JP4442806B2 - Anti-corrosion connection structure for metal pipes - Google Patents

Description

  The present invention relates to an inner circumference for supplying a target part with a liquid fuel such as gasoline and light oil, a gaseous fuel such as propane and natural gas, and a fluid such as brake oil and compressed air in automobiles and general industrial machines and devices. This is related to the connection structure of the resin-coated tube to the surface. Specifically, it is a metal tube with excellent sealing properties that is used to stably supply fluids containing corrosive substances, chlorofluorocarbons with various molecular structures, and various gases. The present invention relates to an anticorrosion connection structure.

  As a means for supplying fluids such as fuel, various oils and compressed air in automobiles, various industrial machines and devices, etc., it is used by connecting a relatively thin and thin metal pipe to its target part (for example, Patent Document 1). This thin and thin metal tube (hereinafter sometimes referred to simply as “metal tube”) has a certain mechanical strength and is excellent in workability, so it has a complicated and narrow structure, such as automobiles and movable heavy machinery. It is widely adopted as a fluid supply means using the underfloor of the like. However, for example, when the metal tube is disposed under the floor of an automobile or the like, it rusts by being exposed to the outside air for a long period of time, or is deformed because it is thin due to the impact of flying stepping stones, In some cases, there is a concern of damage.

  Therefore, in order to protect this thin and thin metal pipe, a method of protecting the outer peripheral surface of the metal pipe with a resin layer (for example, see Patent Document 2) has been proposed. In the prior art, as a means for connecting a thin and thin metal tube whose outer peripheral surface is coated with a resin to a connection target member, a so-called flare portion in which an end portion of the metal tube is expanded from an axial center in an outer peripheral direction is provided. A method is provided in which the front surface of the flare portion is brought into contact with the connection portion of the connection target member, and then pressed in the axial direction by a fixing nut to be screwed and fixed. However, there is a concern that when the resin coating layer and the fixing nut are in direct contact, the resin coating layer is broken and corrosion occurs in a thin metal tube having a small diameter. Therefore, in this proposal, when pressing the flare part, it is a technical solution to prevent the resin coating layer from being damaged by interposing a dedicated sleeve washer between the fixing nut and the flare part.

  On the other hand, in a thin and thin metal tube used as a means for supplying a fluid containing a corrosive substance, a coating layer made of resin, rubber, or the like is provided on the inner peripheral surface, and the end of the tube is formed using a conical punch. By expanding the tube to about 90 ° with respect to the shaft center, a single flare portion coated with resin or rubber is formed on the front surface, and the flare portion is brought into contact with a member to be connected as a sheet surface and pressed and joined. A method for protecting the metal tube has been widely adopted. However, when the seat surface is a single flare, its length is insufficient, it lacks elasticity for tightening with the fixing nut, leaks frequently due to imperfect sealing, and absorbs slip caused by twisting when tightening with the fixing nut. There was a problem that the protective film made of resin, rubber or the like peeled off.

Therefore, the end of the metal tube in which the tube made of resin material or rubber material is tightly fitted is expanded from the axial center to the outer peripheral direction, the tube from the expanded neck portion to the end is deleted, and the tip of the metal tube from which the tube has been deleted A portion is bent in the axial direction, and a front surface thereof is used as a sheet surface to a connection target member, and a flare portion having a double structure is formed by sandwiching an end portion of the tube inside the bent portion. Disclosed is a thin-walled thin metal pipe connection structure that extends from the bottom of the head neck that opens to the position of the circular pipe wall, and is configured as a thin cylindrical wall that presses and contacts the inner wall of the tube. (For example, refer to Patent Document 3). However, in the above means, the contact portion with the member to be connected, that is, the sheet surface is made of metal, so that the outer peripheral surface of the metal tube has a sealing performance as it is, which may cause leakage without securing sufficient airtightness, It was a source of corrosion.
Jikosho 61-26703 (1st-2nd page, 1st-4th figure) Japanese Utility Model Publication 61-191589 (1st page, Fig. 1 and 2) Jokosho 63-40711 (1st-3rd page, 1st-2nd figure)

  In each of the above-mentioned means as a connection structure for thin-walled thin metal pipes in the technical field, many excellent methods have been proposed as protection means against corrosion and impact from the outside of the metal pipe, and have already been put into practical use. However, unresolved issues remain with regard to the connection structure of metal pipes that ensure sealing performance against liquids and gases with small molecular structures such as chlorofluorocarbons and also have corrosion resistance against fluids containing corrosive substances. It was the actual situation. The present invention aims to solve such a problem, and coats the inner peripheral surface of a metal tube with a corrosion-resistant protective coating, and also contacts the metal surface with the fluid at the contact surface with the connection target member. The present invention is intended to provide a thin and thin metal pipe connection structure that can ensure excellent sealing performance despite the fact that the pressing force against the sheet surface is small.

  In the present invention for solving the above-mentioned problems, the inner peripheral surface is coated with resin or rubber, and the end of the two-layered metal tube is expanded in the outer peripheral direction, and then the expanded end is made to the axis. A double-structure pressing seat surface expanded from the axial center to the outer peripheral direction at the end of the metal tube by bending until the end of the bent metal tube is further bent around the end of the bent metal tube. And a tube body having a sheet surface coated with a resin or rubber coating on the entire surface of the terminal including the pressing seat surface, and the pressing seat surface is brought into contact with the pressure receiving seat surface of the connection target member The gist of the present invention is a metal tube anticorrosion connection structure characterized by comprising a fixing nut for screwing and fixing.

  According to the present invention, in the end of the metal tube, a terminal including a pressing seat surface having a double structure having a sheet surface coated with resin or rubber is 90 to 180 ° with respect to the axis of the metal tube. It is in the anticorrosion connection structure of a metal tube, which is formed by being expanded.

  The present invention is further characterized in that, in the end of the metal tube, a terminal including a double structure pressing seat surface having a sheet surface coated with resin or rubber is formed in a curled shape. The anticorrosion connection structure.

  In the anticorrosion connection structure of the metal tube according to the present invention, the pressing portion shape of the fixing nut is provided on the end of the metal tube and has a double structure pressing seat surface having a sheet surface coated with resin or rubber, It is preferable to form it so as to correspond to the back surface shape.

  Further, in the anticorrosion connection structure of the metal pipe according to the present invention, at the end of the metal pipe, a terminal including a double structure pressing seat surface having a sheet surface coated with resin or rubber, the fixing nut, It is a preferable aspect to interpose a sleeve washer as needed.

  According to the anticorrosion connection structure of a metal pipe according to the present invention, the sheet surface that comes into contact with the member to be joined is of course contacted with all fluids containing corrosive substances supplied by the metal pipe, that is, the inner peripheral surface of the metal pipe. Since the coating is made of resin, rubber, or the like, the metal tube is completely protected from the corrosive environment, and an excellent function in terms of anticorrosion is ensured. In addition, since the sheet surface that comes into contact with the connection target member is formed of an elastic member such as resin or rubber, excellent airtightness is secured, and particularly a fluid having a small molecular structure, such as a fluid such as chlorofluorocarbon, or a gas such as propane gas. Even so, it is possible to seal without leakage. Further, the connection structure according to the present invention is not only a pressing seat surface that contacts the member to be connected, but also a back surface that contacts the fixing nut, and is coated with a resin or rubber or the like, and has a double folded structure or a curl winding structure. As a result, the elasticity (friction) at the joint is further improved, sufficient airtightness is maintained even with a slight tightening force, and the structure of the fixing nut can be reduced in size and weight as much as possible. It has been confirmed that the economic effect is remarkable.

Embodiments of the present invention will be described below with reference to the accompanying drawings. However, the present invention is not limited to these embodiments, and can be freely modified within the scope of the gist of the present invention.
FIG. 1 is a cross-sectional view for explaining a processing procedure of a metal tube terminal in the anticorrosion connection structure of a metal tube of the present invention. FIG. 1 (a) shows the metal tube terminal at approximately 90 ° with respect to the axis in the first stage. (B) shows the expanded state in the second stage and expanded to 180 ° with respect to the axial center, and (c) shows that the end portion becomes a metal pipe in the third stage. FIG. 2 is a cross-sectional explanatory view showing an embodiment of the anticorrosion connection structure of the metal pipe of the present invention, and FIG. 3 is an anticorrosion connection structure of the metal pipe of the present invention. FIG. 4 is a sectional explanatory view showing still another embodiment of the metal pipe anticorrosion connection structure of the present invention.

  The anticorrosion connection structure for metal pipes according to the present invention is a connection structure for connecting relatively thin and thin metal pipes in order to supply various fluids to their target parts in automobiles and general industrial machines and devices. Various synthetic resins with excellent corrosion resistance on the inner peripheral surface of metal pipes, providing a connection structure for safely and reliably supplying highly corrosive fluids or liquids and gases with a small molecular structure to the target site. Alternatively, coating with rubber or the like is applied to at least one layer, preferably multiple layers, and the metal tube body has a two-layer structure having a corrosion-resistant coating on its inner wall, and then expanded, bent, further bent, or entangled with respect to the metal tube end, etc. As a result of this processing, a double-layer pressing seat surface is formed at the end of the metal tube, and the entire surface of the terminal including the pressing seat surface is coated with resin or rubber. A sheet surface with a coating is formed, and when connecting, the coating layer is connected as a sheet surface to protect the metal tube against corrosive fluid and to be sufficiently airtight against fluids and gases with a small molecular structure. It is a structural feature that can be maintained.

  According to the method for connecting a metal pipe in the present invention, after a pressing seat surface having a double structure having a sheet surface coated with resin or rubber is brought into contact with a pressure receiving seat surface of a connection target member, The fixing nut is externally fitted from the rear, and the connecting operation is completed by screwing and tightening the female screw formed on the connection target member while pressing the back surface of the pressing seat surface with the pressing portion. At this time, not only the seat surface that contacts the pressure receiving seat surface of the connection target member, but also the back surface of the pressing seat surface that contacts the pressing portion of the fixing nut is formed with a seat surface coated with resin or rubber. Therefore, the metal tube is completely protected from, for example, a fluid containing a corrosive substance, and the cushion effect of the double structure pressing seat surface is combined with the elastic effect provided by the coating layer, so that the fixing nut The tightening is reduced as much as possible, and the excellent step force acts as a spring washer that prevents the fixing nut from loosening, ensuring stable operation over a long period of time.

  The metal tube used in the present invention is a relatively thin and thin metal tube having a tube diameter of about 30 mm or less and a wall thickness of about 2 mm or less, and the type thereof is not particularly limited but has excellent ductility. The material is preferable, and it is appropriately selected according to its use such as normal steel, stainless steel, aluminum alloy or copper alloy, and may be an electric sewing tube or a seamless tube. For example, the corrosion-resistant film is configured to have a two-layer structure formed in at least one layer, preferably in a multilayer. Specifically, as shown in FIG. 1, a metal tube having a two-layer structure in which the inner peripheral surface of the tube body 1 and the anticorrosion coating 3 are coated is common. There are no particular limitations on the type and coating method of the corrosion-resistant film that is formed as long as it can withstand the intended purpose, and a conventionally known synthetic resin or the like may be coated by a known means.

In order to form a double pressing seat surface at the end of the metal tube having the above two-layer structure, a means for performing processing such as tube expansion, bending, bending, and entrainment may be used as long as the intended purpose can be achieved. Although not limited, normally, as shown in FIG. 1 (a), the end of the metal tube 2 is expanded by θ ₁ = 90 ° with respect to the axis of the metal tube using, for example, a conical punch or the like, and then As shown in FIG. 1 (b), the expanded portion is expanded to θ ₂ = 180 ° with respect to the axis between the metals using, for example, a press, and further as shown in FIG. 1 (c). The expanded end portion is bent using, for example, a bender or the like until a double structure parallel to the axis of the metal tube is obtained. The metal is further bent by a curling machine or the like around the end. 2 has a double-structured pressing seat surface expanded from the axial center of the metal tube in the outer peripheral direction, for example, a metal tube as shown in FIG. 2 or 3 is obtained, as shown in FIG. Provided for anticorrosion connection structure of metal tube.

  In the above processing procedure, when the second stage is shifted to the third stage, the expanded end portion is curled by, for example, drawing, for example, so that a metal tube having a terminal structure as shown in FIG. And is provided to the anticorrosion connection structure of the metal tube as shown in FIG.

  In the anticorrosion connection structure for a metal pipe according to the present invention, the fixing nut for screwing and fixing the pressing seat surface of the double structure formed at the end portion of the metal pipe to the pressure receiving seat surface of the connection target member is When the tip portion is formed at an angle of 90 °, for example, with respect to the shape of the back surface of the pressing seat surface, specifically, the axis of the metal tube as shown in FIG. It is desirable that the pressing portion has a shape. By being configured in this manner, each contact surface is flat and has a wide contact area without interposing a dedicated sleeve between the terminal including the double structure pressing seat surface and the fixing nut. As a result, a stable connection is maintained by uniform pressing, and the concern that the protective coating is damaged is also eliminated.

  In the present invention, it is also preferable that a sleeve washer that slides on the outer periphery of the metal tube is interposed between a terminal including a double-side pressing seat surface formed at the terminal of the metal tube and the fixing nut. However, when the metal tube is screwed and fixed to the connection target member, the sleeve absorbs the slip due to the torsion of the tip of the fixing nut to form the seat surface of the pressing seat surface from resin or rubber. In addition to guarding the protective coating, a more uniform pressing force is applied to the sheet surface, and a stable connection state over a long period is ensured.

An aluminum alloy tube having a wall thickness of 1.0 mm and a tube diameter of 10 mm was prepared, and an anticorrosion coating 3 was formed by coating polyvinyl fluoride on the inner peripheral surface thereof, thereby obtaining a metal tube 2 having a two-layer structure. Next, the end of the metal tube 2 is expanded and bent according to the procedures of FIGS. 1 (a), (b) and (c), and finally subjected to a bending process, as shown in FIG. The portion has a double-structured pressing seat surface 6 that is expanded 90 ° in the outer circumferential direction with respect to the axis of the metal tube 2, and the double-structured pressing seat surface 6 from the inner peripheral surface of the metal tube 2. A tube main body 1 having a corrosion protection coating made of polyvinyl fluoride was obtained over the entire surface of the terminal portion including. A metal nut according to the present invention as shown in FIG. 2 is fitted from the rear side of the obtained tube main body 1 by fitting a fixing nut 8 having a male screw formed on the outer periphery thereof to be screwed into the connection target member 5. The anti-corrosion connection structure was obtained. Note that the fixing nut 8 according to this example has a tip portion formed at a 90 ° inclination angle by matching the tip of the fixing nut 8 with the expansion angle of the double-layer pressing seat surface 6 of the metal tube body 1. Next, the pressure bearing surface 6 of the double structure of the metal tube main body 1 terminal part is brought into contact with the pressure receiving seat surface 7 of the connection target member 5, the fixing nut is slid forward, and the female screw of the connection target member 5 is As a result, the metal tube main body 1 and the connection target member 5 are brought into close contact with each other through the double-structure pressing seat surface 6 and the pressure receiving seat surface 7 and are fixed by the screwing portion 9. In this way, the connection state of the metal tube using the anticorrosion connection structure of the metal tube according to the present example as shown in FIG. 2 is completed, and the result of performing the leak test at a pressure of 20 kg / cm ² with nitrogen gas or compressed air. As a result, no leakage was observed, and it was confirmed that the product was sealed in a perfect condition.

  As shown in FIG. 3, the bending process is further advanced, so that the tube expansion angle of the double-structured press seat surface 6-1 is 180 ° with respect to the axis of the metal tube 2-1, Similarly, a metal pipe body 1-1 was formed, and a metal pipe anticorrosion connection structure was obtained in the same manner as in Example 1. Note that the fixing nut 8-1 in this example has a pressing portion shape at the tip thereof that is 180 ° perpendicular to the axis of the metal tube 2-1, that is, 180 ° as in the case of the pressing seat surface 6-1. Next, after completing the connection state of the metal pipe 2-1 as shown in FIG. 3, a leak test was performed in the same manner as in Example 1. As a result, no leak was found and it was confirmed that the tube was sealed in a perfect state. It was done.

  After completion of the second-stage tube expansion process in the first embodiment, the end of the metal tube 2-2 is curled by a drawing process using a curling machine to form a pressing seat surface 6-2 as shown in FIG. The anticorrosion joining structure of the metal tube was obtained in the same manner as in Example 1 except that the fixing nut 8-2 having the same pressing portion shape as that of the tip 2 was screwed. After completing the connection state of the metal tube 2-2 as shown in FIG. 4, a leak test was performed in the same manner as in Example 1. As a result, no leak was observed and a perfect seal state was confirmed. Needless to say, a cap nut such as JASO F 402 flare nut C (CN) may be used as the fixing nut.

  As described above in detail, according to the anticorrosion connection structure for metal pipes according to the present invention, the portions that come into contact with all fluids containing corrosive substances supplied by the metal pipes, that is, the inner peripheral surfaces of the metal pipes, of course, are to be joined. Since the sheet surface in contact with the member is entirely coated with resin or rubber, the metal tube is kept completely protected from the corrosive environment, and an excellent function in the anticorrosion surface is ensured. In addition, since the sheet surface that comes into contact with the connection target member is formed of an elastic member such as resin or rubber, excellent airtightness is secured, and particularly a fluid having a small molecular structure, such as a fluid such as chlorofluorocarbon, or a gas such as propane gas. Even so, it is possible to seal in a perfect state. Further, the connection structure according to the present invention is not only a pressing seat surface that contacts the member to be connected, but also a back surface that contacts the pressing portion of the fixing nut, and is coated with a resin or rubber, etc. Since it is formed in a wrapping structure, the elasticity (friction) at the joint is further improved, sufficient airtightness is maintained even with a slight tightening force, and the structure of the fixing nut can be made as small and light as possible. It has been confirmed that the economic effects brought about by it are also remarkable, and are expected to be widely used in the technical field.

It is sectional drawing for demonstrating the processing procedure of the metal pipe terminal in the anticorrosion connection structure of the metal pipe of this invention, (a) shows the 1st step, (b) shows the 2nd step, (c) Is the third stage. In the anticorrosion connection structure of the metal pipe of this invention, it is a cross-sectional explanatory drawing which shows the one Example. In the anticorrosion connection structure of the metal pipe of this invention, it is a cross-sectional explanatory drawing which shows another Example. In the anticorrosion connection structure of the metal pipe of this invention, it is a cross-sectional explanatory drawing which shows another Example.

Explanation of symbols

1, 1-1, 1-2 tube body 2, 2-1, 2-2 metal tube 3, 3-1, 3-2 coating layer 4, 4-1, 4-2 expanded portion 5, 5-1, 5-2 Connection target member 6, 6-1, 6-2 Pressing seat surface 7, 7-1, 7-2 Pressure receiving seat surface 8, 8-1, 8-2 Fixing nut 9, 9-1, 9-2 Threaded part

Claims (1)

The inner peripheral surface is coated with resin or rubber, and the end of the two-layered metal tube is expanded in the outer peripheral direction, and then bent until the expanded end portion becomes a double structure parallel to the axis, By further bending the bent end portion of the metal tube as a center, a double-structured pressing seat surface expanded from the axial center to the outer peripheral direction is formed at the end of the metal tube, and the end including the pressing seat surface A pipe body having a sheet surface coated with resin, rubber, or the like on the entire surface, and a fixing nut for abutting the pressing seat surface against the pressure receiving seat surface of the connection target member and screwing and fixing. And a terminal including a double-structured pressing seat surface having a sheet surface coated with the resin, rubber, or the like, is expanded or curled at 90 to 180 ° with respect to the axis of the metal tube. to become Te Anticorrosion connection structure of a metal tube, characterized.

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