JPH0237923A - Punch for piercing - Google Patents

Abstract

PURPOSE:To smoothly separate a material to be worked from a die by forming a piercing land in the tip of a stem, providing a carrying land having a little larger diameter on the stem part being near a shank, allowing the carrying land to go into a hole of the material to be worked and drawing up the material to be worked from the die. CONSTITUTION:On the top part of a stem 1b, a piercing land 4a for piercing an object to be worked W is formed, and a carrying land 1e is provided through a diameter reducing part 1d. The diameter of the carrying land 1e is fitted and inserted with moderate frictional force into the inside surface of a material to be worked which has been punched by the piercing land 1a, and a diameter and thickness for obtaining sufficient frictional force which can draw up the material to be worked are set. The stem 1b is formed to the diameter of the same size as that of the diameter reducing part 1d and prevents friction against the inside surface of the hole. A continuous part of each land forms a gentle curved surface (r) is formed in order to avoid a partial high load. Burnishing can also be executed by using a burnishing land instead of the carrying land. In such a way, a work is carried stably and double hitting of the work caused by a carrying miss is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a piercing punch used in a piercing press device.

(Prior art) Conventionally, in press working to pierce workpieces such as metal products, as shown in Japanese Utility Model Application Publication No. 80-181220, the workpieces are superimposed and positioned on a die surface, and then pierced. Lower the piercing punch and pierce the workpiece using the piercing land formed at the tip of the piercing punch and the opening of the die. The pierced workpiece is supported by the friction between the piercing land and the hole in the workpiece, and rises together with the rise of the punch.
It is detached from the piercing punch by a stripper, and is blown away from the die position of the press device by high-pressure air or the like and stored in an external workpiece accommodating section such as a stocker.

As shown in FIG. 9, the piercing punch has a piercing land 1a formed at its tip for piercing the workpiece. The land 1a for piercing is formed integrally with the shank 1c via the stem 1b. The shank 1c is configured to be attached to a ram (not shown) by a punch holder (not shown).

(Issue RIi to be solved by the invention) However, in the piercing punch configured as described above, the area of contact between the stem and the hole drilled in the workpiece is reduced to reduce the punching force. In addition, it is formed to have a smaller diameter than the land for piercing in order to prevent the generation of frictional heat and prevent burn-in. Therefore, the punch can be used for a long time, and there are effects such as improved wear resistance. On the other hand, the hole in the workpiece drilled by the piercing land provided at the tip of the punch has a diameter larger than the diameter of the stem, making it impossible to obtain sufficient frictional force between the hole in the workpiece and the piercing punch. 1. After piercing, even if the piercing punch rises toward the top dead center, the workpiece cannot follow the rise of the piercing punch, that is, the movement toward the top dead center, and falls, and is then fed. Not only is there a problem called "double punching" where piercing is performed again along with the workpiece, resulting in breakage of the punch and a decrease in work efficiency, but it is also necessary to automate the press lit. Reliable transport of workpieces from above is also required.

Therefore, in view of the above-mentioned points, the present application prevents the workpiece from prematurely separating from the piercing punch when the piercing punch is raised during piercing, and enables smooth and reliable conveyance of the workpiece. The purpose is to provide a punch for piercing.

(Means for Solving the Problems) The present invention forms a piercing land for piercing a workpiece at the tip of the stem of a punch, and a stem closer to the shank than the piercing land via a reduced diameter portion. A conveying land having a diameter slightly larger than the piercing land is provided at the portion, and the conveying land enters the hole of the workpiece drilled by the piercing land as the piercing operation is performed, It is characterized by contacting the inner surface of the hole with sufficient frictional force to pull up the workpiece after piercing from the die.

(Function) Following the operation of piercing the workpiece with the piercing land, the conveyance land provided at the stem portion of the piercing land via the reduced diameter part transfers the pierced workpiece. It enters the inner surface of the hole, and as the punch moves upward, it acts to separate the workpiece from the die due to the frictional force between the outer circumferential surface of the conveying land and the inner surface of the hole of the workpiece.

(Example) Examples of the piercing punch of the present invention will be described below with reference to FIGS. 1 to 8. Note that in FIGS. 1 to 8, parts corresponding to those in FIG. 9 are given the same reference numerals for convenience of explanation. In this embodiment, the piercing punch 1 shown in FIG.
is formed into a flange shape. A stem 1b extends from the shank 1c. Top of stem 1b (nose)
A land 1a for piercing is formed for making a hole in a workpiece (not shown), and a land 1e for conveyance is provided in the vicinity of the land 1a for piercing via a reduced diameter portion 1d. . Stem lb, diameter reduction part 1 for piercing process
d, the conveyance land 1e is shown in detail in the second section A of FIG.
It is made as shown in the figure, and the dimensions in this example are the diameter of the piercing land 1a: 15s+s, the thickness: 2 It is determined by various conditions such as press accuracy. The reduced diameter portion 1d has the same size as the diameter of the stem 1b, which will be described later, and is smaller in diameter than the piercing land, with a diameter of 14.5 mm, so that it is smaller than the hole in the workpiece punched by the piercing land. The contact area with the inner surface is reduced, reducing punching force and preventing the generation of frictional heat. Transport land! e is the reduced diameter part 1
It is provided at the end on the side closer to the shank 1c of d, and is formed to have a diameter of 15.05 mm, which is slightly larger than the diameter of the piercing land 1a, and a thickness of 1-1. The diameter of the conveyance land 1e is such that it is fitted into the inner surface of the hole of the workpiece punched by the piercing land 1a with a moderate frictional force, and the diameter of the conveyance land 1e is determined by the friction between the outer peripheral surface of the conveyance land and the inner surface of the hole of the workpiece. , the diameter and thickness are set to obtain sufficient frictional force to pull up the workpiece. The stem 1b has the same diameter as the reduced diameter part 1d, and is smaller than the diameters of the piercing land 1a and the conveyance land 1e, and has a contact area with the inner surface of the hole of the workpiece like the diameter tightening part. This reduces the punching force and prevents the generation of frictional heat.

Note that the land 1a1 for piercing has a reduced diameter portion 1d.

The continuous portion of the conveying land 1e and the stem 1b is formed with a gentle curved surface r in order to avoid local high loads.

Next, the operation of the piercing punch of the present invention will be explained based on FIGS. 3 to 8.

A flange-shaped shank 1c formed at the base of the piercing punch 1 is brought into contact with the ram 2, and fixed to the ram 2 by the punch holder 3 and bolts 3a13a. On the other hand, a die 4 provided on the lower die facing the piercing punch 1 has a recess 4 into which a workpiece (hereinafter referred to as work W) is positioned and fitted.
a is formed, and the recess 4a is provided with an opening 4b,
A discharge hole 4c through which scrap punched from the workpiece W is discharged is in communication. The die 4 is further supported by a stripper 5 having a hole 5a through which the top of the piercing punch 1 passes, by a spring Sz S+ bolt 5b15b. The workpiece W is fitted into the recess 4a of the die 4, and the ram 2 is moved downward in the six directions of the arrows, that is, toward the bottom dead center, and the piercing punch 1 is lowered and the tip of the piercing punch 1 is moved downward. Land for piercing 1 installed in
A hole is drilled into the workpiece W by a.

The piercing punch 1 pushes down the stripper 5 against the tension of the spring BsS by the contact between the taper part 1f of the punch l and the hole 6a of the stripper 5 by the ram 2, and the piercing land 1a of the workpiece W pierces the hole. hole W
It descends to the position shown in FIG. 4 where the inner surface of the hole a engages with the outer periphery of the conveyance land 1e provided on the piercing punch 1, and then stops.

Next, the ram 2 is raised in the direction of arrow B, that is, toward the top dead center. Then, since the diameter of the transport land 1e is slightly larger than the diameter of the piercing land 1a, the outer diameter of the transport land 1e is slightly larger than the diameter of the hole Wa drilled in the workpiece W. , an appropriate frictional force is obtained, and the workpiece W is raised as the piercing punch 1 is raised. The piercing punch 1 is raised to the position shown in FIG.
The stripper S comes into contact with the stripper S, the upward movement of the stripper 5 is stopped, and the conveyance land 1 of the piercing punch 1 is
The workpiece W engaged with e rises to come into contact with the stripper 6.

After the stripper 5 stops, the ram 2 further rises, and the sixth
As shown in the figure, the conveyance land 1e is pulled out from the hole Wa of the workpiece W, and the workpiece W is separated from the conveyance land 1e and falls.
The stocker (not shown) is blown away by the air ejected from the air ejection nozzle 8 controlled by the limit switch.
It is transported and stored.

FIG. 7 shows the top of a piercing punch which is another embodiment of the present invention. 1g is provided. The varnish processing land 1g is the same as the conveyance land, and the piercing processing land 1a.
It has a slightly larger diameter.

As shown in the figure, the top of the burnishing land 1g is formed into a convex strip having an arcuate cross section. The action of the burnishing land 1g will be explained with reference to FIG. 8. As the ram descends, the piercing land 1a formed at the tip of the piercing punch and the opening of the die (not shown) The workpiece W is sheared and perforated.

The convex strip 1h at the arcuate top of the burnishing land 1g having a diameter slightly larger than the piercing land 1a is press-fitted into the inner surface of the drilled hole Wa, and the inner surface of the hole Wa is plastically deformed and finished smoothly. Provide dimensional accuracy.

The workpiece W, which has been burnished by the burnishing land Ig, is lifted toward the top dead center by the friction between the burnishing land 1g and the hole wa of the workpiece W, as in the previous embodiment, and is reliably separated from the die. , it is detached and dropped from the piercing punch 1 by a stripper, carried out by air ejected from an air ejection nozzle controlled by a limit switch, etc., and transported and stored in a stocker or the like.

In the above description, the piercing punch is provided with only one land for conveyance and one land for varnishing, but it is also possible to provide a plurality of them in a stacked manner, if necessary.

(Effect) A conveying land with a slightly larger diameter than the piercing land is provided on the shank side of the piercing land provided at the tip of the piercing punch via a reduced diameter part, so the workpiece can be removed from the die. However, the friction between the inner surface of the hole drilled in the workpiece and the outer circumferential surface of the conveyance land ensures reliable workpiece conveyance, and eliminates the trouble of double-hitting the workpiece due to conveyance errors. Breakage of the punch can be prevented and work efficiency can be improved. Furthermore, by providing a burnishing land with a slightly larger diameter than the piercing land in place of the above-mentioned conveyance land, it is possible to not only carry out the workpiece, but also to carry out piercing and burnishing separately. The process can be performed simultaneously, simplifying the machining process, and making it possible to press with high precision at low cost.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of a piercing punch for explaining the present invention in detail, Fig. 2 is an enlarged explanatory diagram of section A in Fig. 1, and Figs. 3 to 6 are effects of the piercing punch of the present invention. FIGS. 7 and 8 are explanatory views for explaining the state, FIGS. 7 and 8 are explanatory views for explaining other embodiments, and FIG. 9 is an explanatory view for explaining a conventional piercing punch. 1... Punch for piercing, 1a... Land for piercing, 1b... Stem, 1c... Shank, 1d
...Reduced diameter part, 1e... Land for conveyance, 1g... Land for burnishing, 2... Ram, 4... Die, 5... Succeeding, tripper

Claims (1)

[Scope of Claims] 1) A piercing land for piercing a workpiece is formed at the tip of the stem of the punch, and the piercing is performed at a portion of the stem closer to the shank than the piercing land through the reduced diameter part. A conveying land having a diameter slightly larger than that of the piercing land is provided, and this conveying land enters the hole of the workpiece drilled by the piercing land during piercing operation, and the conveyance land enters the hole of the workpiece after piercing. A piercing punch characterized by contacting the inner surface of a hole with sufficient frictional force to pull the workpiece out of the die. 2) At the tip of the stem of the punch, a land for piercing is formed to pierce the workpiece, and a part of the stem that is closer to the shank than the land for piercing is slightly larger than the land for piercing through the reduced diameter part. A burnishing land consisting of a convex strip having a diameter of an arcuate cross section is provided, and the burnishing land is press-fitted into the inner surface of the hole of the workpiece drilled by the piercing land during piercing operation. A piercing process characterized in that the workpiece is burnished, and as the punch rises, the workpiece is extracted from the die by the frictional force between the outer peripheral surface of the burnishing land and the inner surface of the hole in the workpiece. Punch for use.