JPH0890259A - Reforming method of press-contact burr and reformed gas generator - Google Patents

Abstract

PURPOSE: To provide a simple an inexpensive reforming method of press-contact burrs to generate no cutting layer by pressing a roller having the prescribed tooth profile against an article body to be joined during or after the frictional pressing of press-contact burrs. CONSTITUTION: Press-contact burrs 28 are pressed against a joining part 26 by a roller 51 to achieve the reforming without generating the cutting chips, etc., and the reformed surface does not generate any catch during the handling, or no deburred pieces fall. In particular, when reforming is achieved by the so-called knurling where the prescribed tooth profile is provided on the roller 51, the appearance of a product is improved, and the utilization for the discrimination of the product or the process control can be realized by stamping the pattern or the symbol on the product. Such a reforming method is effective in preventing the generation of cutting chips or deburred pieces, and especially effective in the case where the work to be joined generally contains an electrical contact in its structure or in the case of a gas generator 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for shaping a pressure welding burr formed at a friction welding portion.

[0002]

Friction welding is a rod of light metal such as aluminum,
It is used for joining pipes, thermoplastic plastics, etc., and is specifically used for crankshafts of automobiles, drums of copying machines, gas generators for airbags, and the like.
For friction welding, fix one of the pieces to be joined,
The other is rotated and brought into pressure contact, and welding is performed using friction heat. Although this technique is useful, its joint is covered by the amorphous crystal structure of the base material. Generally, this structure is called pressure welding burr, but it not only looks bad,
Since the structure is sharp and brittle, it causes a big trouble in handling. Therefore, conventionally, a shaping method of scraping off the pressure contact burr has been generally used. However, in this shaping method of scraping off, a large amount of cutting waste is generated, and there is a risk of insulation failure due to the adhesion of this cutting waste, so that the object to be joined is, for example, a gas generator for an airbag which is a safety device of an automobile. This method is not suitable for the precision equipment of (in fact, there are known cases where non-deployment or malfunction of the airbag was caused by poor insulation due to cutting chips or burr falling pieces). Therefore, in the case of these gas generators and the like, in most cases, the pressure welding conditions have been studied to reduce the size of the burr crystal grains, and the pressure welding burr is not shaped and used as is.

A concrete example of applying friction welding to the latter gas generator for an air bag will be described with reference to FIGS. 6 to 8. In FIG. 6, the gas generator 1 has a cylindrical container-like appearance,
For example, it comprises an upper container 2 and a lower container 3 made of an aluminum alloy. The upper container 2 is a hollow cylinder having an outer wall 16 and an inner wall 15, and the lower container 3 is a lid, both of which are integrated by friction welding, and burrs are swelled at the joints 26 and 27 of the outer wall 16 and the inner wall 15. Is grooved in advance, and the pressure contact burrs 28 and 29 swell to fill the recesses. As described above, when the groove is processed in advance, deburring after pressure welding can be unnecessary or reduced, but the main body becomes thin due to the formation of the concave portion, and the strength cannot be reduced. The integrated gas generator 1 is divided into a central portion 5 and a ring-shaped outer peripheral portion 4 by an inner wall 15.
Further, the lower container 3 has a cylindrical portion 3a protruding upward in the central portion 5.
Is formed, and the squib 17 that operates by receiving current supply through a collision sensor (not shown) is formed in the cylindrical portion 3a.
Is stored in the squib 17, and the transfer charge 18 is put in contact with the squib 17.
Are arranged above the central portion 5. This squib 17
Constitutes the ignition means, and the central portion 5 constitutes the ignition chamber. The outer peripheral portion 4 has a ring-shaped partition wall 12 and a filter cover 25.
Are divided into four chambers, and the gas generating agent 9 is housed in the inner diameter side upper stage, the first cooling filter 20 is housed in the inner diameter side lower stage, the second cooling filter 10 is housed in the outer diameter side lower stage, and the filtration filter 11 is housed in the outer diameter side upper stage. ing. First and second cooling filters 20,
A wire mesh or the like is used for 10, and a ceramic filter or the like is used for the filtration filter 11. The ignition chamber 5 is provided on the inner wall 15.
From which the first gas hole 15a leading to the gas generation chamber 6 is opened,
In addition, the partition wall 12 has a second gas hole 12 a that connects the gas generation chamber 6 and the cooling filter chamber 7, and a first cooling filter chamber 19
And the third gas hole 12b for communicating the second cooling filter chamber 7 with each other.
Is provided, and a gas passage 25a that connects the second cooling filter chamber 7 and the filtration filter chamber 8 is provided. Further, a gas hole 16a that communicates the filtration filter chamber 8 and the outside is opened in the outer wall 16. ing. Further, the upper container 2 has a flange 2a, and the flange 2a is provided with a mounting hole 30.

Next, the procedure of friction welding of the gas generator 1 will be briefly described with reference to FIG. In FIG. 7 (a),
Put the partition, gas generating agent, filter 10 and the like in the upper container 2,
Attach the squib 17 to the lower container 3. In FIG. 7 (b), the upper container 2 is fixed, the upper container 3 is aligned with the lower container 2, and they are rotated while being in contact with each other. Then, the joints 26, 2
7 is heated and melted by frictional heat, and when the lower container 3 is axially pressed in this state (arrow), as shown in FIG. 7 (c),
A part of the base material of the joint surface is extruded, the joint is metal-bonded, and the extruded base material forms pressure welding burrs 28, 29. The squib 17 may be inserted and attached after joining.

Next, a specific example of how to use the gas generator 1 will be described with reference to FIG. In FIG. 8, the gas generator 1 is attached to the retainer 33 together with the airbag 35 by the bolts 16 through the attachment holes 30 of the flange.
Below the retainer 33, the power supply 41 of the ignition circuit of the gas generator 1, the connector 40, the lead wire 46 and the like are incorporated in the covers 41 and 47, and the upper side of the retainer 33 is located outside the airbag. The bag cover 34 is attached to form the airbag module 31. The airbag module 31 is attached to the center portion of the steering wheel 37 of the automobile by the attachment hole 6. Note that the illustrated example is of a type that uses an electronic collision sensor that does not have an electrical contact built-in, but in the case of a type that uses a mechanical collision sensor, a collision that is an electrical contact of the ignition circuit is further added to the gas generator 1. Some have built-in sensors.

Next, the operation of the gas generator and the airbag module will be briefly described with reference to FIGS. 6 and 8. In FIG. 6, in the gas generator 1, when the collision sensor detects a collision, the squib 17 is energized to ignite and ignite the transfer charge 18. This ignition causes the transfer charge 18 to burn,
The hot air 22 causes the gas generating agent 9 in the gas generating chamber 6 to chemically react, and a large amount of high-temperature gas is generated in a short time. The gas generated is, as indicated by the arrow, the second gas hole 12
a to the first cooling filter chamber 19, is cooled by the first cooling filter 20 to collect the slag, passes through the third gas holes 12b and further passes through the second cooling filter 10, and is cooled by the slag. After being collected, it enters the filtration filter chamber 8 at the final stage through the gas passage 25a. Then, the particulate filter slag is removed by the filtration filter 11 and becomes a clean gas at an appropriate temperature and is jetted from the gas holes 16a into the airbag shown in FIG. As a result, the air bag 35 is inflated and the bag cover 34 is broken to expand to the outside.

[0007]

The method of cutting and shaping the pressure contact burr cannot be applied to precision equipment because a large amount of cutting chips are generated as described above. As shown in FIG. 8, the airbag gas generator 1 may be incorporated with an electric circuit or may have a built-in electric contact. Therefore, the falling piece of the pressure contact burr 28 in FIG. There is a risk of non-deployment or erroneous deployment of the airbag due to insulation failure due to adhesion of cutting chips when the 28 is cut. In addition, when cutting, the main body is slightly cut, which affects the strength of the joint. On the other hand, with the method of reducing the crystal grain of the joint and using it as it is without burr shaping, in the case of a gas generator, the burr of the joint is caught in the hand or handling jig during handling during the assembly process, resulting in an accident. In addition, there is a problem in that the work efficiency is lowered because it is necessary for the worker to wear gloves. Further, in order to obtain no shaping, there is a case where the pressure welding condition such as groove processing is selected to sacrifice the pressure welding strength. It also generally means that friction welding cannot be used when the appearance of the product is important.

The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to provide a simple and inexpensive method for shaping a pressure welding burr that does not generate cutting chips. To provide.

[0009]

In order to solve the above-mentioned problems, the method of shaping a pressure contact burr in the present invention fixes one of the joining pieces of the articles to be joined and presses the other piece while rotating the other to make frictional heat. In a method of shaping a pressure contact burr formed in a joint portion by friction welding in which welding is performed, the pressure contact burr is pressed against a main body of an object to be welded by a roller.

Further, the roller may have a predetermined tooth profile.

In the method for shaping the pressure contact burr described above, the object to be joined has an electrical contact in its structure, or is a gas generator for an airbag, or the material to be joined is It is especially effective when it is aluminum, aluminum, or an aluminum alloy.

Further, the gas generator for an air bag according to the present invention is a gas generator for an air bag in which one container member and another container member fitted thereto are joined by friction welding, and the gas generator is formed at the joint portion. The pressure contact burr thus formed is pressed against the container body by a roller.

[0013]

[Operation] Since the pressure contact burr is pressed against the joint with the roller,
It can be shaped without generating cutting chips, and the shaped surface does not get caught during handling, and there is no risk of burrs falling. In particular, if the roller is shaped by so-called knurling with a predetermined tooth profile, the appearance of the product will be improved, and by applying a pattern or symbol to the product, it will be possible to use it for product identification or process control. . Since the shaping method of the present invention has an effect of preventing the generation of cutting chips and burrs, it is particularly effective when the article to be joined generally includes an electrical contact in its structure or when it is a gas generator. Is.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. First, a first embodiment will be described with reference to FIGS. FIG. 1 is a schematic diagram showing an outline of an apparatus for carrying out the method for shaping a pressure contact burr according to the present invention, FIG. 2 is a sectional view showing how the pressure contact burr is changed by the shaping method according to the present invention, and FIG. It is an external view of the gas generator after applying the pressure contact burr shaping method.

In FIG. 1, an apparatus 50 for carrying out the shaping method of the present invention includes, for example, a rotation holding means 56 for rotatably holding the gas generator 1 and a joint portion 26 of the gas generator which is rotationally driven. The flat roller 51 is formed into a flat shape, and the pressing means 61 presses the gas generator 1 against the flat roller 51 at a predetermined pressure P while rotatably supporting the rotation holding means 56. That is, the upper container 2 of the gas generator has a holding member 56a such as a chuck of the rotation holding means 56.
Thus, it is held rotatably around the central axis 55. The shaft 55 of the rotation holding means 56 is rotatably supported by the shaft support member 60 of the pressing means 61 via a bearing 60. The shaft support member 60 is connected to the piston 59 of the cylinder 58, and a predetermined pressure P is applied by air in the arrow direction. On the other hand, a flat roller 51 having a shaft 52 and rotatable around the shaft 52 is brought into contact with the joint portion 26 of the gas generator 1. The shaft 52 is rotationally driven by, for example, a motor 57. The roller 51 may be rotationally driven by using a dedicated machine, a lathe, or the like. The rotation holding means 56 may be driven to drive the flat roller 51. Alternatively, the rotation holding means 56 may be fixed so that the flat roller 51 is pressed against the gas generator 1 and rotated around it. Good. Further, instead of pressing the gas generator 1 against the flat roller 51, the flat roller 51 may be pressed against the gas generator 1. The above description is a method of performing burr shaping at the same time as pressure contact. In this case, since the burr is shaped in a soft state, the pressing force P of the roller may be small.

On the other hand, since aluminum can be easily shaped even at room temperature, the pressure welding step and the deburring step can be performed separately. In this case, the pressing force P
Is preferably 150 kg / cm ² or more, but even if it is less than 50 kg / cm ² , the intended purpose can be achieved by repeating the pressing operation several times. Generally, it is desirable that the pressing pressure is adjusted according to the type of metal to be frictionally welded. The shaping process is generally carried out at room temperature, but depending on the material to be worked, it is carried out under heating or cooling.

Next, the procedure of shaping will be described with reference to FIGS. First, the gas generator 1 was manufactured by incorporating a gas generating agent, an igniter and the like by friction pressure welding according to the procedure of FIG. 7 described in the prior art. In FIG. 1, pure aluminum was used as the material for the containers 2 and 3, and the diameter of the lower container 3 was 80 mm. The joint portion 28 was rough, and when strongly rubbed with a hand, burrs fell off and the hand was scratched. Next,
As shown in the figure, the upper end of the manufactured upper container 2 of the gas generator 1 is held by the rotation holding means 56, and the flat roller 51 is rotated while being pressed against the joint portion 28 of the gas generator 1. The pressing pressure P was 160 kg / cm ² . Flat roller 5
By the rotation of 1, the gas generator 1 rotates with the rotation of the flat roller 51 while shaping the joint portion 28.

In FIG. 2, the press-contact burr 28 extending in the circumferential direction on the joint portion 26 is flattened as indicated by the two-dot chain line by flesh escaping in the axial direction by the pressing of the flat roller 51 (arrow).

In FIG. 3, in the gas generator 1 thus shaped, the joint portion 26 is smoothed,
There was no fall of the burr and no catch on the hand. Then, when the gas generator 1 was incorporated into the airbag module shown in FIG. 8 and the airbag was inflated, no erroneous deployment or non-deployment occurred, and the result was good. Further, as a result of performing a hydroburst test on an inert model prepared in the same manner, the breaking pressure was 410 kg / cm ² , and the breaking point was not the joint.

Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 4 is an external view of a gas generator to which the shaping method of this embodiment is applied. 4 is different from FIG. 3 in that knurling is used for shaping the joint portion 26. That is, instead of the flat roller 51 of FIG. 1, a roller (knurl) having the tooth profile of the oblique groove 55 as shown in the figure.
Is used. The gas generator container material was pure aluminum, the knurl diameter was φ50 mm, the roller pressing force after pressure welding was 100 to 200 kg / cm ² , the knurling was 20 peaks / inch, that is, the pitch was 1.270 mm, and the knurl width was 5 mm. The result of incorporating the gas generator 1 thus produced into the airbag module was as good as the first embodiment. In addition, the result of the hydroburst test of the inert model created in the same way was 4
It was as good as 30 kg / cm ² . When this shaping method was applied to the airbag module production line, insulation failure was significantly reduced.

Next, a third embodiment of the present invention will be described with reference to FIG. In FIG. 5, it is an external view of the gas generator to which the shaping method of the present embodiment is applied. 5 is different from FIG. 4 in that a knurl having a tooth shape in which a heart shape is engraved is used for shaping the joint portion 26. The result of incorporating the gas generator 1 thus obtained into an airbag module was as good as in the first embodiment. In addition, the result of the hydroburst test of the inert model produced in the same manner was 420 kg / cm ² , which was good.

[0022]

As described above, according to the method of shaping a pressure contact burr of the present invention, the pressure contact burr formed at the joint by friction welding is pressed against the main body of the object to be welded, so that cutting chips are not generated. In addition, it is possible to easily and inexpensively shape the pressure contact burr, and it is possible to significantly reduce the contamination due to cutting chips and burr pieces in the process. Therefore, it is particularly effective when applied to precision equipment such as a gas generator for an air bag. In addition, if the roller is shaped by so-called knurling that has a predetermined tooth profile, the appearance of the product will be improved, and by applying patterns and symbols to the product, it will be possible to use the product for identification and process control. .

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an outline of an apparatus for carrying out a method for shaping a pressure contact burr of the present invention.

FIG. 2 is a cross-sectional view showing how the press contact burr is changed by the shaping method of the present invention.

FIG. 3 is an external view of the gas generator after applying the pressure contact burr shaping method according to the first embodiment of the present invention.

FIG. 4 is an external view of the gas generator after applying the pressure contact burr shaping method according to the second embodiment of the present invention.

FIG. 5 is an external view of the gas generator after applying the pressure contact burr shaping method according to the third embodiment of the present invention.

FIG. 6 is a cross-sectional view of a gas generator to which friction welding is applied.

FIG. 7 is a diagram showing a procedure of friction welding of a gas generator.

FIG. 8 is a sectional view of the airbag module.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Gas generator 2 Upper container (container member) 3 Lower container (container member) 26 Joining part 28 Pressure welding burr 51 Flat roller (roller)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Michitaka Hagiwara 3903-39, Abundant Town, Himeji City, Hyogo Prefecture Nihon Kayaku Co., Ltd. Himeji Factory

Claims (7)

[Claims] 1. A method for shaping a pressure contact burr formed in a joint portion by frictional pressure welding in which one of the joining pieces of an article to be joined is fixed and the other is pressed into contact while being welded by using frictional heat. A method for shaping a pressure-contact burr, which comprises pressing the pressure-contact burr against a main body of an object to be welded with a roller during or after the friction pressure welding. 2. The method according to claim 1, wherein the roller has a predetermined tooth profile. 3. The method for shaping a pressure contact burr according to claim 1, wherein the object to be bonded has an electrical contact in its structure. 4. The method for shaping a pressure contact burr according to claim 1, wherein the article to be joined is a gas generator for an air bag. 5. The method of shaping a pressure welding burr according to claim 1, wherein the material to be joined is aluminum. 6. The method for shaping a pressure welding burr according to claim 1, wherein the material to be joined is an aluminum alloy. 7. A gas generator for an air bag in which one container member and another container member which is fitted thereto are joined by friction welding, wherein the pressure contact burr formed at the joint portion is connected to the container body by a roller. Gas generator for air bag characterized by being pressed.