JP2011080113A - Die for sizing sintered component and sizing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To smoothly perform an operation of continuously correcting the size of a sintered component which is an object to be sized on a turn table included in a sizing apparatus while transporting the sintered component to a workpiece-charging part, a press part and a workpiece-discharging part in this order. <P>SOLUTION: This sizing apparatus includes a lower punch holder 9; a lower punch 3 of a sizing die installed thereon; a lower punch pressure foot 13 which has such a gap g provided between the lower punch 3 and itself as to permit a relative movement of the lower punch 3 in an axial direction; and further an elastic member 10 which pressurizes the lower punch 3 upward. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  This invention employs a sizing die that sizing a sintered part and forcibly detaching the part after completion of sizing from the lower punch so that the part can be reliably extracted, and the die. Relates to the sizing apparatus.

  In the production of sintered parts, a green compacting process in which raw material powder is molded with a press machine and a sintering process in which a compact obtained by compacting is sintered. In addition, when high dimensional accuracy is required for a product, sizing processing for dimensional correction is performed using a press. The sizing die used at this time is a combination of a die and upper and lower punches, and a core or the like as necessary.

  In order to increase production efficiency, the sizing process in the mold may be performed in a continuous operation using equipment equipped with a turntable for carrying in and out sintered parts. The turntable includes a workpiece insertion hole disposed above the die, and an indenter protruding inside the hole, and allows sintered parts before and after sizing to enter the workpiece insertion hole, and from the side with the indenter. Press down and hold. The work insertion holes are holes that penetrate vertically, and are provided at a constant pitch on a circle concentric with the rotation center of the turntable.

  In the turntable, the workpiece insertion hole moves in the order of the workpiece loading part, pressing part, and workpiece discharging part by rotating the table, and the sintered parts received at the workpiece loading part are placed in the pressing part (above the sizing die). Be transported. Further, the sintered part is taken into the workpiece insertion hole again after sizing, and is conveyed to the workpiece discharge section by rotating the table.

  A sizing method using this turntable is disclosed in, for example, Patent Document 1 below. In Patent Document 1, sizing in continuous work by rotating a table can be efficiently performed by using the above-described turntable (rotary table).

JP 2007-2111269 A

  In sizing using the above turntable, in the die cutting process after sizing, the sintered parts extracted from the sizing die are introduced into the workpiece insertion hole waiting above the die and held with an indenter, After that, the lower punch of the sizing mold is pulled down to disengage the sintered part from the lower punch. However, depending on the shape of the molding surface (upper surface) of the lower punch, the sintered part that has been sized is in close contact with the lower punch. It may not be easily removed from the lower punch, and it may not be possible to carry it out by the turntable, preventing continuous work.

  Also in the sizing apparatus using the technique of Patent Document 1, if the adhesion between the lower punch and the sintered part is larger than the part holding force by the indenter, the sintered part is not held by the indenter, and the product remains in the press part. This makes it impossible to size subsequent parts.

  An object of the present invention is to solve the above-described problems so that a continuous sizing operation using a turntable is smoothly performed.

In order to solve the above-described problems, in the present invention, a sizing die for correcting a size by pressing a sintered part with an upper punch to be pressed into a die forming hole is configured as follows.
That is, a lower punch holder, a lower punch installed on the lower punch holder and opposed to the upper punch, and fitted to a side surface of the lower punch, and the lower punch is disposed between the lower punch in the axial direction. It has a lower punch presser with a gap that allows relative movement in the axial direction,
Further, an elastic member for urging the lower punch upward is provided.

  The elastic member is preferably a spring. The elastic member can be disposed between the lower punch and the lower punch holder, but is preferably disposed between the lower punch and the lower punch holder.

  In addition, the present invention is preferably applied to a sizing die having a molding surface in which the lower punch is convex or concave upward.

The present invention has the above-described sizing mold of the present invention, and a turntable for carrying in and out of the sizing target sintered part into the press part,
An indenter capable of appearing and retracting in the pressing direction for pressing and holding a workpiece insertion hole disposed above the die of the sizing mold on the turntable and a sizing sintered part inserted into the hole from the side. Also provided is a sizing device for sintered parts.

  The indenter may be a known ball plunger or the like, and this indenter is provided along the edge of the workpiece insertion hole.

  In the conventional sizing device, when the adhesion between the lower punch and the sintered part is large, the sintered part is not separated from the lower punch. Even in sizing using a turntable provided with an indenter, if the adhesion force is larger than the holding force of the sized product by the indenter, the sintered part is not separated from the lower punch, and the work by the turntable cannot be performed.

  In contrast, in the sizing device of the present invention, the elastic member installed in the lower punch is compressed in the sizing process, and the frictional force between the sintered part and the die is reduced in the process of extracting the sintered part from the die. Sometimes the elastic member is elastically restored. The lower punch pushed up by the elastic member hits the lower punch presser and stops rising. Due to the impact force at that time, the sintered part that is in close contact with the lower punch is separated from the lower punch. The sintered part detached from the lower punch is thrown upward by the inertial force, and can be held on the turntable by receiving and supporting it by the protruding indenter. Thereby, the sizing using a turntable can be performed smoothly.

  Conveyance of the sintered parts for sizing from the work input part to the press part is performed by inserting the sintered parts into the work insertion holes of the turntable in the work input part and holding the sintered parts by pressing the indenter from the side. In this state, it is performed by rotating the turntable.

  The elastic member can be easily manufactured by using a spring, and the repulsive force can be controlled. Further, by disposing the elastic member between the lower punch and the lower punch holder, the elastic member can be incorporated into the lower punch holder to simplify and miniaturize the mold.

  The sizing mold with the lower punch having a molding surface that is convex or concave upwards is compressed and corrected by compressing the sintered part during sizing. The adhesion is greater than a mold with a flat bottom punch. The present invention is particularly effective when applied to a mold in which such a lower punch is used.

Sectional drawing which shows an example of the sizing metal mold | die and sizing apparatus of this invention Sectional drawing which shows the die extraction state of the sizing apparatus of FIG. The figure which expanded the principal part of FIG. The top view which shows a part of turntable provided in the sizing apparatus of FIG. Sectional drawing along XX of FIG. 4 of the work holding unit provided in the turntable Sectional drawing along YY of FIG. 4 of the work holding unit provided in the turntable The figure which shows the example which installed the elastic member which urges | biases a lower punch between a lower punch and a lower punch press Perspective view showing an example of sintered parts to be sized

  Embodiments of the sizing apparatus according to the present invention will be described below with reference to FIGS. The sizing apparatus shown in FIGS. 1 to 3 corrects the dimension W of the sintered part A shown in FIG. 8 and includes a sizing mold 1 and a turntable 20.

  The illustrated sintered part A is a known bearing cap that is fixed to the engine block and holds the bearing of the crankshaft, and the lower surface that is corrected by the lower punch 3 of the sizing mold 1 is a semicircular concave surface. ing.

  The sizing die 1 employed in the illustrated sizing apparatus includes a die 2, a lower punch 3 inserted into a molding hole 2a of the die 2, two core rods 4 penetrating the lower punch 3, and a lower punch 3 And an upper punch 5 facing each other.

  The die 2 is supported by a die plate 6, and the die plate 6 is connected to a fixed plate 8 by a connecting rod 7. The lower punch 3 is installed on the lower punch holder 9, and an elastic member 10 that biases the lower punch 3 upward is disposed between the lower punch holder 9 and the lower punch 3.

The elastic member 10 is preferably composed of a spring such as a coil spring or a disc spring for the reasons already described.
Reference numeral 14 in FIG. 1 denotes an actuator for raising and lowering the core rod 4 (in the figure, a cylinder that operates by fluid pressure).

  The lower punch holder 9 is supported by the movable plate 12. The movable plate 12 is driven by a lifting / lowering actuator (not shown) connected via a connecting rod 11 and moved up and down together with the lower punch holder 9 to move the lower punch 3 from the sizing completion position in FIG. The sinter-sintered sintered part A is extracted from the die forming hole 2a.

  The lower punch 3 is attached to the lower punch holder 9 by using a lower punch press 13 that is fitted to the side surface of the lower punch 3. The lower punch presser 13 is fastened to the lower punch holder 9 with a bolt. Between the lower punch presser 13 and the lower punch 3, there is provided a gap g that allows the relative movement of both of them in the axial direction.

  As shown in FIGS. 4 to 6, the turntable 20 includes a disk table body 21, a plurality of work holding units 22 assembled to the table body 21, and a drive mechanism (not shown) that rotates the table body 21 intermittently. Z)).

  The table body 21 of the turntable 20 is provided with assembly holes 21a penetrating in the thickness direction of the body at a constant pitch on a circle concentric with the center of rotation, and the work holding units 22 are respectively keyed into the assembly holes 21a. It is assembled with anti-rotation by such as.

  The workpiece holding unit 22 moves in the order of the workpiece loading unit, the pressing unit, and the workpiece discharging unit by rotating the table, receives the sintered parts at the workpiece loading unit, transports them to the pressing unit, and supplies them to the sizing mold at the pressing unit. To do. Then, the sintered parts after sizing are received again and conveyed to the workpiece discharge unit by subsequent table rotation. Moreover, after conveyance, it returns to a workpiece | work insertion part and repeats said operation | movement.

  The workpiece holding unit 22 has a workpiece insertion hole 23 penetrating vertically in the center. In addition, an indenter 24 that protrudes inside the workpiece insertion hole 23 is provided. The illustrated indenter 24 is a known ball plunger that presses the ball 24a against the sintered part A to be held by the force of the spring 24b.

  A plurality of indenters (ball plungers) 24 are provided opposite to both sides of the workpiece insertion hole 23 (position along the lower edge of the semicircle on the side surface of the sintered part A). It can be projected and retracted from a hole surface at a position opposite to the workpiece insertion hole 23. The illustrated indenter 24 can change the pressing pressure (holding force) of the ball 24a against the sintered part A by changing the screwing amount of the adjusting screw 24c that receives one end of the spring 24b.

  Although the work holding unit 22 facilitates the assembly of the indenter 24, the work holding unit 22 is not an essential element because the work insertion hole 23 can be directly formed in the table body 21.

  In the illustrated sizing apparatus, the sintered part A to be sized is set in the workpiece insertion hole 23 of the turntable 20 in the workpiece input unit. The sintered part is held by the turntable 20 at this time by a method in which the ball 24 a of the indenter 24 is pressed from the side against the sintered part A inserted into the workpiece insertion hole 23.

  The sintered part A is conveyed to the press unit by the rotation of the turntable 20 and is disposed above the die 2. Thereafter, the upper ram 15 of the press machine is driven, and the upper punch 5 connected to the upper ram 15 is lowered, and the sintered part A in the workpiece insertion hole 23 is pushed down and transferred to the forming hole 2a of the die 2. Subsequently, sizing is performed by pressing the sintered part A with the upper punch 5 and pushing it into the molding hole 2a, and the operation is completed at the position where the upper punch 5 is lowered to the bottom dead center.

  Thereafter, the core rod 4 is lowered and pulled out from the sintered part A, and further, the lower punch 3 is raised and the sintered part A is extracted from the molding hole 2a. The sintered part A extracted from the forming hole 2 a is returned to the workpiece insertion hole 23 waiting above the die 2. The sizing device of the present invention is characterized by the operation at this time.

  The lower punch 3 of the sizing die 1 shown in the figure is configured as a convex arc surface corresponding to the semicircular concave surface of the sintered part (bearing cap) A at the tip molding surface 3a. Then, the sintered part A is unevenly fitted to the lower punch 3, and a situation occurs in which the sintered part A is hugged by the lower punch 3 by compression correction at the time of sizing, and a large adhesion force may be generated between the two. .

  In the sizing apparatus of the present invention, the holding of the sintered part A after sizing by the turntable 20 surely overcomes the adhesion force.

  The lower punch 3 is moved to a position where the gap g with the lower punch presser 13 becomes 0 because the elastic member 10 is pressed and compressed by the upper punch 5 during sizing. When the lower punch holder 9 is lifted and the sintered part A comes out of the die forming hole 2a, the elastic force of the elastic member becomes larger than the frictional force between the sintered part A and the die forming hole 2a. The member 10 is elastically restored. Therefore, the lower punch 3 is pushed up in the axial direction to the position where the gap g is generated under the force of the elastic member 10. The lower punch 3 thus pushed up collides with the lower punch presser 13 and its movement is restricted. The sintered part A is separated from the lower punch 3 by the impact at that time.

The sintered part A separated from the lower punch 3 passes through the workpiece insertion hole 23 and then falls. Then, it rests on the indenter (ball 24a) protruding in the workpiece insertion hole 23 during that time. Thus, the detachment of the sintered part A from the lower punch 3 is stably performed, and the lower punch 3 returns to the initial position without dragging the sintered part A. For this reason, the continuous operation of sizing is not interrupted.
Further, by adjusting the holding force by the indenter, the sintered part A separated from the lower punch 3 can be held on the turntable without passing through.

  The sintered sintered part A returned to the turntable 20 is moved to the work discharge portion by the rotation of the turntable 20, and is pushed up from below at that position to be pulled out from the work insertion hole 23 and taken out to the outside.

  As shown in FIG. 1, when the elastic member 10 is disposed between the lower punch 3 and the lower punch holder 9, a concave portion 9a corresponding to the core rod 4 is formed on the upper surface of the lower punch holder 9, and the concave portion 9a The elastic member 10 can be accommodated, and the sizing device can be easily simplified and downsized. In addition, the position of the elastic member 10 can be preferably maintained by using the core rod 4. However, as shown in FIG. 7, the elastic member 10 may be disposed between the lower punch 3 and the lower punch presser 13. it can. In FIG. 7, a spring receiver 16 is provided on the outer periphery of the lower punch 3, and the elastic member 10 is disposed between the spring receiver 16 and the lower punch retainer 13, and the object of the invention is achieved even with this structure.

  The exemplified sintered part A can also be corrected with the concave molding surface of the lower punch with the upper surface formed on the convex surface down. Also in this case, since the lower punch and the sintered part are concavo-convexly fitted and the adhesive force between the two tends to increase, the present invention is effective.

  In addition, the indenter lockable portion formed on the sintered part A may not be the lower edge of the part. For example, when there is a stepped portion on the side surface of the component, the indenter can be locked to the edge of the stepped portion.

  The sizing mold of the present invention and the sizing apparatus using the same can be used for dimensional correction of sintered parts other than the bearing cap. Even if it is not a bearing cap, the sizing of a sintered part with a concave or convex surface corrected by the lower punch may cause a lower punch detachment failure when the sized sintered part is removed from the mold. However, by applying the present invention, the problem can be solved and continuous sizing work can be performed.

DESCRIPTION OF SYMBOLS 1 Sizing die 2 Die 2a Molding hole 3 Lower punch 3a Molding surface 4 Core rod 5 Upper punch 6 Die plate 7,11 Connecting rod 8 Fixed plate 9 Lower punch holder 9a Recess 10 Elastic member 12 Movable plate 13 Lower punch presser 14 For raising / lowering Actuator 15 Upper ram 16 Spring receiver 20 Turntable 21 Table body 21a Assembly hole 22 Workpiece holding unit 23 Workpiece insertion hole 24 Indenter 24a Ball 24b Spring 24c Adjusting screw g Clearance A Sintered part

Claims (5)

A sizing die for a sintered part that presses the sintered part (A) to be sized with an upper punch (5) and pushes it into the forming hole (2a) of the die (2) to correct the dimensions,
A lower punch holder (9),
A lower punch (3) placed on the lower punch holder (9) and facing the upper punch (5);
A lower punch presser (fitting) to the side surface of the lower punch (3) and having a gap (g) between the lower punch (3) in the axial direction and allowing the lower punch (3) to move in the axial direction. 13)
Furthermore, the metal mold for sizing of sintered parts provided with the elastic member (10) which urges | biases the said lower punch (3) upwards.   The die for sizing a sintered part according to claim 1, wherein the elastic member (10) is a spring.   The die for sizing a sintered part according to claim 1 or 2, wherein the elastic member (10) is disposed between the lower punch (3) and the lower punch holder (9).   The die for sizing a sintered part according to any one of claims 1 to 3, wherein the lower punch (3) includes a molding surface (3a) that is convex or concave upward. Sizing mold (1) according to any of claims 1 to 4,
It has a turntable (20) for carrying in and carrying out the sintered part (A) to be sized to the press part,
The work table insertion hole (23) disposed above the die (2) for the sizing mold and the sintered part (A) inserted into the hole are pressed from the side to the turntable (20). A sizing device for a sintered part provided with an indenter (24) capable of appearing and retracting in a holding pressing direction.

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