JPH09263803A - Molding device for green compact of helical gear and mold adjusting jig - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to maintain a specific relation between external teeth and a rod even after the top end face of a lower punch is polished. SOLUTION: The upper punch 12 and lower punch 13 of the molding device having a die 11, the lower punch 12 and the upper punch 13 for molding the green compact of a helical gear having a positioning hole to maintain a specified relation in the circumference direction with the external teeth are respectively composed of outer rings 12A, 13A having the external teeth 16, 17 and inner rings 12B, 13B fitted relatively rotatably to the inner peripheries thereof. The inner ring 12B of the lower punch 12 is provided with a rod 26 for constituting the positioning hole. The inner ring 13B of the upper punch 13 is provided with an insertion hole 28 into which the rod 26 advances at the time of molding. The lower punch 12 is fixed and the green compact is molded by rotating and lowering the die 11 and lowering the upper punch 13. At this time, the inner ring 13B of the upper punch 13 is so fixed as not to rotate and the outer ring 13A is made rotatable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding apparatus for molding a green compact of a helical gear and a mold adjusting jig for aligning the molding die when the helical gear is manufactured by a powder metallurgy method.

[0002]

2. Description of the Related Art FIG. 5 shows a green compact of a helical gear to be molded here (here, the helical gear of the final product has the same shape, so this is treated as the helical gear 1 here). This helical gear 1 has external teeth (lotus teeth) 2 on the outer peripheral surface of a ring-shaped main body 1A, and on the main body 1A,
It has a positioning hole 5 having a fixed circumferential relationship with the central hole 3 and the outer teeth 2. The positioning hole 5 is
The spiral outer tooth 2 has a certain angle with respect to, for example, a tooth bottom or a tooth tip, and is formed parallel to the center hole 3.

FIG. 6 shows a schematic structure of a conventional molding apparatus for molding such a helical gear 1. This forming apparatus includes a lower punch 12, a die 11 that is fitted on the lower punch 12 to accommodate metal powder inside, an upper punch 13 that fits inside the die 11, and an upper end surface of the lower punch 12. To the upper punch 13 side, the central core rod 25 and the positioning core rod 2 which are attached so as to form the central hole 3 and the positioning hole 5 of the helical gear 1 shown in FIG.
6 is provided.

An inner die 15 for forming the outer teeth 2 (see FIG. 5) of the helical gear 1 is formed on the inner peripheral surface of the die 11. Outer teeth 16 that mesh with the inner die 15 are formed on the outer peripheral surface of the lower punch 12, and the die 11 can be moved up and down with respect to the lower punch 12 by rotating the die 11. The inner die 1 is also attached to the outer peripheral surface of the upper punch 13.
Outer teeth 17 that mesh with the upper punch 13 are formed.
It is possible to form the cavity 19 for compression-molding the metal powder 20 by moving the lower part and engaging with the inner mold 15.

Further, the central core rod 25 has a lower punch 1
It penetrates through the second insertion hole 21 and enters the insertion hole 27 of the upper punch 13 at the time of molding. Further, the positioning core rod 26 is
It penetrates the insertion hole 22 of the lower punch 12 and enters the insertion hole 28 of the upper punch 13 at the time of molding.

By the way, the outer peripheral portion of the upper punch 13 must rotate when the outer teeth 17 of the upper punch 13 mesh with the inner die 15 of the die 11. On the other hand, since the positioning core rod 26 enters the insertion hole 28 of the upper punch 13, the inner periphery of the upper punch 13 must be in a circumferentially fixed relationship with the lower punch 12.

Therefore, the upper punch 13 is divided into an outer ring 13A having outer teeth 17 on the outer peripheral side and an inner ring 13B fitted to the inner periphery of the outer ring 13A so as to be rotatable relative to each other.

When molding is performed by this molding apparatus, the die 11 is fitted into the lower punch 12 and the inside of the die 11 is filled with the metal powder 20. Next, the upper punch 13 is lowered to fit the die 11. Then, in this state, the die 11 is rotated to lower the die 11 by meshing with the lower punch 12 while lowering the upper punch 13 more quickly. The metal powder 20 of 1 is compression-molded to obtain the helical gear 1 of FIG.

[0009]

In this case, the lower punch 12 and the upper punch 1 are applied to the metal powder 20 in the die 11.
3 performs a compression action while rotating relatively. Therefore, the contact surface with the metal powder 20, that is, the lower end surface of the upper punch 13 and the upper end surface of the lower punch 13 may be greatly worn.
As the wear progresses, the molding accuracy is lowered, and therefore the worn surface must be polished and regenerated.

However, although there is no problem with the upper punch 13, when the upper end surface of the lower punch 12 is polished, the relationship between the positioning rod 26 and the outer teeth 16 is displaced.

This point will be described with reference to FIG. Figure 7
(A) shows the upper end of the lower punch 12. The two-dot chain line shows the initial shape of the upper end surface, and the solid line shows the shape of the newly regenerated upper end surface. Since the outer teeth 16 have a spiral shape, when the upper end surface is polished, the position of the outer teeth 16 on the newly regenerated upper end surface and the position of the positioning rod 26 (shown here as the insertion hole 22) are , As shown in FIG. 7B, it is displaced from the initial relationship in the circumferential direction by, for example, an angle δ. If the relationship between the outer teeth 16 and the positioning rod 26 is deviated, the relationship is directly reflected in the helical gear, which is a molded product, and the precision of the molded product deteriorates.

In consideration of the above circumstances, the present invention is an apparatus for molding a powder compact of a helical gear, which can keep the relationship between the external teeth and the rod constant even after polishing the upper end surface of the lower punch having the positioning core rod. The purpose is to provide.
Another object of the present invention is to provide a mold adjusting jig for aligning the outer teeth and the positioning core rod so that the relationship between them is kept constant after polishing.

[0013]

According to a first aspect of the present invention, a ring-shaped main body has outer teeth on its outer peripheral surface and is positioned on the main body so as to have a constant circumferential relationship with the outer teeth. A helical gear green compact having holes is formed, and a die having an inner die for forming outer teeth of the helical gear, and an upper punch and a lower punch having outer teeth meshing with the inner die are provided. In the molding device for compressing and molding the green compact of the helical gear by filling the inside of the with metal powder and fitting the upper punch and the lower punch to the die,
The upper punch and the lower punch each include an outer ring having external teeth and an inner ring fitted to the inner circumference of the lower ring so as to be rotatable relative to each other, and the positioning hole is formed in the inner ring of the lower punch. In addition, the inner ring of the upper punch is provided with an insertion hole into which the rod is inserted at the time of molding, a fixed body for supporting the lower punch, an elevating body for elevating the upper punch with respect to the lower punch, and a lower punch. The inner ring of the inner punch and the inner ring of the upper punch are fixed to the fixed body and the lifting body, respectively, and the inner ring of the upper punch and the outer ring of the lower punch are connected to the inner ring. Rotate the outer ring of the upper punch and the lower outer ring clamp that is fixed to the fixed body in the state of being aligned in the circumferential direction. It said upper outer ring rotation supporting mechanism for supporting the elevating member, as well as rotatably supporting the die, characterized by providing a die support mechanism for vertically moving the die relative to the lower punch in.

According to a second aspect of the present invention, there is provided a die adjusting jig for circumferentially aligning an outer ring of the lower punch with an inner ring having the rod, the upper wall portion being included in the die adjusting jig.
A cup shape having a peripheral wall portion projecting to the lower surface side is formed, and a lower surface of the upper wall portion is provided with an abutting surface that abuts an upper end surface of the outer ring of the lower punch, and an inner periphery of the peripheral wall portion is provided. Inner teeth that mesh with outer teeth of the outer ring are provided, and an insertion hole into which the rod fits is provided in the upper wall portion.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. First, the molding apparatus will be described with reference to FIGS. 1 and 2. FIG. 1 is a sectional view of a main part of a molding apparatus. In the figure, 11 is a die, 12 is a lower punch, and 13 is an upper punch. The lower punch 12 is fixed to a base (fixed body) 50, a portion of which is shown, with its tip end facing upward. The lower punch 12 is composed of an outer ring 12A having outer teeth 16 similar to the helical gear to be molded on the outer peripheral surface of the tip portion, and an inner ring 12B fitted to the inner circumference of the outer ring 12A so as to be relatively rotatable. It is configured. The outer ring 12A and the inner ring 12B that form the lower punch 12 are clamped to the base 50 in a state of being aligned with each other in the circumferential direction. In FIG. 1, only the clamp (lower outer ring clamp) 52 for fixing the outer ring 12A is shown, and the clamp (lower inner ring clamp) for fixing the inner ring 12B is not shown.

At the center of the inner ring 12B of the lower punch 12, there is provided an insertion hole 21 penetrating in the axial direction.
The center hole 3 of the helical gear 1 (see FIG.
A central core rod 25 which forms the
Further, the inner ring 12B is provided with an insertion hole 22 parallel to the central insertion hole 21, and the insertion core 22 has a positioning core rod 26 forming the positioning hole 5 (see FIG. 5) of the helical gear 1. Penetrates. These rods 25 and 26 are slidable in the vertical direction with respect to the lower punch 12, and can be vertically moved by a slide mechanism (not shown).

A die 11 is fitted and arranged on the outer periphery of the upper end of the lower punch 12. An inner die 15 is formed on the die 11, and the inner die 15 is engaged with the outer teeth 16 of the lower punch 12. The die 11 is supported by a vertically movable movable base 53 and a bearing 54, which constitute a die support mechanism, so as to be vertically movable and horizontally rotatable. Therefore, when the die 11 is rotated in the horizontal direction while being fitted to the lower punch 12, the die 11 moves vertically with respect to the lower punch 12.

Above the lower punch 12 and the die 11,
The upper punch 13 is arranged with its axis aligned with the axis of the lower punch 12 and its tip end facing downward. The upper punch 13 is supported by a vertically movable lifting body 60 that constitutes an upper punch support mechanism. The lift 60 is moved up and down by a drive mechanism (not shown). In addition, the upper punch 13 also has the same outer ring 13A as the lower punch 12.
And inner ring 13B. And
The inner ring 13B clamps the clamp 6 to the lifting body 60.
1, the outer ring 13A is fixed by a clamp 65 to a rotating portion 62 that constitutes an upper outer ring rotation support mechanism, and is rotatably supported by a lifting body 60 via a bearing 64.

The inner ring 13B of the upper punch 13
At the time of molding, the insertion hole 27 into which the central core rod 25 enters and the insertion hole 28 into which the positioning core rod 26 enters
Are formed.

FIG. 2 shows the relationship between the die 11, the lower punch 12 and the upper punch 13 in an exaggerated manner when viewed obliquely. In this figure, the die 11 and the lower punch 12 are shown as viewed obliquely from above, and the upper punch 13 is shown as viewed obliquely from below. Upper and lower inner rings 12B, 1
In 3B, since the positions in the circumferential direction must correspond to each other, after fixing the lower punch 12, the upper punch 13 is fixed.
The inner ring 13B of is fixed. Also, the upper punch 13
The outer ring 13A must be fitted to the inner mold 15 of the die 11 as it descends, and is therefore aligned so that it fits exactly.

The procedure for forming with this forming apparatus is the same as that described above. The lower punch 12 is fitted with the die 11, the inside of the die 11 is filled with the metal powder 20, and then the upper punch 13 is formed. It is lowered and fitted to the die 11. Then, in this state, the upper punch 13 is lowered while rotating and lowering the die 11, whereby the metal powder is compression-molded by the lower punch 12 and the upper punch 13.

When the lower end surface of the upper punch 13 and the upper end surface of the lower punch 12 are worn by the molding, the surfaces are polished. Then, the positional deviation of the outer ring 12A and the inner ring 12B in the circumferential direction, which is particularly problematic on the side of the lower punch 12 serving as a reference, was corrected by using a jig, and the positions of the outer ring 12A and the inner ring 12B were adjusted correctly. The above is fixed to the base of the molding apparatus. Since the outer ring 13A is rotatable with respect to the inner ring 13B on the upper punch 13 side, there is no particular problem by adjusting the rotational position.

Next, the outer ring 12A of the lower punch 12
A jig for aligning the inner ring 12B (die adjustment jig) and an adjustment method using the jig will be described. FIG. 3 shows the outer ring 12A and the inner ring 1 by the jig 70.
2B shows a state in which 2B is aligned in the circumferential direction. Also,
FIG. 4 shows the structure of the jig 70.

The jig 70 has a cup shape having an upper wall portion 71 and a peripheral wall portion 72 projecting from the lower surface side thereof. The upper wall portion 71 and the peripheral wall portion 72 are machined as separate pieces, as shown in FIGS. 4C and 4D, and are integrated by being connected to each other by bolts 73. The lower surface of the upper wall portion 71 is a contact surface 75 with which the upper end surface of the outer ring 12A of the lower punch 12 abuts, and the inner periphery of the peripheral wall portion 72 meshes with the outer teeth 16 of the outer ring 12A. Internal teeth 76 are provided. Further, the upper wall portion 71 is provided with an insertion hole 77 through which the central core rod 25 is inserted and an insertion hole 78 through which the positioning core rod 26 is inserted. In addition, 79a and 79b are the upper wall part 71 and the peripheral wall part 7.
2 is an engaging concave portion and an engaging convex portion for positioning 2 in the circumferential direction.

When the jig 70 is used to align the lower punch 12, the following procedure is performed, for example. First, with the rods 25 and 26 retracted, the jig 70 is covered on the lower punch 12, and the contact surface 75 on the lower surface of the jig 70 is covered.
Is brought into contact with the upper end surface of the outer ring 12A,
The inner teeth 76 of the jig 70 are replaced by the outer teeth 16 of the outer ring 12A.
Mesh with. Then, in this state, while rotating the jig 70 and the outer ring 12A, the insertion hole 78 of the jig 70 and the insertion hole 22 of the lower punch 12 are aligned, and when they are aligned, the positioning core rod 26 is projected upward. This rod 2
When 6 enters the insertion hole 78 of the jig 70, the outer ring 1
2A does not rotate, and the outer ring 12A and the inner ring 12B are properly aligned. Therefore, in this state, the outer ring 12A is fixed by the clamp on the base.

[0026]

As described above, according to the first aspect of the invention, the lower punch, which is the reference side of molding, is divided into the outer ring and the inner ring, and their positions are adjusted in the circumferential direction. Since it is possible to fix the position, the positional relationship between the alignment core rod and the external teeth can be appropriately corrected even when the upper end surface is polished. Further, by using the die adjusting jig of the invention of claim 2, it becomes possible to easily adjust the positions of the outer ring and the inner ring of the lower punch.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of a molding apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view showing an exaggerated relationship between a die, a lower punch and an upper punch in the embodiment.

FIG. 3 is a cross-sectional view showing a state in which a lower punch of the molding apparatus is aligned by using a mold adjusting jig according to an embodiment of the present invention.

FIG. 4 is a configuration diagram of the mold adjustment jig shown in FIG.
Is a sectional view of the entire jig, FIG. 7B is a bottom view of the same, FIG. 7C is a sectional view of an upper wall portion of the jig, and FIG. 8D is a sectional view of a peripheral wall portion of the jig. In addition, FIG. (A) is IVa-IVa of FIG.
It is arrow sectional drawing.

5A and 5B are configuration diagrams of a helical gear (compacted powder) which is a molding target of the molding apparatus of the present invention, in which (a) is a perspective view and (b) is a plan view.

FIG. 6 is a cross-sectional view showing a schematic configuration of a conventional molding device.

FIG. 7 is a configuration diagram of an upper end portion of a lower punch in a conventional forming apparatus, (a) is a perspective view and (b) is a partial plan view.

[Explanation of symbols]

 1 Helical gear (compacted powder) 1A Main body 2 External tooth 5 Positioning hole 11 Die 12 Lower punch 12A Outer ring 12B Inner ring 13 Upper punch 13A Outer ring 13B Inner ring 15 Inner die 16,17 Outer tooth 20 Metal powder 26 Positioning core rod 28 Insertion hole 50 Base (fixed body) 52 Lower outer ring clamp 53 Moving stand (die support mechanism) 54 Bearing (die support mechanism) 60 Lifting body 61 Upper inner ring clamp 62 Rotating body (upper outer ring rotation support mechanism) 64 Bearing (upper outer ring rotation support mechanism) 70 type adjustment jig 71 upper wall portion 72 peripheral wall portion 75 contact surface 76 internal teeth 78 insertion hole

Claims (2)

[Claims] 1. A green compact of a helical gear having outer teeth on an outer peripheral surface of a ring-shaped main body, and positioning holes having a constant circumferential relationship with the outer teeth on the main body. Equipped with a die having an inner die for forming the outer teeth of the helical gear, and an upper punch and a lower punch having outer teeth meshing with the inner die, the inside of the die is filled with metal powder, and the upper punch is provided. In a molding device for compressing and molding a green compact of a helical gear by fitting the upper punch and the lower punch to a die, the upper punch and the lower punch are respectively provided with an outer ring having outer teeth and an inner ring having outer teeth. The inner ring of the lower punch is provided with a rod that constitutes the positioning hole, and the inner ring of the upper punch is provided with an insertion hole through which the rod enters during molding. In addition, the fixed body that supports the lower punch, the lifting body that raises and lowers the upper punch with respect to the lower punch, the inner ring of the lower punch and the inner ring of the upper punch are associated with each other in the circumferential direction. The lower inner ring clamp and the upper inner ring clamp that are fixed to the fixed body and the lifting body, and the lower outer ring that fixes the outer ring of the lower punch to the fixed body while aligning them in the circumferential direction with respect to the inner ring. A ring clamp, an upper outer ring rotation support mechanism that rotatably supports the outer ring of the upper punch on the lifting body, and a die support mechanism that rotatably supports the die and vertically moves the die with respect to the lower punch. And a helical gear compact forming device. 2. A mold adjusting jig for circumferentially aligning an outer ring of the lower punch with an inner ring having the rod, the upper wall part and a peripheral wall part projecting to a lower surface side thereof. And a contact surface for contacting the upper end surface of the outer ring of the lower punch is provided on the lower surface of the upper wall portion, and an inner surface of the inner wall that meshes with outer teeth of the outer ring. A die adjusting jig, wherein teeth are provided, and an insertion hole into which the rod is fitted is provided in the upper wall portion.