CN1076993C - Method of fabricating shaft from metal plate - Google Patents

Abstract

The present invention forms a shaft of high precision through a first procedure for front extrusion processing by processing a metal plate 1 with pressure and a second procedure for extending a protrusion part into a shaft shape by pressing a punch on the protrusion part obtained in the first procedure and extruding in the back by aiming at vertically forming the shaft integrated with the metal plate in any positions of the metal plate.

Description

Method of forming shafts from sheet metal

The present invention relates to a shaft forming method for forming a shaft integral with a metal sheet from a sheet metal.

In recent years, when installing a shaft on a metal plate, the shaft processed in another process is fixed to the metal plate by riveting or placed on the metal plate by spot welding or the like.

Next, a conventional method of forming a shaft on a metal plate will be described.

Fig. 17 is a schematic diagram of a method of forming a shaft on a metal plate by means of riveting in the prior art. In this method, a hole is machined on the metal plate 10 on which the shaft 11 is to be installed, and then the shaft processed by other processes is fixed by riveting. Fig. 18 is a schematic diagram of a method of forming a shaft on a metal plate by spot welding in the prior art. This method fixes the shaft 13 processed through other processes to the metal plate 12 on which the shaft 13 is to be provided by spot welding.

In addition, Japanese Patent Application Laid-Open No. 6-26737 discloses a forming method for forming a shaft portion. As shown in FIG. 19, a first tool 22 is used to punch a plate 21 from one side, forming a hole on one side, and forming a hole on the other side. After the protruding portion 24 is formed, the lower surface 23a of the second tool 23 is contacted from the hole side, and the excess amount of the pressed part is moved toward the protruding portion by pressing, so that the protruding portion 24 is more protruded, and the first tool 22 is used to push again. Pressing increases the height of the protruding portion 24, thereby forming the shaft portion. Furthermore, as a method of forming a shaft-shaped object, there are known a forward extrusion method shown in FIG. 20 and a reverse extrusion method shown in FIG. 21 .

However, in the method of forming the shaft by riveting or spot welding in the above-mentioned prior art, since the shaft is fixed to the metal plate after processing the shaft in another process, there is a problem of high cost. In addition, when fixing by riveting, the riveting pressure causes deformation of the metal plate, and as a result, it is difficult to obtain the perpendicularity of the metal plate to the axis; and when spot welding, because the welding area is small, sufficient strength cannot be obtained.

Furthermore, in the method described in JP-A-6-26737, since the extrusion force of the tool always acts on the boundary between the plate and the protruding portion, it is difficult to ensure the height of the protruding portion, and it is necessary to obtain the height of the protruding portion relative to the plate. Squareness or outer diameter accuracy is also difficult, and there is also a problem of a large number of processing steps.

In addition, both the forward extrusion process and the reverse extrusion process are a method of forming a shaft-shaped object by processing a plate material, and therefore, an integral shaft protruding from a flat plate cannot be formed.

The present invention is proposed in order to solve the above-mentioned problems in the prior art, and its purpose is to provide a shaft forming method that can vertically form a shaft integrated with the metal plate at any position of the metal plate.

The method of forming a shaft made of a metal plate of the present invention includes: a first step of half-pressing or forward extrusion processing of the metal plate by press working; The second step is to press a punch into the protruding part of the plate and press the protruding part back in the direction opposite to the direction in which the punch is pressed, thereby extending the protruding part into a shaft shape.

In addition, the present invention is characterized in that several positions together form a shaft of the same height.

Another feature of the present invention is to perform sequential processing in such a manner that the direction in which the projection is extended in the second process and the direction in which the metal plate is punched in the other process are opposite to each other.

According to the above-mentioned structure, after pressing the metal plate and performing forward extrusion to form the protrusion, the protrusion is reverse-extruded with a punch or a die to form the shaft. Therefore, the shaft can be formed at any position on the metal plate. On the other hand, the shaft is formed integrally with the metal plate with the minimum number of processes, and the length accuracy, outer diameter accuracy, and perpendicularity can be fully guaranteed.

In addition, by forming shafts of the same height together at several positions, several shafts of the same height are elongated by the reverse extrusion process of the second process, so that even when the metal plate floats upward from the die surface, it is possible to eliminate the Unevenness in the amount of upward float or inclination of the metal plate.

Furthermore, since the elongation direction of the shaft in the second process is opposite to the direction in which the metal plate is punched in another process, when the metal plate is back-extruded in the sequential process, the die surface There is no gap between the sheet and the metal plate, making it easy to press in other processes.

Fig. 1 is a schematic view showing the state before the first step of the method for forming a shaft made of a metal plate according to an embodiment of the present invention.

FIG. 2 is a schematic view showing a state in which protrusions are formed in a first step.

Fig. 3 is a schematic diagram showing the relationship between a punch, a die, and a metal plate in a second step.

Fig. 4 is a schematic diagram showing a state after the second step is completed.

Fig. 5(a) is a schematic diagram showing the volume of the protrusion, and (b) is a schematic diagram showing the volume of the shaft.

Fig. 6 is a schematic diagram showing the relationship between the punching amount and the deflection rate of the SPCC material.

Fig. 7 is a schematic diagram showing the relationship between the punching amount of the punch and the deflection rate of the high-strength steel material.

Fig. 8 is a schematic view showing the relationship between the outer diameter of the metal plate protrusion and the inner diameter of the die.

Fig. 9 is a schematic diagram showing the relationship between the height of the protruding portion of the metal plate and the depth of the die.

Fig. 10 is a schematic diagram showing the dimensional relationship between the punch and the die in the first step.

FIG. 11 is a schematic diagram showing the relationship between the punch pressing amount and the height of the protruding portion in the first step.

Fig. 12 is a schematic diagram showing the dimensional relationship between the punch and the die in the second step.

Fig. 13 is a schematic diagram showing the punching amount in the second step.

Fig. 14 is a schematic view showing shaft dimensions after machining.

Fig. 15(a) is an explanatory view showing that the direction of axial extension in sequential processing is the same as the direction of press processing in another process.

Fig. 15(b) is an explanatory diagram showing that the direction of axial extension in sequential processing is opposite to the direction of press processing in another process.

Fig. 16 is a schematic view showing the machining state of the stepped shaft.

Fig. 17 is a schematic view showing a method of setting a shaft by riveting in the prior art.

Fig. 18 is a schematic diagram of a method of setting an axis by spot welding of the prior art.

Fig. 19 is a schematic view showing a conventional shaft forming method in a known example.

Fig. 20 is an explanatory diagram of forward extrusion processing.

Fig. 21 is an explanatory diagram of reverse extrusion processing.

Embodiments of the present invention are described below with reference to the drawings.

In Fig. 1, 1 is a metal plate that needs to protrude to set the shaft. 2 is a punch used for half-pressing a metal plate by press working or performing forward extrusion that moves the material in the same direction as the punch 2 moves. Reference numeral 3 denotes a die used for half-pressing or forward-extruding the metal plate 1 together with the punch 2 by press working. 4 shown in FIG. 2 is a protruding portion of the metal plate 1 obtained by half punching or positive extrusion. 5 in FIG. 3 is a punch used when pressing the material of the protruding part 4 toward the back. 6 is a punch used together with the punch 5 to press the protruding part 4 toward the back. 7 in FIG. 4 is a shaft processed integrally with the metal plate by back extrusion.

The process of processing the shaft integral with the metal plate 1 having the above configuration will be described below. First, the material forming the required volume of the shaft 7 is half-punched or positively extruded using the punch 2 and by press working. Next, the protruding portion 4 of the half-stamped or forward-extruded metal plate 1 is compressed by the punch 5 and the die 6 for back-extrusion, and the shaft 7 is processed. At this time, the metal plate 1 of FIG.

In the above-mentioned series of processes, firstly, in the forward extrusion process of the first process, as shown in Fig. 5(a) and (b), it is necessary to protrude the material forming the required volume of the shaft through forward extrusion. This forward extrusion process uses a die whose inner diameter is the same as the outer diameter of the shaft, and determines the punch diameter and press-in amount to match the height of the shaft. At this time, when the height of the shaft is low, the diameter of the punch can be made the same as the inner diameter of the die because there is less volume protruded by forward extrusion after processing. This is because the protruded volume is the same as the volume squeezed in by the punch. If the shaft is relatively high, a punch with a diameter larger than the inner diameter of the die must be selected due to the increased protruding volume.

However, the punching amount at this time cannot be the original protrusion amount. There must be movement of the material in other directions (hereinafter referred to as offset). Figure 6 shows the offset for SPCC material at t=1.2, and Figure 7 shows the offset for high-strength steel material at t=0.8. The inner diameter of the die is φ2. It can be clearly seen from Figure 6 that when the diameter of the punch is large, the offset of the material is also large. When the diameter of the punch is φ4, about half of the press-in amount is shifted to the periphery. It can also be seen that when the diameter of the punch is the same, the greater the amount of indentation, the less the deviation of the material.

Based on these data, the punch diameter and press-in amount required for shaft forming can be determined.

Next, the protruding portion 4 of the material obtained by the forward extrusion is fitted into the die 6 and the shaft 7 is formed by reverse extrusion processing by the punch 5 .

At this time, since the inner diameter of the die 6 must be the same as the outer diameter of the shaft 7, in order to make the protruding part 4 of the material fit into the die 6 easily, as shown in Figure 8, it is best to make the diameter of the protruding part 4 of the material A is smaller than the inner diameter B of the die 6 . In initial experiments, the diameter of the protrusion was 0.01 smaller than the inner diameter of the die for back extrusion. However, in this setting, since force is required to enter the die, it is not suitable for sequential processing dies. In experiments carried out thereafter, the diameter of the protrusion was made to be 0.05 mm smaller than the inner diameter of the die for reverse extrusion, and as a result, the protrusion entered the die smoothly. Therefore, when forming a shaft in a die for sequential processing, it is appropriate to set the inner diameter of the die for forward extrusion to be 0.01 mm to 0.1 mm smaller than the outer diameter of the shaft, preferably 0.05 mm smaller.

As the head at the time of this reverse extrusion, first, in order to smoothly move the material, it is necessary to make the tip of the punch into a tapered shape.

Also, in order for the sheet metal to float upward from the top of the die, the material cannot be extruded with a stripper.

Further, when the protrusion 4 of the metal plate 1 is embedded in the die 6, if there is a gap between the upper surface of the die 6 and the metal plate, since the base of the shaft will eventually form a step, so as shown in Figure 9, the depth of the die 6 It should be 0.05~0.1mm deeper than the height of the protruding part of the material.

As a specific example, for an SPCC material having a plate thickness t=1.2 of the metal plate 1, processing can be performed with a diameter of φ1.99 mm and a height of 3.4 mm.

At this time, the diameter _d2 of the punch 2 by the forward extrusion process shown in FIG. 10 is φ3.0 mm, and the inner diameter _d3 of the die 3 is φ1.94 mm. In addition, the size of each part of the material in FIG. 11 including the protruding part 4 formed as a result of the forward extrusion process is that the punching amount h is 1.0 mm, and the diameter A of the protruding part 4 is φ1.93 mm, The height h ₄ is 1.87 mm.

Further, in the reverse extrusion processing of the protrusion 4, as shown in FIG. 12, the diameter _d5 of the punch 5 is φ1.4mm, the inner diameter _d6 of the die 6 is φ1.99mm, and the depth _h6 of the die 6 is 1.90mm. In addition, as shown in FIG. 13, the pushing amount _h5 of the punch 5 was 1.65 mm.

The dimensions of each part of the shaft 7 shown in FIG. 14 obtained from the above results are that the plate thickness t is 1.2 mm, the height h ₇ is 3.367 to 3.432 mm, and the diameter d ₇ is φ1.983 to 1.992 mm. The errors of height and diameter are 0.07mm and 0.01mm respectively. In addition, the skew of the shaft tip is 0.00 to 0.05 mm.

In addition, the key to making the height of the shaft higher is to protrude most of the material and thin the side wall of the shaft through positive extrusion. The results of confirmation of this altitude limit are shown below.

Use SPCC material with t=1.2mm, and use a positive extrusion punch with a diameter of φ4mm. When a punch with a diameter of φ5mm is used, the amount of displacement of the material increases, and the base of the protruding part expands the material. In addition, when the side wall of the shaft is 0.1 mm, the test is carried out. Since the base of the shaft is bent due to insufficient strength, the side wall should be made 0.2 mm. As a result, the height of the shaft became 5.95 mm.

From the above examples, the following matters should be grasped.

That is to say, with regard to the skew of the shaft, in the following experiment, in order to form a shaft of φ2mm on a flat plate of 40mm×40mm, although there is no large skew, but in the case of a large material, due to the material floating during back extrusion It will cause upward jump (jump ね上ガリ), so the skew of the axis should be considered. Therefore, the shaft should be arranged in several positions to make the material bounce upward in a well-balanced manner.

In addition, in the back-extrusion step, the material jumps up during back-extrusion, but the amount of jumping up varies depending on the height of the shaft. Therefore, in the same process of back extrusion, only shafts of the same height can be formed. Again, no other processing (stamping, bending, etc.) can be done in this process, and preferably there is no control that prevents the material from jumping upwards.

Furthermore, when the reverse extrusion process is performed in the die for sequential processing, the direction of the axis can be restricted. As shown in Fig. 15(a), when forming a downward shaft 30, since the material 31 jumps upward at the upper part, there is a gap between the die surface 32 and the material 31, and when processing such as punching is performed in another process 33, The deflection will eventually occur on the material 31. On the contrary, when the upward shaft 34 is formed, as shown in FIG. , Pressing and the like can be easily performed in another process 35 .

In addition, by performing subsequent processing on the shaft 7 formed in this embodiment, a shaft with steps 40 as shown in FIG. 16 can be formed.

In the present invention as described above, after pressing the metal plate and performing forward extrusion to form the protrusion, the protrusion is reverse-extruded with a punch or a die to form a shaft. At any position on the plate, a shaft that is integrated with the metal plate is formed with the least number of processes, and the length accuracy, outer diameter accuracy, and perpendicularity can be fully guaranteed.

In addition, by forming shafts of the same height at several positions and extending several shafts of the same height by means of reverse extrusion processing in the second process, upward floating can be eliminated even when the metal plate floats upward from the die surface The unevenness of the amount and the inclination of the metal plate.

Furthermore, since in the second process, the elongation direction of the shaft is opposite to the direction of stamping on the metal plate in the other process, when the metal plate is back-extruded during the sequential process, the die There is no gap between the surface and the metal plate, making it easy to perform press processing in other processes.

Claims (6)

1, (revise back) is a kind of makes the manufacturing process of axle by metallic plate, comprising: first operation of metallic plate being carried out semi-stamping or forward extrusion processing by pressure processing; Resulting by aforementioned first operation, remain on the protuberance of the aforementioned metal plate in the punch die, with with aforementioned first operation in the semi-stamping of pressure processing or the identical direction of forward extrusion machine direction be pressed into drift, aforementioned protuberance is carried out backward extrusion, make protuberance extend second operation of a shape thus.

2, according to claim 1ly make the manufacturing process of axle, it is characterized in that, in second operation, be used to keep the punch die internal diameter of protuberance to set the big 0.01mm～0.1mm of external diameter for than aforementioned protuberance by metallic plate.

3, according to claim 1ly make the manufacturing process of axle, it is characterized in that, in second operation, be used to keep the degree of depth of the punch die of protuberance to set for than the dark 0.05mm～0.1mm of the height of aforementioned protuberance by metallic plate.

4, according to claim 1 by metallic plate make the axle manufacturing process, it is characterized in that in second operation, the drift that utilizes front end to make taper carries out backward extrusion to protuberance.

5, according to claim 1 by metallic plate make the axle manufacturing process, it is characterized in that, form together in several positions sustained height the axle.

6, according to claim 1ly make the manufacturing process of axle, it is characterized in that, in second operation, so that protuberance elongation forms the direction of axle and in another operation metallic plate carried out the reverse each other mode of die-cut direction and carry out order and process by metallic plate.

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