JP2820760B2 - Manufacturing method of deformed tube - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a modified tube comprising a hollow male shaft and a female shaft which are fitted so as to slide in the axial direction.

(Prior art and its problems) This type of deformed tube is used, for example, in a joint assembly consisting of two universal joints.
Lemon-shaped or star-shaped ones are used so that the male shaft is inside the female shaft and does not rotate around the axes with each other.

In order to manufacture these deformed tubes, a metal tube is mechanically formed, or a male shaft and a female shaft are separately manufactured by broaching or the like, and the male shaft and the female shaft are slidably fitted. The gap was corrected manually. Therefore, not only does it take a lot of time to manufacture, but also there is a lot of play between the male shaft and the female shaft, generating noise during work, easy to seize, seizure, and the transmission efficiency of the universal joint using a deformed tube is reduced. The drawbacks are low and short service life.

Therefore, a deformed tube that can be manufactured in a short time at low cost, has no play in fitting the male shaft to the female shaft, operates without galling or seizure, and has a long service life has been desired.

(Means for Solving the Problems) In order to solve this problem, the method for manufacturing a modified tube according to the present invention is characterized in that in manufacturing a modified tube in which a male tube is fitted in a female tube so as to be slidable in the axial direction, drawing is performed. The opening shape at the outlet end corresponds to the female tube,
A die in which the shape of the opening at the end of the withdrawal inlet is a circular opening having a diameter corresponding to the size of the small-diameter portion with an irregular shape, and the cross-section of the opening continuously increases from the inlet to the outlet and changes from circular to irregular. , The outer contour of the withdrawal outlet end corresponds to the male tube, the outer contour of the withdrawal inlet end is a circular contour having a diameter corresponding to the dimension of the irregularly shaped small diameter portion, and a cross section of the outer contour from the inlet to the outlet. Using a mandrel that continuously expands and changes from a circular shape to a deformed shape, fits the mandrel in the die, and allows the clearance between the die and the mandrel to enter each other from the inlet end. The two fitted metal tubes are introduced and simultaneously pulled out from the outlet end.

In practicing the present invention, it is preferable to subject the inner and outer surfaces of the metal tube to a caustic treatment.

(Operation) By simultaneously extracting two metal tubes fitted to each other, a deformed tube having no play can be manufactured in a short time. If two metal pipes were machined or broached separately, it would take time to adjust after processing, and play could not be completely removed. A modified tube can be manufactured.

(Example) As an example of a deformed tube, a part is shown in a perspective view in FIG. 1, and an end face is shown in FIG.

The deformed tube of this embodiment comprises a male tube 2 and a female tube 4 which are star-shaped tubes manufactured from carbon steel tubes for machine structures. The carbon steel pipe may be a seamless steel pipe having a circular cross section or a seamless steel pipe. Although the illustrated irregular-shaped tube has a star shape, it may be a triangular or square irregular-shaped tube.

In manufacturing the modified tube, a die 6 and a mandrel 8 are used in the present invention as shown in FIG.
First, a caustic treatment such as a phosphate coating treatment is applied to the inner and outer surfaces of the steel tube to be the male tube 2 and the steel tube to be the female tube 4. Alternatively, molybdenum disulfide or tungsten disulfide may be coated. This process may be omitted on the inner surface of the male tube.

FIG. 3 shows the opening shape and the outer contour shape of the exit end of the drawing of the combination of the die 6 and the mandrel 8, and the cross-sectional shapes of the male tube 2 and the female tube 4.

The opening shape of the drawing outlet end of the die 6 corresponds to the cross-sectional shape of the female tube 4, and the opening shape of the drawing inlet end of the die 6 has the size of the irregular small diameter portion as shown by a dotted line 12 in FIG. A circular opening having a corresponding diameter, and the cross section of the opening continuously increases from the inlet to the outlet, and changes from a circular shape to an irregular shape.

The outer contour of the withdrawal outlet end of the mandrel 8 corresponds to the cross-sectional shape of the male tube 2, and the outer contour of the withdrawal inlet end of the mandrel 8 has a modified small diameter portion as shown by a dotted line 10 in FIG. It is a circular contour having a diameter corresponding to the dimension, and the cross section of the outer contour continuously increases from the inlet to the outlet, and changes from a circle to an irregular shape.

As described above, the clearance between the die 6 and the mandrel 8 fitted in the die 6 whose cross-sectional shape is similar to each other from the inlet to the outlet and which continuously expands and changes into an irregular shape is formed. Then, two cylindrical metal tubes fitted to each other are introduced. The inner and outer diameters of the fitted cylindrical metal tubes at the time of introduction correspond to those indicated by dotted lines 10 and 12 in FIG.

The two cylindrical metal pipes introduced from the inlet end into the clearance of the combined body of the die 6 and the mandrel 8 are gradually expanded until reaching the outlet end, and the solid line in FIG. At the outlet end, it is withdrawn as a profiled tube as indicated by. This drawing may be so-called cold drawing at room temperature, or may be warm drawing at 200 ° C. to 500 ° C. in some cases.

In this embodiment, the case of a steel pipe has been described, but other metal pipes such as a steel pipe and an aluminum pipe may be used.

As described above, the deformed tube can be easily manufactured by simultaneously extracting the tube 2 and the female tube 4 using the die 6 and the mandrel 8.

(Effects) As is clear from the above description, according to the present invention, the male tube 2 and the female tube 4 fitted to each other are pulled out with respect to the die 6 and the mandrel 8, so that play is reduced. Therefore, there is an effect that a deformed tube having a long service life which does not generate noise by sliding smoothly in the axial direction during power transmission can be simply and inexpensively manufactured.

[Brief description of the drawings]

1 is a perspective view of a modified tube manufactured by the method of the present invention, FIG. 2 is an end view of the modified tube of FIG. 1, and FIG. 3 is an end view showing the modified tube together with a die and a mandrel at the time of manufacture. . 2 ... male tube, 4 ... male tube 6 ... die, 8 ... mandrel 10,12 ... taper end of metal tube before drawing

Claims (2)

(57) [Claims] When manufacturing a deformed tube in which a male tube is fitted in a female tube so as to be slidable in the axial direction, the shape of an opening at a drawing outlet end corresponds to the female tube, and a drawing inlet end. Is a circular opening having a diameter corresponding to the size of the small-diameter portion having a deformed shape, a cross-section of the opening continuously expanding from the inlet to the outlet, and changing from a circular shape to a deformed shape. The outer contour of the portion corresponds to the male tube, the outer contour of the drawn inlet end is a circular contour having a diameter corresponding to the size of the irregularly shaped small diameter portion, and the cross section of the outer contour continuously extends from the inlet to the outlet. Using a mandrel that expands and changes from a circular shape to a deformed shape, the mandrel is fitted into the die, and the clearance between the die and the mandrel is fitted to each other from the inlet end. Piece of gold Introducing tube, a manufacturing method of the profile tube, characterized in that pulling simultaneously from the outlet end. 2. The method according to claim 1, wherein a coating treatment is performed before drawing the two metal tubes.