JP2996070B2 - Sizing equipment for powder molded products - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to resizing (sizing) of a molded article which has been compacted and sintered by a powder compacting press.
The present invention relates to an apparatus for sizing powder molded products.

[0002]

2. Description of the Related Art A so-called sintering machine part is manufactured by sintering a compression-molded product obtained by compressing and molding a powder material by a compression means such as a powder molding press machine by a heating means such as a heating furnace. When the molded product W after sintering (hereinafter, “sintered product”) is further formed into a desired size, usually after the sintering step is completed, the sintered product is subjected to the following process. Sizing process is performed. That is, as shown in FIGS. 11A and 11B, the formed sintered product W is
After being inserted into the die 1, the sintered product W in the die 101 is compressed by the upper punch 103 and the lower punch 105. Thus, a sintered machine component is manufactured by shaping the sintered product W to a desired size.

[0003]

However, when the shape of the sintered product W has an undercut portion U as in a double chain type sprocket 1 shown in FIG.
Problems occur when sizing is performed by the conventional sizing method. That is, as shown in FIG. 12, since there is no member for supporting the undercut portion U of the sintered product W, the upper and lower punches 1
When a compressive force from 03, 105 is applied, an excessive force is applied to the sintered product W, and the component may be damaged.

Further, on the other hand, if supported undercut portion U, the surface facing the undercut portion U Dimensions
Compressive force is not applied to correct, even if subjected to sizing not improved dimensional precision in order to obtain the dimensional accuracy of the request, it is necessary to machine.

[0005] The present invention was made in view of the problems as described above, the sintered machine parts that have a undercut portion, and an object thereof is to provide a sizing device which can be formed into a desired size.

[0006]

Means for Solving the Problems] sizing apparatus of a powder molded article of the present invention for achieving the above object, a side
The axial direction of the powder molded product with an undercut formed on
Holds the end and moves relatively close in the axial direction
A first punch and a second punch which are compressed by
The powder molded product is provided coaxially with the punch,
And are configured to move relatively close to and away from each other.
The first die and the second die, and the
Can be inserted into and removed from the undercut part.
In such a state that it can be raised and lowered together with the powder molded product.
Sizing apparatus for powder molded products having a support punch provided
, The supporting punch is an undercarriage of a powder molded product.
And a proximal end that follows the distal end
And the thickness of the proximal end is thinner than the thickness of the distal end.
And the width of the base end is smaller than the diameter of each of the dies.
The tip of the support punch is under
The first die and the second die are inserted into the cut portion.
When the tool moves close to the base, the base end of the support punch
It is located in the groove provided on the contact surface of each die,
A predetermined gap is formed between the part and each die .

[0007]

According to the present invention having the above-mentioned features, the powder molded product is first held by the first punch and the second punch, and the undercut of the undercut support punch is formed in the undercut portion of the powder molded product. The shape part corresponding to the shape of the part is inserted. Next, the first die and the second die are brought into contact with each other to surround the periphery of the powder molded product. And
1st punch, 2nd punch, undercut support punch,
The powder molded article is compression molded by cooperation of the first die and the second die.

In this case, a support punch is provided at the undercut portion.
Sizing the powder molded product while inserting and supporting
Because of this, excessive force is applied to the powder molded product during sizing
No damage to the support punch
The thickness of the proximal end of the switch is smaller than the thickness of the distal end, and the width of the proximal end
Is smaller than the diameter of each die.
Insert the support punch into the slot
It can move in the axial direction and surround the powder molded product, and the tip
You can get inside the dice,
In addition, there is a gap between both dies and the support punch.
And deforms or breaks the support punch even when sizing
No misalignment between die and support punch
Wear.

[0009]

Next, an embodiment of the present invention will be described with reference to the drawings. In this embodiment, an example of sizing a double-row cam sprocket 1 having a shape as shown in FIG. 8 will be described. FIG. 1 is a side sectional view showing a main part of a sizing apparatus of the present embodiment, and FIG. 2 is a partial side sectional view showing a state where a sintered product is sized by the sizing apparatus. As shown in FIG. 1, the sizing apparatus has a lower punch (second punch) 13 supported by a lower base plate 11, and an upper part of the lower punch 13
An upper punch (first punch) 15 that is moved toward and away from the lower punch 13 by a driving unit (not shown) is attached. Therefore, by moving the upper and lower punches 13 and 15 relatively close to each other, the sintered product W placed on the lower punch 13 can be compressed from above and below as shown in FIG.

As shown in the figure, the sizing apparatus of this embodiment has a pair of support punches 17 which move forward and backward in a direction perpendicular to the direction of movement of the upper and lower punches 13 and 15. This support punch 17 is shown in FIGS.
As shown in (b), the undercut portion U of the sintered product W
It consists a tip portion 17a which is inserted (see FIG. 8), and continue Ku base end portion 17b on the distal end portion 17a. Base 1
The thickness of 7b is rather thin than the thickness of the tip portion 17a, the width is not smaller than the diameter of the die. Supporting lifting punch 17 is moved back and forth by a hydraulic cylinder 19, in a state of being matched the height of the supporting lifting punch 17 and the undercut portion U, is moved before proceeding position, supporting the punch as illustrated in FIG. 2 17 tip 1
7a is inserted into the undercut portion U of the sinter W. In this <br/> embodiment, the hydraulic cylinder 19 for driving the supporting punches 17 Toko support punch 17 also supports the lower punch 13
Of the base plate 11 , for example ,
As the base plate 11, that is, the lower punch 13 moves up and down
The lower punch 13 may be mounted so as to be movable up and down. The lower punch 13 is provided on the outer periphery of the lower punch 13 described above.
A lower die (second die) 21 which moves relatively up and down in a sliding state is attached to the lower die 21 .
A groove G corresponding to the base end 17b of the support punch 17 is provided in the contact surface S (see FIG. 6).

As shown in FIG. 4 or FIG. 5, a guide A is formed on the inner peripheral surface I of the lower die 21 on the contact surface S side. The guide A is used to prevent the sintered product W from coming into contact with the corners of the lower die 21 to prevent shaving or cracking of the sintered product, and to smoothly insert the sintered product W into the molded portion. Useful for. Guide A shown in FIG. 4, which tracks the radius at the corner portion is formed by chamfering the order of 0.3 mm to 1 mm, guide A shown in Figure 5, the contact of the molded inner peripheral surface I On the surface S side, an inner peripheral surface having a radius larger than the inner peripheral diameter by a distance E is formed.

On the other hand, on the outer periphery of the upper punch 15 is mounted an upper die (first die) 23 which moves up and down relative to the upper punch 15 in a sliding state.
Similarly to 1, a groove G corresponding to the support punch 17 is provided. Such two dies 21 and 23, are relatively close movement as shown in FIG. 2, the contact surface S, you molded <br/> abutted to sinter W and S.

Particularly, in the present embodiment, the width of the base end 17b of the support punch 17 is smaller than the upper and lower dies 21, 23, and the thickness of the base end 17b is determined by the two grooves G, G. since passage Q which is formed is smaller than the thickness (FIG. 6d), the distal end portion 17a of the support punch 17 in a state of being inserted into the undercut portion U of the sinter W, both dies 21,
23, the contact surfaces S, S can contact each other. Further, since a gap is formed between the passage Q and the support punch 17, even if the relative positions of the dies 21, 23 and the support punch 17 are shifted during sizing, a force is applied from one member to the other member. Is not added. Therefore, the support punch 17 is not deformed or damaged.

Similarly, when the undercut portion U is a part of the sintered product W, a gap can be formed between the dies 21 and 23 and the support punch.
7 is not deformed or damaged.

The dies 21, 23 are moved up and down by driving means (not shown) such as a hydraulic cylinder 19. As these driving means, various driving means such as a pneumatic cylinder and a motor mover can be used in addition to the hydraulic cylinder.

A procedure for sizing a sintered product W having an undercut portion U by using such a sizing device will be described with reference to FIG. In FIG. 6, in order to clarify the operation of each member, the operation will be described with reference to a diagram of a sizing apparatus whose structure is simplified.

As shown in FIG. 6A, first, the upper die 23 and the lower die 21 are separated from each other , and the compression surface 2 of the lower punch 13 is separated.
Height and abutting surface height S of the lower die 21 of 5 is consistent with form <br/> state, placing the sintered article W on the compression surface 25 of the lower punch 13. Next, as shown in FIG.
After the height of the undercut U of the support punch 17 matches the height of the tip 17a of the support punch 17, the tip 17a of the support punch 17 is inserted into the undercut U. Here, the thickness dimension T of the distal end portion 17a of the support punch 17 inserted into the undercut portion U is
In view of the pushing allowance at the time of sizing, the undercut portion U may be smaller than the dimension H in the height direction. By doing so, the tip portion 17 of the support punch 17
a can be smoothly inserted into the undercut portion U. Since the undercut portion U of the sintered product W is formed with high precision by an integral type, the tip portion 17 of the support punch 17 is always formed.
a can be inserted smoothly.

Subsequently, as shown in FIG. 6B, the upper punch 15 is moved downward in the figure, and the sintered product W is held in a state sandwiched from above and below in cooperation with the lower punch 13.
After the sintered product W is held by the upper and lower punches 13 and 15, the distal end portion 17a of the support punch 17 may be inserted into the undercut portion U of the sintered product W.

Further, as shown in FIG.
5 is moved down direction by a predetermined distance, inserting the lower sinter W inside the lower die 21. Note that the lower die 21 may be moved upward in the drawing, and the lower side of the sintered product W may be positioned inside the lower die 21. In this case , the support punch 17
The support punch 17 moves up and down with the lower punch 13.
Is located in a groove G formed on the contact surface S of the lower die 21. Thereafter, as shown in FIG.
Then, the upper die 23 is moved downward in the figure to
1 and the upper and lower dies 21, 22 around the sintered product W.
Hold by 3.

Here, the contact surface S of the upper die 23 is
Also , like the lower die 21, the base end 17 of the support punch 17
Since the grooves G corresponding to b is formed in a state of inserting the tip 17a of the support punch 17 to the undercut portion U of the sinter W, the contact surface S of the upper and lower dies 21, 23, S
They can abut each other. Moreover, the dies 21, 2
3 and between the supporting punch 17, since there is a gap as shown in FIG. 7, kill a shift of some relative positions allowable.

In this manner, the upper and lower punches 13, 15
Sinter W sandwiched state to the position <br/> up inside the die 21 and 23, it compresses the sinter W sandwiched by upper and lower punches 13 and 15, perform sizing. When Sai <br/> Jin grayed sintered article W is completed, after the upper die 23 and lower die 21 respectively is moved away from the other die, supporting the punch 17
From the undercut U and the upper punch 15
Is moved upward in the figure, and the product after sizing on the lower punch 13 is taken out.

When the undercut portion U exists over the entire circumference of the sintered product W, the contact surfaces S, S of the dies 21 and 23 do not contact the sintered product W. no burr is generated in the contact portion of the contact surface S, S and sinter W. If the undercut portion U there Ru on a part of the outer circumference of the sintered article W is the contact position between the contact surface S and the sintered product W of the die 21 and 23, there is a so-called burr occurs.
However, in the sizing apparatus of the present embodiment, since the position where the burr is generated is on the outer periphery of the sintered products W, thereby removing easily burr compared to other locations.

In the sizing of the double chain type sprocket 1 shown in FIGS. 8A and 8B, the flank M is formed at the tooth tip 31 as shown in FIG. The tip 17a of the punch 17 does not come into contact with the tip 17a. The flank M can be dimensionally corrected without being supported by a die or a punch, so that there is no problem. When the flank M is not formed, the support punch 17 may be formed as shown in FIG. 10 so that the tooth tip 31 and the support punch 17 do not come into contact with each other.

[0024]

In inserting the support punch undercut flour powder workpiece carrier state according to the present invention, since the sizing of the powder molded product, without excessive force is applied to the powder molded product during sizing, damage And other problems can be prevented. Ma
In the configuration of the support punch, the thickness of the base end is
Thickness and base width is less than the diameter of each die
Insert a support punch into the undercut to support
The die is moved in the axial direction even when the
The surrounding area can be surrounded, and the tip can penetrate into the die
As a result, the powder molding can be pushed deep into the die.
Can be included. In addition, between the dies and the support punch
The gap is formed at the tip of the undercut.
Change the support punch even when sizing with the
The die and the support
Slight deviation of the relative position due to the gap between
Wear.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a sizing device of the present embodiment.

FIG. 2 is a partial side sectional view showing a sizing device of the present embodiment.

FIG. 3 is a plan view and a side sectional view showing a support punch.

FIG. 4 is a partially enlarged view showing a die guide.

FIG. 5 is a partially enlarged view showing another embodiment of a die guide.

FIG. 6 is a side sectional view for explaining the operation of the sizing device of the present embodiment.

FIG. 7 is a side sectional view showing a state in which a support punch is inserted into an undercut portion.

FIG. 8 is a plan view and a side sectional view showing a double chain type sprocket.

FIG. 9 is a side sectional view showing a support punch of another embodiment.

FIG. 10 is a side sectional view showing still another embodiment of the support punch.

FIG. 11 is a side sectional view showing a conventional sizing device.

FIG. 12 is a side sectional view showing a conventional sizing device.

[Explanation of symbols]

Reference numeral 13: lower punch, 15: upper punch, 17: support punch, 17a: distal end, 17b: base end, 21: lower die, 23: upper die, S: contact surface, U: undercut portion, Q: Groove, W: Powder molded product.

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B22F 3/24

Claims (1)

(57) [Claims] 1. A first punch and a second punch which hold both ends in the axial direction of a powder molded product having an undercut portion formed on a side face and compress by moving relatively close in the axial direction. A first die and a second die provided coaxially with the punch and configured to surround the powder molded product over its entire circumference and to move relatively close to and away from each other;
A support punch configured to be insertable / removable with respect to an undercut portion of the powder molded product and to be able to move up and down together with the powder molded product in an inserted state; The punch has a distal end inserted into the undercut portion of the powder molded product, and a base end following the distal end,
The thickness of the proximal end is smaller than the thickness of the distal end, and the width of the proximal end is configured to be smaller than the diameter of each of the dies. The state in which the distal end of the support punch is inserted into an undercut portion Then, when the first die and the second die are moved close to each other, the base end of the support punch is located in a groove provided on the contact surface of each of the dies, and is located between the base end and each of the dies. A sizing apparatus for a powder molded product, wherein a predetermined gap is formed.