JPH0860204A - Straightening press - Google Patents

Abstract

PURPOSE: To ameliorate the difficulty in removing of a lower punch by adhesion of oil with a straightening press using oil for lubrication. CONSTITUTION: Hollow grooves 33 are radially formed on the butt surface 31 of a lower punch 4 against a lower punch holder 13. These hollow grooves 33 communicate from the inner periphery of the lower punch 4 to the outer periphery. A better effect is obtd. if the hollow grooves 33 are inclined with the diametral direction of the lower punch 4. As a result, the contact area of the lower punch 4 and the lower punch holder 13 decreases. The oil bleeds out and air enters via the hollow grooves 33. As a result, the adhesive power between the lower punch 4 and the lower punch holder 13 decreases.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a straightening press used in powder metallurgy.

[0002]

2. Description of the Related Art In powder metallurgy, a raw material powder is first compressed by a powder molding press to form a green compact (powder molding step), and then the green compact is heated in a sintering furnace and sintered. (Sintering step) Further, the sintered body after the sintering is repressurized by a straightening press to finish to a predetermined size (straightening step)
Is done. In this straightening process, a lubricant such as oil is applied to the work in order to lubricate the straightening die.

The straightening die comprises a die, an upper punch, a lower punch, a core rod, and the like, and these die are appropriately exchanged according to the switching of the work. That is, the die such as the punch is detachably attached to the die holder on the press body side,
Conventionally, the abutting surface of a die such as a punch and its holder has been formed in a flat shape as a whole except for a through hole of a bolt.

[0004]

By the way, as described above, a lubricant such as oil is applied to the work during the straightening process, but this lubricant gradually accumulates in the straightening mold, especially the lower metal mold. A large amount of lubricant adheres to the mold and its holder. Then, the lubricant adheres to, for example, the abutting surface between the lower punch and its holder, but in the past, the entire abutting surface between the die of the punch and its holder was flat, so that the lubricant Adhesion creates a vacuum between the die of the punch and its holder, and the suction force between the two becomes very large, requiring a large amount of force to remove the punch and the like, which is a time-consuming task. It was

The present invention is intended to solve such a problem, and the mold can be easily removed from the mold holder with a small force, thereby improving the efficiency and safety of mold replacement. The purpose of the present invention is to provide a straightening press.

[0006]

DISCLOSURE OF THE INVENTION The present invention is intended to achieve the above object, and a straightening press according to the invention of claim 1 is provided with a mold and a detachable mold provided on the press main body side. A die holder to be attached is provided, and a concave groove communicating with the outer periphery of the butting surface is formed on one of the butting surfaces of the die and the die holder.

According to a second aspect of the present invention, in the straightening press according to the first aspect of the present invention, the die is a cylindrical lower punch into which a core rod is slidably fitted, and the groove is formed.
The lower punch and the die holder are communicated with each other on the outer circumference and the inner circumference of the abutting surface.

According to a third aspect of the present invention, the lower punch is provided with a clamp ring that locks the lower punch on the die holder by rotating the lower punch, and releases the locking.
The butt surface is inclined with respect to the radial direction.

[0009]

In the straightening press according to the first aspect of the invention, the contact area between the die and the die holder itself is formed by the concave groove formed on one of the butting surfaces of the die and the die holder and leading to the outer periphery of the abutting surface. Is smaller, the lubricant between the abutting surfaces is discharged through the recessed groove, and when the mold is removed, air easily enters between the abutting surfaces, and the lubricant causes the mold and mold holder to Adhesion becomes small.

Further, in the straightening press of the second aspect of the present invention, the butting is formed by the concave groove formed on the butting surface of the cylindrical lower punch which is a die and the die holder, and which communicates with the outer circumference and the inner circumference of the butting surface. The lubricant between the surfaces is better discharged, and air is more likely to enter between the abutting surfaces.

Further, in the straightening press of the third aspect of the present invention, by rotating the lower punch, the lower punch is locked to the mold holder by the clamp ring, or this locking is released. When the lower punch is rotated, the concave groove is inclined with respect to the radial direction of the abutting surface, so that the lubricant is discharged and the air is effectively introduced through the concave groove.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the straightening press of the present invention will be described below with reference to FIGS. The straightening press has a mold removably attached to the press body 1. As shown in FIG. 3, when the work 2 has an annular shape, the straightening press has a die 3, a lower punch 4 and an upper die. The punch 5 and the core rod 6 are used. The die 1 is for molding the outer peripheral surface of the work 2. The lower punch 4 is tubular and is fitted into the die 1 so as to be vertically slidable from below, and forms the lower end surface of the work 2. The upper punch 5 has a cylindrical shape and is fitted into the die 1 so as to be vertically slidable and insertable / detachable from above to form the upper end surface of the work 2. Further, the core rod 6 fitted in the lower punch 4 slidably in the vertical direction is fitted in the upper punch 5 so as to be slidable in the vertical direction and insertable / detachable to form the inner peripheral surface of the work 2. To do.

The die 3 is detachably attached to a die plate 11 on the press body 1 side by a die holder 12. Although not shown, the upper punch 5 and the core rod 6 are detachably attached to the upper punch holder and the core rod holder on the press body 1 side, respectively. Further, as shown in FIG. 1, the lower punch 4 is detachably attached to a lower punch holder 13 which is a die holder on the press body 1 side.

The attachment of the lower punch 4 to the lower punch holder 13 will be described in detail. Lower punch 4
Is a disc-shaped lower punch base 17 on the lower surface of the lower punch body 16.
Is fixed in a flange shape and horizontally. Also, the lower punch holder 13 is an adapter on the press body base 18.
Fixed through 19. The lower punch 4 is locked to the lower punch holder 13 by the clamp ring 21 and released from the lock as the lower punch 4 rotates in the circumferential direction. That is, the lower punch base 17
Has a plurality of receiving projections 22 on the outer peripheral surface, while the clamp ring 21 provided on the lower punch holder 13 is
The lower punch base 17 has a plurality of locking projections 23, which are engaged with the receiving projections 22 of the lower punch base 17 so as to be engageable with and disengageable from each other, in the upper portion of the inner peripheral surface. The lower punch base 17 and the lower punch holder 13 respectively have through holes 25 and 26 at their central portions, which pass through the through holes 24 inside the lower punch body 16 having a tubular shape, in order to allow the core rod 6 to pass therethrough. .

Further, the abutting surfaces 31, 32 of the lower punch base 17 and the lower punch holder 13 are horizontal surfaces, but the abutting surface 31 of the lower punch base 17 has a plurality of lines as shown in FIG. The linear concave grooves 33 are radially formed. These recessed grooves 33 extend from the through hole 25 forming the inner circumference of the lower punch base 17 to the outer circumference of the lower punch base 17.
Along with this, the concave groove 33 forms a tangent line to the circular through hole 25, and is inclined outward in the clockwise direction with respect to the radial direction of the lower punch base 17. This direction is the rotation direction when the lower punch 4 is removed. The lower punch base 17 has a diameter of about 200 mm, while the groove 33 has a width of about 2 mm and the groove 33 has a depth of about 1.5 mm. Groove 33
The width and depth of the lower punch 4 should be appropriately determined according to the dimensions of the lower punch 4. In the case of the dimensions of the lower punch 4 of this embodiment, the width of the concave groove 33 is about 1 to 3 mm, and the width of the concave groove 33 is 33 mm. Depth is 1-2
It is suitable to set to about mm. The groove 33 is processed by a grinder or the like.

Next, the operation of the above configuration will be described. At the time of straightening, the work 2 is previously lubricated with oil. After the upper punch 5 is removed from the die 3, the work 2 with oil is loaded into the die 3 by its ascent, and then the upper punch 5 is lowered to lower the die 3.
Fit inside. As a result, the work 2 is pressed by the punches 4 and 5 between the die 3 and the core rod 6, and the work 2 is straightened. After that, the upper punch 5 rises to come off the die 3, and the die 3 comes down to take out the work 2.

When switching the work 2 to be straightened, the mold is replaced. In particular, the lower punch 4 is removed from the lower punch holder 13 after being unlocked by the clamp ring 21 by turning it counterclockwise as viewed from above. Then, the new lower punch 4 is butted against the lower punch holder 13 and rotated clockwise to be locked to the lower punch holder 13 by the clamp ring 21.

By the way, as described above, oil is applied to the work 2 during straightening, but this oil gradually accumulates in the mold, and also on the abutting surfaces 31, 32 of the lower punch 4 and the lower punch holder 13. It becomes attached. However, the concave groove 33 formed on the abutting surface 31 of the lower surface of the lower punch base 17
As a result, the contact area between the lower punch base 17 and the lower punch holder 13 is reduced, and the abutting surfaces 31, 32 are
The oil in between is discharged through the concave groove 33 that communicates with the inner circumference and the outer circumference of the lower punch base 17, and when the lower punch 4 is removed, air easily enters between the abutting surfaces 31, 32 through the concave groove 33. Therefore, the adhesive force between the lower punch 4 and the lower punch holder 13 due to the oil is reduced. Moreover, since the concave groove 33 is tilted in the counterclockwise direction toward the outside with respect to the radial direction of the lower punch base 17 as viewed from above, the counterclockwise rotation is performed to remove the lower punch base 17 from the lower punch holder 13. When turned in the direction, the oil is effectively discharged to the outside through the groove 33, and the inflow of air is also effectively made. In this way, the lower punch 4 can be easily removed from the lower punch holder 13 with a small force. As a result, the efficiency of the replacement work of the lower punch 4 is improved, the setup time can be shortened, and the work safety is improved. This is because the oil is more likely to accumulate,
Moreover, the relatively large lower punch 4 is particularly effective. Further, it is particularly effective for a large straightening press in which the contact area between the lower punch 4 and the lower punch holder 13 is large and the weight of the lower punch 4 is also large.

Further, in order to reduce the adhesion force due to the oil, a concave groove is used.
Although it is better to increase the size of the groove 33, the groove 33 is not originally preferable in terms of mold strength. Due to the balance between the two, as described above, the diameter of the lower punch base 17 is about 200 mm, while the width of the concave groove 33 is about 1 to 3 mm and the depth of the concave groove 33 is about 1 to 2 mm. Is appropriate.

The present invention is not limited to the above embodiment, and various modifications can be made. For example,
In the above-described embodiment, the lower punch 4 is locked to the lower punch holder 13 by the clamp ring 21, but as in the second embodiment shown in FIG. 4, the lower punch 4 is attached to the lower punch holder 13 by bolts. It may be fixed.
In this case, a plurality of bolt holes 36 through which the bolts pass are formed in the peripheral portion of the lower punch base 17, but the bolt holes 36 are formed in order to prevent the strength and damage of the bolt portion of the lower punch 4 from being reduced. It should be formed so as not to overlap the groove 33. On the other hand, in the case of the clamp ring system as in the first embodiment, the bolt holes are unnecessary, so that it is possible to form a larger number of concave grooves 33.

Further, the shape of the concave groove is not limited to that of the above embodiment. For example, as in the third embodiment shown in FIG.
33 may be formed in a curved shape. Particularly, when the plurality of concave grooves 33 are formed in a spiral shape with respect to the center of the lower punch holder 13,
It is effective for oil discharge and air inflow. On the other hand, like the fourth embodiment shown in FIG. 6, the grooves 33 may be formed radially along the radius of the lower punch holder 13.

Further, in the above embodiment, the concave groove 33 is formed in the abutting surface 31 on the lower punch 4 side among the abutting surfaces 31, 32 of the lower punch 4 and the lower punch holder 13, but the lower punch holder 13 is butted. A groove may be formed on the surface 32.
Furthermore, you may form a concave groove in both abutting surfaces.

Further, the present invention can be applied to dies other than the lower punch.

[0024]

According to the first aspect of the present invention, since one of the abutment surfaces of the die and the die holder is provided with a recessed groove that communicates with the outer periphery of the abutment surface, the die and die are made of a lubricant. The adhesive force with the holder becomes small, the mold can be easily removed from the mold holder, the efficiency of mold replacement is improved, and the safety is also improved.

This is effective for a relatively large lower punch, as in the second aspect of the invention, in which lubricating oil is more likely to accumulate, and for a cylindrical lower punch, the concave groove is called the lower punch. It is more effective if the outer surface and the inner surface of the abutting surface with the die holder are communicated with each other.

Further, according to the third aspect of the invention, by rotating the lower punch, the lower punch is locked and released from the die holder by the clamp ring, while the locking is released. Since it is inclined with respect to the radial direction of the abutting surface, when the lower punch is rotated and removed, the lubricant is more effectively discharged and air is more effectively introduced, and the lower punch is more easily removed.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of the vicinity of a lower punch showing a first embodiment of a straightening press of the present invention.

FIG. 2 is a bottom view of the upper and lower punches.

FIG. 3 is a cross-sectional view of the vicinity of the same die.

FIG. 4 is a bottom view of the lower punch showing the second embodiment of the straightening press of the present invention.

FIG. 5 is a bottom view of the lower punch showing the third embodiment of the straightening press of the present invention.

FIG. 6 is a bottom view of the lower punch showing the fourth embodiment of the straightening press of the present invention.

[Explanation of symbols]

 1 Press body 3 Die (die) 4 Lower punch (die) 5 Upper punch (die) 6 Core rod (die) 13 Lower punch holder (die holder) 21 Clamp ring 31, 32 Butt face 33 Recessed groove

Claims (3)

[Claims] 1. A mold and a mold holder, which is provided on the press body side and is detachably attached to the mold,
On one of the butting surfaces of these mold and mold holder,
A straightening press characterized in that a concave groove is formed which communicates with the outer periphery of the abutting surface. 2. The die is a cylindrical lower punch into which a core rod is slidably fitted, and the concave groove is formed on an outer periphery and an inner surface of a butting surface of the lower punch and a die holder. The straightening press according to claim 1, wherein the straightening press communicates with the circumference. 3. A clamp ring that locks and unlocks the lower punch to a die holder by rotating the lower punch, wherein the groove is inclined with respect to the radial direction of the abutting surface. Claim 2 characterized by the above.
Straightening press as described.