JP3731300B2 - Manufacturing method of hose fitting, hose fitting and brake hose - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a hose fitting used for an industrial hose, a hose fitting produced by this production method, and a method for producing a brake hose for an automobile or the like using this hose fitting. It is.
[0002]
[Prior art]
Hose fittings are attached to the attachment end of the industrial hose in consideration of detachability, leakage prevention and reliability. This hose fitting is a head having a socket portion and a nipple portion located inwardly on one shaft end side on the hose side, and a screw portion on the other shaft end side. Is provided.
[0003]
As a method of manufacturing this kind of hose fitting, a method of forming each part by cutting, a method of separately manufacturing a main body part including a socket part and a head part and a nipple part and integrating them by brazing, or another There has been proposed a method of integrating the body portion and the nipple portion of the body by caulking (staking). Of these methods, the brazing method usually involves manufacturing the main body portion by plastic working such as a part former and cutting the nipple portion from a round bar or pipe material. Then, the nipple portion is press-fitted into the main body portion, and then brazed with a copper braze or the like.
[0004]
On the other hand, a method of forming the socket portion and the nipple portion by plastic working and finishing the rear head portion by machining is also conceivable.
[0005]
[Problems to be solved by the invention]
However, among the above-described conventional manufacturing methods, the method based on total cutting generates a large amount of chips, and is slow in operation speed and high in cost. In addition, there is a difficulty in lacking dimensional stability.
[0006]
Next, the brazing method is excellent in mass productivity, but the nipple part cutting process remains. In addition, processes such as press-fitting for brazing, copper ring insertion, alignment to a tray, brazing, copper brazing check after brazing, and the like are necessary, resulting in high costs. Further, the nipple portion is softened by brazing, which causes the nipple to be crushed during caulking. If brazing is not performed properly, there is a problem that fluid (oil) leakage may occur from the press-fitted location.
[0007]
Further, the caulking method has a shorter process than the brazing method, is less likely to cause nipple crushing, and is considered to have no problem in cost. However, since the risk of leakage from the caulking portion is considerably greater than that of brazing, it is a technique that is difficult to be used in practice.
[0008]
On the other hand, in the method of forming the socket part and the nipple part by plastic working, there is a risk that work hardening occurs in the intermediate product subjected to plastic working and ductility is lowered. Therefore, there is a possibility that the socket portion will be cracked when the socket portion of the fitting is crimped when the hose and the fitting are joined. Although stress relief annealing or annealing after plastic working seems to be effective to prevent cracking due to ductility loss due to work hardening, the product cost is increased due to the additional annealing process. Will increase.
[0009]
The present invention has been made in view of the above circumstances, and is capable of preventing fluid leakage, reducing costs, reducing dimensional stability, reducing chip processing, shortening processes, improving mass productivity, and maintaining strength of the nipple part, and also provides plastic working. A method of manufacturing a hose fitting that can reduce the product cost by reducing the heat treatment process, without causing cracks in the socket portion even if it is immediately crimped without performing a heat treatment such as annealing afterwards, An object of the present invention is to provide a hose fitting manufactured by this method and a brake hose using the hose fitting.
[0010]
[Means for Solving the Problems]
The manufacturing method of the hose fitting of the present invention has a socket part on one end side, a nipple part and an axial hole located inside the socket part , and a head part on the other end side, which are the same. A method for manufacturing a hose fitting that is integrally formed of a material, wherein a metal material having a drawing of 75% or more in a tensile test method (JIS Z 2241) of a metal material is used as a material for the hose fitting. The socket portion , the nipple portion, and the shaft hole are formed by a first process, and a second step of finishing the head portion by machining is provided.
[0011]
In addition, it is preferable that the hardness of the intermediate product after the said 1st process is Hv170-270 by the Vickers hardness in the state which does not heat-process, such as annealing.
[0012]
Hose inlet fitting of the present invention, the socket portion at one end, has a nipple portion and a shaft hole located inwardly of the socket part has a head at the other end, integral they are of the same material A metal hose fitting which is molded, and a metal material having a drawing of 75% or more in the tensile test method (JIS Z 2241) of the metal material is used as the material of the hose fitting. Part , the nipple part and the shaft hole are formed, and the head part is finished by machining.
[0013]
The brake hose of the present invention is characterized in that a hose fitting manufactured by the above manufacturing method is attached to an end portion of the hose.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a manufacturing method of a hose fitting according to an embodiment of the present invention and a hose fitting manufactured by this manufacturing method will be described with reference to the accompanying drawings.
[0015]
First, the structure of the manufactured hose fitting 1 will be described with reference to FIG. This hose fitting 1 has a socket portion 2 on one end side and a nipple portion 3 positioned radially inward of the socket portion 2, and a head 4 on the other end side and a screw formed on the inside thereof. Part 5. The socket part 2 and the head part 4 are integrally connected, and a brim part 12 is formed at the boundary position. The socket part 2 is formed in a tubular shape having an outer diameter and a length that can be appropriately fitted to the outer periphery of the hose end. The nipple portion 3 is formed in the shape of a small-diameter pipe that is coaxial with the socket portion 2 and has the same length, and is integrally formed with the shaft wall portion 6 that is formed inside the flange portion 12. A shaft hole 7 is formed coaxially in the nipple portion 3, and this shaft hole 7 passes through the shaft wall portion 6 and opens to the head 4 side. . A concave portion 8 is formed coaxially on the shaft end surface of the head 4, and a screw portion 5 made of a female screw is formed on the inner peripheral surface thereof. A conical seal portion 10 is formed on the bottom surface 9 of the recess 8, and a shaft hole 7 is opened at the axial center position. In addition, a groove 11 is formed on the outer peripheral surface of the head 4.
[0016]
Next, a method for manufacturing a hose fitting 1 according to an embodiment of the present invention will be described by taking as an example a process of producing the hose fitting 1 having the above-described configuration. First, the material of the processing material used to manufacture the fitting is a carbon steel wire for cold heading or its equivalent to prevent embrittlement because it is formed by plastic working, especially cold forging. Is selected. For example, SWCH6A of JIS standard (JIS G 3539) is adopted, which is obtained by subjecting a material to spheroidizing annealing, surface treatment (surface lubrication treatment), wire drawing, and coiling. The drawing in the defined tensile test method of metal material (hereinafter simply referred to as a tensile test) is 75% or more. As the plastic processing equipment , a multistage part former is used.
[0017]
First, the first step of the present invention is performed. A first intermediate molded article 14 is formed by plastic working the starting member 13 shown in FIG. 1A obtained by cutting the coiled SWCH 6A. In the first molding step, the socket portion 2 is formed, and the protruding portion 15 is formed at the inner axial position. The protruding portion 15 is a portion to be a nipple portion 3 in a later process, and is formed of a solid cylindrical body having a volume and an outer diameter corresponding to the nipple portion 3.
[0018]
Thereafter, the second intermediate molded product 16 is formed by plastic working the first intermediate molded product 14 in the second molding step shown in FIG. 1 (c). The first molding step is mainly performed on one end side, whereas the other end side is mainly formed here. In the second molding step, the other end side of the first intermediate molded product 14 is reduced in diameter to form the flange portion 12 projecting radially outward, and the other end side is recessed in the axial direction to form the recess 8. And the shaft wall part 6 is formed.
[0019]
Next, in the third molding step shown in FIG. 1 (d), the second intermediate molded product 16 is further plastically processed to form a third intermediate molded product 17. And here is to perform the molding of the nipple portion 3, the sealing portion 10 and the shaft hole 7. As a processing method at this time, for example, the third intermediate molded product 17 is fixed to a die, and a guide holder provided with a punch is inserted into the socket portion 2 to press-fit the punch into the protruding portion 15. Then, a thin pipe, that is, the nipple portion 3 is formed by backward extrusion. This punch press-fitting may be performed over several stages such as two stages. Then, following the formation of the nipple portion 3, the shaft hole 7 is penetrated to the concave portion 8 by punching. It is preferable to mold the seal portion 10 in parallel with the nipple molding. For example, if a die having a predetermined shape is formed on a die, the seal portion 10 can be molded simultaneously with punching.
[0020]
Here, the first step by plastic working is completed, but during this time, plastic working is performed without any annealing step. This is because SWCH6A with a drawing of 75% or more in the tensile test is used as a raw material, so even if work hardening occurs to some extent, ductility does not decrease so much and plastic working can be easily performed. Thereby, processing efficiency can be raised and manufacturing cost can be reduced.
[0021]
When the hardness of the intermediate product obtained in the first step was examined, it was slightly different in that part, but it was in the range of Hv 200 ± 20 in terms of Vickers hardness.
[0022]
Subsequently, the second step is performed as shown in FIG. This step is substantially a finishing step. Here, the groove 11 is formed by machining using, for example, an NC machine tool or an automatic board. You may finish the sealing part 10 shape | molded by the 3rd shaping | molding process. Thus, the head 4 is finished. Further, the threaded portion 5 is processed by a lathe or the like, whereby the hose fitting 1 having a predetermined shape can be obtained. In addition, you may make it shape | mold the screw part 5 with a rolling tap.
[0023]
Thus, in the manufacturing method of the present invention, at least the socket portion 2 , the nipple portion 3 and the shaft hole 7 are formed by plastic working and the head 4 is finished by machining, so that it has excellent dimensional stability and shortens the manufacturing process. And suitable for mass production, and the generation of chips can be minimized. The manufactured hose fitting 1 has an integral structure, and in particular, since the socket portion 2 and the nipple portion 3 are integrally formed, there is no possibility of oil leakage even if it is adopted for a high hydraulic hose.
[0024]
Further, as described above, if the molding of each part other than the socket part 2 , the nipple part 3 and the shaft hole 7 is included in the first process by plastic working, the second process by subsequent machining can be simplified. It is possible to improve process length, mass productivity, and cost.
[0025]
In this embodiment, since a material with a drawing of 75% or more was used in the tensile test, it has sufficient ductility even after plastic working, and is immediately caulked to the hose 22 and the fitting 1 without performing annealing. Even if it gives, a crack will not arise in the socket part 2. FIG. In addition, a small number of cracks occurred when the hose fittings were manufactured from the materials of JIS standard SWCH12A to HWCH15A in the same process as described above and the hose 22 and the fitting 1 were caulked immediately. It was. It is considered that this is because the drawing in the tensile test of these materials is 55 to 70%.
[0026]
In this example, SWCH6A was used as the material, but a material called a commonly known extremely low C material having a carbon content of 0.02% or less (for example, ELCH-2 manufactured by Kobe Steel) can be used. . Incidentally, the drawing in the tensile test of this material was 90%, and the hardness was Hv190 ± 20 when the same plastic working as in the first step was performed.
[0027]
The SWCH12A has a carbon content of about 0.12%, but the annealing condition of the material is selected and the drawing in the tensile test is set to 75% or more, and the degree of plastic processing is set appropriately so that the hardness after one step is If it becomes Hv170-270, the effect similar to the said Example can be exhibited.
[0028]
In the above-described embodiment, the female portion having a female screw (female fitting) is shown. However, the present invention is not limited to this, and the same socket portion, nipple portion, such as a male fitting and glasses fitting. And it is widely applied to a fitting with a head.
[0029]
A brake hose applied to automobiles and the like can be manufactured using the hose fittings manufactured by the above-described manufacturing method.
[0030]
FIG. 6 shows the whole of such a brake hose. The brake hose 21 is configured by attaching the hose fitting 1 to both ends of the hose 22. Specifically, the end portion of the hose 22 is inserted into the socket portion 2 of the hose fitting 1, and the socket portion 2 is crushed inward in the radial direction from the outer peripheral side to be crimped, whereby the hose 22 is nipple portion 3 The hose 22 and the fitting are integrally fixed. According to the brake hose 21, an inexpensive brake hose 21 with excellent sealing performance and reliability can be manufactured. In addition, although the example using the two metal fittings 1 for hose was shown here, this may be only one, for example, it is also possible to use 3 or more in a trifurcated hose etc.
[0031]
【The invention's effect】
In short, according to the present invention, fluid leakage prevention, cost reduction, dimensional stability, chip treatment reduction, process shortening, mass productivity improvement, strength maintenance of the nipple part can be achieved, and annealing and annealing after plastic working Even if the caulking process is performed immediately without performing a heat treatment such as the above, the socket portion is not cracked, so that the heat treatment step can be reduced and the product cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a side cross-sectional view showing a hose fitting and a manufacturing method thereof according to an embodiment of the present invention.
FIG. 2 is a side sectional view showing a brake hose according to an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Hose fitting 2 Socket part 3 Nipple part 4 Head part 5 Screw part 8 Recessed part 10 Seal part 11 Groove part 12 Collar part 21 Brake hose 22 Hose

Claims (3)

A hose fitting having a socket part on one end side, a nipple part located inside the socket part and a shaft hole, and a head part on the other end side, which are integrally formed of the same material. A steel material having a drawing of 75% or more in a metal material tensile test method (JIS Z 2241) is used as a material for the hose fitting, and the socket portion, the nipple portion, and the shaft hole are formed. A method of manufacturing a hose fitting, comprising a first step of forming by plastic working and a second step of finishing the head by machining. A hose fitting that has a socket part on one end side, a nipple part located inside the socket part and a shaft hole, and a head part on the other end side, which are integrally formed of the same material. As a material for the hose fitting, a steel material with a drawing of 75% or more in the tensile test method (JIS Z 2241) of a metal material is used, and the socket part, the nipple part, and the shaft hole are formed by plastic working. A hose fitting that is molded and machined to finish the head . A brake hose comprising a hose fitting manufactured by the manufacturing method according to claim 1 attached to an end of the hose .

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