JP3121549B2 - Manufacturing method of hose fittings - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an outer periphery of a nipple.
And a method for manufacturing a hose fitting having a socket portion .

[0002]

2. Description of the Related Art At a mounting end of an industrial hose, a hose fitting is used in consideration of detachability, leakage prevention and reliability. This hose fitting is provided with a socket portion on one shaft end side on the hose side and a nipple portion on the inside thereof in a double tubular shape, and a head portion having a screw portion or the like on the other shaft end side. It is configured.

As a method of manufacturing this type of hose fitting, there are a method of forming each part by cutting, a method of separately manufacturing a body part including a socket part and a head part and a nipple part, and integrating these parts by brazing. Or a method in which the main body and the nipple are integrated by caulking.

[0004]

However, of the above-mentioned conventional manufacturing methods, the method based on the whole cutting method is not suitable for mass-produced products because a large amount of chips is generated, the working speed is slow, and the cost is high. Absent. Further, there is a disadvantage that the dimensional stability is lacking.

In the brazing method, the main body is usually manufactured by plastic working such as a parts former, the nipple is manufactured by cutting a round bar or a pipe material, and the nipple is pressed into the main body, and then the copper brazing is performed. Brazing with such as. The brazing method is excellent in mass productivity, but the nipple cutting step remains. Press fitting for brazing, copper ring insert,
Processes such as alignment on a tray, brazing, and copper brazing check after brazing are required, which causes high costs. Further, the nipple portion is softened by brazing, which may cause the nipple to collapse during hose crimping. If the brazing is not performed properly, there is a problem that fluid (oil) may leak from the press-fit connection portion.

Further, it is considered that the caulking method has a shorter process than the brazing method, has less nipple collapse, and has no cost problem. However, since the risk of fluid leakage from the swaged portion is much larger than that caused by brazing, this is a technique that is hardly adopted in practice.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and can prevent the nipple from being crushed at the time of hose crimping, and can improve the reliability by eliminating the connection between the nipple and the main body. Still another object of the present invention is to provide a method of manufacturing a hose fitting which can be manufactured at a low cost by simplifying the manufacturing process.

[0008]

In order to solve the above-mentioned problems,
The method for manufacturing a hose fitting according to the present invention includes a columnar projection, a tubular socket provided on an outer periphery of the projection,
An intermediate molded product in which the head connecting the projection and the socket at one end is integrally molded of the same material
After performing cold plastic working on the protrusions of the intermediate molded product to form a tubular nipple portion, a shaft hole of the nipple portion is punched into the head side. And is characterized by being penetrated by

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 2, a manufacturing method according to the present invention uses a projection 2 of an intermediate molded product 21 in which a projection 24, a socket 3 and a head 22 are integrally formed of the same material.
4 to form a nipple 2 by plastic working
Since it is mainly formed by cold plastic working, it has excellent dimensional stability and can simplify the manufacturing process, so that it is suitable for mass productivity.

[0010]

FIG. 1 is an explanatory view of a specific embodiment of a hose fitting according to the present invention. The hose fitting 1 includes a nipple portion 2, a socket portion 3 provided on the outer periphery of the nipple portion 2, and a head portion 4 connecting the nipple portion 2 and the socket portion 3 at one end. 2, the socket part 3 and the head part 4 are integrally formed of the same material. A step-shaped collar 6 is formed at a boundary position between the socket 3 and the head 4.

The socket portion 3 is formed in a tubular shape having an outer diameter and a length so as to be appropriately fitted on the outer periphery of the hose end. The nipple portion 2 has substantially the same length L1 as the socket portion 3.
And is formed as a small-diameter pipe having a predetermined outer diameter Φ1 and an inner diameter Φ2. The specific dimensions are, for example, L
1 = 18 mm, Φ1 = 3.5 mm, Φ2 = 2.3 mm.

The nipple portion 2 is formed integrally with a shaft wall 7 formed radially inward of the flange portion 6. A space 9 opened at one end is formed radially inward of the head 4, and a screw groove is threaded along an outer edge of the space 9 to form a female screw portion 5. Shaft hole 8 of nipple 2
Penetrates into the space 9 formed in the head 4 through the shaft wall 7. A frustoconical seal portion 10 is formed on the space 9 side of the shaft wall 7, and a shaft hole 8 penetrates the shaft center.
In addition, a groove 11 is formed on the outer peripheral surface of the head 4.

In the base 1 of the present invention, the nipple 2 and the socket 3 are integrally formed of the same material.
As described later, the nipple portion 2 is characterized by having a higher hardness than the socket portion 3.

Next, an embodiment of the method of manufacturing the hose fitting of the present invention will be described. First, as a first molding step, as shown in FIG.
(Head) The intermediate molded product 21 integrated with 22 is cold-formed
Forming by cold working, for example . As a material for forming the intermediate molded product 21 by cold forging , a carbon steel wire for cold heading (SWCH12 or SWCH15) or an equivalent product thereof is selected, and a material subjected to normal annealing treatment and lubrication treatment is used. As the plastic working equipment, a multi-stage parts former or the like is used.

The intermediate molded product 21 has a cylindrical projection 24
A socket portion 3 provided on the outer periphery of the projection portion 24, and a base portion 22 connecting the projection portion 24 and the socket portion 3 at one end. The projection portion 24, the socket portion 3, and the base portion 2
2 is integrally formed of the same material, and a base portion 22 is provided with a pilot hole 23 in which the screw portion 5 is formed. The protruding portion 24 has a columnar shape, has the same volume and outer diameter as the nipple portion 2, and has one end continuously and integrally formed with a partition wall portion 25 corresponding to the shaft wall 7. The specific dimensions of the protruding portion 24 are, for example, an outer diameter Φ3 = 3.5 mm and a protruding length L2 = 10
mm.

The intermediate molded product 21 can be manufactured by machining alone or by a combination of plastic working and machining.

The intermediate molded article 21 having a predetermined shape after the first molding step is then annealed . This is to facilitate plastic working in the second forming step, which is a later step,
This is for hardening the nipple portion and adjusting the annealing conditions to make the protruding portion as soft as possible. As the annealing conditions, for example, 880 ℃ ~ in an oven
After heating at 900 ° C. for about 2 hours, it is gradually cooled over 7 hours or more so as to have a hardness of, for example, Rockwell B scale 60 or less. Moreover, you may make it perform a lubrication process together with an annealing process.

After the annealing step, the nipple 2 is formed by further plastically processing the projection 24 as a second forming step. At the time of molding, as shown in FIG.
A nipple forming device 41 composed of a cylindrical guide 42a inserted into the inside of the guide holder 42, a guide holder 42, and a punch 43 which is a carbide cylinder provided in the guide holder 42 is used. The outer diameter of the punch 43 is the diameter Φ of the shaft hole 7.
It is formed to be equal to 2. Guide holder 4
2 is a hold hole 44 for holding the punch 43;
A guide hole 45 having an inner diameter equal to the outer diameter of the protruding portion 24 is provided.

At the time of plastic working, the nipple forming device 4
1 is set coaxially with a die (not shown), and the guide holder 42 and the punch 43 are advanced by a hydraulic press. And the deformation force of the projection portion 24 is, for example, 20 Ton.
/ Cm ² , punch 43 with a pressing force of about 1 Ton
Into the protruding portion 24. By this press-fitting, the shaft hole 8 having the same diameter as the punch 43 is formed in the protruding portion 24, and the displaced portion is formed between the outer peripheral wall of the punch 43 and the inner wall of the guide hole 45 of the guide holder 42. Push backwards. That is, the nipple portion 3 can be formed by plastic working by backward extrusion using the guide holder 42 as a container. This press-fitting may be performed over several orders such as two steps. Also, if the punch 43 is not pushed straight along the axis, there is a risk of breakage.
It is preferable that the distal end surface 24a of the protruding portion 24 be a flat surface perpendicular to the axis.

After the nipple portion 2 is formed, the shaft hole 8 is penetrated to the bottom surface of the pilot hole 23 by punching. This punching may be performed by another press device, but it is preferable that the punch 43 is configured to be able to advance and retreat with respect to the guide holder 42, and that the punching is performed following the backward extrusion. Further, it is preferable to form the seal portion 10 in parallel with this forming. For example, if a die having a predetermined shape is formed in a die, the seal portion 10 can be formed simultaneously with punching. Also, the base 2
The brim portion 6 is formed by performing die forging or punching on 2. In this way, a metal fitting having a shape as shown in FIG. 3 (an intermediate product before machining) is obtained.

Next, as a machining process, for example, NC machining
The screw portion 5 and the groove portion 11 are formed using a machine or an automatic lathe. As shown in FIG. 5, the screw portion 5 has a predetermined screw length L4 with respect to the prepared hole 23 by using a rolling tap (not shown).
(For example, about 10 mm) and an inner diameter Φ4 (for example, about 9 mm). Further, the seal portion 10 formed by plastic working is formed to have a predetermined conical angle θ (for example, 84 degrees), and the end surface 23a of the bottom surface has a diameter Φ5 (for example, 7.5 mm) appropriately larger than the shaft hole 7. Finish processing so that it becomes. In addition, you may shape | mold the seal part 10 not by plastic working but by this machining process. Thus, as shown in FIG. 1, a hose fitting 1 having a predetermined shape is obtained.

As described above, according to the manufacturing method of the present invention, the head 4
And cold forging technology of the socket part 3 and the nipple part 2
Since the cold forging technology is optimally combined and a forming method mainly based on plastic working is employed, the method is excellent in dimensional stability, the manufacturing process can be shortened, and a method suitable for mass productivity can be obtained. Further, since the cutting process is limited to a part such as the formation of the screw portion 5, the generation of chips can be suppressed to a minimum.

[0023] The important thing is, the nipple portion 2, baked
By being blunted and undergoing backward extrusion plastic working, it becomes hard, for example, 90 to 95 on a Rockwell B scale, so that there is no risk of crushing when crimping the hose. In addition, the socket portion 3 is also softened by performing an annealing step before processing the nipple portion 2 (5 in Rockwell B scale).
5-60), and can be easily attached to the hose. The manufactured hose fitting 1 has an integral structure, and there is no risk of oil leakage even when employed in a high-hydraulic hose.

In the above embodiment, the ratio between the punch diameter (Φ2) and the growth diameter (L1) for the backward extrusion of the nipple is about 8, and the ratio (5 to 6) applied to the ordinary backward extrusion. ). Therefore, in order to realize this, it is natural to sufficiently provide a high-precision hydraulic press, a high-precision mold, and a carbide material of the punch.
There is .

The hose fitting according to the present invention has the following advantages:
In all aspects, such as dimensional stability, chip disposability, mass productivity, number of steps, nipple strength, and sealability, it has superior effects to conventional hose fittings.

In the above embodiment, a female screw having a female thread (female metal fitting) is shown. However, the present invention is not limited to this, and is widely applied to a metal fitting having a similar nipple, such as an eyeglass metal fitting. Applicable.

FIG. 6 shows an example in which the fitting of the present invention is caulked and fixed to the end of the hose to form a brake hose. Both ends of the hose 50 are inserted between the nipple portion 2 and the socket portion 3 of the fitting 1, and a plurality of portions of the socket portion 2 are compression-molded to form a caulking portion 51.

[0028]

As described above, according to the present invention, as a method for manufacturing a fitting for a high-pressure hose, a material is nicked.
Since the molding method is mainly plastic working until the formation of the pull, the method is excellent in dimensional stability, can shorten the manufacturing process, and can be a method suitable for mass productivity. In addition, since the cutting step is limited to a part such as the formation of a screw portion, an excellent effect that generation of chips can be minimized is exhibited.

[Brief description of the drawings]

FIG. 1 is an explanatory side sectional view of a specific embodiment of a hose fitting according to the present invention.

FIG. 2 is an explanatory side sectional view of one embodiment of an intermediate molded product used in the present invention.

FIG. 3 is an explanatory side sectional view of an intermediate product according to an embodiment of the present invention.

FIG. 4 is an explanatory side sectional view of one embodiment of a plastic working method by backward extrusion.

FIG. 5 is an explanatory side sectional view of an embodiment of a method for processing a head.

FIG. 6 is an explanatory side sectional view of a brake hose using a fitting manufactured according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Hose fitting 2 Nipple part 3 Socket part 4 Head 5 Screw part 6 Flange part 7 Shaft wall 8 Shaft hole 9 Space 10 Seal part 21 Intermediate molded product 22 Base part 24 Projection part 50 Hose

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshihiro Namekawa 3-1-1, Sukekawa-cho, Hitachi-shi, Ibaraki Pref. Inside the wire plant of Hitachi Cable Co., Ltd. Hitachi, Ltd. Automobile Equipment Division (72) Inventor, Shuya Murakami 4-6, Kanda Surugadai, Chiyoda-ku, Tokyo Hitachi, Ltd. (56) References JP-A-60-26876 (JP, A) JP-A Sho 55-97838 (JP, A) JP-A-63-125889 (JP, A) JP-A-2-80148 (JP, A) Patent 3072975 (JP, B2) Patent 3029776 (JP, B2) (58) (Int.Cl. ⁷ , DB name) F16L 33/00-33/34

Claims (9)

(57) [Claims] 1. A projection comprising: a cylindrical projection; a tubular socket provided on the outer periphery of the projection; and a head connecting the projection and the socket at one end. Intermediate molded product in which the head and head are integrally molded of the same material
After cold plastic working is applied to the material and molded, and the projection of the intermediate molded product is subjected to cold plastic working to form a tubular nipple portion, an axial hole of the nipple portion is formed on the head side. A method for manufacturing a hose fitting, characterized in that the hose is punched and penetrated. 2. The intermediate molded product is opposite to the socket portion of the head.
The method for producing a hose fitting according to claim 1, wherein a pilot hole is provided in the hose. 3. An intermediate molded product is annealed, and then plastically
The method for producing a hose fitting according to claim 1 or 2, wherein the nipple portion is formed by performing a working process. 4. The socket portion after the intermediate molded product is annealed.
4. The method for manufacturing a hose fitting according to claim 3, wherein the nipple portion is formed by subjecting the projection to plastic working without subjecting the projection to plastic working. 5. The method for manufacturing a hose fitting according to claim 1, wherein the nipple portion is formed by subjecting the protrusion to plastic working by backward extrusion . 6. A shaft hole is punched following formation of a nipple portion.
A method for producing a hose fitting according to any one of claims 1 to 5, wherein 7. A seal portion is formed on the head at the same time as punching the shaft hole.
A method for manufacturing a hose fitting according to any one of claims 1 to 6. 8. A collar portion is formed on the head during plastic working of an intermediate molded product.
The manufacturing method of the hose fitting according to any one of claims 1 to 7, which is formed . 9. A method for forming a through hole on a head by machining.
The method for producing a hose fitting according to any one of claims 1 to 8, wherein the joint is formed .