JP2015044222A - Mold release device for hollow shaft forging - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold release device that can surely carry out a mold release with no damage of a hollow shaft forging even when the mold release is difficult because of a contact of the forging with an upper die.SOLUTION: A mold release device provided in a forward and backward extrusion forging apparatus that manufactures a hollow shaft forging 37 by pressing a projection punch 3 that is an upper die against a preform loaded into a lower die 2 comprises a small-diameter step formed in the outer peripheral surface of the punch 3, a punch ring 11 that is disposed on the outer peripheral surface of the punch 3 and has a claw part corresponding to the step to enable the claw part to be lifted up and down by engagement with the step, an upper cylinder that is disposed above the punch ring 11 and pushes the punch ring 11 out downward, and an upper knock-out rod 14 that is disposed between the upper cylinder and the punch ring 11 to keep the upper end part in contact with the upper cylinder, and the lower end part in contact with the upper end face of the punch ring 11 to push the punch ring 11.

Description

  The present invention relates to a technique for forging a hollow shaft forged product made of titanium using a mold, and more particularly to a mold release device for releasing a hollow shaft forged product from a mold.

In general, titanium alloys such as Ti-6Al-4V have excellent mechanical properties and heat resistance, and are therefore used for structural members such as engine members or chassis of transportation equipment such as aircraft and vehicles.
As a method of forging a hollow forged product (hollow shaft forged product) used for the structural member described above using such a titanium alloy, a hot extrusion forging method (hot upset forging method) using a die is used. Used. In the hot extrusion forging method, a heated work material is charged into a mold that is preliminarily modeled with a product shape, and the work material is stretched to a shape along the mold while maintaining a high temperature state. Forging while deforming. Using the hot extrusion forging method, a hollow forged product that is more tenacious than other processing methods and excellent in mechanical properties such as impact fracture resistance can be obtained because the metal flow along the product shape is obtained during deformation during forging. Can be obtained.

As a technique for forging a hollow forged product, for example, there are those disclosed in Patent Documents 1 and 2.
In Patent Document 1, a hollow rod-shaped hard material subjected to hole processing is formed by performing upsetting so as not to block the hole at the end portion of the hollow rod-shaped difficult-to-work material subjected to hole processing, and then performing the hole processing. A die-forging method for difficult-to-work materials in which a forging punch is pushed into a hole in the workpiece and die-forged is disclosed.

  In Patent Document 2, a groove is formed on the outer periphery of the large-diameter portion of the hollow part through the tooth profile of the large-diameter tooth forming die, and the small diameter of the hollow component is formed through the tooth profile of the lower punch and the tooth profile of the small-diameter tooth forming die. In the method for forming the inner and outer diameter grooves of the hollow part in which grooves are formed on the inner and outer peripheries of the part, the outer diameter of the large diameter part of the hollow part material is substantially the same as the outer diameter of the tooth form of the large diameter tooth forming die And the inner and outer diameters of the small diameter portion of the material of the hollow part are set to be substantially the same diameter as the intermediate diameters of the tooth shape of the lower punch and the tooth shape of the small diameter tooth forming die, A method for forming inner and outer diameter grooves of a hollow part is disclosed in which molding is started by simultaneously abutting the peripheral tip portion with the small diameter tooth forming die and the lower punch, and then molding the large diameter portion.

JP-A-6-339743 JP-A-5-61015

  As disclosed in Patent Document 1, extrusion forging for producing a trumpet-shaped hollow product using a difficult-to-work material such as a titanium alloy has been conventionally performed. However, in recent years, hollow forged products (hollow shaft forged products) formed by hot extrusion forging are often manufactured through a forging process involving complex deformation that imparts high strain in order to improve mechanical properties. It has become. A hollow forged product manufactured by such a complicated forging process tends to be in close contact with the mold, and it is often difficult to release the mold, so that the molded hollow forged product is released without damaging it. And means are sought.

Therefore, means disclosed in Patent Document 2 as a knockout pin is used. The inner punch disclosed in Patent Document 2 can be seen as an upper die in a forging die, and the large-diameter tooth forming die and the small-diameter tooth forming die can be seen as a lower die. It can be said that it is a means for releasing the hollow part from the mold.
However, as in the hollow shaft forged product described above, when a complicated forging process that imparts high strain is performed, the convex upper mold and the hollow portion of the hollow shaft are in close contact with each other, and it is difficult to release the mold. It happens frequently. In order to release the hollow part in such a close contact state, it seems difficult even with the technique of Patent Document 2.

  Therefore, in view of the above-described problems, the present invention provides a mold release that can be reliably released without damaging the forged product even when the forged product of the hollow shaft is in close contact with the upper mold and the mold release becomes difficult. An object is to provide a mold apparatus.

In order to solve the above-described problems, the present invention takes the following technical means.
A mold release device for a hollow shaft forged product according to the present invention presses a convex punch, which is an upper die, against a workpiece which is a concave shape opened upward and is inserted into a lower die. This is a mold release device for a hollow shaft forged product provided in a front / rear extrusion forging device for producing a hollow shaft forged product by front / rear extrusion forging, and is formed on the outer peripheral surface of the base end side of the convex punch. A step portion having a small diameter and a claw portion disposed on the outer peripheral surface of the punch and corresponding to the step portion, and the claw portion is engaged with the step portion so as to be vertically movable. A ring member that is disposed above the ring member, and that is disposed between the pressure cylinder and the ring member, the upper end portion of the ring member being in contact with the pressure cylinder. And the lower end is phosphorus It abuts the upper end surface of the member, and having a knockout member for pushing the ring member.

  Preferably, the stepped portion is constituted by two or more grooves facing in the vertical direction.

  According to the mold release device for a hollow shaft forged product according to the present invention, even if the forged product of the hollow shaft is in close contact with the upper mold and the mold release becomes difficult, the mold is securely released without damaging the forged product. be able to.

It is a figure which shows the manufacture procedure of the hollow shaft forge goods by embodiment of this invention. It is a figure which shows the exploded view of the punch of the front back extrusion forging apparatus by this embodiment, and a mold release apparatus. It is a figure which shows the state before forging of the front back extrusion forging apparatus by this embodiment. It is a figure which shows the state in the forging of the front back extrusion forging apparatus by this embodiment. It is a figure which shows the state before mold release after the forge of the front back extrusion forging apparatus by this embodiment. It is a figure which shows the state after mold release after the forge of the front back extrusion forging apparatus by this embodiment. It is a figure which shows the modification of the punch by this embodiment, and a mold release apparatus.

  Hereinafter, a release device for a hollow shaft forged product according to an embodiment of the present invention will be described with reference to the drawings. The hollow shaft forged product (sometimes referred to as a shaft forged product) forged in the present embodiment is a large-sized hollow shaft forged used for an engine member of a transport device such as an aircraft or a vehicle or a structural member such as a chassis. It is a product. In addition, forging in the present embodiment is a forward side (lower side) along the reduction direction and a rear side along the direction opposite to the reduction direction with respect to the reduction direction by the molds (upper mold and lower mold). This is also called fore-and-aft extrusion forging because the material is deformed and flows to the side (upper side).

Before describing the mold release device 10 for a hollow shaft forged product according to the present embodiment, a method for forging the hollow shaft forged product will be described, and then the configuration of the mold release device 10 will be described.
A forging method (front-rear extrusion forging method) of a hollow shaft forged product will be described with reference to FIG. FIG. 1 is a diagram illustrating a manufacturing procedure of a hollow shaft forged product, in which FIGS. 1 (a) to 1 (d) illustrate a pre-forging process, and FIGS. 1 (e) to 1 (f) are front-rear extrusions. The forging process (main forging process) is shown.

In the forging method shown in FIG. 1, a concave work material (that is, a wasteland) 34 is formed through several pre-processes (pre-forging process) shown in FIGS. 1 (a) to 1 (d). As shown in FIG. 1 (e) to FIG. 1 (f), a hollow shaft forged product 37, which is the final product, is forged by fore-and-aft extrusion forging the molded wasteland using the front-rear extrusion forging device 1.
First, the pre-process (pre-forging process) shown in FIGS. 1 (a) to 1 (d) will be described.

The pre-forging step is a step of deforming a cast slab made of, for example, a titanium alloy (Ti-6Al-4V) into a wasteland having a concave center. The forging method performed in this embodiment uses α + β forging.
With α + β forging, the wasteland is heated to within the α + β temperature (approximately 950 ° C) range, and the material temperature and the equivalent strain during forging are controlled appropriately to satisfy the material characteristics. This is a forging heat treatment technology that creates product shapes (forged hollow shaft products).

  The process shown in FIG. 1A is a billet forging process in which a billet 30 forged from a slab to a predetermined diameter (thick diameter) is forged into an elongated (thin diameter) billet 31. In the billet forging process, a large billet (φ500 mm) is heated in an α + β temperature range (950 ° C.) in a heating furnace so that the heated slab becomes an elongated (thin diameter) billet having an outer diameter of about φ250 mm. Perform upset forging. The elongated billet 31 forged in the billet forging process is sent to the upset forging process shown in FIGS. 1 (b) and 1 (c).

The process shown in FIG. 1B and FIG. 1C is an upset forging process in which a long billet 31 is forged into a short billet 32 while being repeatedly reduced, and then forged into a substantially rectangular billet 33.
The rectangular billet 33 that has finished this upset forging process is sent to the hollow forging process shown in FIG.

In the step shown in FIG. 1 (d), a concave recess and a hole are formed in the central portion in the axial direction of a short rectangular billet 33 forged in an upset forging process using an upper die having a convex punch. It is a hollow forging process which manufactures the wasteland 34 in which was formed.
After the hollow forging process is finished, the wasteland 34 is sent to a drilling process (not shown), and the central portion around the axis of the wasteland 34 is drilled (penetrated) along the axial direction by punching forging and shearing. The In addition, you may penetrate the bottom part of the rough ground 34 of sectional view concave shape (U shape) by machining etc.

Before explaining the lubricant application step and the hollow shaft forging step shown in FIGS. 1 (e) to 1 (f), the front / rear extrusion forging device (hot) used in the hollow shaft forging step shown in FIG. 1 (f) The configuration of the extrusion forging apparatus 1 will be described.
As shown in FIG. 1 (f), the front / rear extrusion forging device 1 used in this embodiment is configured to form a heated rough ground (concave workpiece) 34 as a mold (lower mold 2 and upper mold described later). A hollow and funnel-shaped shaft forged product 37 is formed by deforming in a hot state along the shape of 3). The concave wasteland 34 is forged by the pre-process (pre-forging process) shown in FIGS. 1 (a) to 1 (d).

The front / rear extrusion forging device 1 has a mold for molding the shaft forged product 37. This mold includes a lower mold 2 on which a wasteland 34 is inserted and placed, and an upper mold (a punch which will be described later) 3 that presses down the wasteland 34 placed on the lower mold 2 from above. It has a configuration that can be divided into two parts, upper and lower.
In addition to this die, the front / rear extrusion forging device 1 includes a lower knockout bar 4 that lifts the shaft forged product 37 from the lower die 2 and releases it, and a release that releases the shaft forged product 37 from the upper die 3. A mold apparatus 10 and an upper cylinder (pressing cylinder) 5 that presses a punch ring 11 that is a constituent member of the mold release apparatus 10 are provided. The upper cylinder 5 is disposed above a punch ring (ring member) 11 that comes into contact with the shaft forging 37 in close contact with the upper mold 3 from above, and pushes the punch ring 11 downward from the upper mold 3. This is a cylinder for releasing the forged shaft 37.

The lower mold 2 includes a shaft-shaped hole portion 21 and a funnel-shaped recess portion (upsetting portion) 22 formed so as to be connected to the upper portion of the hole portion 21. A concave wasteland 34 is inserted into the upsetting portion 22.
Specifically, a concave portion 22 that is a funnel-like hole is formed in the center in the width direction of the lower mold 2 and on the upper side thereof, and the inner diameter thereof is slightly larger than the outer diameter of the wasteland 34. The inside can be charged through the wasteland 34 from above to below.

  The funnel-shaped recess 22 is composed of a tapered conical surface 23 whose diameter increases so as to extend toward the upper portion, and a cylindrical flange hole portion formed so as to be connected to the upper portion of the conical surface 23. ing. The conical surface 23 is formed such that the inner diameter gradually decreases (decreases) as it goes downward, and the rough ground 34 can be placed on the conical surface 23. Further, the opening diameter of the flange hole portion is a diameter slightly larger than that of the rough ground 34, that is, a diameter to which the outer diameter of the rough ground 34 fits and comes into surface contact. In other words, the conical surface 23 and the inner peripheral wall of the flange hole portion are configured to support the wasteland 34 by making surface contact with the outer periphery of the wasteland 34, and the shaft center and lower metal along the vertical direction of the wasteland 34 are supported. The axis along the vertical direction of the mold 2 (concave portion 22) substantially coincides. That is, the charged wasteland 34 can be centered by charging the wasteland 34 into the lower mold 2 (recess 22).

A shaft-shaped hole (through hole) 21 having a smaller diameter than the rough ground 34 (inner diameter of the flange hole) is formed at the center in the width direction of the lower mold 2 and below the recess 22. A lower knockout bar 4 to be described later passes through 21.
Below the hole 21 of the lower mold 2, a lower knockout bar 4 that discharges the forged shaft 37 from the lower mold 2 and a cylinder mechanism that moves the lower knockout bar 4 in the vertical direction ( (Not shown). The lower knockout bar 4 is disposed so as to be movable in the vertical direction at a position corresponding to the hole 21 of the lower mold 2. The lower knockout bar 4 is moved upward by a cylinder mechanism and the shaft forged product 37 (after forging) The forged shaft 37 can be peeled off from the lower die 2 by pushing up the rough land 34).

Further, a mold support mechanism (not shown) is provided on the lower side of the lower mold 2, and the lower mold 2 can be supported on the floor surface or the like by the mold support mechanism.
The upper mold 3 is a punch for reducing the wasteland 34 and is disposed above the lower mold 2, and can approach and separate from the upper side with respect to the wasteland 34 placed in the lower mold 2. The upper die 3 (that is, the punch 3), which is the upper die 3, is lowered, and the waste land 34 is crushed so as to be crushed from above.

The punch 3 has a convex shape facing downward, and includes a shaft portion 3a that fits on the inner peripheral surface side of the wasteland 34, and a funnel-shaped push-out portion 3b that is formed to be connected to the upper portion of the shaft portion 3a. The mold release apparatus 10 mentioned later is provided. In particular, an annular punch ring 11 constituting the mold release device 10 is provided around the extruding part 3b so as to surround the outer surface of the extruding part 3b.
The extruded portion 3b is a substantially columnar member, and a cylindrical body surface having a substantially constant diameter is formed on the upper outer surface thereof, and the lower outer surface expands toward the upper portion. A tapered conical surface that is enlarged in diameter and continuous with the body surface is formed. The conical surface is standing upright with respect to the axial center of the punch 2. Specifically, the inclination angle θ formed between the cone surface and the axis of the punch 3 is set to a wide angle of, for example, 45 ° or more with respect to the axis of the punch 3, and the cone surface is outside as viewed from the side of FIG. It has a shape (convex shape) projecting over the surface.

  By forming the conical surface in such a tapered shape, the load component for pushing down the wasteland 34 charged in the lower mold 2 can be increased, so that forward extrusion forging can easily proceed. Further, the tapered conical surface reduces the load component that presses the wasteland 34 in the lateral direction. As a result, the friction generated between the wasteland 34, the lower mold 2 and the punch (upper mold) 3 is reduced, and the shaft forged product 37 can be molded with a small load.

The lower mold 2 and the punch 3 of this embodiment are made using SKT4 or SKT61 (hot forging steel).
Although details of the mold release device 10 will be described later, an outline of the configuration of the punch ring 11 of the mold release device 10 will be described here.
The punch ring 11 is an annular member that surrounds the upper surface of the extruded portion 3b of the punch 3 and has an inner peripheral surface that forms an inner diameter slightly larger than the outer diameter of the extruded portion 3b. 2 It has an outer peripheral surface that forms a slightly smaller outer diameter (substantially the same as the outer diameter of the wasteland) compared to the opening diameter of the upper flange hole. As a result, the punch ring 11 is in a state in which the inner peripheral surface thereof is substantially in contact with the body surface of the extruded portion 3 b of the punch 3.

  The punch ring 11 having the above-described configuration can move (slide) in a predetermined range in the vertical direction on the body surface of the pushing portion 3 b along the axial center direction of the punch 3. When the punch ring 11 slides to an upper upper limit position (upper limit position) within a predetermined range, the size of the punch 3 protruding below the punch ring 11 becomes a size suitable for forging of the shaft forged product 37. As described above, the slide amount and the length along the axial direction of the punch 3 are determined. The structure of the punch ring 11 and the mold release apparatus 10 having the punch line 11 will be described in detail later.

The front / rear extrusion forging apparatus 1 presses the upper part of the waste land 34 inserted into the lower mold 2 from above by a punch (upper mold) 3 integrated with the mold release apparatus 10 having the punch ring 11. .
With continued reference to FIG. 1, the lubricant application process and hollow shaft forging shown in FIGS. 1 (e) to 1 (f) using the above-described front / rear extrusion forging device (hot extrusion forging device) 1 and wasteland 34. The process (main forging process) will be described.

  First, referring to FIG. 1 (e), a wasteland 34 (a wasteland whose center is vertically penetrated) obtained through the hollow forging process and the drilling process is applied to the lubricant application process shown in FIG. 1 (e). Then, a glass lubricant 35 such as a liquid glass lubricant or a powder glass lubricant is applied. This lubricant application step is performed as a preparation for the hollow shaft forging step shown in FIG. 1 (f), and the surface of the wasteland 34 (difficult-to-work material such as titanium alloy) is coated with a glass lubricant 35. Thus, the occurrence of seizure between the mold and the wasteland 34 during forging is suppressed, and the lubricity between the mold and the wasteland 34 is enhanced during forging. Moreover, the mold release property at the time of peeling off the shaft forged product 37 from the mold after forging is also improved.

The waste land 34 that has finished the lubricant application process is sent to the hollow shaft forging process of the next process.
The hollow shaft forging process is a process in which after the forging is performed in the hollow forging process, the rough portion 34 in which the bottom portion is removed and the lubricant 35 is applied in the drilling process is formed into a hollow and funnel-shaped shaft forging 37. is there.
In the hollow shaft forging step shown in FIG. 1 (f), the punch (upper die) 3 and the lower die 2 are heated to a predetermined temperature in advance, and the waste land 34 coated with the glass lubricant 35 is heated. The funnel-shaped recess 22 of the lower mold 2 is inserted and fixed so that the bottom of the inserted rough ground 34 is fitted into the funnel-shaped recess 22. Thereafter, a convex punch (upper die) 3 facing downward is pressed against the central portion of the wasteland 34 fixed to the funnel-shaped concave portion 22 to perform front-rear extrusion forging.

  In front-rear extrusion forging, the waste land 34 is simultaneously pushed forward (downward) and rearward (upward) by the punch 3. Furthermore, the wasteland 34 is pushed out by the further reduction of the punch 3 so that the whole wasteland 34 slides below the lower mold 2, that is, along the funnel shape of the recess 22. As the wasteland 34 is deformed in this way, a hollow and funnel-shaped shaft forging 37 is obtained.

  At this time, as shown in the lower part of FIG. 1 (f), when the deformation of the wasteland 34 proceeds and the punch 3 enters the lower mold 2 deeply, the punch ring 11 provided on the outer periphery of the punch 3 that is the upper mold. And the upper surface of the wasteland 34 are in contact with each other. The punch 3 further enters the lower mold 2 by further pressing, but the punch ring 11 that has come into contact with the wasteland 34 is pushed by the contacted wasteland 34 and slides upward. The punch ring 11 that has been slid to the upper limit position lowers the wasteland 34 together with the punch 3.

  As described above, the size of the punch 3 becomes a size suitable for forging the shaft forged product 37 when the punch ring 11 slides to the upper limit position. That is, the conventional upper mold configuration has a member corresponding to the punch ring formed at the upper limit position around the punch. On the other hand, since the punch ring 11 according to the present embodiment is positioned below the upper limit position for a while after being in contact with the wasteland 34, it can contact the wasteland 34 earlier than the conventional upper mold. Early contact with the wasteland 34 promotes cooling of the upper part of the wasteland 34, and the generation of burrs between the punch ring 11 and the lower mold 2 can be suppressed in the upper part of the wasteland 34. 34 can be smoothly pushed forward.

The forged shaft 37 thus forged is discharged so as to be peeled off from the lower die 2 by the lower knockout bar 4 provided below the lower die 2 (hole 21) (not shown). ).
However, even if the shaft forged product 37 can be released from the lower mold 2 by the lower knockout bar 4, the shaft forged product 37 may be in close contact with the punch 3 that is the upper mold. In particular, in the case of a long hollow forged product such as the hollow shaft forged product 37 described above, the hollow shaft forged product 37 that has shrunk as the temperature decreases as the punch 3 penetrates deeply into the hollow portion, and comes into close contact with the punch 3. Resulting in. This is a state in which the hollow shaft forged product 37 is shrink-fitted to the punch 3, and the punch 3 and the hollow shaft forged product 37 are in very close contact with each other.

As described above, when the hollow shaft forged product 37 is in close contact with the punch 3, a force is applied to push down the punch ring 11 at the upper limit position. If the punch ring 11 is pushed downward, the hollow shaft forged product 37 in close contact with the punch 3 can be released without being damaged.
With reference to FIGS. 2-6, the structure of the mold release apparatus 10 which has the punch 3 and the above-mentioned punch ring 11 is demonstrated in detail.

  FIG. 2 shows an exploded view of the punch 3 and the release device 10 of the front / rear extrusion forging device 1 according to the present embodiment. 2 (a) to 2 (e) are side views of the punch 3 and the release device 10 as viewed from the side. FIGS. 2 (a ') to 2 (e') FIG. 3 is a top view of the mold release device 10 as viewed from above. FIG. 3 shows a state before forging of the front / rear extrusion forging device 1 according to the present embodiment. FIG. 4 shows a state during forging of the front / rear extrusion forging device 1 according to the present embodiment. FIG. 5 shows a state after forging by the front / rear extrusion forging device 1 according to the present embodiment and before release. FIG. 6 shows a state after mold release after forging by the front / rear extrusion forging device 1 according to the present embodiment.

As shown in FIG. 2, the release device 10 includes a punch ring 11, a stepped portion 12 formed on the punch 3, an upper mold attachment plate 13, an upper knockout bar 14, an upper mold plate 15, and an upper cylinder (pressing cylinder). 5
Referring to FIG. 2 (a), the punch 3 is a convex member facing downward as described above. The punch 3 is fitted on the inner peripheral surface side of the waste land 34, and the upper portion of the shaft 3a. It has a funnel-shaped extruding portion 3b formed in a connected manner. The punch 3 is a notch that is notched in a concave shape so that the upper side of the pushing portion 3b on the opposite side (base end side) to the distal end side shaft portion 3a has a smaller diameter (smaller diameter) than the diameter of the pushing portion 3b. As shown, the step portion 12 is set back from the outer peripheral surface of the pushing portion 3b in the axial direction of the punch 3.

  As shown in the top view of FIG. 2 (a ′), the stepped portion 12 is composed of two or more grooves facing in the vertical direction, and is formed at regular intervals along the circumferential direction of the outer peripheral surface of the extruded portion 3b, for example. It is constituted by four concave notches. Each notch has a predetermined length (height) along the axial direction of the punch 3 and is open at the top. In addition, a bolt hole 3 c is formed on the upper surface of the punch 3 so as to be substantially concentric with the axial center of the punch 3.

Referring to FIG. 2B, the punch ring 11 is formed on the annular ring portion 11a surrounding the upper surface of the extruded portion 3b of the punch 3 and the inner peripheral surface of the ring portion 11a as described above. It has a claw portion 11b which is a protrusion, and a support column portion 11c provided on the upper surface of the ring portion 11a.
The ring portion 11 a is a cylindrical (tubular) member having a predetermined thickness, has a predetermined length (height) along the axial direction of the punch 3, and is outside the extrusion portion 3 b of the punch 3. An outer periphery that has an inner peripheral surface that forms an inner diameter that is slightly larger than the diameter, and that has an outer diameter that is slightly smaller than the opening diameter of the flange hole at the upper part of the lower mold 2 (approximately the same diameter as the outer diameter of the rough ground 34). Has a surface.

  The claw portion 11b is located above the inner peripheral surface of the ring portion 11a at a position corresponding to the stepped portion 12 formed of two or more grooves facing the vertical direction formed above the push-out portion 3b of the punch 3. It is provided as a convex protrusion having a shape that meshes with the concave shape of the stepped portion 12. As shown in FIG. 2 (b ′), the claw portion 11b is composed of four convex protrusions formed at equal intervals along the circumferential direction of the inner peripheral surface of the ring portion 11a. The punch ring 11 is attached to the punch 3 by engaging the claw portion 11 b with the step portion 12 of the punch 3.

Since the width and height of the claw portion 11b are slightly smaller than the width and height of the groove of the stepped portion 12, the claw portion 11b can slide up and down along the groove. The ring portion 11a can move (slide) in a predetermined range in the vertical direction on the body surface of the extrusion portion 3b along the axial center direction of the punch 3.
The column portion 11c is, for example, four quadrangular columnar members provided at positions corresponding to the upper portion of the claw portion 11b on the upper surface of the ring portion 11a, and the axial direction of the punch 3 from the upper surface of the ring portion 11a. Is provided so as to extend upward along the ring 11a and is integrated with the ring portion 11a.

In the above description, the step portion 12 is configured by four notches, but may be configured by notches formed over the entire circumference along the circumferential direction of the outer peripheral surface of the extruded portion 3 b of the punch 3. Good. At this time, the claw portion 11 b (projection) of the punch ring 11 may be formed over the entire circumference along the circumferential direction of the inner peripheral surface of the punch ring 11.
Referring to FIG. 2C, the upper mold attachment plate 13 is a square plate material such as a square having a predetermined thickness (thinned) that is smaller than the length of the support column portion 11 c of the punch ring 11. As shown in FIG. 2 (c ′), a bolt hole 13a, which is a through hole corresponding to the bolt hole 3c on the upper surface of the punch 3, is formed at the center of the upper die mounting plate 13, and around the bolt hole 13a. The four pillar holes 13b, which are through holes for allowing the pillar parts 11c to be inserted in a loosely fitted state, are formed at positions corresponding to the four pillar parts 11c of the punch ring 11 attached to the punch 3. Yes.

  Referring to FIG. 2 (d), the upper knockout bar 14 (knockout member) is a quadrangular columnar bar-shaped member that is bridged over four column holes 13 b formed in the upper mold mounting plate 13. Is a cross-shaped member intersecting at almost right angles. As shown in FIG. 2 (d), an upper projection 14a (upper end) is provided at the crossing portion of the cross-shaped upper knockout bar 14, and is projected to each of the four ends of the cross-shaped. Are provided with four lower protrusions 14b (lower end portions) projecting downward corresponding to the four column holes 13b formed in the upper mold attachment plate 13. It can be said that the shape of the upper knockout bar 14 is that two U-shaped (or C-shaped) members intersect each other at right angles with their respective openings facing downward.

Since the upper knockout bar 14 is provided above the upper mold mounting plate 13 with the lower protrusions 14b corresponding to the four column holes 13b formed in the upper mold mounting plate 13, the punching ring protruding from the four column holes 13b 11 can be in contact with the upper surface of the column portion 11c which is the upper end surface of the column 11, and the column portion 11c can be pressed.
Referring to FIG. 2E, the upper mold plate 15 is a member having a predetermined thickness larger than the height (thickness) from the upper protrusion 14a to the lower protrusion 14b of the upper knockout bar 14, and is attached to the upper mold. It is a flat plate material such as a quadrangle substantially the same as or slightly larger than the plate 13. An accommodating space 15a that can be accommodated so as to cover the upper knockout bar 14 from above is formed at a substantially central portion of the lower surface of the upper mold plate 15 by reducing the thickness in the thickness direction.

  The upper mold plate 15 can accommodate the upper knockout bar 14 provided above the upper mold attachment plate 13 in the accommodation space 15 a from above the upper mold attachment plate 13. The accommodating space 15a has a shape and a size that allow only the vertical movement of the upper knockout bar 14 with almost no horizontal movement, and corresponds to the upper protrusion 14a of the upper knockout bar 14. A through hole 15b into which the upper protrusion 14a is fitted is formed at a position where the upper protrusion 14a is fitted.

At this time, the depth of the accommodating space 15a along the thickness direction of the upper mold plate 15 is substantially the same as or slightly deeper than the height from the upper protrusion 14a to the lower protrusion 14b of the upper knockout bar 14, and the accommodating space 15a The entire bar 14 can be completely accommodated.
The upper cylinder 5 is a cylinder having a cylinder shaft 5a which is a rod-shaped member that comes into contact with the upper protrusion 14a (upper end portion) of the upper knockout rod 14 fitted in the through hole 15b of the upper mold plate 15 and presses downward. Mechanism. The upper cylinder 5 is provided at the uppermost position of the front / rear extrusion forging device 1 and moves the cylinder shaft 5a downward to push the upper knockout bar 14 downward and push the punch ring 11 downward. In the drawings referred to in the present embodiment, only the cylinder shaft 5a is shown, and other members and mechanisms constituting the upper cylinder 5 are not shown.

The punch 3, the punch ring 11, the upper mold attaching plate 13, the upper knockout bar 14, the upper mold plate 15, and the upper cylinder 5 shown in an exploded state in FIG. 2 are assembled as follows.
First, the nail | claw part 11b of the punch ring 11 is engaged with the level | step-difference part 12 of the punch 3, and the punch ring 11 is mounted | worn to the punch 3, and the support | pillar part 11c of the punch ring 11 mounted to the punch 3 is attached to the upper mold | type attachment plate. It penetrates through the column holes 13b formed around the 13 bolt holes 13a. Then, a bolt screwed into the bolt hole 13a from above the upper die mounting plate 13 is also screwed into a bolt hole 3c formed on the upper surface of the punch 3, and the upper die mounting plate 13 and the punch 3 are fastened. To do. As a result, the upper side of the stepped portion 12 of the punch 3 that is opened is closed by the upper mold mounting plate 13, and the punching ring 11 has a claw portion 11 b that extends vertically within the range of the height of the stepped portion 12 of the punch 3. It can be moved up and down. When the punch ring 11 rises (slides) to the upper upper limit position (upper limit position) within the height range of the stepped portion 12, the support column portion 11 c of the punch ring 11 is positioned above the upper surface of the upper die mounting plate 13. When it protrudes and descends (slides) to a lower lower limit position (lower limit position) within the range, the support column portion 11c of the punch ring 11 is positioned below the upper surface of the upper die mounting plate 13.

  Next, the upper knockout bar 14 is accommodated in the accommodation space 15 a of the upper mold plate 15. Then, the upper mold plate 15 is mounted so that the lower protrusion 14b of the upper knockout bar 14 in which the upper mold plate 15 is accommodated is disposed at the position of the column hole 13b of the upper mold mounting plate 13 assembled with the punch 3 first. The upper mold plate 15 and the upper mold mounting plate 13 are fastened so as to be integrated with each other by using bolts or the like.

  As shown in FIG. 3, the punch 3, the punch ring 11, the upper mold attaching plate 13, the upper knockout bar 14, and the upper mold plate 15 that are assembled and integrated as described above are arranged with the front end of the punch 3 facing downward. And placed above the lower mold 2. Then, the upper cylinder 5 is disposed above the upper mold plate 15 so that the cylinder shaft 5 a stands upright on the upper protrusion 14 a of the upper knockout bar 14.

  With the arrangement of the upper cylinder 5, the upper knockout bar 14 (knockout member) is arranged between the upper cylinder 5 (pressing cylinder) and the punch ring 11, and the upper protrusion 14a which is the upper end portion of the upper knockout bar 14 has an upper cylinder. 5, and the lower protrusion 14 b which is the lower end portion of the upper knockout bar 14 comes into contact with the upper end surface of the support column portion 11 c of the punch ring 11.

By the above procedure, the punch 3 and the release device 10 as shown in FIG. 3 can be obtained.
Finally, the operation of the mold release apparatus 10 according to the present embodiment will be described with reference to FIGS. 3 to 6, the punching ring of the release device 10 is surrounded by a circle (◯) and shown as an enlarged view.

FIG. 3 shows the state of the front / rear extrusion forging device 1 and the wasteland 34 before forging the hollow shaft forged product 37. The punch 3 (upper mold) integrated with the mold release device 10 is lifted away from the lower mold 2, and the lower mold 2 is loaded with a rough ground 34. At this time, in the mold release device 10, the punch ring 11 and the upper knockout bar 14 are in the lower limit position in the lifting range.
Following the state shown in FIG. 3, the state shown in FIG. 4 is reached. FIG. 4 shows a state of the front / rear extrusion forging device 1 during forging of the hollow shaft forged product 37. The wasteland 34 is being crushed by the punch 3 and the punch ring 11 which are upper molds, and is being formed into a forged product deformed between the lower mold 2. At this time, in the mold release device 10, the punch ring 11 and the upper knockout bar 14 are pushed up to the upper end of the forged product in which the waste land 34 is deformed and are in the upper limit position in the lifting range, and the upward movement is restricted. The ring 11 reduces the forged product from the upper surface.

  Following the state shown in FIG. 4, the state shown in FIG. 5 is obtained. FIG. 5 shows a state of the front / rear extrusion forging device 1 after forging the hollow shaft forged product 37. The forged shaft forged product 37 is released from the lower mold 2 by raising the lower knockout bar 4, but is in close contact with the punch 3 that is the upper mold and lifted upward together with the punch 3. At this time, the punch 3 rises to a position where the cylinder shaft 5 a of the upper cylinder 5 of the release device 10 contacts the upper knockout bar 14 exposed on the upper surface side of the upper mold plate 15.

  Following the state shown in FIG. 5, the state shown in FIG. 6 is obtained. FIG. 6 shows the state of the front / rear extrusion forging device 1 after the hollow shaft forged product 37 is released from the punch 3 which is the upper die. When the cylinder shaft 5a of the upper cylinder 5 is lowered and the upper knockout rod 14 in contact therewith is pushed down, the upper knockout rod 14 pushes down the punch ring 11. The pushed-down punch ring 11 pushes the hollow shaft forged product 37 downward toward the distal end side of the punch 3, thereby peeling the hollow shaft forged product 37 from the punch 3. The hollow shaft forged product 37 is taken out from the front-rear extrusion forging device 1 by the operation of the mold release device 10 shown in FIG.

  In summary, in the mold release device 10 according to the present embodiment, the punch 3, the upper mold mounting plate 13, and the upper mold plate 15 are integrally assembled and fixed by the bolt 3 or the like. As shown in the enlarged view, the punch ring 11 is moved up and down (sliding) along the column hole 13 b of the upper die mounting plate 13 in the movable range (lifting range) of the claw portion 11 b in the step portion 12 formed in the punch 3. Is possible. A lower protrusion 14b of the upper knockout bar 14 is in contact with the support pillar portion 11c of the punch ring 11, and the punch ring 11 moves up and down together with the punch ring 11.

  When the punch ring 11 rises and slides to the upper limit position of the lifting / lowering range, the upper knockout bar 14 pushed up and lifted by the punch ring 11 also slides to the upper limit position in the storage space 15 a of the upper mold plate 15. When the upper knockout bar 14 is raised, the upper protrusion 14a of the upper knockout bar 14 is fitted into the through hole 15b formed in the storage space 15a, and the upper protrusion 14a of the upper knockout bar 14 is exposed on the upper surface side of the upper mold plate 15. . When the exposed upper protrusion 14a is pushed downward, the upper knockout bar 14 is pushed downward and the punch ring 11 is also pushed downward.

  Thus, since the punching ring 11 that can be raised and lowered by the mold release device 10 can be obtained, the punching ring 11 can contact the wasteland 34 earlier than the conventional upper mold to promote the cooling of the upper part of the wasteland 34. As a result, it is possible to suppress the generation of burrs between the punch ring 11 and the lower mold 2 at the upper part of the wasteland 34, so that the forward extrusion of the wasteland 34 by the punch 3 can be made smooth. Moreover, the mold release apparatus 10 according to the present embodiment uses the punching ring 11 that can be moved up and down, so that even if the forged product 37 of the hollow shaft is in close contact with the upper mold 3 and the mold release becomes difficult, the forged product is removed. This produces an effect that the mold can be surely released without being damaged.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. In the embodiment disclosed herein, matters that are not explicitly disclosed, such as operating conditions and operating conditions, various parameters, dimensions, weights, volumes, and the like of the constituents, depart from the scope normally practiced by those skilled in the art. Instead, values that can be easily assumed by those skilled in the art are employed.

For example, in the above-described embodiment, the punch 3 has the step portion 12 and the punch ring 11 has the claw portion 11b. However, as shown in FIG. 7, the punch 3 may have a claw portion 11 b and the punch ring 11 may have a step portion 12.
In the above-described embodiment, as shown in FIG. 2, the upper mold mounting plate 13 has four column holes 13 b at four positions at a pitch of approximately 90 ° corresponding to the four column parts 11 c of the punch ring 11. The upper knockout bar 14 is provided with four lower protrusions 14b corresponding to the four column portions 11c and the four column holes 13b. However, the upper mold attaching plate 13 is not limited to four pillar holes 13b, and any number of pillar holes 13b can be provided at any position such as two or three. Therefore, the upper mold mounting plate 13 may be provided with two support holes 13b at two positions at a pitch of approximately 180 °, or may be provided with three support holes 13b at three positions with a pitch of approximately 120 °. Also in this case, the support 11c of the punch ring 11 and the lower protrusion 14b of the upper knockout bar 14 are provided so as to correspond to the number and positions of the support holes 13b of the upper mold attachment plate 13.

1 Front / rear extrusion forging equipment (hot extrusion forging equipment)
2 Lower mold 3 Upper mold (punch)
3a Shaft portion 3b Extruding portion 3c Bolt hole 4 Lower knockout rod 5 Upper cylinder 5a Cylinder shaft 10 Mold release device 11 Punch ring 11a Ring portion 11b Claw portion 11c Strut portion 12 Step portion 13 Upper mold mounting plate 13a Bolt hole 13b Strut hole 14 Upper knockout bar 14a Upper protrusion 14b Lower protrusion 15 Upper mold plate 15a Housing space 15b Through hole 21 Hole 22 Recess 23 Conical surface 30 Billet (large diameter billet)
31 Elongated billet 32 Short billet 33 Rectangular billet 34 Work material (waste ground)
35 Glass lubricant (lubricant)
37 Hollow shaft forged products (shaft forged products)

Claims (2)

A hollow shaft forged product is manufactured by front-rear extrusion forging by pressing a convex punch, which is an upper die, against a workpiece that is concavely opened upward and is inserted into a lower die. A mold release device for hollow shaft forgings provided in a front-rear extrusion forging device,
A step portion having a small diameter formed on the outer peripheral surface of the base end side of the convex punch;
A ring member provided on the outer peripheral surface of the punch and having a claw portion corresponding to the stepped portion, the claw portion being engaged with the stepped portion and being vertically movable;
A pressing cylinder disposed above the ring member and for pushing the ring member downward;
A knockout member that is disposed between the pressing cylinder and the ring member, an upper end portion of which is in contact with the pressing cylinder, a lower end portion of which is in contact with an upper end surface of the ring member, and pushes out the ring member;
A mold release device for a hollow shaft forged product characterized by comprising: The said level | step-difference part is comprised by the 2 or more groove | channel which faces an up-down direction, The mold release apparatus of the hollow shaft forge product of Claim 1 characterized by the above-mentioned.