JP3535592B2 - Propeller shaft balance weight - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a balance weight mounted on a propeller shaft to cancel its imbalance. [0002] A propeller shaft is interposed between a transmission of a vehicle and a differential, and transmits the output of an engine to driving wheels. If the rotational balance of the propeller shaft is out of order, the propeller shaft will not rotate smoothly, and vibration noise and the like will be generated. Therefore, a balance weight is attached to the outer peripheral surface of the propeller shaft. This balance weight is attached to the outer peripheral surface of the propeller shaft by MIG spot welding or the like (Japanese Patent Publication No. Hei 4-31442). In recent years, in order to reduce the weight of a vehicle, it has been promoted to change the propeller shaft from iron to aluminum. On the other hand, in order to effectively balance a lightweight aluminum propeller shaft, an iron balance weight having a large specific gravity is used. FIG. 3 shows a conventional balance weight attached to such an aluminum propeller shaft.
As shown in the figure, the balance weight a is formed in a rectangular plate shape, and a through hole b for forming a welded portion is provided at a substantially central portion thereof. Here, the through-hole b is circular. Further, the balance weight a is attached to the outer peripheral surface of the propeller shaft, particularly to the pipe portion, and is therefore curved in a round shape according to the shape of the outer peripheral surface. As shown in FIG. 4, when a balance weight a is attached, the balance weight a is applied to a predetermined position of a pipe portion c of a propeller shaft, and a welding head is inserted into a through hole b. Mig spot welding is performed with d approaching. However, if the center d _c of the welding head d is shifted with respect to the center b _c of the hole b, dissolved peripheral portion of the hole b of the balance weight a, it will be biased also padding of weld metal e same time, good A weld cannot be obtained, resulting in a decrease in strength or reliability. In particular, as shown in the figure, when the balance weight a is to be vertically mounted on the side of the pipe portion c, the molten metal flows down on the surface of the balance weight a, so that the defect becomes remarkable. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a balance weight of a propeller shaft capable of obtaining a good weld regardless of a displacement of a welding head. Is to do. [0008] To achieve the above object, the present invention provides an iron balance weight which is attached to the outer peripheral surface of an aluminum propeller shaft by welding, wherein a weld is formed at the center. And a slit extending from the through hole to allow molten metal to enter. When the position of the welding head is shifted, welding is performed at a position offset from the center of the hole. At this time, the molten metal also enters the slit and flows uniformly in the through hole and the slit. And stick. An embodiment of the present invention will be described below with reference to the accompanying drawings. [0011] As shown in FIG.
Is formed in a rectangular shape using an iron plate having a predetermined thickness. Further, the balance weight 1 is curved in a round shape along the up-down direction of the drawing so that the back surface portion 2 faces inward,
Thus, the aluminum propeller shaft 3 (see FIG. 2)
Is brought into contact with the outer peripheral surface without any gap. In the center of the balance weight 1, a through hole 5 penetrating from the front surface portion 4 to the back surface portion 2 is formed to form a weld. The through hole 5 has a circular shape here, and its center is offset slightly above the center of the balance weight 1. The balance weight 1 is provided with a linear slit 6 extending downward from the lower end of the through hole 5 along the center position in the left-right direction. The slit 6 has a predetermined width w, extends from the lower end surface of the through hole 5 to the lower end surface 7 of the balance weight 1, and is formed through the front surface portion 4 and the back surface portion 2 of the balance weight 1 like the through hole 5. Is done. Thus, the through hole 5 and the slit 6 form a keyhole shape. The balance weight 1 thus formed
When attaching the propeller shaft 3 to the propeller shaft 3, as shown in FIG. Abut. Then, while maintaining that state, a welding head (not shown) is brought close to perform MIG spot welding. In particular, here, it is assumed that the propeller shaft 3 is held so that the pipe portion 8 is horizontal, and the balance weight 1 is attached to the side outer peripheral surface 9 of the pipe portion 8. At the time of welding, basically, the center of the welding head is made to coincide with the center of the through hole 5, the filler material discharged from the welding head, and the peripheral portion of the through hole 5 and the propeller shaft 3 which are melted by this. The molten metal including the outer peripheral surface 9 is evenly fixed inside the through hole 5 and the slit 6 and fixed. However, even if the welding head is misaligned,
The slit 6 enables good welding as described above.
That is, when the center position of the welding head is shifted downward from the center position of the through hole 5, the filler material from the welding head passes through the slit 6 and collides with the outer peripheral surface 9 of the propeller shaft 3, thereby causing the penetration. Melting around the hole 5 is greatly reduced. In addition, since the filler material or the molten metal also enters the through holes 5 and the slits 6, overflow or buildup on the surface portion 4 is greatly reduced, and the welded portion 10 having a good and uniform thickness is formed. Can be formed. Here, the flow of the molten metal downward from the slit 6 can be prevented by optimizing the width w of the slit 6. When the welding head is shifted upward or left and right, there is no problem because the molten metal flows sequentially downward. In particular, since the welded portion 10 is formed also at the slit 6, there is an advantage that the welding strength can be greatly improved by increasing the welding area, and high reliability can be secured. The balance weight having the above structure can be modified in various ways other than the above embodiment. For example, a plurality of slits can be formed or a radial shape can be formed. However, at this time, it is necessary to change the extension length of the slit so that the balance weight is not divided.
It is also possible to make the through hole into a shape other than a circular shape, and to make the slit into a shape other than a linear shape. In this specification, the propeller shaft includes not only a pipe portion but also yoke portions attached to both ends thereof. Therefore, the balance weight may be attached not only to the pipe part but also to the yoke part. As described above, according to the balance weight of the propeller shaft according to the present invention, the following excellent effects can be exhibited. (1) A good weld can be obtained irrespective of the displacement of the welding head. (2) High reliability can be secured by greatly improving the welding strength.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a balance weight of a propeller shaft according to the present invention, wherein (a) is a side view and (b) is a front view. FIGS. 2A and 2B show a mounting state of a balance weight, wherein FIG. 2A is a side view and FIG. 3A and 3B show a conventional balance weight, wherein FIG. 3A is a side view and FIG. 3B is a front view. FIG. 4 is a side view showing a mounting state of a conventional balance weight. [Description of Signs] 1 Balance weight 3 Propeller shaft 5 Through hole 6 Slit 9 Outer peripheral surface 10 Welded part

Claims (1)

(57) [Claims 1] In an iron balance weight which is attached to the outer peripheral surface of an aluminum propeller shaft by welding, a through hole for forming a welded portion is provided at a central portion. A balance weight for a propeller shaft, wherein a slit is provided to extend from a through hole and allow molten metal to enter.