JP3978276B2 - Method for manufacturing hose fittings - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a hose fitting, and more particularly to a method for producing a hose fitting in which a cylindrical thin tube is not crushed when a hose insertion portion is caulked to connect a rubber hose.
[0002]
[Prior art and problems to be solved by the invention]
Conventionally, hose fittings have been used to connect hydraulic equipment and hoses. In a hydraulic brake for automobiles, a hose fitting shown in FIG. 1 is used. The hose fitting includes a bottomed cylindrical hose insertion portion (socket portion) 10 into which a rubber hose can be inserted and a through hole is formed in the bottom surface, and a through hole formed in the bottom surface of the hose insertion portion 10. Via a cylindrical inner tube (nipple) 12 provided in the hose insertion portion 10 so as to communicate with the cylindrical inner tube 12 and a hollow cylindrical shaft portion (neck portion) 14 provided so that the hollow portion communicates with the cylindrical inner tube 12. And a head (union bolt mounting portion) 16 connected to the hydraulic equipment.
[0003]
One end of the rubber hose is inserted into the hose insertion portion 10 so that the cylindrical inner tube 12 is inserted into the rubber hose, and the hose fitting is connected to the rubber hose by caulking the hose insertion portion 10.
[0004]
Conventionally, this hose fitting is manufactured as follows.
In the first method, as shown in FIG. 2A, a blank is manufactured by cold forging to the maximum diameter. Thereafter, as shown in FIG. 2 (B), the outer periphery of the shaft portion 14 and the head portion 16 is cut and a through hole having a diameter of 2.3 mm that penetrates the shaft portion 14 and the cylindrical inner tube 12 is formed by cutting. It is manufactured by performing two-side cutting, bolt hole cutting with a diameter of 10 mm, and deburring.
[0005]
In the second method, first, as shown in FIG. 3 (A), the hose insertion portion 10, the outer peripheral portion 12 ′ of the inner tube cylinder 12, and the portion 14 ′ corresponding to the outer peripheral portion of the shaft portion 14 are cold forged. To form. Thereafter, as shown in FIGS. 3B and 3C, the outer peripheral portion 16 ′ of the head portion 16 is processed in several steps, the through-hole penetrating the cylindrical inner tube 12 and the shaft portion 14, and the head 16. A through hole or the like is formed by cutting, and a hose fitting is manufactured as shown in FIG.
[0006]
However, in the first method and the second method, there are problems that the material is wasteful, the number of processing steps is large, the cutting cost is large, inefficient, the cost is high, and the quality is varied. was there.
[0007]
In order to solve the above problem, as shown in FIG. 4, the third method includes a hose insertion portion 10 having a shaft portion 14 integrally formed with a hose insertion portion 10 and a shaft portion 14, and a head. 16 is separately formed by cold forging, and the cylindrical inner tube 12 is separately formed by cutting. After these three parts are assembled, they are manufactured by brazing and welding with Cu in a furnace. .
[0008]
Further, in the fourth method, as shown in FIG. 5, the three portions of the hose insertion portion 10, the shaft portion 14, and the head portion 16 are integrally processed by cold forging, and the shaft portion 14 and the head portion 16 are processed. the through-holes are formed by cutting the further cutting separately to form a cylindrical inner tube 12, after assembling these two parts is prepared by brazing welding of Cu in a furnace, or cylindrical inner The tube 12 is manufactured by caulking the bottom surface of the hose insertion portion 10.
[0009]
However, the brazing method fittings of the third method and the fourth method are welded at a high temperature of 1120 ° C. in the furnace, so that the entire hose fitting is annealed and the hardness is lowered. Although the hardness of the hose insertion part decreases, there is an advantage that it is possible to prevent cracking and reduce the caulking load when the hose insertion part is caulked by inserting the rubber hose into the fitting, but the cylindrical inner tube is also annealed Since the hardness is lowered, when the hose insertion portion is caulked, the cylindrical inner tube may be crushed and the oil passage may be narrowed.
[0010]
In order to prevent caulking cracks and the like of the hose insertion portion, the hardness is required to be Hv 250 or less, and in order to prevent the tube in the cylinder from being crushed, the hardness of the tube in the cylinder must be guaranteed to be Hv 120. For this reason, the hose insertion part and the cylindrical inner pipe are simultaneously molded with the same material by cold forging, and the method of brazing and welding only the head to this simultaneously molded product is conventionally adopted because the hardness of the cylindrical inner pipe decreases. could not.
[0011]
For this reason, the hose insertion part and the cylindrical inner tube are formed separately, and the cylindrical inner tube is subjected to carburizing treatment before brazing to guarantee the hardness after brazing, or the material is chromium molybdenum steel, or Since expensive materials such as high carbon steel such as chromium steel and alloy steel are used, there is a problem that the cost increases.
[0012]
In addition, the metal fitting of the construction method that caulks the cylindrical tube by the fourth method needs to perform a liquid-tightness test to guarantee the liquid-tightness of the caulked portion, which requires a lot of man-hours for the quality test and costs. There is a problem of becoming high.
[0013]
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a hose fitting manufacturing method capable of manufacturing a brazing hose fitting at a low cost.
[0014]
[Means for Solving the Problems]
To achieve the above object, the invention of claim 1 comprises a hose insertion part into which a rubber hose is inserted, a cylindrical inner pipe provided in the hose insertion part, and a head connected to a hydraulic device, One end of a rubber hose is inserted into the hose insertion part so that the cylindrical inner tube is inserted into the rubber hose, and the hose mouth part that is connected to the rubber hose by caulking the hose insertion part is manufactured by a brazing method. A method of manufacturing a metal fitting, characterized in that brazing welding in a furnace is performed in a state where a cap made of high carbon steel is placed on the cylindrical inner tube.
[0015]
In the present invention, the hose insertion portion and the cylindrical inner tube can be manufactured separately, or the hose insertion portion and the cylindrical inner tube can be manufactured integrally by cold forging.
[0016]
When the hose insertion part and the cylindrical inner tube are manufactured separately, the cylindrical inner tube is manufactured using a material such as low-cost low carbon steel. By manufacturing separately in this way, it can manufacture efficiently at low cost compared with the conventional 1st method and 2nd method.
[0017]
In addition, when the hose insertion portion and the cylindrical inner tube are manufactured integrally by cold forging, the hose insertion portion and the cylindrical inner tube are manufactured using the same material such as low-cost low carbon steel, The head is manufactured separately.
[0018]
The hose insertion part and the cylindrical inner pipe, or the integrated part and head part of the hose insertion part and the cylindrical inner pipe integrated in the furnace with the cylindrical inner pipe covered with a cap made of high carbon steel. It is brazed and welded. In the furnace, carbon is released from the surface of the cap, and carbon penetrates into the cylindrical inner tube closest to the cap. This carburization phenomenon increases the carbon content of the steel surface constituting the cylindrical inner tube and increases the hardness. Raised, it can be formed to a hardness that can withstand the caulking force when connecting the rubber hose and the hose fitting. In addition, since the cap that has been used and has a small amount of carbon can be carburized again and reused, the processing cost of the cap with respect to the overall cost can be reduced to reduce the cost.
[0022]
In the first aspect of the invention, the hose insertion part is made of low carbon steel, and the hardness of the hose insertion part is reduced by brazing and welding, so the rubber hose is inserted into the fitting and the hose insertion part is caulked. The crack prevention and caulking load at the time can be reduced.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0024]
First, the first embodiment will be described. As described with reference to FIG. 4, the hose insertion portion 10 having the shaft portion 14 formed integrally with the hose insertion portion 10 and the shaft portion 14 and the head portion 16 are separately formed by cold forging and cylindrical. The inner tube 12 is separately formed by cutting or cold forging. The hose insertion part 10 provided with the shaft part 14, the head part 16, and the cylindrical inner tube 12 are formed of a material such as low carbon steel.
[0025]
Moreover, as shown to FIG. 6 (A), the bottomed cylindrical cap 20 is formed with high carbon steel with steel. The cap 20 is formed in a size that can be stored in the hose insertion portion 10 and that the cylindrical inner tube 12 can be stored in the cap 20.
[0026]
After assembling the three parts of the hose insertion portion 10 having the shaft portion 14 formed separately, the head portion 16 and the cylindrical inner tube 12 so as to be brazed, as shown in FIG. 12 is covered with a cap 20, inserted together in a furnace, and welded by brazing with Cu in the furnace to produce a hose fitting.
[0027]
The inside of the furnace becomes a high temperature of about 1120 ° C., and carbon is released from the surface of the cap from the time when the first transformation point occurs in the welding process due to the influence of the atmosphere in the furnace. Carbon invades. And when it leaves the furnace, the cylindrical inner tube 12 is entirely carburized by the carburizing phenomenon, and this carburizing increases the carbon content of the surface of the steel constituting the cylindrical inner tube, thereby increasing the hardness, and the rubber hose. It can be formed to a hardness that can withstand the caulking force when connecting the hose fitting to the hose.
[0028]
This cap may be obtained by carburizing low carbon steel, and a cap whose carbon content has been reduced after being used is carburized again and reused several times. Thereby, the processing cost of the cap with respect to the whole cost can be reduced, and cost can be reduced.
[0029]
As described with reference to FIG. 5, the three portions of the hose insertion portion 10, the shaft portion 14, and the head portion 16 are integrally formed by cold forging, and the through holes of the shaft portion 14 and the head portion 16 are formed. It is formed by cutting, and further, the inner tube 12 is formed by cutting or cold forging, and after these two parts are assembled, the cap 20 is put on the inner tube 12 and put together in the furnace. It may be inserted and brazed and welded with Cu in a furnace.
[0030]
Next, a second embodiment of the present invention will be described. The hose insertion portion 10 having the shaft portion 14 formed integrally with the hose insertion portion 10 and the shaft portion 14 and the head portion 16 are separately formed by cold forging and the cylindrical inner tube 12 is configured. The cylindrical tube 22 (see FIG. 7) is separately formed by cutting or cold forging. In addition, the hose insertion part 10 provided with the axial part 14, the head 16, and the cylindrical tube 22 are formed with materials, such as low carbon steel. Further, the outer diameter of the cylindrical tube 22 is processed to be large within a range that can be reduced by drawing with an open die (within 30% of the target dimension).
[0031]
After assembling the hose insertion part 10 with the shaft part 14 formed separately, the head part 16 and the cylindrical tube 22 so that they can be brazed, they are inserted together in a furnace and brazed with Cu in the furnace. Weld by attaching.
[0032]
After removal from the furnace, as shown in FIG. 7, a guide pin 26 is inserted into the cylindrical tube 22 to prevent the inner diameter of the cylindrical tube 22 from contracting, and the tip of the outer periphery of the cylindrical tube 22 is contracted. Reduction is performed so that the outer diameter of the cylindrical inner tube is obtained by drawing with the open die 24 having a diameter.
[0033]
In this way, flow is generated on the surface of the steel constituting the cylindrical tube due to reduction by drawing, the hardness of the steel surface constituting the cylindrical inner tube is increased, and the caulking force when connecting the rubber hose and the hose fittings It can be formed to a hardness that can withstand.
[0034]
In the above, the example of reducing the outer diameter of the cylindrical tube has been described, but the outer diameter of the cylindrical tube is formed to be approximately the same as the outer diameter of the inner tube, and the inner diameter of the cylindrical tube is reduced within a range that can be reduced, An inner cylinder tube may be formed by expanding the inner diameter of the cylinder tube. When expanding the inner diameter of the cylindrical tube, as shown in FIG. 8, a die including a pin 28 whose tip is enlarged and a die 30 having the same diameter from the tip to the base end is used.
[0035]
Further, the outer diameter of the cylindrical tube is larger than the outer diameter of the inner tube, and the inner diameter of the cylindrical tube is smaller than the inner diameter of the inner tube. May be performed simultaneously. In this case, a die may be configured by combining the die 24 shown in FIG. 7 and the pin 28 shown in FIG.
[0036]
Next, the third embodiment will be described. In each of the above embodiments, the example in which the cylindrical inner tube is processed separately has been described. However, as shown in FIG. 9, the hose insertion portion 10, the shaft portion 14, and the cylindrical inner tube 12 are integrally manufactured. At the same time, the head 16 is manufactured as a separate body, a cap is placed on the cylindrical inner tube 12, and the integrated part including the hose insertion portion, the shaft portion, and the cylindrical inner tube is brazed and welded with Cu in the furnace. Thus, the hardness of the inner tube is increased, or as described in the second embodiment, at least one of the reduction of the outer diameter of the cylindrical tube and the increase of the inner diameter of the cylindrical tube is performed. You may make it raise hardness.
[0037]
If the hose insertion part and the cylindrical inner pipe are processed with the same material, the hardness of the cylindrical inner pipe decreases, so it has been impossible in the past to process the hose insertion part and the cylindrical inner pipe with the same material. As shown in Fig. 9, the hose insertion part and the cylindrical inner tube can be processed with the same material by using a method in which the head is assembled into an integral part and then brazed and welded, and only the cylindrical inner pipe is increased in hardness. It becomes possible.
[0038]
【The invention's effect】
As described above, according to the first aspect of the present invention, there is an effect that a hose fitting with a high hardness of the cylindrical inner tube can be manufactured using low-cost low-carbon steel.
[Brief description of the drawings]
1A and 1B are partial cross-sectional views showing a hose fitting. FIG.
2A and 2B are partial cross-sectional views for explaining a first conventional method for manufacturing a hose fitting. FIG.
FIGS. 3A to 3D are partial cross-sectional views for explaining a second conventional manufacturing method of a hose fitting. FIGS.
FIG. 4 is a partial cross-sectional view for explaining a third conventional manufacturing method of a hose fitting.
FIG. 5 is a partial cross-sectional view for explaining a conventional fourth manufacturing method of a hose fitting.
6A is a perspective view of a cap used in the first embodiment of the present invention, and FIG. 6B is a cross-sectional view showing a state where the cap is put on.
FIG. 7 is a cross-sectional view for explaining drawing processing according to the second embodiment of the present invention.
FIG. 8 is a cross-sectional view showing another die used in the second embodiment of the present invention.
FIG. 9 is a cross-sectional view of a hose fitting according to a third embodiment of the present invention.
[Explanation of symbols]
10 Hose insertion part 12 Inner inner pipe 14 Shaft part

Claims (1)

A hose insertion portion into which a rubber hose is inserted, a cylindrical inner tube provided in the hose insertion portion, and a head connected to a hydraulic device, and the rubber hose is inserted so that the cylindrical inner tube is inserted into the rubber hose. One end is inserted into the hose insertion part, the hose insertion part is caulked and connected to a rubber hose.
A method for manufacturing a hose fitting, comprising brazing and welding in a furnace in a state where a cap made of high carbon steel is placed on the cylindrical inner tube.

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