JP2016000416A - Rotating body-type article manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotating body-type article manufacturing method capable of appropriately obtaining an outer circumferential shape as desired by roller forging.SOLUTION: A rotating body-type article is manufactured by an arrangement step of arranging a material 20 within an inner circumferential surface 111 of an outer circumferential mold 11 that is a ring member, and forming step of pressing the material 20 arranged within the outer circumferential mold 11 from axially both end surfaces while rotating the material 20 in an axial direction of the outer circumferential mold 11 and forming the material 20 into the rotating body-type article. In this case, the outer circumferential mold 11 higher in strength than the material 20 is used. Furthermore, in the forming step, the material 20 is worked by moving a roller 12 rotating about a rotation axis in a direction of crossing a direction of a rotation axis of the material 20 and a rotary table 10 rotating along with the material 20 in a direction of approaching each other while pressing one end surface of the material 20 by the rotary table 10 and compressing the other end surface of the material 20 by a side surface of the roller 12.

Description

  The present invention relates to a method of manufacturing a rotating article by pressing an end face while rotating a material. More specifically, the present invention relates to a method of manufacturing a rotating article that prevents an excessive expansion in the radial direction with respect to the rotation axis of the material so as to obtain an appropriate shape.

  2. Description of the Related Art Conventionally, roller forging has been performed in which a material is rotated while a cylindrical roller that rotates with the material is pressed against the end surface of the material. Patent document 1 is mentioned as an example of such a roller forging technique. In the technique of this document, the end face of the material is expanded in the radial direction by pressing the roller. As a result, tensile stress is generated at the outer peripheral portion of the material to be spread, which is a factor that limits the forming limit. Therefore, in the technique of Patent Document 1, a ring-shaped member is attached to the outer periphery of the material at the time of molding. The ring-shaped member applies a stress opposite to the radial expansion of the material to the outer peripheral portion of the material. In this way, the tensile stress during molding is relaxed and the molding limit is increased.

JP 2011-224605 A

  However, the conventional techniques described above have the following problems. That is, the flow in the diameter increasing direction of the material on the end surface on the roller pressing side is large, and the finished shape does not necessarily have a desired shape. In addition, since an elastic member is used as the ring-shaped member, the expansion of the diameter cannot be controlled sufficiently. For this reason, particularly when a thick material is formed, the end surface on the roller pressing side may be larger than the end surface on the opposite side.

  The present invention has been made to solve the above-described problems of the prior art. That is, an object of the present invention is to provide a method for manufacturing a rotating article that can appropriately obtain a desired outer peripheral shape while performing roller forging.

  A method of manufacturing a rotating article according to an aspect of the present invention includes an arranging step of arranging a material inside an inner peripheral surface of an outer peripheral mold that is a ring-shaped member, and a material disposed inside the outer peripheral mold, And a molding step of rotating the mold around the axial direction of the mold and pressing it from both end faces in the axial direction to form a rotating article. Here, an outer peripheral mold having a strength higher than that of the material is used. In the molding process, one end surface of the material is pressed with a rotating mold that rotates together with the material, and the other end surface of the material and the outer peripheral mold are centered on a rotation axis that intersects the direction of the rotation axis of the material. The material is processed by moving the roller member and the rotary mold in directions close to each other while pressing on the side surface of the rotating roller member.

  In the method for manufacturing a rotating article according to the above aspect, in the molding step, one end surface is molded by the rotary mold while the material rotates around the axial direction, and the other end surface is molded by the roller member. At this time, the flow of the raw material in the diameter increasing direction is regulated by the inner surface of the outer peripheral mold. Thereby, high dimensional accuracy and shape accuracy in the molded product can be obtained by roller forging.

  According to this configuration, there is provided a method of manufacturing a rotating article that can appropriately obtain a desired outer peripheral shape while performing roller forging.

It is sectional drawing explaining the structure of the forge molding apparatus used by embodiment. It is sectional drawing which shows the state which has arrange | positioned the raw material to the forge molding apparatus of FIG. It is sectional drawing which compares and shows the condition before and behind shaping | molding in the forge process by embodiment. It is sectional drawing which shows the area | region strongly received by the forge process by embodiment. It is sectional drawing which compares and shows the condition before and behind shaping | molding in a reference example. It is sectional drawing which shows the area | region strongly received by the forge process by a reference example.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described below in detail with reference to the accompanying drawings. First, an apparatus for manufacturing a rotating article used in this embodiment, that is, a forging apparatus will be described. The manufacturing apparatus according to the present embodiment shown in FIG. 1 is mainly composed of a turntable 10, an outer peripheral mold 11, and a roller 12.

  The turntable 10 has a role as a placing table for placing the material, a role as a rotation transmission member for rotating the material, and a shape of the lower end face in the figure after forming the material while rotating the material. It has a role as a rotating type that regulates. The upper surface 101 of the turntable 10 serves as a mounting table and a lower mold. The turntable 10 is connected to a rotation drive source 16 such as a motor by a shaft 13. As a result, the turntable 10 rotates around a rotation axis L1 in the vertical direction in the figure.

  The outer peripheral mold 11 is a ring-shaped member. The outer peripheral mold 11 is disposed so that the material is positioned inside the inner peripheral surface 111 of the outer peripheral mold 11 when the material is disposed on the turntable 10. The inner peripheral surface 111 of the outer peripheral mold 11 has a role of defining the outer peripheral shape of the molded material. The outer peripheral mold 11 is also movable in the vertical direction (direction parallel to the rotation axis L1) with respect to the height direction position of the turntable 10 (arrow B). Further, the outer peripheral die 11 is provided with a spring 14. The spring 14 urges the outer peripheral die 11 upward in the figure. The position of the outer peripheral mold 11 shown in FIG. 1 is a position raised by the bias of the spring 14. The outer peripheral die 11 is lowered from this position by being pushed down by a roller 12 described later. In a state where the outer peripheral mold 11 is pushed down, at least a part of the turntable 10 is positioned inside the inner peripheral surface 111. In this embodiment, a part of the turntable 10 is already located inside the inner peripheral surface 111 in a state where the outer peripheral mold 11 is not pushed down. When the pressing by the roller 12 is released, the outer peripheral die 11 returns to the position in FIG.

  The roller 12 is a rotating body-shaped member that is rotatably provided around the shaft 15 (rotating axis L2). The direction of the rotation axis L2 is a direction that intersects the rotation axis L1 of the turntable 10. The roller 12 plays the role of defining the shape of the upper end surface in the figure of the material after molding by the side surface as the rotating body. Further, the roller 12 can be moved along the shaft 15 in the vertical direction in FIG. 1 (direction parallel to the rotation axis L1) by an external operation (arrow A). In FIG. 1, two levels of the height direction position of the roller 12 are shown, but the roller 12 can be further pushed down from the lower position among them.

  A horizontal range W where the roller 12 exists will be described. The outer end W <b> 2 of the range W must be outside the inner peripheral surface 111 with respect to the radial direction of the outer peripheral mold 11. This is because it is necessary to contact the upper end surface 112 of the outer peripheral mold 11 when the roller 12 is pushed down. In addition, the inner end W1 of the range W must be located between the rotation axis L1 of the turntable 10 and the outer end W2. That is, the roller 12 does not exist across the rotation axis L1.

  The outer peripheral die 11 is formed of a material having a strength higher than that of the material to be molded. When the material is ordinary carbon steel, the outer peripheral die 11 may be any steel using a cold forging die. The same applies to the turntable 10 and the roller 12.

  In the present embodiment, the rotating article is manufactured by the forging apparatus described above. As an example of the manufactured article, there is a base of a high pressure gas tank for a fuel cell vehicle. The manufacturing method of this embodiment basically has two stages, an arrangement process and a molding process.

(Arrangement process)
In the placement step, the material is placed in the forging apparatus shown in FIG. When placing the material, the roller 12 is raised to the upper position shown in FIG. At this time, the ring-shaped outer peripheral die 11 also rises to the highest position within the moving range. This is because the spring 14 is biased. The position of the outer peripheral mold 11 shown in FIG. 1 is the position at this time. In this state, the material is placed on the upper surface 101 of the turntable 10. The placed material is located inside the inner peripheral surface 111 of the outer peripheral mold 11. The shape of the material to be placed, that is, the shape before forging is roughly disc-shaped. When the material is placed, the roller 12 is lowered until it contacts the upper end surface 112 of the outer peripheral mold 11. This state is shown in FIG. The position of the roller 12 in FIG. 2 is the same as the position of the lower roller 12 in FIG. Further, the position of the outer peripheral mold 11 in FIG. 2 is the same as the position in FIG. That is, at this time, the outer peripheral mold 11 has not been pushed down against the bias of the spring 14.

  At this time, it is desirable that the roller 12 and the upper end surface 112 are in contact with each other. That is, depending on the shape of the material 20 (the shape before forging), the material 20 may come into contact with the roller 12 before the upper end surface 112 when the roller 12 is lowered. In that case, when the roller 12 is lowered, there is a gap between the roller 12 and the upper end surface 112. If so, a part of the material 20 may enter between the roller 12 and the upper end surface 112 and flow in the diameter increasing direction in a later forming step. In that case, the outer peripheral shape of the product is not defined in the expanded portion. If the roller 12 and the upper end surface 112 are in contact with each other when the roller 12 is lowered, there is no such fear. However, this is not an absolute requirement. The gap between the roller 12 and the upper end surface 112 is very small, and after the start of molding, the roller 12 and the upper end surface 112 are in contact with each other before a part of the material 20 enters between the roller 12 and the upper end surface 112. If there is no problem. In this embodiment, as shown in FIG. 2, it is assumed that the roller 12 and the upper end surface 112 are in contact with each other when the roller 12 is lowered.

  In FIG. 2, the material 20 and the inner peripheral surface 111 of the outer peripheral mold 11 are drawn so as to be in contact with each other without any gap, but this is not an essential condition. The size in the radial direction of the material 20 before forging may be just the size relative to the inner peripheral surface 111 or may be smaller than that. The material of the material 20 is not particularly limited as long as it can be plastically processed and has lower strength than the outer peripheral mold 11, the rotary table 10, and the roller 12. Generally, it is a metal such as carbon steel or aluminum. The above is the description of the arrangement process.

(Molding process)
Subsequently, a molding process is performed. In the molding process, first, the material 20 is rotated about its axis. That is, the turntable 10 is rotated by the rotation driving force of the rotation driving source 16. As a result, the material 20 placed on the turntable 10 also rotates around the rotation axis L1 as the turntable 10 rotates. At this time, the outer peripheral mold 11 does not rotate together with the turntable 10. The outer peripheral mold 11 is fixed in the rotational direction. An apparatus configuration in which the outer peripheral mold 11 rotates together with the rotation of the turntable 10 is possible, but this is not the case in this embodiment. Hereinafter, the subsequent processing in the molding process is performed while continuing the rotation of the material 20.

  The roller 12 is further pushed down from the position shown in FIG. 2 while rotating the material 20 in this way. From here on, the roller 12 is pushed down while the outer peripheral die 11 is pushed down and the material 20 is plastically deformed. By further pressing down the roller 12, the interval between the turntable 10 and the roller 12 becomes narrower than the interval shown in FIG.

  For this reason, the lower end surface of the material 20 is pressed by the upper surface 101 of the turntable 10. Further, the upper end surface of the material 20 is pressed by the side surface of the roller 12. At this time, the roller 12 is dragged by the rotation of the material 20 and rotates about its own rotation axis L2. In this way, the material 20 is formed such that the lower end surface follows the shape of the upper surface 101 of the turntable 10, and the portion of the upper end surface outside the inner end W1 of the roller 12 shown in FIG. It will be formed into a shape that follows the shape of the side. Note that the upper end surface of the material 20 appears to be machined only on the right half when viewed in FIG. 2, but in practice, it is machined in all directions around the rotation axis L1. This is because the material 20 rotates about the rotation axis L1. However, the situation near the rotation axis L1 will be described separately.

  FIG. 3 shows the shape of the material 20 after molding. In FIG. 3, the state before molding is shown in the left half, and the state after molding is shown in the right half. Looking at the right half of FIG. 3, it can be seen that the roller 12 and the outer peripheral mold 11 are lowered compared to the left half. And it turns out that the flange part 21 and the boss | hub part 22 are formed in the raw material 20 after shaping | molding. After the molding is completed, the downward pressing of the roller 12 is released and the roller 12 is raised to the position of the upper roller 12 in FIG. As a result, the outer peripheral mold 11 also returns to the position in FIG. What is necessary is just to take out the product (material 20) after shaping | molding from the forge molding apparatus in that state.

  The flange portion 21 is a substantially disk-shaped portion, and is a portion formed by compressing the original material 20 in the thickness direction as a whole. The outer diameter is defined by the inner peripheral surface 111 of the outer peripheral mold 11. The thickness is defined by the shape of the roller 12 and the turntable 10 and the stroke amount of the roller 12 descending from the left half state to the right half state in FIG. For this reason, the precision of the dimension and shape of the flange part 21 is high. The boss portion 22 is a convex portion formed by gathering the portion of the material 20 of the flange portion 21 that is pressed and pushed from the top and bottom to the central portion of the upper end surface of the material 20. The region where the boss portion 22 is formed is a portion of the upper end surface of the flange portion 21 that is not subjected to processing by the roller 12, that is, a region within a range closer to the rotation axis L1 than the inner end W1. The diameter of the boss portion 22 is defined by the position of the inner end W1. Further, the shape of the connecting portion between the flange portion 21 and the boss portion 22 is defined by the shape of the roller 12.

  As described above, in the manufacturing method of the present embodiment, the flow direction during processing of the material 20 is inward. This is because the flow in the diameter expansion direction is restricted by the inner peripheral surface 111 of the outer peripheral mold 11. Thereby, high dimensional accuracy and shape accuracy are obtained. Of the processed material 20, the portion that has been strongly subjected to the processing in this embodiment is a portion indicated by shading in the material 20 in the cross-sectional view of FIG. 4. That is, it is the surface layer vicinity of the upper end surface of the flange portion 21 and the entire boss portion 22. As described above, even this shaded portion hardly flows outward during processing.

  When the material is greatly expanded during processing as in the reference example shown in FIG. 5, there is an outward flow of the material during processing. In the example of FIG. 5, it can be said that the maximum diameter after processing is defined by the lower mold 211, but this is not necessarily the case depending on the shape to be obtained. In the reference example shown in FIG. 6, the portion of the flange 31 is a region formed by an outward flow in the shaded region that is a region that has been subjected to strong processing. In such a flange portion 31, both the outer diameter and thickness are not very accurate. On the other hand, in this embodiment, high accuracy can be obtained as described above.

  As described above in detail, according to the present embodiment, the material 20 is disposed in the outer peripheral die 11 having a higher strength than the raw material 20, and in this state, the roller 12 and the outer peripheral die 11 are brought into contact with each other. Roller forging is performed. Thus, the outer diameter after molding is defined by the inner peripheral surface 111 of the outer peripheral mold 11 while the material flow during processing is mainly directed inward, and high shape accuracy and dimensional accuracy are obtained. Thereby, the manufacturing method of the rotary article | item article which can manufacture the product of the shape difficult to obtain by the conventional forging process is implement | achieved.

  Note that this embodiment is merely an example, and does not limit the present invention. Therefore, the present invention can naturally be improved and modified in various ways without departing from the gist thereof. For example, in the processing from the left half state to the right half state in FIG. 3, instead of lowering the roller 12 and the outer peripheral mold 11, the turntable 10 may be raised. Further, the rotation of the roller 12 around the rotation axis L2 may be driven to rotate by an original rotation drive source without depending on the rotation by the material 20. Further, the number of rollers 12 provided in the forging apparatus is not limited to two.

DESCRIPTION OF SYMBOLS 10 Turntable 11 Outer periphery type | mold 12 Roller 20 Material 111 Outer periphery type inner peripheral surface L1 Rotation table rotation axis L2 Roller rotation axis

Claims (1)

An arrangement step of arranging the material inside the inner peripheral surface of the outer peripheral type that is a ring-shaped member;
A rotating body-like article having a molding step of rotating the material disposed inside the outer circumference mold around the axial direction of the outer circumference mold and pressing from both end faces in the axial direction to obtain a rotating body article. In the manufacturing method,
Use a material with higher strength than the material as the outer periphery type,
In the molding process,
Press one end of the material with a rotating mold that rotates with the material,
While pressing the other end surface of the material and the outer peripheral mold on the side surface of the roller member that rotates about the rotation axis in the direction intersecting the direction of the rotation axis of the material,
A method for manufacturing a rotating article, wherein the material is processed by moving the roller member and the rotating mold in directions close to each other.

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