JPH03261Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a molding die for molding a hollow stepped molded product.

(Prior Art) Conventionally, as this type of forging mold, for example, as shown in FIG. 3, a die 3 having a stepped forming hole 2 provided on a hard plate 1, 4, which is fixedly supported by the upper die holder 4 via a punch receiver 5 and inserted into the forming hole 2 of the die 3, as shown in FIG. A mandrel 6 that can be fitted into a hollow hole b of a hollow processed product a, and a punch 7 that is fitted to the outer periphery of the mandrel 6 and supported by the upper die holder 4 via a punch receiver 5, By lowering the upper mold holder 4, the mandrel 6 and punch 7 are lowered by a predetermined stroke into the forming hole 2 of the die 3, and a hollow stepped molded product c (see Fig. 5) is cold-formed. Those who did so are known. In FIG. 3, reference numeral 8 denotes a knock-out member that is slidably inserted into the lower side of the forming hole 2 of the die 3. The upper end of the knock-out rod 9 which moves up and down facing the mold is connected to the upper end of the knock-out rod 9, and after the upper die holder 4 rises to collect the molded product c, the knock-out member 8 is moved upward by the knock-out rod 9. The molded product c in the molding hole 2 is pushed upward through the molding hole 2.

By the way, when forming a hollow stepped molded product c from a hollow processed product a using such a forging mold, the inner diameter, outer diameter, etc. of the hollow processed product a are set appropriately in advance, and the upper mold is When the hollow stepped molded product c is molded by lowering the holder 4, the surface pressure of the molded product c on the molding hole 2 is made larger than the surface pressure on the mandrel 6, and thereby the upper die holder The molded product c remains in the molded hole 2 when the molded part 4 is raised.

(Problem to be solved by the invention) However, in the above-mentioned conventional forging mold, if there is a dimensional error in the hollow workpiece a, the surface pressure of the molded product c against the mandrel 6 is greater than the pressure applied to the forming hole 2. As the upper mold holder 4 rose, the molded product c sometimes rose while biting into the mandrel 6. In this case, it is necessary to perform the extremely troublesome work of removing the molded product c from the mandrel 6 using a hammer or the like, resulting in a problem that work efficiency is significantly reduced.

Therefore, in order to solve this problem, it is considered to form a groove on the inner peripheral surface of the forming hole of the die, and to forcibly leave the molded product c in the forming hole 2 using the groove. It will be done. However, in this case, when the molded product c is pushed upward from the molding hole 2 by the upward movement of the knockout rod 9 after the upper mold holder has been raised, the portion of the molded product c corresponding to the groove is cut. There is a problem in that the particles are removed and remain in the molded hole 2.

On the other hand, as shown in Japanese Unexamined Patent Publication No. 56-59555, there is a die that is divided into a lower die and an upper die that moves up and down from the part where the groove is formed; There is a problem in that a drive mechanism is required to move the device, which complicates the device.

In view of these points, the purpose of the present invention is to allow the mandrel to slide against the molded product in advance during the forging of a hollow stepped molded product by lowering the upper die holder, and to The object of the present invention is to provide a forging mold that can reliably prevent chamfering by reducing the surface pressure of the steel.

(Means for Solving the Problem) In order to achieve the above object, the solution means of the present invention includes a die having a stepped forming hole, an upper die holder that moves up and down opposite to the die, and an upper mold holder that moves up and down opposite the die. a mandrel supported by a mold holder and fitable into a hollow hole of a hollow processed product inserted into a molding hole of the die; and a punch supported by the upper mold holder in a state fitted to the outer periphery of the mandrel. In the forging mold, the mandrel and the punch are lowered by a predetermined stroke into the forming hole of the die by lowering the upper mold holder to form a hollow stepped molded product. The holder is supported so as to be movable in the vertical direction and is provided so as to be movable relative to the punch, and is placed in the forming hole of the die and comes into contact with the tip surface of the mandrel in the latter half of the forming stroke of the punch to restrict its movement. A knock-out member is provided.

(Function) With the above configuration, in the forging mold of the present invention, when the upper mold holder is lowered, the mandrel and the punch stroke downward in the forming hole of the die to form a hollow stepped molded product. In the latter half of the forming stroke, the tip end surface of the mandrel comes into contact with the knockout member and its movement is restricted, and the mandrel
As the punch descends, it slides relative to the punch and the molded product pressed by it. Therefore, the surface pressure of the molded product on the mandrel is reduced as much as possible, and the molded product is ensured to remain in the molding hole of the die when the upper mold holder is raised.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

1 and 2 show a forging mold A according to an embodiment of the present invention, and this forging mold A has a hollow stepped product as shown in FIG. This is for making molded product c. Incidentally, since the basic structure of the forging mold A has already been explained in FIG. 2, the same members are given the same reference numerals and detailed explanation thereof will be omitted. That is, in the forging mold A, the upper die holder 4 is lowered to lower the mandrel 6 and the punch 7 into the forming hole 2 of the die 3 by a predetermined stroke to form a hollow stepped molded product c. It is configured.

As a feature of the present invention, the punch receiver 5, which is interposed between the mandrel 6 and the punch 7 and the upper die holder 4 in order to support them, has a hollow portion 10 corresponding to the mandrel 6. The proximal end of the mandrel 6 is slidably inserted into the hollow portion 10 in a manner that prevents it from coming off.
Therefore, the mandrel 6 is supported to be movable in the vertical direction with respect to the upper mold holder 4 via the punch receiver 5, and the mandrel 6 and punch 7 are connected to the upper end surface of the mandrel 6 and the upper surface of the hollow part 10. It is provided to be relatively movable in the vertical direction by the gap between them. Further, the knockout member 8 fitted into the lower side of the molding hole 2 of the die 3 has a protrusion 11 that protrudes upward.
is formed. The outer diameter of the protrusion 11 is set to be slightly smaller than the outer diameter of the mandrel 6, and its protrusion height is set appropriately, so that it can be used in the latter half of the forming stroke of the punch 7 (the stopper formed on the punch receiver 5). The portion 12 is approximately 3 to 4 mm on the top surface of the die 3.
mm), the protruding portion 11 comes into contact with the tip end surface (lower end surface) of the mandrel 6 to restrict its movement.

Next, to explain the function and effect of the above-mentioned forging mold A, when forging a hollow stepped molded product c from a hollow processed product a using the forging mold A, first, the hollow processing The hollow processed product a is inserted into the forming hole 2 of the die 3 with the hollow hole b of the product a facing up and down.

Thereafter, when the upper mold holder 4 is lowered and the mandrel 6 and punch 7 are stroked downward into the forming hole 2 of the die 3, the mandrel 6 is inserted into the hollow hole b of the hollow workpiece a, and this state is reached. When the punch 7 presses the hollow workpiece a from above, a hollow stepped molded workpiece c is formed corresponding to the shape surrounded by the inner peripheral surface of the formed hole 2, the outer peripheral surface of the mandrel 6, and the lower end surface of the punch 7. is molded.

At this time, in the latter half of the forming stroke of the punch 7, as shown in FIG.
The protruding portion 11 formed in the above contacts the tip of the mandrel 6 and restricts the downward stroke of the mandrel 6, so that the punch 7 after the point of contact comes into contact with the tip of the mandrel 6.
In the forming stroke, mandrel 6 and punch 7
and the molded product c pressed by the punch 7 (in particular,
(the large diameter portion) becomes relatively shifted (see a comparison between FIG. 1 and FIG. 2). That is, the punch 7 and the molded product c pressed by it descend between the inner peripheral surface of the molding hole 2 of the die and the outer peripheral surface of the mandrel 6, both of which are in a fixed state. Therefore, the surface pressure of the molded product c on the mandrel 6 is significantly reduced compared to the conventional case where the mandrel 6 descends integrally with the punch 7 and the molded product c pressed by the punch 7. . The outer diameter of the mandrel 6 is the molding hole 7 of the die 3.
, the surface pressure of the molded product c on the mandrel 6 is significantly reduced compared to the surface pressure of the molded product c on the inner peripheral surface of the molded hole 2. In addition, when the molded article c is molded, a space 15 is created between the proximal end of the mandrel 6 and the retaining part side of the hollow part 10, as shown in FIG.

When the upper mold holder 4 is raised after forming the molded product c, the punch receiver 5 and the punch 7 are moved into the space 1 while the mandrel 6 remains stationary.
It rises by the amount of 5, and then all three rise as one. In response to this movement, die 3
The molded product c left in the molding hole 2 is first separated from contact with the pressing surface (lower end surface) of the punch 7, and then separated from contact with the mandrel 6.

Therefore, in this way, when molding the molded product c, the surface pressure of the molded product c on the mandrel 6 is significantly reduced compared to the surface pressure on the inner peripheral surface of the molding hole 2 of the molded product c, and Since the contact between the molded product c and the upper mold holder 4 side is separated in two stages when the upper mold holder 4 is raised after forging, the molded product c is removed from the upper mold holder 4 side when the upper holder 4 is raised. It does not bite into the mandrel 6 etc. and move upward, and the formed hole 2
It remains firmly attached to the inner circumferential surface. As a result, the extremely troublesome work of removing the molded product c from the mandrel 6 is not necessary, and the work can be done quickly and efficiently.

Thereafter, the molded product c is pushed upward from the molding hole 2 through the knockout member 8 by the upward movement of the knockout rod 9, and is recovered. At this time, the molded product c itself is not of a special shape such that it cannot be taken out from the molding hole 2 unless a part of it is cut, and it can be easily removed without leaving any cutting powder in the molding hole 2. Since the cutting powder can be taken out, not only is there no need for a special device for removing the cutting powder, but the device (for example, a piston device, etc.) that moves the knock out rod 9 up and down can be made smaller, making it easier to carry out the work. This is very advantageous in terms of promoting

(Effects of the invention) As described above, according to the forging mold of the invention, the movement of the mandrel is regulated by the knockout member in the latter half of the forming stroke of the punch, and the mandrel, the punch, and the molded product pressed by it are regulated. By deviating from each other relatively, the surface pressure of the molded product on the mandrel can be significantly reduced as much as possible, and at the same time, contact between the molded product and the upper mold holder side is minimized when the upper mold holder is raised. Since the separation is carried out in stages, it is possible to reliably prevent the phenomenon in which the molded product bites into the mandrel and rises when the upper die holder rises due to dimensional errors in the workpiece, and thus the forging work is improved. Efficiency can be improved. Moreover,
When taking out the molded product remaining in the molding hole of the die after the upper die holder is raised, there is no problem such as part of the molded product being cut off, which is very advantageous in terms of practical implementation.

[Brief explanation of the drawing]

Figures 1 and 2 show the overall configuration of a forging mold according to an embodiment of the present invention, with Figure 1 being a longitudinal cross-sectional side view of the punch at the latter stage of the forming stroke, and Figure 2 being a side view of the punch at the latter stage of the forming stroke. FIG. 3 is a longitudinal side view at the end of a forming stroke. FIG. 3 is a longitudinal sectional side view of a conventional forging mold, FIG. 4 is a perspective view of a hollow processed product, and FIG. 5 is a perspective view of a hollow stepped molded product. 2... Molding hole, 3... Die, 4... Upper die holder, 6... Mandrel, 7... Punch, 8...
Knock-out member, a: hollow processed product, b: hollow hole, c: stepped molded product.

Claims (1)

[Scope of utility model registration request] A die having a stepped forming hole, an upper die holder that moves up and down in opposition to the die, and a hollow hole of a hollow processed product supported by the upper die holder and inserted into the forming hole of the die. A mandrel that can be inserted into the mandrel, and a punch supported by the upper mold holder in a state that is fitted to the outer periphery of the mandrel, and when the upper mold holder is lowered, the mandrel and punch are inserted into the forming hole of the die. In the forging mold for molding a hollow stepped molded product by lowering the mandrel by a predetermined stroke, the mandrel is supported to be movable in the vertical direction with respect to the upper die holder and is provided to be movable relative to the punch. The forging mold is further characterized in that a knock-out member is provided in the forming hole of the die to abut on the tip end face of the mandrel in the latter half of the forming stroke of the punch and restrict the movement thereof.