JP5490606B2 - Transport rack and metal ring holding method - Google Patents

Description

  The present invention relates to a transport rack for transporting a metal ring used as a belt for a continuously variable transmission (CVT), and a method for holding the metal ring using the same.

  In CVT, a belt composed of a laminated ring in which a plurality of metal rings are laminated bears power transmission. Here, the metal ring generally has a solution treatment, an aging treatment, and a nitriding treatment for a preform formed by cutting a cylindrical drum made of maraging steel into a predetermined width. It is produced by performing a predetermined heat treatment such as.

  When performing such a heat treatment, it is general that a plurality of metal rings are simultaneously held in a transfer rack and transferred into a heat treatment furnace, and the transfer rack is heated in this state. As this type of transport rack, for example, the one shown in Patent Document 1 is known.

  This transport rack has a plurality of holding shafts erected on a base, and each of the holding shafts is attached with a plurality of ring seats forming an abacus piece shape. In such a configuration, the metal ring is interposed between adjacent ring seats as shown in FIG.

  On the other hand, Patent Document 2 describes that a plurality of piece members are provided on each of a plurality of holding shafts, and an intermediate substrate serving as an aluminum substrate for a magnetic disk is sandwiched between adjacent piece members.

  As described above, holding an annular or disk-shaped work by sandwiching it between pieces provided on a plurality of holding shafts is performed in various technical fields.

JP 2007-191788 A JP 10-251741 A

  The shape of the abacus piece can locally approximate to the triangular prism shaped protrusion 1 shown in FIG. Note that reference numeral 2 in FIG. 17 indicates a holding shaft provided on a base (not shown). In FIG. 17, the holding shaft 2 has a substantially rectangular parallelepiped shape, and the protrusions 1 are provided on the side surface on the short side of the holding shaft 2 so as to be separated at a predetermined interval along the axial direction of the holding shaft 2. Yes.

  A state in which the metal ring 3 is held with respect to the protrusion 1 is shown in FIGS. 18A and 18B. 18A is a front view with the viewpoint as the center of the metal ring 3, while FIG. 18B is a side view along the axial direction of the protrusion 1. As shown in FIGS. 18A and 18B, the metal ring 3 is sandwiched between the protrusions 1 and 1 adjacent to each other.

  The top of the protrusion 1 is directed to the center of the metal ring 3, and for this reason, the lower end surface of the metal ring 3 is placed on the upper inclined surface of the lower protrusion 1, while the bottom of the upper protrusion 1 is The upper end surface of the metal ring 3 abuts on the side inclined surface (see FIG. 18B). Both the lower end surface and the upper end surface of the metal ring 3 are in line contact with the inclined surfaces of the protrusions 1 and 1 (see particularly FIG. 18A).

  From this state, when the metal ring 3 is heated together with the transport rack in order to perform the heat treatment, depending on the difference in thermal expansion coefficient between the protrusions 1, 1 and the metal ring 3, The metal ring 3 in line contact is blocked by the inclined surface (see FIG. 18B). For this reason, there is a concern that the thermal expansion of the metal ring 3 is suppressed. When such a situation occurs, it is also conceivable that the metal ring 3 is distorted.

  Even when the thermal expansion is not suppressed, the line contact between the metal ring 3 and the protrusions 1 and 1 remains maintained. That is, the contact portion between the metal ring 3 and the protrusions 1 and 1 has a relatively large area. Thus, from the contact portion between the metal ring 3 having a large area and the protrusions 1 and 1, for example, when the nitriding process is performed, the heat of the metal ring 3 is taken away by the protrusions 1 and 1. For this reason, there is a concern that the metal ring 3 does not sufficiently rise in temperature, and the nitriding treatment does not sufficiently proceed due to this.

  The present invention has been made to solve the above-described problems, and can eliminate the concern that the metal ring may be distorted. Further, the present invention uses a transport rack that suppresses heat from being removed from the metal ring, and uses the same. An object of the present invention is to provide a method for holding a metal ring.

To achieve the above object, the present invention is a transport rack for holding and transporting a plurality of metal rings having elastic restoring force,
The foundation,
A plurality of mounting projections which are provided on the base and extend in parallel with each other and projecting toward the metal ring are provided on the side walls, and the metal is disposed above the mounting projections. A plurality of holding shafts for holding the metal ring by placing the ring;
A damming projection that protrudes from the holding shaft and is interposed between adjacent mounting projections and abuts against the side wall of the metal ring to press the metal ring inward in the diameter direction. And
It is characterized by having.

  In the present invention, the damming projection is pressed and held in the state where the expansion force is generated in the metal ring. Therefore, the mounting projection portion can have an auxiliary role for preventing the metal ring from falling rather than the main role for holding the metal ring. For this reason, the contact area between the metal ring and the mounting projection can be made as small as possible.

  Therefore, when the heat treatment is performed on the metal ring, the heat of the metal ring is suppressed from being taken away by the mounting protrusion. In other words, the amount of heat taken by the mounting protrusion can be minimized. Therefore, it is possible to sufficiently raise the temperature of the metal ring. In addition, the temperature of the metal ring is substantially uniform throughout.

  Further, since the contact area between the metal ring and the mounting projection is small, various gases such as a nitriding gas come into contact with substantially the entire metal ring. This, combined with the fact that the temperature of the metal ring is substantially uniform throughout, allows the heat treatment to be performed substantially evenly over the entire metal ring. That is, for example, nitriding treatment or the like can be performed evenly.

  In addition, since the contact area between the mounting projection and the metal ring is extremely small, the restraining force of the mounting projection on the metal ring is small. Accordingly, when heat treatment is performed on the metal ring, the metal ring can be thermally expanded so as to approach the holding shaft without being blocked by the mounting projection. In other words, since the suppression of the thermal expansion of the metal ring is avoided, the concern that the metal ring is distorted is eliminated.

  In the present invention, it is preferable that the mounting projection is formed as a cylindrical body, and the diameter thereof is set to a size at which the mounting projection is in point contact with the metal ring. In the case of point contact, the contact area between the mounting projection and the metal ring is minimized. Therefore, the above-described effect becomes more remarkable.

  Note that two or more rows of metal rings may be held by one transport rack. In this case, the plurality of holding shafts may be arranged so as to be held in a state in which two or more metal rings are arranged in tandem.

  Moreover, it is preferable to further provide a connection board that is arranged apart from the base and in which the ends of all the holding shafts are connected. This prevents the holding shaft holding the metal ring from being inclined. Accordingly, it is possible to avoid the metal ring from dropping off due to the inclination of the holding shaft.

  Furthermore, the holding shaft is preferably made of nickel or a nickel-based alloy. Of course, a nickel or nickel-based alloy film may be formed on the surface.

  Nickel functions as a barrier against diffusion of constituent elements of the holding shaft into the metal ring during various heat treatments such as nitriding. Therefore, a metal ring having a good appearance (excellent in appearance) can be easily obtained.

  Furthermore, at least a part of the plurality of holding shafts can be displaced in a direction in which the diameter of an inscribed circle formed by the holding shafts increases or decreases. It is preferable to stand upright. In this case, by displacing the holding shaft so that the diameter of the inscribed circle is appropriately changed, it is possible to cope with the diameter of the metal ring to be subjected to various heat treatments such as nitriding treatment. That is, it is possible to hold metal rings of various diameters.

  In this case, when a plurality of holding shafts are arranged so that they can be held in a state where metal rings are arranged in two or more rows, and are provided with the connecting plate arranged apart from the base, they are adjacent to each other. The holding shaft that holds both of the two rows of metal rings is positioned and fixed. On the other hand, the holding shaft that holds only one row of metal rings can be displaced, and the axial dimension of the holding shaft that is positioned and fixed is displaced. It is preferable to set larger than the possible holding shaft.

  The carrier rack may be bent by the heat generated during heat treatment. In particular, when a connecting board is provided, the base and the connecting board tend to bend in a direction approaching each other. When such a situation occurs, there is a concern that the holding shaft is sandwiched between the bent base and the connecting board, and it becomes difficult to displace.

  On the other hand, when said structure is employ | adopted, a base | substrate and a connection board will bend so that it may mutually approach in connection with a holding shaft. Therefore, after the heat treatment is completed, when the base and the connection board are detached from the holding shaft that holds only one row of metal rings, the base and the connection board are elastically separated from the holding shaft that holds only one row of metal rings. To do.

  As a result, the holding shaft that holds only one row of metal rings is released from restraint by the base and the connecting board. Therefore, the holding shaft can be easily displaced.

  In addition, in this case, it is not necessary to release the holding shaft that holds both the two rows of metal rings from the restraint by the base and the connecting board. Accordingly, the working time can be shortened by this amount, so that the time until the next metal ring is held is shortened. As a result, the processing efficiency of the metal ring is improved.

  Of course, all of the plurality of holding shafts may be provided so as to be displaceable. According to this configuration, for example, when two or more metal rings are held in one transport rack, one row holds a small-diameter metal ring, while another row holds a large-diameter metal ring. Is possible. That is, it is possible to hold the metal rings having different diameters at the same time and perform the heat treatment as described above.

In addition, the present invention provides a transport rack comprising a plurality of holding shafts that are erected on a base and extend parallel to each other in order to heat-treat a plurality of metal rings having elastic restoring force. A metal ring holding method for holding a ring,
The metal ring is placed above a plurality of placement projections provided on a side wall of the holding shaft, and the damming projections interposed between the placement projections are adjacent to each other. The metal ring is held by being brought into contact with a side wall of the metal ring.

  By performing such holding, the temperature of the metal ring during the heat treatment becomes substantially uniform throughout the heat treatment for the reasons described above, and various heat treatment gases such as a nitriding gas come into contact with the substantially entire metal ring. Therefore, the heat treatment can be performed evenly. In addition, the concern that the metal ring may be distorted can be eliminated.

  In this holding method, it is preferable that at least a part of the plurality of holding shafts is provided so as to be displaceable in a direction in which the diameter of an inscribed circle formed by the holding shafts increases or decreases.

  In this way, when at least a part of the holding shaft is installed to be displaceable on the base, the holding shaft is displaced so that the diameter of the inscribed circle is appropriately changed, so that the diameter of the metal ring to be heat-treated is obtained. Can respond. That is, by changing the position of the holding shaft, it is possible to hold metal rings having various diameters.

  In this case, a plurality of holding shafts are arranged so that they can be held in a state in which the metal rings are arranged in two or more rows, and when the connecting plate is provided, the holding shafts that hold both adjacent two rows of metal rings. The holding shaft that holds only one row of metal rings is displaceable, and the axial dimension of the holding shaft that is positioned and fixed is compared with the displaceable holding shaft. It is preferable to set a large value. Then, only the holding shaft that can be displaced may be displaced after being released from the restraint on the base.

  As described above, this makes it possible to easily displace the holding shaft. In addition, the processing efficiency of the metal ring can be improved.

  Of course, for the reason described above, all of the plurality of holding shafts may be displaced.

  According to the present invention, the metal ring in the state where the expansion force is generated is pressed and held by the blocking protrusion. That is, the metal ring is mainly held by the blocking protrusion. For this reason, since the mounting protrusion can be an auxiliary role for preventing the metal ring from falling rather than the main role for holding the metal ring, The contact area between the metal ring and the mounting projection can be made as small as possible.

  Therefore, it is avoided that the metal ring is restrained by the mounting protrusion during the heat treatment and can be easily thermally expanded, so that the metal ring is prevented from being distorted.

  In addition, since the contact area between the mounting projection and the metal ring is reduced, heat transfer between the mounting projection and the metal ring is minimized, and various gases contact almost the entire metal ring. To come. In other words, various gases come into contact with the metal ring that has a substantially uniform temperature throughout the entire surface. Accordingly, the heat treatment is performed on the entire metal ring substantially evenly. For this reason, for example, the nitriding treatment can be performed evenly.

  When the holding shaft is erected so as to be displaceable, it is possible to hold metal rings having various diameters by setting the position of the holding shaft. Therefore, it is not necessary to prepare a plurality of transport racks according to the number of metal rings having different diameters. For this reason, the capital investment can be reduced.

1 is an overall schematic perspective view of a transport rack according to a first embodiment. It is a whole schematic perspective view which shows the state which hold | maintained the metal ring in 2 rows to the conveyance rack of FIG. It is a partial longitudinal cross-sectional side view of the conveyance rack of FIG. FIG. 2 is an enlarged vertical sectional view of a main part of the transport rack in FIG. 1. It is a principal part schematic perspective view of the holding shaft which comprises the conveyance rack of FIG. FIG. 6A is a front view of the main part showing the state in which the lower end surface of the metal ring is in point contact with the protrusion shown in FIG. 5 from the center of the metal ring, and FIG. It is a principal part side view along the axial direction of a projection part. FIG. 2 is an upper plan view of the transport rack of FIG. 1. It is a longitudinal cross-sectional front view which shows the state which introduced the conveyance rack in the heat processing furnace. It is a disassembled perspective view at the time of laminating | stacking a conveyance rack. FIG. 10 is an overall schematic perspective view illustrating a state in which the transport racks are stacked from FIG. 9. It is the plane sectional view which looked at the conveyance rack concerning a 2nd embodiment from the base side which constitutes the conveyance rack. FIG. 12 is a longitudinal sectional view in the vicinity of one end portion of the holding shaft when the holding shaft constituting the transport rack of FIG. 11 is positioned at the backward movement end. FIG. 13 is a longitudinal sectional view in the vicinity of one end of the holding shaft when the holding shaft of FIG. 12 is displaced to the forward end. In the transport rack according to the second embodiment, the axial dimension of the holding shaft that holds both the two rows of metal rings is larger than the holding shaft that holds only one row of the two rows of metal rings. It is a front view in the case. FIG. 15 is a front view showing a state in which the restraint of the base and the connecting board with respect to the holding shaft that holds only one row of the two rows of metal rings is released from FIG. 14. It is the plane sectional view which looked at the conveyance rack which concerns on the modification of 2nd Embodiment which enabled displacement of all the holding shafts from the base | substrate side which comprises this conveyance rack. It is a principal part schematic perspective view of the holding shaft which comprises the conveyance rack which concerns on a prior art. 18A is a main part front view showing the state in which the metal ring is sandwiched between the protrusions shown in FIG. 17 from the center of the metal ring, and FIG. 18B is a side view of the main part along the axial direction of the protrusions. It is.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a transport rack according to the present invention will be described in detail with reference to the accompanying drawings by giving preferred embodiments in relation to a metal ring holding method using the same.

  FIG. 1 is an overall schematic perspective view of the transport rack 10 according to the first embodiment, and FIG. 2 is an overall schematic perspective view showing a state in which metal rings R1 and R2 are held on the transport rack 10. This transport rack 10 is for holding and transporting a plurality of metal rings R1 as a first row L1 and a plurality of metal rings R2 as a second row L2, and is erected on the base 12 and the base 12 The ten holding shafts 14a to 14j and the connecting board 16 connected to all of the ten holding shafts 14a to 14j.

  The metal rings R1 and R2 are given separate reference numerals for convenience of explanation, but the configurations of the metal rings R1 and R2 are the same. In the holding shafts 14a to 14j, the holding shafts 14a to 14d and 14f to 14i have the same configuration, and the holding shafts 14e and 14j have the same configuration.

  The base 12 has a shape in which a right-angled isosceles triangle is cut out from the long side to the short side of the flat plate, thereby forming an octagonal shape. The base 12 is formed with large circular openings 18a, 18b and small circular openings 20a, 20b for weight reduction. By forming the large circular openings 18a and 18b and the small circular openings 20a and 20b, the connection board 16 is reduced in weight, which ultimately contributes to the weight reduction of the transport rack 10.

  Further, as shown in FIG. 3, the base 12 has a holding shaft insertion recess 22, a bolt insertion hole 24 penetrating from the lower surface of the base 12 to the holding shaft insertion recess 22, and two connecting pin insertion holes 26. Is formed. The lower ends of the holding shafts 14 a to 14 j are inserted into the holding shaft insertion recesses 22 and connected to the base 12 by bolts 28 inserted into the bolt insertion holes 24. Thereby, the holding shafts 14 a to 14 j are erected on the base 12.

  4 and 5 show a longitudinal sectional view and a schematic perspective view of the main part of the holding shaft 14e, respectively. As can be understood from FIGS. 4 and 5, the holding shaft 14 e is formed as a quadrangular prism body, and has a substantially cylindrical mounting projection 30 and a damming projection 32 on the two short side surfaces. Is a solid body in which a plurality of are formed.

  As described above, the holding shaft 14j has the same configuration as the holding shaft 14e. Further, the remaining holding shafts 14a to 14d and 14f to 14i are configured such that the mounting projection 30 and the blocking projection 32 are formed only on one of the two short side surfaces. It is configured in accordance with the holding shaft 14e.

  The mounting projections 30 of the holding shafts 14a to 14d and 14f to 14i are provided so that the top surfaces are directed to the centers of the metal rings R1 and R2. On the other hand, the mounting projections 30 of the holding shafts 14e and 14j extend so that their top surfaces are oriented in the longitudinal direction of the base 12, and face the metal rings R1 and R2.

  If the diameter of each mounting projection 30 is excessively large, the circumferential length of the mounting projection 30 increases, and for this reason, the mounting projection 30 causes line contact with the metal rings R1 and R2. It becomes like this. In order to avoid this, in the first embodiment, the diameter of each mounting protrusion 30 is set to a dimension that makes point contact with the metal rings R1 and R2.

  The damming projections 32 are also formed as cylindrical bodies, and each damming projection 32 is disposed between the mounting projections 30 and 30 adjacent to each other. Further, the axial direction (height direction dimension) extending toward the metal rings R <b> 1 and R <b> 2 of each damming protrusion 32 is set smaller than that of the mounting protrusion 30.

  As shown by a two-dot chain line in FIG. 4, the metal rings R <b> 1 and R <b> 2 are inserted between the adjacent placement projections 30 and 30, but the placement projections in which the lower end surfaces are located below. It is only placed in a point contact state on 30, and the upper end surface is separated from the placement projection 30 positioned above. That is, the metal rings R1 and R2 do not come into contact with the mounting protrusion 30 positioned above.

  On the other hand, the side walls of the metal rings R1 and R2 are in contact with the top surface of each damming projection 32. The metal rings R1 and R2 press the blocking protrusion 32 toward the holding shafts 14a to 14j with the expansion force. In other words, the metal rings R1 and R2 are slightly contracted inward in the diametrical direction by being pressed from the damming projections 32 of the holding shafts 14a to 14j, and are elastically deformed to return to the original diameter. In the state in which force (expansion force) is acting, it is blocked by the blocking projection 32.

  The holding shafts 14a to 14j having such a shape can be manufactured by forming the mounting protrusion 30 by cutting a solid rectangular column body from the outer wall side, for example. Alternatively, the rectangular column body and the mounting projection 30 are produced as separate members, and, for example, a screw hole is drilled in the side surface of the short side of the square column body, while the mounting projection 30 A screwing round bar having a threaded portion formed on the bottom surface may be provided, and the screwing round bar may be screwed into the screw hole.

  Of course, as shown in FIG. 1, the holding shafts 14 a to 14 j are erected on the base 12 so that the positions of the mounting projections 30 and the damming projections 32 coincide with each other. Accordingly, the lower end surface of the metal ring R1 is placed on each placement projection 30 of the holding shafts 14a to 14e, 14j, and the metal ring R2 is placed on each placement projection 30 of the holding shafts 14e to 14j. Placed. That is, of the holding shafts 14a to 14j, two of the holding shafts 14e and 14j hold both the metal rings R1 and R2 (first row L1 and second row L2).

  Further, the damming projection 32 provided on the holding shafts 14a to 14j abuts against the side walls of the metal rings R1 and R2. The diameter of the imaginary circle connecting the top surfaces of the damming projections 32 is smaller than the diameter of the metal rings R1 and R2, so that the metal rings R1 and R2 are pressed from the damming projections 32 and have a diameter. It is slightly shrunk inward in the direction.

  In the above configuration, a nickel film is formed on the surfaces of the side walls of the holding shafts 14a to 14j by, for example, nickel plating. Instead of forming a nickel film, the holding shafts 14a to 14j may be made of nickel.

  The connecting board 16 is substantially H-shaped. The connecting board 16 having such a shape is significantly lighter than a flat board. That is, by making the connecting board 16 substantially H-shaped, it is possible to further reduce the weight of the connecting board 16 and thus the transport rack 10.

  In addition, a holding shaft insertion recess 34 is formed in the lower surface of the connection board 16 at a position corresponding to the holding shaft insertion recess 22 in the base 12, while the connection pin insertion hole 26 in the base 12 is formed on the upper surface. A connecting pin fixing hole 36 is formed at a position corresponding to the position of. Further, a bolt insertion hole 38 is formed to penetrate from the upper end surface of the coupling board 16 to the holding shaft insertion recess 34. Each upper end portion of the holding shafts 14a to 14j is inserted into the holding shaft insertion recess 34 and is connected to the connecting board 16 by a bolt 40 inserted into the bolt insertion hole 38.

  On the other hand, a threaded portion is formed on the inner wall of the connecting pin fixing hole 36. A connecting pin 42 having a threaded portion on the side wall is screwed into the connecting pin fixing hole 36. As will be described later, when the transport racks 10 are stacked, the connection pins 42 are inserted into the connection pin insertion holes 26 of the base 12 constituting the upper transport rack 10.

  The transport rack 10 according to the first embodiment is basically configured as described above. Next, regarding the function and effect of the metal rings R1 and R2 implemented using the transport rack 10, This will be described in relation to the heat treatment method.

  First, prior to the connection plate 16 being connected to the holding shafts 14a to 14j, the metal rings R1 and R2 are held on the holding shafts 14a to 14j as the first row L1 and the second row L2. Of course, each of the holding shafts 14 a to 14 j is erected in advance on the base 12 via a bolt 28 inserted into the bolt insertion hole 24.

  Here, the metal rings R1 and R2 are produced, for example, by cutting a cylindrical drum made of maraging steel into a predetermined width, and have an elastic restoring force against the pressing force. That is, when released from the pressing force, it returns to its original shape by its elastic action.

  A plurality of metal rings R1 configured as described above are gripped by a gripping device (not shown) from the outer peripheral wall side. At this time, a gripping force (pressing force) is applied to the metal ring R1 through the gripping device, whereby all the metal rings R1 are simultaneously deformed into an elliptical shape, for example. In other words, the metal ring R1 is gripped by the gripping device in a state of being deformed into an elliptical shape or the like. Of course, this deformation takes place within the elastic region of the metal ring R1.

  The plurality of metal rings R1 deformed into an oval shape or the like are transferred between the holding shafts 14a to 14e and 14j. The gripping device stops at a position where each of the metal rings R1 is disposed between the mounting projections 30 adjacent to each other in the height direction of the holding shafts 14a to 14e and 14j.

  Thereafter, all the metal rings R1 are simultaneously released from the gripping force by the gripping device, and accordingly, the metal rings R1 return to the original substantially circular shape by the elastic restoring force. At this time, the lower end surface of each metal ring R <b> 1 is placed on the placement protrusion 30 positioned below the metal ring R <b> 1. At the same time, the side wall of the metal ring R1 comes into contact with the blocking protrusion 32.

  As described above, the diameter of the imaginary circle that connects the top surfaces of the blocking protrusions 32 formed on the holding shafts 14a to 14e and 14j is smaller than the diameter of the metal ring R1. For this reason, the metal ring R1 is pressed from the damming projection 32 and slightly contracted inward in the diameter direction.

  As a result, as shown in FIG. 2, the plurality of metal rings R1 are simultaneously held on the holding shafts 14a to 14e and 14j as the first row L1.

  Next, the gripping device grips a plurality of metal rings R2 at the same time, deforms into an elliptical shape or the like as described above, and transfers the metal ring R2 between the holding shafts 14e to 14j in this state. Thereafter, in the same manner as described above, after the gripping device stops at a position where each of the metal rings R2 is disposed between the mounting projections 30 of the holding shafts 14e to 14j, all the metal rings R2 are held by the grips. Simultaneously released from the gripping force by the device. With this release, all the metal rings R2 return to a substantially perfect circle shape.

  Of course, at this time, as shown in FIG. 6A, the lower end surface of each metal ring R2 is placed on the placing projection 30 positioned below the metal ring R2, and at the same time, as shown in FIG. The side wall of the metal ring R <b> 2 comes into contact with the damming projection 32 and is pressed slightly from the damming projection 32, so that the metal ring R <b> 2 is slightly contracted inward in the diameter direction. Thus, the metal ring R2 is held on the holding shafts 14e to 14j as the second row L2.

  The metal rings R1 and R2 are held in a stepped state so as to avoid mutual interference.

  As described above, in the first embodiment, the diameter of the mounting protrusion 30 is set to a dimension that makes point contact with the metal rings R1 and R2. Therefore, as shown in FIG. 6A, the lower end surface of the metal ring R <b> 1 (R <b> 2) is in point contact with the curved side wall of the mounting projection 30 at a location marked with a symbol x. That is, the metal ring R1 (R2) and the mounting projection 30 are in point contact with each other.

  In the first embodiment, the blocking protrusion 32 presses and holds the metal rings R1 and R2 in the state where the expansion force is generated (see FIG. 6B). Therefore, the mounting protrusion 30 is not the main role for holding the metal rings R1 and R2, but an auxiliary role for preventing the metal rings R1 and R2 from falling vertically downward. Can be. For this reason, the contact area of metal ring R1, R2 and the projection part 30 for mounting can be made as small as possible.

  When the metal rings R <b> 1 and R <b> 2 are held as described above, the upper end portions of the holding shafts 14 a to 14 j are inserted into the holding shaft insertion recesses 34 formed on the lower surface of the coupling board 16. Thereafter, as shown in FIG. 7, the upper ends of the holding shafts 14 a to 14 j are connected to the connection board 16 through the bolts 40 inserted into the bolt insertion holes 38 (FIG. 7 shows the base 12. In order to show the positional relationship between the holding shafts 14a to 14j and the connecting board 16, the metal rings R1 and R2 are not shown). Further, the connecting pin 42 is screwed into the connecting pin fixing hole 36 as necessary.

  Thus, the metal rings R1 and R2 and the transport rack 10 are in the state shown in FIG. By connecting the connecting plate 16 to the holding shafts 14a to 14j, it is possible to prevent the holding shafts 14a to 14j from being inclined and the inclination to prevent the metal rings R1 and R2 from dropping from the holding shafts 14a to 14j. .

  As described above, when the connecting plate 16 is connected after the metal rings R1 and R2 are held by the holding shafts 14a to 14j, it is possible to use a simple gripping device. Although it is necessary to use a gripping device having a slightly complicated structure as compared to this gripping device and to perform control related to the transfer operation slightly strictly, each upper end of the holding shafts 14a to 14j erected on the base 12 After connecting the connecting plate 16 to the part, the metal rings R1 and R2 may be held by the holding shafts 14a to 14j. In this case, the metal rings R1 and R2 may be inserted from between two adjacent ones of the holding shafts 14a to 14j.

  Next, the metal rings R1 and R2 are transferred together with the transfer rack 10 into the heat treatment furnace 80 shown in FIG. 8 under the action of a transfer (not shown). As described above, the base 12 constituting the transport rack 10 has the large circular openings 18a and 18b and the small circular openings 20a and 20b formed therethrough, while the connecting board 16 is substantially H-shaped. . Accordingly, the transport rack 10 is lighter than a transport rack having a flat base and a connecting board.

  Furthermore, since the two central holding shafts 14e and 14i simultaneously hold both the first row L1 of the metal ring R1 and the second row L2 of the metal ring R2, an increase in the number of holding shafts is avoided. . By adopting such a configuration, the holding shafts 14a to 14j and, consequently, the weight of the transport rack 10 is greatly contributed.

  For this reason, the transport rack 10 can be transported easily. Further, it is possible to save power required for transportation.

  The heat treatment furnace 80 is formed to be long along the conveyance direction of the conveyance rack 10, heaters 86 and 88 are installed inside the side walls 82 and 84, and a convection fan 92 is installed on the ceiling wall 90. It is configured. The transport rack 10 supported by the transfer via the mounting jig 94 is carried into the heat treatment furnace 80 together with the mounting jig 94.

  A case where nitriding is performed as the heat treatment will be described as an example. A nitriding gas such as ammonia is supplied into a heat treatment furnace 80 shown in FIG. The nitriding gas is raised to a predetermined temperature at which the metal rings R1 and R2 can be nitrided under the action of the heaters 86 and 88, for example, about 500 ° C.

  As this temperature rises, the metal rings R1 and R2 receive radiant heat and cause thermal expansion so as to approach the holding shafts 14a to 14j.

  Here, as described above, the lower end surfaces of the metal rings R1 and R2 are held in a point contact with the mounting projection 30 (see FIG. 6). Therefore, the restraining force of the mounting projection 30 on the metal rings R1 and R2 is small. For this reason, the metal rings R <b> 1 and R <b> 2 can be thermally expanded without being blocked by the mounting projection 30.

  That is, according to 1st Embodiment, it can avoid that the thermal expansion of metal ring R1, R2 is suppressed. Therefore, the concern that distortion occurs in the metal rings R1 and R2 is eliminated.

  Moreover, since the metal rings R1 and R2 are in point contact with the mounting projection 30, the contact area between them is small. For this reason, the amount of heat taken by the metal rings R1 and R2 from the mounting projection 30 is small. That is, the contact between the metal rings R1 and R2 and the mounting projection 30 is a point contact, and the contact area is reduced, so that heat is transferred from the metal rings R1 and R2 to the mounting projection 30. This can be suppressed.

  Therefore, the temperature of the metal rings R1 and R2 easily rises. In other words, it becomes easy to raise to a temperature at which nitriding proceeds sufficiently.

  The nitriding gas whose temperature has risen rises toward the ceiling wall 90 of the heat treatment furnace 80 (see FIG. 8). Here, in the first embodiment, the convection fan 92 is energized to rotate the stirring blade 96, thereby convection of the nitriding gas in the heat treatment furnace 80. Therefore, the nitriding gas descends along the side wall, and then tries to rise again in the vicinity of the mounting jig 94 and eventually the transport rack 10.

  As described above, the lower end surfaces of the metal rings R1 and R2 are in point contact with the mounting protrusion 30 positioned below the metal rings R1 and R2. That is, the contact area between the metal rings R1 and R2 and the mounting protrusion 30 is extremely small. For this reason, the nitriding gas sufficiently circulates in the vicinity of the contact portion between the metal rings R1 and R2 and the mounting protrusion 30.

  In other words, in the case of the first embodiment, the nitriding gas comes into contact with substantially the entire metal rings R1 and R2. In addition, since heat transfer between the metal rings R1 and R2 and the mounting projection 30 is suppressed to a minimum, the temperatures of the metal rings R1 and R2 become substantially uniform throughout. In other words, the temperature of the contact point between the holding shafts 14a to 14j and the metal rings R1 and R2 is substantially equal to the temperature of other portions of the metal rings R1 and R2.

  For this reason, nitriding proceeds substantially equally throughout the metal rings R1, R2. That is, variation in the nitriding progress is avoided, and therefore variation in the thickness of the nitrided layer and hence the degree of curing is also avoided.

  As described above, according to the first embodiment in which the mounting protrusions 30 provided on the holding shafts 14a to 14j and the metal rings R1 and R2 are in a point contact state, the temperatures of the metal rings R1 and R2 are set over the entire temperature. The nitriding gas can be brought into contact with substantially the entire metal rings R1 and R2. Therefore, the metal rings R1 and R2 can be nitrided substantially uniformly over the entire surface, thereby being cured substantially uniformly.

  Further, since the nickel film is formed on the surface of the side walls of the holding shafts 14a to 14j, the constituent elements of the holding shafts 14a to 14j are prevented from diffusing into the metal rings R1 and R2 during the nitriding process. . That is, the nickel coating functions as a barrier against diffusion of the constituent elements of the holding shafts 14a to 14j into the metal rings R1 and R2. Of course, the same applies to the case where the holding shafts 14a to 14j themselves are made of nickel.

  After the nitriding treatment is performed on the metal rings R1 and R2 in this way, the transport rack 10 is led out from the heat treatment furnace 80. Thereafter, the nut 48 is loosened, the connecting board 16 is removed from the holding shafts 14a to 14j, and the metal rings R1 and R2 are exposed.

  The exposed metal rings R1 and R2 are gripped by the gripping device, removed from the holding shafts 14a to 14j in a state of being deformed into an elliptical shape, and transferred to a predetermined station or storage location. Of course, the metal rings R1 and R2 released from the gripping device return to a substantially perfect circle shape under their own elastic action.

  Thereafter, when holding another new metal ring R1, R2, the transport rack 10 including the holding shafts 14a to 14j produced as described above is repeatedly used.

  Here, FIG. 8 shows a case where the transport rack 10 is carried into the heat treatment furnace 80 without being stacked, but when a heat treatment furnace having a large capacity is used, as shown in FIG. 9 and FIG. The transport racks 10, 10 may be stacked via the pins 42 and carried into the heat treatment furnace in this state.

  Similarly, it goes without saying that the transport racks 10 may be stacked in three or more stages.

  In 1st Embodiment, while inserting the lower end part of each of holding shaft 14a-14j in the recessed part 22 for holding shaft insertion formed in the base | substrate 12, bolt hole 110a formed in the lower end part of holding shaft 14a-14j, The bolt 28 passed through the bolt insertion hole 24 is screwed to 110b, and thereby the holding shafts 14a to 14j are positioned and fixed, and are erected on the base 12 (see FIG. 4). The holding shaft may be erected so as to be displaceable. Hereinafter, this case will be described as a second embodiment. In the following description, components having the same reference numerals as those shown in FIG. 1 to FIG. 10 are the same components. Therefore, the detailed description is abbreviate | omitted.

  FIG. 11 is a cross-sectional plan view of the transport rack 100 according to the second embodiment viewed from the side of the base 102 constituting the transport rack 100. Here, in FIG. 11, in order to clarify the positional relationship between the holding shafts 104 a to 104 j and the long hole-like bolt insertion holes 106 a and 106 b formed through the base 102, the base 102 is indicated by an imaginary line. The hole-like bolt insertion holes 106a and 106b are indicated by solid lines.

  The transport rack 100 includes ten holding shafts 104a to 104j arranged in the same manner as the holding shafts 14a to 14j in the transport rack 10 according to the first embodiment. The six holding shafts 104a to 104e and 104j hold the first row L3 (a plurality of metal rings R3), and the six holding shafts 104e to 104j hold the second row L4 (a plurality of metal rings R4). ).

  The two holding shafts 104e and 104j have the same configuration as each of the holding shafts 14e and 14j in the first embodiment. However, for convenience of explanation, different reference numerals are given in the second embodiment.

  The two holding shafts 104e and 104j that simultaneously hold the first row L1 and the second row L4 are similar to the holding shafts 14e and 14j in the first embodiment connected to the base 12 via the bolts 28. It is connected to the base 102 via a bolt 28. That is, the holding shafts 104e and 104j are positioned and fixed by being connected to the base 102 with the same configuration as that shown in FIG.

  On the other hand, the remaining holding shafts 104a to 104d and 104f to 104i can be displaced in a direction in which the top surface of each mounting projection 30 approaches or separates from the center of the metal rings R3 and R4. It is erected.

  Specifically, as shown in FIG. 12, which is a longitudinal sectional view in the vicinity of one end of the holding shaft 104a, two elongated hole-like bolt insertion holes 106a are provided in a portion of the base 102 where the holding shaft 104a is erected. 106b and a stepped portion 108 for seating that is continuous with the elongated hole insertion holes 106a and 106b and is slightly wider.

  On the other hand, bottomed bolt holes 110a and 110b are formed in the holding shaft 104a at positions overlapping with the elongated hole insertion holes 106a and 106b, respectively.

  The elongated hole insertion holes 106a and 106b can pass through the screw portions 114a and 114b of the holding bolts 112a and 112b, but are set narrower than the heads 116a and 116b. Therefore, when the screw portions 114a and 114b of the holding bolts 112a and 112b inserted into the elongated bolt insertion holes 106a and 106b from the seating stepped portion 108 side are screwed into the bolt holes 110a and 110b, the head portion 116a and 116b is seated on the stepped portion 108 for seating. By this seating, further progress of the clamping bolts 112a and 112b is suppressed.

  By further tightening the clamping bolts 112a and 112b from this state, the base 102 is firmly clamped by the heads 116a and 116b of the clamping bolts 112a and 112b and the holding shaft 104a. As a result, the holding shaft 104a is positioned and fixed.

  The position shown in FIG. 12 corresponds to the position shown by the solid line in FIG. As can be understood from FIG. 11 and FIG. 12, in this case, the holding shaft 104a is at a position farthest from the center of the metal ring R3. In other words, the holding shaft 104a is located at the backward movement end.

  Of course, the holding shafts 104b to 104d and 104f to 104i are similarly positioned and fixed to the base 102. Therefore, as easily understood from FIG. 11, the diameters of the inscribed circle formed by the holding shafts 104a to 104e and 104j and the inscribed circle formed by the holding shafts 104e to 104j are maximized.

  Therefore, in this case, it is possible to hold large diameter metal rings R3 and R4.

  When holding the metal rings R5 and R6 having a smaller diameter than the metal rings R3 and R4, the following may be performed.

  First, the clamping bolts 112a and 112b are loosened, and the heads 116a and 116b of the clamping bolts 112a and 112b are separated from the seating step 108. As a result, the holding bolts 112a and 112b release the base 102, so that the holding shafts 104a to 104d and 104f to 104i can be displaced.

  Next, as shown in FIG. 13, the holding shafts 104 a to 104 d and 104 f to 104 i are displaced in directions toward each other (advance end). As a result, as indicated by phantom lines in FIG. 11, the diameters of the inscribed circle formed by the holding shafts 104a to 104e and 104j and the inscribed circle formed by the holding shafts 104e to 104j are reduced. That is, the holding shafts 104a to 104d and 104f to 104i are displaced in a direction in which the diameter of the inscribed circle is reduced.

  Thereafter, the clamping bolts 112a and 112b are retightened at the positions shown in FIG. 13, that is, at the end portions (advanced ends) of the elongated hole insertion holes 106a and 106b, and the heads 116a and 116b of the clamping bolts 112a and 112b are fastened. The base 102 is sandwiched between the heads 116a and 116b and the holding shafts 104a to 104j while being seated on the stepped portion 108 for seating. Thus, the holding shafts 104a to 104d and 104f to 104i are positioned and fixed at the forward end.

  Thereafter, as described in the first embodiment, the first row L5 may be held by the holding shafts 104a to 104e and 104j, and the second row L6 may be held by the holding shafts 104e to 104j.

  As described above, according to the second embodiment in which the holding shafts 104a to 104d and 104f to 104i are erected on the base 102 so as to be displaceable, the metal rings R3 and R4 and the metal rings R5 and R6 have various diameters. It becomes possible to hold the metal ring.

  The longitudinal dimension of the elongated hole insertion holes 106a and 106b is preferably set according to the diameter of the metal ring R3 (R4) and the diameter of the metal ring R5 (R6).

  That is, as described above, the metal rings R3 and R4 can be held at the positions where the holding shafts 104a to 104d and 104f to 104i are the backward ends (see the solid line in FIG. 11), and the positions that are the forward ends. Thus, it is preferable to set the longitudinal dimension of the elongated hole insertion holes 106a and 106b so that the metal rings R5 and R6 can be held (see the phantom line in FIG. 11). In this case, without measuring the displacement distance of the holding shafts 104a to 104d and 104f to 104i each time, to the appropriate position according to the diameter of the metal ring R3 (R4) and the diameter of the metal ring R5 (R6), This is because the holding shafts 104a to 104d and 104f to 104i can be displaced.

  The holding shafts 104a to 104d and 104f to 104i are positioned and fixed between the forward end position and the reverse end position, and have a smaller diameter than the metal rings R3 and R4 and a larger diameter than the metal rings R5 and R6. Needless to say, the metal ring may be held.

  By the way, when heat processing is performed in the heat processing furnace 80 (refer FIG. 8), the conveyance rack 100 heats up and becomes high temperature. Although the transport rack 100 undergoes thermal expansion due to this heat, the vicinity of the holding shafts 104e and 104j tends to expand more than the vicinity of the holding shafts 104a to 104d and 104f to 104i. This is because the holding shafts 104a to 104d and 104f to 104i hold only one of the first row L3 and the second row L4, while the holding shafts 104e and 104j have the first row L3 and the second row L4. Therefore, it is assumed that the amount of heat transmitted from the metal rings R3 and R4 is larger in the holding shafts 104e and 104j than in the holding shafts 104a to 104d and 104f to 104i. The

  As a result, the base plate 102 and the connection board 16 that sandwich the holding shafts 104a to 104i may bend so as to approach each other toward the end side away from the holding shafts 104e and 104j. Since the base 102 and the connection board 16 are bent in this manner, the holding shafts 104 a to 104 d and 104 f to 104 i are firmly sandwiched between the base 102 and the connection board 16.

  As shown in FIG. 11, for example, when heat treatment is performed on the metal rings R5 and R6 having a smaller diameter after the heat treatment is performed on the metal rings R3 and R4, the holding shafts 104a to 104d and 104f to 104i. Need to be displaced in the direction in which they approach each other. However, as described above, the holding shafts 104a to 104d and 104f to 104i are sandwiched (restrained) by the base plate 102 and the connecting board 16 which are bent so as to approach each other, and thus are not easily displaced. .

  In this case, for example, it is recalled that all the bolts 40 (see FIG. 1) that connect the holding shafts 104a to 104j to the connecting board 16 are relaxed. This is because all of the holding shafts 104a to 104j are released from the holding of the base plate 102 and the connecting board 16, so that the holding shafts 104a to 104d and 104f to 104i can be easily displaced. Then, after the displacement is finished, the bolt 40 is tightened again.

  However, in this case, since all the bolts 40 are loosened and retightened, it takes a long time to start the heat treatment of the metal rings R5 and R6 after releasing the metal rings R3 and R4. In other words, processing efficiency decreases. Further, it is necessary to align the bolt insertion hole 38 (see FIG. 1) of the connecting board 16 with the bolt hole formed in the tip surface of the holding shafts 104a to 104j. Loss.

  Therefore, as shown in FIG. 14 which is a front view, it is preferable to make the height direction dimension (axis direction dimension) of the holding shafts 104a to 104d and 104f to 104i smaller than the holding shafts 104e and 104j. The height dimension may be made smaller as the distance from the holding shafts 104e and 104j increases. FIG. 14 omits illustration of the metal rings R3 and R4 for easy understanding, and exaggerates the difference in dimension in the height direction.

  In this case, when the base plate 102 and the connection board 16 are connected to all of the holding shafts 104a to 104j, the base board 102 and the connection board 16 are bent so as to approach each other (see FIG. 14). In this state, even if the metal rings R3 and R4 held on the holding shafts 104a to 104j are subjected to heat treatment, the base plate 102 and the connecting board 16 hardly bend further.

  Then, after the heat-treated metal rings R3 and R4 are removed from the holding shafts 104a to 104j, when the heat treatment is performed on the small-diameter metal rings R5 and R6 instead, as shown in FIG. The bolts 112a and 112b (see FIGS. 12 and 13) for connecting the shafts 104a to 104d and 104f to 104i and the base plate 102 are loosened, and the bolts for connecting the holding shafts 104a to 104d and 104f to 104i to the connecting board 16 Loosen 40. At this time, the base 102 and the connecting board 16 try to return to a shape extending in the horizontal direction due to elasticity.

  That is, the base 102 and the connecting board 16 warp in the direction in which the holding shafts 104a to 104d and 104f to 104i are separated. Thereby, since the holding shafts 104a to 104d and 104f to 104i are released from the restraint of the base plate 102 and the connecting board 16, the holding shafts 104a to 104d and 104f to 104i can be easily displaced.

  15 shows a state in which the bolt 40 is detached from the holding shafts 104a to 104d and 104f to 104i. However, the holding shafts 104a to 104d and 104f to 104i are released from the restraint of the base plate 102 and the connecting board 16. It is sufficient to loosen the bolt 40 to such an extent that it is not necessary to remove it.

  After the holding shafts 104a to 104d and 104f to 104i are displaced, the clamping bolts 112a and 112b (see FIGS. 12 and 13) and the bolt 40 are tightened again. As a result, the holding shafts 104 a to 104 d and 104 f to 104 i are re-constrained by the base 102 and the connecting board 16.

  On the other hand, in the holding shafts 104e and 104j, the bolt 28 (see FIGS. 4 and 11) and the bolt 40 (see FIG. 1) are not loosened. Inevitably, it is not necessary to retighten the bolts 28 and 40 to the holding shafts 104e and 104j. As described above, the relaxation / re-tightening operation time can be shortened by not releasing the restraint of the base plate 102 and the coupling board 16 with respect to the holding shafts 104e and 104j.

  In addition, in this case, the position of the bolt insertion hole 38 (see FIG. 1) of the connecting board 16 and the position of the bolt hole formed in the tip surface of the holding shafts 104a to 104d and 104f to 104i remain substantially matched. . As described above, the state in which the holding shafts 104e and 104j are connected to the base 102 and the connecting board 16 is maintained, so that it is avoided that the bolt insertion hole 38 and the bolt hole are misaligned. Therefore, the work time required for alignment can also be shortened.

  As described above, the height dimension of the holding shafts 104e and 104j that hold both the two rows of metal rings R3 and R4 (R5 and R6) is set to either the metal ring R3 (R5) or the metal ring R4 (R6). By setting the holding shafts 104a to 104d and 104f to 104i to hold only one of them, the holding shafts 104a to 104d and 104f to 104i can be easily displaced, and the metal rings R3 and R4 can be moved. It becomes possible to shorten the time from the release until the metal rings R5 and R6 are held. Therefore, the processing efficiency of the metal rings R5 and R6 can be improved.

  Furthermore, as shown in FIG. 16, the holding shafts 104 e and 104 j may also be erected so as to be displaceable with respect to the base 102. In this case, which is a modification according to the second embodiment, elongated hole bolt insertion holes 106a and 106b and a seating step 108 (FIG. 12) are provided in the same manner as described above at the portions where the holding shafts 104e and 104j are erected on the base 102. And FIG. 13).

  The screw portions 114a and 114b of the holding bolts 112a and 112b are screwed into the bolt holes 110a and 110b formed at the lower end portions of the holding shafts 104e and 104j, and the head portions 116a and 116b seated on the seating stepped portion 108. Then, the substrate 102 may be held between the holding shafts 104e and 104j. Thereby, the holding shafts 104e and 104j are positioned and fixed.

  When the holding shafts 104e and 104j are displaced, the base 102 may be released by loosening the clamping bolts 112a and 112b, as described above.

  In FIG. 16, the holding shafts 104a to 104d are set to the backward end positions, the holding shafts 104g to 104i are set to the forward end positions, and the holding shafts 104e and 104j are further displaced in a direction approaching the holding shafts 104g to 104i. The state which was made to illustrate is illustrated. In this case, as indicated by phantom lines in FIG. 11, the diameter of the inscribed circle formed by the holding shafts 104a to 104e and 104j is larger than the diameter of the inscribed circle formed by the holding shafts 104e to 104j. Become.

  As can be understood from this, in this case, the metal ring R7 (first row L7) held by the holding shafts 104a to 104e, 104j and the metal ring R8 (first row) held by the holding shafts 104e to 104j. It is possible to select two rows L8) having different diameters.

  Also in this case, as a matter of course, the holding shafts 104a to 104j may be positioned and fixed between the forward end position and the backward end position as necessary.

  Of course, also in the second embodiment described above, the damming projection 32 holds the metal rings R3 to R8 in a state where the expansion force is generated in a pressed state. Therefore, also in the second embodiment, as in the first embodiment, it is possible to avoid the occurrence of distortion in the metal rings R3 to R8 during the heat treatment.

  In both the first embodiment and the second embodiment, the transport rack may be configured by only the base 12 and the holding shafts 14a to 14j without using the connecting board 16.

  In the first and second embodiments, ten holding shafts 14a to 14j and 104a to 104j hold two of the metal rings R1 to R8 as two rows of the first row L1 and the second row L2. However, when two rows are held as described above, at least four holding shafts are sufficient.

  Furthermore, the metal rings R1 to R8 that serve as the CVT belt are exemplified as the workpiece and the nitriding treatment is exemplified as the treatment, but the workpiece and the heat treatment are not particularly limited thereto. For example, when a ring member that requires carburizing treatment is used as a workpiece, the carburizing gas may be supplied instead of the nitriding gas.

  Furthermore, the metal rings R1 to R8 may be sandwiched between the adjacent mounting projections 30 and 30. Also in this case, the amount of heat transfer from the metal rings R1 to R8 to the mounting protrusion 30 is minimized by making the contact between the metal rings R1 to R8 and the mounting protrusions 30 and 30 point contact. Can be suppressed.

  The holding shafts 14a to 14j and 104a to 104j may be hollow bodies. In this case, the transport rack 10 can be further reduced in weight.

DESCRIPTION OF SYMBOLS 10,100 ... Conveyance rack 12,102 ... Base | substrate 14a-14j, 104a-104j ... Holding shaft 16 ... Connection board 30 ... Mounting projection part 32 ... Protrusion part 42 for damming ... Connection pin 80 ... Heat treatment furnace 86,88 ... Heater 92 ... Convection fan 96 ... Agitating blade
106a, 106b ... slotted bolt insertion hole 108 ... seating step 112a, 112b ... clamping bolt L1-L8 ... row R1-R8 ... metal ring

Claims (12)

A transport rack for holding and transporting a plurality of metal rings having elastic restoring force,
The foundation,
A plurality of mounting projections which are provided on the base and extend in parallel with each other and projecting toward the metal ring are provided on the side walls, and the metal is disposed above the mounting projections. A plurality of holding shafts for holding the metal ring by placing the ring;
A damming projection that protrudes from the holding shaft and is interposed between adjacent mounting projections and abuts against the side wall of the metal ring to press the metal ring inward in the diameter direction. And
A transport rack characterized by comprising:   The transport rack according to claim 1, wherein the placement projection is formed as a cylindrical body, and the diameter thereof is set to a size that makes point contact with the metal ring.   3. The transport rack according to claim 1, wherein the plurality of holding shafts are arranged so as to be capable of being held in a state where the metal rings are arranged in two or more rows.   The conveyance rack according to any one of claims 1 to 3, further comprising a connection board that is arranged apart from the base and to which ends of all the holding shafts are connected. rack.   The conveyance rack according to any one of claims 1 to 4, wherein the holding shaft is made of nickel or a nickel-base alloy, or a nickel or nickel-base alloy film is formed on the surface thereof. A transport rack characterized by the above.   The conveyance rack according to any one of claims 1 to 5, wherein at least a part of the plurality of holding shafts has a direction in which a diameter of an inscribed circle formed by the holding shafts increases or decreases. A transport rack, wherein the transport rack is erected on the base so as to be displaceable in a given direction.   7. The transport rack according to claim 6, wherein the plurality of holding shafts are arranged so that they can be held in a state in which the metal rings are arranged in two or more rows, and are arranged apart from the base. The holding shaft further includes a connecting plate to which ends of the holding shaft are connected, and the holding shaft that holds both of the two adjacent rows of the metal rings is positioned and fixed, while the holding shaft that holds only one row of the metal rings. The transport rack is characterized in that the axial dimension of the holding shaft that is displaceable and positioned and fixed is set larger than that of the holding shaft that is displaceable.   7. The transport rack according to claim 6, wherein all of the plurality of holding shafts are displaceable. In order to heat-treat a plurality of metal rings having elastic restoring force, a metal ring that holds the metal rings by a transport rack that is provided on a base and has a plurality of holding shafts extending in parallel with each other. Holding method,
The metal ring is placed above a plurality of placement projections provided on a side wall of the holding shaft, and the damming projections interposed between the placement projections are adjacent to each other. A method of holding a metal ring, wherein the metal ring is held by abutting against a side wall of the metal ring.   The holding method according to claim 9, wherein at least a part of the plurality of holding shafts is displaced in a direction in which a diameter of an inscribed circle formed by the holding shafts increases or decreases. Holding method of metal ring. The holding method according to claim 10, wherein the plurality of holding shafts are arranged so as to be held in a state where the metal rings are arranged in two or more rows in a row, and arranged apart from the base. When providing a connecting plate to which the ends of the holding shaft are connected, the holding shaft holding both of the two adjacent metal rings is positioned and fixed, while the holding shaft holding only one row of the metal rings is displaced. The axial dimension of the holding shaft that is possible and positioned and fixed is set larger than the holding shaft that is displaceable,
A method for holding a metal ring, wherein only the holding shaft that is displaceable is displaced after being released from restraint on the base.   The holding method according to claim 10, wherein all of the plurality of holding shafts are displaced.

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