JP2519513B2 - Electronic beam welding method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a first part such as a shaft and a second part such as a gear.
The invention relates to an electron beam welding method in which members are joined together by press-fitting and fitting and then irradiating with an electron beam along the exposed joint between the first and second members.

[Conventional technology]

Conventionally, as means for fitting and binding a shaft and a gear forming a part of a transmission of an automobile,
As shown in the figure, after the center hole of the gear 3 is press-fitted into the joint portion (reduced diameter end portion) 2 with the gear 3 at the end portion of the shaft 1 from the end face direction, the exposed joint portion which is the joint end face. (Electron beam irradiation part) The electron beam is radiated toward the joint from 5 to weld up to a certain depth h1 of the joint, and both the shaft 1 and the gear 3 are integrated into a strong joint. Is being taken.

[Problems to be Solved by the Invention]

However, as described above, in the case where electron beam welding cannot be performed over the entire depth H of the joint portion of both members, that is, in other words, in the case where the joint portion is electron beam welded only up to a certain depth h1, The welded part shrinks as the member once melted by electron beam irradiation solidifies (this shrinkage is, for example, about 0.1 to 0.3 mm)
Then, as shown by the chain line in FIG. 5, the outer shape of the member may be deformed into a tapered shape after welding. Therefore, it is necessary to correct and process the tapered shape after welding, but particularly when the member to be welded is a gear or the like, the shape is complicated, and there is a problem that the processing is extremely difficult.

The present invention has been made in order to solve such a problem, and is a welded part after welding for a part that cannot be electron beam welded over the entire depth of the joint between the first and second members. It is an object of the present invention to provide an electron beam welding method capable of eliminating the need for correction processing of deformation due to shrinkage of steel.

[Means for solving the problem]

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 A first step in which the interference in the electron beam irradiation part formed in a part of the fitting part between the second member and the second member is larger than the interference in the part other than the electron beam irradiation part; Irradiating an electron beam to a portion having a large interference formed in a part of a fitting portion between the first member and the second member, and the first member and the second member. And a second step of joining the members.

[Work]

In the electron beam welding method of the present invention described above, when the first member and the second member are electron beam welded, first, the second member is press-fitted into the first member in the first stage. . Then, in this press-fitting fitted state, the tightening margin in the electron beam irradiation part formed in a part of the joint between the first member and the second member is larger than that in the part other than the electron beam irradiation part. Is also becoming larger.

After that, in the second stage, by irradiating the portion having a large interference formed in a part of the fitting portion of the first member and the second member with the electron beam, the space between the two members is increased. The welding to the intermediate depth portion of the joining portion is performed over the entire circumference to join the first member and the second member.

〔Example〕

An electron beam welding method as one embodiment of the present invention will be described below with reference to the drawings.
Fig. 2 is an exploded sectional view showing the state before joining the members of Fig. 2, Fig. 2 is a sectional view showing the joined state of the first and second members, and Fig. 3 is a state showing the joined first and second members. FIG. 4 is a cross-sectional view showing the state after welding the first and second members in correspondence with FIG. 2, and FIG. The same reference numerals as those in FIG. 5 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 FIGS. 1 and 2, the shaft 1 is provided at its end with a reduced diameter end 2 for joining gears, and a gear 3 is press-fitted into a center hole 4 thereof. Then, they are joined as shown in FIG.

In this case, at the portion corresponding to the depth h1 of the electron beam welding at the joint between the members 1 and 2, it is set so as to be in a strong press-fit state (for example, the tightening margin is about 0.2 to 0.5 mm). Depth corresponding to the depth h1 or more of
h2), it is set so that it is in a light press-fit state (for example, the tightening margin is about 0.1 mm or less). As shown in FIG. 1, this is done by processing so that the upper portion (the portion near the end) of the center hole 4 of the gear 3 becomes an inversely tapered hole in which the diameter becomes slightly inward. It can be realized.

Then, in order to press fit the gear 3 to the shaft 1, it is necessary to perform strong press-fitting.
For example, by heating to a maximum of about 250 ° C and shrink fitting, or conversely, by using liquid nitrogen on the shaft 1, for example, -196 ° C.
By adopting a means such as cooling to a certain degree and cooling and fitting, it is possible to press fit the gear 3 to the shaft 1 without damaging the joint portion such as scoring and peeling.

When the shaft 1 and the gear 3 are press-fitted in this manner, the second
As shown slightly exaggerated in the figure, the upper part of the fitting part extends slightly outward.

That is, in the press-fitting fitting portion of the shaft 1 as the first member and the gear 3 as the second member, the tightening allowance at the exposed joint portion (electron beam irradiation portion) 5 is not the allowance allowance other than the electron beam irradiation portion 5. By being formed larger than
The vicinity of the electron beam irradiation portion 5 of the gear 3 is pushed outward and deformed (first stage).

In this state, electron beam irradiation is performed over the entire circumference toward the exposed joint portion 5 between the members 1 and 3. This allows
The strong press-fitting portions of the shaft 1 and the gear 3 are melted and solidified again to form the welded portion 6, and the members 1 and 3 are integrally joined as shown in FIG. Stage).

Then, due to the solidification after the melting, the outer shape of the gear 3 is sucked and contracted inward. In this case, both members 1 and 3 generated when the gear 3 is press-fitted onto the shaft 1 in the state before welding.
Among the joints between the two, the joint h1 corresponding to the welding depth is in a state of strong press-fit with a larger interference than the other non-welded joints h2, and the contact between the members 1 and 3 The condition is uneven. In other words, these members 1 and 3 are deformed in an inverse taper shape so that the portion contracted after the welding is slightly expanded outward before the welding, and as a result, due to the solidification after the melting, the gear 3 is deformed.
When the outer shape of the is sucked and contracted inward, the initially desired outer shape of the gear is obtained. As a result, it becomes unnecessary to modify the outer shape of the gear after welding.

In other words, as the electron beam irradiation unit 5 contracts and deforms, the portion of the gear 3 extruded in the outer peripheral direction contracts and deforms, so that the external shape of the gear 3 after electron beam welding becomes the first member 1. The desired outer shape before mating,
It is not necessary to correct the outer shape of the second member 3 after welding.

In order to realize a state of strong press-fitting in the welded portion of the above-described joint, the shaft 1 side may be processed by thickening the corresponding reduced-diameter end portion of the shaft 1, or Both members may be processed corresponding to each.

Further, although the shaft is used as the first member and the gear is used as the second member as an example, the second member is press-fitted into the first member, and then exposed between the first and second members. By irradiating an electron beam along the joint, welding is performed over the entire circumference up to the joint corresponding to the required welding depth among the joints between the two members, so that they are joined to each other. It goes without saying that the present invention can be applied to such a case.

〔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 And a second step in which a tightening margin in the electron beam irradiation section formed in a part of the fitting section between the second member and the second member is larger than a tightening margin in a portion other than the electron beam irradiation section. And irradiating an electron beam to a portion having a large interference formed in a part of a fitting portion between the first member and the second member, and the first member and the second member. The second step of joining the second member and the second member allows the electron beam welding to shrink and deform the outer shape of the second member.
The outer shape of the second member after welding can be adapted to an initially desired outer shape, which eliminates the need to modify the outer shape of the second member after welding as in the conventional case, and as a result, after welding There is an advantage that it is easy to improve the finishing accuracy of the member.

Further, by eliminating the work of modifying the outer shape of the second member again after the welding is completed,
There is also an advantage that the number of steps and the manufacturing cost can be reduced.

[Brief description of drawings]

1 to 4 show an electron beam welding method as one embodiment of the present invention, and FIG. 1 is an exploded sectional view showing a state before joining the first and second members, FIG. Is the first and second
Sectional view showing the joined state of the members of FIG. 3, FIG.
FIG. 4 is a cross-sectional view showing the state after the members 1 and 2 are welded together, and FIG. 4 is a sectional view corresponding to FIG. FIG. 5 is a cross-sectional view showing a state after joining the first and second members in the conventional example. 1 ... Shaft (first member), 2 ... Reduced end portion, 3 ... Gear (second member), 4 ... Center hole, 5 ... Exposed joint (electron beam irradiation portion), 6 …… Welded area, h1 …… Welding depth.

Claims (1)

(57) [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
A first step in which the interference in the electron beam irradiation part formed in a part of the fitting part between the member and the member is larger than the interference in the part other than the electron beam irradiation part; The first member and the second member are irradiated with an electron beam to irradiate the portion having a large interference formed in a part of the fitting portion between the first member and the second member. And a second step of joining, the electron beam welding method.