JP6575410B2 - Green compact manufacturing method - Google Patents

Description

The present invention relates to a method of manufacturing a green compact using the powder powder press forming apparatus.

2. Description of the Related Art Conventionally, a powder press molding apparatus that molds a green compact by pressing a powder of metal, carbon, ceramic, or the like is known. In general, a powder press molding apparatus feeds powder to a cavity formed in a die plate and a lower punch, and then pressurizes the powder in the cavity with a punch fixed to the ram to form a green compact.
The powder press molding apparatus described in Patent Document 1 supplies powder to a cavity formed on a rotary table, rotates the rotary table by a predetermined angle, positions the cavity directly under the punch, inserts the punch into the cavity, and powder Is pressure-molded. Thereby, this powder press molding apparatus has shortened cycle time.

JP 2009-255112 A

However, in the powder press molding apparatus described in Patent Document 1, since the cavity rotates together with the rotary table, the powder supplied to the cavity is subjected to gravitational acceleration. As a result, if the density of the powder in the cavity is biased, the density distribution or dimensional accuracy of the green compact may be deteriorated when the powder is pressed by a punch.
The present invention has been made in view of the above-described problems, and provides a method for producing a green compact that can shorten the cycle time while improving the density distribution uniformity or dimensional accuracy of the green compact. For the purpose.

The present invention is a method for producing a green compact using a powder press molding apparatus. The powder press molding apparatus includes a die plate, a ram, a powder feeder, a punch unit, a lower punch, a feeder moving unit, and a punch moving unit.
The die plate has a cavity capable of forming a green compact. The ram moves in a direction toward and away from the die plate. The powder feeder supplies powder to the cavity in a state where the ram and the die plate are separated from each other by a predetermined distance.
Punching unit punches, that having a support and biasing member. The punch is inserted into the cavity as the ram approaches the die plate. The support portion supports the punch so as to be able to reciprocate in the moving direction of the ram. The biasing member biases the punch toward the ram side with respect to the support portion so that the punch comes out of the cavity. The punch unit is movable along a plane that intersects the moving direction of the ram while the punch is out of the cavity.

The lower punch is provided to be movable relative to the die plate on the side opposite to the opening where the punch is inserted into the cavity, and forms a cavity together with the die plate. The feeder moving unit moves the powder feeder along a plane that intersects the moving direction of the ram. The punch moving unit moves the punch unit along a plane intersecting the moving direction of the ram.

The method for producing a green compact of the present invention includes first to fifth steps. In the first step, the powder feeder moved to the upper side of the opening of the cavity by the operation of the feeder moving unit supplies the powder to the cavity. In the second step, the punch unit moves onto the cavity. In the third step, the ram is brought close to the die plate and the punch is inserted into the cavity. In the fourth step, the ram moves away from the die plate, and the punch inserted into the cavity is removed from the cavity by the urging force of the urging member, and then the punch unit is returned to the original position by the operation of the punch moving unit. . In the fifth step, the die plate moves relative to the lower punch in the direction opposite to the cavity, and the lower punch pushes up the green compact from the opening of the cavity, thereby taking out the green compact from the cavity.

In the green compact manufacturing method of the present invention, since the cavity can be fixed in a predetermined position, the powder in the cavity can be pressed while the density of the powder in the cavity is kept uniform. . Thereby, the manufacturing method of the green compact of this invention can shape | mold the green compact which has uniform density distribution. The green compact manufacturing method of the present invention can mold a green compact with relatively high dimensional accuracy.

In addition, the powder press molding apparatus used in the green compact manufacturing method of the present invention supplies powder from the powder feeder to the cavity with the gap between the ram and the die plate exceeding the height of the powder feeder. Is possible. Therefore, the powder press molding apparatus using this punch unit can shorten the moving distance of the ram, so that the cycle time can be shortened.
In addition, since the punch unit can move from the cavity along a plane that intersects the moving direction of the ram, the powder press molding apparatus can fix the cavity at a predetermined position. Therefore, unlike the powder press molding apparatus of Patent Document 1 described above, the powder density in the cavity is kept uniform without the powder in the cavity being biased by gravitational acceleration. Therefore, by using this punch unit, the powder press molding apparatus can improve the uniformity or dimensional accuracy of the density distribution of the green compact.

It is a schematic diagram of the powder press molding apparatus by 1st Embodiment of this invention. It is a schematic diagram of the punch unit of 1st Embodiment. It is a top view of the III direction of FIG. It is a flowchart of the manufacturing method of the green compact by 1st Embodiment of this invention. It is explanatory drawing of operation | movement of the powder press molding apparatus by 1st Embodiment. It is explanatory drawing of operation | movement of the powder press molding apparatus by 1st Embodiment. It is explanatory drawing of operation | movement of the powder press molding apparatus by 1st Embodiment. It is explanatory drawing of operation | movement of the powder press molding apparatus by 1st Embodiment. It is explanatory drawing of operation | movement of the powder press molding apparatus by 1st Embodiment. It is a schematic diagram of the powder press molding apparatus by 2nd Embodiment of this invention.

Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings. Note that, in a plurality of embodiments, substantially the same configuration is denoted by the same reference numeral, and description thereof is omitted.
(First embodiment)
A first embodiment of the present invention is shown in FIGS. The powder press molding apparatus 1 of 1st Embodiment shape | molds a green compact. Here, the “green compact” is formed, for example, by pressing a powder 2 such as a metal, carbon, or ceramic, into a predetermined shape. Alternatively, for example, a mixture of a lubricant, a binder, or the like and the powder may be pressed into a predetermined shape.

<Configuration of powder press molding equipment>
First, the configuration of the powder press molding apparatus 1 will be described.
As shown in FIG. 1, the powder press molding apparatus 1 includes a base 10, a lower punch 11, a die plate 13, a ram 14, a powder feeder 20, a punch unit 30, and the like.
A lower punch 11 is fixed to the base 10. The die plate 13 provided on the upper side of the base 10 together with the lower punch 11 forms a cavity 15 in which a green compact is formed. As shown in FIG. 8, the die plate 13 is movable relative to the base 10 and the lower punch 11. By bringing the die plate 13 and the base 10 close to each other, the green compact 3 formed in the cavity 15 can be taken out from the opening 16 on the cavity 15 opposite to the lower punch 11.

The ram 14 is provided on the opposite side of the lower punch 11 across the die plate 13. As shown in FIGS. 7 and 8, the ram 14 can be moved in a direction toward and away from the die plate 13 by a driving device such as a hydraulic cylinder (not shown).
In the present embodiment, the direction in which the ram 14 moves is defined as a Z axis, and three-dimensional orthogonal coordinates are defined by an X axis and a Y axis perpendicular to the Z axis and perpendicular to each other.

  The powder feeder 20 stores the powder 2 such as metal, carbon or ceramic inside the housing 21. Alternatively, the powder 2 stored by the powder feeder 20 may be obtained by kneading a metal or the like with a binder. As shown in FIG. 5, the powder feeder 20 supplies the powder 2 by gravity to the cavity 15 from the opening 16 of the cavity 15. Therefore, the volume of the casing 21 of the powder feeder 20 is set to about several times the volume of the cavity 15 in consideration of the fluidity of the powder 2 due to the frictional force between the particles of the powder 2 and gravity. . Thereby, the powder feeder 20 can supply the powder 2 in the cavity 15 with a uniform density. The powder feeder 20 is supplied with the powder 2 continuously or intermittently from a hose not shown.

  A feeder moving unit 22 is connected to the casing 21 of the powder feeder 20. The feeder moving unit 22 is, for example, a hydraulic cylinder, and moves the powder feeder 20 along the XY plane. Thereby, the powder feeder 20 can move between the ram 14 and the die plate 13 along the XY plane.

As shown in FIGS. 1 to 3, the punch unit 30 includes a punch 31, a support portion 32, a first connecting portion 33, a second connecting portion 34, a spring 35 as a biasing member, a first cam follower 36, and a second cam follower. 37 and the like.
The punch 31 has a shaft portion 311 formed in a column shape and an insertion portion 312 formed on the shaft portion 311 on the die plate 13 side. The shaft portion 311 of the punch 31 is supported by an inner wall of a sliding hole 321 formed in the support portion 32 so as to be able to reciprocate in the Z-axis direction. In addition, the shape of the inner wall of the sliding hole 321 viewed from the Z direction is a non-circular shape, and the shaft portion 311 has a shape corresponding to the inner wall of the sliding hole 321, thereby positioning the punch 31 in the rotational direction. Also good.

The shape of the insertion portion 312 of the punch 31 corresponds to the shape of the cavity 15. Thereby, the insertion portion 312 can be inserted into the cavity 15 and can pressurize the powder 2 supplied to the cavity 15. Note that the shape of the inner wall of the cavity 15 and the shape of the insertion portion 312 of the punch 31 corresponding to the shape seen from the Z direction are not limited to the circular shape shown in FIG. 3, but are arbitrarily set according to the green compact shape. Is.
A contact portion 38 is fixed to the end portion of the punch 31 on the ram 14 side by a bolt 39. As shown in FIG. 6, when the ram 14 moves in a direction approaching the die plate 13, the contact portion 38 is pressed by the ram 14, and the insertion portion 312 of the punch 31 is inserted into the cavity 15.

  As shown in FIGS. 2 and 3, the first coupling portion 33 is formed in a cylindrical shape, for example, and is fixed to the contact portion 38. On the other hand, the second connecting portion 34 is formed in a columnar shape, for example, and is fixed to the support portion 32. The second connecting portion 34 is inserted inside the first connecting portion 33 and is in sliding contact with the inner wall of the first connecting portion 33. The first connecting part 33 and the second connecting part 34 are relatively movable in the Z-axis direction, and restrict displacement of the contact part 38 and the support part 32 in a direction intersecting the Z-axis. . In addition, the 1st connection part 33 and the 2nd connection part 34 should just be connected so that relative movement mutually is possible in the Z-axis direction, and those shapes can be set arbitrarily.

  One end of the spring 35 is locked to the contact portion 38, and the other end is locked to the support portion 32, and the punch 31 is biased toward the ram 14 toward the support portion 32. As shown in FIG. 8, when the ram 14 moves away from the cavity 15, the punch 31 can come out of the cavity 15 by the biasing force of the spring 35.

  As shown in FIGS. 1 to 3, a plurality of first cam followers 36 and a plurality of second cam followers 37 are attached to the support portion 32. Corresponding to these, the powder press molding apparatus 1 includes a lower guide rail 41 provided on the die plate 13 side of the support portion 32 and a horizontal guide rail 42 provided on the left and right of the support portion 32 in the Y-axis direction. ing. The lower guide rail 41 and the lateral guide rail 42 guide the punch unit 30 along the XY plane. In addition, the lower guide rail 41 and the horizontal guide rail 42 may be comprised from a separate member, respectively, and may be comprised integrally. The lower guide rail 41 and the lateral guide rail 42 correspond to an example of a “guide rail” described in the claims.

  The plurality of first cam followers 36 are movable in the X-axis direction along the lower guide rail 41 and restrict the displacement of the support portion 32 in the Z-axis direction. The plurality of second cam followers 37 are movable in the X-axis direction along the lateral guide rails 42 and restrict displacement of the support portion 32 in the Y-axis direction. Thereby, the 1st cam follower 36 and the 2nd cam follower 37 can determine the locus | trajectory which the punch unit 30 moves along XY plane.

  As shown in FIG. 1, a punch moving unit 43 is connected to the support unit 32 of the punch unit 30. The punch moving unit 43 is, for example, a hydraulic cylinder, and moves the punch unit 30 along the XY plane. Thereby, the punch unit 30 can move along the XY plane between the ram 14 and the die plate 13 in a state where the punch 31 is pulled out of the cavity 15.

  The powder press molding apparatus 1 further includes a stopper 44. The stopper 44 regulates the movement of the punch unit 30 at a position where the punch 31 and the cavity 15 overlap in the Z-axis direction. As shown in FIG. 6, the punch 31 and the cavity 15 overlap in the Z-axis direction in a state where the support portion 32 of the punch unit 30 and the stopper 44 are in contact with each other. When the ram 14 is lowered in this state, the punch 31 is inserted into the cavity 15 and can pressurize the powder 2.

<Operation of powder press molding equipment>
Next, press working of the powder 2 using this powder press molding apparatus 1 will be described. FIG. 4 shows a flowchart of the pressing process of the powder 2 as the “green compact manufacturing method” according to the first embodiment.
In the powder press molding apparatus 1 before performing the pressing process of the powder 2, as shown in FIG. 5, the ram 14 and the die plate 13 are in a state of being separated with an interval through which the powder feeder 20 can pass. Yes.
In a step (hereinafter simply referred to as “S”) 101 as a “first process”, the powder 2 is supplied to the cavity 15. As shown by the arrow A in FIG. 5, the powder feeder 20 moves to the upper side of the opening 16 of the cavity 15 by the operation of the feeder moving unit 22. At that time, the feeder moving unit 22 moves the powder feeder 20 at a speed at which the powder 2 stored in the powder feeder 20 can be suppressed from being biased to one inner wall of the casing 21 due to gravitational acceleration. Subsequently, the powder feeder 20 supplies the powder 2 from the inside of the housing 21 to the cavity 15 by gravity. Then, the powder feeder 20 returns to the original position by the operation of the feeder moving unit 22.

  Next, in S <b> 102 as the “second step”, the punch unit 30 is moved onto the cavity 15. As shown by an arrow B in FIG. 6, the punch unit 30 moves to the upper side of the opening 16 of the cavity 15 by the operation of the punch moving unit 43. At this time, it is preferable to move the punch unit 30 as fast as possible by the punch moving unit 43 in order to shorten the cycle time. As shown in FIG. 6, the punch 31 and the cavity 15 are overlapped in the Z-axis direction with the support portion 32 of the punch unit 30 and the stopper 44 in contact with each other.

  Next, the punch 31 is inserted into the cavity 15 in S103 as the “third step”. As shown by an arrow C in FIG. 7, when the ram 14 moves in a direction approaching the die plate 13, the contact portion 38 of the punch unit 30 is pressed against the ram 14, and the insertion portion 312 of the punch 31 is inserted into the cavity 15. The When the ram 14 is further lowered, the punch 31 decreases the volume of the cavity 15. Thereby, the powder 2 in the cavity 15 is pressurized and formed into a green compact 3 having the same shape as the cavity 15.

  Next, the punch 31 is removed from the cavity 15 in S104 as the “fourth step”. As shown by arrow D in FIG. 8, when the ram 14 moves away from the die plate 13, the abutting portion 38 rises together with the ram 14 by the urging force of the spring 35, and the punch 31 comes out of the cavity 15. Thereafter, as shown by an arrow E in FIG. 9, the punch unit 30 returns to the original position by the operation of the punch moving unit 43.

  Next, the green compact 3 is taken out from the cavity 15 in S105 as the “fifth step”. As shown by arrow F in FIG. 9, when the die plate 13 moves in a direction approaching the base 10, the lower punch 11 pushes up the green compact 3 from the opening 16 of the cavity 15. Thereby, the green compact 3 is taken out from the cavity 15.

  In the case where the green compact 3 taken out from the cavity 15 is a green body obtained by press-molding a mixture obtained by kneading powder and a binder, for example, a gear is completed through a degreasing process, a sintering process, a cutting process, and the like. It becomes goods. On the other hand, when the green compact 3 taken out from the cavity 15 is obtained by press-molding only the powder 2 such as metal, it is possible to make a finished product such as a dust core as it is.

<Effect>
The punch unit 30 and the powder press molding apparatus 1 of the first embodiment have the following operational effects.
(1) In the first embodiment, the punch unit 30 is movable along the XY plane in a state where the punch 31 has come out of the cavity 15.
Thereby, the powder press molding apparatus 1 provided with the punch unit 30 can move the punch unit 30 and press-mold the powder 2 without moving the cavity 15 to which the powder 2 is supplied. . Therefore, the powder 2 in the cavity 15 is prevented from being biased due to gravitational acceleration. Therefore, the powder press molding apparatus 1 can improve the uniformity or dimensional accuracy of the density distribution of the green compact.

  (2) In the first embodiment, the powder press molding apparatus 1 is configured so that the powder 2 is transferred from the powder feeder 20 to the cavity 15 in a state where the distance between the ram 14 and the die plate 13 is larger than the height of the powder feeder 20. Can be supplied. Therefore, the powder press molding apparatus 1 can shorten the moving distance of the ram 14 in the Z-axis direction, so that the cycle time can be shortened. Moreover, the powder press molding apparatus 1 can reduce the physique and reduce the equipment cost by shortening the moving distance of the ram 14 in the Z-axis direction.

(3) In the first embodiment, the stopper 44 restricts the movement of the punch unit 30 at a position where the punch 31 and the cavity 15 overlap in the Z-axis direction.
Thereby, the powder press molding apparatus 1 can accurately insert the punch 31 into the cavity 15.

(4) In the first embodiment, the lower guide rail 41 and the lateral guide rail 42 guide the punch unit 30 along the XY plane.
Thereby, the powder press molding apparatus 1 can accurately determine the trajectory along which the punch unit 30 moves.

(5) In 1st Embodiment, the 1st cam follower 36 which the punch unit 30 has moves along the lower guide rail 41, and controls the position shift of the support part 32 to a Z-axis direction. The second cam follower 37 moves along the lateral guide rail 42 and restricts the displacement of the support portion 32 in the Y-axis direction.
Thereby, the powder press molding apparatus 1 can prevent the positional deviation of the punch unit 30 and can accurately insert the punch 31 into the cavity 15.

(6) In the first embodiment, the spring 35 included in the punch unit 30 urges the punch 31 toward the ram 14 with respect to the support portion 32.
Thereby, the punch unit 30 can extract the punch 31 from the cavity 15 as the ram 14 is lifted by the urging force of the spring 35. That is, the punch unit 30 has a function of raising and lowering the punch 31.

(7) In 1st Embodiment, the 1st connection part 33 and the 2nd connection part 34 which the punch unit 30 has restrict | limit the position shift of the contact part 38 and the support part 32 in the direction which cross | intersects with respect to a Z-axis. To do.
Thereby, the powder press molding apparatus 1 can accurately insert the punch 31 into the cavity 15.

(8) In the first embodiment, the feeder moving unit 22 moves the powder feeder 20 along the XY plane. The punch moving unit 43 also moves the punch unit 30 along the XY plane.
Thereby, the powder press molding apparatus 1 can move the powder feeder 20 and the punch unit 30 individually. Therefore, it is possible to supply the powder 2 in the cavity 15 with a uniform density by moving the powder feeder 20 at such a speed that the powder 2 in the powder feeder 20 is not biased. Therefore, the powder press molding apparatus 1 can improve the uniformity or dimensional accuracy of the density distribution of the green compact.
Moreover, the powder press molding apparatus 1 can shorten cycle time by moving the punch unit 30 fast.

(9) In the first embodiment, the die plate 13 and the lower punch 11 are relatively movable.
Thereby, the powder press molding apparatus 1 can easily take out the green compact 3 from the cavity 15.

  (10) In the press working of the powder 2 of the first embodiment, in S102, the punch unit 30 moves along the XY plane with the punch 31 coming out of the cavity 15. Thereby, in S103, since the powder 2 can be pressure-formed by the punch unit 30 without moving through the cavity 15 to which the powder 2 is supplied, the green compact 3 can be formed by the gravitational acceleration. Can be prevented from being biased. Therefore, the pressing process of the powder 2 of the first embodiment can form a green compact having a uniform density distribution. In addition, the pressing of the powder 2 of the first embodiment can form a green compact with relatively high dimensional accuracy.

(Second Embodiment)
A second embodiment of the present invention will be described with reference to FIG. FIG. 10 is a schematic view of the powder press molding apparatus 1 as viewed from above the Z axis. In FIG. 10, the ram 14 is indicated by a two-dot chain line.

In the first embodiment described above, the powder feeder 20 and the punch unit 30 move linearly. On the other hand, in the second embodiment, the powder feeder 20 and the punch unit 30 move in an arc shape or a curved shape as indicated by arrows G and H in FIG. Although not shown, in the second embodiment, the lower guide rail and the lateral guide rail extend in an arc shape or a curved shape along the XY plane.
The second embodiment can also provide the same operational effects as the first embodiment.

(Other embodiments)
(1) In the above-described embodiment, the powder feeder 20 and the punch unit 30 are moved along the XY plane perpendicular to the Z axis. On the other hand, in another embodiment, the powder feeder 20 and the punch unit 30 may be configured to move along a plane or a curved surface that intersects the Z axis at an arbitrary angle.

  (2) In the above-described embodiment, the feeder moving unit 22 and the punch moving unit 43 are configured by hydraulic cylinders. On the other hand, in another embodiment, the feeder moving unit 22 and the punch moving unit 43 may be configured by a motor and a ball screw, or a linear actuator.

  (3) In the above-described embodiment, the punch unit 30 has a lifting function using the spring 35 as a biasing member. On the other hand, in another embodiment, the punch unit 30 may have a lifting / lowering function using a hydraulic cylinder or a motor as an urging member.

(4) In the embodiment described above, the movement of the punch unit 30 is regulated by the stopper 44. On the other hand, in another embodiment, the movement amount of the punch unit 30 may be regulated by controlling the operation of the hydraulic cylinder as the punch moving unit 43 using an electronic control device (not shown).
Thus, the present invention is not limited to the above-described embodiment, and can be implemented in various forms without departing from the spirit of the invention.

DESCRIPTION OF SYMBOLS 1 ... Powder press molding apparatus 13 ... Die plate 14 ... Ram 15 ... Cavity 30 ... Punch unit 31 ... Punch 32 ... Support part

Claims (5)

A die plate (13) having a cavity (15) capable of forming a green compact (3);
A ram (14) moving in a direction toward and away from the die plate;
A powder feeder (20) for supplying powder (2) to the cavity in a state where the ram and the die plate are separated by a predetermined distance;
Punch the ram is inserted into the cavity and closer to the die plate (31), before Symbol supporting portion supporting the punch for reciprocating movement in the direction of movement of the ram (32), and, from the punch the cavity An urging member (35) for urging the punch toward the ram side with respect to the support portion so as to come out , and in a state intersecting with the moving direction of the ram in a state where the punch has come out from the cavity. A punch unit (30) movable along,
A lower punch (11) provided on the opposite side of the opening into which the punch is inserted into the cavity so as to be movable relative to the die plate and forming the cavity together with the die plate;
A feeder moving section (22) for moving the powder feeder along a plane intersecting the moving direction of the ram;
A punch moving section (43) for moving the punch unit along a plane intersecting the moving direction of the ram;
A green compact manufacturing method for manufacturing the green compact using a powder press molding apparatus (1) comprising:
A first step in which the powder feeder moved to the upper side of the opening of the cavity by the operation of the feeder moving part supplies powder to the cavity;
A second step of the punch unit is moved over the cavity,
A third step of bringing the ram closer to the die plate and inserting the punch into the cavity;
The ram is moved in a direction away from the die plate, after the punch has been inserted into the cavity had disconnect from the cavity by the biasing force of the biasing member, the basis of the punch unit by the operation of the punch moving section A fourth step of returning to position ;
The die plate moves relative to the lower punch in a direction opposite to the cavity, and the lower punch pushes up the green compact from the opening of the cavity, thereby taking out the green compact from the cavity. 5 steps,
The manufacturing method of the green compact containing this. The powder press molding apparatus is:
Of claim 1, further comprising a stopper (44) for restricting movement of the punch unit in the direction crossing to the direction of movement of the ram at a position and the said punch cavity overlap in the movement direction of the ram A method for producing a green compact . The powder press molding apparatus is:
Method for producing a green compact according to claim 1 or 2 further comprising a guide rail (41, 42) for guiding said punch unit along a plane intersecting with respect to the direction of movement of the ram. The punch unit of the powder press molding apparatus is:
Regulating the positional deviation of the supporting portion of the moving direction of the previous SL ram, the first cam followers moving along the guide rail (36), and, perpendicular to the direction of movement of the ram, and, of the first cam follower The method for manufacturing a green compact according to claim 3 , further comprising a second cam follower (37) that moves along the guide rail while restricting a positional shift of the support portion in a direction perpendicular to a moving direction. The punch unit of the powder press molding apparatus is:
The contact portion provided on the ram side of the front Symbol punch (38), a first connecting portion fixed to the abutment portion (33), and, relative to the direction of movement of the ram relative to the first coupling part A second connecting portion (34) that is movably provided and fixed to the support portion;
The said 1st connection part and the said 2nd connection part are any one of Claim 1 to 4 which controls the position shift with the said contact part and the said support part to the direction which cross | intersects the moving direction of the said ram. The method for producing a green compact according to item.

Images