JP2005224806A - Punching apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a punching apparatus which can relax the stress concentration at the head portion of a punch, and can be easily mounted to a punch plate. <P>SOLUTION: The punching apparatus comprises a stem portion 4 which is inserted into a through hole 10 of the punch plate 9 and is held therein, and a punch 2 having a head portion 5 at the tail end of the stem portion 4. The head portion 5 is formed as a tapered shape 6 in which the diameter gradually increases from the stem portion 4 toward the tail end. A cylindrical body 3 is provided so as to be received in a counter bore portion 11 with a clearance around its periphery, the counter bore portion 11 being formed at a tail end of the through hole 10 of the punch plate 9 so as to have the diameter larger than that of the through hole 10. A tapered hole portion 7 for receiving the head portion 5, and a straight hole portion 8, into which the stem portion 4 is inserted with a clearance and which is continued to the tapered hole portion 7, are formed in the cylindrical body 3. The tapered hole portion 7 is formed such that the end face of the head portion 5 is exposed outside the end face of the cylindrical body 3. The cylindrical body 3 is made of a metallic material having the hardness lower than that of the punch. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a punch device used for drilling or the like.

  Conventionally, as shown in FIG. 6A, a punch 2 a having a shaft portion 4 and a head portion 5 having a diameter larger than that of the shaft portion 4 at the tail end of the shaft portion 4 is known (for example, see Patent Document 1). ).

  As shown in FIG. 6B, the punch 2a is attached to the punch plate 9 attached to the press 13 via the backing plate 12. For example, a plurality of punches 2a are attached to the punch plate 9, and used as a multi-row punching male die for drilling. The punch 2 a has a shaft portion 4 fitted and held in a through-hole 10 formed at a predetermined position of the punch plate 9, while a head 5 is formed at the tail end of the through-hole 10. It is accommodated in a counterbore part 11 having a larger diameter.

  In the apparatus shown in FIG. 6B, when the press machine 13 is lowered, the workpiece W is punched by the tip of the shaft portion 4. When the press machine 13 is raised after the drilling process is finished, the bottom of the counterbore part 11 engages with the bottom surface of the head 5 of the punch 2a to pull out the punch 2a from the workpiece W. At this time, the axis of the punch 2a A frictional force due to the workpiece W acts on the tip of the portion 4. And the stress by this frictional force acts on the lower surface of the head 5.

  In general, in a structure having a uniform cross section, the stress is uniformly distributed. However, in the punch 2a, the head 5 protrudes at a right angle to the shaft portion 4. It has a structure in which the cross section suddenly changes at the corners. As a result, stress concentrates on the corner portion, and a crack is generated in the corner portion, so that the head 5 is easily broken, so-called head jumping is likely to occur.

  In order to alleviate the stress concentration on the corner portion of the head portion 5 and the shaft portion 4, as shown in FIG. 7A, the head portion 5 has a tapered shape in which the diameter gradually increases from the shaft portion 4 toward the tail. A so-called taper punch 2b is known (see, for example, Patent Document 2).

  As shown in FIG. 7B, the taper punch 2 b is a taper hole in which the shaft portion 4 is held by being fitted into the through hole 10 of the punch plate 9, while the head portion 5 is formed at the tail end of the through hole 10. It is accommodated in the part 19 and used in the same manner as the punch 2a shown in FIG. As a result, the stress when pulling out the punch 2b after the drilling is finished is uniformly applied to the tapered surface 6 of the peripheral surface of the head 5, and the stress concentration on the corner portion of the head 5 and the shaft portion 4 is concentrated. Can be relaxed.

However, in the configuration of FIG. 7B, the shape of the tapered hole portion 15 formed in the punch plate 9 is precisely matched with the shape of the tapered surface 6 of the head portion 5 and the through hole 10 is formed. There is an inconvenience that the hole axis and the hole axis of the tapered hole portion 19 must be precisely matched, and high-precision machining is required. In particular, at present, parts manufacturers that manufacture mold parts such as punches are different from mold manufacturers that manufacture molds, and die makers penetrate through punch plates according to taper punches purchased from parts manufacturers. The hole and the tapered hole are processed. The mold maker does not have a dedicated tool for machining the tapered hole that fits the taper punch, and it is difficult to machine the precise tapered hole as described above. For this reason, the taper punch is not as widespread as it has a remarkable effect of preventing skipping.
Japanese Utility Model Publication No. 56-117928 (FIG. 1 (b)) Japanese Utility Model Publication No. 56-117928 (FIG. 1 (a))

  It is an object of the present invention to provide a punching device that can eliminate such inconvenience, relieve stress concentration on the head of the punch, and can be easily attached to the punch plate.

  In order to achieve such an object, the present invention is a punch device comprising a punch having a shaft portion that is inserted and held in a through hole formed in a punch plate, and a head portion at the tail end of the shaft portion, The punch head has a tapered shape with a diameter gradually increasing from the shaft toward the tail, and the punch has a counterbore with a larger diameter than the through hole formed at the tail end of the through hole of the punch plate. A cylindrical body that can be stored with a gap is provided, and the cylindrical body is continuous with a tapered hole part that receives the head of the punch and a tapered hole part through which the shaft part of the punch is inserted with a gap. A straight hole portion is formed.

  According to the said structure, the axis | shaft of this punch and the axis | shaft of this taper hole part correspond because the head part of the said punch is received by the taper hole part of the said cylindrical body. At this time, the axis of the tapered hole portion and the axis of the straight hole portion may be slightly shifted, but the straight hole portion is inserted through the punch shaft portion with a gap. Therefore, the shaft portion is inserted without interfering with the straight hole portion. Therefore, the punching device can be manufactured easily and inexpensively without requiring high-precision machining to precisely match the axis of the tapered hole portion and the axis of the straight hole portion of the cylindrical body. it can.

  If the mold part manufacturer manufactures the cylindrical body paired with the punch, the taper of the cylindrical body is used by using a dedicated tool that matches the taper shape of the head of the punch. The hole can be easily machined to match the tapered shape of the head, which is reasonable.

Next, the punch device of the present invention is held by the shaft portion of the punch being inserted through the through hole of the punch plate in a state where the punch and the cylindrical body are combined as described above. The punch head is housed in the counterbore together with the cylindrical body. At this time, in the punch plate, the axis of the through hole and the axis of the counterbore part may be slightly shifted,
Since the cylindrical body can be stored in the counterbore part with a peripheral gap, the cylindrical body is stored in the counterbore part without interfering with the counterbore part. Therefore, the punching device does not require high-precision processing such that the axis of the through hole and the axis of the counterbore portion precisely coincide with the punch plate. Can be easily attached.

  In the punch device of the present invention attached to the punch plate as described above, the punch plate is mounted on a press machine via a backing plate, and the press machine is lowered with respect to the work to be attached to the work. Drilling can be performed. When the press is raised after completion of the drilling process, the punch is pulled out from the workpiece. However, since the frictional force of the workpiece acts on the punch, stress is applied to the head of the punch.

  However, the stress when pulling out the punch is applied to the peripheral surface of the head formed in a tapered shape through the tapered hole portion of the cylindrical body. Therefore, according to the punch device of the present invention, the stress concentration on the head of the punch can be relaxed, and the occurrence of head jump can be reduced.

  The tapered hole portion of the cylindrical body only needs to be able to transmit the stress to the tapered peripheral surface of the head, and does not accommodate the entire head of the punch. It is sufficient that at least a part of the part is accepted. Therefore, in the punch device of the present invention, the tapered hole portion of the cylindrical body is formed such that the end surface of the head portion is raised outward from the end surface of the cylindrical body.

  By doing so, when the backing plate is securely brought into contact with the end face of the head and the hole is drilled in the workpiece, the shaft portion of the punch is axially moved in the through hole. It can be prevented from moving to the tail. When the drilling process is performed, if the shaft portion moves in the through hole, the shaft portion and the through hole are worn, and the shaft portion is not completely held by the through hole.

  Moreover, the punch apparatus of this invention WHEREIN: The said cylindrical body consists of a metal material softer than the said punch. In this case, even if the shape of the tapered hole portion does not exactly coincide with the tapered shape of the side surface of the head of the punch, it can gradually become familiar with the tapered shape of the side surface of the head by repeated use. it can. Therefore, the taper hole portion does not require high-precision processing that precisely matches the shape of the taper hole portion and the taper shape of the side surface of the head, and the cost can be reduced.

  Next, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. 1 is an explanatory cross-sectional view showing an embodiment of the punch device of the present invention, FIG. 2 is an explanatory cross-sectional view showing a state in which the punch device of FIG. 1 is attached to a punch plate, and FIG. 3 is a punch device of FIG. FIG. 4 is an explanatory sectional view showing a state in which the punching device of another embodiment is attached to the punch plate, and FIG. 5 is still another embodiment of the punching device of the present invention. It is explanatory sectional drawing which shows this.

  As shown in FIG. 1A, the punch device 1 of this embodiment includes a punch 2 and a bush 3 that is a cylindrical body. The punch 2 includes a shaft portion 4 and a head portion 5 formed at the tail end of the shaft portion 4. The head 5 is formed in a tapered shape that gradually increases in diameter from the shaft portion 4 toward the tail, and the peripheral surface of the head 5 is a tapered surface 6. The punch 2 is manufactured from tool steel or cemented carbide, and the tip portion of the shaft portion 4 becomes a punch portion.

On the other hand, the bush 3 is formed with a tapered hole portion 7 for receiving the head portion 5 of the punch 2 and a straight hole portion 8 through which the shaft portion 4 is inserted continuously from the tapered hole portion 7. shank 4 of the punch 2 is can be inserted at intervals C ₁ is. The bush 3 is softer and softer than the punch 2, for example, a metal material having an HRC (working hardness) of about 40 is cut to form a straight hole portion 8 first, and then a tapered hole portion 7 communicating with the straight hole portion 8. It is manufactured by forming. At this time, the axis of the tapered hole portion 7 and the axis of the straight hole portion 8 are made to coincide with each other.

  As shown in FIG. 1 (b), the punch device 1 is assembled with the punch 2 and the bush 3 by inserting the shaft portion 4 of the punch 2 into the straight hole portion 8 of the bush 3. At this time, the head 5 of the punch 2 is aligned with the axis of the punch 2 and the axis of the tapered hole 7 by the taper surface 6 being guided by the tapered hole 7 of the bush 3.

At this time, the straight hole portion 8 only needs to be formed so that the shaft portion 4 of the punch 2 can be inserted with the gap C ₁ therebetween, and the axis of the taper hole portion 7 and the axis of the straight hole portion 8 are precisely matched. It is not necessary to be processed with high accuracy. The shaft portion 4 can be inserted through the straight hole portion 8 with the gap C ₁ , so that even when the shaft of the tapered hole portion 7 and the shaft of the straight hole portion 8 are slightly displaced, The straight holes 8 can be inserted without interfering with each other.

  As shown in FIG. 2, the punch device 1 in which the punch 2 and the bush 3 are assembled is attached to the punch plate 9 by inserting the shaft portion 4 of the punch 2 into the through hole 10 of the punch plate 9. The At this time, the shaft portion 4 is lightly press-fitted into the through hole 10, whereby the punch device 1 is held by the punch plate 9. For example, the punch plate 9 holds a plurality of punches 2 and is used as a multi-row punching male mold, but may hold only one punch 2.

  When the punch device 1 is attached to the punch plate 9, the bush 3 is accommodated in a counterbore portion 11 formed at the tail end of the through hole 10. The counterbore part 11 is formed larger in diameter than the through-hole 10 so that the axis of the through-hole 10 and the axis of the counterbore part 11 coincide with the tail end of the through-hole 10.

Countersunk portions 11 may be formed so as to lie a gap C ₂ between the periphery of the bushing 3, with high precision such that the axes of the spot facing 11 of the through hole 10 coincides precisely It does not have to be processed. Bushing 3, by residing clearance C ₂ between the counterbore portion 11, even when the axis of the shaft and the spot facing 11 of the through hole 10 as is slightly shifted, without interfering with each other It can be accommodated in the spot facing 11.

  As shown in FIG. 3, the punch plate 9 that holds the punch device 1 is further attached to the press machine 13 via a backing plate 12 that is in contact with the end face of the head 5. The punching device 1 lowers the press machine 13 to perform drilling on the workpiece W placed on the female die 14 corresponding to the shaft portion 4 of the punch 2. FIG. 3 shows a state where the drilling process is completed.

  When the press machine 13 is raised after completion of the drilling process, the shaft portion 4 is pulled out from the workpiece W. At this time, a frictional force due to the workpiece W acts on the shaft portion 4, and the stress due to the frictional force is applied to the punch plate. 9. Acts on the head 5 via the bush 3. However, the head 5 is in contact with the bush 3 by the taper surface 6, and the sudden change in the cross section between the head 5 and the shaft portion 4 is reduced by the taper surface 6, so that the stress concentrates on a specific local portion. This can be suppressed.

  Since the bush 3 is formed of a metal material having a hardness of about HRC 40 lower than that of the punch 2 as described above, the shape of the tapered hole portion 7 does not exactly match the shape of the tapered surface 6 of the punch 2. Also good. The tapered hole portion 7 of the bush 3 made of the metal material can be gradually adapted to the shape of the tapered surface 6 of the punch 2 by repeated use.

  By the way, the taper hole portion 7 is formed so that the taper surface 6 of the head portion 5 of the punch 2 is in contact with the taper hole portion 7 over the boundary portion with the shaft portion 4, and the bush 3 does not have the straight hole portion 8. Can be considered. However, in this case, the axial thickness of the portion of the bush 3 that receives the portion of the tapered surface 6 near the shaft portion 4 (the minimum diameter portion of the tapered hole portion 7) becomes thin, and the punch 2 is pulled out from the workpiece W. In addition, the minimum diameter portion of the tapered hole portion 7 is bent so as to bite into the bottom portion of the spot facing portion 11. Therefore, deformation (sagging) occurs in the opening of the through hole 10 at the bottom of the counterbore part 11.

  On the other hand, the bush 3 of the present embodiment includes a straight hole portion 8, and a thickness corresponding to the length of the straight hole portion 8 is secured even in the minimum diameter portion of the tapered hole portion 7. Therefore, the sag due to the bending of the minimum diameter portion of the tapered hole portion 7 can be prevented.

  In the punching device 1, the backing plate 12 is preferably in contact with the end surface of the head 5 when the punch plate 9 is mounted on the press machine 13. Even if there is a gap between the backing plate 12 and the end face of the head 5, the drilling can be performed. In this case, the shaft portion 4 is moved to the gap every time the drilling is performed. It will move up and down with the width of. Since the shaft portion 4 is lightly press-fitted into the through-hole 10, if the vertical movement is repeated, the shaft portion 4 is worn due to bending with the through-hole 10, and a gap is formed between the through-hole 10 and is not sufficiently held.

  Here, in the present embodiment, the tapered hole portion 7 is formed so that the end surface of the head portion 5 is flush with the end surface of the bush 3 on the tail side of the punch 2. If it is slightly larger than the design value, the end face of the head 5 becomes lower than the end face of the bush 3, and a gap is formed between the backing plate 12 and the end face of the head 5. On the other hand, as shown in FIG. 4, if the tapered hole portion 7 is formed so that the end surface of the head portion 5 protrudes outward from the end surface of the bush 2 on the tail side of the punch 2, the tapered hole portion 7 is formed with a processing tolerance. Even if formed slightly larger, the end face of the head 5 does not become lower than the end face of the bush 3, which is advantageous.

  Even if the tapered hole portion 7 is configured as shown in FIG. 4, the end surface of the head portion 5 may not be flush with the punch plate 9 depending on the depth of the spot facing portion 11. In such a case, adjust the end surface of the head 5 to be flush with the end surface of the punch plate 9 by interposing a shim between the bush 3 and the bottom of the counterbore portion 11. Can do.

The punch 2 of each of the above embodiments is formed in a tapered shape in which the head portion 5 gradually increases in diameter from the shaft portion 4 toward the tail, and the peripheral surface of the head portion 5 is a tapered surface 6. It is directly connected to the shaft portion 4. However, straight holes 8 of the bushing 3, since at intervals C ₁ between the shaft portion 4 of the punch 2, as shown in FIG. 5 (a), a head 5 and the shaft portion 4 is It may be connected via the curved surface portion 15.

As described above, since the stress concentration occurs at the site where the cross section changes suddenly, the curved surface portion 15 is provided, and the connection from the shaft portion 4 to the head portion 5 is made smooth so that the head portion 5 and the shaft portion 4 are connected. It is possible to further suppress the stress concentration on the connection part. In this case, as shown in FIG. 5 (b), the curved surface portion 15 is accommodated in the straight hole portion 8 at the interval C _1, so that the curvature radius of the curved surface portion 15 is accommodated in the straight hole portion 8. Can be as large as possible in the range.

  The head 5 may include a cylindrical portion 16 above the tapered surface 6. The cylindrical portion 16 is chamfered 17 at the upper end, and the inner peripheral surface 18 of the chamfer 17 has the same diameter as the shaft portion 4. The head 5 is further improved in strength by including the cylindrical portion 16 and the chamfer 17, and can be prevented from being damaged when the punch 2 is pulled out.

  In each of the above embodiments, the punch 2 includes the shaft portion 4 having the same diameter up to the tip, and the tip portion of the shaft portion 4 is drilled using the punch portion. It is good also as a shape punch part. In each of the above embodiments, the punch for punching has been described. However, the present invention can be similarly applied to a forging punch for forming a recess in a forged product.

Explanatory sectional drawing which shows one Embodiment of the punch apparatus of this invention. Explanatory sectional drawing which shows the state which attached the punch apparatus of FIG. 1 to the punch plate. Explanatory sectional drawing which shows the drilling process by the punch apparatus of FIG. Explanatory sectional drawing which shows the state which attached the punch apparatus of other embodiment to the punch plate. Explanatory sectional drawing which shows other embodiment of the punch apparatus of this invention. Explanatory sectional drawing which shows one form of the conventional punch. Explanatory sectional drawing which shows the other form of the conventional punch.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Punch apparatus, 2 ... Punch, 3 ... Cylindrical body, 4 ... Shaft part, 5 ... Head part, 7 ... Tapered hole part, 8 ... Straight hole part, 9 ... Punch plate, 10 ... Through-hole, 11 ... Seat Guri part.

Claims (3)

A punch device comprising a punch having a shaft portion inserted and held in a through-hole formed in a punch plate, and a head portion at the tail end of the shaft portion,
In what is formed in a taper shape in which the diameter of the punch head gradually increases from the shaft toward the tail,
A cylindrical body that can be accommodated in a counterbore portion having a diameter larger than that of the through hole formed at the tail end of the through hole of the punch plate with a surrounding clearance, and the cylindrical body is a taper that receives the punch head. A punching device comprising: a hole portion; and a straight hole portion continuous with a tapered hole portion through which a shaft portion of the punch is inserted with a gap.   2. The punching device according to claim 1, wherein the tapered hole is formed so that an end surface of the head is raised outward from an end surface of the cylindrical body.   3. The punch apparatus according to claim 1, wherein the cylindrical body is made of a metal material that is softer than the punch.

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