JP5961692B2 - Fittings and fitting assemblies - Google Patents

Description

  The present invention relates to a joint and a joint assembly.

  Conventionally, for example, as described in Patent Document 1 (Japanese Patent Application Laid-Open No. 2009-144916), a tube joint that can be firmly connected so that fluid that passes through the tube does not leak has been proposed. Yes. Here, as an outer diameter size of a tube to which a tube joint is attached, sizes of 1/4 inch, 3/8 inch, 1/2 inch, 3/4 inch, and 1 inch are proposed.

  In this tube joint, when a tube is attached to the end of a tubular joint body and the connection nut is screwed to the joint body, a fixing ring is provided between the joint body and the connection nut. When the connection nut is screwed onto the joint body, the tube is tightened by the joint body from the inside and by a fixing ring pressed by the connection nut from the outside.

  In this tube joint, by adopting the above configuration, when the connection nut is screwed onto the joint body, the connection nut rotates relative to the tube, but the fixing ring rotates relative to the tube. Because there is nothing, it is said that the outer surface of the tube could be prevented from having an annular scratch or being cut.

  In addition, by making the fixing ring harder than the tube, the connection is strengthened so that the tube does not come out of the tube joint, and the connection nut is deformed when the connection nut is fixed to the joint body. It can be prevented from occurring (see paragraph number 0021 of Cited Document 1).

  Thus, in the joint as described in the above-mentioned Patent Document 1 (Japanese Patent Laid-Open No. 2009-144916), a maximum outer diameter size of 1 inch has been proposed.

  The inventors have attempted to develop a large-sized tube that can secure a large flow rate of fluid flowing through the tube and a tube joint connected to the tube.

  And it became clear that in a tube joint used for a large-sized tube, the tube is easy to come out and fluid leaks more easily than a small-sized tube joint.

  On the other hand, it is possible to make it difficult to remove the tube from the tube joint by making the fixing ring harder than the tube. However, when the elastic modulus of the fixing ring is too high, the bending of the fixing ring when the connecting nut is screwed onto the joint body is very small, and the tube is tightened excessively from the outside in the radial direction to the inside. The tube may be cut.

  In this case, the elastic modulus of the fixing ring has a desirable range in which it is difficult to damage the outer surface of the tube while preventing the tube from coming off. And, by designing the fixing ring so as to have an elastic modulus in the desired range, in a state where the tube is firmly connected to the tube joint, from the radially outer side of the tube to the radially inner side with respect to the outer surface of the tube. The elastic force of the fixing ring can be applied to the tube, the tube can be clamped with an appropriate force by the fixing ring and the joint body, and the connection can be strengthened while preventing the tube from being cut. Become.

  However, as described above, the tube is pulled or bent in a state in which the tube is connected to the tube joint so that the tube can be firmly connected while cutting the tube is suppressed. Some external force may act on the. Thus, in the above-mentioned connection state, when an external force acts on the tube, the fixing ring may extend radially outward beyond its own elastic region. In this way, when an external force acts on the tube and the fixing ring is in a state beyond its own elastic region, the force from the radially outer side of the fixing ring toward the radially inner side is less likely to act on the tube, It may become easy to come off from the tube joint.

  The present invention has been made in view of the above-described points, and an object of the present invention is to provide a joint and a joint assembly that can suppress tube disconnection and fluid leakage even when the size is large. It is to provide.

The joint according to the first aspect is a joint connected to a tube having at least an inner surface made of resin, and includes a main body, a nut, and at least one ring. The main body includes a tube connecting portion provided at one end, and a main body thread portion provided so that an outer diameter of the outer peripheral surface is larger than that of the tube connecting portion. A through hole extending in the axial direction is formed in the main body. Nut, have a nut screw peaks and reduced diameter portion and the abutted portion, the elastic modulus is less than 800MPa or more 400 MPa. The nut thread portion can be screwed into the main body thread portion of the main body in a state where the tube connecting portion of the main body is inserted from one end side in the axial direction toward the other end side in the axial direction with respect to the nut. The reduced diameter portion is provided on the other end side in the axial direction of the nut and has an inner diameter smaller than that of the nut screw thread portion. The contacted portion is formed so as to face one end side in the axial direction with respect to the reduced diameter portion. At least one ring has an elastic modulus of 1000 MPa or more and 2500 MPa or less, is arranged in a space radially inward of the nut thread portion of the nut, has an elastic modulus higher than that of the tube, and abuts against a contacted portion of the nut. . When the ring is in the elastic region, a radial gap is provided between the outer peripheral portion of the ring and the inner peripheral portion of the nut located on the radially outer side of the ring. The ring is configured to exceed the elastic region at a stage before contacting the radially inner surface of the nut when the ring spreads radially outward. The ring has an elastic modulus that satisfies the following conditions. That is, when the main body, nut, and ring are connected to the tube, when the ring is in the elastic region, the ring is directed from the radially outer side to the radially inner side by its own stress. It is possible to push. In addition, when the main body, nut and ring are connected to the tube, when the ring exceeds the elastic region, the expanded ring is pushed radially inward by the radially inner surface of the nut. Thus, the tube can be pushed from the radially outer side toward the radially inner side.

  When the tube is attached to the main body so that the inner surface of the tube is in contact with the outer surface of the tube connecting portion of the main body, the nut threaded portion of the nut is screwed into the main body threaded portion of the main body and screwed in. The ring located outside the tube comes into contact with the contacted portion of the nut and approaches the end of the tube connecting portion of the main body. Then, in a state where a part of the tube is sandwiched between the ring and the end of the tube connecting portion of the main body, the ring is elastically deformed so as to spread outward in the radial direction. In the elastic state in which the ring is elastically deformed in this manner, the elastic force can be applied to the tube so as to press the tube from the radially outer side to the radially inner side.

  Here, even if this joint is connected to a tube made of resin, it uses a ring whose elastic modulus is higher than the elastic modulus of the tube. The tube can be firmly fixed to make it difficult to pull out the tube, and the leakage of fluid passing through the inside of the tube can be suppressed.

  Moreover, even when some external force is applied to the tube in a state where the nut is screwed onto the main body and the joint is fixed to the tube, it is possible to make the tube difficult to pull out by the elastic modulus of the ring. . In addition, when some external force is further applied to the tube in a state where the joint is fixed to the tube, the ring can be deformed so as to further expand and exceed the elastic region. Thereby, it can prevent that a tube is tightened too much and it can control that a tube will be cut.

  Even when the ring expands and deforms beyond the elastic region in this way, the expanded ring has a radially outer portion in contact with the radially inner surface of the nut, It is pushed radially inward by the inner peripheral part. In this way, the ring that is pushed radially inward by the nut pushes the tube from the radially outer side toward the radially inner side to fasten and fix the tube, making it difficult to pull out the tube, It is possible to suppress the leakage of fluid passing through the.

  As described above, according to this joint, even when the size of the tube is large, it is possible to suppress disconnection of the tube and fluid leakage while suppressing the tube from being cut.

Further, in this joint, when the tube is fixed by the elastic force of the ring in a state where the ring is elastically deformed, the outer peripheral portion of the ring is outside the inner peripheral portion of the nut in the radially outer side of the ring. Do not touch the part where it is located. For this reason, in a state where the ring is elastically deformed, when the tube is fixed by the elastic force of the ring, the nut can be prevented from being deformed so as to be expanded radially outward. ing.

In this joint, the elastic modulus of the ring is not only higher than the elastic modulus of the tube, but also higher than that of the nut. For this reason, even if the ring is deformed so that it exceeds the elastic region and the outer peripheral part of the ring comes into contact with the inner peripheral part of the nut and is pushed radially inward, the elasticity of the nut Since the rate is not as high as the elastic modulus of the ring, it is possible to prevent the tube from being tightened excessively and to prevent the tube from being cut.

Joint according to the second aspect is the joint according to the first view point, the shape of the cross section of the circumferential ring and the normal direction, of the rectangular shape, the body side in the axial direction and at least the radially inner side This is a chamfered shape or a rounded shape. The chamfered or rounded portion of the ring-side portion on the radially inner side of the ring is a portion of 0.3% to 40% of the radial width of the ring, It is a portion of 1% to 40% of the axial width of the ring.

  In this joint, when the nut is screwed into the main body, the tube is sandwiched between the end of the tube connecting portion of the main body and the ring. At this time, the ring is located on the inner side in the radial direction of the ring. It is in contact with the tube at the part on the main body side in the direction. And in this joint, it is a portion on the inner side in the radial direction of the ring and on the main body side in the axial direction (a portion not less than 0.3% and not more than 40% of the radial width of the ring). The portion between 1% and 40%) is chamfered or rounded. For this reason, even when a joint using a ring having a higher elastic modulus than the tube is connected and fixed to the tube, a corner is provided without adopting a chamfered shape or a rounded shape. Compared with the case where it is, the local pressing force can be made hard to act on the tube from the ring. Thereby, it is possible to suppress the cutting of the tube. In addition, the portion on the radially inner side of the ring and on the main body side in the axial direction (a portion of 0.3% to 40% of the radial width of the ring and 1% to 40% of the axial width of the ring) %), The contact area with the outer surface of the tube can be made not too wide, so that the force with which the tube is pressed by the ring is dispersed and the tube is easily pulled out. It can be suppressed.

The joint according to the third aspect is the joint according to the second aspect , wherein the chamfered or rounded portion in the axially main body side portion is the radial direction of the ring. 3% to 29% of the width of the ring, and 2% to 25% of the axial width of the ring.

  In this joint, it is possible to secure the tensile strength by biting the ring into the tube while further reducing the possibility of the tube being cut.

The joint according to the fourth aspect is the joint according to any one of the first aspect to the third aspect , when the ring is in a state in the elastic region in a state where the main body, the nut and the ring are connected to the tube. Of the inner circumference of the nut, the inner diameter of the portion located radially outside the portion with the largest outer diameter of the ring is X, and the outer diameter of the portion with the largest outer diameter of the ring is Y In the state where the nut and the ring are not connected and no force is applied, the length of the portion corresponding to X and Y is such that the value of (XY) / Y is 0.003 or more and 0.020 It is as follows.

  In this joint, when the ring is connected to the tube and the ring is expanded, the ring can be more reliably brought out of the elastic state before the contact with the inner peripheral portion of the nut. Thereby, it can suppress more reliably that a tube will be pressed too much and will be cut | disconnected by contacting the inner peripheral part of a nut with an elastic state.

The joint according to the fifth aspect is the joint according to any one of the first to fourth aspects, in the case where the ring is in a state in the elastic region with the main body, the nut, and the ring connected to the tube. Of the inner peripheral portion of the nut, the inner diameter of the portion located radially outward with respect to the portion where the outer diameter of the ring is maximum is X, the outer diameter of the portion where the outer diameter of the ring is maximum is Y, and the tube The length of the portion corresponding to X, Y, and Z in a state where the nut, the ring, and the tube are not connected to each other and no force is applied thereto is defined as (XY). ) / Z is 0.04 or more and 0.30 or less.

  In this joint, when the tube is crushed as it is connected to the tube and the ring is expanded, the state of the ring is more reliably secured before the tube is excessively crushed and cut. Can be made to exceed the elastic region. Thereby, it can suppress more reliably that a tube is cut | disconnected.

A joint according to a sixth aspect is the joint according to any one of the first to fifth aspects, wherein the tube is made of a resin composition containing at least one selected from the group consisting of PFA, FEP, and PTFE. Yes. The nut is made of a resin composition containing at least one selected from the group consisting of PFA, PCTFE, PVDF, ETFE, and PPS. The ring is composed of a resin composition containing at least one selected from the group consisting of PCTFE, PVDF, ETFE, and PPS.

  With this joint, it is possible to more reliably suppress disconnection of the tube and fluid leakage while more reliably suppressing the tube from being cut.

In the joint according to the seventh aspect , in the joint according to any one of the first to sixth aspects, the ring is opaque. The nut is transparent or translucent.

  In this joint, since the nut is transparent or translucent and the ring is opaque, the presence of the ring can be visually recognized from the outside of the nut in a state where the ring and the nut are connected to the tube. Thereby, it is possible to make it difficult to forget to attach the ring.

A joint assembly according to an eighth aspect includes a tube and the joint according to any one of the first to seventh aspects. The tube includes a resin having chemical resistance. The bending radius of the tube is 0.3 m or more and 3.0 m or less.

  In this joint assembly, unlike tubes made of iron, the tube is easy to bend, so even if it is necessary to transport a long tube to the site in order to connect a long distance, it is wrapped around It can be made compact.

In the joint according to the first aspect, even when the tube size is large, it is possible to suppress disconnection of the tube and fluid leakage while suppressing the tube from being cut. Further, in the state where the ring is elastically deformed, when the tube is fixed by the elastic force of the ring, the nut can be prevented from being deformed so as to be expanded radially outward. Yes. Even if the ring is deformed so that it exceeds the elastic region and the outer peripheral part of the ring comes into contact with the inner peripheral part of the nut and is pushed radially inward, the tube is cut. It is possible to suppress this.

In the joint according to the second aspect, it is possible to make the tube difficult to cut and to prevent the tube from coming off.

In the joint according to the third aspect, it is possible to secure the tensile strength by biting the ring into the tube while further reducing the possibility of the tube being cut.

In the joint which concerns on a 4th viewpoint, it can suppress more reliably that a tube will be cut | disconnected by contacting the inner peripheral part of a nut with a ring being an elastic state.

In the joint according to the fifth aspect , the tube can be more reliably suppressed from being cut.

In the joint according to the sixth aspect, it is possible to more reliably suppress the disconnection of the tube and the leakage of the fluid while more reliably suppressing the tube from being cut.

In the joint according to the seventh aspect, forgetting to attach the ring can be suppressed.

In the joint assembly according to the eighth aspect , the joint assembly can be made compact.

It is a disassembled perspective view regarding the outline of the appearance of the joint and joint assembly concerning an example. It is a side view of a main body. It is a side view sectional view of a main part. It is the figure which looked at the main body from the opposite side to the side in which a tube is inserted in an axial direction. It is a side view of a ring. It is a side view of a nut. It is a side view sectional view of a nut. It is the figure which looked at the nut from the reduced diameter part side in the axial direction. It is side view sectional drawing of the state which attached the ring and nut to the tube. It is sectional drawing in side view of the state which connected the tube by which the front-end | tip pipe was expanded to the main body. It is side view sectional drawing which shows a mode that a nut is screwed with respect to a main body. It is a side view outline sectional view in the state where the joint was connected and fixed to the tube. FIG. 4 is a partially enlarged schematic cross-sectional view in a side view in a state where a joint is connected and fixed to a tube. It is a side view partial expansion schematic sectional drawing which shows the other example regarding the state by which the coupling was connected and fixed to the tube. FIG. 4 is a partially enlarged schematic cross-sectional view in a side view in a state where a joint is connected and fixed to a tube. It is side view sectional drawing which shows the connection fixed state of the joint which concerns on other embodiment (7-1). It is side surface sectional drawing which shows the connection fixed state of the joint which concerns on other embodiment (7-2).

  Below, the joint and joint assembly concerning one embodiment are explained. The joints and joint assemblies described below are for illustrative purposes and are not limiting.

(1) Joint and Joint Assembly The joint of the present embodiment is a joint connected to a tube, and includes a main body, a nut, and a ring. The joint assembly is configured by coupling and fixing a joint to a tube.

(2) Tube The tube is a tubular member having at least an inner surface made of resin.

  The tube only needs to have at least a radially inner surface made of a resin, and may include, for example, a metal layer in part. Moreover, the surface inside radial direction and the surface outside radial direction may be comprised with resin, and the intermediate | middle layer may be comprised with the metal. Preferably, the tube is composed of one type of resin composition.

  The fluid that passes through the inside of the tube is not particularly limited, and examples thereof include high-temperature water such as acid, alkali, solvent, and hot spring water, marine water, and industrial waste liquids. Examples of the acid include hydrochloric acid, nitric acid, hydrofluoric acid, sulfuric acid, and phosphoric acid. Examples of the alkali include aqueous ammonia, organic amines such as ethanolamine, sodium hydroxide, potassium hydroxide and the like. Examples of the solvent include alcohols such as methanol and propanol, and organic solvents such as toluene.

  The state of the fluid passing through the inside of the tube may be a pressurized state. In such a state where the fluid is pressurized, leakage from the joint portion tends to be a problem, but in the joint of this embodiment, even when such pressurized fluid flows inside, The leakage can be suppressed.

  The tube has an inner diameter of 28.0 mm or more in a state where it is not connected and fixed and no force is applied, in order to improve the workability while ensuring a larger flow rate of the fluid passing through the inside. It is preferably 0.0 mm or less, and more preferably 45.0 mm or more and 55.0 mm or less. The outer diameter of the tube is preferably greater than 38.1 mm (1.5 inches) and more preferably greater than 50.8 mm (2.0 inches). Moreover, it is preferable that the outer diameter of a tube is 70.0 mm or less. Furthermore, the outer diameter of the tube is more preferably 52.0 mm or more and 62.0 mm or less.

  The thickness of the tube is preferably 2.5 mm or greater and 4.0 mm or less, and more preferably 3.0 mm or greater and 3.5 mm or less.

  The bending radius of the tube is preferably from 0.3 m to 3.0 m, and more preferably from 0.5 m to 1.5 m. The bending radius of the tube refers to a radius immediately before the tube is bent (not broken) when the tube is bent in an arc shape.

  Note that increasing the thickness of the tube can make the tube difficult to cut, but tends to increase the bending radius. If the bending radius becomes long in this way, one tube becomes long and it becomes difficult to transport it to the site, so it is necessary to divide it into a plurality of short ones. In addition to the complexity of connection work, the increase in the number of connection points makes the leakage problem prominent. For this reason, in order to ensure the ease of carrying the tube and to ensure the ease of routing at the construction site, for example, the tube thickness is 1.0 mm or more and 10.0 mm or less, and the bending radius of the tube Is preferably 0.3 m or more and 1.5 m or less.

  In order to increase the ease of construction when the tube is connected and fixed to the joint, the tube is preferably heated and expanded at the end of the connection destination.

  The resin constituting the tube is preferably a resin having chemical resistance. Examples of the resin having chemical resistance include PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer), FEP (tetrafluoroethylene / hexafluoropropylene copolymer), PTFE (polytetrafluoroethylene), and these. Of the mixture. Among these, the resin constituting the tube is preferably PFA from the viewpoint of chemical resistance, cracking resistance, heat resistance, and mechanical properties that are difficult to break even when bent. The melting point determined by DSC (differential scanning calorimetry) of the resin and determined by the peak top is preferably 260 ° C. or higher and 310 ° C. or lower, and more preferably 295 ° C. or higher and 310 ° C. or lower. Since PFA having a melting point of 295 ° C. or higher is not too soft, deformation of the flared portion can be suppressed, and the tube can be made difficult to come off. In addition, PFA having a melting point of 310 ° C. or less is excellent in cracking resistance and is not easily cracked in the flared portion. The elastic modulus of the resin measured according to ASTM D638 is preferably 300 MPa or more and 800 MPa or less, and more preferably 400 MPa or more and 800 MPa or less.

  In addition, it is preferable that the surface roughness of a tube is 0.001 or more and 2.0 or less. The surface roughness here was measured as the arithmetic average roughness Ra (μm) on the outer surface of the tube in accordance with JIS B0601-1994 using SURFTEST SV-600 manufactured by Mitutoyo.

(3) Main body The main body has a tube connecting portion and a main body thread portion, and a through hole extending in the axial direction is formed.

  The main body thread portion is provided on the inner side in the axial direction with respect to the tube connecting portion, and has an outer diameter larger than the outer diameter of the tube connecting portion, and is configured to be screwed with the nut thread portion of the nut. .

  The main body may further include an attachment-side screw thread portion and a main body operation portion. The mounting-side thread portion is provided on the outer peripheral surface near the end opposite to the side where the tube connecting portion is provided in the axial direction, and is screwed with the thread of the mating member to which the joint is connected. Is configured to do. The main body operation portion is a portion that is clamped by a wrench or a human finger when the nut is screwed into the main body, and is provided between the main body screw thread portion and the mounting screw thread portion in the axial direction. The main body operation unit has a polygonal shape or a deformed shape when viewed in the axial direction.

  The tube connecting portion is formed in a cylindrical shape on one end side of the main body. The tube connecting portion is covered from the radially outer side by the inner surface of the tube by attaching the tube.

  The main body thread portion is provided on the outer peripheral surface so as to have an outer diameter larger than that of the tube connecting portion.

  It is preferable that the tube connection part of the main body is provided with a tube insertion end at the axially outer end. The tube insertion end has a radially outer insertion portion configured such that a radially outer portion is positioned radially inward as it goes outward in the axial direction, and a radially inner portion is radially outward as it goes outward in the axial direction. And a radially inner insertion portion configured to be located at The radially outer insertion portion may be configured by an outer inclined surface, or may be configured by an outer R portion that is outward in the axial direction and bulges toward the radially outer side and is gently curved. When the radially outer insertion portion is constituted by the outer inclined surface, the smaller one of the angles formed by the outer inclined surface and the axial direction is not connected and fixed in the axial sectional shape. In a state where no force is applied, it is preferably 30 degrees or more and 60 degrees or less. The radially inner insertion portion is preferably not constituted by an R portion which is axially outer and bulges radially inward and is gently curved, and more preferably constituted by an inner inclined surface. When the radially inner insertion portion is constituted by the R portion, there is a possibility that fluid may stay between the inner surface of the tube and the R portion of the radially inner insertion portion in a state where the joint is connected and fixed to the tube. Because. When the radially inner insertion portion is constituted by the inner inclined surface, the smaller one of the angles formed by the inner inclined surface and the axial direction is not connected and fixed in the axial sectional shape. In a state where no force is applied, it is preferably 30 degrees or more and 70 degrees or less. By setting the angle to 30 degrees or more, it is possible to avoid a decrease in strength due to a decrease in the radial thickness at the distal end of the tube connecting portion. When the joint is connected and fixed to the tube, a ring or It is easy to avoid being pushed inward by the tube and falling inward in the radial direction. Moreover, the retention of the fluid produced in the clearance gap formed between the inner side inclined surface of a tube connection part and the inner surface of a tube can be suppressed by making the said angle 70 degrees or less.

  The position of the boundary portion in the radial direction between the radially outer insertion portion and the radially inner insertion portion in the tube coupling portion of the main body is within the range of the thickness width of the tube coupling portion and closer to the radially inner side of the tube coupling portion. Preferably it is located. The diameter of the circle formed by the boundary portion is preferably smaller than the inner diameter of the ring. This prevents the tip of the boundary portion of the tube connecting portion from piercing the tube in the thickness direction of the tube in a state where the tube is connected and fixed to the joint, and makes the tube difficult to cut. Because. In addition, when the radially outer insertion portion is configured by the outer inclined surface and the radially inner insertion portion is configured by the inner inclined surface, the angle formed by the outer inclined surface and the inner inclined surface in the axial sectional shape Of these, the smaller angle is preferably 80 degrees or more, and more preferably 90 degrees or more in a state where no force is applied without being connected and fixed. This is to prevent the tip shape of the boundary portion of the tube connecting portion from being too sharp. In addition, in the case where the ring described later has an inclined surface on the main body side and radially inward, and the tube connecting portion has an outer inclined surface, the inclination of the inclined surface of the ring in the axial sectional shape The difference between the angle and the inclination angle of the outer inclined surface of the tube connecting portion is preferably less than 10 degrees, and more preferably matches.

  Moreover, it is preferable that the diameter of the circle formed by the boundary portion of the tube connecting portion is smaller than the outer diameter of the tube and larger than the inner diameter of the tube. As a result, in a state where the tube is connected and fixed to the joint, the tube connecting portion of the main body can be prevented from falling down radially inward, and resistance to fluid flow can be prevented, and the tube is cut. It can be difficult.

  The outer diameter of the tube connecting portion of the main body is preferably 1.05 times or more and 1.10 times or less the outer diameter of the tube in a state where the tube is not connected and fixed and no force is applied.

  The thickness in the radial direction of the tube connecting portion of the main body is preferably 1.5 times or more and 1.8 times or less the thickness of the tube in a state where the tube is not connected and fixed and no force is applied.

  The main body may be composed of a plurality of parts, but is preferably composed of one kind of resin composition. The resin constituting the main body is also preferably a resin having chemical resistance like the tube. Examples of such a resin include PTFE (polytetrafluoroethylene) or PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer). The melting point determined by determining the peak top by DSC (differential scanning calorimetry) of this resin is preferably 320 ° C. or higher and 330 ° C. or lower, and more preferably 327 ° C. Here, although not particularly limited, for example, the raw material of the PTFE molded product is compressed and solidified in a mold after powdery PTFE raw material powder is fired in a hot air environment furnace of 360 ° C. or higher and 380 ° C. or lower. However, if the raw material powder is not sufficiently fired under heating at this time, the melting point is higher than 327 ° C. and the mechanical properties are inferior. Cause. Moreover, it is preferable that the elasticity modulus measured based on ASTM D638 of this resin is 400 MPa or more and 800 MPa or less.

  In addition, it is preferable that the surface roughness of a main body is 0.001 or more and 2.0 or less. In addition, the measurement of the surface roughness here measured the surface of the radial direction outer side insertion part located in the front-end | tip of the tube connection part of a main body so that it may follow a substantially axial direction instead of the circumferential direction. The surface roughness here is measured using the SURFTEST SV-600 manufactured by Mitutoyo as the arithmetic average roughness Ra (μm) on the surface of the radially outer insert in accordance with JIS B0601-1994. did.

(4) Nut The nut has a nut thread portion, a reduced diameter portion, and a contacted portion.

  The nut thread portion is configured to be able to be screwed with the main body thread portion in a state where the tube connecting portion of the main body is inserted from one axial end side (opening opening side) to the other axial end side. Has been.

  The reduced diameter portion is provided on the other end side in the axial direction (the side opposite to the insertion opening side), and is configured such that the inner diameter is smaller than the nut thread portion.

  The contacted portion is formed so as to face one end side (opening opening side) in the axial direction with respect to the reduced diameter portion. The abutted portion is a portion of the entire nut that abuts a part of the ring in a state where the tube is connected and fixed to the joint.

  The nut is preferably configured so that the radial thickness at the end on the insertion opening side in the axial direction is thicker than the portion in the vicinity thereof.

  In the axial direction, the nut is preferably provided with a nut cylindrical portion that is not provided with a screw thread and extends in the axial direction between the nut screw thread portion and the reduced diameter portion. The radial thickness of the nut cylindrical part of the nut is such that the ring itself is deformed so that the tube will not come out even when the ring, which will be described later, is expanded beyond the elastic state and the outer diameter part of the ring is in contact with the nut. Is preferably 1.5 times to 4.0 times the thickness of the tube, and more preferably 2.5 times to 3.5 times.

  The nut may have a nut operation portion whose outer peripheral shape is a polygonal shape or a deformed shape when viewed in the axial direction. A nut operation part is a part pinched | interposed by a wrench or a human finger, when screwing a nut in a main body.

  The shape of the abutted portion is not particularly limited, but it is preferably a shape corresponding to a part of the abutting ring in a state where the tube is connected and fixed to the joint. For example, if the shape of a part of the ring that abuts in a state where the tube is connected and fixed to the joint is a surface shape, and the normal direction of the surface is the axial direction, the abutted portion is also a surface shape. The normal direction of the surface is preferably the axial direction.

  It is preferable that the nut is comprised with one type of resin composition. The resin constituting the nut is also preferably a resin having chemical resistance like the tube and the main body. Examples of such resins include PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer), PCTFE (polychlorotrifluoroethylene), PVDF (polyvinylidene fluoride), ETFE (tetrafluoroethylene / ethylene copolymer). Coalesced), PPS (polyphenylene sulfide), and mixtures thereof. Especially, it is preferable that it is comprised by PFA. The melting point determined by determining the peak top by DSC (differential scanning calorimetry) of this resin is preferably 295 ° C. or higher and 310 ° C. or lower. Since PFA having a melting point of 295 ° C. or higher is not too soft, deformation can be suppressed and the tube can be prevented from coming off. Further, PFA having a melting point of 310 ° C. or lower is excellent in cracking resistance and is not easily cracked. The elastic modulus of the resin measured according to ASTM D638 is preferably 400 MPa or more and 800 MPa or less.

  The nut is preferably transparent or translucent from the viewpoint that it can be visually confirmed whether or not the ring is located inside (the ring is not forgotten to be attached) in a state where the tube is connected and fixed to the joint. .

(5) Ring The ring is an annular member that is disposed in a space radially inward of the nut thread portion of the nut, has a higher elastic modulus than the tube, and is used so as to contact the contacted portion of the nut. As long as at least one ring is used in the joint, a plurality of rings may be used. When a plurality of rings are used, the ring that comes into contact with the contacted portion of the nut may be different from the ring that comes into contact with the outer surface of the tube.

  In a state where the main body, the nut and the ring are connected to the tube, the ring has an elastic modulus capable of realizing the following properties. That is, when the ring is in the elastic region, the tube can push the tube from the radially outer side to the radially inner side by its own stress. Moreover, when the ring is beyond the elastic region, the expanded ring is pushed radially inward by the radially inner surface of the nut, thereby pushing the tube from the radially outer side to the radially inner side. Can do. By adjusting the elastic modulus of the ring so that it is higher than the elastic modulus of the tube, the ring can be moved radially outward while a part of the tube is sandwiched between the ring and the end of the tube connecting part of the body. It can be elastically deformed so as to spread, and an elastic force can be applied to press the tube from the radially outer side to the radially inner side. Thereby, it is possible to firmly fix the tube, make it difficult to pull out the tube, and suppress the leakage of fluid passing through the inside of the tube. Even when some external force is applied to the tube with the nut screwed onto the main body and the joint fixed to the tube, the elastic modulus of the ring is adjusted as described above. Can be made difficult to escape. In addition, when some external force is further applied to the tube in a state where the joint is fixed to the tube, the ring can be deformed so as to further expand and exceed the elastic region. Thereby, it can suppress that a tube will be cut | disconnected by being clamped too much. Even when the ring expands and deforms beyond the elastic region in this way, the expanded ring has a radially outer portion in contact with the radially inner surface of the nut, It is pushed radially inward by the inner peripheral part. In this way, the ring pressed radially inward by the nut can be fastened and fixed by pressing the tube from the radially outer side toward the radially inner side, making it difficult to pull out the tube and passing through the inside of the tube The leakage of fluid can be suppressed.

  Further, since the ring is used as a member different from the nut, the nut rotates around the tube at the stage of screwing the nut onto the main body, but the rotation of the ring is suppressed. Thereby, it is possible to suppress the outer periphery of the tube from being damaged by the rotation of the ring and to protect the tube from cutting.

  As for the shape of the ring, the shape of the cut surface with the circumferential direction as the normal direction is a rectangular shape, or a shape that is at least radially inward and has a chamfered or rounded portion on the main body side in the axial direction It is preferable that The chamfered or rounded portion of the ring on the radially inner side of the ring is a portion that is 0.3% or more and 40% or less of the radial width of the ring. It is preferably a portion that is 1% or more and 40% or less of the axial width of the ring, is a portion that is 3% or more and 29% or less of the radial width of the ring, and is 2% or more of the axial width of the ring. It is more preferably a portion of 25% or less, a portion of 3% or more and 10% or less of the radial width of the ring, and a portion of 2% or more and 10% or less of the axial width of the ring. preferable. This range is preferable for the following reasons. That is, in a state where the joint is connected and fixed to the tube, the ring comes into contact with the tube at a portion on the radially inner side of the ring and on the main body side in the axial direction. In this joint, when a chamfered shape or a rounded shape is adopted in the portion on the radially inner side of the ring and on the main body side in the axial direction (the width of the ring in the radial direction). 0.3% or more and when it is used in a part of 1% or more of the axial width of the ring), even if a ring with a higher elastic modulus than the tube is adopted, It is possible to make it difficult for a local pressing force to act on the tube. Thereby, it is possible to suppress the cutting of the tube. In addition, a portion where the chamfered or rounded shape of the ring is adopted is a portion which is 40% or less of the radial width of the ring and 40% or less of the axial width of the ring. Therefore, since the contact area with the outer surface of the tube can be prevented from being too wide, it is possible to suppress the force that the tube is pressed by the ring from being dispersed and the tube from being easily pulled out. . In particular, the chamfered or rounded portion at the radially inner side of the ring and the portion on the main body side in the axial direction is a portion of 3% to 29% of the radial width of the ring, If it is a portion of 2% or more and 25% or less of the axial width of the ring, the tensile strength can be secured by biting the ring into the tube while further reducing the possibility of the tube being cut. It becomes possible.

  Moreover, since the tube is attached in a state inclined with respect to the axial direction so as to be along the outer surface of the radially outer insertion portion of the main body, among the portions on the main body side in the axial direction on the radial inner side of the ring, Portions other than the chamfered or rounded portion are pressed against the tube toward the direction of decreasing the tube thickness against the portion of the outer surface of the tube inclined with respect to the axial direction. On the other hand, the radially outer insertion portion of the main body is pressed against the tube toward the direction of reducing the thickness of the tube against the portion of the inner surface of the tube that is inclined with respect to the axial direction. Thereby, the tube is clamped by the portion on the radially inner side of the ring in the axial direction on the main body side and the radially outer side insertion portion of the main body. The portion where the tube is sandwiched is thinner than the other portion of the tube. In addition, the portion deeper than the portion where the tube is held is thicker than the portion where the tube is held. As a result, it is difficult for the thick part of the tube to pass through the part radially inward of the ring and sandwiched between the part on the axial body side and the radially outer insertion part of the body. It is possible to make it difficult to pull out.

  In addition, when the chamfered shape is formed on the ring, the smaller one of the angles formed by the normal of the chamfered surface and the radial direction of the ring is 20 degrees or more and 70 degrees or less. It is preferable that it is 30 degrees or more and 60 degrees or less, and it is especially preferable that it is 45 degrees.

  The outer diameter of the ring should be such that when the ring is expanded by being pushed outward in the radial direction, the inner diameter of the ring is in contact with the inner side of the nut without exceeding the elastic region. Specifically, it is preferably 85.0% or more and 99.9% or less, and more preferably 98.0% or more and 99.9% or less, of the inner diameter of the nut cylindrical portion of the nut. Further, the gap formed between the portion where the outer diameter of the ring is the longest and the inner diameter of the nut cylindrical portion of the nut is 0.1 mm or more in a state where no force is applied without being connected and fixed. It is preferably 0 mm or less, and more preferably 0.2 mm or more and 1.0 mm or less.

  The inner diameter of the ring is preferably 1.001 times or more and 1.04 times or less of the outer diameter of the tube, and more preferably 1.001 times or more and 1.01 times or less of the outer diameter of the tube.

  The radial thickness of the ring is preferably thicker than the tube. Specifically, the radial thickness of the ring is preferably 1.2 times or more and 2.5 times or less of the tube thickness, and 1.2 times or more and 2.0 times or less of the tube thickness. Is more preferably 1.4 times or more and 1.8 times or less.

  The axial width of the ring is not particularly limited, but for example, it is preferably 0.5 to 4 times the thickness in the radial direction of the ring, and preferably 1.0 to 2.0 times. More preferred.

  The ring is preferably composed of a single resin composition. The resin constituting the ring is also preferably a resin having chemical resistance like the tube, the main body, and the nut. Examples of such resins include PVDF (polyvinylidene fluoride), PCTFE (polychlorotrifluoroethylene), ETFE (tetrafluoroethylene / ethylene copolymer), PPS (polyphenylene sulfide), and mixtures thereof. It is done. These resin compositions may contain fillers, but preferably do not contain glass fibers. Among these resins, PVDF or PCTFE is preferable. The melting point determined by determining the peak top by DSC (differential scanning calorimetry) of this resin is preferably 130 ° C. or higher and 290 ° C. or lower, and more preferably 160 ° C. or higher and 230 ° C. or lower. If the melting point is within this range, the ring is not too soft, so that deformation can be suppressed, the tube can be made difficult to pull out, and cracking is less likely to occur due to excellent cracking resistance. The elastic modulus of the resin measured according to ASTM D638 is preferably 500 MPa or more and 4000 MPa or less, more preferably higher than the elastic modulus of the nut, more preferably higher than the elastic modulus of the tube, More preferably, it is 1000 MPa or more and 2500 MPa or less.

  When the elastic modulus of the nut is lower than the elastic modulus of the ring, the outer periphery of the ring is deformed so that it exceeds the elastic region in a state where the joint is connected and fixed to the tube, and the outer peripheral portion of the ring becomes the inner peripheral portion of the nut Even if it is in a state where it is pressed against the inner side in the radial direction, the height of the elastic modulus of the nut is not as high as the elastic modulus of the ring, so that the tube is overtightened This can prevent the tube from being cut.

  When the nut is transparent or translucent, the ring is preferably opaque or colored from the viewpoint of preventing forgetting to attach the ring.

  The surface roughness of the ring is preferably 0.001 or more and 8.0 or less. The surface roughness here is measured so that the surface of the portion of the ring that is located closest to the radially outer insertion portion of the main body in the connected and fixed state is not in the circumferential direction but in the substantially axial direction. Measured. The surface roughness here was measured as the arithmetic average roughness Ra (μm) on the surface of the above part of the ring using Mitutoyo SURFTEST SV-600 and conforming to JIS B0601-1994. .

(6) Relationship between members The relationship between the materials constituting each member, that is, as a combination of the resin constituting the tube and the resin constituting the ring and the resin constituting the nut, the resin constituting the tube is PFA, It is particularly preferable that the resin constituting the ring is PVDF or PCTFE, and the resin constituting the nut is PFA. In this combination, the resin constituting the main body is particularly preferably PTFE or PFA.

  Also, the relationship between the shape and size of each member, that is, when the ring is in the elastic region with the main body, nut and ring connected to the tube, the ring of the inner peripheral portion of the nut When the inner diameter of the portion located radially outward with respect to the portion having the largest outer diameter is X and the outer diameter of the portion having the largest outer diameter is Y, the nut and the ring are connected. The value of the formula (XY) / Y expressed by the length of the portion corresponding to X and Y in a state where no force is applied is preferably 0.003 or more and 0.020 or less, It is more preferably 0.0055 or more and 0.0121 or less, and further preferably 0.0055 or more and 0.0090 or less.

  Further, the relationship between the shape and size of each member, that is, when the ring is in the elastic region with the main body, the nut and the ring connected to the tube, of the inner peripheral portion of the nut, the ring In the case where the inner diameter of the portion located radially outside the portion having the largest outer diameter is X, the outer diameter of the portion having the largest outer diameter of the ring is Y, and the thickness of the tube is Z, The value of the formula (XY) / Z expressed by the length of the portion corresponding to X, Y and Z in a state where the nut, ring, and tube are not connected to each other and no force is applied, It is preferably 0.04 or more and 0.30 or less, and more preferably 0.05 or more and 0.25 or less.

  FIG. 1 is an exploded perspective view showing an outline of the appearance of the joint and the joint assembly according to the first embodiment.

  The joint assembly 150 is configured by coupling and fixing the joint 100 to the tube 90.

  The joint 100 includes the main body 20, a ring 70, and a nut 30.

  The tube 90 is radially inward of the nut 30 by screwing the nut 30 into the main body 20 in a state where one end of the tube 90 is connected to a tube connecting portion 22 (described later) of the main body 20. They are connected and fixed by being sandwiched between a ring 70 located on the radially outer side of the tube 90 and a tube insertion end 21 (described later) of the main body 20.

  Hereinafter, each member will be described in detail.

(Tube 90)
The tube 90 was made of PFA resin, and had an outer diameter of 57.4 mm, an inner diameter of 50.8 mm, and a radial thickness of 3.3 mm. The bending radius of the tube 90 was 0.91 m, and the elastic modulus of the tube 90 was 450 MPa.

(Main unit 20)
As shown in the side view external view of FIG. 2, the main body 20 includes a tube insertion end 21, a tube connecting portion 22, a main body screw thread portion 23, a main body operation portion 24, an attachment side screw thread portion 25, and a through hole 26. I have. The tube insertion end 21 constitutes the distal end on the side where the tube 90 is inserted. 2, the tube insertion end 21 includes an outer inclined surface 21a configured so that a radially outer portion is positioned radially inward as it extends outward in the axial direction, and an axially outer side. The inner inclined surface 21b is configured such that the radially inner portion is positioned radially outward as it goes. The tube connecting portion 22 is a portion where the inner surface of the tube 90 is in contact with the outer surface in a state where the tube 90 is inserted, and is configured to extend from the tube insertion end 21 in a cylindrical shape. The main body thread portion 23 is provided on the side opposite to the tube insertion end 21 side with respect to the tube connecting portion 22, and has an outer diameter larger than the outer diameter of the tube connecting portion 22. It is configured to be screwed with the mountain portion 34. The main body operation unit 24 is a portion that is clamped by a wrench or a human finger when the nut 30 is screwed into the main body 20, and is provided on the side opposite to the tube coupling unit 22 side with respect to the main body screw thread portion 23. . As shown in the top view in the axial direction of FIG. 4, the main body operation unit 24 has a shape in which each side of the rectangle is gently connected when viewed in the axial direction. The attachment-side screw thread portion 25 has a screw thread for being screwed to an attachment object (not shown). The through hole 26 is a hole that penetrates the main body 20 in the axial direction.

  As shown in FIG. 2, regarding the length in the axial direction, the total length a1 of the tube insertion end 21 and the tube connecting portion 22 is 28.0 mm, and the length a2 of the main body thread portion 23 is 40.0 mm. The length a3 of the main body operation unit 24 was 20.0 mm, and the length a4 of the attachment-side screw thread portion 25 was 30.0 mm. As shown in FIG. 3, the inner diameter a5 of the through hole is 20.8 mm, the diameter a6 of the circle formed by the boundary between the outer inclined surface 21a and the inner inclined surface 21b is 54.8 mm, and the tube connection The outer diameter a7 of the part 22 was 61.8 mm, and all were located on the concentric circle. In the axial cross section, the inclination angle θ1 of the outer inclined surface 21a with respect to the axial direction was 45 degrees, and the inclination angle θ2 of the inner inclined surface 21b with respect to the axial direction was 45 degrees. In the axial section, the angle formed by the inclined surface of the outer inclined surface 21a and the inclined surface of the inner inclined surface 21b was 90 degrees. Moreover, as shown in FIG. 4, the space | interval a8 of the opposing surfaces of the main body operation part 24 was 80.0 mm.

  The main body 20 was made of PTFE.

  The elastic modulus of the main body 20 was 460 MPa.

(Ring 70)
As shown in FIG. 5, the ring 70 includes an inner surface 71, an outer surface 72, a first side surface 73, a second side surface 74, an inner first inclined surface 75, an outer first inclined surface 76, an outer second inclined surface 77, and This is an annular member having an inner second inclined surface 78.

  The inner surface 71 constitutes the innermost surface in the radial direction of the ring 70 by a surface extending in a cylindrical shape parallel to the axial direction. The outer surface 72 forms a radially outermost surface of the ring 70 by a surface extending in a cylindrical shape in parallel with the axial direction. The first side surface 73 is a circumferential surface whose normal direction is the axial direction, and constitutes one end side of the ring 70 in the axial direction. The second side surface 74 is a circumferential surface whose normal direction is the axial direction, and constitutes the other end side of the ring 70 in the axial direction. The inner first inclined surface 75 is an inclined surface that connects the inner surface 71 and the first side surface 73, and the inclined surface is formed so as to be positioned radially outward as it approaches the first side surface 73 side in the axial direction. . The outer first inclined surface 76 is an inclined surface connecting the outer surface 72 and the first side surface 73, and the inclined surface is formed so as to be positioned radially inward as it approaches the first side surface 73 side in the axial direction. . The outer second inclined surface 77 is an inclined surface that connects the outer surface 72 and the second side surface 74, and the inclined surface is formed so as to be positioned radially inward as it approaches the second side surface 74 side in the axial direction. . The inner second inclined surface 78 is an inclined surface that connects the inner surface 71 and the second side surface 74, and the inclined surface is formed so as to be positioned radially outward as it approaches the second side surface 74 side in the axial direction. .

  The ring 70 had an inner diameter b1 of 57.7 mm, an outer diameter b2 of 68.5 mm, and an axial thickness b3 of 8.0 mm. The inner first inclined surface 75, the outer first inclined surface 76, the outer second inclined surface 77, and the inner second inclined surface 78 are all smaller angles of the inclined angles of the inclined surface with respect to the axial direction. Was 45 degrees. In addition, the inner first inclined surface 75 and the inner second inclined surface 78 are both shaped and large so as to be generated by obliquely scraping a width of 0.3 mm in the axial direction and a width of 0.3 mm in the radial direction. (See b4 and b7 in FIG. 5). Each of the outer first inclined surface 76 and the outer second inclined surface 77 has a shape and a size that are generated by obliquely scraping off a width of 0.5 mm in the axial direction and a width of 0.5 mm in the radial direction. (See b5 and b6 in FIG. 5).

  The ring 70 has a symmetrical shape, and the same result can be obtained regardless of which axial direction is directed to the main body 20 side. Therefore, in the present embodiment, the first side surface 73 is set to the main body 20 side. An example of the case will be described. In this case, the portion that mainly contributes to the clamping of the tube 90 with the main body 20 is the inner first inclined surface 75. Here, the inclination angle of the inner first inclined surface 75 with respect to the axial direction is 45 degrees in common with the inclination angle of the outer inclined surface 21a of the main body 20 with respect to the axial direction.

  The ring 70 was made of PVDF.

  The elastic modulus of the ring 70 was 2200 MPa.

(Nut 30)
As shown in the side view external view of FIG. 6, the side view sectional view of FIG. 7, and the view seen from the reduced diameter portion side in the axial direction of FIG. 32, a nut operation portion 33, a nut screw thread portion 34, a nut cylindrical portion 35, a reduced diameter portion 36, a contacted portion 37, and a bending portion 38.

  The insertion end portion 31 constitutes an insertion-side tip when the nut 30 is inserted into the main body 20 and has a shape that slightly expands radially outward. The outer cylindrical portion 32 extends in a cylindrical shape in the axial direction. The nut operating portion 33 is a portion that is clamped by a wrench or a human finger when the nut 30 is screwed into the main body 20, and is formed on the side opposite to the insertion end portion 31 side in the axial direction with respect to the outer cylindrical portion 32. Has been. As shown in FIG. 8, the nut operation unit 33 is configured such that each corner of the hexagon is rounded when viewed in the axial direction. The nut thread portion 34 is formed inside the nut 30 so that the nut thread portion 34 can be screwed into the main body thread portion 23 from the radially outer side when the nut 30 is inserted into the main body 20 and screwed. This constitutes the insertion end 31 side. The reduced diameter portion 36 extends from the end opposite to the insertion end portion 31 side toward the insertion end portion 31 side, and forms a cylindrical portion inside the nut 30. The nut cylindrical portion 35 constitutes a cylindrical portion inside the nut 30 so as to connect the nut thread portion 34 and the reduced diameter portion 36 in the axial direction, and the diameter of the reduced diameter portion 36 in the radial direction. This is the outer side in the direction and the inner side in the radial direction of the nut thread 34. The abutted portion 37 is configured so that the end portion on the insertion end portion 31 side of the reduced diameter portion 36 and the end portion on the opposite side of the insertion end portion 31 side of the nut cylindrical portion 35 spread in the radial direction. It is comprised by the connected surface (facing the insertion end part 31 side). The curved portion 38 is an R-shaped portion provided at a portion where the end portion of the nut cylindrical portion 35 opposite to the insertion end portion 31 side and the contacted portion 37 are connected.

  As shown in FIG. 6, the nut 30 has an outer diameter c <b> 1 of the insertion end 31 of 95.0 mm, and a length c <b> 2 connecting the rounded shapes facing each other in the nut operation portion 33 is 90 0.0 mm. Further, as shown in FIG. 6, regarding the length in the axial direction, the length c3 of the insertion end portion 31 is 41.5 mm, the length c4 of the outer cylindrical portion 32 is 31.0 mm, and the nut operation portion The length c5 of 33 was 5.0 mm. Further, as shown in FIG. 7, the inner diameter c6 of the nut cylindrical portion 35 was 69.0 mm, and the inner diameter c7 of the reduced diameter portion 36 was 58.0 mm. Further, as shown in FIG. 6, regarding the length in the axial direction, the length c8 of the nut thread portion 34 is 34.0 mm, the length c9 of the nut cylindrical portion 35 is 32.5 mm, and the diameter is reduced. The length c10 of the part 36 was 11.0 mm. The radius of curvature of the curved portion 38 was 0.5 mm.

  The nut 30 was made of PFA.

  The elastic modulus of the nut 30 was 500 MPa.

(Coupling and fixing operation)
In this example, the main body 20, the ring 70 and the nut 30 were fixed to the tube 90 and the joint 100 was connected and fixed to the tube 90 in the following procedure.

  First, the distal end of the tube 90 to which the joint 100 is to be attached is inserted into the nut 30 via the reduced diameter portion 36 side, and further inserted into the ring 70, as shown in the side sectional view of FIG. It was.

  Next, the inner diameter of the distal end portion of the tube 90 to which the joint 100 is to be attached was heated and expanded to about the outer diameter of the tube connecting portion 22. And the tube connection part 22 of the main body 20 was inserted inside the front-end | tip of the expanded tube 90, and it was set as the state as shown in the side view sectional drawing of FIG. Note that the tip of the tube 90 was positioned within the axial width of the tube connecting portion 22.

  Thereafter, the nut 30 was moved closer to the main body 20 in the axial direction and moved to a portion where the main body screw thread portion 23 of the main body 20 and the nut screw thread portion 34 of the nut 30 started to be screwed together. At this time, the ring 70 moved toward the main body 20 in the axial direction by the second side surface 74 of the ring 70 contacting the contacted portion 37 of the nut 30 in the axial direction. And by rotating the nut 30 with respect to the main body 20, the nut 30 was screwed with respect to the main body 20 so that it might be in the state shown to sectional drawing of the side view of FIG. Here, the main body 20 and the tube 90 are generally integrated and do not rotate as the nut 30 rotates. In addition, since the nut 30 and the ring 70 are configured separately, even when the nut 30 rotates, the ring 70 basically follows the outer surface of the tube 90 in the axial direction. It only moves and the ring 70 does not rotate on the outer surface of the tube 90.

  As the operation of screwing the nut 30 into the main body 20 is continued, the inner first inclined surface 75 of the ring 70 comes into contact with a portion of the tube 90 located near the outer inclined surface 21a of the main body 20. . Further, as the operation of screwing the nut 30 into the main body 20 is continued, a portion of the tube 90 located in the vicinity of the outer inclined surface 21a of the main body 20 is axially moved by the inner first inclined surface 75 of the ring 70. Push toward the main body 20 side. At this time, the ring 70 has a reaction force that is pushed back from the portion of the tube 90 that is located near the outer inclined surface 21a of the main body 20 to the side opposite to the main body 20 side in the axial direction, and a radially outer side. Receives the power to expand. As a result, the ring 70 is elastically deformed and is in a state in the elastic region, whereby an elastic force is applied to a portion of the tube 90 located in the vicinity of the outer inclined surface 21a of the main body 20. Become. Then, when the tightening torque when tightening the nut 30 reaches a predetermined value of 250 kgf · cm, the operation of screwing the nut 30 into the main body 20 is finished, and the state shown in the side sectional view of FIG. Thus, the joint 100 was connected and fixed to the tube 90. The reason why the tightening torque is a value of 250 kgf · cm is based on the following reason. That is, when the shape, size, and material of the above embodiment are assumed, the sealing property can be improved (the fluid passing through the tube 90 does not leak) and the tensile strength can be improved (the tube 90). The lower limit of the value of the tightening torque was grasped from the viewpoint that the screw cannot be removed from the joint 100). Also, assuming the shape, dimensions, and material of the above embodiment, the tube connecting portion 22 of the main body 20 will not fall greatly inward in the radial direction due to excessive tightening and the flow path will not be greatly narrowed. From this point of view, we grasped the upper limit of the tightening torque value. An appropriate value for determining that the operation of screwing the nut 30 into the main body 20 has been completed is determined from the lower limit and upper limit ranges of the tightening torque thus obtained.

  Note that the end point of the screwing operation of the nut 30 into the main body 20 is a tightening distance corresponding to the above-described tightening torque value (a position where the outer surface of the nut 30 is located, a position where the outer surface of the main body 20 is located, It may be determined by predetermining the change in the distance.

(Consolidated and fixed state)
FIG. 13 shows an enlarged schematic cross-sectional view of the main part in a state where the joint 100 is connected and fixed to the tube 90.

  In the connected and fixed state, a gap in the radial direction is formed between the outer surface 72 constituting the radially outer side of the ring 70 and the inner surface of the nut cylindrical portion 35 of the nut 30 positioned on the radially outer side. Has occurred. That is, the radial distance B from the axial center to the inner surface of the nut cylindrical portion 35 of the nut 30 is longer than the radial distance A from the axial center to the outer surface 72 of the ring 70. This gap can be confirmed as follows, for example. That is, when a colored paint or the like is applied to the outer surface 72 constituting the radially outer side of the ring 70 in advance, the nut cylindrical portion 35 of the nut 30 is connected and fixed, and the nut 30 is removed from the connected and fixed state. By visually recognizing that the colored paint does not appear on the inner surface, it can be confirmed that a gap exists in the connected and fixed state. In the state of being connected and fixed, the radial distance C from the axial center to the boundary between the outer inclined surface 21 a and the inner inclined surface 21 b of the main body 20 is the radial distance from the axial center to the inner surface 71 of the ring 70. The boundary portion between the outer inclined surface 21a and the inner inclined surface 21b of the main body 20 is shorter than the distance D and is within the range of the radial thickness width of the tube 90 (the portion located on the radially inner side of the ring 70). Was located at.

  In this embodiment, the state where the tightening torque is reached is the state of being connected and fixed. However, when the shape, size, and material are different from those of this embodiment, the state of being connected and fixed is a different standard. You may specify. For example, as shown in FIG. 14, the axis between the position s in the axial direction of the first side surface 73 of the ring 70 and the position t in the axial direction of the boundary portion between the outer inclined surface 21 a and the inner inclined surface 21 b of the main body 20. The distance in the direction is within 30% of the thickness of the tube 90 in the radial direction (half of the difference between the outer diameter and the inner diameter when no force is applied) (minus 30% or more plus 30% or less). The state of being connected may be a state of being connected and fixed.

(External force is applied and the ring is expanded)
FIG. 15 shows an enlarged schematic cross-sectional view of a main part when an external force is further applied to the tube 90 in a state where the joint 100 is connected and fixed to the tube 90.

  Here, applying an external force was performed using a tensile tester used in a tensile performance evaluation test. Specifically, an external force was applied by pulling the tube 90 so that the tube 90 was separated from the joint 100 in the axial direction in a connected and fixed state. The tensile strength here was set to 15 MPa based on the shape, dimensions, and material of the above example. Here, the tensile speed was 200 mm / min. In the connected and fixed state, the thickness of the tube 90 is thin at the portion sandwiched between the inner first inclined surface 75 of the ring 70 and the outer inclined surface 21a of the main body 20, and the thickness before and after the thickness is reduced. Is getting thicker. For this reason, when the tube 90 is pulled in a direction away from the joint 100 in the axial direction by a tensile tester in a connected and fixed state, the ring 70 is moved radially outward by the portion of the tube 90 where the thickness is thick. It will be expanded. In this way, the ring 70 exceeds the elastic region, and the outer surface 72 constituting the radially outer side of the ring 70 comes into contact with the inner surface of the nut cylindrical portion 35 of the nut 30.

  In addition, the value of 15 MPa of the tensile strength as the external force described above is (i) the maximum stress due to the tube tension (value when the tube extends beyond the yield point) and (ii) the maximum stress due to the fluid pressure ( (Iii) based on the specification of the maximum working pressure of the tube 90) and (iii) the maximum stress due to tightening, and the situation where a tensile stress obtained by summing was applied.

  In a state where the ring 70 is expanded by further applying the above-described external force, the ring 70 is in a state exceeding the elastic region, and is located on the outer surface 72 constituting the radially outer side of the ring 70 and the radially outer side thereof. The inner surface of the nut cylindrical portion 35 of the nut 30 is in contact. In addition, about the outer surface 72 which comprises the radial direction outer side of the ring 70 contacting the inner surface of the nut cylindrical part 35 of the nut 30, as mentioned above, the outer surface 72 which comprises the radial direction outer side of the ring 70 is colored beforehand. When the nut 30 is removed after being connected and fixed in a state where paint is applied and an external force is applied by a tensile testing machine, the color of the colored paint is generated on the inner surface of the nut cylindrical portion 35 of the nut 30. It was confirmed by visually confirming that As a result, in a state where the ring 70 is expanded due to an external force, the ring 70 is radially inward from the nut 30 via a contact portion between the outer surface 72 of the ring 70 and the nut cylindrical portion 35 of the nut 30. It was confirmed that the pushing force was applied. For this reason, the ring 70 can be said to be able to press the tube 90 inward from the radially outer side.

(Evaluation)
About the sample in a state in which the above-described external force is not applied and the above-described sample in which the external force is applied and the sample in which the above-described external force is applied after being connected and fixed, an airtight performance evaluation test, a pressure resistance performance evaluation test, a thermal cycle performance Evaluation was performed by an evaluation test and a repeated bonding performance evaluation test.

In the airtightness performance evaluation test, one end is sealed, the entire joint 100 is immersed in water, N ₂ gas is filled into the tube 90, the internal pressure is increased to 1.4 MPa, and bubbles are generated after 5 minutes. This was done by visually confirming the presence or absence of. Here, the acceptance criterion was that there was no leakage of N ₂ gas (generation of bubbles) for 1 minute.

  In the pressure-resistant performance evaluation test, one end is sealed and a hand pump is connected. After filling the tube 90 with water, the hand pressure pump gradually increases the internal pressure to check for fitting leakage and tube 90 disconnection. It was done by checking. The acceptance criterion was that no leakage occurred until the tube 90 burst.

In the repeated bonding performance evaluation test, the attaching and detaching work of the tube 90 and the joint 100 was repeated 20 times, and thereafter, the same test method as the airtightness evaluation test was performed. Even after 20 repetitive attachment / detachment construction operations, the acceptance criterion was that there was no leakage of N ₂ gas (generation of bubbles) for 1 minute.

  Regarding the above evaluation test, both the sample in a state where the above-described external force is not applied and the sample in a state where the above-described external force is applied after being connected and fixed are both in any test. It was a pass.

(7) Other Embodiments As an example corresponding to the above-described embodiment, the above-described example has been given as an example. However, the embodiment is not limited thereto, and the following is obtained by appropriately changing the embodiment. It is good also as an embodiment.

(7-1)
In the example of the above-described embodiment, the case where the portion other than the reduced diameter portion 36 is configured by the nut thread portion 34 and the nut cylindrical portion 35 inside the nut 30 has been described as an example.

  However, the embodiment is not limited to this. For example, as shown in FIG. 16, instead of the nut 30 of the above embodiment, the nut thread portion 34 of the above embodiment is extended in the axial direction, and the above embodiment is performed. You may use the nut 230 provided even to the part corresponded to the nut cylindrical part 35 of an example.

(7-2)
In the example of the above embodiment, the case where only one ring 70 is used has been described as an example.

  However, the embodiment is not limited to this. For example, as shown in FIG. 17, the ring 70 and the ring 270 are pivoted by further using a ring 270 having the same shape and size as the ring 70 of the above embodiment. You may use it side by side so that it may continue in a direction.

DESCRIPTION OF SYMBOLS 20 Main body 22 Tube connection part 23 Main body thread part 30 Nut 34 Nut thread part 36 Reduced diameter part 37 Contact part 70 Ring 90 Tube 100 Joint 150 Joint assembly

JP 2009-144916 A

Claims (8)

A joint (100) connected to a tube (90) having at least an inner surface made of resin;
A tube connecting part (22) provided at one end and a main body thread part (23) provided on the outer peripheral surface so as to have an outer diameter larger than that of the tube connecting part, and extending in the axial direction A body (20) in which a hole (26) is formed;
A nut thread portion (34) that can be screwed with the main body thread portion in a state in which the tube connecting portion of the main body is inserted from one end side in the axial direction toward the other end side in the axial direction; A reduced diameter portion (36) having an inner diameter smaller than that of the nut thread portion, and a contacted portion formed so as to face one end side in the axial direction with respect to the reduced diameter portion. parts and (37), have a, a nut (30) is an elastic modulus equal to or less than 800MPa or more 400 MPa,
Disposed in said nut threaded portion radially inward of the space than the nut, higher elastic modulus than the tube, and abut against the abutted portion of the nut, the elastic modulus is less 2500MPa or more 1000MPa At least one ring (70);
With
When the ring is in an elastic region, a radial gap is provided between the outer peripheral portion of the ring and the inner peripheral portion of the nut located on the radially outer side of the ring. And
The ring is configured to exceed the elastic region at a stage before contacting the radially inner surface of the nut when the ring spreads radially outward.
In the state where the main body, the nut and the ring are connected to the tube,
When the ring is in an elastic region, the ring is pushing the tube from the radially outer side to the radially inner side by its own stress,
When the ring exceeds the elastic region, the expanded ring is pushed radially inward by the radially inner surface of the nut, so that the tube is directed radially outward from radially outward. The ring has an elastic modulus so that it can be pushed,
Fittings. The shape of the cross section in which the circumferential direction of the ring is a normal direction is a rectangular shape that is at least radially inward and has a chamfered or rounded shape on the main body side in the axial direction. And
The chamfered shape or the rounded portion in the axially inner portion of the ring is 0.3% or more and 40% or less of the radial width of the ring. A portion of 1% or more and 40% or less of the axial width of the ring,
The joint according to claim 1 . The chamfered shape or the rounded portion in the axially inner portion of the ring is a portion that is 3% or more and 29% or less of the radial width of the ring. And is a portion of 2% to 25% of the axial width of the ring,
The joint according to claim 2 . When the main body, the nut, and the ring are connected to the tube and the ring is in an elastic region, the outer diameter of the ring is the largest of the inner peripheral portion of the nut. Let X be the inner diameter of the part located radially outside the part,
When the outer diameter of the portion where the outer diameter of the ring is the maximum is Y,
About the length of the portion corresponding to X and Y in a state where the nut and the ring are not connected and no force is applied,
(XY) / Y
The value of is 0.003 or more and 0.020 or less,
The joint according to any one of claims 1 to 3 . When the main body, the nut, and the ring are connected to the tube and the ring is in an elastic region, the outer diameter of the ring is the largest of the inner peripheral portion of the nut. Let X be the inner diameter of the part located radially outside the part,
The outer diameter of the portion where the outer diameter of the ring is the maximum is Y,
In the case where the thickness of the tube is Z,
Said nut, said ring, and wherein in a state in which the tube is not any force acting not connected to each other X, the length of the portion corresponding to the Y and the Z,
(XY) / Z
The value of is 0.04 or more and 0.30 or less,
The joint according to any one of claims 1 to 4 . The tube is composed of a resin composition containing at least one selected from the group consisting of PFA, FEP and PTFE,
The nut is composed of a resin composition containing at least one selected from the group consisting of PFA, PCTFE, PVDF, ETFE, and PPS,
The ring is composed of a resin composition containing at least one selected from the group consisting of PCTFE, PVDF, ETFE, and PPS.
The joint according to any one of claims 1 to 5 . The ring is opaque and the nut is transparent or translucent;
The joint according to any one of claims 1 to 6 . Said tube (90);
A joint (100) according to any one of claims 1 to 7 ;
With
The tube is configured to include a resin having chemical resistance, and a bending radius is not less than 0.3 m and not more than 3.0 m.
Fitting assembly (150).

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