JPH0698384B2 - Manufacturing method for banjyo type axle tube - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a Banjo type shaft tube.

(Prior Art) Conventionally, manufacturing of a Banjo type axle tube has been performed by referring to FIG.
As shown in (c), first, a half-split axle tube 1 including a half-split drum section 3a having a square cross section and a half-split tube section 4a having a round cross section is formed by press drawing (a). ,
Subsequently, the end face surplus portion 5 is cut to obtain a half-divided axle tube 2 having a predetermined size and shape (b), and then the two half-divided axle tubes 2, 2 are joined and welded along the mating surface. However, a method of forming the drum portion 3 and the tube portion 4 which are integral with each other has been adopted.

The method of manufacturing one member by combining the halves as described above is also used in other fields, for example, manufacturing of elbows (Japanese Patent Laid-Open No. 56-6725).

(Problems to be Solved by the Invention) However, according to the above-described conventional manufacturing method, when the half-split axle tube 1 is molded, the half-split tube portion 4a is spring-backed as shown in FIG. , 4b in the figure is slightly deformed. This amount of deformation l is the half tube part
The deformation amount 1 increases as the length of the tube portion 4a increases, depending on the length of the tube portion 4a.

Then, when the end cutting process is performed on the half-split axle tube 1 thus deformed, as shown in FIG. 5, a surplus portion 5 ′ to be cut off with respect to the end cutting line L is formed in the longitudinal direction. As a result, the axle tube thus obtained has a dimension (diameter) d ′ of the tube portion 4 different from the required dimension d, as shown in FIGS. 6 (a) and 6 (b). However, there is a problem that a predetermined quality cannot be secured. 6 (a) shows an axle tube with a large tube length, and FIG. 6 (b) shows an axle tube with a small tube length. It is clear that the larger the tube length, the greater the deformation. is there.

In solving the above problem, it is effective to straighten the half-split tube 4a (4b) prior to the end cutting process (Fig. 1 (b)). In fact, many measures to incorporate the straightening process are adopted. ing.

By the way, most of the Banjo type axle tubes of this type are produced for trucks, and the types thereof are increasing along with the diversification of truck vehicle types in recent years. However, in response to such an increase in types, changing the shape of the axle tube each time is too costly in view of the reality of truck production, which is not so large in production volume as passenger cars. Therefore, in general, the shape of the drum portion 3 is generally accommodated by changing the length of the tube portion 4, and this has an advantage that a common molding die can be used.

However, the length of the tube portion 4 has a great influence on the amount of deformation due to springback as described above, and therefore, when the correction step is incorporated, it becomes difficult to correct the same shape. After all, a dedicated straightening die must be prepared for each type of Banjo type axle tube, and there is a problem that the merits of using the common shaping die are offset.

The present invention has been made in view of the above conventional problems,
An object of the present invention is to provide a method for manufacturing Banjo type axle tubes having different lengths with high accuracy without a special straightening process.

(Means for Solving Problems) In order to solve the above problems, the present invention forms a half-split axle tube by drawing and then forms a half-split tube portion of the half-split axle tube. Elastically deform to a normal shape and perform end cutting to obtain a half-split axle tube, then join the two half-split axle tubes, and elastically deform the tube part to a normal shape, then weld the mating portion. It is characterized in that it is configured to.

(Operation) In the manufacture of the Banjo type axle tube having the above-mentioned configuration, since the half-divided tube portion of the half-divided axle raw tube is elastically deformed into a regular shape and the end cutting is performed, the desired end cutting line is performed along the line. The extra thickness can be cut off, and the regular half-tube shape can be secured. Deformation due to springback remains even with this end cutting process, but in the subsequent welding process, the tube part formed by combining the two half-split axle tubes is elastically deformed into a regular shape and welded and integrated, so springback The forces are balanced and the deformation is corrected spontaneously, which makes it possible to manufacture a Banjo type axle tube with excellent dimensional accuracy.

(Example) Hereinafter, an example of the present invention is described based on an accompanying drawing.

FIGS. 1 (a) and 1 (b) show an execution mode of the end cutting according to the present invention. In the figure, 11 is a die fixed on a lower mold (not shown), 12 is a pad held by an upper mold (not shown) via an elastic member (urethane rubber, gas spring, etc.) 13, and 14 is a pad. A movable cam slidably mounted on the lower mold, and a fixed cam 15 mounted on the upper mold. The die 11 is a half-split axle tube 1 that has been molded into a regular shape.
Has a seat portion 11a which can be fitted into the upper end of the die, while the pad 12 has a half-divided tube portion 4a of the half-split axle tube 1 for the die 11.
It has projections 12a and 12b that can be pressed against the seat portion 11a.

As a result, first, the half-split axle blank tube 1 that has undergone the press drawing is set on the seat portion 11a of the die 11, and then the upper die is lowered. Then, the projections 12a and 12b of the pad 12 press the half-divided tube portion 4a against the seat portion 11a of the die 11, thereby correcting the deformation caused by the spring back of the tube 4a caused by the previous drawing process. . After that, the fixed cam 15 pushes the movable cam 14 due to the lowering of the upper mold,
The movable cam 14 slides to the die 11 side, and the extra thickness portion 5 is cut along the end cutting line L.

Thus, the load that presses the half-divided tube portion 4a is only sufficient to elastically deform the tube portion, and therefore, after unloading, the tube portion 4a returns to the deformed state due to the spring back.

FIG. 2 shows an execution mode of the welding process performed after the end cutting process. In the figure, 21 is a base 22
A reference gold fixed on the upper side, 23 is a clamper arranged so as to face the reference gold 21, and 24 is a cylinder (air or hydraulic pressure) for supporting the clamper 23. A clamp device for positioning and fixing the tube 2 is configured. The reference gold 21 and the clamper 23 are the protrusions 21a, 21b and 23 corresponding to the protrusions 12a, 12b (FIG. 1) on the pad 12.
The protrusions 12a and 12b have the same positional relationship with the protrusions 12a and 12b. That is, the half-split axle tube 2 is fixed at the same position as the portion fixed at the time of end cutting.

As a result, first, the two half-split axle tubes 2 are placed together on the protrusions 21a, 21b of the reference gold 21, and then the clamper 23 is lowered by the operation of the cylinder 24, so that the two half-split axle tubes 2, 2
To fix. This fixing corrects the deformation caused by the spring back caused by the previous drawing process and obtains a welding line 25 with almost no gap.By performing welding along this welding line 25, the integrated Banjo-type axle A tube 3 (Fig. 3 (c)) is obtained.

By the above welding, the springback forces existing in the two half-split axle tubes 2, 2 are balanced, and as a result, the clamper
Even if 23 is released, the resulting tube portion 4 of the axle tube 3 is corrected spontaneously and finished into a regular shape.

(Effects of the Invention) Since the present invention is configured and operates as described above, it has an effect that a Banjo-type axle tube having excellent dimensional and shape accuracy can be manufactured without a separate correction step. Moreover, not only the straightening process can be omitted, but also the process can be simplified and the number of devices can be reduced, and it is also possible to manufacture Banjo type axle tubes with different lengths by the same molding die, which improves productivity and reduces manufacturing cost. The effect was produced.

[Brief description of drawings]

1 (a) and 1 (b) are schematic views showing an execution mode of the end cutting process according to the present invention, and FIG. 2 is a schematic view showing an execution mode of the welding process according to the present invention, 3 (a) to 3 (c) are perspective views showing a general method for manufacturing a Banjo type axle tube in the order of steps, FIG. 4 is a perspective view showing a deformed state caused by drawing, and FIG. 5 is caused by the deformation. 6 (a) and 6 (b) are explanatory views showing an example of a defective product due to the deformation. 1 …… Half-split axle tube 2 …… Half-split axle tube 4a …… Half-split tube

Claims (1)

[Claims] 1. A method of manufacturing a banjo type axle tube having a drum portion and tube portions extending to both sides of the drum portion, the method comprising forming a half-split axle tube by drawing and then forming the half split axle tube. The half-divided tube part of the split axle shaft tube is elastically deformed into a regular shape and subjected to end cutting to obtain a half-divided axle pipe, after which the two half-split axle pipes are combined and the tube portion is formed into a regular shape. A method of manufacturing a banjo-type axle tube, which comprises elastically deforming and welding the mating portion.