JP2013094797A - Method of manufacturing cylindrical member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively reduce eccentricity between a center axis of a first cylindrical part and a center axis of a second cylindrical part without inviting increase in a manufacturing cost.SOLUTION: A main metal fitting as a cylindrical member has a screw part as a form rolled part extended in the direction of an axis CL1 and formed by outer peripheral surface form rolling. Manufacturing steps of the main metal fitting include a step of forming an intermediate cylindrical member MI2 having a first cylindrical part CY1 and a second cylindrical part CY2, and a form rolling step of forming the screw part on the intermediate cylindrical member MI2. In the form rolling step, after inserting, into the intermediate cylindrical member MI2, a receiving member RC which is inserted into the intermediate cylindrical member MI2 and holds the intermediate cylindrical member MI2 between working surfaces of rolling dies D1 and D2 and the receiving member RC, the form rolling is applied simultaneously to at least the first cylindrical part CY1 and the second cylindrical part CY2.

Description

  The present invention relates to a method for manufacturing a cylindrical member having a rolled portion formed on a peripheral surface by a rolling process.

  2. Description of the Related Art Conventionally, a cylindrical member is known that includes a rolled portion such as a male screw, a spline, a serration, or a knurling (knurling) formed on the outer peripheral surface by a rolling process. Examples of the cylindrical member include a metal shell for a spark plug, a pipe joint (nipple) for piping, a worm used for a worm gear, and the like.

  Such a cylindrical member can be manufactured as follows, for example. That is, by performing extrusion molding processing, cutting processing, or the like, a hole (for example, a through hole) is formed in a columnar intermediate member, and an intermediate cylindrical member having a cylindrical portion is obtained. And a cylindrical member can be obtained by giving a rolling process to the outer peripheral surface of an intermediate cylindrical member, and forming a rolling process part.

  By the way, in a cylindrical member such as a metal shell for a spark plug, the inner diameter of one end is different from the inner diameter of the portion different from the one end along the axial direction, or other portions are formed on a part of the inner peripheral surface. A portion having a smaller inner diameter (for example, an annular protrusion) may be provided. As a method for forming such a cylindrical member, for example, a method has been proposed in which extrusion or the like is performed from both one end side and the other end side of the intermediate member, and finally both hole portions are communicated (for example, , See Patent Document 1). In addition, after forming a through hole in the intermediate member by extrusion molding or the like, a method of performing a separate cutting process or the like only on a predetermined portion of the through hole is also conceivable.

Japanese Patent No. 4210611

  However, as in the above method, due to the use of different jigs and manufacturing equipment corresponding to each part having different inner diameters, the inclination of the jig at the time of extrusion, etc., one end of the intermediate cylindrical member Eccentricity between the central axis of the positioned cylindrical part (first cylindrical part) and the central axis of the cylindrical part (second cylindrical part) at a position different from the first cylindrical part along the axial direction ( There is a risk of misalignment or inclination). On the other hand, in order to reduce the eccentricity between the first cylindrical portion and the second cylindrical portion, it is conceivable to separately process the cylindrical member. It will increase the cost.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an effect of eccentricity between the central axis of the first cylindrical portion and the central axis of the second cylindrical portion without causing an increase in manufacturing cost. It is providing the manufacturing method of the cylindrical member which can be made small automatically.

  Hereinafter, each configuration suitable for solving the above-described object will be described in terms of items. In addition, the effect specific to the corresponding structure is added as needed.

Configuration 1. The manufacturing method of the cylindrical member of the present configuration is a manufacturing method of a cylindrical member having a cylindrical shape and having a rolling processed portion formed by a rolling process on its outer peripheral surface,
An intermediate cylindrical member forming step of forming an intermediate cylindrical member in which a cylindrical portion is formed on the intermediate member to be the cylindrical member;
A rolling process for forming the rolled portion by rolling the intermediate cylindrical member using a rolling die;
The intermediate cylindrical member forming step includes
A first cylindrical part forming step of forming a cylindrical first cylindrical part at an end of the intermediate member;
Including a second cylindrical part forming step of forming a cylindrical second cylindrical part in at least a part of the portion different from the first cylindrical part,
In the rolling process,
A receiving member that is inserted into the intermediate cylindrical member and sandwiches the intermediate cylindrical member with the processing surface of the rolling die is inserted into the intermediate cylindrical member, and at least the first cylindrical portion and the first cylindrical portion are inserted. Eccentricity along the radial direction of the central axis of the first cylindrical part and the central axis of the second cylindrical part after the rolling process is performed by simultaneously rolling the two cylindrical parts. Is smaller than the eccentricity along the radial direction between the central axis of the first cylindrical part and the central axis of the second cylindrical part before the rolling process.

  According to the said structure 1, after inserting a receiving member with respect to the intermediate | middle cylindrical member which has a 1st cylindrical part and a 2nd cylindrical part, a rolling process is given with respect to at least both cylindrical parts. . For this reason, when the outer peripheral surface of the intermediate cylindrical member is pressed by the rolling die during the rolling process, a particularly thick portion of the intermediate cylindrical member is sandwiched between the receiving member and the rolling die. It will be crushed and deformed. Thereby, while being able to correct the inclination of the internal peripheral surface of a 1st cylindrical part or a 2nd cylindrical part, the central axis of a 1st cylindrical part (the internal peripheral surface) and a 2nd cylindrical part (of The center axis of the inner peripheral surface) can be corrected so as to coincide with the center axis of the receiving member. As a result, the eccentricity along the radial direction between the central axis of the first cylindrical portion and the central axis of the second cylindrical portion can be effectively reduced as compared with that before the rolling process.

  Also, in order to reduce the eccentricity between the central axis of the first cylindrical part and the central axis of the second cylindrical part, the rolling process when forming the rolled part is used without any additional processing. Therefore, it is possible to suppress an increase in manufacturing cost.

Configuration 2. The manufacturing method of the cylindrical member of this configuration is the above-described configuration 1, wherein the receiving member has a rod shape,
A first component having a shape along the inner peripheral surface of the first tubular portion;
And a second component having a shape along the inner peripheral surface of the second cylindrical portion.

  According to the configuration 2, the receiving member includes the first configuration portion having a shape along the inner peripheral surface of the first cylindrical portion and the second configuration portion having a shape along the inner peripheral surface of the second cylindrical portion. Are provided. Therefore, both the first cylindrical portion and the second cylindrical portion can be corrected more reliably during the rolling process. As a result, the eccentricity between the central axis of the first cylindrical portion and the central axis of the second cylindrical portion can be further reduced.

  Configuration 3. The manufacturing method of the cylindrical member of this configuration is characterized in that, in the above configuration 1 or 2, the receiving member is configured such that a plurality of cylindrical portions are connected in series and the cylindrical portions are separable. To do.

  According to the configuration 3, even if the inner diameter of the first cylindrical portion and the inner diameter of the second cylindrical portion are different, the difference in diameter between the inner diameter of the intermediate cylindrical member and the outer diameter of the receiving member is reduced. It can be adjusted individually in both cylindrical parts. Accordingly, it is possible to more reliably apply a pressing force from the receiving member to both the first cylindrical portion and the second cylindrical portion during the rolling process, and both the first cylindrical portion and the second cylindrical portion. Can be corrected more reliably. As a result, the eccentricity between the central axis of the first cylindrical portion and the central axis of the second cylindrical portion can be further reduced.

  In addition, since each of the cylindrical portions is configured to be separable, there is a portion having an inner diameter smaller than the inner diameter between the first cylindrical portion and the second cylindrical portion as in Configuration 4 described below. Even if it forms, the receiving member (columnar part) of the outer diameter corresponding to each inner diameter of both cylindrical parts can be arrange | positioned to each inner periphery of both cylindrical parts.

  Configuration 4. The manufacturing method of the cylindrical member of this structure is either the said structure 1 thru | or 3 WHEREIN: The said intermediate | middle cylindrical member is said 1st cylinder between said 1st cylindrical part and said 2nd cylindrical part. It has a site | part provided with an internal diameter smaller than the internal diameter of a shape part and said 2nd cylindrical part, It is characterized by the above-mentioned.

  When a portion having an inner diameter smaller than the inner diameter is provided between the first cylindrical portion and the second cylindrical portion, both the cylindrical portions can be formed from one end side of the intermediate member. Since it is difficult, forming the first cylindrical part from one end side and forming the second cylindrical part from the other end side can be performed. However, in this case, the eccentricity of both cylindrical portions tends to be relatively large.

  In this regard, according to the configuration 3, the intermediate cylindrical member has a portion having an inner diameter smaller than the inner diameter of both cylindrical portions between the first cylindrical portion and the second cylindrical portion. Although there is a concern that the eccentricity of the cylindrical portions will be larger, the eccentricity of both cylindrical portions can be sufficiently reduced by adopting the above configuration 1 or the like. In other words, when the intermediate cylindrical member has a portion having an inner diameter smaller than the inner diameter of both cylindrical portions between the first cylindrical portion and the second cylindrical portion, Especially significant.

  In addition, when performing a rolling process to the intermediate | middle cylindrical member of the said structure 4, the receiving member of the said structure 3 is used suitably.

  Configuration 5. The manufacturing method of the cylindrical member of this configuration is characterized in that, in any one of the above configurations 1 to 4, the intermediate cylindrical member has a length along its own axial direction larger than its own outer diameter. .

  If an inclination of the jig or the like occurs in the intermediate cylindrical member forming step, eccentricity occurs between the first cylindrical portion and the second cylindrical portion. However, as in the configuration 5, the intermediate cylindrical member is If the length along the axis is larger than the outer diameter of the axis, the influence of the inclination of the jig is increased, so the eccentricity between the first cylindrical portion and the second cylindrical portion Tends to be larger.

  In this regard, by adopting the above-described configuration 1 or the like, it is possible to more reliably obtain a cylindrical member having a small eccentricity in both cylindrical portions. In other words, in the above-described configuration 1 and the like, the intermediate cylindrical member (cylindrical member) has a longer length along its axis than its own outer diameter, and the eccentricity of both cylindrical portions is increased. This is particularly significant when easy.

  Configuration 6. The manufacturing method of the cylindrical member of this configuration is characterized in that, in any one of the above configurations 1 to 5, the receiving member is freely rotatable around its central axis as a rotation axis in the rolling step. To do.

  According to the configuration 6, the receiving member is freely rotatable with its own central axis as the rotation axis, and is rotatable with the intermediate cylindrical member during the rolling process. Therefore, the frictional force generated between the intermediate cylindrical member and the receiving member can be reduced as much as possible during the rolling process, and as a result, the intermediate cylindrical member can be deformed by being sandwiched between the rolling die and the receiving member. It can be promoted more. As a result, the eccentricity along the radial direction between the central axis of the first cylindrical portion and the central axis of the second cylindrical portion can be extremely effectively reduced.

It is a partially broken front view which shows the structure of a metal shell. It is a perspective view which shows the structure of an intermediate member. It is sectional drawing which shows one process of an intermediate | middle cylindrical member formation process. It is sectional drawing which shows one process of an intermediate | middle cylindrical member formation process. It is sectional drawing which shows one process of an intermediate | middle cylindrical member formation process. It is sectional drawing which shows one process of an intermediate | middle cylindrical member formation process. It is a partially broken front view which shows the structure of a 4th workpiece | work. It is a partially broken front view which shows the structure of an intermediate | middle cylindrical member. It is sectional drawing which shows the receiving member inserted in the intermediate | middle cylindrical member. It is an enlarged front view which shows the conveyance aspect of the intermediate | middle cylindrical member to a rolling die. It is sectional drawing which shows one process of a rolling process. (A) is a partial expanded sectional view for demonstrating the diameter difference of a 1st cylindrical part and a 1st structure part, (b) is a diameter difference of a 2nd cylinder part and a 2nd structure part. It is a partial expanded sectional view for demonstrating. It is a partially broken front view which shows the structure of the valve | bulb in 2nd Embodiment. It is a perspective view which shows the structure of the intermediate member in 2nd Embodiment. It is a partially broken front view which shows the structure of the workpiece | work in 2nd Embodiment. It is a partially broken front view which shows the structure of the intermediate | middle cylindrical member in 2nd Embodiment. It is sectional drawing which shows the receiving member inserted in the intermediate | middle cylindrical member. It is sectional drawing which shows one process of a rolling process. (A) is a partial expanded sectional view for demonstrating the diameter difference of a 1st cylindrical part and a 1st structure part, (b) is a diameter difference of a 2nd cylinder part and a 2nd structure part. It is a partial expanded sectional view for demonstrating. (A)-(d) is a front view which shows the structure of the cylindrical member in another embodiment. It is a top view which shows the structure of the rolling die in another embodiment.

Hereinafter, embodiments will be described with reference to the drawings.
[First Embodiment]
FIG. 1 is a partially cutaway front view showing a spark plug metal shell (hereinafter referred to as “metal shell”) 1 as a tubular member. In FIG. 1, the direction of the axis CL1 of the metal shell 1 is the vertical direction in the drawing, the lower side is the front end side of the metal shell 1, and the upper side is the rear end side.

  The metal shell 1 is formed of a metal such as low carbon steel (for example, the carbon component is 0.5% by mass or less), and includes a through hole 2 extending in the direction of the axis CL1. Further, a threaded portion 3 is formed on the outer peripheral surface of the metal shell 1 as a rolling processed portion for mounting in a mounting hole of a combustion device (for example, an internal combustion engine, a fuel cell reformer, etc.). Further, a seat portion 4 that is directly or indirectly pressed against the combustion device is formed on the outer peripheral surface on the rear end side of the screw portion 3, and on the rear end side of the metal shell 1 on the combustion device. A tool engaging portion 5 having a hexagonal cross section is provided for engaging a tool such as a wrench when mounting.

  Further, on the inner peripheral surface of the metal shell 1, an annular ridge portion 6 that protrudes radially inward is provided. The protrusion 6 is a portion where a cylindrical insulator is locked on the inner periphery of the metal shell 1. Generally, the metal shell 1 has an insulator inserted on its inner periphery, and the opening on the rear end side of the metal shell 1 is radially inward with the stepped portion of the insulator locked to the ridge 6. It is fixed with an insulator by caulking.

  Next, a method for manufacturing the metal shell 1 configured as described above will be described.

  First, as shown in FIG. 2, a cylindrical intermediate member MI1 made of an iron-based material such as S17C or S25C, a stainless steel material, or the like is prepared. Then, in the intermediate cylindrical member forming step, the intermediate member MI1 is subjected to extrusion processing in a stepwise manner using a plurality of molds.

  More specifically, first, the intermediate member MI1 is extruded by cold using the first mold M1 shown in FIG. That is, the first mold M1 has a cavity C1 that extends in the direction of the axis CL1 and that has a rear end side having a large diameter and a front end side having a small diameter. Then, the intermediate member MI1 is inserted into the cavity C1, the cylindrical sleeve S1 is inserted into the distal end side of the cavity C1, and the distal end portion is inserted into the sleeve S1 at the rear end side with respect to the cavity C1 side surface of the sleeve S1. A protruding pin PI1 is disposed. Then, a punch PU1 having substantially the same outer diameter as the large-diameter portion of the cavity C1 is inserted from the rear side of the cavity C1, and the intermediate member MI1 is extruded toward the front end side in the axis CL1 direction. Thereby, while the front end side is formed in a small diameter, the 1st workpiece | work W1 which has the hole HA1 in a front-end | tip part is obtained.

  Next, the first workpiece W1 is extruded by cold using the second mold M2 shown in FIG. That is, the second mold M2 has a cavity C2 having a rear end side having a large diameter and a front end side having a small diameter. Then, the first workpiece W1 is inserted into the cavity C2 from the rear side, and is inserted into the cylindrical sleeve S2 and the sleeve S2 at the distal end side of the cavity C2, and the rear end side of the surface of the sleeve S2 on the cavity C2 side. A pin PI2 having a tip protruding from the pin is disposed. Then, a punch PU2 having an outer diameter smaller than the inner diameter of the large diameter portion of the cavity C2 is inserted from the rear side of the cavity C2. Thereby, the 1st work W1 is extrusion-molded and the 2nd work W2 which has hole part HA2 in the front end side and has hole part HB2 in the back end side is obtained.

  Next, the second workpiece W2 is extruded by cold using the third mold M3 shown in FIG. That is, the third mold M3 has a cavity C3 having a rear end formed with a large diameter and a front end formed with a small diameter. And while inserting the 2nd workpiece | work W2 from the back side with respect to the cavity C3, the cylindrical sleeve S3 and the pin PI3 which the front-end | tip part protrudes in the back end side rather than the sleeve S3 are provided in the front end side of the cavity C3. Deploy. And punch PU3 which has an outer diameter smaller than the internal diameter of the large diameter part of cavity C3, and has a level | step difference in outer periphery is inserted from the back side of cavity C3. As a result, the second workpiece W2 is extruded, and a third workpiece W3 having a hole HA3 on the front end side and a hole HB3 on the rear end side is obtained.

  Next, the third workpiece W3 is extruded by using the fourth mold M4 shown in FIG. That is, the fourth mold M4 has a cavity C4 in which a cylindrical front end mold M41 and a cylindrical rear end mold M42 are coaxially integrated and extend in the direction of the axis CL1. Yes. Here, the inner peripheral portion of the rear end side mold M42 is formed such that the front end side has a large diameter, while the rear end side has a small diameter. The inner peripheral surface of the large diameter portion is formed in a cylindrical shape corresponding to the shape of the seat portion 4. On the other hand, at least the tip side of the inner peripheral surface of the small diameter portion has a shape corresponding to the tool engaging portion 5. Returning to the description of the manufacturing method, the third workpiece W3 is inserted from the rear side into the cavity C4 described above, and the sleeve S4 is provided at the front end side of the cavity C4, and the pin PI4 whose front end portion projects toward the rear end side from the sleeve S4. And place. Then, a punch PU4 having a step on the outer periphery is inserted from the rear side of the cavity C4, and the outer peripheral surface of the third workpiece W3 is brought into pressure contact with the inner peripheral surface of the fourth mold M4. As a result, as shown in FIG. 7, a cylindrical fourth workpiece W4 is obtained which includes the polygonal column part MG having the same cross-sectional shape as the tool engaging part 5 and is communicated with both hole parts HA3 and HB3. It is done. An annular projecting portion P4 (a portion that becomes the projecting ridge portion 6) centering on the axis line CL1 bulges radially inward on the inner peripheral surface of the fourth workpiece W4.

  Thereafter, by cutting the front end side of the polygonal column part MG and the inner peripheral surface on the front end side from the projecting part P4, as shown in FIG. 8, as shown in FIG. 8, the seat part 4, the tool engaging part 5, the ridge part An intermediate cylindrical member MI2 having a cylindrical shape 6 (that is, including a cylindrical portion CY) is obtained.

  Note that the intermediate cylindrical member MI2 has a length along the axis CL1 that is larger than its outer diameter. Further, the intermediate cylindrical member MI2 extends from the front end of the ridge portion 6 to the front end side in the axis CL1 direction, and extends from the rear end of the ridge portion 6 to the rear end side in the axis CL1 direction. A cylindrical second cylindrical portion CY2 is provided. As for the 1st cylindrical part CY1 and the 2nd cylindrical part CY2, each internal diameter is made larger than the internal diameter of the protrusion part 6, and as a result, between 1st cylindrical part CY1 and 2nd cylindrical part CY2 A portion having an inner diameter smaller than the inner diameter of the both (that is, the protrusion 6) is formed between them. Further, the thickness along the radial direction of the first cylindrical portion CY1 and the thickness along the radial direction of the second cylindrical portion CY2 are each relatively small (for example, 5 mm or less). .

  In addition, the inner peripheral surface of the first cylindrical portion CY1 is formed by cutting after extrusion molding, and the inner peripheral surface of the second cylindrical portion CY2 is formed by extrusion molding. Therefore, the central axis of the inner peripheral surface of the first cylindrical portion CY1 and the central axis of the inner peripheral surface of the second cylindrical portion CY2 are easily formed in a state of being eccentric along the radial direction. The above-described extrusion molding and cutting process corresponds to a “first cylindrical part forming process”, and the extrusion molding process corresponds to a “second cylindrical part forming process”.

  In the present embodiment, a cylindrical portion extending from the tip of the ridge 6 toward the tip of the axis CL1 is defined as a first cylindrical portion CY1, and extends from the rear end of the ridge 6 to the rear end of the axis CL1. Although the cylindrical part is the second cylindrical part CY2, the first cylindrical part may be a cylindrical part located at the end of the intermediate cylindrical member MI2, and the second cylindrical part is the first cylindrical part CY2. What is necessary is just a cylindrical part different from a cylindrical part. Therefore, for example, the most distal portion of the intermediate cylindrical member MI2 can be referred to as a first cylindrical portion, and the portion from the rear end of the first cylindrical portion to the protruding portion 6 can also be referred to as a second cylindrical portion. That is, the first cylindrical portion is a cylindrical portion located at the end of the intermediate cylindrical member MI2, but the range along the axial direction is not particularly limited, and the second cylindrical portion is What is necessary is just a cylindrical site | part other than a 1st cylindrical part among cylindrical members MI2.

  Returning to the description of the manufacturing method, in the rolling step, the threaded portion 3 is formed on the outer peripheral surface from the first cylindrical portion CY1 to the second cylindrical portion CY2 in the obtained intermediate cylindrical member MI2. In addition, you may resistance-weld a rod-shaped ground electrode to the front-end | tip part of intermediate | middle cylindrical member MI2 before a rolling process.

  In the rolling process, first, as shown in FIG. 9, a predetermined metal material having a hardness higher than that of the intermediate cylindrical member MI2 [for example, hardened steel (carbon steel) or tool] A rod-shaped receiving member RC made of steel or the like is inserted. In the receiving member RC, the first component part RC1, the intermediate component part RC3, and the second component part RC2 having different outer diameters are connected in series in this order so that the respective central axes coincide with each other. The components RC1, RC2, and RC3 can be separated from each other.

  The first component RC1 has a solid columnar shape, and its outer peripheral surface is shaped along the inner peripheral surface of the first cylindrical portion CY1, and includes a protrusion RP1 at its end. The second component RC2 has a solid cylindrical shape, and its outer peripheral surface is shaped along the inner peripheral surface of the second cylindrical portion CY2, and includes a protrusion RP2 at its end. Yes. The intermediate component RC3 has a cylindrical shape, and the protrusions RP1 and RP2 of the first and second components RC1 and RC2 can be fitted.

  When the receiving member RC is inserted into the intermediate cylindrical member MI2, the first component RC1 is inserted from the distal end side of the intermediate cylindrical member MI2, while the second configuration is inserted from the rear end side of the intermediate cylindrical member MI2. The portion RC2 is inserted, and before the insertion of at least one of the two components RC1 and RC2, the intermediate component RC3 is disposed on the inner periphery of the ridge 6, and each component RC1, inside the intermediate cylindrical member MI2 RC2 and RC3 are connected. For example, the intermediate component RC3 is separated from the second component RC2, and the first component RC1 to which the intermediate component RC3 is connected is inserted from the distal end side of the intermediate cylindrical member MI2, while the intermediate cylindrical member MI2 By inserting the second component RC2 from the rear end side and connecting the second component RC2 and the intermediate component RC3 inside the intermediate cylindrical member MI2, the receiving member RC is attached to the intermediate cylindrical member MI2. Can be inserted. In the present embodiment, in the cross section orthogonal to the axis CL1, the difference in diameter between the inner diameter of the intermediate cylindrical member MI2 and the outer diameter of the receiving member RC is set to 0.002 mm or more, with respect to the intermediate cylindrical member MI2. Thus, the receiving member RC can be easily inserted.

  As shown in FIG. 10, the intermediate cylindrical member MI2 into which the receiving member RC is inserted has a plurality of parts by using a rotary conveyance device CA having a plurality of recesses CO intermittently along the circumferential direction on the outer peripheral surface. (In this embodiment, a pair of) rolling dies D1 and D2 are disposed between the processed surfaces. Specifically, with the intermediate cylindrical member MI2 placed in the concave portion CO, the intermediate transport member CA2 is rotated about its own central axis as the rotation axis, so that the intermediate cylindrical member MI2 is rolled into the dies D1, D2. Arranged between.

  When the intermediate cylindrical member MI2 is disposed between the rolling dies D1 and D2, as shown in FIG. 11, the intermediate cylindrical member MI2 is subjected to a rolling process by the rotation of the rolling dies D1 and D2. . At the time of rolling, the receiving member RC is not supported and is in a freely rotatable state with its own central axis as the rotation axis. Moreover, it is comprised so that the clearance gap between the receiving member RC and both cylindrical part CY1, CY2 may become small enough. In the present embodiment, as shown in FIG. 12A, in the cross section along the radial direction of the first cylindrical portion CY1 of the intermediate cylindrical member MI2 into which the receiving member RC is inserted, the intermediate cylindrical member MI2 (first The diameter difference R1 between the inner diameter of the one-cylindrical part CY1) and the outer diameter of the receiving member RC (first constituent part RC1) is set to 0.8 mm or less. Further, as shown in FIG. 12B, in the cross section along the radial direction of the second cylindrical portion CY2 of the intermediate cylindrical member MI2 into which the receiving member RC is inserted, the intermediate cylindrical member MI2 (second cylindrical shape). The difference R2 between the inner diameter of the portion CY2) and the outer diameter of the receiving member RC (second component RC2) is 0.8 mm or less.

  In addition, in the rolling process, at least the first cylindrical part CY1 and the second cylindrical part CY2 are processed simultaneously. As a result, the threaded portion 3 is formed on the outer peripheral surfaces of the first cylindrical portion CY1 and the second cylindrical portion CY2, and the metal shell 1 is obtained.

  As described in detail above, according to the present embodiment, after the receiving member RC is inserted into the intermediate cylindrical member MI2, at least the first cylindrical portion CY1 and the second cylindrical portion CY2 are rolled. Processing has been applied. For this reason, when the outer peripheral surface of the intermediate cylindrical member MI2 is pressed by the rolling dies D1 and D2 during the rolling process, a particularly thick portion of the intermediate cylindrical member MI2 is rolled with the receiving member RC. It will be crushed and deformed by being sandwiched between the dies D1 and D2. Accordingly, the inclination of the inner peripheral surface of the first cylindrical portion CY1 and the second cylindrical portion CY2 can be corrected, and the central axis of the inner peripheral surface of the first cylindrical portion CY1 and the second cylindrical portion CY2 are corrected. The center axis of the inner peripheral surface can be corrected so as to coincide with the center axis of the receiving member RC. As a result, the eccentricity along the radial direction between the central axis of the first cylindrical part CY1 and the central axis of the second cylindrical part CY2 can be effectively reduced as compared with that before the rolling process.

  Further, in reducing the eccentricity between the central axis of the first cylindrical part CY1 and the central axis of the second cylindrical part CY2, a rolling process when forming the screw part 3 is performed without performing a separate process. Since it is used, it is possible to suppress an increase in manufacturing cost.

  Furthermore, in each cross section of the first cylindrical portion CY1 and the second cylindrical portion CY2, the diameter difference R1, R2 between the inner diameter of the intermediate cylindrical member MI2 and the outer diameter of the receiving member RC is 0.8 mm or less. Yes. Therefore, during the rolling process, the intermediate cylindrical member MI2 is more reliably sandwiched between the rolling dies D1, D2 and the receiving member RC, and the intermediate cylindrical member MI2 can be more reliably deformed. As a result, the eccentricity of both cylindrical portions CY1 and CY2 can be further reliably reduced.

In addition, the receiving member RC can be freely rotated about its own central axis as a rotation axis, and can be rotated together with the intermediate cylindrical member MI2 at the time of rolling. Therefore, the frictional force generated between the intermediate cylindrical member MI2 and the receiving member RC can be reduced as much as possible during the rolling process, and as a result, the intermediate force between the rolling dies D1 and D2 and the receiving member RC The deformation of the cylindrical member MI2 can be further promoted. As a result, the eccentricity of both cylindrical portions CY1 and CY2 can be further reliably reduced.
[Second Embodiment]
Next, a second embodiment will be described with reference to the drawings. In the first embodiment, the configuration of the metal shell 1 and the manufacturing method thereof are described as a cylindrical member. However, in the second embodiment, a bicycle valve bracket (hereinafter referred to as “valve”) as a cylindrical member. The structure of 21 and its manufacturing method will be described.

  As shown in FIG. 13, the valve 21 is formed of a metal such as carbon steel and includes a through hole 22 that extends along the direction of the axis CL <b> 2. Further, a threaded portion 23 is formed on the outer peripheral surface of the valve 21 as a rolling processed portion for attaching a top nut (not shown). Further, on the outer peripheral surface on the rear end side (lower side in FIG. 13) of the screw portion 23 in the axis CL2 direction, knurled portions 24 and 25 for fixing to a rubber seat of a bicycle tire (not shown) and both knurled portions 24 and 25. An annular notch 26 provided therebetween is formed.

  A small-diameter portion 27 having a relatively small inner diameter is provided at the tip end side (upper side in FIG. 13) in the axis CL2 direction of the inner periphery of the valve 21. The small-diameter portion 27 is a portion to which insect rubber (not shown) or the like inserted through the through hole 22 comes into close contact.

  Next, a method for manufacturing the valve 21 configured as described above will be described.

  First, as shown in FIG. 14, a cylindrical intermediate member MI21 made of an iron-based material such as S45C or a stainless material is prepared.

  Then, in the intermediate cylindrical member forming step, a cylindrical workpiece W21 is obtained as shown in FIG. 15 by subjecting the intermediate member MI21 to extrusion molding in stages using a plurality of molds. In the second embodiment, the extrusion molding process corresponds to a “first cylindrical part forming process” and a “second cylindrical part forming process”.

  Furthermore, a knurled groove is formed on the rear end side outer peripheral surface by rolling the rear end side outer peripheral surface of the obtained workpiece W21. Next, by cutting the outer peripheral surface of the rear end side where the knurled grooves are formed, both the knurled portions 24 and 25 and the cutout portions 26 are formed as shown in FIG. An intermediate cylindrical member MI22 having a cylindrical shape (that is, including a cylindrical portion CY20) is obtained.

  The intermediate cylindrical member MI22 has a length that is greater along its axis CL2 than its outer diameter. Further, the intermediate cylindrical member MI22 is located on the distal end side of the cylindrical first cylindrical portion CY21 having a relatively small inner diameter, and is positioned on the rear end side of the first cylindrical portion CY21. A relatively large cylindrical second cylindrical portion CY22 is provided. The thickness along the radial direction of the first cylindrical portion CY21 and the thickness along the radial direction of the second cylindrical portion CY22 are each relatively small (for example, 3 mm or less). .

  Returning to the description of the manufacturing method, in the rolling step, on the outer peripheral surface of the intermediate cylindrical member MI22 located on the tip side of the knurled portion 24 from the first cylindrical portion CY21 to the second cylindrical portion CY22. The screw part 23 is formed.

  In the rolling step, first, as shown in FIG. 17, a predetermined metal material [for example, hardened steel (for example, hardened steel) having a higher hardness than the metal material constituting the intermediate cylindrical member MI22. A rod-shaped receiving member RC20 made of carbon steel) or tool steel is inserted. The receiving member RC20 is arranged in series in this order such that the first constituent part RC21, the second constituent part RC22, and the end face receiving constituent part RC23 having different outer diameters coincide with each other. It is configured. When inserting the receiving member RC20 into the intermediate cylindrical member MI22, the receiving member RC20 is inserted from the rear end side (second cylindrical portion CY22 side) toward the distal end side with respect to the intermediate cylindrical member MI22. Is done.

  The difference between the inner diameter of the intermediate cylindrical member MI22 and the outer diameter of the receiving member RC20 is 0.002 mm or more, and the receiving member RC20 can be easily inserted into the intermediate cylindrical member MI22. . In the second embodiment, the first component RC21, the second component RC22, and the end face receiving component RC23 are integrally formed. However, the components RC21, RC22, and RC23 can be separated from each other. It is good.

  In addition, the first component RC21 has a solid cylindrical shape, and its outer peripheral surface is shaped along the inner peripheral surface of the first cylindrical portion CY21. The second component RC22 is solid While forming a column shape, the outer peripheral surface of itself is made into the shape along the inner peripheral surface of the 2nd cylindrical part CY22. Further, the end surface receiving component RC23 has an outer diameter larger than that of the intermediate cylindrical member MI22, and can contact the rear end surface of the intermediate cylindrical member MI22.

  After inserting the receiving member RC20 into the intermediate cylindrical member M22, as shown in FIG. 18, the intermediate cylindrical member MI22 is arranged between the processing surfaces of the plurality of rolling dies D21 and D22 (note that After the intermediate cylindrical member MI22 is disposed between the rolling dies D21 and D22, the receiving member RC20 may be inserted into the intermediate cylindrical member MI22). And the valve | bulb 21 which has the thread part 23 is obtained by rotating the rolling dice D21 and D22 and performing a rolling process with respect to intermediate | middle cylindrical member MI22.

  At the time of the rolling process, the receiving member RC20 is not supported in the circumferential direction and is in a freely rotatable state with its own central axis as the rotation axis. In the rolling process, at least the first cylindrical part CY21 and the second cylindrical part CY22 are processed simultaneously.

  Further, the gap between the receiving member RC20 and the cylindrical portions CY21 and CY22 is configured to be sufficiently small. In the second embodiment, as shown in FIG. 19A, in the cross section along the radial direction of the first cylindrical portion CY21 of the intermediate cylindrical member MI22 in which the receiving member RC20 is inserted, the intermediate cylindrical member MI22. The diameter difference R21 between the inner diameter of the (first cylindrical part CY21) and the outer diameter of the receiving member RC20 (first component part RC21) is set to 0.3 mm or less. Further, as shown in FIG. 19B, in the cross section along the radial direction of the second cylindrical portion CY22 of the intermediate cylindrical member MI22 in which the receiving member RC20 is inserted, the intermediate cylindrical member MI22 (second cylindrical shape). The diameter difference R22 between the inner diameter of the portion CY22) and the outer diameter of the receiving member RC20 (second component RC22) is 0.2 mm or less.

  As described above, according to the second embodiment, the same operational effects as those of the first embodiment are basically obtained. That is, by performing the rolling process in a state where the receiving member RC20 is inserted into the intermediate cylindrical member MI22, the inclination of the inner peripheral surfaces of both the cylindrical portions CY21, CY22 can be corrected, and the both cylindrical portions CY21, CY22 are corrected. The center axis can be corrected to coincide with the center axis of the receiving member RC20. As a result, the eccentricity along the radial direction between the central axis of the first cylindrical portion CY21 and the central axis of the second cylindrical portion CY22 can be effectively reduced as compared with that before the rolling process.

  In addition, in each cross section of the first cylindrical portion CY21 and the second cylindrical portion CY22, the diameter difference R21 is set to 0.3 mm or less, and the diameter difference R22 is set to 0.2 mm or less. Therefore, during the rolling process, the intermediate cylindrical member MI22 is more reliably sandwiched between the rolling dies D21 and D22 and the receiving member RC20, and the intermediate cylindrical member MI22 can be more reliably deformed. As a result, the eccentricity of both cylindrical portions CY21 and CY22 can be further reliably reduced.

  Next, in order to confirm the effects achieved by the above embodiment, a plurality of samples of the intermediate cylindrical member are produced, and for each sample, the central axis of the tip of the intermediate cylindrical member (corresponding to the first cylindrical portion) The amount of axial deviation along the radial direction of the central axis of a portion (corresponding to the second cylindrical portion) 3 mm rearward from the front end of the intermediate cylindrical member was measured. Next, after inserting a receiving member into each sample, the rolling process is performed to form threaded portions on the outer peripheral surfaces of the first cylindrical part and the second cylindrical part of each sample, and the shaft after the rolling process The amount of deviation was measured. Table 1 shows the amount of axial deviation before rolling and the amount of axial deviation after rolling in each sample. The diameter differences R1 and R2 were set to be 0.8 mm or less, respectively.

  As shown in Table 1, by performing the rolling process after inserting the receiving member, the center axis of the first cylindrical part and the central axis of the second cylindrical part are compared with those before the rolling process. It has been clarified that the amount of axial deviation is reduced and the eccentricity of both cylindrical portions can be further reduced. This is because the outer cylindrical surface of the intermediate cylindrical member is pressed by the rolling die during the rolling process so that a particularly thick portion of the intermediate cylindrical member is sandwiched between the receiving member and the rolling die. This is because the deformation of the inner cylindrical surface of the intermediate cylindrical member is corrected, and the central axis of the intermediate cylindrical member is corrected so that the central axis of the intermediate cylindrical member coincides with the central axis of the receiving member. it is conceivable that.

  In addition, it is not limited to the description content of the said embodiment, For example, you may implement as follows. Of course, other application examples and modification examples not illustrated below are also possible.

  (A) In the above embodiment, the metal shell 1 and the valve 21 are exemplified as the cylindrical member, but the cylindrical member that can be manufactured using the technical idea of the present invention is not limited to these, and the rolling member is not limited to this. If it is a cylindrical member which has the rolling process part formed by a manufacturing process in own outer peripheral surface, it can manufacture using the technical idea of this invention. Therefore, for example, as shown in FIGS. 20A to 20D, a tubular worm 31 having a helical tooth portion 32 on the outer peripheral surface, and a pipe joint in which male screw portions 42 and 43 are formed on the outer peripheral surface. 41. For the production of a cylindrical member 51 (for example, a pen barrel or a motorcycle foot peg) having a knurled 52 formed on the outer peripheral surface, a cylindrical spline shaft 61 having a spline 62 formed on the outer peripheral surface, etc. The technical idea of the present invention may be applied. The method for forming the intermediate member in a cylindrical shape is not particularly limited, and as described above, the intermediate member may be formed in a cylindrical shape by cutting or extruding the columnar member. These members may be wound into a pipe shape to form a cylinder.

  (B) In the above embodiment, the metal shell 1 and the valve 21 as a cylindrical member are provided with through holes, but the cylindrical member has a cylindrical portion at least partially along its own axial direction. For example, the cylindrical member may have a bottomed cylindrical shape.

  (C) In the above embodiment, the metallic shell 1 and the valve 21 as the cylindrical member are configured to have portions having different inner diameters along the axial direction, but the cylindrical member has an inner diameter in the axial direction. It may be constant along.

  (D) In the above embodiment, the receiving member RC (RC20) is configured such that a plurality of components RC1, RC2, RC3 (RC21, RC22, RC23) are arranged in series. However, the present invention is not limited to this, and can be appropriately changed according to the inner peripheral shape of the cylindrical member.

  (E) In the above embodiment, the receiving member RC (RC20) is formed of a metal material, but the constituent material of the receiving member is not particularly limited. Therefore, for example, the receiving member may be made of ceramic. If the receiving member is made of ceramic, the frictional force generated between the outer peripheral surface of the receiving member and the intermediate cylindrical member can be further reduced during the rolling process. As a result, the force along the radial direction applied from the receiving member to the intermediate cylindrical member can be increased, and the eccentricity correction effect can be further improved.

  (F) In the above embodiment, the rolling process is performed by a pair of rolling dies D1, D2 (D21, D22), but the number of rolling dies is not particularly limited. Therefore, for example, as shown in FIG. 21, three rolling dies D3, D4, and D5 arranged so that the respective rotation axes are equally spaced are used to roll the intermediate cylindrical member MI2 (MI22). It is good also as giving a fabrication process.

  (G) In the first embodiment, the diameter differences R1 and R2 between the inner diameter of the receiving member RC and the outer diameters of the cylindrical portions CY1 and CY2 are 0.8 mm or less. As described above, the difference in diameter between the inner diameter of the receiving member and the outer diameters of both cylindrical portions may be appropriately changed according to the manufactured cylindrical member.

  (H) In the first embodiment, the plurality of intermediate cylindrical members MI2 are continuously conveyed between the rolling dies D1 and D2 by the rotary conveying device CA, but between the rolling dies. The arrangement method of the intermediate cylindrical member is not particularly limited. Therefore, after arranging the intermediate cylindrical member before the rolling die, the intermediate cylindrical member is arranged between the rolling dies when one of the intermediate cylindrical member and the rolling die approaches the other. May be. Moreover, the insertion of the receiving member with respect to the intermediate cylindrical member may be performed before the rolling process, and the insertion timing of the receiving member is not particularly limited.

  DESCRIPTION OF SYMBOLS 1 ... Metal fitting (cylindrical member), 3 ... Screw part (rolling process part), 21 ... Valve | bulb (cylindrical member), 23 ... Screw part (rolling process part), CY, CY20 ... Cylindrical part, CY1 , CY21 ... first cylindrical part, CY2, CY22 ... second cylindrical part, D1, D2, D21, D22 ... rolling dies, MI1, MI21 ... intermediate member, MI2, MI22 ... intermediate cylindrical member, RC, RC20 ... receiving member, RC1, RC21 ... first component, RC2, RC22 ... second component.

Claims (6)

A method for producing a cylindrical member having a cylindrical shape and having a rolling processed portion formed by a rolling process on its outer peripheral surface,
An intermediate cylindrical member forming step of forming an intermediate cylindrical member in which a cylindrical portion is formed on the intermediate member to be the cylindrical member;
A rolling process for forming the rolled portion by rolling the intermediate cylindrical member using a rolling die;
The intermediate cylindrical member forming step includes
A first cylindrical part forming step of forming a cylindrical first cylindrical part at an end of the intermediate member;
Including a second cylindrical part forming step of forming a cylindrical second cylindrical part in at least a part of the portion different from the first cylindrical part,
In the rolling process,
A receiving member that is inserted into the intermediate cylindrical member and sandwiches the intermediate cylindrical member with the processing surface of the rolling die is inserted into the intermediate cylindrical member, and at least the first cylindrical portion and the first cylindrical portion are inserted. Eccentricity along the radial direction of the central axis of the first cylindrical part and the central axis of the second cylindrical part after the rolling process is performed by simultaneously rolling the two cylindrical parts. Is made smaller than the eccentricity along the radial direction between the central axis of the first cylindrical part and the central axis of the second cylindrical part before the rolling process. Method. The receiving member has a rod shape,
A first component having a shape along the inner peripheral surface of the first tubular portion;
It has a 2nd component part of the shape along the internal peripheral surface of said 2nd cylindrical part, The manufacturing method of the cylindrical member of Claim 1 characterized by the above-mentioned.   The method for manufacturing a cylindrical member according to claim 1, wherein the receiving member is configured such that a plurality of cylindrical portions are connected in series and the cylindrical portions are separable.   The intermediate cylindrical member has a portion having an inner diameter smaller than inner diameters of the first cylindrical portion and the second cylindrical portion between the first cylindrical portion and the second cylindrical portion. The manufacturing method of the cylindrical member of Claim 3 characterized by these.   The said intermediate cylindrical member is the manufacturing method of the cylindrical member of any one of Claims 1 thru | or 4 whose length along the own axial direction is larger than own outer diameter.   The method for manufacturing a cylindrical member according to any one of claims 1 to 5, wherein the receiving member is freely rotatable in the rolling step with its central axis as a rotation axis.

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