JPH09206999A - Compression molding machine for sintering - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve productivity by providing an elastic member for pressing a floating member in the direction of a ram and a displacement adjusting means for adjusting a space between the floating member and the base, thereby facilitating the adjustment of a pressing force. SOLUTION: With a pressing force applied in the compression molding process of a sintered product, a third lower punch 23 and a floating plate 4 are displaced in the axial direction against a coil spring 7, and supported in contact with the upper face 1U of the base or the upper face 2U of the worm wheel 2. The pressing force of the third lower punch 23 is such that, with a change in the space CL1 , the compression of the coil spring 7 changes and that, therefore, with the rotation of a worm 3, the worm wheel 2 lowers in the axial direction, adjusting the space CL1 . As a result, change in the pressing force incident to the change of molding conditions can be attained through the adjustment of the space CL1 of the floating member, enabling the set-up process to be shortened and the productivity to be improved.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an improvement of a compression molding machine used for sintering.

[0002]

2. Description of the Related Art Conventionally, in the molding of sintered parts, a compression molding machine such as a crank press or a hydraulic press is used to perform compression molding of metal powder, followed by a sintering step. A compression molding machine as shown in FIG. 4 is known.

FIG. 4 shows a compression molding machine for molding a sintered component such as a pulley by using a crank press. The upper ram 10 and the lower ram 20 are relatively displaceable in the axial direction (vertical direction in the drawing). And a die 30 that is also relatively axially displaceable with respect to the upper and lower rams 10 and 20, and the powder filled in the cavity is transferred to the upper and lower rams 10 and 2.
Upper punches 11 to 13 supported by 0 and divided into a plurality of parts
By sandwiching and pressing with the lower punches 21 to 23,
The molded body 8 having a predetermined shape is compression-molded.

Here, a second lower punch 22 and a first lower punch 21 are provided on the lower ram 20 from a cylindrical third lower punch 23 that can be fitted to the inner periphery of the die 30 toward the inner peripheral side. A core 4 that is sequentially supported and forms a shaft hole portion of the molded body 8 on the innermost periphery.
0 and a rod 41 for supporting the same are arranged upward in the figure.

On the other hand, on the upper ram 10, a second upper punch 12 and a first upper punch 11 are sequentially supported on the inner peripheral side from a cylindrical third upper punch 13 which can be fitted to the inner periphery of the die 30. , The first upper punch 11 faces the core 40 of the lower ram 20 and the first lower punch 21, and the second upper punch 12 makes the second lower punch 22.
Then, the third upper punch is arranged to face the third lower punch 23, respectively.

By the way, in the step of taking out the molded body 8 after finishing the pressurization, as shown in FIG. 5, the molded body 8 is taken out after the die 30 is relatively displaced to the lower ram 20 side. The flexural amounts of the multi-divided punches in the axial direction are different from each other. Due to the difference in the flexural amounts, a gap is created between the molded body 8 and the punch, and the molded body 8
Insufficient force is applied when the molded body 8 is pulled out from the die 30, because a sufficient force for holding the molded body 8 is not obtained, and further, when the pressurization is completed, the molded body 8 expands in size due to springback. It is known that the molded body 8 is cracked.

In FIG. 5, the outermost third lower punch 2 is shown.
A gap is generated between the molded body 8 and the molded body 8, and the spring back of the molded body 8 moves toward the outer periphery by the lowering of the die 30,
An example in which the molded body 8 is cracked from the vicinity of the upper end portion of the second lower punch 23 is shown.

Therefore, in order to prevent such cracking of the molded body 8, the punch having the least amount of deflection at the time of pressurization is elastically supported so as to be relatively displaceable with respect to other punches, and the molded body generated at the end of pressurization. By eliminating the gap between the molded body 8 and the molded body 8, cracking of the molded body 8 as described above can be prevented.

Therefore, in FIG. 4, the third upper and lower punches 13 and 23, which have the least amount of deflection at the time of pressurization, are elastically supported so as to be relatively displaceable with respect to the first and second upper and lower punches 11, 12 and 21, 22. doing.

The lower ram 20 will be described below.
The third lower punch 23 is erected on a floating base 92 that is axially displaceable relative to the mounting portion 20A of the lower ram 20, and the floating base 92 and the mounting portion 20A are provided.
An elastic member 93 is disposed between the floating base 92 and the lower ram 20 at a predetermined distance from the axis, and a predetermined gap δ is formed between the floating base 92 and the mounting portion 20A of the lower ram 20.

The floating base 92 has a through hole formed on the outer peripheral side with respect to the position where it abuts on the elastic member 93, and a bolt 95 fastened to the mounting portion 20A through this through hole.
Is inserted into the floating base 92 to restrict the displacement of the floating base 92 upward within a predetermined range, and the bush 94 is interposed between the bolt 95 and the floating base 92.
Thereby guides the floating base 92 along the axial direction.

The upper ram 10 is also constructed in the same manner as the lower ram 20, and the floating base 91 supporting the third upper punch 13 is attached to the upper ram 10 via the elastic member 93.
The floating base 91 is supported so as to be relatively displaceable with respect to A, and is located on the outer peripheral side of the position where it abuts on the elastic member 93.
Is inserted through the bolt 95 fastened to the mounting portion 20A to restrict the downward displacement of the floating base 91 in the figure to a predetermined range, and by the bush 94 interposed between the bolt 95 and the floating base 91. The floating base 91 is guided along the axial direction.

In this way, by elastically supporting the third upper and lower punches 13 and 23, which have the least amount of deflection at the time of pressing, in the step of removing the molded body 8 after completion of pressing, the molded body is urged by the elastic member 93. It is intended to prevent the crack of the compact 8 by eliminating the gap between the upper and lower punches 8 and the upper and lower punches 13 and 23.

[0014]

However, in such a conventional compression molding machine, it is necessary to adjust the urging force of the elastic member 93 when changing the density or pressure of the molded body 8. The member 93 and the bush 94 must be replaced to change the urging force, and in order to carry out this replacement, a punch or the like needs to be attached and detached, which requires a great deal of labor and time in the setup process to improve productivity. In addition to lowering it, it is necessary to readjust the urging force of the replaced elastic member 93 or bush 94, and then readjust, or prepare various elastic members 93 and bush 94 for fine adjustment of the urging force. There was a problem that had to be.

Further, as shown in FIG. 6, the floating base 91 having the third upper and lower punches 13 and 23 attached thereto,
Since the elastic member 93 that supports 92 is located at a position separated from the axis by a predetermined distance R toward the outer peripheral side, when pressure is applied to the third lower punch 23, the floating base 92 is broken by the elastic member 93 as a fulcrum in the drawing. , The through hole of the floating base 92 and the bolt 95 or bush 94.
In some cases, galling occurs between the upper and lower ends, the floating base 92 is not smoothly displaced in the axial direction, and an appropriate biasing force cannot be applied to the third lower punch 23.

Therefore, the present invention has been made in view of the above problems, and can easily and quickly change and adjust the density and pressing force of a molded body to improve productivity and also to occur in a punch supporting member. An object of the present invention is to provide a molding compressor for sintering, which can suppress bending and reliably suppress cracking of a molded body.

[0017]

According to a first aspect of the present invention, a pair of rams facing each other and capable of relative displacement in the axial direction, and a die capable of relative displacement in the axial direction with respect to these rams are provided. A plurality of punches, which are attached to the ram and are formed by compression molding the powder on the inner circumference of the die, and elastic support means, which are disposed on the ram side and elastically support one of the punches. In the compression molding machine for sintering, the elastic supporting means supports one of the punch and the base attached to at least one of the rams, and through a guide means attached to the base. A floating member capable of relative displacement in a predetermined range in the axial direction and capable of forming a predetermined gap with the base; and a flow interposed between the base and the floating member. Comprising an elastic member biasing the axial direction towards the ram which faces the Ingu member, and a displacement amount adjusting means for adjusting the gap between the floating member and the base.

In a second aspect based on the first aspect, the displacement amount adjusting means is screwed with the base and is capable of axially displacing a gap toward a floating member in response to rotation. It comprises a member and a driving means for irreversibly rotating and driving the gap adjusting member.

In a third aspect based on the second aspect, the drive means comprises a worm wheel formed in the gap adjusting member and a worm meshing with the worm wheel.

In a fourth aspect based on the first aspect, the elastic member is arranged at a predetermined position near the axis of the column.

[0021]

Therefore, according to the first aspect of the present invention, the powder filled in the inner periphery of the die is pressed by the punches which are divided into a plurality of pieces and are respectively attached to the pair of rams, whereby the sintered compact is compression-molded. It When removing the compact by displacing the die relatively, one of the multiple punches, for example, the one with the least amount of deflection, is elastically supported to eliminate the gap between the compact and the punch and crack the compact. Can be prevented.

This punch is attached to a floating member which is axially displaceable with respect to the base via a guide member, and is urged toward the molded body by an elastic member between the base and the floating member, so that the amount of displacement of the floating member is increased. A biasing force corresponding to is applied to the punch. This urging force can be changed by adjusting the gap between the floating member and the base, and the urging force of the punch can be adjusted easily and quickly by changing the compression molding conditions.

According to the second aspect of the invention, the displacement amount adjusting means can adjust the gap between the floating member and the base by changing the axial displacement amount by the rotational movement of the gap adjusting member screwed to the base. Since the gap adjusting member is driven irreversibly, the biasing force adjusted by an external force such as vibration applied to the gap adjusting member side does not go wrong.

In the third aspect of the invention, the gap adjusting member is driven by the worm wheel and the worm, and the drive from the worm to the worm wheel can be performed irreversibly.

According to the fourth aspect of the invention, since the elastic member for elastically supporting the floating member is arranged at a predetermined position close to the axis of the column, the bending of the floating member due to the pressure applied during compression molding is suppressed. As a result, galling between the floating member and the guide member can be prevented, and smooth displacement of the floating member can be ensured.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings.

1 to 3, a floating base 92, which is supported by the lower ram 20 shown in the above-mentioned conventional example, and on which a third lower punch 23 is erected, is shown as a base 1, a gap adjusting member (displacement adjusting means). 4) is replaced with a cushion adapter 100 mainly composed of the worm wheel 2 as the above) and the floating plate 4 as the floating member, and the other configurations are similar to those of the conventional example of FIG.

First, as shown in FIG. 1 and FIG. 2, the base 1 formed of a substantially disk-shaped member is inserted into a bolt hole 1D penetratingly formed in a peripheral portion thereof, and a bottom surface 1L side is inserted through a bolt 50. The lower ram 20 toward the mounting portion 20A shown in FIG.
In order to prevent dust, a plate-shaped cover 6 is interposed between the base 1 and the mounting portion 20A.

It is not necessary to dispose the elastic member 93 as shown in FIG. 4 on the mounting portion 20A, and the upper surface of the mounting portion 20A is assumed to be a smooth end surface.

A third lower punch 2 is provided on the upper surface 1U side of the base 1.
A floating plate 4 which stands 3 is attached.

The floating plate 4 is attached to the base 1 so as to be relatively displaceable in the axial direction (vertical direction in FIG. 1) within a predetermined range, and the first and second lower punches 21, 22 and the like are attached thereto. It is formed of a disk-shaped member having a through hole for insertion.

The outer periphery of the floating plate 4 is coupled to the base 1 and is in sliding contact with the inner periphery of an annular clamp ring 5 having a substantially inverted L-shaped cross section as a guide member. In the range of the gap CL between the lower surface and the upper surface 1U of the base 1, the axial relative displacement (stroke, the same applies below) is allowed.

A plurality of recesses 4A for accommodating the coil springs 7 as elastic members are formed at predetermined positions on the lower surface of the floating plate 4 facing the base 1, and the coil springs 7 accommodated in these recesses 4A are The floating plate 4 is interposed between the floating plate 4 and the upper surface 1U of the base 1, and the floating plate 4 is constantly urged upward in the drawing. The coil spring 7 is arranged at a position as close to the axis as possible.

The floating plate 4 is restricted from being displaced upward at a position where the upper surface of the floating plate 4 contacts the lower surface of the inverted L-shaped clamp ring 5, and the maximum displacement amount (maximum stroke) of the floating plate 4 in the axial direction. Is the above gap C
When the third lower punch 23 is in an unloaded state as shown in FIG.
As described above, the floating plate 4 has its upper surface locked by the inverted L-shaped clamp ring 5 to form the maximum clearance CL with the base 1.

The annular clamp ring 5 is fastened to the upper surface 1U of the base 1 via bolts 51.

Then, the third lower punch 23 is fastened to the upper surface of the floating plate 4 through the clamp ring 53 and the bolt 52 so as to be erected upward. The third lower punch 23 faces the third upper punch 13 shown in FIG.

Here, inside the base 1, a worm wheel 2 which is rotatable and axially displaceable, and means for irreversibly driving the worm wheel 2 by meshing with the outer periphery of the worm wheel 2 are engaged. Worm 3 is contained.

As shown in FIGS. 1 and 3, the worm wheel 2 comprises a cylindrical portion and a disc portion, and a disc portion 2D having a gear 2G meshing with the worm 3 formed on the outer periphery thereof.
And a cylindrical portion 2A having a male screw 2B formed on the outer circumference. The worm wheel 2 has a through hole 2C formed along the axis of the third lower punch 23 (hereinafter, simply referred to as the axis), and the first and second lower punches 21 and 22 are formed.
Etc. through the inner circumference. In the figure, the end surface on the side of the cylindrical portion 2A is the upper surface and the end surface on the side of the disk portion 2D is the lower surface. The worm 3 is arranged on a plane orthogonal to the axis.

On the other hand, as a space for accommodating the worm wheel 2 and the worm 3 in the base 1, as shown in FIGS.
The through hole 1C is formed along the axis as shown in FIG.

On the inner circumference of the through hole 1C, a female screw 1B screwed with a male screw 2B formed on the cylindrical portion 2A of the worm wheel 2 is inserted from the upper surface side to a large diameter portion for accommodating the disc portion 2D. 1F is formed on each of the bottom surfaces 1L, and a predetermined step portion 1A is formed between the female screw 1B and the large diameter portion 1F. Further, on the bottom surface 1L side of the base 1, the worm 3
And a groove portion 1E 'for axially supporting a shaft portion (not shown) of the worm 3 are formed. In addition, one end of the shaft portion of the worm 3 has a groove portion 1E ′ shown in FIG.
It is formed rotatably by being protruded from it or manually or by driving means (not shown).

Thus, the worm wheel 2 has the tubular portion 2
Is engaged with the female screw 1B of the base 1 and meshes with the worm 3 at the disc portion 2D, so that the upper surface 2U of the worm wheel 2 expands and contracts in the axial direction from the upper surface 1U of the base 1 according to the rotation of the worm 3. As for the axial displacement of the worm wheel 2, the bottom surface 2L contacts the mounting portion 20A of the lower ram 20 from the position where the bottom surface 2L contacts the upper surface of the disk portion 2D contacts the step portion 1A on the inner circumference of the base 1. The range CL _{2 is set} , and in FIG. 1, the gap CL ₂ between the upper surface of the disc portion 2D and the step portion 1A is set to be substantially equal to the gap CL between the floating plate 4 and the base 1 in the unloaded state, for example.

As shown in FIG. 1, the axial dimension of the worm wheel 2 is set to be approximately equal to the thickness of the base 1 (axial dimension) plus the plate thickness of the cover 6, and the worm wheel 2 Lowest position of wheel 2 (most contracted position)
Then, the upper surface 2U becomes parallel to the upper surface 1U of the base 1, and a predetermined gap CL ₁ is formed between the upper surface 2U of the worm wheel 2 and the lower surface of the floating plate 4, so that the base 1
The clearance CL ₁ with the floating plate 4 increases or decreases as the worm wheel 2 screwed into the female screw 1B is moved up and down.

The operation will be described next.

In the compression molding process of the sintered part, the lower ram 20
When a pressing force is applied to the third lower punch 23 attached to the third lower punch 23 and the floating plate 4,
Is axially displaced downward in FIG. 1 against the urging force of the coil spring 7, and the lower surface of the floating plate 4 is in contact with the upper surface 1U of the base 1 or the upper surface 2U of the worm wheel 2 during pressurization. The molded body 8 in the cavity can be reliably compressed by being contacted and supported.

On the other hand, the urging force applied by the third lower punch 23 to the compact 8 after the pressurization can be generated according to the amount of contraction of the coil spring 7, that is, the upper surface 2U of the worm wheel 2 and the floating. When the gap CL ₁ with the lower surface of the plate 4 is changed, the maximum displacement amount of the floating plate 4 in the axial direction is changed, the contraction amount of the coil spring 7 is changed, and the coil spring 7 is moved to the third position.
The biasing force applied to the lower punch 23 can be finely adjusted.

At the position where the clearance CL ₁ between the upper surface 2U of the worm wheel 2 and the lower surface of the floating plate 4 is maximum, the displacement amount of the floating plate 4 is the upper surface 1U of the base 1 and the lower surface of the floating plate 4 when there is no load. Becomes equal to the clearance CL between the upper ram 10 and
When a pressure (smaller than the pressure at the time of molding) for holding the molded body 8 is applied from the (or lower ram 20) side, the third lower ram 20 is displaced downward in FIG. It is possible to eliminate the gap between the molded body 8 and the third lower punch 23 as shown in (4) to prevent the occurrence of cracks when the molded body 8 is removed.

Depending on the density of the molded body 8 and the change of the pressing force,
The urging force applied to the third lower punch 23 can be adjusted only by rotating the worm 3, and the worm wheel 2 screwed to the base 1 according to the rotation of the worm 3 moves up and down in the axial direction. And floating plate 4
CL ₁ between the lower surface and the upper surface 2U is adjusted.

The maximum displacement amount of the floating plate 4 and the third lower punch 23 is determined according to the change of the clearance CL ₁ , and the biasing force that can be applied by the coil spring 7 depends on this maximum displacement amount. Unlike the conventional example, it is not necessary to remove the punch or replace the elastic member, and the urging force can be easily and quickly adjusted by simply rotating the worm 3, which shortens the setup process. The productivity can be improved, and further, by adjusting the rotation angle of the worm 3 or the like, it is possible to adjust the biasing force, which was not possible in the conventional example, and a wide compression range can be achieved. It is possible to meet molding conditions.

Further, even if an external force such as vibration is applied to the worm wheel 2, the worm 3 is not driven, so that the urging force once set can be maintained, and the worm 3 causes the worm wheel 2 to be irreversible. Therefore, it is possible to prevent the set value of the urging force from being deviated due to the vibration applied to the compression molding machine, and it is possible to improve the reliability.

Further, since the coil spring 7 for elastically supporting the floating plate 4 is arranged at a position as close as possible to the third lower punch 23, the conventional example shown in FIG.
Floating plate 4 during molding and pressurization as shown in
Deflection can be suppressed, galling with the clamp ring 5 can be prevented, smooth relative displacement of the third lower punch 23 can be ensured, and cracking can be reliably prevented in the removal process of the molded body 8. Therefore, the reliability of the compression molding machine can be improved. In addition, although the case where the present invention is applied to the lower ram 20 is shown in the above-described embodiment, although not shown, the same effect can be obtained by applying the present invention to the upper ram 10. Cushion adapter 100 including floating base 91, base 1 and floating plate 4
You can replace it with.

Further, in the above embodiment, the third lower punch 2
Although the case where 3 is elastically supported has been described, it is sufficient to elastically support the punch having the smallest deflection amount among the plurality of punches that are formed in a divided manner, depending on the shape of the molded body 8, the powder, the molding pressure condition, and the like. And applied to the first or second punch.

[0052]

As described above, in the first aspect of the invention, the punch is attached to the floating member which is axially displaceable with respect to the base through the guide member, and the punch is attached by the elastic member between the base and the floating member. The punch is biased toward the compact body, and a biasing force corresponding to the displacement amount of the floating member is applied to the punch. This biasing force can be changed by adjusting the gap between the floating member and the base. The urging force of the punch can be adjusted easily and quickly, and there is no need to remove the punch or replace the elastic member as in the conventional example, and the urging force can be adjusted simply by adjusting the gap of the floating member. Therefore, the setup process can be shortened and the productivity can be improved.

According to the second aspect of the invention, the displacement amount adjusting means can adjust the gap between the floating member and the base by changing the axial displacement amount by the rotational movement of the gap adjusting member screwed on the base. Since the gap adjusting member is driven irreversibly, the biasing force adjusted by the external force such as the vibration applied to the gap adjusting member does not change, and the reliability of the compression molding machine can be improved.

According to the third aspect of the invention, the gap adjusting member is driven by the worm wheel and the worm, the drive from the worm to the worm wheel can be performed irreversibly, and the rotation angle of the worm is adjusted. By doing so, it becomes possible to adjust the biasing force, which was impossible in the conventional example, and it is possible to deal with a wide range of compression molding conditions.

According to the fourth aspect of the invention, since the elastic member for elastically supporting the floating member is arranged at a predetermined position close to the axis of the column, the bending of the floating member due to the pressure applied during compression molding is suppressed. As a result, galling between the floating member and the guide member can be prevented, smooth displacement of the floating member can be ensured, and cracking of the molded body can be reliably prevented.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a cushion adapter showing an embodiment of the present invention.

FIG. 2 also shows a base, (A) is a bottom view,
(B) shows each AA arrow sectional drawing.

FIG. 3 is a sectional view of the worm wheel.

FIG. 4 is a sectional view of a main part of a conventional compression molding machine.

FIG. 5 is an enlarged cross-sectional view of a main part of a compression molding machine showing a state of taking out a molded body.

FIG. 6 is a conceptual diagram showing a state in which a floating plate is bent at the time of pressurization according to a conventional example.

[Explanation of symbols]

 1 Base 1A Step 1B Female Thread 1C Through Portion 1D Through Hole 1E Recess 1F Large Diameter 1L Bottom 1U Upper Surface 2 Worm Wheel 2A Cylindrical 2B Male Screw 2C Through 2D Gear 2L Lower 2U Upper 3 Warm 4 Floating Plate 4A Recess 4C Penetration 5 Clamp ring 6 Cover 7 Coil spring 8 Formed body 10 Upper ram 10A Mounting base 11 First upper punch 12 Second upper punch 13 Third upper punch 20 Lower ram 20A Mounting base 21 First lower punch 22 Second lower Punch 23 Third lower punch 30 Die 40 Core 41 Rod 51, 52 Bolt 53 Clamp ring 91, 92 Floating base 93 Elastic member 94 Bush 95 bolt

Claims (4)

[Claims] 1. A pair of rams facing each other and capable of relative displacement in the axial direction, a die relatively displaceable in the axial direction with respect to these rams, attached to the ram, and inside the die. In a compression molding machine for sintering, which comprises a plurality of punches formed by compression for surrounding powder, and elastic supporting means arranged on the ram side to elastically support one of the punches. The elastic support means supports one of the punch and the base attached to at least one of the rams, and is relatively displaceable in a predetermined range in the axial direction via a guide means attached to the base. And a floating member capable of forming a predetermined gap between the base and the base, and is interposed between the base and the floating member to direct the floating member to an opposing ram. A compression molding machine for sintering, comprising: an elastic member urged in the direction of the beam axis; and a displacement amount adjusting means for adjusting a gap between the floating member and the base. 2. The displacement amount adjusting means is screwed with the base, and is capable of axially displacing toward a floating member in response to rotation, and an irreversibly rotationally driving the gap adjusting member. The compression molding machine for sintering according to claim 1, further comprising: 3. The compression molding machine for sintering according to claim 2, wherein the driving means includes a worm wheel formed in the gap adjusting member and a worm that meshes with the worm wheel. 4. The elastic member is arranged at a predetermined position near the axis of the column.
The compression molding machine for sintering according to.