JPH07185896A - Compression molding method of powder molded goods and device therefor - Google Patents

Abstract

PURPOSE:To form parts having intricate shapes by one time of compression molding without increasing the size of a device by applying compressive force to plural punches by using one piece of sliding block. CONSTITUTION:A pair of the upper and lower punches 15, 17 which fit into through-holes 13 of a die 11 and mold powder materials are disposed freely attachably and detachably. The lower punch 7 is composed of concentrically arranged and freely slidable punches 19, 21, 23, 25. The sliding block 29 freely movable to a compression position where the compressive force is imparted to at least >=2 among these molding punches and a release position where the compressive force is not imparted thereto is mounted at a base plate S of the molding device. The molding punches 21, 23, 25 are supported by supporting means which position the punches to the positions at the time of packing the powders. A sliding member for assuring the route to move the sliding block 29 to the release position and moving the molding punches 21, 23, 25 to the retreat positions at the time of drawing out the molded parts after the compression molding is disposed in the die 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compression molding apparatus for sintering machine parts made of powder material, and more particularly to a compression molding method and apparatus for compressing a plurality of punches by one sliding block.

[0002]

2. Description of the Related Art Since a so-called sintered machine part is manufactured by sintering a molded product molded into a desired shape, it is possible to greatly reduce machining processes such as cutting in the manufacturing process. Due to such characteristics, the sintering machine parts have been used in various parts in recent years, including a sprocket of a chain and a pulley mounted on a rotary shaft.

FIG. 5 is a sectional view showing an example of the shape of a sprocket S which is a sintering machine component. As shown in the figure, this sprocket S has an end surface S1 of the boss portion and a side surface S2 of the outer peripheral portion having teeth on the peripheral portion on one side surface, and a plurality of steps are formed.

FIG. 6 (A) is a partial sectional view showing an example of a compression molding apparatus for molding the sprocket S having the above-described stepped shape. As shown in the figure, this compression molding apparatus has a die 11 that defines the periphery of the space filled with the powder material, and this die 11 is vertically movable with respect to a base B of the compression molding apparatus. is set up. Further, the compression molding apparatus has an upper punch (not shown) that is vertically movable. Below the upper punch, a lower punch 17 is installed which moves up and down relative to the upper punch so as to be able to move closer to and away from the upper punch. The lower punch 17 forms a stepped surface.

As shown in FIG. 6 (A), the lower punch 17 has a core 19 forming a central hole H of the sprocket S.
And a first lower punch 21 for compression-molding the end surface of the boss portion,
It is composed of a second lower punch 23 forming an outer peripheral portion, and the core 19 and the punches 21 and 23 are concentrically arranged and slidably contactable. And these members are
Each can move independently. In this way, if the punches 21 and 23 can be independently moved up and down,
The density of the powder material of the entire sprocket S to be compression molded can be made uniform.

The lower punch 17 thus divided into a plurality of pieces
Of the second lower punch 23 for forming the side surface S2 of the outer peripheral portion
The sliding block 29 formed below the lower punch 17 applies a compressive force to the sheet.

The sliding block 29 is installed on the base B so as to be horizontally movable, and is movable back and forth between a forward movement limit position shown in FIG. 6 (A) and a backward movement limit position shown in FIG. 6 (C). Has become. Then, at the forward limit position, the base end portion 2 of the second lower punch 23 moved downward
The second lower punch 23 is brought into contact with the third lower punch 23 and a compressive force is applied to the second lower punch 23. When the second lower punch 23 is moved to the retracted limit position, the second lower punch 23 does not come into contact with the base end portion 23a.

The sliding block 29 is moved to the retreat limit position by a slide protrusion 31 which is vertically movable on the die 11. That is, this slide protrusion 31 has an inclined rack 33, and when the slide protrusion 31 is moved downward, the rack 33 engages with the pinion gear 35 of the sliding block 29,
The sliding block 29 is moved backward.

Therefore, when the powder molded product is molded by the upper and lower punches, the sliding block 29 is positioned at the forward limit position so that a compressive force can be applied to the second lower punch 23. When the compression molded powder molded product is taken out, the sliding block 29 is moved downward in conjunction with the downward movement of the die 11 to move the sliding block 29 to the retreat limit position, and the second lower punch 23. Is secured to a lowermost position, and by moving the die 11 and the second lower punch 23 below, the molded product is relatively moved upward by the core 19 and the first lower punch 21 so that it can be extracted. .

[0010]

However, the sliding block 29 prevents the compression force at the time of compression molding from being increased to the second value.
In the structure provided to the lower punch 23, the shape of the sintered mechanical component to be molded becomes more complicated, and when the number of divisions of the lower punch 17 is increased, the sliding block 29 must be increased, The structure of the compression molding apparatus, particularly the die set section, becomes extremely complicated. Also, in the current die set section, it is difficult to add more sliding blocks due to space limitations.

Therefore, for example, when forming a sprocket S having a relatively complicated final shape as shown in FIG. 3, it is not possible to form all the steps during compression molding,
In FIG. 4, an extra portion D indicated by diagonal lines remains. When such a portion D remains, a machining process such as cutting is required in addition to the compression molding process and the sintering process. That is, the number of steps is increased. Further, during machining, unfavorable mechanical properties may appear or defects may occur due to work hardening or the like, and durability may be deteriorated.

The present invention, which has been made in view of the above problems, divides the lower punch without increasing the size of the apparatus by applying a compressive force to the plurality of punches by one sliding block. It is an object of the present invention to provide a compression molding apparatus capable of increasing the number of parts and forming a more complicated shape by only compression molding.

[0013]

A compression molding apparatus for a powder molded article according to the present invention which achieves the above object is provided with a die having a through hole filled with a powder material so as to be movable toward and away from a base. A pair of punches that fit into the through holes of the die and form a mold space filled with the powder material are installed so as to be relatively close to and away from each other, and one of the pair of punches is concentrically arranged. A compression molding apparatus for a powder molded product configured by a plurality of molding punches, wherein a compression position for applying a compression force to at least two molding punches of the plurality of molding punches and a compression force are applied to the base. A movable sliding block is attached to a release position where the powder is not applied, and the at least two or more forming punches are respectively supported by supporting means for positioning at the powder filling position, The die is provided with a slide member for moving the sliding block to the release position and ensuring a path capable of moving the at least two or more molding punches to the retreat limit position when the molded product is taken out. Is characterized by.

In another compression molding apparatus for powder molded products, the bases of the two or more molding punches are arranged in a state of being stacked so as to come into contact with and separate from the sliding block in the axial direction.

In still another compression molding apparatus for powder molded products, the two or more molding punches are arranged such that the bases of the molding punches on the outer peripheral side are stacked so as to be able to come into contact with and separate from the bases of the molding punches on the inner peripheral side. It is arranged.

Further, in the compression molding method for a powder molded article according to the present invention which achieves the above object, a die having a through hole filled with a powder material, and the powder material is filled by fitting into the through hole of the die. A powder material filling step of filling a powder material into a mold space formed by a pair of punches forming a mold space, the die, and the pair of molding punches arranged concentrically. Of one of the punches, and a compression molding step of compression molding the powder material filled in the mold space with the other punch, the method comprising: In the powder material filling step, at least two or more forming punches of the plurality of forming punches, which are positioned at predetermined positions by separate supporting members, are formed into one slide. Is pressed in bridging block is characterized in that the compression molding step of compressing the powder material.

[0017]

In the compression molding apparatus for powder molded products having such characteristics, the powder material is first filled in the mold space. At this time, at least two or more forming punches of the plurality of forming punches are supported at predetermined positions by separate supporting means. When the powder material is filled, both punches are moved relatively close to each other and the punch material is fitted into the through hole of the die to compress the powder material to form a predetermined shape. At this time, the sliding block moved to the compression position applies a compressive force to at least two or more molding punches that were individually supported at the time of filling the powder material. After the compression molding is completed in this way, when the die is moved backward, the slide protrusion is moved forward to move the sliding block to the release position. In this case, at least two or more forming punches can be moved to the retract limit position, so that these forming punches are moved to the retract limit position. Then, the molded powder molded product is extracted from the die.

Further, according to the compression molding method of the powder molded product, at least two or more molding punches of the plurality of molding punches which are individually supported in the powder material filling step are pressed by the one sliding block to form the powder material. Compression molded.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a compression molding apparatus of this embodiment will be described with reference to the drawings. The same members as those already described are designated by the same reference numerals, and the description thereof may be omitted. FIG. 1 is a cross-sectional view showing a main part of a compression molding device when a powder material is filled. FIG. 2 is a partial cross-sectional view showing a state in each step of the second lower punch and the third lower punch.

As shown, the compression molding apparatus is
Through hole 13 that defines the periphery of the space filled with the powder material
The die 11 having the
Is installed so as to be movable up and down with respect to the base B of the compression molding apparatus. Further, the through hole 13 of the die 11 is formed in the shape of the peripheral portion of the compression molded product to be formed. For example, in the compression molding apparatus for molding the sprocket S having the shape shown in FIG. , Tooth-shaped.

Further, as shown in FIG. 1, an upper punch (first punch) 15 which is vertically movable is installed above the die 11. When the upper punch 15 is moved downward, the upper punch 15 fits into the through hole 13 of the die 11. Upper punch 15
A lower punch (second punch) 17 that moves up and down relative to the upper punch 15 so as to be movable toward and away from the upper punch 15 is installed below the. As shown in FIG. 1, this lower punch 17 is
Core 19 forming the inner peripheral surface of the central hole H of the sprocket S
And the first lower punch 21 for compression-molding the end surface of the boss B.
And a second lower punch 23 forming an outer peripheral portion and a third lower punch 25 forming a step at the outermost peripheral portion,
The core 19 and the punches (forming punches) 21, 23, 25 are installed concentrically and slidably. And these members can move up and down independently. That is, the innermost core 19 is moved up and down by the rod 27 of the first drive cylinder to be connected. The first lower punch 21 is supported on the base B, and moves up and down relatively by the vertical movement of the core 19 and the other lower punches 23 and 25.

On the other hand, the second and third lower punches 23, 25
Is supported by a supporting means (not shown) such as a hydraulic cylinder.
Each is supported separately. Both supporting means (not shown) are means for positioning the lower punches 23, 25 at the position when the powder material is filled, that is, at the filling position, and do not apply a compression force at the time of compression molding. Therefore,
It is sufficient that each lower punch can be moved up and down, and it can be installed in a relatively small space. The base B applies a compressive force to the first lower punch 21.

The second and third lower punches 23, 25
In the sliding block 29 installed on the base B
The compression force is applied during compression molding. As shown in FIG. 1, the sliding block 29 is installed on the base B so as to be movable back and forth in the horizontal direction, and is biased toward the center of the mold, that is, the right side in the figure by a biasing means (not shown). Therefore, it is normally moved to the forward travel limit position (compression position) shown in FIGS. 2 (A) and 2 (B). When the second lower punch 23 is moved downward when the sliding block 29 is located at the forward movement limit position, the base end portion 23a of the second lower punch 23 abuts on the sliding block 29, and the sliding block 29 moves to the first position. Two
Compressive force is applied to the lower punch 23. When the third lower punch 25 moves relatively downward with respect to the second lower punch 23, the adapter 25a supporting the third lower punch abuts on the base end portion 23a of the second lower punch 23, so that the sliding block 29 Is applied to the third lower punch 25 via the second lower punch 23.

That is, in the lower punches 23 and 25, the supporting means for positioning the lower punches 23 and 25 at the positions when the powder material is filled as shown in FIG. The means (sliding block) for applying the compressive force is shared. In this way, when the sliding block (compressing means) 29 is shared, the lower punch 17 is divided only by adding a relatively small supporting means (not shown), that is, without adding the sliding block 29. The number can be increased.
Therefore, even when it is difficult to add the sliding blocks 29 due to the restriction of the installation space as in the present embodiment, the number of divisions of the lower punch 17 can be increased.

Even if the sliding block 29 is shared as in the present embodiment, if the supporting means for positioning the lower punches 23, 25 at the position when the powder material is filled are provided separately, the punches 21, The stroke distance at the time of compression can be changed every 23 and 25. That is, the stroke distance at the time of compression molding is set to the lower punches 21, 23, 25
Can be set independently for each. Therefore, each lower punch 2
The stroke distance of 1, 23, 25 can be made proportional to the thickness of the corresponding portion, and if the powder material is filled in an appropriate amount in advance, the density of the powder material of the sprocket S to be compression molded becomes uniform. be able to.

As shown in FIG. 1, the sliding block 29 has a through-passage 2 extending vertically.
9a is formed, and the dice 11 is formed in the through path 29a.
A pinion gear 35 that can be meshed with a rack 33 of a slide protrusion 31 that is vertically movably attached is attached. Since the meshing surface 33a of the rack 33 is inclined with respect to the vertical direction, when the sliding projection 31 is moved downward and the meshing surface 33a of the rack 33 meshes with the pinion gear 35 of the sliding block 29, the sliding block 29 is removed. , A retreat limit position (release position) shown in FIG. 2C against the biasing force of a biasing member (not shown).
Be moved to. In this state, the second lower punch 17 does not come into contact with the sliding block 29 even if it is moved downward, and thus can move to the lower limit position.

A procedure for compression-molding a powder material to form a compression-molded product having a desired shape by the compression-molding apparatus having such a structure will be described with reference to FIG. Note that FIG.
(A) is a partial cross-sectional view showing a state of the second lower punch and the third lower punch at the time of filling the powder material, FIG. 2 (B),
FIG. 2C is a partial sectional view showing a state at the time of compression molding, and FIG. 2C is a partial sectional view showing a state at the time of extraction. The shape of the sprocket molded by the compression molding device of this embodiment is the shape shown in FIG. Hereinafter, the powder material filling step will be described as a starting point.

As shown in FIG. 2A and FIG.
The upper punch 15 has been moved upward and separated from the lower punch 17. On the other hand, the core 19 and the first to third lower punches 21, 23, 25 constituting the lower punch 17 are
Each of the sprockets S is positioned at a predetermined position corresponding to the shape of the sprocket S to be formed. Of these, the core 19 forming the inner diameter of the central hole H of the sprocket S is positioned at a position where the tip end surface thereof coincides with the upper surface of the die 11. The second lower punch 23 and the third lower punch 25 are respectively positioned at predetermined positions by a supporting member (not shown). The first lower punch 21 is supported on the base B, and the core 19, the second and third lower punches 23,
By positioning 25 at a predetermined position, it is relatively positioned.

The positioning positions of the punches 21, 23, 25 are determined in proportion to the thickness of the sprocket S at the portions where the punches 21, 23, 25 come into contact with each other. When the positions of the lower punches 21, 23, 25 are positioned in this way, the upper surface of the powder material supplied into the mold space is made to coincide with the upper surface of the die 11, whereby the supply amount and the thickness of each part of the sprocket S are increased. And can be easily proportional. Therefore, the stroke distance of each punch 21, 23, 25 at the time of compression molding is determined by the compression molded sprocket S.
When the sprocket S is compression molded into a desired shape, the density of the entire powder material can be made uniform by making it proportional to the thickness.

When the positioning of the upper and lower punches 15 and 17 is completed and the powder material is filled in the mold space of the lower punch 17,
Next, the upper punch 15 is moved downward, and the powder material is compression-molded. At this time, the slide protrusion 31 attached to the die 11 is moved relatively upward with respect to the die 11, and the sliding block 29 is moved to the advance limit position as shown in FIG. 2B. Therefore, when the upper punch 15 is moved downward, the base end portion 23 a of the second lower punch 23 comes into contact with the sliding block 29, and the compressive force is applied to the second lower punch 23. When the compressive force is applied to the second lower punch, the compressive force is also applied to the third lower punch 25 that contacts the second lower punch at the adapter 25a. That is, the compression force is applied to the second lower punch 23 and the third lower punch 25 from the same sliding block 29.

When the compression molding of the powder material is completed in this way, as shown in FIG. 2C, the core 19 and the die 11 are relatively moved downward, and the molded sprocket S (not shown). ) Can be pulled out upward from the die 11. When the extracted sprocket S is carried out by a conveying means (not shown), the core 19 of the lower punch 17 and the lower punches 21, 23, 25 are moved to the position shown in FIG.
The powder material is moved to the position shown in (A) at the time of powder material filling, and the powder material for the sprocket to be compression-molded next is filled in the mold space.

As described above, in the compression molding apparatus of the present embodiment, the sliding block 29 is shared by the second lower punch 23 and the third lower punch 25, so that the compression molding apparatus is maintained in a compact state. It is possible to increase the number of punch divisions. In this way, if the number of divisions of the punch can be increased, it is possible to mold a part having a more complicated shape only by compression molding, that is, without using machining such as cutting. Further, since the component can be molded into a desired shape only by compression molding, the weight of the component can be reduced without using machining.

In the above embodiment, the support means for positioning the third lower punch independently of the second lower punch at the time of filling the powder material is provided, but the third lower punch is provided with a spring or the like. The supporting means for the third lower punch can be omitted by supporting the supporting means for the second lower punch.

[0034]

As described above, according to the present invention, the compression force is applied to the plurality of punches by one sliding block, so that the lower punch is divided without increasing the size of the compression molding apparatus. The number can be increased. Therefore, a more complicated shaped part can be formed only by compression molding, and machining is unnecessary.

Further, since the component can be molded into a desired shape only by compression molding, it is possible to reduce the weight of the component without using machining.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a main part of a compression molding device when a powder material is filled.

FIG. 2 is a partial cross-sectional view showing a state in each step of the second and third lower punches.

FIG. 3 is a sectional view showing a sprocket formed by the compression molding apparatus of the embodiment.

FIG. 4 is a cross-sectional view showing a difference in shape between a sprocket formed by the compression molding apparatus of the embodiment and a sprocket formed by the compression molding apparatus described in the related art.

FIG. 5 is a cross-sectional view showing the shape of a sprocket formed by the compression molding apparatus described in the related art.

FIG. 6 is a partial cross-sectional view showing a conventional compression molding device.

[Explanation of symbols]

11 ... Dice, 15 ... Upper punch, 1
7 ... Lower punch, 19 ... Core, 21 ... 1st lower punch, 23 ... 2nd lower punch, 25 ... 3rd lower punch, 29 ... Sliding block, 31 ... Sliding protrusion, 33 ... Rack, 35 ... Pinion gear.

Claims (4)

[Claims] 1. A die having a through hole filled with a powder material is provided so as to be movable toward and away from a base, and fitted into the through hole of the die to form a mold space filled with the powder material. A pair of punches are installed so that they can move closer to and away from each other,
What is claimed is: 1. A compression molding device for a powder molded product, comprising one of the pair of punches, the plurality of molding punches arranged concentrically, wherein the base has at least two of the plurality of molding punches. A compression position for applying a compression force to the above forming punch,
A movable sliding block is attached to a release position where no compression force is applied, and at least two or more molding punches are respectively supported by supporting means for positioning at a powder filling position to obtain a compression molded product. Powder molding, wherein the die is provided with a slide member that moves the sliding block to the release position and secures a path through which the at least two or more molding punches can be moved to the retreat limit position during extraction. Compression molding equipment. 2. The compression molding apparatus for a powder molded product according to claim 1, wherein the bases of the two or more molding punches are arranged in a state of being stacked so as to come into contact with and separate from the sliding block in the axial direction. 3. The powder according to claim 2, wherein the two or more forming punches are arranged such that the bases of the forming punches on the outer peripheral side are arranged in a state of stacking on the bases of the forming punches on the inner peripheral side so as to come into contact with and separate from each other. Compression molding equipment for molded products. 4. A die space formed by a die having a through hole filled with a powder material and a pair of punches fitted in the through hole of the die to form a die space filled with the powder material. A powder material filling step of filling a powder material therein, the die, one punch of the pair of punches configured by a plurality of forming punches arranged concentrically, and the other punch, A compression molding method for a powder molded article, comprising: a compression molding step of compressing and molding a powder material filled in a mold space, wherein the compression molding step is performed by separate supporting members in the powder material filling step. Molding step of compressing the powder material by pressing at least two or more molding punches of the plurality of molding punches positioned at the position of 1 with a single sliding block. Compression molding method of the powder molded product, characterized in that the.