JPS6245793Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention relates to a forging die that plastically deforms a workpiece housed inside the die by applying pressure with a punch inserted into the die. For example, it can be used in so-called backward perforation extrusion processing.

Prior Art For example, when processing a workpiece 1 having the shape shown in FIG. 1 into a product 2 having the shape shown in FIG. There are cases where it is done. An example of this will be explained with reference to FIGS. 3 and 4.
The tip of the punch 3 is formed to have the same outer shape as the inner surface of the hole 5 to be formed in the product 2, and the inner surface of the lower part of the die 4 is formed to be the same as the outer shape of the product 2 to be obtained. There is. In order to perform the backward drilling and extrusion processing, first the workpiece 1 is
is housed inside the die 4 as expected, and then the punch 3 is inserted into the die 4 and pressurizes the workpiece 1 with its tip, resulting in plastic deformation of the workpiece 1 to form the product 2. .

By the way, since the hole 5 needs to be formed at the center of the rear part of the product 2, the punch 3 is guided by the inner peripheral surface of the die 4 so that both are located on the same axis. That is, the inner peripheral surface of the hollow part of the die 4 is used as the guide surface 6, and the outer peripheral surface of the punch 3 is used as the guided surface 7, and the punch 3 is used as the die 4.
It is held on the same axis as the However, when the workpiece 1 is pressurized by the punch 3, a compressive force acts on the punch 3, so the punch 3 expands elastically in the radial direction, and the workpiece 1 is pushed and expanded by the punch 3. As a result, the inner diameter of the die 4 expands slightly, but the amount of elastic expansion of the punch 3 in the radial direction is larger than the amount of expansion of the inner diameter of the die 4, and in the case of hot forging, the elasticity of the punch 3 increases. Thermal expansion is added to the expansion. Therefore, when the gap between the guide surface 6 and the guided surface 7 is reduced in order to accurately hold the punch 3 on the same axis as the die 4, the workpiece 1 is pressurized by the punch 3. At this time, the punch 3 comes into contact with the inner circumferential surface of the die 4, and as a result, the punch 3 and the die 4 cause so-called seizure, and the risk of seizure occurrence increases especially when mass production is performed at a faster machining speed. do. Conventionally, in order to eliminate such inconvenience, the guide surface 6
The gap between the guide surface 7 and the guide surface 7 is set large in consideration of the amount of expansion of the punch 3 in the radial direction, which increases the so-called lateral vibration of the punch 3 before applying pressure, which causes the product 2 There was a problem that the concentricity between the hole 5 and the outer peripheral surface deteriorated.

Purpose of the invention This invention was made in view of the above circumstances, and aims to maintain the punch accurately on the same axis as the die, thereby ensuring concentricity between the inner part processed by the punch and the outer part processed by the die. The purpose is to provide a forging die that can produce products with high quality.

Structure and operation of the device This device continuously forms a guide portion and a relief portion recessed outside the guide portion in the radial direction on the inner circumferential surface of the hollow portion of the die, Furthermore, on the outer peripheral surface of the punch inserted into the hollow part of the die, a guided part and a recessed part recessed toward the center in the radial direction than the guided part are continuously formed in the axial direction, and the die is further The relative positions of the guide portion and relief portion of the punch and the guided portion and recessed portion of the punch are such that when the punch pressurizes the workpiece and expands in the radial direction, the guided portion of the punch is aligned with the axis of the die relief portion. The recessed part of the punch is set to match the guide part of the die in the axial direction, and the gap in the radial direction between the guided part and the relief part and the recessed part and the guide part when no pressure is applied are set. The gap in the radial direction is set to be slightly larger than the amount of elastic expansion of the punch in the radial direction. Therefore, in this idea,
Before the punch applies pressure to the workpiece, the guide part and the guided part are aligned, so the action of both holds the punch on the same axis with respect to the die, and the punch also presses the workpiece. When an object is pressurized, the guide part and the recessed part match, and the escape part and the guided part match, so even if the punch elastically expands in the radial direction, the punch and die do not move in the radial direction. No face-to-face contact.

Embodiment An embodiment of this invention will be described below with reference to FIGS. 5 to 7. FIG. 5 is a sectional view showing a forging die 10 for processing the workpiece 1 having the shape shown in FIG. 1 into the product 2 having the shape shown in FIG. It is comprised of a punch 11 that pressurizes the workpiece 1 to plastically deform it, and a die 12 that accommodates the workpiece 1 and into which the punch 11 is inserted. In other words, the tip of the punch 11 is the product 2.
The hole 5 is formed in the same shape as the inner surface of the hole 5 to be formed in the rear part of the punch 11, and guided portions 13 and recesses 14 are formed alternately and continuously in the axial direction on the outer peripheral surface of the punch 11. There is. Guided part 13
is for holding the punch 11 on the same axis with respect to the die 12 in cooperation with a guide portion 15 of the die 12, which will be described later, and is set to a predetermined length in the axial direction. Further, the recess 14 is formed by the punch 11.
It is provided in order to avoid interference with the guide portion 15 of the die 12, and is retracted toward the center in the radial direction than the guided portion 13, and is set to a predetermined length in the axial direction. There is.

On the other hand, the die 12 has a hollow portion 16 for accommodating the workpiece 1 and inserting the punch 11, and the inner surface shape at the lower end of the hollow portion 16 is the same as the outer surface shape of the product 2 to be obtained. is formed. Further, on the inner circumferential surface of the hollow portion 16, guide portions 15 and relief portions 17 are formed consecutively and alternately in the axial direction. The guide portion 15 is for guiding the punch 11 in the vertical direction while holding it on the same axis as the die 12, and has a predetermined length in the axial direction. Therefore, the dimensional difference between the inner diameter D of the guide part 15 and the outer diameter d of the guided part 13, that is, the difference between the guide part 15 and the guided part 13
The gap is set to the minimum dimension within the range in which the punch 11 can move up and down. The relief portion 17 is provided to prevent the guided portion 13 of the punch 11 from interfering with the die 12, and is retracted outward from the guide portion 15 in the radial direction and in the axial direction. It is set to a predetermined length.

Here, the relative positions and dimensional differences or gaps between the guided portion 13 and recess 14 and the guide portion 15 and relief portion 17 will be explained.
2, the guided part 13 and the guide part 15 coincide in the axial direction, and the recessed part 14 and the relief part 17 coincide in the axial direction, from just before contacting the workpiece 1 in the hollow part 16 of 2 until it slightly bites into the workpiece 1. When the punch 11 further pressurizes the workpiece 1 and expands elastically in the radial direction, that is, at approximately the lower limit position of the punch 11, the guided portion 1
3 corresponds to the relief part 17, and the recess 14 corresponds to the guide part 15 in the axial direction. Further, the gap between the guided part 13 and the guide part 15 is as described above, and in contrast, the gap between the guided part 13 and the guided part 15 is The gap between the groove 17 and the guide section 15 is set to be larger than the amount of elastic expansion of the punch 11 when the workpiece 1 is pressurized by the punch 11.

The workpiece 1 is made into a second material by the forging die 10 described above.
In order to process the product 2 having the shape shown in the figure, the workpiece 1 is placed in the hollow part 16 of the die 12 as shown in FIG.
Then, as shown in FIG. 6, the punch 11 is inserted into the hollow part 16 of the die 12 and the workpiece 1 is pressurized with its tip. As a result, the workpiece 1 is plastically deformed, and the outer surface has a hollow part 16.
The inside has the same shape as the inner surface, and a hole 5 is punched in the center of the rear part using the tip of the punch 11.

7A, B, and C are partial sectional views showing the situation from the start to the end of pressurizing the workpiece 1 by the punch 11, in which the tip of the punch 11 is attached to the hollow part 1.
At the start of pressurization when the workpiece 1 in contact with the workpiece 1 is started, the guided portion 13 and the guide portion 15 are aligned as shown in FIG. However, the punch 11 has a minimum dimension that allows it to move up and down, and therefore the punch 11 is held precisely on the same axis relative to the die 12 by the cooperative action of the guided portion 13 and the guide portion 15. has been done. When the punch 11 is lowered from this state, the punch 11 plastically deforms the rear part of the workpiece 1 and bites into it. In that case, the guided portion 13 of the punch 11 comes off from the guide portion 15 of the die 12 as shown in FIG. 7B, and the punch 11
The gap between the die 12 and the die 12 widens, and as a result, the punch 11 is not actively held and guided by the guide portion 15 of the die 12, but the punch 11 is previously aligned precisely on the same axis as the die 12. Since the punch 11 is held in place while biting into the workpiece 1, even if the punch 11 is not actively held and guided by the guide portion 15, it will not oscillate laterally and become misaligned. When the punch 11 is further lowered, the punch 11 is lowered while being aligned with the die 12 on the same axis, and at the same time presses the workpiece 1 even more strongly to plastically deform it. That state is the seventh
In the state shown in Figure C, when the punch 11 has descended almost to the lower limit as shown here, the compressive force acting on the punch 11 is almost at its maximum, and as a result, the punch 11 expands elastically in the radial direction (by the expansion amount). (shown with crosshatching in Figure 7C)
However, the guided portion 13 of the punch 11 is aligned with the relief portion 17 of the die 12 in the axial direction, the recessed portion 14 is aligned with the guide portion 15, and the gap between these is set to be larger than the amount of elastic expansion of the punch 11. Therefore, the outer circumferential surface of the punch 11 and the inner circumferential surface of the hollow portion 16 of the die 12 do not come into contact with each other.
Therefore, even if the punch 11 is moved up and down as it is, there is no risk that the punch 11 will seize against the die 12.

In the above embodiment, each of the guided portion 13, the recessed portion 14, the guide portion 15, and the escape portion 17 are formed at two locations as shown in the figure, but each of these portions may be provided at one location. Alternatively, it may be provided at three or more locations.

Effects of the invention As is clear from the above explanation, according to the forging die of this invention, immediately before pressurizing the workpiece with the punch, the guided part formed on the punch and the guide part formed on the die are used. The punch is held on the same axis as the die, and after the punch plastically deforms the workpiece and bites into it, the guided part of the punch coincides with the escape part of the die, and the concave part aligns with the guide part. They match, and the gap between them is set to be larger than the amount of elastic expansion of the punch in the radial direction, so the outer circumferential surface of the punch does not come into contact with the inner circumferential surface of the die. Therefore, in this design, the punch is held exactly on the same axis as the die until the punch bites into the workpiece, and when the punch expands elastically in the radial direction, the gap between the two is Since the punch and the die are made large so that they do not come into contact with each other, there is no risk of seizure between the punch and the die, and a forging die that can forge a product with high concentricity of the inner and outer diameters can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a front view showing an example of a workpiece, FIG. 2 is a sectional view showing a product obtained by forging the workpiece, and FIG. 3 is a schematic sectional view showing a conventional forging die. Fig. 4 is a schematic cross-sectional view showing the state when pressurization is completed by a conventional forging die, Fig. 5 is a schematic cross-sectional view showing an embodiment of this invention, and Fig. 6 is a schematic cross-sectional view showing the state when pressurization is completed by a conventional forging die. A schematic cross-sectional view showing the state when pressing is completed, and FIGS. 7A, B, and C are partial cross-sectional views showing the process from the start of pressing the workpiece by the punch to the completion of pressing. 1...Workpiece, 2...Product, 10...Forging die, 11
...Punch, 12...Dice, 13...Guided part, 1
4... recessed part, 15... guide part, 17... escape part.

Claims (1)

[Scope of utility model registration request] In a forging die that pressurizes and plastically deforms the workpiece by inserting a punch into a die containing a workpiece, the die includes a guide portion and a guide portion on the inner peripheral surface of the die. A relief portion is formed continuously in the axial direction, and a relief portion is formed on the outer peripheral surface of the punch, and a relief portion is formed on the outer peripheral surface of the punch, and a relief portion is formed on the outer peripheral surface of the punch. The inserted recess is formed continuously in the axial direction, and the relative positions of the guide part and relief part of the further die and the guided part and recess of the punch are such that the punch pressurizes the workpiece and elastically expands. At this time, the guided part of the punch is set so as to match the relief part of the die in the axial direction, and the recessed part of the punch is set to match the guide part of the die in the axial direction,
In addition, when no pressure is applied, the radial gap between the guided part and the escape part and the radial gap between the recessed part and the guide part are set to be larger than the amount of elastic expansion of the punch in the radial direction. A forging die characterized by: