JP2010229448A - Metal ring heat treatment jig - Google Patents

Abstract

An object of the present invention is to provide an excellent metal ring heat treatment jig which is excellent in the heat followability of a jig during heat treatment such as aging treatment and nitriding treatment and can reduce the diameter change rate of the metal ring by heat treatment.
In a heat treatment jig in which three or more parallel metal ring holding members are erected in a vertical direction and a plurality of metal rings having restoring force are held in parallel inside thereof, the metal ring is held. The member is a plate-like member that is provided with projections at regular intervals only on the surface facing the metal ring, and extends in the back direction from the surface on which the projection is provided, and the outer peripheral edge of the metal ring is It is sandwiched between adjacent protrusions.
[Selection] Figure 2

Description

  The present invention relates to a jig for heat treatment while holding a plurality of metal rings in an endless metal belt used in a continuously variable transmission (CVT) or the like.

  A continuously variable transmission used as a transmission for an automobile or the like includes an endless belt-like metal belt that is wound around a pair of pulleys. This endless belt-like metal belt uses a pair of laminated metal rings obtained by laminating a plurality of endless belt-like metal rings having different circumferential lengths in the thickness direction, and by engaging these pair of laminated metal rings from the width direction, This is a configuration in which a large number of plate-like elements are arranged in an annular shape in the thickness direction.

  Said metal ring is manufactured as follows. First, both ends of a thin plate of a steel material such as maraging steel or stainless steel are welded so as to be cylindrical. At this time, since a part of the steel material is hardened by the heat of welding, the cylindrical steel material is solutionized and homogenized. Next, this solution-formed cylindrical steel material is cut into a predetermined width to form an endless belt-like ring, and then rolled to a predetermined thickness. Since the metal structure is deformed by the rolling, the rolled ring is again formed into a solution to recrystallize the metal structure. After that, the solution ring is corrected to a predetermined peripheral length, and metal rings with different peripheral lengths are manufactured little by little, and further, aging treatment and nitriding treatment are performed to improve hardness and wear resistance. .

  As the nitriding treatment, there are known a gas nitriding method, a gas soft nitriding method, a salt bath nitriding method, and the like for holding a metal ring in a predetermined atmosphere for a predetermined time. In this gas nitriding method or gas soft nitriding method, it is preferable that the entire metal ring is exposed to the atmosphere, whereby the metal ring is uniformly nitrided.

  In such a nitriding treatment of a metal ring, a jig is used that can hold a large number of metal rings and nitride them at a time. Specifically, a metal ring nitriding jig for suspending a metal ring in a vertical direction from the inner peripheral surface side to a pair of upper and lower suspension means has been reported (for example, see Patent Document 1). However, in this nitriding jig, since the metal ring is suspended, the metal ring is unstable in the heating furnace, and the filling rate of the metal ring in the heating furnace is low. There was a problem that the weight of the hitting jig was large and the thermal efficiency during heat treatment was poor. Furthermore, there is a problem that the load is concentrated on the metal ring that is in contact with the upper suspension means, and deformation of the metal ring occurs when nitriding is performed.

  Also, a frame that can be inserted in the radial direction of the metal ring is provided, and the metal ring is pressed from the outer peripheral surface side and held in an elliptical shape by a plurality of holding members provided in the frame. A nitriding jig for a metal ring has been reported (for example, see Patent Document 2). However, even in this nitriding jig, since the metal ring is held in an elliptical shape in the vertical direction, problems such as deformation of the metal ring due to nitriding have not been solved. In addition, the above-described deformation and the like may be corrected together with the correction of the peripheral length in the peripheral length correction process. However, when the deformation or the like is large, in order to correct this deformation together with the correction of the peripheral length. There is a problem that it takes too much time.

  Therefore, to solve this problem, three or more parallel rods are erected in the vertical direction, and a number of double conical ring seats protruding in the horizontal direction are provided on the rods. A metal ring transport rack has been reported in which a metal ring is sandwiched from an outer peripheral surface side into a V-shaped recess formed by an inclined surface of an adjacent ring seat when a ring is inserted (for example, Patent Documents). 3). However, in this transport rack, the heat followability of the transport rack during heating is inferior, and the diameter change rate of the metal ring during heat treatment may increase, and this deformation is corrected together with the correction of the circumference. There was a problem that it took too much time. In addition, the diameter change rate of the metal ring in the present invention is a percentage of the diameter reduction of the metal ring by the heat treatment with respect to the diameter of the metal ring in a circular posture.

JP 2002-161314 A Japanese Patent No. 4219186 JP 2008-240085 A

  Therefore, in view of the above problems, the present invention is excellent in heat followability of a jig during heat treatment such as aging treatment and nitriding treatment, and excellent metal ring heat treatment capable of reducing the metal ring diameter change rate by heat treatment. The purpose is to provide a jig.

  The heat treatment jig for metal rings of the present invention is a heat treatment in which three or more parallel metal ring holding members are erected in the vertical direction, and a plurality of metal rings having restoring force are held in parallel in the inside. In the jig, the metal ring holding member is a plate-like member provided with protrusions at regular intervals only on the surface facing the metal ring and extending in the back direction from the surface where the protrusions are provided. And the outer peripheral edge of the metal ring is sandwiched between the adjacent protrusions.

  According to the present invention, the metal ring holding member in contact with the metal ring can be reduced in size and weight, so that the heat capacity is reduced, heat followability during heat treatment is excellent, and the diameter change rate of the metal ring by heat treatment is reduced. can do. As a result, there is no problem in assembling work when the metal rings are stacked. Further, according to the present invention, the weight of the metal ring holding member, and hence the heat treatment jig can be reduced, so that the power required for transporting the heat treatment jig can be saved.

It is a top view which shows one Embodiment of the heat processing jig | tool of the metal ring of this invention. It is a front view which shows one Embodiment of the heat processing jig | tool of the metal ring of this invention. It is a front view which shows one Embodiment of the metal ring holding member in the heat processing jig | tool of the metal ring of this invention. It is a top view which shows one Embodiment of the metal ring holding member in the heat processing jig | tool of the metal ring of this invention. It is the conceptual diagram shown about the heat processing using the heat processing jig | tool of the metal ring of this invention.

  Hereinafter, embodiments of a heat treatment jig for a metal ring of the present invention will be specifically described with reference to the drawings. FIG. 1 is a top view showing an embodiment of a heat treatment jig for a metal ring of the present invention, and FIG. 2 is a front view thereof. FIG. 3 is a front view showing an embodiment of a metal ring holding member in the heat treatment jig for metal rings of the present invention, and FIG. 4 is a top view thereof. As shown in FIGS. 1 and 2, in the metal ring heat treatment jig of the present invention, three or more parallel metal ring holding members 1 are erected in the vertical direction so as to contact the outer periphery of the metal ring 2. Yes.

  As shown in FIGS. 3 and 4, these metal ring holding members 1 are provided with protrusions 3 at regular intervals only on the surface facing the metal ring 2. The protrusion 3 has an inclined surface, and when the outer periphery of the metal ring 2 is inserted between two adjacent protrusions 3, the outer peripheral edge of the metal ring 2 abuts on the inclined surface. It is a configuration. The metal ring holding member 1 according to the present invention is configured such that when three or more metal ring holding members 1 are installed in parallel, each protrusion is formed at the same height, and between these adjacent protrusions. When the metal ring 2 is inserted into the metal ring 2, the metal ring 2 is held horizontally.

  Moreover, it is essential that the metal ring holding member in this invention is a plate-shaped member extended in the back direction from the surface in which the projection part was provided. By adopting such a configuration, a conventional heat treatment jig, that is, a cylindrical portion, a protruding portion that is concentric with the cylindrical portion, protrudes from the cylindrical portion, and the protruding portion from the cylindrical portion that sandwiches the protruding portion up and down. The heat capacity can be remarkably reduced as compared with a jig provided with a metal ring holding member having a concentric tapered portion of the cylindrical portion formed by expanding toward The diameter of the metal ring due to heat treatment can be reduced. As an experimental example of weight reduction, a weight reduction of about 20% is realized.

  Furthermore, the metal ring holding member in the present invention is preferably a hollow member. By making the metal ring holding member hollow, the weight can be further reduced, and when the heat treatment is performed, an already heated atmosphere is introduced into the hollow portion, so that the heat followability during the heat treatment can be further improved. Can be improved. As an example of weight reduction, a weight reduction of about 40% and a weight reduction of about 14% per jig are realized.

  In the heat treatment jig of the present invention having such a configuration, a metal ring is placed as follows. First, the substantially circular metal ring 2 is pressed in the radial direction to be deformed into a substantially elliptical shape, and the radial direction is horizontally inserted inside the three or more metal ring holding members 1 while maintaining this state. To do. Here, when the pressing of the metal ring 2 is released, the substantially elliptical shape is returned to the substantially circular shape by the elastic force of the metal ring 2, and the surface of the metal ring holding member 1 on which the protrusion 3 is provided. The outer periphery of the metal ring 2 approaches. Then, while controlling the horizontal arrangement so that the outer periphery of the metal ring 2 is inserted between the adjacent protrusions 3 of each metal ring holding member 1 provided at the same height, the pressing of the metal ring 2 is further released. As a result, the outer peripheral edge of the metal ring 2 is sandwiched between the adjacent protrusions 3 of the metal ring holding member 1, and the metal ring 2 is held horizontally. By repeating this metal ring placement method, a number of metal rings can be held in parallel in the metal ring heat treatment apparatus of the present invention.

  As described above, the heat treatment jig in which a large number of metal rings 2 are arranged in parallel is singly or stacked on a plurality of pallets using the positioning projections 4 and the positioning recesses 5, and is carried into an aging and nitriding furnace. A predetermined heat treatment is performed. Since aging and nitriding are performed in a continuous furnace, transfer between the furnaces can also be performed for each heat treatment jig of the present invention. When the nitriding treatment is gas nitriding, the furnace is a batch type, so the metal ring filling rate in the jig greatly affects the heat treatment efficiency.

  In the metal ring heat treatment jig of the present invention, it is preferable that two or more sets of metal ring holding members for horizontally arranging a large number of metal rings are provided per jig. By setting it as such a structure, the jig weight per number of metal rings can be reduced, and the thermal efficiency at the time of heat processing can be improved. As an experimental example, the jig weight and volume per number of metal rings could be reduced by about 9% and about 10% compared to a heat treatment jig provided with one set of metal ring holding members per jig. .

  When two or more metal ring holding members are provided per jig as described above, each metal ring placed on each metal ring holding member is opposed to each metal ring at the closest position. As described above, a metal ring holding member having protrusions on both sides of the member may be provided to hold both sets of metal rings at the same time. According to such a configuration, the number of metal ring holding members used in the heat treatment jig of the present invention can be reduced, and the weight of the heat treatment jig can be reduced.

  The metal ring heat treatment jig of the present invention is preferably nickel-plated. When the heat treatment jig of the present invention is manufactured from a material containing Cu, Cr, etc., the uniform nitriding reaction of the metal ring may be hindered at the portion in contact with the jig. is there. Needless to say, the metal ring holding member may be made of pure nickel.

  Furthermore, in the metal ring heat treatment jig of the present invention, it is preferable that the metal ring holding member is arranged so that the placed metal ring has a substantially circular shape. This is because a metal ring that has been subjected to heat treatment in a substantially elliptical shape remains affected by the shape at the time of heat treatment, which may cause inconvenience when used in a substantially circular shape.

  Further, in the metal ring heat treatment jig of the present invention, three or more parallel metal ring holding members 1 are erected in the vertical direction on the plate-like bottom portion, and a large number of metal ring holding members 1 are disposed inside these metal ring holding members 1. After placing the metal ring, the plate-like lid may be placed on the ceiling, but in order to improve the thermal efficiency during heating, an opening is provided in the plate-like bottom and lid It is possible to reduce the weight. In order to further reduce the weight, the heat treatment jig of the present invention may have a frame shape in which three or more parallel metal ring holding members 1 are incorporated in the vertical direction. In this configuration, it is possible to place the metal ring 2 from the upper opening without providing the bottom and the lid.

  The metal ring 2 in the present invention is an endless belt-like metal ring having elasticity, and is welded so that both ends of a thin plate of a steel material such as maraging steel and stainless steel become cylindrical, and is hardened by the heat of welding. In order to recrystallize the metal structure after rolling the metal ring into a predetermined thickness by cutting it into a predetermined width, and then rolling the metal ring to a predetermined thickness. The solution was made into a solution and the circumference was corrected as necessary. The metal ring 2 has a substantially annular shape when no external force is applied.

Next, the heat treatment performed using the heat treatment jig of the present invention will be specifically described.
The heat treatment jig 10 of the present invention on which the metal ring 2 is placed is conveyed into the heat treatment furnace 11 shown in FIG. 5 by a conveying means (not shown). In addition, the metal ring holding member 1 in this embodiment used the hollow member provided with the opening in both ends. In the heat treatment jig 10 in the heat treatment furnace 11, the inside of the metal ring holding member 1, which is a hollow body, and the inside of the heat treatment furnace 11 are in communication with each other through the openings. The heat treatment furnace 11 is formed in a long shape along the conveying direction of the heat treatment jig 10, heaters 14 and 15 are installed inside the side walls 12 and 13, and a stirring blade 17 is provided on the ceiling wall 16. A convection fan 18 is installed.

  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 the heat treatment furnace 11 shown in FIG. The nitriding gas is heated by the heaters 14 and 15 to a predetermined temperature at which the metal ring 2 can be nitrided, for example, about 500 ° C. The heated nitriding gas rises toward the ceiling wall 16 of the heat treatment furnace 11. The rising nitriding gas is convected in the heat treatment furnace 11 by rotating the stirring blade 17 of the convection fan 18.

  As a result, the nitriding gas descends along the side walls 12 and 13 and then tries to rise again in the vicinity of the floor of the heat treatment furnace 11 and eventually in the vicinity of the heat treatment jig 10. Here, as described above, the inside of the metal ring holding member 1 is in communication with the inside of the heat treatment furnace 11 through the openings at both ends. Therefore, the nitriding gas is introduced from the opening below the metal ring holding member 1 as shown in FIG. That is, in this case, the lower opening of the metal ring holding member 1 is directed upstream in the flow direction of the nitriding gas and functions as an inlet for the nitriding gas. After passing through the inside of the metal ring holding member 1, the nitriding gas is discharged from the upper opening and directed toward the ceiling wall 16 of the heat treatment furnace 11.

  As described above, in the present embodiment in which the metal ring holding member 1 is a plate-like member and the inside of the metal ring holding member 1 is a hollow member that is in communication with the atmosphere, the metal ring holding member 1 is placed inside the metal ring holding member 1 during nitriding treatment. While the heated nitriding gas is circulated, the nitriding gas heated to the same extent as the inside exists also outside the metal ring holding member 1. That is, the nitriding gas heated to the same extent exists both inside and outside the metal ring holding member 1. For this reason, the temperature balance is maintained inside and outside the metal ring holding member 1, and as a result, the temperature of the metal ring 2 becomes substantially uniform throughout. In other words, the temperature of the contact point between the metal ring holding member 1 and the metal ring 2 is substantially equal to the temperature of other portions of the metal ring 2. Then, the nitriding gas enters from the surface of the metal ring 2 and diffuses inside, thereby forming a nitride layer on the surface of the metal ring 2. That is, so-called nitriding proceeds. The metal ring 2 is cured by the nitride layer.

  As described above, the temperature of the metal ring 2 is substantially uniform throughout. Therefore, nitriding proceeds approximately equally throughout the entire metal ring 2. That is, by using the heat treatment jig of the present invention, the thermal followability during the heat treatment is improved, and variation in the nitriding progress is avoided, resulting in variations in the thickness of the nitrided layer and hence the degree of curing. This is also avoided, and the diameter change rate of the metal ring due to heat treatment is reduced.

DESCRIPTION OF SYMBOLS 1 ... Metal ring holding member, 2 ... Metal ring, 3 ... Projection part, 4 ... Positioning convex part,
5 ... Positioning recess, 10 ... Heat treatment jig, 11 ... Heat treatment furnace, 12, 13 ... Side wall,
14, 15 ... heater, 16 ... ceiling wall, 17 ... stirring blade, 18 ... convection fan

Claims (3)

3 or more parallel metal ring holding members are erected in the vertical direction,
In the heat treatment jig that holds a large number of metal rings having a restoring force inside these in parallel,
The metal ring holding member is a plate-like member provided with protrusions at regular intervals only on the surface facing the metal ring, and extending in the back direction from the surface provided with the protrusions.
A heat treatment jig for a metal ring, wherein an outer peripheral edge of the metal ring is sandwiched between adjacent protrusions.   The heat treatment jig for metal rings according to claim 1, wherein the metal ring holding member is a hollow member.   The metal ring holding member according to claim 1, wherein two or more sets of the metal ring holding members are provided per jig.

Images