JPH0710408B2 - Method and apparatus for forging of variable cross section - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a forming method and apparatus for forming a variable cross-section long product having a twist and a cross-sectional shape that is asymmetrical in the vertical and horizontal directions by forging.

[Conventional technology]

Conventionally, molding of long products with such complicated shapes is
Forging is performed using a die that can form the entire shape of long products. The conventional molding method is shown in FIGS. 13 to 16. Of these, FIGS. 13 to 15 show molding patterns of materials, and FIG. 16 shows the apparatus. The molding method will be described. Fig. 13 shows the basic material, Fig. 14 shows the primary material before forging, and Fig. 15 shows the shape after forging. In Fig. 13, the shape of the basic material is calculated based on the idea that the volume after forging is constant. The primary material shape with a circular cross section in Fig. 14 is that the product is a long product in the longitudinal direction. Therefore, the cross-sectional area in the width direction is the final product based on the idea that all the material of the material flows in the width direction during forging. The diameter of the circular cross section is calculated with the same dimensions. The primary material having the shape shown in FIG. 14 is machined or forged from the basic material shown in FIG. The formed primary material 1 is set in the lower mold 2 of the apparatus shown in FIG. 16, and the upper mold 4 is lowered by the driving device via the screw 3, and the primary material is placed in the upper mold 4 and the lower mold 2. Insert 1 to form the product shape shown in Fig. 15 along the mold. The equipment is composed of an upper mold 4 and a lower mold 2 in the entire frame 5.
Is set by using the sliding portion 6 as a guide, and the upper die 4 is connected to the drive device 7 via the screw 3 so that the upper die 4 can be moved up and down. In the case of this conventional method and apparatus, since the forging process is performed by using the full die, the required machining force is very large, the cost of the die made by one piece is expensive, and the number of days for producing the die is large. There is such a problem.

As another processing method, as described in Japanese Patent Publication No. 59-11375, there is a method in which different upper molds are sequentially added to the workpiece, but basically, the upper mold and the lower mold are all combined. Required,
It becomes expensive. Further, the processing force is not so small because the upper die finally contacts the entire shape area of the long product.

[Problems to be Solved by the Invention]

As described above, the conventional technology has a problem that the processing force required for molding is large and the mold shape is complicated, which requires a long number of days to manufacture the mold and the cost of the mold is high.

[Means for Solving the Problems]

The forge forming method of the present invention does not use a full die, but uses a die corresponding to each of a plurality of divisions in the longitudinal direction of a long product. This section must be sufficiently small in the longitudinal direction, and therefore the number of divisions must be large enough. The molds used are the opposite molds. Then, forging is performed for each section continuously in the longitudinal direction. In this forging, molds having different shapes are used at the places where the cross section of the long product changes in the longitudinal direction. It is important to restrain both ends of the raw material that is the base material of the long product in order to absorb the bending caused by forging and to give a twist angle determined for each cross section in each case. First, the longitudinal direction is the x-axis direction, the forging direction is the y-axis direction, and the direction orthogonal to the x-axis direction and the y-axis direction is the z-axis direction. The restraint on one end side is performed in the y-axis direction, the z-axis direction, and around the x-axis. The other end is constrained in the y-axis direction and the z-axis direction. Of the restraints on the one end side, the restraint about the x-axis is performed in order to give a predetermined twist angle in the section for forging in advance. This twist angle is determined so as to satisfy the twist angle required for each cross section, and is given as the twist angle with respect to the one end side.

The forge forming apparatus of the present invention is an apparatus used for carrying out the forge forming method. That is, the opposing dies having the die shape corresponding to each of the plurality of divisions in the longitudinal direction of the long product include the upper die and the lower die. The forging device having the die is configured to be movable in the longitudinal direction, so that the forging can be continuously performed in each of the sections in the longitudinal direction. The two ends of the material of the long product are constrained by two manipulators. This manipulator has a clamp arm for clamping the end of a long product. One of the two clamp arms has a structure that can be fixed at an arbitrary rotation angle around the longitudinal axis, that is, around the x axis. The other clamp arm has a structure that is freely rotatable around the longitudinal axis, that is, around the x axis.

[Action]

Longitudinal products are divided into a plurality of sections in the longitudinal direction and have opposite molds (hereinafter referred to as sectional dies) that have a shape corresponding to each section, and by forging each section continuously in the longitudinal direction, You don't need a pattern like When forging is performed by such a sectional die, a long product having a cross-sectional shape that is asymmetrical in the vertical and horizontal directions is bent vertically (y-axis direction) or left-right (z-axis direction) at each forging. . Further, when a predetermined twist is required for the long product as a whole, it is not possible to work well only with the sectional type. The above problems regarding bending and twisting have been solved by devising restraints on both ends of a long product. That is, regarding the up and down and left and right bends, the y-axis direction and the z-axis direction are restrained at both ends to forcibly prevent the bend. Note that the x-axis direction is not constrained because a material flow occurs. Also, about the y-axis and the z-axis, both ends are constrained. About the x-axis, one end side is given a twist angle with respect to the one end in advance, and forging is performed in this given state. As a result, due to the phenomenon of so-called plastic joint, the twist angle is given only to the section to be forged. That is, at the moment when forging is performed, the material is in a yield state in that section and loses elasticity against torsion. The forging process is always performed in a fixed direction, for example, in the vertical direction. X on the other end
The material can freely rotate during forging without restraint about the axis.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 2 to 6 show changes in shape from material to product. FIG. 5 shows the shape of the final product manufactured by the present invention. The cross-sectional shape has a to and also longitudinally example theta ₁ ° in B section, a shape twisted relative to the root portion N so that theta ₂ ° in C cross section asymmetric.

As a molding method, first, the entire volume is calculated from the final product shape shown in FIG. 5, and the basic material is cut so that the volume becomes the same with the round material (diameter D, length L ₁ ) having the shape shown in FIG. At this time, the basic material may be round or square. The material used in this example had a diameter of 160 mm and a length of 1.5 m to 2 m.

This basic material is formed into the primary material shown in FIG. For the molding, the upper and lower molds that have flat contacting parts are used. As a narrow mold with a sufficient width in the longitudinal direction, the upper and lower molds sandwich the basic material. The primary material has a width having the same dimensions as the widths W ₀ and B ₀ in the cross section of the final product shown in FIG. 5, and has a height h _{0 including the} height dimension in the cross section of the final product. _{It has} a rectangular cross section of ₀ × h ₀ (see the A ₀ and C ₀ cross sections in the figure).
Amount obtained by subtracting the sectional area of the product from this rectangular section (hatched area)
However, they all flow in the longitudinal direction during forging. Also, the length L2 is determined by the principle of constant volume. When the width dimension and the thickness dimension of the primary material change in the longitudinal direction to W ₀ → B ₀ , h ₀ → S ₀ , these are linearly connected and molded as a guide.

Next, the secondary material shown in FIG. 4 is formed. This molding is
It depends on a mold having a mold shape corresponding to each of a plurality of divided sections in the longitudinal direction of the product (referred to as a section type). This sectioned mold is composed of an upper mold and a lower mold, and the length in the longitudinal direction is sufficiently small. Using this segmented mold, the primary material is sandwiched in between to perform molding. When the molding at a certain cross-sectional position is completed, the position in the longitudinal direction is changed and the molding is successively performed for each section. If the cross-section changes extremely in the longitudinal direction, it can be dealt with by changing the mold. Also in this case, since the mold corresponds to the segmented mold having a sufficiently small length as described above, the problem as in the case of using the total mold is solved. In other cases, that is, when the change in cross-sectional shape in the longitudinal direction is not extreme and only the thickness changes, molding can be performed by using the same mold and controlling the stroke positions of the upper mold and the lower mold. . At this time, since the cross-sectional shape of the product is asymmetrical, bending occurs in the up-down direction (y-axis direction) and the left-right direction (z-axis direction). This is caused by restraint of the mold itself and the y-axis direction of both ends of the secondary material. Prevent by z-axis restraint.

Next, the final product shown in FIG. 5 is molded. In FIG. 4, the final molding size is left with a finishing allowance of 1 to 2 mm. In the forming of FIG. 5, considering the root portion N as a reference, for example, when a twist angle θ ₁ is required in the cross section in the longitudinal direction B, the entire secondary material is rotated to θ ₁ , and in this state, the processing portion The upper die and the lower die are set at the position of the B ₂ cross section so that they are rotated by 0 ° with respect to the root portion N, and forged. At this time, the secondary material is equivalent to the finishing allowance (h ₁ −h ₀ , S ₁ −
The material undergoes forging only S ₀ ) and the material becomes in a yield state. Further, in this yield state, since the twist represented by the twist angle θ _{1 is received} , the twist is formed by a small twisting force. At this time, no twist is formed in the other sections that are not in the yield state, and the required twist angle in the cross section can be accurately formed. The fact that the vertical processing stress creates a yield state even with respect to the movement in the twisting direction (around the x-axis) can be simply explained by the expression of the Mises yield condition. First, the minute cube of the material in the section where the forging is performed is taken out and the stress is expressed as shown in FIG. At this time, the yielding condition of the material is expressed by the following formula.

(Σx−σy) ² + (σy−σz) ² + (σz−σx)
^{2 +6 (τyz 2 + τzx 2} + τxy 2) = 2Y 2 where Y is the tensile yield stress.

As can be seen from this equation, if the working force by vertical forging, that is, the stress σy is sufficiently large, the yield state of the material can be obtained even if τxy and τxz related to the torsional force are small. A state in which the material loses resistance to a processing force such as twisting in such a section where forging is performed is called a plastic joint. For example, considering the state of rolling,
The portion where the material is rolled just below the rolling roll is the portion to which the processing force is applied by the roll, and this portion has a lower material strength than the other portions. Generally, it depends on the rolling reduction, but it is smaller than 1/10. In the rolling process, this part is called a plastic joint. A plastic joint can be formed by locally heating in addition to applying a working force.

By continuously performing the forging process with this segmented die at the longitudinal position, an accurate twisted shape is given to the entire product. At this time, the amount of finishing allowance to be forged is small, but since the cross section is asymmetric, bending occurs as in the case of FIG. Therefore, the secondary material is restrained to prevent bending, and at the same time the rotation around the x-axis is made free so that the tip of the secondary material can rotate during molding with the upper and lower molds.

Next, an example of an apparatus for carrying out the present processing method will be described. Fig. 1 shows the overall view, but the device configuration is
A manipulator 12 for handling the material 11 is provided on the right, and a forging device 13 for molding the material 11 is provided between them. The manipulator 12 is substantially the same as the left and right, and details are shown in FIGS. 7 and 8. The manipulator 12 has a clamp arm 14 that can move in the x-axis direction, the y-axis direction, and around the x-axis.

First, the structure of the clamp arm 14 that clamps the material is such that the clamp contact portion 15 is connected to the clamp arm 14 via the pin 16, the clamp arm 14 is connected to the clamp shaft 18 via the pin 17, and the clamp shaft 18 is , Is contacted to the clamp cylinder 19. The position of the clamp arm 14 is determined by the pin 20, and the pin 20 is fixed to the face plate 21. The face plate 21 is a frame 23 with a cushion material 22 in between.
Supported by. The clamp shaft 18 can be moved in the x-axis direction using the bush 24 as a guide, and the rotational force can be transmitted to the material via the key 25.

The rotation around the x-axis rotates the entire clamp shaft 18 and the rotary shaft 26, and the rotation motor 27 causes the gears 28, 2 to rotate.
8 '. In any of the manipulators, the rotation motor 27 rotates to the rotation angle and holds its position when the power is turned on and the rotation angle is input, and when the power is turned off, the rotation shaft, that is, the clamp shaft 18 freely rotates. Is configured. The rotation of the rotary shaft 26 is transmitted to the clamp shaft 18 and the face plate 21 via the bush 24, and the clamp arm 14 is rotated. The rotating shaft 26 is a bearing 30.
It is held by the frame 31 via.

The movement in the y-axis direction moves the clamp shaft 18, the rotary shaft 26, and the entire frame 31. The moving motor 32 moves the frame 31 in the y-axis direction via the moving shaft 33 with the sliding surface 34 as a guide.

The z-axis movement is performed by moving the entire manipulator, and the drive motor 35 moves the saddle 37 via the drive shaft 36. A sliding surface is attached to the saddle 37 and moves on the pedestal 38.

The movement in the x-axis direction is to move the entire manipulator, and is performed by driving the pedestal 38 via the drive shaft 40 using the sliding surface of the manipulator 39 as a guide. The manipulators having the above functions are installed facing each other.

The rotation of the material about the y-axis at the clamp position is transmitted to the frame 23 via the clamp arm 14, the pin 20, the face plate 21, and the cushion material (hereinafter referred to as a damper) 22, and the frame 23
At 23, this rotation is stopped. The rotation of the material in the clamp position in the z-axis direction is also stopped by the frame 23. In the manipulator generally used for forging,
In this case, there is no one that can freely rotate the material at the clamp positions around the y-axis and the z-axis, but there is no one that has a function of positively restraining the rotation.

Next, the structure of the forging machine will be described with reference to FIG. An upper die driving cylinder 51 and a lower die driving cylinder 52 are attached inside the entire frame 50 via flanges 53 and 54, and an upper die 55 and a lower die 56 are attached to their tip ends, respectively. The upper mold 55 and the lower mold 56 are 200 mm in length (z-axis direction) and 15 mm in width (x-axis direction). Material is JIS G4404 SKD6.
The one used was 1. Further, each mold has a structure that can be moved up and down by using the sliding plate 57 as a guide. Further, on the side surface of the entire frame 50, a guide member 58 which can be moved separately in the left-right direction (z-axis direction) in the vicinity of the upper die and the lower die.
Is installed at the tip of the drive cylinder 59. This guide member 58, as shown in FIG.
6 is arranged at a position shifted in the x-axis direction.

The guide member 58 and two manipulators restrain the material in the z-axis direction.

The operation will be described with reference to FIGS. 10 to 12. First, the basic material (FIG. 2) is set on the left and right manipulators, and the clamp cylinder 14 clamps the clamp arm 14. At this time, the end surface of the basic material is brought into contact with the stopper 18 'for positioning. In this state, a mold having a flat contact surface as shown in FIG. 10 is used for the upper and lower sides to mold the circular shape into a predetermined rectangular shape. This allows the same molding device to be used for pre-processing. At this time, the basic material is rotated 90 degrees to form a rectangle because it is formed from two directions. If the cross section is tapered, the drive cylinder 32 etc. has the function of being able to control any position. Mold. In addition, when the material is formed by forging, it escapes in an unconstrained direction (for example, in the unconstrained width and longitudinal direction when pressed from above and below by a mold) from the principle of constant volume. This is described as the material flowing, for example, the material flowing in the longitudinal direction increases the length of the material. In this embodiment, since the longitudinal end of the material is restrained by the stopper 18 ', the flow of the material in the longitudinal direction due to forging acts as an impact force for pressing the material end against the stopper 18'. This impact force is transmitted to the clamp shaft 18 via the stopper 18 ', and further, the pin 17 and the clamp arm.
14, transmitted to the face plate 21 via the pin 20. The impact force transmitted to the face plate 21 is relaxed by the damper 22 and received by the frame 23. That is, the drive cylinder 39 and the stopper 1
A damper 22 is interposed between 8 ', and when the material end moves the material end portion in the x-axis direction, the damper 22 operates so as to absorb the movement and does not restrain the movement. It has become.

The amount of material flow absorbed by the damper 22 was about 15 mm in the example. Material flow by forging occurs toward both sides of the mold in the x-axis direction. During forging, of the manipulators 12 in FIG. 1, for example, the left manipulator 12 is fixed so as not to move in the x-axis direction, and the other manipulator 12 is fixed.
12 is designed to be freely movable in the x-axis direction. Therefore, the flow of the material to the other manipulator side is not restricted, and is absorbed by the movement of the other manipulator in the x-axis direction (the direction away from the forging device).
The flow of the material to the fixed side manipulator side is absorbed by the compression of the damper 22, but when the mold once pressed against the material is pulled up and down in the forging device 13, the material is
11 is returned to the other manipulator side by the repulsive force of the damper 22, and the damper 22 returns to the initial position and shape. The operation of the damper is repeated each time the press operation is performed.

In forging, instead of forming into a predetermined shape with a single press, the press operation is repeated many times at the same location to form a predetermined shape. Therefore, as shown in FIG. 3, even if the material cross-sectional area after molding is smaller than the material cross-sectional area before molding, the material that flows by molding does not flow in one pressing operation, but multiple times. It is divided into press motions and flows. In other words, it is sufficient for the damper to absorb the amount of elongation in the x-axis direction as long as it can absorb 1/2 of the amount of material elongation in a single pressing operation. Even if the degree of forging is large, the damper can be absorbed in the x-axis direction. It is not always necessary to adjust the amount of stretch absorption of

In addition, when the material is formed by forging, it generally escapes in the unconstrained direction (for example, the width direction and the longitudinal direction in which it is not constrained when pressed from above and below by the mold) from the principle of constant volume. However, when a mold having a short length in the longitudinal direction is used as in the present invention, as described above, the material almost flows in the longitudinal direction at the time of molding. Therefore,
It is possible to perform forging with an upper die and a lower die as shown in FIGS. 9, 11, and 12 described later.

With this method, the primary material (FIG. 3) is molded by sequentially changing the position of the material in the longitudinal direction and changing the forging position. When molding the portion clamped by the manipulator, for example, the clamp arm 14 of the left manipulator in FIG. 1 is unclamped, and the clamped side (right side)
While manipulating the material, the manipulator 12 is moved in the longitudinal direction (on the right side in the figure), and the portion of the material to be molded (the portion that has been clamped until then) is set at the positions of the molds 55 and 56. In this state, the clamped portion is molded.

Next, a secondary material (Fig. 4) is manufactured from the primary material. At that time, molding is performed with a mold having a shape that matches the cross-sectional shape of the product in each section. In this case, the basic processing method is the same as the above-described forming of the primary material, but the difference is that the section to be formed is asymmetrical section forming as shown in FIG. In order to prevent the bending caused by this, as shown in FIG. 9, positioning and restraining are performed by the guide members 58, 58 in the width direction (z-axis direction) on the tip side of the primary material. The guide 58 and the manipulators provided at both ends of the material restrain the deformation to manufacture straight. However, the molding in this case is carried out leaving a finishing allowance of 1 to 2 mm with respect to the final product shape.

Next, the processing for molding the final product (Fig. 5) will be described. In this case, the root portion N as a reference, any position in the longitudinal direction, for example if in need of theta ₁ ° torsion in B section, the root portion N at turning motor 27, theta ₁ via the gears 28, 28 '
Rotate by °. The state of the manipulator in this state is
Shown in the figure. Further, FIG. 11 shows the forging classification (secondary material sectional shape) before forging at this time. With the secondary material rotated by θ ₁ °, the upper die 55 and the lower die 56 of the forged part are set in a state of 0 ° (horizontal state), and forging is performed in this state. The molding state is shown in FIG. This portion is in a 0 ° state, and thereby, θ ₁ ° twist forming is performed between the portion and the reference position. Since this portion is in a yield state due to the forging operation, it can be easily torsion-formed.

Here, the movements of the manipulator in the y-axis direction, the z-axis direction, and the x-axis direction are used to change the position of the material with respect to the forging position or to move the torsion center axis. According to the present embodiment, there is an effect that a long product having a cross section that arbitrarily changes and an arbitrary twist shape can be formed by the same device.

〔The invention's effect〕

According to the present invention, it is possible to use a die (divisional die) that is divided into a plurality of pieces in the longitudinal direction, the processing force for forging can be made sufficiently small, and the equipment cost of the forging device can be reduced. Further, since the sectional mold is used, the shape of the mold can be simplified, so that the man-hour for manufacturing the mold and the cost of the mold can be reduced. Regarding the die shape, in the case of the full die, even if only the twisted shape is changed, the die must be remanufactured. In the present invention, since the twist can be controlled by the rotation angle of the manipulator, the same mold can be used. Also, in the pattern,
In the case of having a twisted shape, the distribution of the working force becomes non-uniform and the life of the die becomes extremely short. However, in the present invention, since the sectional mold receives the working force uniformly, the life of the die is long. Further, according to the present invention, there is the effect that the same apparatus can be used from the basic material to the final product, and the workability can be improved.

[Brief description of drawings]

FIG. 1 is an overall front view of a molding apparatus used in carrying out the embodiment shown in FIGS. 2 to 5, and FIGS. 2 to 5 show one embodiment of the present invention. Fig. 6 is a diagram showing how the shape changes to Fig. 6, Fig. 6 is a diagram showing stress acting on a minute cube in the material to be forged, Fig. 7 is an enlarged front view of the manipulator of Fig. 6, and Fig. 8 is FIG. 7 is a side view, FIG. 9 is a side view of the forging device of FIG. 6, and FIGS.
The figure shows how the cross-section of the material changes with the forging device in Figure 9, Figures 13 to 15 show the shape of the material changed by the conventional method, and Figure 16 shows the conventional method. It is a figure showing the shaping | molding apparatus of this. 11 …… Material, 12 …… Manipulator, 13 …… Forging device,
14 …… Clamp arm, 55 …… Upper mold, 56 …… Lower mold, 58…
... Guide member.

Claims (4)

[Claims] 1. A method for forming a long product by forging, wherein the cross-sectional shape changes in the longitudinal direction and the cross-sectional shape is asymmetrical in the vertical and horizontal directions, and has a twist as a whole. Using opposing dies (55, 56) with corresponding dies shape, forging is performed for each section continuously in the longitudinal direction, and the restriction of both ends of the long product material (11) is x in the longitudinal direction. The axial direction is the forging direction, the y-axis direction is the x-axis direction, and the direction perpendicular to the y-axis direction is the z-axis direction. One end side is constrained to the y-axis direction x-axis rotation z-axis direction and the other end side is the y-axis direction. A method of forging a variable cross-section elongated article, which comprises constraining in the z-axis direction, and constraining the one end side around the x-axis by previously giving a twist angle to the one end side in a section for which forging is performed. 2. An apparatus for forming a long product by forging, the cross-sectional shape of which is changed in the longitudinal direction and which is asymmetrical in the vertical and horizontal directions, and which is twisted as a whole, into a plurality of sections divided in the longitudinal direction of the long product. A forging device (13) having an upper die (55) and a lower die (56) having corresponding die shapes and forging in each section by moving in the longitudinal direction.
And two manipulators (12) having clamp arms (14) that clamp both ends of the material (11) for a long product and restrain the movement of the material (11) in a direction perpendicular to the longitudinal direction. An apparatus for forging a variable cross section, wherein one of the clamp arms (14) can be fixed at an arbitrary rotation angle around the longitudinal axis and the other can freely rotate around the longitudinal axis. 3. The forging device (13) according to claim 2, wherein the forging device (13) is in the vicinity of the upper die (55) and the lower die (56), and is a guide member for preventing bending in the left-right direction by contacting the long product. 58) A forging device for a variable cross section having. 4. The forging of a variable cross section object according to claim 2, wherein the clamp arm (14) has a damper (22) made of an elastic material that functions in the longitudinal direction, the vertical direction and the lateral direction of the long product. apparatus.