JPH07102468B2 - Electron beam welding method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is designed such that after a second member such as a gear of a first member such as a shaft is press-fitted and fitted, a space between the first and second members is provided. By irradiating an electron beam along the exposed joint,
TECHNICAL FIELD The present invention relates to an electron beam welding method that is joined to each other.

[Conventional technology]

Conventionally, for example, a very strong coupling is required for joining a shaft and a gear that form a part of an automobile transmission or the like.Therefore, after the center hole of the gear is press-fitted to the shaft, both of them are joined. Further welding of the joint is performed, and electron beam welding is used as the welding means.

[Problems to be Solved by the Invention]

By the way, in the case of this electron beam welding, a narrow electron beam irradiation portion is remarkably heated to a high temperature, so that heat distortion, cracks and the like occur in the member, which causes so-called weld cracking.

Therefore, as a countermeasure against this, as shown in FIG. 6, it is known to provide an annular groove (groove hole) 3 over the entire circumference in the middle of the joint surface between the shaft 1 and the gear 2.

However, when the groove hole 3 is provided in this way, air remains in the groove hole 3, and therefore, when electron beam welding is performed in a vacuum, the pressure difference between the inside of the groove hole 3 and the outside is shown in FIG. As described above, the gas is often blown out as shown by an arrow a, which makes it difficult to perform good welding over the entire joint surface.

Further, in order to eliminate the above-mentioned gas jet, as shown in FIG. 7, a gas vent hole 4 communicating with the groove hole 3 and opening in the direction of the central hole of the shaft 1 is provided so that the generated gas is indicated by the arrow b. It is also considered to pull out like.

However, in this case, as shown in FIG. 8, if the spatter 5 (so-called flowable substance) generated by electron beam welding remains attached inside the slot 3, the welded part will be damaged. , The spatter 5 may come out of the gas vent hole 4 during driving of the vehicle.
There is a problem that it causes a secondary trouble.

The present invention has been made to solve such a problem, and in which a groove hole is provided over the entire circumference in the middle of the joint surface between the first member and the second member in order to prevent welding cracks,
An object of the present invention is to provide an electron beam welding method in which the groove hole is completely sealed after the welding is completed while surely performing degassing during welding.

[Means for Solving the Problems]

In order to achieve the above-mentioned object, the electron beam welding method of the present invention is such that the inner periphery of the second member is press-fitted onto the outer periphery of the first member, and in this press-fitted state, the first member and An annular groove is formed inwardly of the exposed joint portion formed between the second member and the exposed joint portion, and
A first step in which a gap that communicates the annular groove with the outside of the exposed joint is formed over the entire circumference of the exposed joint, and the exposed joint that is the opening portion of the gap. By irradiating an electron beam along the first member and the second member.
And a second step of joining the above-mentioned members by electron beam welding.

[Work]

In the above-described electron beam welding method of the present invention, when electron beam welding the first member and the second member, first,
At the first stage, the second member is press-fitted into the first member.
Then, in this press-fitting fitted state, an annular groove is formed over the entire circumference at the joint portion between both members inward of the exposed joint portion of both members, and from the annular groove to the exposed joint portion, A gap is formed over the entire circumference at the joint portion between the first and second members. After that, in a second step, the two members are joined to each other by irradiating with an electron beam along the exposed joint between the first and second members. At this time, the gas generated by the electron beam welding is discharged to the outside from the gap where welding is not yet performed as the welding progresses, so that no gas remains in the annular groove.
Further, after the welding is completed, the gap is completely eliminated and the annular groove is completely closed.

〔Example〕

An electron beam welding method according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing a joint portion of its first and second members, and FIG. 2 is a II direction of FIG. FIG. 3 is an end view as seen from above, FIG. 3 is an exploded cross-sectional view showing a state before joining the first and second members, and FIG. 4 is an enlarged view of a main part of the joining portion of the first and second members. 5 is an enlarged partial sectional view of the welding end portion, and FIG.
In FIG. 5, the same reference numerals as those in FIGS. 6 to 8 indicate almost the same parts.

In this embodiment, as an example, a case where a shaft (first member) and a gear (second member) that form a part of a transmission mounted on an automobile are joined together will be described.

Now, as shown in FIG. 3, a reduced diameter end portion 1a is formed at the end portion of the shaft 1 as the first member, and a reduction gear of the shaft 1 is provided at the gear 2 as the second member. A center hole 6 that can be fitted into the radial end portion 1a is formed. Therefore, the reduced diameter end portion 1a of the shaft 1
When the center hole 6 of the gear 2 is press-fitted into the shaft end face direction,
As shown in FIGS. 1 and 2, the two are integrally connected.

By the way, in the middle of the joint between the shaft 1 and the gear 2, that is, in the portion inward of the exposed joint 7 in the axial direction, an annular groove (groove) for preventing welding cracks due to electron beam welding over the entire circumference thereof. Hole 3 is provided, and both sides 1 and 2 at the time of fitting are provided on the entire circumference between the groove 3 of this joint and the exposed joint 7.
Both members 1 and 2 are processed so that a narrow gap, that is, a gap 8 of about 0.1 mm is formed between the two.

Next, a description will be given of the joining process of the both members 1 and 2. First, as shown by an arrow c in FIG. 3, the shaft 1 and the gear 2 are relatively moved so that the reduced diameter end portion 1a of the shaft 1 has a gear. The two center holes 6 are press-fitted and fitted (first step).

In such a fitted state, both members 1 and 2 are press-contacted to the inside of the groove 3 in the axial direction, and the outside of the groove 3 in the axial direction (end face side)
A narrow gap 8 is formed as shown in FIG.

After that, electron beam irradiation is performed toward the exposed bonding portion 7 which is the opening portion of the gap 8 as indicated by an arrow d in FIG. 4, and this irradiation is sequentially performed in the circumferential direction over the entire circumference of the bonding surface. Let's proceed. As a result, as shown in FIG. 5, the welded portion 9 is applied to the entire circumference, and the shaft 1 and the gear 2 are integrally connected (second step).

In this case, since the gas generated by the electron beam welding is discharged to the outside from the gap 8 where welding is not yet performed, the gas does not remain in the groove hole 3 as the welding progresses. Therefore, it is not necessary to provide the above-mentioned gas vent hole 4 (see FIGS. 7 and 8) for releasing the gas in the slot 3.

Further, after the welding is completed, the gap 8 disappears completely, and the groove 3
Is completely closed, so there is no fear that the spatter 5 (see FIG. 8) remaining in the groove 3 will move to the outside at a later date.

In the above embodiments, the first member is a round rod-shaped shaft,
Although the gear having a round hole is described as an example of the second member, the second member is press-fitted into the first member, and then the electronic component is formed along the exposed joint between the first and second members. As long as they are to be joined together by irradiating the beam, the shape of the first and second members, etc.
It goes without saying that the present invention can be applied.

〔The invention's effect〕

As described in detail above, according to the electron beam welding method of the present invention, the inner periphery of the second member is press-fitted onto the outer periphery of the first member, and in this press-fitted state, the first member is An annular groove is formed inwardly of an exposed joint formed between the exposed joint and the second member, and
A first step in which a gap that communicates the annular groove with the outside of the exposed joint is formed over the entire circumference of the exposed joint, and the exposed joint that is the opening portion of the gap. By irradiating an electron beam along the first member and the second member.
And the second step of joining the member of No. 2 by electron beam welding, the gas generated in the annular groove due to the electron beam welding is immediately generated outside the gap where welding is not yet performed. Therefore, the gas accumulated in the annular groove will not be ejected and a defective welding portion will not be generated, whereby good welding can be performed over the entire joint.

In addition, since the ejection of gas from the welded portion of the exposed joint is prevented, it is not necessary to provide a gas vent hole or the like for venting the gas in the annular groove to the other side, and the spatter remaining in the annular groove can be removed at a later date. , It is possible to eliminate the occurrence of secondary troubles caused by expanding to the outside.

[Brief description of drawings]

1 to 5 show an electron beam welding method as an embodiment of the present invention. FIG. 1 is a sectional view showing a joint portion of first and second members thereof, and FIG. 2 is an end view as seen from the II direction, FIG. 3 is an exploded cross-sectional view showing a state before the first and second members are joined, and FIG. 4 is a main part of the joined portion of the first and second members. FIG. 5 is an enlarged partial sectional view showing the welding end portion, and FIG. 5 is an enlarged partial sectional view showing the welding end portion. FIG. FIG. 7 is an enlarged partial sectional view, FIG. 7 is an enlarged partial sectional view of a conventional electron beam welded portion having a groove and a gas vent hole, and FIG. 8 is a partial enlarged sectional view of a portion VIII in FIG. 7. is there. 1 ... Shaft (first member), 1a ... Reduced end portion, 2 ... Gear (second member), 3 ... Annular groove (groove hole), 6 ... Center hole, 7 ... Exposed Joints, 8 ... gaps, 9 ... welds.

Claims (1)

[Claims] 1. An inner periphery of a second member is press-fitted onto an outer periphery of a first member, and in this press-fitted state, the first member and the second member
An annular groove is formed inside the exposed joint formed between the exposed groove and the member, and the annular groove is communicated with the outside of the exposed joint. A first step in which a gap to be formed is formed over the entire circumference of the exposed joint portion, and by irradiating an electron beam along the exposed joint portion which is the opening portion of the gap, And a second step of joining the second member and the second member by electron beam welding.