.05 mm or more and 38.10 mm or less, and is provided with the piping through which a refrigerant | coolant passes, and the said pipe joint for connecting the said piping.

In the bite type pipe joint that connects pipes having an outer diameter of 19.05 mm or more and 38.10 mm or less, the present inventors have provided a measure for sufficiently securing the deformation amount of the pipe and reducing the tightening torque. We conducted an intensive study. As a result, the present inventors define the ratio of the pipe gap (gap between the joint body and the pipe) to the thickness of the ferrule tip (pipe gap ratio: pipe gap / ferrule tip thickness) within a predetermined range. As a result, the inventors have found that the above-mentioned problems can be solved and have arrived at the present invention.

In a bite-in type pipe joint, the tightening torque increases as the ferrule deformation increases, and the pipe holding force increases as the pipe deformation increases. When the pipe gap ratio exceeds 0.8, the pipe gap is large and the thickness of the ferrule tip is small. When the pipe gap increases, the ratio of the ferrule change amount corresponding to the pipe gap in the total ferrule deformation amount increases, but this change amount does not contribute to the pipe deformation. Further, when the thickness of the ferrule tip is reduced, the strength is lowered, so that the tip portion warps when pressed against the pipe surface. The deformation amount of the ferrule due to this warping does not contribute to the deformation of the pipe. Therefore, when the pipe gap ratio exceeds 0.8, the ratio of the deformation amount that does not contribute to pipe deformation (the deformation amount corresponding to the pipe gap and the deformation amount due to warping of the tip) out of the total ferrule deformation amount increases. . Therefore, it is necessary to increase the deformation amount of the ferrule necessary for obtaining a desired piping deformation amount, and as a result, the tightening torque is greatly increased.

On the other hand, when the pipe gap ratio is less than 0.3, the thickness of the ferrule tip is large and the pipe gap is small. When the thickness of the ferrule tip increases, the torque necessary for the deformation increases, and as a result, the tightening torque necessary for obtaining a desired amount of pipe deformation increases.

On the other hand, in the pipe joint, the ratio of the gap in the radial direction between the joint body and the pipe (pipe gap ratio) with respect to the thickness in the radial direction of the first tip of the first ferrule is 0. It is specified in the range of 3 to 0.8. Therefore, according to the pipe joint, it is possible to further reduce the tightening torque necessary to obtain a desired amount of pipe deformation. Therefore, according to the above pipe joint, it is possible to provide a pipe joint with excellent workability by ensuring a sufficient amount of deformation of the pipe and reducing the tightening torque.

In the pipe joint, it is preferable that the thickness of the first tip portion in the radial direction is not less than 0.15 mm and not more than 0.60 mm.

When the thickness exceeds 0.60 mm, the strength at the first tip increases, so the torque required for deformation increases. On the other hand, when the thickness is less than 0.15 mm, the strength of the first tip portion is reduced, so that warping is likely to occur, and the tightening torque required to obtain a desired amount of pipe deformation increases. Therefore, from the viewpoint of securing a desired amount of pipe deformation and reducing the tightening torque, the thickness is preferably in the range of 0.15 mm to 0.60 mm.

In the pipe joint, it is preferable that a ratio of a radial thickness of the pipe to an outer diameter of the pipe is 0.03 or more and 0.13 or less.

When the ratio of the wall thickness to the outer diameter of the pipe exceeds 0.13, the wall thickness becomes excessive with respect to the outer diameter of the pipe, and the amount of fluid flowing in the pipe decreases. On the other hand, when it is less than 0.03, the wall thickness becomes excessively small with respect to the outer diameter of the pipe, and the strength of the pipe decreases. Therefore, the ratio of the wall thickness to the outer diameter of the pipe is preferably 0.03 or more and 0.13 or less.

The pipe joint has an annular shape surrounding the circumference of the pipe, and further includes a second ferrule that deforms the pipe by deforming radially inward of the ring shape by contacting the first ferrule. It is preferable.

According to the above configuration, the holding force of the pipe can be improved by deforming the second ferrule and causing it to bite into the pipe as compared with the case where only the first ferrule is provided.

In the pipe joint, it is preferable that the joint main body has a main body inclined surface that is an inner peripheral surface inclined at a first inclination angle with respect to the axial direction of the pipe. It is preferable that the first ferrule is disposed so that the first tip portion is in contact with the main body inclined surface. The first ferrule has a ferrule inclined surface that faces the main body inclined surface and is inclined with respect to the axial direction at a second inclination angle smaller than the first inclination angle. preferable.

According to the above configuration, the first ferrule can be smoothly moved in the axial direction so that the first tip portion is along the inclined surface of the main body.

In the above pipe joint, the joint body is preferably made of brass. The piping is preferably made of copper.

According to the above configuration, by selecting relatively soft copper as the material of the pipe, the first ferrule can be easily bited into the surface of the pipe. Further, by selecting brass as the material of the joint body, it is possible to prevent deformation when the first ferrule contacts the joint body.

Claims

A bite type pipe joint for connecting pipes having an outer diameter of 19.05 mm or more and 38.10 mm or less,
A joint body into which the pipe is inserted;
A first ferrule having a ring shape surrounding the periphery of the pipe and having a first tip;
A pipe gap ratio, which is a ratio of a gap in the radial direction between the joint body and the pipe, to a thickness in the radial direction of the ring shape of the first tip is 0.3 or more and 0.8 or less. , Pipe fittings.
The pipe joint according to claim 1, wherein the thickness of the first tip portion in the radial direction is not less than 0.15 mm and not more than 0.60 mm.
The pipe joint according to claim 1 or 2, wherein a ratio of a radial thickness of the pipe to an outer diameter of the pipe is 0.03 or more and 0.13 or less.
2. A second ferrule that has a ring shape surrounding the periphery of the pipe and further deforms the pipe by deforming the ring shape radially inward by contacting the first ferrule. 4. The pipe joint according to any one of items 1 to 3.
The joint body has a main body inclined surface that is an inner peripheral surface inclined at a first inclination angle with respect to the axial direction of the pipe,
The first ferrule is:
The first tip is disposed so as to contact the inclined body surface,
The ferrule inclined surface that is opposed to the main body inclined surface and is inclined with respect to the axial direction at a second inclination angle smaller than the first inclination angle. Pipe fittings.
The joint body is made of brass,
The pipe joint according to any one of claims 1 to 5, wherein the pipe is made of copper.
A pipe having an outer diameter of 19.05 mm or more and 38.10 mm or less;
A pipe connection structure comprising: the pipe joint according to any one of claims 1 to 6 for connecting the pipes together.
A pipe having an outer diameter of 19.05 mm or more and 38.10 mm or less, through which the refrigerant passes;
An air conditioner comprising: the pipe joint according to any one of claims 1 to 6 for connecting the pipes together.