JPH055568B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention manufactures a rough shaped material for a rear axle tube that is fixed to both ends in the vehicle width direction of a rear axle housing of an automobile and rotatably supports a rear wheel hub. It is about the method.

(Prior Art) First, the structure of a rear axle tube whose rough profile is manufactured by the method of the present invention will be explained with reference to FIG. Reference numeral 10 in the figure is a rear axle tube fixed by welding 14 to the outer end of the vehicle body of a rear axle housing 12, only a portion of which is shown by a dashed line. Rear axle tube 1
0 consists of an enlarged diameter part 16 inside the vehicle body, that is, on the side of the rear axle tube 12, and a small diameter part 18 outside the vehicle body, and a hollow hole 20 is provided along the central axis thereof. A rear axle shaft 22 whose inner end (not shown) is connected to a differential is loosely fitted into the hollow hole 20, and a bolt 26 is attached to a flange portion 24 formed at the outer end of the vehicle body of the shaft 22.
A rear wheel hub 28 is fixedly secured thereto. The rear wheel hub 28 is rotatably supported on the outer peripheral surface of the rear axle tube 10 by an inner bearing 30 and an outer bearing 32, and an oil seal 36 is provided at the open end inside the vehicle body via a ring-shaped oil seal retainer 34. is installed to prevent the grease sealed inside from leaking. Further, a flange 38 is provided protruding from the outer periphery of the rear wheel hub 28, and a rear brake drum 42 is mounted on the flange via hub bolts 40.

The rear axle tube 10 has an outer circumferential surface a into which the inner bearing 30 is fitted, an outer circumferential surface b into which the outer bearing 32 is fitted, a threaded portion c into which the lock nuts 44 and 46 that fix the outer bearing 32 are screwed together, and an oil Seal retainer 34
Since machining is performed on the outer circumferential surface d, etc. where the parts are fitted, the rough shape material before machining must have a shape that includes the necessary cutting allowance for these parts to be machined. Conventionally, the above-mentioned rough shapes have been manufactured by upset processing. Now, a typical manufacturing method for a conventional rear axle tube rough section will be explained with reference to FIG. 4. First, as shown in FIG. 4, a solid round bar 48 of a predetermined length is prepared as a raw material. Ru. Since the solid round bar 48 is gripped by a grip die of an upsetter (not shown), it has a grip allowance 50 shown with diagonal lines in the figure, and this grip allowance remains until it is punched out in the final process. After the end of the round bar material 48 opposite to the grip width 50 is heated by high-frequency induction heating or other heating means, the round bar material 48 is mounted on an upsetter,
In the second step shown in FIG. 2, a large diameter portion 52 is formed at the heating end, and in the next third step, as shown in FIG. A hole 54 is formed, and in the final step shown in FIG. At this time, the grip section 50 is separated from the rough section. In the conventional upset processing method described above, the grip distance is at least 5
Since unnecessary material is required by the amount of 0, the material yield is poor and manufacturing costs inevitably increase.

(Problems to be Solved by the Invention) The present invention improves the shortcomings of the above-mentioned upset processing method, which has been widely used in the past when manufacturing rear axle tube rough shapes, that is, the material yield is low.
The purpose is to provide a manufacturing method with excellent material yield.

(Means for Solving the Problems) The present invention was devised to achieve the above-mentioned object, and the present invention heats the end of a pipe material that has been cut to a required size in advance and then inserts it into a molding die. The tube expansion part that is press-fitted into the hollow hole of the pipe material to expand its inner and outer diameters contacts the end of the pipe material and presses it in the axial direction. A punch having a shoulder for upsetting is press-fitted to perform upsetting and pipe expansion at the same time, thereby expanding the diameter of the end of the pipe material and forming an enlarged diameter portion with increased thickness. The gist of this paper is a method for manufacturing a rear axle tube rough section.

(Function) According to the present invention, unlike the conventional upset method, a pipe material cut to an appropriate size is used as a material, and the end thereof is heated and placed in a molding die.
By press-fitting a punch that performs upsetting and expansion at the same time into the heated end of the pipe, an enlarged diameter section having the desired shape is formed, so the gripping allowance required in the upsetting method is completely unnecessary. First, a material yield of substantially 100% or close to 100% can be obtained, and the manufacturing cost of the rear axle tube can be correspondingly reduced.

(Example) Examples of the method of the present invention will be specifically described below with reference to FIGS. 2 and 3. (Members and parts that are substantially the same as the rear axle tube and its constituent parts already explained with reference to FIG.
As a material for the rear axle tube 10, a pipe material 56, a part of which is indicated by a dashed line in FIG. Heat the end portion shown in 400℃ to 400℃ using high-frequency induction heating or an appropriate heating furnace.
It is heated to a temperature of about 1000° C., preferably about 800° C., and then charged into the die 58 for the first process shown in FIG. The die 58 is fixed on the bed or bolster of a screw press or any other press device by a well-known tightening means, while the punch 60 for the first step is attached to a head or ram (not shown), and the die 58 is fixed as shown by arrow P in the figure. It is press fit into the heated end of the pipe material 56. The punch 60 is a pipe material 56
In order to enter into the hollow hole and press the pipe material 56 in the axial direction by coming into contact with the papilla-shaped or conical pipe expanding part 60a which enlarges the inner diameter and therefore the outer diameter, and the pipe end part, to plastically deform it, that is, to stagnate it. The die 58 has a shoulder portion 60b of the punch 60, and the die 58 has an expanded tube portion 60a of the punch 60.
A papillary or conical recess 58a with a shape corresponding to
is provided. Due to the cooperation of the die 58 and the punch 60, a papillary or conical enlarged diameter portion 56a is formed at the heated end of the pipe material 56 in the first step.

The pipe material 56 that has been processed in the first step is
It is transferred to the second step shown in the figure. The die 62 in the second step has a recess 62a near its upper end that defines the shape of the enlarged diameter part of the rough profile, and the recess 62a is later machined to form the oil seal retainer 3.
4 and the inner bearing 3 adjacent to the same retainer.
It includes molding step portions 64 corresponding to the step portions of the rough-shaped material serving as the outer circumferential surfaces b and d on which the 0 is mounted. On the other hand, a punch 66 for the second process cooperates with the die 62.
is a papillary or conical enlarged tube portion 66a that defines the inner peripheral surface shape of the hollow hole in the enlarged diameter portion of the rough shaped material;
It includes a shoulder portion 66b that comes into contact with the pipe end portion and presses and upsets the pipe material 56 in the axial direction. Similarly to the first step, by displacing the punch 66 in the direction of arrow P with respect to the die 62 and simultaneously expanding and upsetting the heated end of the pipe material 56,
Finally, the rough profile of the rear axle tube is formed.

According to the above method, it is possible to manufacture a rough shape material for a rear axle tube from a pipe material as a raw material with a yield of substantially 100%, and there is an advantage that the manufacturing cost can be reduced. In the above example, the rough shape material of the rear axle tube is expanded and swaged in two steps. However, depending on various conditions such as the size and shape of the rear axle tube and the capacity of the forming press, Items with a simple external shape may be molded in one step; conversely, if a large item with a complex external shape is to be molded using a press with a relatively small capacity, three or more steps may be required. Sometimes it is necessary.

(Effects of the Invention) As described above, the method for producing a roughly shaped rear axle tube according to the present invention involves heating the end of a pipe material cut to a required size in advance and charging it into a molding die. Into the heated end of the pipe material, an expanding part is press-fitted into the hollow hole of the pipe material to enlarge its inner and outer diameters, and a pipe expansion part that comes into contact with the end of the pipe material and presses it in the axial direction is installed. A punch having a shoulder for inserting is press-fitted to perform upsetting and pipe expansion at the same time, thereby expanding the diameter of the end of the pipe material and forming an enlarged diameter portion with increased thickness,
Compared to the conventional upset method, the material yield can be significantly improved, and manufacturing costs can be reduced accordingly.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of a rear axle tube whose rough profile is manufactured by the method of the present invention and rear axle constituent members that cooperate with the tube, and FIG.
The figure is a conceptual cross-sectional view showing the first step of the method of the present invention,
FIG. 3 is a conceptual sectional view showing the second step of the method of the present invention, and FIGS. 4A to 4D are drawings showing the steps of manufacturing a rear axle tube rough section by the conventional upset method. 10... Rear axle tube, 12... Rear axle housing, 16... Expanded diameter section, 18...
Small diameter portion, 20...Hollow hole, 22...Rear axle shaft, 28...Rear wheel hub, 58 and 62...Die, 60 and 66...Punch.

Claims (1)

[Claims] 1 The end of a pipe material cut to the required size in advance is heated and charged into a molding die, and the heated end of the pipe material is press-fitted into the hollow hole of the same pipe material. Upsetting and expanding the pipe are performed simultaneously by press-fitting a punch having an expanding part for enlarging the inner and outer diameters and a shoulder part for abutting against the end of the pipe material and pressing it in the axial direction for upsetting. A method for producing a roughly shaped rear axle tube, comprising expanding the diameter of the end of the material and forming an enlarged diameter portion with increased thickness.