JP2006144050A - Method for manufacturing molded product, molding method, and mold - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a molded product manufacturing method, a molding method, and a molding die capable of easily and inexpensively molding a plurality of types of molded products having different dimensions or shapes with a simple configuration.
A molding die is for molding a plurality of types of molded products W having different dimensions or shapes, and a die 1 for molding an outer peripheral surface Wa of the molded product W, and upper and lower end surfaces Wb, Wc of the molded product W. Are selected as the lower punch 2 and the upper punch 3, the outer core rod 40 that molds the inner peripheral surface Wd of the molded product W, and the inner core rod 41 that is disposed inside the outer core rod 40. A plurality of inner core rod groups having different rigidity. Since the inner core rod 41 having a predetermined rigidity allows a predetermined amount of elastic deformation inward in the radial direction of the outer core rod 40 and backs up, the inner teeth Wd are accurately molded with a set size. Figure 2

Description

  The present invention relates to a method of manufacturing a molded product, a molding method, and a mold, and more specifically, a method of manufacturing a molded product, a size or a method of molding a plurality of types of molded products having different sizes or shapes by a die, a punch, and a core rod. The present invention relates to a molding method for molding a plurality of types of molded products having different shapes and a mold for molding a plurality of types of molded products having different sizes or shapes.

For example, cylindrical sintered parts having teeth such as splines, internal gears, and external gears made by powder metallurgy are generally corrected in shape and size by a sizing die. Patent Document 1 is known as a sizing method for such a cylindrical sintered part.
Patent Document 1 shows a structure having a ridge at one end of a boss portion and a stepped helical spline on the inner side (inner peripheral surface) of the boss portion as a sintered part. In order to size such a sintered part, a die for correcting the outer diameter part (outer peripheral surface) of the boss part, a core rod for correcting the inner diameter side (inner peripheral surface) of the sintered part, A sizing die comprising a lower punch for correcting the lower end surface of the bonded part and an upper punch for correcting the upper end surface of the sintered part is disclosed. Patent Document 1 describes that the sintered part is fitted on the upper part of the core rod, is pushed down together with the core rod by the upper punch, is pushed into the die, and is pressed from above and below by the upper and lower punches (page 3). Upper left column line 20 to upper right column line 4).
The forging die also has a die, a punch, and a core rod, as in the sizing die, and uses the forging die to press a sintered part that becomes a molded product to perform plastic deformation. And processing into a molded product having a predetermined shape has been conventionally performed.
The core rod in such a conventional mold generally has a shape for forming the inner peripheral surface of the molded product into a predetermined shape on its outer peripheral surface, and has a hole for inserting a tightening bolt in the central axis direction. Is formed. And the conventional core rod is comprised integrally, and several were prepared according to dimensions, such as the shape and magnitude | size of the internal peripheral surface which a molded article shape | molds, and the precision (in the case of sizing).

Japanese Patent Laid-Open No. 3-197604

  However, in order to accurately mold the inner peripheral surface of the molded product, the core rod is made of a relatively expensive material such as cemented carbide. The core rod is integrally formed as in the past, and the molded product is molded. There is a problem in that a plurality of the inner peripheral surfaces must be prepared according to the shape and dimensions of the inner peripheral surface, which is costly.

  The present invention has been made in view of the above-described problems, and has a simple configuration, a molded product manufacturing method, a molding method, and a molded product capable of easily and inexpensively molding a plurality of types of molded products having different dimensions or shapes, and An object is to provide a mold.

The invention according to the method for manufacturing a molded product according to claim 1 is a method for manufacturing a molded product in which a plurality of types of molded products having different dimensions or shapes are formed by a die, a punch, and a core rod in order to achieve the above object. The core rod is composed of an outer core rod that molds the inner peripheral surface of the molded product, and one inner core rod that is arranged inside the outer core rod, thereby molding a molded product having one dimension or shape, In place of the one inner core rod, another inner core rod having different rigidity is arranged inside the outer core rod to constitute the core rod, and a molded product having another size or shape is formed. Is.
In order to achieve the above object, the invention according to claim 2 is a molding method for molding a plurality of types of molded products having different dimensions or shapes, and a die for molding the outer peripheral surface of the molded product, and the molded product A molded product is formed by a punch for molding the end surface of the outer core rod, an outer core rod for molding the inner peripheral surface of the molded product, and an inner core rod disposed inside the outer core rod, and the rigidity of the inner core rod is determined by the dimensions of the molded product. Or it is made to differ according to a shape.
In order to achieve the above object, the invention according to claim 3 is a molding die for molding a plurality of types of molded products having different dimensions or shapes, and a die for molding the outer peripheral surface of the molded product, and the molded product. A group of a plurality of inner core rods having different stiffnesses, one of which is selected as an inner core rod disposed on the inner side of the outer core rod; , Characterized by having.

According to the first aspect of the present invention, a core rod is constituted by an outer core rod that molds the inner peripheral surface of the molded product and one inner core rod that is disposed inside the outer core rod, and the core rod, the die, and the punch are used. A molded product having one dimension or shape is formed. In the case of manufacturing a molded product having a different size or shape, the core rod is constituted by arranging another inner core rod having different rigidity inside the outer core rod instead of the one inner core rod. When the molded product is pressed by the punch, its end surface is formed into a predetermined shape, and the material flows in the radial direction. The outer peripheral surface is formed by a die and the inner peripheral surface is formed by an outer core rod. At this time, the inner peripheral surface of the molded product presses the outer core rod radially inward. Then, the one inner core rod having a predetermined rigidity arranged inside the outer core rod allows elastic deformation of the outer core rod inward in the radial direction and backs up, and in this state, one shape or dimension is achieved by the outer core rod. A molded product molded on the inner peripheral surface of the is manufactured. And when manufacturing the molded article from which a dimension or a shape differs, it replaces with one inner core rod, and a core rod is comprised by arrange | positioning the other inner core rod from which rigidity differs in the inner side of an outer core rod. When molding the molded product, the inner peripheral surface of the molded product presses the outer core rod radially inward, but the rigidity of the inner core rod arranged on the inner side is different. Since the elastic deformation and the backup thereof are also different, a molded product having inner peripheral surfaces with different dimensions or shapes is manufactured.
In the invention of claim 2, the outer peripheral surface of the molded product is molded by a die, the end surface of the molded product is molded by a punch, and the inner core rod is arranged in accordance with the size or shape of the molded product. Mold the circumference. At this time, the inner peripheral surface of the molded product presses the outer core rod radially inward. Then, the one inner core rod having a predetermined rigidity arranged inside the outer core rod allows elastic deformation of the outer core rod inward in the radial direction and backs up, and in this state, one shape or dimension is achieved by the outer core rod. A molded product molded on the inner peripheral surface of the is molded. And when shape | molding the molded article from which a dimension or a shape differs, the inner core rod of rigidity which changes with the dimension or shape of a molded article is arrange | positioned inside an outer core rod. Since the elastic deformation inward in the radial direction of the outer core rod allowed and backed up by the inner core rod changes, molded products having different dimensions or shapes are formed.
According to the invention of claim 3, a rigid inner core rod corresponding to the inner peripheral surface of the molded product to be molded is selected from a group of a plurality of inner core rods having different rigidity, and the selected inner core rod is selected as the outer core rod. The outer peripheral surface of the molded product is formed with a die, the outer surface of the molded product is molded with a die, the end surface of the molded product is molded with a punch, and the inner core rod is arranged according to the size or shape of the molded product. Mold the circumference. At this time, the inner peripheral surface of the molded product presses the outer core rod radially inward. Then, with the inner core rod having a predetermined rigidity arranged inside the outer core rod, the outer core rod is allowed to elastically deform radially inward and backed up, and the outer peripheral surface is backed up by the outer core rod. A molded product formed into one shape or size is formed. And when shape | molding the molded article from which a dimension or a shape differs, the inner core rod from which rigidity differs according to the dimension or shape of a molded article is selected from the group of an inner core rod, and it arrange | positions inside an outer core rod. The inner core rod changes the elastic deformation of the outer core rod, which is allowed and backed up, inward in the radial direction, so that molded products having different dimensions or shapes are formed.

According to invention of Claim 1, a core rod is comprised by the outer core rod which shape | molds the internal peripheral surface of a molded article, and the one inner core rod arrange | positioned inside this outer core rod, One dimension or shape A molded article having other dimensions or shapes by forming a molded article having a core rod by arranging another inner core rod having different rigidity inside the outer core rod instead of the one inner core rod. Therefore, it is possible to provide a method for manufacturing a molded product that can easily mold a plurality of types of molded products having different dimensions or shapes at a low cost with a simple configuration.
According to the invention of claim 2, the die for forming the outer peripheral surface of the molded product, the punch for forming the end surface of the molded product, the outer core rod for forming the inner peripheral surface of the molded product, and the inner core rod are disposed inside the outer core rod. The inner core rod is used to form a molded product, and the rigidity of the inner core rod is varied according to the size or shape of the molded product, so a plurality of types of molded products having different sizes or shapes can be easily and inexpensively. It is possible to provide a molding method that can be molded by the above method.
According to the invention of claim 3, the die for forming the outer peripheral surface of the molded product, the punch for forming the end surface of the molded product, the outer core rod for forming the inner peripheral surface of the molded product, and the inner core rod are disposed inside the outer core rod. By having a group of a plurality of inner core rods having different rigidity selected as one of the inner core rods to be selected, a plurality of types of molded products having different dimensions or shapes can be easily and inexpensively formed with a simple configuration. The mold which can be provided can be provided.

First, an embodiment of a mold according to the present invention will be described in detail with reference to FIGS. Note that, in different embodiments, the same or corresponding parts are denoted by the same reference numerals and description thereof is omitted.
The molding die of the present invention molds a plurality of types of molded products W having different outlines, dimensions, or shapes, and includes a die 1 for molding the outer peripheral surface Wa of the molded product W, and upper and lower end surfaces Wb of the molded product W, One is selected as the lower punch 2 and the upper punch 3 that respectively mold Wc, the outer core rod 40 that molds the inner peripheral surface Wd of the molded product W, and the inner core rod 41 that is disposed inside the outer core rod 40. A plurality of inner core rod groups having different rigidity.
In this embodiment, the molded product W is a sintered part molded by powder metallurgy, and has outer teeth Wa formed on the outer peripheral surface and inner teeth Wd formed on the inner peripheral surface. Therefore, the case where the mold is a sizing mold for correcting the internal teeth Wd will be described.

The die 1 has a thickness that allows the molded product W to be accommodated therein and can be pressurized by the lower punch 2 and the upper punch 3, and is fixed by a die holder. On the inner peripheral surface of the die 1, an external tooth fixing surface 1 a corresponding to the uncorrected or corrected external tooth Wa of the sintered part W is formed.
The lower punch 2 is supported by a knockout plate 21 that is moved up and down by a knockout pin 20 and a spacer 22 placed on the knockout plate 21 so as to be moved up and down. An outer peripheral surface of the lower punch 2 is formed with an engaging surface 2a that is slidably engaged with the external tooth fixing surface 1a of the die 1, and the inner peripheral surface thereof is engaged with the correction surface 4a of the core rod 4. The meshing surface 2b to be formed is formed. A molding surface 2 c is formed on the upper surface of the lower punch 2 to press and mold the lower end surface Wb of the sintered part W.
The upper punch 3 is supported by a press ram so as to be movable up and down. On the outer peripheral surface of the upper punch 3, a meshing surface 3 a is formed which can slide in a state of meshing with the external tooth fixing surface 1 a of the die 1, and the correction surface 4 a of the core rod 4 is formed on the inner peripheral surface thereof. A meshing surface 3b that is slidable in a meshed state is formed. A molding surface 3c is formed on the lower surface of the upper punch 3 to press and mold the upper end surface Wc of the sintered part W.

As shown in FIGS. 2 and 3, the outer core rod 40 and the inner core rod 41 constitute the core rod 4. The core rod 4 is disposed in the die 1 and has an axial length that can correct the internal teeth Wd of the molded product W. On the outer peripheral surface of the outer core rod 40, a correction surface 4a for correcting the inner teeth Wd of the sintered part W is formed. The outer core rod 40 is made of a carbide material. On the other hand, a plurality of inner core rods 41 made of materials having different rigidity are prepared to constitute a group of inner core rods. Each inner core rod 41 is set so that the outer diameter of the inner core rod 41 is fitted to the outer core rod 40 with a predetermined clearance, and the inner diameter of the central axial direction hole 41a can be inserted into a tightening bolt 42 described later. Is formed. The outer diameter of the core supporter 43 is a diameter that can support the inner core rod 41 and the outer core rod 40, and is set smaller than the tooth gap of the correction surface 40 a of the outer core rod 40. Further, the radial size of the head 42a of the tightening bolt 42 is set to be larger than the inner diameter of the outer core rod 40 and smaller than the tooth groove of the correction surface 40a of the outer core rod 40, as shown in FIG. Has been. The core rod 4 is configured by an outer core rod 40 being externally fitted to an inner core rod 41 having a predetermined rigidity. A tightening bolt 42 is inserted into the central shaft hole 41 a of the inner core rod 41 and is screwed onto the upper end surface of the core supporter 43. By being combined, the core supporter 43 is fixed.
The external tooth fixing surface 1a of the die 1 and the meshing surface 2a of the lower punch 2, the meshing surface 2b of the lower punch 2 and the correction surface 4a of the outer core rod 40 are slidably meshed, and the meshing surface 3a of the upper punch 3 is slidably meshed. The die 1, the lower punch 2, the upper punch 3, and the core rod 4 so that the external tooth fixing surface 1 a of the die 1, the meshing surface 3 b of the upper punch 3 and the correction surface 4 a of the outer core rod 40 are meshed and slid. Are arranged such that each central axis coincides with the central axis C.

Next, the molding method and the manufacturing method of the molded product according to the present invention will be described together with the operation of the molding die when the inner peripheral surface Wd of the molded product W is molded using the molding die configured as described above. .
The molding method of the present invention is to mold a plurality of types of molded products W having different outlines, dimensions or shapes, and a die 1 for molding the outer peripheral surface Wa of the molded product W, and upper and lower end surfaces Wb of the molded product W, The molded product is molded by the lower punch 2 and the upper punch 3 for molding Wc, the outer core rod 40 for molding the inner peripheral surface Wd of the molded product W, and the inner core rod 41 disposed inside the outer core rod 40. The rigidity of the inner core rod 41 is selected to be different depending on the size or shape of the molded product W.
The method for manufacturing a molded product W according to the present invention is to roughly form a plurality of types of molded products W having different dimensions or shapes by using a die 1 and a lower punch 2 and an upper punch 3 and a core rod 4. 4 is composed of an outer core rod 40 that molds the inner peripheral surface Wd of the molded product W and one inner core rod 41 that is arranged inside the outer core rod 40, and the inner peripheral surface Wd has one dimension or A molded product W having a shape is formed, and instead of this one inner core rod 41, another inner core rod 41 having different rigidity is arranged inside the outer core rod 40 to constitute the core rod 4, and the inner peripheral surface Wd Is for molding a molded product W having other dimensions or shapes.
In this embodiment as well, the molded product W is a sintered part molded by powder metallurgy, and has outer teeth Wa formed on the outer peripheral surface and inner teeth Wd formed on the inner peripheral surface. In particular, the case where the molded product W in which sizing for correcting the internal teeth Wd is performed will be described.

  When correcting the internal teeth Wd of the sintered part W, first, one having a rigidity corresponding to the diameter of the internal tooth Wd to be corrected of the sintered part W is selected from the group of inner core rods 41 having different rigidity. The core supporter 43 is selected by fitting the outer core rod 40 to the inner core rod 41 and inserting the tightening bolt 42 into the central shaft hole 41a of the inner core rod 41 and screwing it into the upper end surface of the core supporter 43. The core rod 4 fixed on the top is constituted. Then, in a state where the phases of the external teeth Wa of the sintered part W and the external tooth fixing surface 1a of the die 1 are aligned with each other, the sintered part W is placed on the die 1 and driven upward by driving the press ram. The punch 3 is lowered. Thereby, the molding surface 3c of the upper punch 3 presses the upper end surface Wc of the sintered part W to press-fit the sintered part W into the die 1, and the meshing surface 3a of the upper punch 3 is fixed to the outside of the die 1. It meshes with the surface 1a. When the upper punch 3 is further lowered, the inner tooth Wd of the sintered part W meshes with the correction surface 4a of the outer core rod 40, and is added between the molding surface 2c of the lower punch 2 and the molding surface 3c of the upper punch 3. Pressed. At this time, the sintered part W is pressed between the molding surfaces 2c and 3c of the lower punch 2 and the upper punch 3 so that the lower end surface Wb and the upper end surface Wc are each molded into a predetermined shape. The material flows in the radial direction, the outer teeth Wa are fixed by the outer tooth fixing surface 1a of the die 1, and the inner teeth Wd are pressed against the correction surface 4a of the outer core rod 40 and corrected according to the shape. It becomes. At this time, the inner core rod 41 having a predetermined rigidity fitted in the outer core rod 40 backs up by allowing a predetermined amount of elastic deformation of the outer core rod 40 radially inward, so that the inner teeth Wd are set as set. With this size, it will be accurately molded.

  Here, a specific embodiment of the core rod 4 will be described with reference to FIGS. In this embodiment, the tip diameter φA on the correction surface 4a of the outer core rod 40 is 40 mm, the inner diameter of the outer core rod 40 and the outer diameter φB of the inner core rod 41 fitted therein are 25 mm, and the inner diameter φC of the inner core rod 41 is 13 mm. The clearance between the outer core rod 40 and each inner core rod 41 is assumed to be 0.005 to 0.015 mm. As the plurality of inner core rods 41, six types having Young's modulus E of 64 GPa, 58 GPa, 54 GPa, 46 GPa, 23 GPa, and 21 GPa are prepared, and the outer core rod 40 having a Young's modulus of 46 GPa is used. . On the other hand, the pressure P applied between the upper punch 3 and the lower punch 2 and the material flows in the radial direction to cause the core rod 4 to receive a force P on the radially inner side of 500 MPa. FIG. 4 is a graph showing the deformation amount (vertical axis) calculated for the tooth tip diameter on the correction surface 4a of the outer core rod 40 with respect to each inner core rod 41 (horizontal axis) under such conditions. As is apparent from FIG. 4, by adopting the inner core rod 41 having a different stiffness between Young's modulus E of 64 GPa and 21 GPa, the deformation amount at the tooth tip is reduced by about 0 with the single outer core rod 40. In the range of .014 to 0.044 mm, that is, the molding (correction) of the internal teeth Wd of the sintered part W can be changed by about 0.03 mm at the maximum.

  Since the present invention is as described above, an inner core rod 41 having an appropriate rigidity is arranged inside the outer core rod 40 according to the molded product W to be manufactured to constitute the core rod, and the core supporter 43 By tightening and fixing to the upper end, it is possible to cope with the size or accuracy (namely, shape or size) of correction or molding of the inner peripheral surface Wd of a different molded product W. Therefore, it is not necessary to prepare the entire core rod 4 for every size or precision of correction or molding of the inner peripheral surface Wd of the molded product W as in the prior art, and the outer core rod 40 is used in common for each inner core rod 41. Cost can be reduced. Further, even when the correction surface 4a needs to be replaced due to wear or the like, the inner core rod 41 is not worn, and only the outer core rod 40 needs to be replaced, thereby reducing the cost. it can.

  When the sintered part is formed into a predetermined shape, the upper punch 3 is moved upward and retracted from the die 1, and then the knockout pin 20 is driven upward to lower the punch through the knockout plate 21 and the spacer 22. 2 is moved upward to push the sintered part W out of the die 1.

  The present invention is not limited to the above-described embodiment. The diameter size and Young's modulus of the outer core rod 40 and the inner core rod 41, the number (group) of inner core rods 41 to be prepared, and the like can be set as necessary. The present invention is not limited to the sizing mold and the molding method, but can be applied to other processes such as forging. Further, the inner peripheral surface of the molded product may be not only the inner teeth Wd but also an inner spline, and may be not only a spur gear but also a helical gear.

1 is an overall cross-sectional view showing an embodiment of a mold according to the present invention. 1 is a cross-sectional view of a core rod constructed in accordance with the present invention. 1 is an end view of a core rod constructed in accordance with the present invention. FIG. It is a graph which shows the relationship of the deformation amount of the outer core rod with respect to the different rigidity of an inner core rod.

Explanation of symbols

W: Sintered part (molded product), Wa: external tooth (outer peripheral surface), Wb, Wc = end surface, Wd: internal tooth (inner peripheral surface), 1: die, 2: lower punch, 3: upper punch, 4 : Core rod, 4a: Correction surface, 40: Outer core rod, 41: Inner core rod

Claims (3)

A method of manufacturing a molded product, in which a plurality of types of molded products having different dimensions or shapes are formed by a die, a punch, and a core rod,
The core rod is composed of an outer core rod that molds the inner peripheral surface of the molded product, and one inner core rod that is arranged inside the outer core rod, thereby molding a molded product having one dimension or shape,
In place of the one inner core rod, another inner core rod having different rigidity is arranged inside the outer core rod to constitute the core rod, and a molded product having another size or shape is formed. Manufacturing method of molded products. A molding method for molding a plurality of types of molded products having different dimensions or shapes,
A die for molding the outer peripheral surface of the molded product;
A punch for molding the end face of the molded product,
An outer core rod for molding the inner peripheral surface of the molded product;
An inner core rod disposed inside the outer core rod;
The molded product is molded by
A molding method characterized by varying the rigidity of the inner core rod according to the size or shape of a molded product. A mold for molding a plurality of types of molded articles having different dimensions or shapes,
A die for molding the outer peripheral surface of the molded product;
A punch for molding the end face of the molded product,
An outer core rod for molding the inner peripheral surface of the molded product;
A group of a plurality of inner core rods having different rigidity selected as one of the inner core rods arranged inside the outer core rod;
A mold having the following characteristics.

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