JP2001246487A - Welding method for combination member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a welding method for a combination member capable of obtaining high dimensional accuracy in axial direction. SOLUTION: In the case of making a combination member 10 by preparing a hollow member 11 and an inserting member 12 and by joining them together by welding with the inserting member inserted into the hollow member; a spot welding part 14 is placed in a superposed part 13 where the hollow member 11 and the inserting member 12 lie one on top of the other, thereby a correcting welding process is provided which corrects a distance between the ends in the axial direction for the hollow member 11 and the inserting member 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention comprises a hollow member and an insertion member inserted and joined to the hollow member such as a valve structure of a fuel injection system, and a high dimensional accuracy is required for an axial end-to-end distance. The present invention relates to a method for welding various kinds of combined members.

[0002]

2. Description of the Related Art An example of a valve structure of a fuel injection system in an internal combustion engine will be described. As shown in FIGS. 13 (a) and 13 (b), this member has a cylindrical housing 91 and a nozzle portion 15.
0, a nozzle 92 having a nozzle portion 150, and a spring 160 for holding the needle 15, a body 92 having an injection hole 929 communicating with the nozzle receiving portion 920. Holding member 16
And

In order to assemble the components to form the valve structure 9, the body 92 is inserted from one end of the housing 91, and the needle 15 held by the holding member 16 is inserted from the other end. Then, the entire circumference is welded to the overlapping portion 93 where the housing 91 and the body 92 overlap. Code 94
Is the entire circumference welded portion.

[0004] When the entire circumference of the overlapping portion 93 is welded, thermal distortion occurs, and the axial dimension of the valve structure may be deviated from a desired value. In the valve structure 9, the clearance C shown in FIG. For this reason, a spacer 97 is arranged on the back of the body 92 as shown in FIG.
The structure is such that appropriate dimensions are secured and the operating range of the needle 15 is appropriate.

In this case, the dimensions of A and B shown in FIG. 1 are measured when the parts are assembled, and the body 92 and the like are ground so that the clearance C has an appropriate dimension. Thereafter, the housing 91 and the body 92 are joined by performing a full circumference welding. The thermal strain caused by the entire circumference welding can be absorbed by the spacer 97. Therefore, it is possible to obtain the valve structure 9 which is hardly affected by the dimensional change of the thermal strain and has accurate dimensional accuracy.

[0006]

In the prior art, however, a spacer 97 must be separately provided for the valve structure 9. In addition to an increase in assembling work, the structure shown in FIGS.
7, the thermal strain can be absorbed, but this method is not always successful in other configurations. In addition, there is a limit to minimizing the dimensional change due to thermal strain. Furthermore, the provision of the spacers 97 increases the cost of parts, and it is difficult to reduce the size of the product.

The present invention has been made in view of such a conventional problem, and an object of the present invention is to provide a method for welding a combination member capable of obtaining high dimensional accuracy in the axial direction.

[0008]

According to the first aspect of the present invention, a hollow member and an insertion member are prepared, and when the insertion member is inserted into the hollow member, the two members are joined to form a combined member. A correction welding process for correcting the distance between the axial ends of the hollow member and the insertion member by partially welding the overlapped portion where the member and the insertion member overlap to provide a partial welded portion. And a method for welding a combination member.

The most remarkable feature of the present invention is to provide a correction welding step of partially welding the overlapped portion to provide a partial welded portion to correct the distance between the axial ends.

Next, the operation of the present invention will be described. Since the contraction stress is generated in the axial direction by providing the partial welded portion, the distance between the ends in the axial direction is contracted (see FIG. 9 described later). Therefore, by appropriately controlling the number and size of the partial welds, the magnitude of the contraction stress can be changed, and the amount of contraction in the axial direction can be controlled. Therefore, it is possible to correct the distance between the ends in the axial direction. Further, according to the present invention, since a separate member such as a spacer is not used, manufacturing costs and material costs are also reduced.

As described above, according to the present invention, it is possible to provide a method for welding a combination member capable of obtaining high dimensional accuracy in the axial direction.

FIG. 12 shows an example of the distance between the axial ends of the combination member. FIGS. 12A and 12B show different combination members. In these, the distance M between the ends in the axial direction is the distance between the ends in the axial direction. The axial direction is a direction parallel to the central axis of the combination member. There are shapes other than the above as combination members,
In that case, the axial end-to-end distance is determined according to the above-described combination member.

In the present invention, it is preferable that the partial weld is provided by welding using a high energy beam. As a result, the partial welded portion can be reliably provided at the target position, so that the axial end distance can be corrected with high accuracy. Note that a laser can be used as the high energy beam.

Next, as in the second aspect of the present invention, it is preferable that the hollow member and the insertion member are joined by a partial weld provided in the correction welding step. Thereby, the manufacturing process can be simplified.
Also, the manufacturing time can be shortened.

Next, it is preferable that the method according to the third aspect of the present invention includes a main welding step of welding the hollow member and the insertion member all around the entire circumference of the overlapped portion. As a result, it is possible to obtain a combined member in which the hollow member and the insertion member are firmly joined and the overlapped portion has excellent airtightness. Further, if the hollow member and the insertion member are joined by the main welding process, the main welding process and the correction welding process can be performed by using a common welding device.

Next, it is preferable that the correction welding step and the main welding step are simultaneously performed by a plurality of welding heads. As a result, the time for the manufacturing process can be reduced.

Next, as in the fifth aspect of the present invention, it is preferable that the insertion member is temporarily fixed by being press-fitted into the hollow member. As a result, the displacement of the welded parts can be reduced, and the working stress is not received only at the welded portion, but can be reduced at the press-fitting surface also in the structure.

Next, as in the sixth aspect of the present invention, it is preferable that the correction welding step is performed by providing at least one set of partial welds at a position that is axially symmetric in the overlapped portion. As a result, it is possible to perform an equal correction symmetrically with respect to the axis, and it is possible to correct the dimension without causing distortion in the axial direction of the combination member.

Next, a measuring step for measuring the distance between the axial ends of the combined member is performed every time the correction welding step is performed, and the distance between the axial ends is set to a desired value. It is preferable to continue the above-described correction welding process until the length becomes the length.

Thus, the correction welding process and the measurement process are alternately performed, and the correction welding process can be performed until a desired length is obtained. In addition, since the measurement and the correction are performed alternately in this manner, the dimensions can be reliably set in an appropriate range. That is, the dimensions of the pre-welding process can be flexibly controlled. In addition, it is also possible to perform the correction welding step at the same time while measuring the distance between the axial ends in real time, for example, without performing the measurement step as an independent step.

Next, as in the invention according to claim 8, a melting amount determining step is performed before performing the correction welding step.
The correction welding step is performed in accordance with the melting amount determined in the melting amount determining step, and the melting amount determining step includes a step of determining a distance between the axial end portions of the combined member before the correction welding and a desired axial end distance. It is preferable to determine the amount of melting from basic data collected in advance according to the difference.

Thus, the welding amount can be set so as to be within a desired distance based on the basic data, and the correction according to the dimensional difference can be reliably performed. Determining the amount of fusion refers to selecting the partial welds that can provide a desired amount of shrinkage by appropriately combining the size, length, position, and number of partial welds.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 A welding method according to an embodiment of the present invention will be described with reference to FIGS. As shown in FIG.
1 and an insertion member 12 are prepared, and the insertion member 12 is inserted into the hollow member 11 to join them by welding to produce a combined member 10. At this time, by providing a spot weld portion 14 as a partial weld portion to an overlap portion 13 where the hollow member 11 and the insert member 12 overlap, the hollow member 11 and the insert member 12 shown in FIG. A correction welding process for correcting the distance L between the axial ends is performed.

The combination member 10 according to this embodiment will be described. The combination member 10 is applied to a valve structure 1 of a fuel injection system in an automobile engine. As shown in FIGS. 1 (a) and 1 (b), the valve structure 1 includes a housing which is a hollow member 11 and the housing. And a body that is an insertion member 12 inserted into the body. A nozzle receiving portion 120 is provided inside the body, and a fuel ejection hole 129 is provided at the center of the nozzle receiving portion 120. Further, the housing is provided with a needle 15 movably arranged in the direction of the arrow A which is the axial direction of the valve structure 10 and having a nozzle portion 150 at the end. The needle 15 is held by a holding member 16 having a spring 160.

Next, the welding devices 2, 20 used in the welding process
Will be described. As shown in FIG. 10, this device has a waveform control device 21, a pulse modulation 22, a power supply 2
3. Oscillator 24. In the present welding process, a CW (continuous) YAG laser is used by the welding device 2, and in the correction welding process, a pulse YAG laser or a CWYAG laser is used by the welding device 20. Through to the welding heads 263, 264. In addition, nozzles 265 and 266 for supplying an assist gas are provided at locations where welding is performed.

Next, a method of manufacturing the fuel injection valve structure using the welding method of the present embodiment will be described in detail. FIG.
As shown in (1), each component is prepared, and the body, which is the insertion member 12, is pressed into the hollow member 11, which is the housing, from the left in the drawing, and the needle 15, the spring 160, and the holding member 16 are pressed from the right in the drawing. Then, as shown in FIG. 3, the overlapping portion 13 of the body and the housing, the holding member 16
Is welded to the overlapping portion 13 of the housing and the housing. This full circumference welding was performed using the welding head 263 of the welding device 2 according to FIG. At this time, the entire circumference was welded with a laser output of 300 W and a processing speed of 12.5 mm.
/ Sec, Ar gas 20 liter / min, frequency 200 Hz,
The test was performed at a duty of 50%. This is the main welding process.

The correction welding step is performed following the main welding step. Prior to the correction welding step, the following steps are performed. That is, the same shape as the housing and body of this example,
A test piece of a combined member prepared by performing the same circumferential joining as above on a member of the same material is prepared. The test piece is spot-welded with a pulsed TAG laser, and the intensity and irradiation time of the laser beam required for correction welding, the number of spot welds and the distance L between the axial ends are determined.
The relationship with the amount of shrinkage was measured. This measurement result is a diagram according to FIG. At this time, the spot welding portion was laser output 20 J / p, pulse width 20 ms, Ar gas 10
It was obtained in liters / minute.

Next, as shown in FIG. 4, a coil 31 is arranged at the center of the outer periphery of the housing. Further, a contact distance sensor 32 having a contact needle 320 is disposed on the left side of the housing. In this state, a current is applied to the coil 31 to turn on and off the magnetic circuit, and the amount of movement of the needle 15 at that time is measured by the contact distance sensor 32. From the amount of movement of the needle 15, the current (after the end of the main welding process) the axial end distance L is measured. From FIG. 9 and the current value of the distance L between the axial ends, the number of spot welds 14 required to obtain a desired L is obtained. In this example, five spot welds were required. Subsequently, the determined number of spot welds 14 is provided in the overlapped portion 13.

The order in which the spot welds 14 are provided will be described. At this time, one set of two spot welds having an axially symmetric positional relationship is provided. As shown in FIG. 7A, after the first spot welded portion (1) is provided at an appropriate position, the spot welded portion (2) is provided so as to be axially symmetric with respect to (1). Thereafter, the spot weld (3) is placed at a position perpendicular to the diameter connecting the positions (1) and (2), and then the spot weld (4) is placed at an axially symmetric position with respect to (3). Is provided.

Thereafter, a spot weld (5) is provided at the center between (1) and (3), and a spot weld (6) is provided at a position axially symmetric with respect to (5). (7) is provided at the center between (3) and (2), and a spot welded portion (8) is provided at a position axially symmetric with respect to (7). In the spot welding, the emission optical section and the laser head in the welding device may be arranged at axially symmetric positions, and the spot welds at the axially symmetric positions may be simultaneously welded. If eight or more spot welds are required, they may be provided in an axially symmetric manner as described above.

The spot welding at this time is performed using the welding apparatus 20 shown in FIG. With respect to the valve structure 1 after the main welding process is completed by the welding head 263, the welding head 2
After the spot weld (1) was provided at 64, this was
And a spot weld (2) is provided. Further, rotation and welding are performed so that a spot where the spot welding portion (3) is to be provided is directly below the welding head 264. Thereafter, a similar procedure is followed to sequentially provide a set of spot welds at axially symmetric positions.

FIG. 8 is a diagram plotting the length of L in the actual main welding step and the correction welding step. Note that Y in the figure indicates a range allowable as the length of L. As shown in the figure, it was found that the length of L gradually decreased by providing the spot weld in the correction welding process, and the length of L reached the allowable range at the fifth point.

The operation and effect of this embodiment will be described. In the present embodiment, a correction welding step for correcting the distance L between the ends in the axial direction of the combination member 10 by providing the spot welding portion 14 with respect to the overlapping portion 13 is provided. By providing the spot weld 140, contraction stress is generated, and as shown in FIGS. 8 and 9, the distance L between the axial ends contracts. Therefore,
The spot welding conditions such as the number and position of the spot welds 140 are appropriately changed according to the correction amount, whereby the magnitude of the contraction stress can be controlled. As described above, control of the contraction amount can be realized. Therefore, the distance L between the axial ends of the combination member 10 can be corrected.

Further, in this embodiment, since a separate member such as a spacer is not used, the manufacturing cost and the material cost can be reduced. In addition, according to the embodiment, a method for welding a combination member capable of obtaining high dimensional accuracy in the axial direction can be obtained. Can be provided.

After the required number of spot welds 14 are provided in the above order, the coil is installed again to determine the current length of L from the amount of movement of the needle, and the length of L is reliably allowed. The correction welding process and the measurement of L can be repeatedly performed until it falls within the range.

Embodiment 2 As shown in FIG. 11, this embodiment describes a case where the correction welding step and the main welding step are performed simultaneously. As the welding device, the device according to the first embodiment shown in FIG. 10 is used. However, in this example, the two welding heads 263 and 264 are used.
Use at the same time. If it can be controlled at one point, it is possible.

As shown in FIG.
Is rotated in the direction of the arrow V shown in FIG. By rotating the combination member 10, the main welding process is performed by the welding head 263, and spot welding is performed by the welding head 264 from the portion where the main welding process has been completed. At this time, the correction welding step can be performed while measuring the length of L in real time using the contact distance sensor described in the first embodiment for the distance between the axial ends. Other details are the same as those of the first embodiment, and have the same functions and effects as those of the first embodiment.

Third Embodiment In the first and second embodiments, the distance between the ends in the axial direction is corrected by the spot welds. However, even in the correction welding step, a partial weld having a predetermined length in the circumferential direction can be provided at the overlapped portion of the hollow member and the insertion member using a CW-YAG laser. Also in this case, for example, the amount of fusion required for correction is determined in advance by calculation,
It is preferable to divide it into two equal parts and three equal parts to provide a partial weld at an axially symmetric position.

[Brief description of the drawings]

FIG. 1A is a plan view of a valve structure according to a first embodiment, and FIG.

FIG. 2 is a development explanatory view of a valve structure according to the first embodiment.

FIG. 3 is a perspective view of a valve structure according to the first embodiment.

FIG. 4 is an explanatory diagram of measurement for a valve structure in the first embodiment.

FIGS. 5A and 5B are a cross-sectional view and a vertical cross-sectional explanatory view of a valve structure provided with a spot weld according to the first embodiment.

FIG. 6 is an explanatory diagram of measurement for a valve structure provided with a spot weld in Embodiment 1;

FIGS. 7A and 7B are explanatory diagrams of (a) the order of providing spot welds with respect to a valve structure in the first embodiment, and (b) the distance L between axial ends of a combination member in the valve structure;
FIG.

FIG. 8 is a diagram showing a change in L in a main welding step and a correction welding step in the first embodiment.

FIG. 9 is a diagram showing the relationship between the number of spot welds in a test piece and the total shrinkage in the first embodiment.

FIG. 10 is an explanatory diagram of a welding device used in a main welding process and a correction welding process according to the first embodiment.

FIG. 11 is an explanatory diagram of a method for simultaneously performing a main welding step and a correction welding step in a second embodiment.

FIG. 12 is an explanatory view showing a distance between axial ends in the present invention.

13 (a) is a plan view and FIG. 13 (b) is a vertical sectional view of a conventional valve structure.

[Explanation of symbols]

 1. . . 9. Valve structure, . . Combination member, 11. . . Hollow member, 12. . . 12. insert member; . . 13. superposition section; . . Spot welds,

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // F02M 61/16 F02M 61/16 P B23K 101: 04 B23K 101: 04 (72) Inventor Yoshinori Omi Aichi 1-1-1 Showa-cho, Kariya-shi, Japan Inside Denso Corporation (72) Inventor Eiji Iwanari 1-1-1, Showa-cho, Kariya-shi, Aichi Prefecture F-term in Denso Corporation 3G066 BA51 BA54 BA61 CC01 CC14 CD04 DC03 4E068 BF00 BG02 CA14 CC06 CD02 DA02 DA15

Claims (8)

[Claims] 1. A method of preparing a hollow member and an insertion member, and joining the two members in a state where the insertion member is inserted into the hollow member to form a combined member, wherein the hollow member and the insertion member overlap each other. A method for welding a combination member, comprising a correction welding step of correcting a distance between axial ends of the hollow member and the insertion member by partially welding a portion to provide a partial weld portion. . 2. The method according to claim 1, wherein the hollow member and the insert member are joined by a partial weld portion provided in the correction welding step. 3. The method for welding a combination member according to claim 1, further comprising a main welding step of welding the entire periphery of the hollow member and the insertion member over the entire circumference of the overlapped portion. 4. The method according to claim 3, wherein the correction welding step and the main welding step are simultaneously performed by a plurality of welding heads. 5. The method according to claim 1, wherein:
A method for welding a combined member, wherein the insertion member is temporarily fixed by being press-fitted into the hollow member. 6. The method according to claim 1, wherein:
The method for welding a combination member, wherein the correction welding step is performed by providing at least one set of partial welds at positions that are axially symmetric in the overlapped portion. 7. The method according to claim 1, wherein:
Each time the correction welding step is performed, a measurement step of measuring a distance between the axial ends of the combined member is performed, and the correction welding step is continued until the distance between the axial ends reaches a desired length. Welding method for combination members. 8. The method according to claim 1, wherein:
Before performing the correction welding step, a melting amount determination step is performed, and the correction welding step is performed according to the melting amount determined in the melting amount determination step. A method for welding a combination member, comprising: determining a melting amount from basic data collected in advance according to a difference between an end-to-end distance and a desired axial end-to-end distance.