JPS5838256B2 - Manufacturing method for automotive axle housings - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing an axle housing for an automobile by using a tubular material and subjecting the tubular material to drawing and hydraulic bulging.

Conventionally, axle housings for automobiles have been manufactured by welding together several parts obtained mainly by pressing plate materials.

That is, as illustrated in FIG. 1, the main components are sheet metal housings 1 and 2 divided at the center, end tubes 3 and 4, and a differential gear housing dome 5, and a differential mounted in the housing. A reinforcing plate (not shown) attached to the gear insertion port is added thereto, and these are joined by welding.

In addition, the end tubes 3 and 4 are divided into two in the axial direction,
There is also a method of manufacturing them as one unit with each of the two divided sheet metal housings 1 and 2, but in any case, since the individual parts are manufactured from sheet metal, the process from sheet metal pressing to sheet metal pressing is possible. Not only does it require many processes, including shaping, trimming, adjusting the joints between parts, joining, and inspecting the joints, but there are large variations in shape and dimensions due to welding, and it is difficult to correct the shape. A distortion removal step is also required.

Therefore, many steps are required to manufacture the gear, and a step is also required to check for leakage of the lubricating oil for the internally housed gear due to defects in the contact points.

The present invention provides a method for manufacturing automotive axle housings that significantly reduces the number of steps compared to such conventional methods, reduces the weight of the product, and is of high quality and easy to mass produce. This is what we provide.

Hereinafter, the method of the present invention will be explained in detail with reference to the drawings.

The method of manufacturing an automobile axle housing according to the present invention includes a drawing process in which the diameters of both ends of a material tube are reduced to shape the end tube portion, and a differential gear is formed by bulging the center portion of the material tube. The process consists of a hydraulic bulge processing step in which the dome portion to be accommodated is formed, and a post-processing step in which an insertion port for the drive mechanism is provided in the pre-shaped tube obtained by both of the above steps, and a reinforcing plate is bonded around the insertion port. It is something.

FIG. 2 shows a material tube 10 for manufacturing an axle housing by such a process. This material tube 10 is made of a low carbon steel pipe or the like, and its cross-sectional shape does not necessarily have to be circular. It is also possible to use a tube with a polygonal cross-section, including corners.

The above-mentioned drawing process is a process of reducing the diameter of both ends of the material tube 10. In this drawing process, the outer surface of the central part of the material tube 10 is held by a holding die, and a drawing hole of a predetermined diameter is formed into a tapered shape. A drawing die with a drawing part of
By pushing the tube from both ends toward the center, both ends of the material tube are drawn, resulting in a drawn tube 1 as shown in Figure 3.
Get 1.

In this drawing process, even if the material tube 10 has a circular cross section, it can be drawn into a polygonal shape.

The diameter reduction rate obtained by one drawing process is about 10 to 15% in this type of drawing process, and if the drawing process exceeds this, the center of the material tube may be deformed or the drawn part may be damaged. Buckling occurs.

Therefore, drawing is performed multiple times using a drawing die with sequentially smaller drawing holes to obtain a drawn tube of the desired shape.

In the hydraulic bulge process, bulge hydraulic pressure is applied to the inside of the drawn pipe 11 in the expansion mold, and
The bulging mold is compressed in the axial direction, and the central portion 12 of the drawn tube 11 is bulged.

As a result, the central portion of the drawn tube 11 is bulged in a cold state following the shape of the cavity of the bulge mold, thereby obtaining the bulged tube 13 shown in FIGS. 4 and 5.

The diameter increase rate obtained by one bulge or shape is about 50% for this type of shape, and if processing exceeding this is performed, an intermediate bulge or shape step is provided, and intermediate annealing is performed. Perform multiple expansions with the help of

What is particularly important in this hydraulic bulging process is that the differential gear housing dome 14 is located in the central portion 12 of the drawn tube 11.
and the excess meat absorbing domes 15 are provided symmetrically.

If only one portion of the central portion 12 of the drawn tube 11 is bulged to form the differential gear housing dome 14, buckling or rupture may occur during forming and forming, and the desired forming may not be possible. Even if it could be made to look great, many wrinkles would occur, but as in the present invention, the differential gear housing dome 14
Such a problem can be solved by providing the excess flesh absorbing dome 15 in a symmetrical position to substantially equalize the amount of bulge per unit of the aperture tube 11. can.

There is no problem in performing either of the above-mentioned drawing process and hydraulic bulging process first, but if each of the two processes involves multiple rounds of forming, both forming processes should be performed in parallel. However, in this case, consideration should be given to performing intermediate annealing for both moldings at the same time.

In the thus obtained shaped tube (bulging tube 13), as a post-processing step, the excess thickness absorbing dome 15 is removed leaving seven flange portions 16 around it, and an insertion opening for inserting the drive mechanism is formed. A reinforcing plate 19, which serves as a mounting portion for the drive shaft, is joined to the flange portion 16 around the insertion port 18 by welding or the like.
A basic structure 17 of an automobile axle housing shown in FIG. 6 is obtained.

In the axle housing that is put to practical use, auxiliary parts are joined to the basic structure 17.

7 and 8 schematically show the state in which the axle housing is installed on an automobile.
0b is a suspension mechanism mounting bracket, 21a and 21b are brake mounting brackets, 22a z 22b are tires, 23 is a drive shaft, 24 is a universal joint, and F indicates the vehicle body load applied via a spring. There is.

As described above, according to the method of the present invention, a certain shape of the axle housing without joints can be formed by subjecting the material tube to drawing and hydraulic bulge processing, compared to conventional methods. As a result, the number of process steps is significantly reduced, mass production can be easily carried out, and lightweight, high-quality products can be obtained.

In particular, in the hydraulic bulging process, it is effective to form the excess thickness absorbing dome at a position symmetrical to the differential gear housing dome in order to obtain the high quality product.

Furthermore, in general, when an axle housing is equipped on an automobile, an even bending moment acts on it in the axial direction, but the axle housing manufactured by the present invention has a thicker wall thickness at the narrow diameter portion. In this case, the wall thickness of the large diameter portion becomes thinner, and the strength against bending moment becomes substantially constant, so that it is possible to obtain an axle housing that is efficient in terms of strength.

Note that, as described above, if the drawn portion of the material tube is shaped into a polygonal shape, the suspension mechanism mounting bracket can be joined to the flat portion, so that joining can be easily performed.

Next, a processing device that performs the above-mentioned processing will be explained.

Figure 9 shows the configuration of a device for drawing both ends of the material tube 10, the upper half of which shows the state before drawing, and the lower half of which shows the state after drawing. In the apparatus, the outer surface of the central part of the material tube 10 is firmly held between holding molds 30 and 31 divided into upper and lower parts, and the material tube 1 is
Drawing dies 32ay32b located outside both ends of 0
The piston 3 of the hydraulic press 3 3 a, 3 3 b
4 a t 3 4 b pressurizes toward the center of the material tube and pressurizes the die 32 a p 32 b with tapered constricted portions 35 a, 35 b and constricted holes 3 6 a, 3 6
b. The diameters of both ends of the raw material tube 10 are reduced to obtain a drawn tube 11.

In addition, in the figure, 3 7 a and 3 7 b indicate guides for guiding the drawing die.

The holding molds 30 and 31 are used to suppress the movement of the material tube to the left and right during the drawing process and when the die retreats after the completion of the process. During the process, a hydraulic press (not shown) applies a load to the holding mold 30. Apply F2.

The portion of the material tube held by the holding dies 30, 31 corresponds to the portion that will be bulged by the hydraulic bulge process, and if that portion is deformed during the drawing process, the bulge shape will be inhibited.

In order to avoid this deformation, as described above, the diameter reduction rate is set to about 10 to 15%, and drawing is performed multiple times using a plurality of drawing dies having drawing holes of corresponding diameters.

FIG. 10 shows the structure of a hydraulic bulge processing device that performs a bulging process on the drawn pipe 11 obtained by the drawing process, the upper half of which shows the state before the bulging process, and the lower half of which shows the state before the bulging process. Shows the state after processing.

In this hydraulic bulge processing device, the left and right bulging molds 40a and 40b are divided into vertically divided molds 41a and 42a and 4lb and 42b on the axial plane to facilitate attachment and detachment of the processed tube. These bulging molds have a pair of mold cavities 4 for forming a hollow portion corresponding to the shape of the axle housing when they are joined together.
3a, 44a, and 43b, 44b are recessed.

These left and right bulging molds 40a and 40b are held slidably left and right between the upper and lower guide molds 45 and 46, and when bulging or shaping the drawn pipe 11, as shown in the upper half of Fig. 10. It is accommodated in a bulging mold 40a t 40b arranged with a gap 47 in the center.

In order to prevent the upper split mold 41at4lb from floating due to the bulge hydraulic pressure generated during expansion or molding,
A load F3 is applied by a ram 48 of a mold clamping press via a guide mold 45. When installing or removing a processed pipe, the ram 48 applies a load F3 to the upper split mold 4.
1at4lb is raised.

When applying the bulge hydraulic pressure P to the drawn pipe 11, in order to seal the bulge liquid pressure introduced into the pipe at both end faces of the drawn pipe 110, first, press the cylinders 4 9 a t 4 9 b of the compression press. The hydraulic pressure pa is applied to move the sealing rod 50at50b toward the center.

As a result, the tip of the rod 50a t sob comes into contact with the end surface of the drawn tube 11, making it possible to seal it.

Also, at this time, the bulging mold 40a t 40b advances toward the center via the connectors 51a and 51b, and a part of the mold cavity comes into close contact with the tapered portion of the drawn pipe 11.

The above hydraulic pressure Pa1 is the bulge hydraulic pressure P in the drawn pipe 11.
This is much smaller than the hydraulic pressure Pa required to compress the pipe after it has been introduced.

Next, oil is supplied from the bulge hydraulic pressure introduction hole 52, and the air discharge hole 5
After opening the stop valve 54 of No. 3 to release the air inside the drawing pipe 11, the stop valve 54 is closed to allow the bulge hydraulic pressure P to act inside the drawing pipe 11. 49b, the expansion molds 40a, 40b and the sealing rods 50a, 50b are advanced toward the center, compressing the drawn pipe 11 from both sides.

During this compression process, the bulge hydraulic pressure P acting within the drawn tube 11 is increased to bulge or shape the central portion of the drawn tube 11 into a desired cavity shape, and the bulged tube 13 is expanded. get.

After the molding is completed, the pistons 55a and 55b of the compression press
At the same time, the split molds 41a and 41b are raised by the ram 48 of the mold clamping press, and the bulging pipe 13 is taken out.

In addition, numeral 56 in the figure is a table of the forming machine to which the guide mold 46 and the cylinder 49at49b of the compression press are fixed.

FIG. 11 is a central cross-sectional view to clearly show the shape of the bulge formed by the above-mentioned hydraulic pulge processing device.The largest bulge is formed at this central position, and this position is the center. As a result, a housing dome 14 for a differential gear, which has conventionally been difficult to integrally mold, is used.

The excess thickness absorbing dome 15 located symmetrically to the differential gear housing dome 14 is used to form an insertion opening 18 (FIG. 6) for the drive mechanism by cutting it after molding.
Seven flange portions 16 for attaching reinforcing plates 19 are formed around the excess thickness absorbing dome 15.

As mentioned above, the extra-thickness absorbing dome 15 plays an important role in hydraulic bulge processing, whereby the amount of bulge around the center axis of the drawn pipe 11 is approximately equalized, and the bulge or This can prevent buckling or rupture during shaping.

In addition, in the figure, 57 is a knockout rod for pressing the surplus thickness absorbing dome 15 and pressing the bulging pipe 13 after a certain shape.
Reference numeral 8 denotes an oil groove for discharging oil present in the mold cavity or mutual gap of the bulge-shaped mold to the outside during the bulging process, and 59 and 60 denote a mold 45 that guides the divided molds 41a, 41b, 42a>42b.
, 46.

In such a bulge, if the diameter increase rate exceeds 50%, it is necessary to provide an intermediate bulge shaping process as described above.

In the hydraulic bulge processing apparatus described above, this intermediate bulging can be performed by using an auxiliary mold for intermediate forming, and FIG. 12 shows this mode.

In the figure, the upper half shows the state before the bulging process, and the lower half shows the state after the bulging process.

The intermediate auxiliary molds 61 and 62 used in this intermediate bulge forming process are placed at the center of the gap 47 between the left and right bulge molds 40a and 40b in the hydraulic bulge processing device. Then, the pipe is divided into upper and lower parts, and at the time of the next bulge, the amount of compression that matches the amount of bulge is applied to the intermediate bulge pipe 13.
′, have a thickness corresponding to the amount of compression,
In addition, mold cavities 63 and 64 are provided so that the rate of increase in diameter of the bulging portion of the drawn tube 11 can be controlled to about 50%.

The order of the intermediate bulges is the same as that described with reference to FIG.

The shape of the processed tube 13' when the intermediate bulging or shaping is completed leaves a void 65 in the mold cavity of the bulging mold 40ay 40b, but the void 65 disappears by the next bulging or shaping.
It is possible to form an axle housing with a diameter increase of greater than 50%.

Incidentally, the intermediate bulging pipe 13' is subjected to intermediate annealing prior to the subsequent bulging shaping.

Next, examples of the present invention will be shown.

The material pipe has an outer diameter of 40mm, a wall thickness of 2mm, and a total length of 3807mm.
Using a W7M seamless low carbon steel pipe, as a first step, the diameters of both ends of the material pipe were reduced using a drawing device as shown in FIG.

Since the diameter reduction rate that can be performed in one drawing process is about 10 to 15%, the drawing process was performed four times.

The processing conditions are shown in Table 1. As the second stage hydraulic bulging process, an intermediate bulge forming process was provided because the diameter increase rate of the innermost bulging part of the bulging pipe exceeded 50%.

The dimensions of the mold cavity of the intermediate molding auxiliary mold used in this step were 56 mm in diameter and 12 mm in thickness so that the diameter increase rate of the intermediate bulging tube relative to the material tube was about 50%.

The bulge hydraulic pressure required for this form is 300 k at the start.
g/Cd was approximately 400 kg/crri at the end of the course.

Next, the intermediate bulge tube was subjected to intermediate annealing at 700°C, and then bulged into the shape required for the axle housing using a hydraulic bulge machine as shown in FIG.

The bulge hydraulic pressure was 200 kg/cd at the start and 1500 kg/cnf9 degrees at the end.

The final dimensions of the bulge are R and R in Figure 11.
2 are 76 ho and 72 guan respectively.

In the third step, the excess thickness absorption dome of the pre-shaped tube obtained by the above processing was removed, an insertion opening for the drive mechanism was provided, and a reinforcing plate 19 was joined around the insertion opening to obtain an axle housing.

[Brief explanation of drawings]

Fig. 1 is an exploded view showing a configuration example of a conventional automobile axle nozzle, Fig. 2 is a front view of a raw pipe processed by the present invention, Fig. 3 is a front view of a drawn pipe, and Fig. 4 5 is a front view and a plan view of a bulging pipe, FIG. 6 is a sectional view of an axle housing manufactured according to the present invention, and FIGS. 7 and 8 are views of an axle housing installed in an automobile. A front view and a plan view, FIG. 9 is a longitudinal sectional view of the drawing device, and FIG. 10 is a longitudinal sectional view of the hydraulic bulge processing device.
Figure 1 is an enlarged cross-sectional view taken along line A-A in Figure 10.
FIG. 2 is a sectional view of a main part showing a state in which an auxiliary mold for intermediate bulging is used in a hydraulic bulge processing device. 10...Material pipe, 11...Drawn pipe, 13...
Bulging pipe, 14...Differential gear housing dome, 15...
・Excess meat absorption dome, 18...Insertion port, 19...Auxiliary plate, 30, 31...Retention type, 3 2 a t 3 2
b... Drawing die, 3 5 a y 3 5 b.
...Tapered aperture part, 36at36b...Aperture hole, 4
0ay40b...Bulge mold, 43a, 43b t
44a t 44b・-type fossa.

Claims (1)

[Claims] 1. The diameter of both ends of the material tube is reduced by holding the outer surface of the central part of the material tube with a holding mold and pushing a drawing die having a tapered drawing part and a drawing hole from both ends of the material tube. Drawing process: A bulge hydraulic pressure is applied to the inside of the drawn tube in the divided bulge mold, and the bulge-shaped mold is compressed in the axial direction, causing a bulge or A hydraulic bulging process in which a bulging tube symmetrically provided with a differential gear housing dome and an excess thickness absorbing dome is bulged or shaped according to the shape of the cavity in the mold; A post-processing step in which an insertion port for a drive mechanism is formed by cutting off an excess thickness absorption dome placed on a certain shaped pipe, and a reinforcing plate is bonded around the insertion port. Production method.