JP3862611B2 - Manufacturing method of pipe for pretensioner - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a pretensioner pipe, and more particularly to a method for easily and inexpensively manufacturing a highly reliable pretensioner pipe that can sufficiently withstand an explosion of explosives.
[0002]
[Prior art]
In recent years, an increasing number of seat belt devices equipped with a pretensioner are installed in a vehicle such as an automobile.
The pretensioner ignites gunpowder in response to a detection signal transmitted at the time of a vehicle collision, accelerates the driving body by the gas pressure generated by the explosion of the gunpowder, and winds a seat belt by the accelerated driving body. The take-up shaft to be rotated is instantaneously rotated in the take-up direction to take up the seat belt and apply tension to the seat belt.
[0003]
A conventional example of such a pretensioner is shown in FIG.
The pretensioner 50 includes a pretensioner pipe 51. The pretensioner pipe 51 integrally includes a storage portion 51a for the gas generator G and a passage portion 51b for storing and guiding a plurality of balls B.
The gas generator G housed in the housing part 51a explodes in response to a signal at the time of a vehicle collision, and releases high-pressure gas into the passage part 51b. The ball B accommodated in the passage 51b is accelerated by the energy of the high-pressure gas, and the ring gear 52 that rotates the winding shaft that winds the seat belt in the winding direction is rotated.
[0004]
Here, the pipe 51 for the pretensioner is generally formed such that the accommodating portion 51a of the gas generator G is larger in diameter and thicker than the passage portion 51b for accommodating and guiding the driving body B such as a ball. In addition, a space for storing the gas generator G is secured, and a structure that can withstand the explosion of the explosive in the gas generator G is adopted.
[0005]
The pretensioner pipe 51 having the above-described structure conventionally uses an electric sewing tube or the like in which a seam is present, and performs a plurality of tube expansion processes on the electric sewing tube to accommodate and guide the driving body B. After the pipe body having the diameter of 51b is cut, the pipe body is cut into a length considering the product dimensions, and the end portion of the cut product is subjected to pipe expansion processing and thickening processing to accommodate the storage section 51a of the gas generator G. It was made to manufacture by forming.
[0006]
[Problems to be solved by the invention]
However, in the pretensioner pipe 51 using the above-described electric resistance welded pipe, the joint portion is inevitably weak against an impact caused by an explosion of explosives, and the reliability as a high-pressure piping component is poor.
Further, in the above-described conventional manufacturing method, after the entire tube is once expanded into a thin-diameter, thin-walled tube body that becomes the passage portion 51b for housing and guiding the driving body B, the housing portion 51a of the gas generator G is formed. Therefore, the tube end portion that is the storage portion 51a of the gas generator G is repeatedly subjected to contraction and expansion, so that fine cracks and Cracks were likely to occur and the yield was deteriorated, and wasteful processing was performed, which increased the processing cost.
[0007]
The present invention has been made in view of the problems of the above-described conventional method for producing a pretensioner pipe, and the object thereof is to provide a highly reliable pretensioner pipe that can sufficiently withstand an explosion of explosives. An object of the present invention is to provide an easy and inexpensive method for manufacturing.
[0008]
[Means for Solving the Problems]
In order to achieve the above-described object, the present invention integrates a housing portion of a gas generator with a passage portion that houses and guides a driving body that is accelerated by the gas generated from the gas generator and rotates a seat belt winding shaft. A pretensioner pipe manufacturing method according to the present invention, wherein the pretensioner pipe is manufactured by subjecting a seamless base tube to a plurality of tube drawing processes, and at least prior to the final tube drawing process. Tsu by the applying the processed pipe previously formed by Shinkan processing of the final to the product length length, and the final Shinkan processed only in a portion excluding the one end portion of the work pipe by swaging machine Then, leave a cylindrical part with a large diameter and a thick wall that can be used as a storage part for the gas generator at one end, and remove the other part by final drawing with a swaging machine. Was manufacturing method of the pipe pretensioners Shinkan from the tube of the wide径且one thick, which may be a housing portion to the small-diameter and thin tube may be a channel portion for accommodating guide the driver of the generator.
[0009]
According to the above-described method for manufacturing a pretensioner pipe according to the present invention, since the pretensioner pipe is manufactured by subjecting the seamless element tube to a plurality of times of drawing, a highly reliable pretensioner pipe is provided. Can provide.
In the present invention, at least prior to the final drawing process, the pipe to be processed is formed to have a product length by the final drawing process, and the final drawing process is performed by a swaging machine. By applying it only to the part other than the one end of the processed tube, leave a cylindrical part with a large diameter and a thick wall that can be used as a storage part for the gas generator at one end, and the other part by the final tube processing by a swaging machine. In order to form a gas generator housing portion, the tube is extended from a wide and thick tube body that can be used as a gas generator housing portion to a thin and thin tube body that can be used as a passage portion for housing and guiding the drive body. Because one end removed from the final tube-drawing process can be used as the gas generator housing without further pipe expansion and wall-thickening processes, the number of processing steps can be reduced. Easily and inexpensively be manufactured pipes pretensioner.
[0010]
Note that the “final tube drawing” in the present invention does not refer to the final one tube drawing, but the final tube drawing, that is, the diameter of the tube serving as the housing portion of the gas generator and This means that the tube expanded to the wall thickness is the tube diameter and thickness of the tube that will be the passage part that accommodates and guides the drive body, and the tube expansion at the final stage is swaging. A case where the machine is divided into a plurality of tube drawing processes is also included in the scope of the technical idea of the present invention.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, although one embodiment of the manufacturing method of the pipe for pretensioner concerning the above-mentioned present invention is described in detail, the present invention is not limited to the following embodiment at all.
[0012]
First, a conventional draw bench was used for a carbon steel seamless pipe (JIS G 3455) having an outer diameter of 34 mm and a wall thickness of 4.5 mm formed by, for example, Mannesmann mill drilling, mandrel mill rolling, or the like. A tube having an outer diameter of 16.3 mm and a wall thickness of 2.6 mm is formed by drawing a tube or using a swaging machine (FIG. 1A).
[0013]
Subsequently, the tubular body having an outer diameter of 16.3 mm and a wall thickness of 2.6 mm is cut into a length of 132.6 mm by a cutting machine (FIG. 1B).
This cutting length is cut to a length that becomes the product length by the tube drawing process in the final stage later.
[0014]
Subsequently, one end of the cut product is left at 40 mm, and the other part is drawn at the final stage so that the outer dimensions are 14 mm, the wall thickness is 1.5 mm, and the total length is 251.92 mm [FIG. c)].
This final stage of tube drawing can be easily performed by tube drawing using a swaging machine that extends the tube body in the axial direction while striking the tube body from the outer peripheral direction.
[0015]
For example, as shown in FIG. 2, the processing tube A is set in the swaging machine S in a state where one end is not processed, and the processing tube A is moved while the die D is hit from the outer periphery of the processing tube A at a high speed. By doing so, only the portion excluding the one end portion of the tube A can be subjected to the tube extending process. Note that M in FIG. 2 is a mandrel inserted into the processed tube A.
[0016]
Thereafter, terminal molding, bending, etc. are performed as necessary.
[0017]
The tubular body manufactured in this way has a wide-diameter and thick cylindrical portion that can serve as a storage portion of the gas generator at one end thereof, and extends in a state of communicating from the wide-diameter and thick cylindrical portion. This is a tube body integrally having a thin and thin long cylindrical portion that can be used as a passage portion for accommodating and guiding the tube, and can be suitably used as a pretensioner pipe.
[0018]
As mentioned above, although one embodiment of the present invention has been described, the present invention is not limited to the above-described embodiment.
For example, in the above-described embodiment, the seamless element pipe used is formed by Mannesmann mill drilling, mandrel mill rolling, etc., but any manufacturing method can be used as long as it is a seamless seamless pipe body. You may use what was done.
In the above embodiment, the pipe to be processed is cut to a length that takes into consideration the product dimensions immediately before the final stage of the pipe drawing. The seamless base tube may be cut to a length that takes into account the product dimensions from the stage of manufacturing the seamless base tube.
Furthermore, as described above, the final tube drawing process can be carried out in a plurality of tube drawing processes.
[0019]
【The invention's effect】
As described above, according to the method for manufacturing a pretensioner pipe according to the present invention described above, since the pretensioner pipe is manufactured by subjecting the seamless element tube to a plurality of tube-drawing processes, a highly reliable pretensioner is provided. There is an effect that can provide the pipe.
Further, according to the pretensioner pipe manufacturing method of the present invention, at least prior to the final tube drawing process, the pipe to be processed is formed to a length that is the product length by the final tube drawing process, The swaging machine is applied to only the portion excluding one end of the tube to be processed , leaving a large diameter and thick cylindrical portion that can be used as a gas generator storage portion at one end, and the other portion. Because the tube is drawn from the wide and thick tube that can be used as the gas generator housing to the thin and thin tube that can be used as the passage that houses and guides the driving body, the tube is finally drawn by the swaging machine. The end portion removed from the final tube drawing process can be used as the gas generator storage portion without further pipe expansion and thickening to form the gas generator storage portion. Come, since the can be reduced in number of processing steps, there is a readily and inexpensively be produced pipes for pretensioner effect.
[Brief description of the drawings]
FIG. 1 is a diagram conceptually showing a method of manufacturing a pretensioner pipe according to the present invention.
FIG. 2 is a diagram conceptually showing an example of a final tube drawing process.
FIG. 3 is a diagram illustrating the structure of a pretensioner with a pretensioner pipe as the center.

Claims (1)

A method of manufacturing a pipe for a pretensioner, which integrally includes a housing portion of a gas generator and a passage portion that houses and guides a driving body that is accelerated by the gas generated from the gas generator and rotates a winding shaft of a seat belt. Thus, the pretensioner pipe is manufactured by subjecting the seamless pipe to a plurality of tube drawing processes, and at least prior to the final tube drawing process, the pipe to be processed is subjected to the final tube drawing to obtain the product length. A wide diameter that can be used as a gas generator storage section at one end by applying a final tube-drawing process to only a portion other than one end of the tube to be processed by a swaging machine. Wide diameter that can leave the thick cylindrical part and the other part can be used as the storage part of the gas generator by the final tube drawing by swaging machine And small diameter may be a passage for accommodating guides the driver from the tubular body of the meat, characterized in that Shinkan until thin tube, pipe manufacturing method of the pretensioner.

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