JPH10329503A - Manufacture of axle case and axle case - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the manufacturing method of an axle case which can manufacture the axle case with a high dimensional accuracy without the direction of the yield of a material, and the axle case. SOLUTION: By restriking the half cut end part 6 of the form part 5 while holding the form part 5 with a shape nearly half cut an axle case 3 between upper die 20 and a lower die 15, the shape of the form part 5 is matched with the upper/lower dies 15, 20 and deformed and also the half cut end part 6 is arranged straightly and the restrike part 9 is welded with two half cut end parts 6 mutually. As the half cut end part 6 is restriked and arranged straightly, the yield of a material is increased without the generation of a wastefull welding cut part entirely. At the same time, as the shape of the form part 5 is matched with the upper/lower dies 15, 20 and deformed by this restrike, the axle case 3 with a high size accuracy can be manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an axle case manufacturing method and an axle case.

[0002]

2. Description of the Related Art In a two-axle vehicle such as a truck or a bus, a normal axle case containing a differential gear is used for a front drive axle, and a dead axle case is used for a rear driven axle. . Such a dead axle case (hereinafter simply referred to as an axle case) is shown in FIG.
As shown in the figure, the center has a square cross section 1 for increasing rigidity, and both ends have a round cross section 2 for welding an end tube. A typical method of manufacturing the axle case 3 will be described with reference to FIG.

[0003] First, as shown in Fig. 1 (a), a blank 4 made of a rectangular plate is pressed to form a foam product 5 having an axle case 3 approximately half as shown in Fig. 1 (b). Molding. Next, the half-end 6 of the foam product 5 is trimmed by gas cutting to form a straight shape 7 as shown in FIG. 1 (c) and to form a groove 8 for welding. Then, as shown in FIG. 1D, two trim products 9 are butt-welded and welded to manufacture the axle case 3.

[0004]

In the axle case 3, the outer dimensions of the angular section 1 and the round section 2 are determined in view of the layout of the vehicle. The point of design is how to secure the fatigue strength. The bending stiffness is determined by the thickness t1 and R1 of the square section 1 shown in FIG. 2, and the neck portion of the fatigue strength is the welded section 10 between the round section 2 and the end tube.
The strength is determined by the thickness t2 of the round section 2. Therefore, from the viewpoint of bending stiffness and fatigue strength, it is desirable that R1 of the angular section 1 be as small as possible and that the plate thickness t2 of the round section 2 be greater than t1.

However, in the axle case manufactured by the conventional method, since the rectangular plate-shaped raw material 4 is formed by pressing, the plate thicknesses t1 and t2 of the square section 1 and the round section 2 are naturally determined. Are the same, and the plate thickness t2 of the round section 2
Only can not be thick. In addition, the R
If the size of No. 1 is too small, problems such as cracking and thinning occur during press working, and there is a limit to reducing R1.

Further, as shown in FIG. 2, since the circumferential length L2 of the round cross section 2 is shorter than the circumferential length L1 of the square cross section 1, the conventional method of pressing a rectangular plate-shaped material 4 has a round shape. The trimming of the halved end 6 of the section 2 is required, while
Since it is impossible to ensure the accuracy required for welding even at the square cross-section 1 only by press forming, it is necessary to provide a trim allowance at the half-end portion 6, and as a result, the material yield must be deteriorated. Did not.

Further, since the trim is performed by gas cutting, thermal distortion is apt to occur, and thermal deformation occurs after cutting. Therefore, it is necessary to set a trim line in consideration of this thermal deformation, but this is extremely difficult and causes a defective product. In addition, when the gas is cut, slag (fused chips) is generated at the cut portion, and the slag adheres to the cut portion, so that a slag removing step is required.

Further, since the trimming process by gas cutting is a heating operation, it must be performed in a place different from a press factory.
There were various problems, such as inventory management of pre-trim products, transportation, securing a work place, obligatory use of shading glasses and shading plates as safety measures against gas emission, and gas management.

Further, since the rectangular plate-shaped material 4 is formed by press working, as shown in FIG. 2, the cross-sectional central portions 11 and 12 which are the maximum stress generating portions are also the cross-sectional central portions which are the minimum stress generating portions. Since both end portions 13 and 14 were also formed with the same thickness, the thickness distribution was inappropriate as a strength member.

An object of the present invention, which has been made in view of the above circumstances, is to provide an axle case manufacturing method and an axle case that can manufacture an axle case with high dimensional accuracy without deteriorating the material yield. .

[0011]

In order to achieve the above object, a method of manufacturing an axle case according to the present invention is to provide a method for manufacturing an axle case in which an axle case is formed by halving a foam product between an upper mold and a lower mold. By restriking the halved end of the foam product, the shape of the foam product is deformed according to the upper and lower molds, and the halved ends are straightened. It is intended to be welded by.

According to the present invention, the half-end portion of the foam product is straightened by restriking instead of the conventional trimming by gas cutting, so that no useless welded cut portion is produced and the material is cut. The yield is improved and thermal deformation due to gas cutting does not occur. Also, at the same time, the shape of the foam product is deformed according to the upper and lower molds by this resilience, so that an axle case with high dimensional accuracy can be manufactured.

Further, the above foam article is formed into a square cross section at the center and both ends are formed into a round cross section. The thickness of the cross section may be increased, and a welding groove may be formed at the half-split end to obtain a restri-like product. Thereby, the bending rigidity and the fatigue strength are improved, and the trouble of forming the welding groove can be omitted. Conversely, if the same bending stiffness and fatigue strength as in the prior art are sufficient, the plate thickness can be reduced, which leads to a reduction in weight.

[0014] Further, the foamed article is molded so as to have an uneven portion in the center of the cross section, and the restrike is
By forming the concave and convex portions in addition to the above-mentioned half-split end portions, the plate thickness at the center of the cross section of the restrike product may be made thicker than other portions. Thereby, the thickness of the maximum stress generating portion is increased, and the rigidity is improved.

That is, in this axle case, an axle case main body is formed from a central angular cross-section and a round cross-section at both ends thereof, and the upper and lower portions of the axle case main body extend along the longitudinal direction of the case main body. It is formed by forming a thick part.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the accompanying drawings.

First, as shown in FIG. 1A, a raw material 4 made of a rectangular plate having a uniform thickness (10 mm or more) is prepared.
Next, the material 4 is pressed by a known press working as shown in FIG.
As shown in (b), the axle case 3 is formed into a foam product 5 having a substantially half-shape. This foam product 5
The center in the longitudinal direction is formed into a square cross section 1, and both ends are formed into a round cross section 2.

Here, as shown in FIG. 2, since the circumferential length L2 of the round section 2 is shorter than the circumferential length L1 of the angular section 1, the surplus portion Is molded. In addition, the half-end portion 6 of the corner section 1 also
In order to secure the required accuracy at the time of 100% butt welding (see FIG. 1 (d)), a predetermined surplus portion for restriking is formed in advance.

Next, such a foam product 5 is inserted into the concave portions 16 and 17 of the lower die block 15 as shown in FIGS.
Housed in The recesses 16 and 17 are formed in accordance with the external shape of the restriking product 9 shown in FIG. 1C, which is an accurate half-shape of the axle case 3 (finished product). 4 and a tapered recess (not shown) formed between the square recess 16 and the round recess 17. The rectangular recess 16 is provided with a pad 18 and a cushion pin 19 for ejecting the work after restriking.

An upper die punch 20 is inserted into the recesses 16 and 17 at a predetermined pressure. The upper die punch 20 is integrally formed so as to have a width that engages with the square concave portion 16, the round concave portion 17, and the tapered concave portion of the lower die block 15, and a wide portion 21 that freely moves up and down; The square convex portion 25, the round convex portion 26, and the tapered convex portion formed on the lower surface of the portion 21 and formed in accordance with the angular cross section 22, the round cross section 23, and the tapered cross section 24 of the restlike product 9 (FIG. (Not shown), pressing portions 27 formed on the left and right edges of the lower surface of the wide portion 21, and a triangular cross-section for forming the welding groove 8 on the resiliency product 9 formed on the pressing portion 27. And a groove portion 28.

The upper die 20 is connected to the lower die block 1
5, the foam product 5 is restrained in the upper and lower dies 20 and 15, and the half-split end portion 6 of the foam product 5 is restricated by the pressing portion 27. Thereby, the left and right half ends 6, 6 of the foam product 5 are compressed in the U-shaped cross-sectional direction in the range of the above-mentioned surplus portion,
The foam product 5 is provided with the concave portions 16 and 17 of the lower die block 15.
Pressed to. As a result, as shown in FIG.
The half-finished end 6 is trimmed into a straight shape 7, the outer shape matches the recesses 16 and 17, and a restriking product 9 in which a welding groove 8 is formed in the shape 7 is manufactured.

More specifically, when the half-end portion 6 of the foam product 5 is restricated (either hot or cold) using the lower die block 15 and the upper punch 20, FIG.
In order to avoid cracks and shrinkage during press working from (a) to FIG. 1 (b), the R of the square concave portion 16 of the lower die block 15 is reduced.
R1 of the corner of the foam product 5 set to be larger than 2
However, the R of the square concave portion 16 is changed by the restriking shown in FIG.
It is pressed against 2 and becomes smaller. Thereby, the section modulus increases and the bending rigidity improves.

Here, the restriking is performed by compressing the left and right halved ends 6, 6 of the foam product 5 in a U-shaped cross-sectional direction, and by pressing the foam product 5 into the rectangular recess 16 of the lower die block 15. Since it is pressed against R2, when R1 is reduced, cracking or flesh-off does not occur. Further, R2 of the lower die block 15 and R of the square convex portion 25 of the upper punch 20 are set.
3, the extra material is pushed into the gap, and the corner 29
Increases in thickness, and the bending rigidity is further improved.

In the round section of the foam product 5 shown in FIG. 4, a round recess 17 of the lower die block 15 is formed.
An interval t3 between the upper punch 20 and the round convex portion 26 is set to be larger than a plate thickness t2 of the foam product 5. For this reason,
When the half-end portion 6 of the foam product 5 is restricated, excess material is compressed in the U-shaped cross-sectional direction and the space t3
, And the thickness of the restlike product 9 is changed from t2 to t3.
To increase. Thereby, the fatigue strength is improved.

At this time, since the shape of the foam product 5 is originally a round cross section and the material 4 is thicker than 10 mm, the work does not buckle even when the left and right halved ends 6 are restricked. Concave part 1 of lower die block 15 in outer shape
It is pressed against 7 and completely adapts. Therefore, not only the plate thickness is increased, but also the roundness of the product is improved. In addition, the round convex part 2
The gap 30 between the workpiece 6 and the workpiece may not be provided.

As described above, the axle case 3 obtained by the present manufacturing method can reduce the R of the angular cross section 1 in FIG. Since the thickness t can be increased,
Bending rigidity is improved and fatigue strength is improved. Conversely, if the rigidity is the same as that of the conventional product, the thickness of the material 4 can be made thinner than before, and the weight and cost can be reduced.

Further, since the half-end portion 6 of the foam product 5 is straightened by restriking instead of trimming by conventional gas cutting, there is no useless weld cut portion, and the material yield is reduced. 100%. Also, neither thermal deformation due to gas cutting nor necessity of slag treatment is required. In addition, the half-finished end 6 is prepared by this resilience, and at the same time, the foam product 5 is moved to the lower die block 15.
Since it is pressed against the concave portions 16 and 17 and deformed, it is possible to obtain a restriking product 9 with high dimensional accuracy. Therefore, by welding this as shown in FIG. 1 (d), a highly accurate axle case 1 can be manufactured. In the figure, reference numeral 31 denotes a butt weld (penetration of 100%).

In FIG. 1 (c), the restriking of the angular section 22 and the round section 23 is performed simultaneously, so that the number of steps is not increased as compared with the conventional method. FIG.
Pressing from (a) to Fig. 1 (b) and Fig. 1 (b) from Fig. 1 (c)
May be performed at the same time to reduce the number of man-hours. In this case, it is desirable to perform hot working because the deformation amount is large.

FIGS. 5 and 6 show modified examples.

In this modified example, the above-mentioned foam product 5 is formed by press working so as to have an uneven portion 32 in the center of the cross section along the longitudinal direction. By performing the process on the uneven portion 32, the plate thickness t <b> 4 of the central portion 33 of the cross section of the restlike product 9 is made thicker than other portions. In the drawing, t1 and t2 are the same as the plate thickness of the material 4.

That is, in this modification, the cross section of the foam product 5 shown in FIG. 1B is pressed as shown in FIGS. 5A and 6A, and the foam product 5 is used in the previous embodiment. The upper and lower dies 20, 15 shown in FIG. 3 and FIG.
Intensively compressed, the central part 3
3 is made thicker than the other portions.

As shown in FIG. 1 (d), two pieces of the restlike article 9 are welded to form an upper and lower axle case body including a central angular section 1 and round sections 2 at both ends. An axle case 3 having a thick portion having a plate thickness t4 along the longitudinal direction of the case main body can be obtained.
According to this axle case 3, since the plate thickness t4 of the cross-sectional central portion 33 which is the maximum stress generating portion is thicker than the welded portion 31 side which is the minimum stress generating portion, the plate thickness distribution becomes appropriate as a strength member. The rigidity is further improved.

[0033]

As described above, according to the axle case manufacturing method and axle case according to the present invention, the following effects can be obtained.

(1) An axle case with high dimensional accuracy can be manufactured without deteriorating the material yield.

(2) Bending rigidity and fatigue strength can be improved while reducing the weight of the axle case.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a manufacturing process of an axle case.

2 (a) is a sectional view taken along line aa of FIG. 1 (c), FIG.
(b) shows a sectional view taken along the line bb.

FIG. 3 is a cross-sectional view showing a state of restric- tion at a corner cross-section.

FIG. 4 is a cross-sectional view showing a state of restriking of a circular cross-section.

FIG. 5 is a cross-sectional view showing a state of restriking at a corner cross-section showing a modification.

FIG. 6 is a cross-sectional view showing a state of a restriking of a circular cross-section showing a modification.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Square cross section 2 Round cross section 3 Axle case 4 Material 5 Foam product 6 Half-split end 9 Restlike product 15 Lower mold 20 Upper mold 32 Unevenness

Claims (8)

[Claims] 1. A foam product having a shape in which an axle case is divided in half is sandwiched between an upper mold and a lower mold, and a half-divided end portion of the foam product is restriated to thereby reduce the shape of the foam product. A method of manufacturing an axle case that deforms according to the upper and lower molds, straightens the halved ends, and welds the two restri-like products at the halved ends. 2. The method for manufacturing an axle case according to claim 1, wherein the thickness of the restric-like product is made larger than the thickness of the foam product by the restriking. 3. The method of manufacturing an axle case according to claim 1, wherein the R of the angular cross section of the foam product is smaller than the R of the angular cross section of the foam product by the restriking. 4. The method of manufacturing an axle case according to claim 1, wherein a groove for welding is formed at a half-split end of the foam product by the restriking. 5. The method for manufacturing an axle case according to claim 1, wherein said foam product is formed by pressing a rectangular flat material. 6. The foam product is formed into a square cross-section at the center in the longitudinal direction, and both ends are formed into a round cross-section.
2. The method of manufacturing an axle case according to claim 1, wherein R is further reduced, the plate thickness of the round cross section is increased, and a welding groove is formed at a half-split end to obtain a restri-like product. 7. The foam product is formed so as to have an uneven portion along a longitudinal direction at a central portion of a cross section thereof, and the restrike is formed on the uneven portion in addition to the half-end portion. 2. The method of manufacturing an axle case according to claim 1, wherein the thickness of the central portion of the cross section of the restlike product is made thicker than other portions. 8. An axle case main body is formed from a central angular cross section and a round cross section at both ends thereof, and thick portions are formed at upper and lower portions of the axle case main body along the longitudinal direction of the case main body. An axle case characterized by: