JP2001001063A - Thickness-reduced material and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the production method of a thickness-reduced material capable of simplifying a production process and having a high material yield by performing ironing to a peripheral wall, while an ironing die and a stock are relatively moved, to at least a part of the stock in the axial direction, and forming a thickness-reduced part to the worked part. SOLUTION: An ironing die 20 to form a thickness-reduced part 11 is the split dies bisecting a peripheral wall in the peripheral direction. Ironing is performed by that the ironing part 21 of the ironing die 20 is butted on the part to be worked of the outer peripheral wall of a stock 1, the stock 1 is moved up to a working completion position (arrow mark PA) while fixing the position of the die 20, or the ironing die 20 is moved to a working completion position (arrow mark PB) by the stock 1. The ironing die 20 and the stock 1 are required to relatively move, force (PC) is imparted in the relative advancing direction of the stock 1, thus, the ironing force is reduced, the dimensional precision and shape stability of a worked part are improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hollow material having a reduced peripheral wall thickness at least in a part of the axial direction and a method for producing the hollow material.

[0002]

2. Description of the Related Art Like a vehicle arm member, a metal hollow material having a partially different wall thickness and cross-sectional shape in the axial direction is made of a hollow material having a maximum cross-sectional area as a base material. It was common to manufacture by cutting off.

[0003]

However, in the above-mentioned method, there is a problem that it takes a long time to process and chips are generated, so that a processing operation and a processing cost are required. There is also a problem that the material in the removed portion is wasted and the material yield is low.

The present invention has been made in view of such technical background,
It is an object of the present invention to provide a thinned material having a simplified production process and a good material yield, and a method for producing the same.

[0005]

In order to achieve the above object, the present invention provides a thinned part (1) whose peripheral wall is thinned by ironing at least in a part of the axial direction.
It is characterized by having 1).

[0006] Further, the method for producing a thinned material comprises an ironing die (2) in at least a part of the base material (1) in the axial direction.
The basic gist is to relatively move the base material (0) and the base material (1) to perform ironing on the peripheral wall to form a reduced thickness portion (11) in the processed portion. Further, in the manufacturing method, as the ironing die (20),
It is preferable to use a split mold that is divided in the circumferential direction and has a parting line (L) formed at the position of the axis and the twist. Further, the base material (1) is a hollow base material (3), and ironing is performed in a state where another member (2) is inserted and arranged in a hollow portion of the hollow base material (3). It is preferable to join (3) and another member (2). Furthermore, the ironing process is performed in the ironing part (6
A plurality of ironing dies (61) (63) (65) in which the maximum aperture of (0) (62) (64) corresponds to the minimum diameter of the planned processing position of the substrate (50), and the aperture diameter gradually decreases. ) Is preferably performed a plurality of times.

[0007]

FIG. 1 shows an example of a method for producing a thinned material according to the present invention. In this example, as shown in FIG. 2, a cylindrical tube having an outer diameter Ra is used as a base material (1), and
Then, the outer peripheral wall of the intermediate portion in the axial direction is squeezed to produce a thinned material (10) having a thinned portion (11) reduced in outer diameter Rb.

The ironing die (20) forming the thinned portion (11) is a split die whose peripheral wall is divided into two in the circumferential direction as shown in FIG. 3, and when the die is closed, the ironing die (20) is ironed. The opening of the portion (21) has a circular shape corresponding to the outer peripheral shape of the thinned portion (11).

In the ironing process, the ironing portion (21) of the ironing die (20) is applied to a portion to be processed of the outer peripheral wall of the substrate (1), and the position of the die (20) is fixed and the substrate (1) is fixed. ) To the processing end position (arrow P _A ), or by moving the ironing die (20) on the substrate (1) to the processing end position (arrow P _B ). Ironing dies (2
0) and the substrate (1) may be moved relatively. Processing can be performed by fixing one and moving the other, but force is applied in the relative traveling direction of the substrate (1). By adding (P _C ), the ironing power is reduced, and the dimensional accuracy and shape stability of the processed part can be improved.

[0010] Since the present invention is based on ironing, the thinned portion can be formed only by the relative movement of the die, and no chips are generated, thereby simplifying the manufacturing process. In addition, the ironed part of the thinned part improves the surface hardness and strength by work hardening,
The effect of compensating for a decrease in strength due to wall thinning is obtained.

In the present invention, it does not matter whether the thinned material is a hollow thinned material (10) as shown in FIG. 1 or the like or a solid thinned material. Therefore, the substrate (1) may be hollow or solid, and may have any cross-sectional shape. Further, the cross-sectional shape of the thinned portion (11) by ironing is not limited, and in addition to a simple diameter reduction in which the thickness is reduced uniformly over the entire circumference of the base material (1) as shown in FIG. The elliptical shape shown in (A), (B) and (C) (1
5), a polygon (16), a thinned portion (19) having a projection (17) or a groove (18), and the like. Further, even if the shape of the thinned portion is complicated, only the shape of the ironing die is changed, so that the ironing process itself is not complicated.

However, when the difference in thickness (R _A -R _B ) from the base material (1) to the thinned portion (11) is extremely large, a large ironing work force is required, resulting in a decrease in dimensional accuracy and damage. Cause. For this reason, it is preferable to use a plurality of ironing dies in which the size of the ironing portion is different in a stepwise manner and perform the ironing process a plurality of times while reducing the amount of deformation per operation. Also,
Even when the degree of deformation is large, such as when processing a base material with a circular cross section into a polygon, the thickness reduction rate increases locally, so ironing is performed multiple times using an ironing die with an intermediate shape. It is preferable to process it into a target shape. As will be described in detail later, it is also effective to reduce the deformation resistance itself by heating the processed portion.

The position where the ironing process is performed on the base material (1) may be on the end portion or on the entire length in addition to the axially intermediate portion as shown in FIG. Moreover, you may give to several places. In the case where the thinned portions are formed at a plurality of positions, they do not need to have the same cross-sectional shape, and can be processed into different shapes. In particular, a thinned material in which a thinned portion is formed in an intermediate portion of a base material and a thickened portion is left at an end is required for a vehicle or the like in which strength is required at an end of a pipe and reduction in weight of a member is required. It is suitable as various arm materials.

The materials of the thinner and the substrate (1) are not particularly limited as long as they are ductile enough to allow ironing. Aluminum or an alloy thereof can be exemplified as a material having excellent ductility and suitable for ironing, and in particular, JIS 606
A 600 series alloy such as 3,6N01,6061 can be recommended.

For materials having high deformation resistance,
The application of the ironing process can be facilitated by heating the processed portion of the base material to reduce the deformation resistance. In addition, by lowering the deformation resistance, it is possible to perform processing with a much higher rate of thickness reduction. The method of heating the hollow substrate and the heat source are not particularly limited. For example, in the processing example of FIG. 1, a heating device such as a high-frequency heating device (40) is arranged in front of the ironing die (20) and moves together with the die (20). The parts to be processed are sequentially heated.

When a split die whose peripheral wall is divided in the axial direction is used as the ironing die (20), if a slight gap is formed in the parting line, the ironed material flows into the gap with the ironing. Sometimes. In such a case, if the parting line (L) in the axial direction is parallel to the axis as shown in FIG. 3, the parting line (L) on the peripheral surface of the base material (1) moves along the ironing direction. There is a risk that the material that has been moved and squeezed in a straight line will continuously flow into the gap, and the material that has flowed will swell on the surface of the processed portion, making it impossible to form an ironed shape accurately. However, if the parting line (L) is located at the position of the axis and the twist, the parting line (L) moves on the outer peripheral surface of the base material (1) so as to cross the ironing direction. Continuous flow into the gap of the line (L) is prevented, and no swelling due to the parting line (L) occurs in the processed part.

FIGS. 4 and 5 show examples of split molds in which the parting line (L) is formed at the position of the axis and the twist.
The parting line (L ') for the split mold (30) shown in FIG.
Is tilted before and after the ironing direction, so that the entire parting line (L ′) is in a twisted position. Also, in the split mold (35) shown in Fig. 5, the parting line (L ") is curved at the center, and only the curved portion (36) is at the twist position. The swell can be eliminated by cutting off the continuous flow into the gap, and the parting line (L ') (L ")
It is possible if at least a part of is formed at the position of the twist.

Further, when the substrate (1) is a hollow substrate (3), as shown in FIG. 7, a hollow or solid separate member ( If 2) is inserted, these members (3) and (2) can be joined by the residual stress generated at the boundary between the members (3) and (2). Since joining is achieved at the same time as ironing, no extra work is required for joining. At this time, another member (2)
The bonding force can be increased by forming spiral or ring-shaped grooves or projections on the outer peripheral surface of.
A composite material formed by joining such separate members has excellent strength and is suitably used for various arm materials for vehicles and the like.

When an ironing die is set on a substrate, it is necessary to previously form a groove corresponding to the shape of the ironing portion of the die at the processing start position of the substrate, and such preprocessing is performed by cutting or rolling. It is appropriately performed by the above. However, the maximum opening diameter of the ironing part corresponds to the minimum diameter of the scheduled processing position of the base material,
In addition, by using a plurality of ironing dies whose opening diameter gradually decreases, a required thinned portion can be formed only by ironing a plurality of times without performing pre-processing.

Here, as an example of processing without pre-processing, a cross-sectional ellipse of maximum diameter D ₂ × minimum diameter D ₃ (D ₀ > D ₂ > D ₃ ) is applied to a circular base material having an outer diameter D _0. A method of forming the reduced thickness portion by three ironing operations will be described with reference to FIG. Each of the ironing dies used was of the same type as the die (20) shown in FIG. 3, and only a side view is shown.

First Ironing Process As shown in FIG. 8A, the opening of the ironing portion (60) is orthogonal to the outer diameter, that is, the base material (50) having a maximum diameter and a minimum diameter of D _0. using the maximum diameter D ₀ × minimum diameter D ₁ (D _0> D ₁₎ a first ironing die (61) of the elliptical shape of the. Since the outer diameter of the base material (50) is equal to the maximum diameter D0 of the opening of the ironing portion (60), the ironing portion (60) of the first ironing die (61) is set at the position where the base material is to be processed. Can be started. Then, by this ironing, FIG.
First intermediate material having a maximum diameter D ₀ × thinning of the elliptical cross-sectional shape of the minimum diameter D ₁ shown in (B) a (51) (52) is formed. The maximum wall thickness reduction in the first ironing (δ ₁ max
) Is δ ₁ = D ₀ −D ₁ , and the minimum thinning amount (δ ₁ min
) Is δ ₁ min = D ₀ −D ₀ = 0.

Second Ironing Process As shown in FIG. 8B, a first intermediate member (52) having a thinned portion (51) having an elliptical cross section with a maximum diameter D ₀ × a minimum diameter D ₁ is provided. opening of the ironing section (62) uses the maximum diameter D ₁ × minimum diameter D ₂ (D _1> D ₂₎ a second ironing die (63) of the elliptical shape of the perpendicular. In the second ironing die (63), the minimum diameter D ₁ of the thinned portion (51) of the first intermediate material (52).
Is the maximum diameter D of the ironing portion (62) of the second ironing die (63)
Because they are equal to ₁ , the _first to match these positions
If the intermediate member (52) is rotated by 90 °, the first intermediate member (52)
A second ironing die (63) can be set in the thinned part (51) of the first intermediate member (52), and the portion of the maximum diameter (D ₀ ) of the first intermediate material (52) is the minimum opening diameter of the second ironing die (63). According to the portion of (D ₂ ), the thinned portion (51) can be further ironed. By this ironing, the maximum diameter D ₀ is thinning in D _2, reduction of the oval cross section of maximum diameter D ₁ × minimum diameter D ₂ of the reduced thickness portion of the first intermediate member (52) (51) A second intermediate material (54) having a meat portion (53) is formed. The maximum wall loss (δ ₂ max) in the _second ironing is δ ₂ ma
x = D ₀ −D ₂ , and the minimum thinning amount (δ ₂ min) is δ ₂ mi
n = D1 -D1 = 0.

Third Ironing As shown in FIG. 8C, a second intermediate member (54) having a thinned portion (53) having an elliptical cross section with a maximum diameter D _{1 and a} minimum diameter D ₂ is provided. An elliptical third ironing die (65) having a maximum diameter D ₂ × minimum diameter D ₃ (D ₂ > D ₃ ) where openings of the ironing portion (64) are orthogonal to each other is used. In the third ironing die (65),
For equal to the maximum diameter D ₂ of the minimum diameter D ₂ are ironing portion of the third ironing die (65) of reduced thickness portion (53) of the second intermediate member (54) (64), the partial match these positions If the second intermediate member (54) is rotated by 90 ° so that the second intermediate member (54) is rotated, the third ironing die (65) can be set in the thinned portion (53) of the second intermediate member (54). The maximum diameter (D ₁ ) of the material (54)
The minimum opening diameter of the third ironing die (65) (D ₃ )
And ironing can be further performed on the thinned portion (53). And by this ironing process,
Maximum diameter D ₁ of the reduced thickness portion of the second intermediate member (54) (53) is reduced meat D _3, thinning material having a reduced thickness portion of the oval cross section of maximum diameter D ₂ × minimum diameter D ₃ Is formed. The maximum thinning amount (δ ₃ max) in the _third ironing is δ ₃ max = D ₁ −D
₃ , and the minimum wall loss (δ ₃ min) is δ ₃ min = D ₂ −
D ₂ = 0.

As described above, by using a plurality of ironing dies having an opening diameter corresponding to the base material, it is possible to set an ironing die without performing any pre-processing such as cutting, and to form a thinned portion only by ironing. And the process is simplified. In the processing example described above, the thinned portion having an elliptical cross section is formed. However, the present invention does not limit the shape of the thinned portion, and the required cross-sectional shape may be formed according to the opening shape of the ironing portion. Can be.

[0025]

EXAMPLE (Example 1) As shown in FIG.
A 601 aluminum alloy, 50 mm outside diameter and 5 mm thick hollow cross-section hollow base material
An ironing process was performed to reduce the thickness in the circumferential direction in the middle part in the axial direction. As the ironing die, a split die (30) shown in FIG. 4 in which a parting line (L ') was inclined before and after the ironing direction and divided at the axis and the twist position was used. The hollow base material (1) is cut into a groove by cutting at the processing start position, and the ironing portion (3) of the ironing die (30) is formed in the groove.
1) was set. The ironing was performed once to reduce the wall thickness by 1 mm to produce a wall-thinning material (10) having a wall-thinning portion (11) having a circular cross section.

(Example 2) JIS harder than Example 1
Ironing was performed on a hollow substrate made of A6061 aluminum alloy. The shape of the base material, the dies used, and the amount of wall thinning were the same as in Example 1, but a high-frequency heating device was arranged in front of the ironing dies, and ironing was performed while heating.

(Embodiment 3) As shown in FIG.
The same ironing as in Example 1 was performed in a state where another hollow member (2) made of SUS304 and having an outer diameter of 40 mm and a thickness of 1 mm was inserted and placed in the same hollow base material (3).

(Embodiment 4) As shown in FIG.
3mm ironing dies (61) (61) with different opening diameters of ironing portions (60) (62) (64) without pre-processing on a hollow substrate (50) having a circular cross section with a thickness of 5 mm and a wall thickness of 5 mm 63) and (65) were sequentially set on the processed portion of the base material (50), and ironing was performed three times to form a thinned portion having an elliptical cross section. The opening diameters of the three ironing dies used are as follows.

The maximum opening diameter (D ₀ ) of the first ironing die (61) and the ironing portion (60): 50 mm The minimum opening diameter (D ₁ ): 48 mm The maximum opening diameter of the second ironing die (63) and the ironing portion (62) (D ₁ ): 48 mm Minimum opening diameter (D ₂ ): 46 mm Maximum opening diameter (D ₂ ) of the third ironing die (65) and ironing portion (64): 44 mm Minimum opening diameter (D ₃ ): 44 mm Each of the thinned materials manufactured in the examples had a thinned portion having a desired cross-sectional shape formed well. In particular, the wall-thinning materials of Examples 1 to 3 did not show any swelling due to the flow of the material into the parting line of the die, and had good appearance quality. Further, in the thinned material of Example 3, the base material and another member were favorably joined. further,
In Example 4, the pre-processing for setting the ironing die was not required, and the process could be simplified.

[0030]

As described above, the reduced thickness material of the present invention has a reduced thickness portion whose peripheral wall is reduced by ironing at least in a part of the axial direction. The hardness and strength of the surface are improved by hardening, and the reduced strength is compensated for by reducing the thickness. In particular, a thinned material in which a thin-walled portion is formed only in the middle part of the base material and a thick-walled portion is left at the end is required to have strength at the end of the pipe and to reduce the weight of the member. It can be suitably used as an arm material.

In the method for producing a thinned material according to the present invention, at least a part of the substrate in the axial direction is relatively moved between the ironing die and the substrate to perform ironing on the peripheral wall. Since the reduced thickness portion is formed in the processed portion, the reduced thickness portion can be formed only by the process of moving the die, and the manufacturing process is simplified.
Further, unlike the conventional thinning by cutting, no chips are generated, so that chip processing is not required, thereby simplifying the manufacturing process and improving the material yield.

In the manufacturing method, the ironing die may be divided in the circumferential direction, and the parting line may be formed at the position of the axis and the twist. Continuous flowing into the processed part is prevented, no swelling occurs due to the parting line in the processed part, and a thinned material having good appearance quality can be obtained.

Further, a hollow substrate is used as the substrate,
Ironing is performed in a state where another member is inserted and arranged in the hollow portion of the hollow base material, and by joining the hollow base material and another member, thinning and joining can be performed simultaneously, without increasing the number of steps. A composite material having excellent strength can be obtained.

Further, the ironing is performed a plurality of times by using a plurality of ironing dies in which the maximum opening diameter of the ironing portion corresponds to the minimum diameter of the planned processing position of the base material and the opening diameter gradually decreases. This makes it possible to form the thinned portion having the required cross-sectional shape without the pre-processing for setting the ironing die, so that only the ironing is performed, and the process can be simplified.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an example of a method for producing a thinned material according to the present invention.

FIG. 2 is a cross-sectional view showing an example of a thinning material.

3A and 3B show an example of an ironing die, in which FIG. 3A is a longitudinal sectional view and FIG. 3B is a side view.

4A and 4B show another example of the ironing die, wherein FIG. 4A is a longitudinal sectional view and FIG. 4B is a side view.

5A and 5B show still another example of the ironing die, wherein FIG. 5A is a longitudinal sectional view and FIG. 5B is a side view.

FIGS. 6A, 6B, and 6C are cross-sectional views showing other examples of the thinned portion.

FIG. 7 is a longitudinal sectional view showing another example of the method for producing a thinned material according to the present invention.

FIG. 8 is a view showing three steps of ironing steps (A), (B), and (C) in which the thickness is reduced without a pre-processing for setting an ironing die in the method for producing a thinning material of the present invention. FIG. 3 is a cross-sectional view of a base material to be processed in each step and a side view of an ironing die.

[Explanation of symbols]

 1, 3, 50: Base material (hollow base material) 2: Separate member 10: Reducing material 11: Reducing portion 20, 30, 61, 63, 65 ... Ironing dies 21, 60, 62, 64 ... Ironing portion L , L ', L "... parting line

Claims (5)

[Claims] 1. A wall-thinning material characterized by having a wall-thinning portion (11) whose peripheral wall is thinned by ironing in at least a part in the axial direction. 2. An ironing process is performed on at least a part of the substrate (1) in the axial direction by relatively moving the ironing die (20) and the substrate (1) to iron the peripheral wall.
A method for producing a thinned material, comprising forming a thinned portion (11) in the processed portion. 3. The reduction die according to claim 2, wherein the ironing die (20) is split in a circumferential direction, and a parting line (L) is formed at an axis and a twist position. How to make meat. 4. The method according to claim 1, wherein the substrate is a hollow substrate (3), and ironing is performed in a state where another member (2) is inserted and arranged in a hollow portion of the hollow substrate (3). The method for producing a thinned material according to claim 2 or 3, wherein (3) and another member (2) are joined. 5. The ironing process includes the steps of:
2) A plurality of ironing dies (61) (63) (65) whose maximum opening diameter of (64) corresponds to the minimum diameter of the planned processing position of the substrate (50) and whose opening diameter gradually decreases The method for producing a thinned material according to any one of claims 2 to 4, wherein the method is performed a plurality of times.