JP3776306B2 - Metal ring nitriding jig - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a jig used for nitriding a metal ring used as a material for an endless metal belt used in a continuously variable transmission or the like.
[0002]
[Prior art]
A belt of a continuously variable transmission (CVT) used as a transmission of an automobile or the like is configured by a laminated ring that is formed by laminating a plurality of endless metal rings in the thickness direction. The metal ring is manufactured by the following method.
[0003]
First, a cylindrical drum by welding the ends of the thin plate of maraging steel is ultra high strength steel, homogenized partially hardened hardness by heat during the welding with respect to the drum In order to do so, the first solution treatment is performed. Next, the solution-treated drum is cut into a predetermined width to form a ring, and the ring is rolled. Next, in order to recrystallize the rolled structure on the rolled ring and restore the shape of the metal structure deformed by rolling, a second solution treatment is performed. Then, after the solution ring is corrected to a predetermined circumferential length and subjected to aging treatment and nitriding treatment to improve the hardness, a plurality of rings having different circumferential lengths are laminated to each other little by little. Form.
[0004]
As the nitriding treatment, a gas nitriding method, a gas soft nitriding method, a salt bath nitriding method, and the like are known. The gas nitriding method or the gas soft nitriding method is performed by holding the metal ring in a predetermined atmosphere for a predetermined time. Done. Conventionally, in the gas nitriding method or the gas soft nitriding method, a jig for vertically suspending the ring is used. As a material for the jig, Ni-Cu alloy, SUS304 material, or the like is used.
[0005]
However, when the ring is suspended from the conventional jig and nitriding is performed by gas nitriding or gas soft nitriding, the ring is not uniformly nitrided or the ring is in contact with the jig. There is an inconvenience that contact marks may be formed in the portion.
[0006]
[Problems to be solved by the invention]
An object of the present invention is to provide a nitriding jig capable of solving such inconvenience and obtaining a metal ring having an excellent quality by a gas nitriding method or a gas soft nitriding method.
[0007]
[Means for Solving the Problems]
According to the study by the present inventors, the reason why the ring is not nitrided uniformly in the nitriding process by the gas nitriding method or the gas soft nitriding method is that a part of the metal component contained in the jig inhibits the nitriding reaction. This is probably because of this. In addition, when a component that inhibits the nitriding reaction is present in a part of the metal component contained in the jig as described above, the portion that has been in contact with the jig becomes difficult to undergo nitridation. Is considered to be formed.
[0008]
Examples of the metal component contained in the jig and inhibiting the nitriding reaction include Cu contained in the Ni—Cu alloy, Cr contained in the SUS304 material, and the like. In order to avoid the influence of the nitriding of the metal component, it is conceivable that the entire jig is made of Ni, W, or Mo, which is difficult to be nitrided. Not suitable, W and Mo have a difference in thermal expansion coefficient with respect to maraging steel, are difficult to process, and are expensive.
[0009]
Therefore, the nitriding jig of the present invention is a ring formed by cutting a cylindrical drum formed by welding end portions of maraging steel thin plates to a predetermined width in order to achieve such an object. A jig used for the nitriding treatment of the above-mentioned is characterized in that it comprises suspension means for suspending a ring, and pure nickel is disposed on a portion of the suspension means that contacts the ring.
[0010]
According to the nitriding jig of the present invention, pure nickel which is not easily nitrided is disposed in a portion where the suspension means contacts the ring, so that the metal ring suspended by the suspension means is uniformly nitrided. And the formation of contact marks can be reduced. Pure nickel has a thermal expansion coefficient similar to that of maraging steel, which is the material of the metal ring, so that the metal ring is prevented from being distorted due to a difference in thermal expansion between the jig and the metal ring. be able to.
[0011]
As the pure nickel provided in the portion of the suspension means that contacts the ring, net-like pure nickel can be used. By arranging the net-like pure nickel, the contact area between the metal ring and pure nickel is reduced, and the formation of the contact marks can be further reduced.
[0012]
Pure nickel provided on the part of the suspension means that contacts the ring can be provided by nickel plating on the part, but the nickel plating may be peeled off during use. is necessary.
[0013]
In the nitriding jig of the present invention, when a plurality of the metal rings having different circumferences are concentrically overlapped and suspended on the suspension means, net-like pure nickel is disposed between the metal rings. It is characterized by that.
[0014]
In the nitriding jig of the present invention, by arranging net-like pure nickel between the metal rings, contact between the metal rings can be prevented, and both metal rings can be nitrided uniformly. At the same time, the formation of contact marks can be reduced. Therefore, the number of metal rings that can be processed at one time per suspension means can be increased.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. FIG. 1 is a process diagram schematically showing a main part of a metal ring manufacturing process, FIG. 2 is a front view showing a configuration example of a nitriding jig of this embodiment, and FIG. 3 (a) shows FIG. FIG. 3B is an enlarged view of a portion A of FIG. 3A, and FIG. 4 is a front view showing another configuration example of the nitriding jig of this embodiment. It is.
[0016]
When manufacturing a metal belt used for a belt of a continuously variable transmission or the like, first, as shown in FIG. 1, a maraging steel thin plate 1 is bent to form a loop, and then the ends are welded to form a cylinder. A drum 2 is formed. At this time, since the maraging steel exhibits age hardening by the heat of welding, a portion having high hardness appears on both sides of the welded portion 2a of the drum 2 and affects the rolling process.
[0017]
Therefore, next, the drum 2 is accommodated in the vacuum furnace 3 and held at a predetermined temperature for a predetermined time, thereby performing a first solution treatment to make the hardness uniform. When the first solution treatment is completed, the drum 2 is unloaded from the vacuum furnace 3 and cut into a predetermined width to form the ring 4.
[0018]
The ring 4 formed as described above is then rolled at a reduction rate of 40 to 50%, and then stored in the heating furnace 5 and held at a predetermined temperature for a predetermined time to perform a second solution, The shape of the metal structure deformed by the rolling is restored to the shape before the rolling.
[0019]
When the second solution treatment is completed, the ring 4 is unloaded from the heating furnace 5, and the ring 4 is stretched over a driving roller and a driven roller (not shown) to apply tension, and the ring 4 is rotated by the driving roller. However, the circumference is corrected by applying a load in a direction orthogonal to the traveling direction of the ring 4. The ring 4 is extended to a predetermined circumference by the circumference correction.
[0020]
The ring 4 subjected to the circumference correction is then housed in a heat treatment apparatus (not shown) and subjected to an aging treatment and a nitriding treatment, and then a plurality of rings 4 having different circumferences are stacked on each other little by little. Thus, a laminated ring is formed.
[0021]
The nitriding jig of this embodiment transports the ring 4 subjected to the circumference correction to the heat treatment apparatus, accommodates the ring 4 in the heat treatment apparatus, applies an aging treatment to the ring 4, and performs a predetermined process. It is used for performing nitriding treatment such as gas nitriding and gas soft nitriding in an atmosphere.
[0022]
As shown in FIG. 2, the nitriding jig of the first aspect of the present embodiment is attached to a pole 12 which is erected on a base 11 so as to be rotatable, and to protrude horizontally above and below the pole 12 in the horizontal direction. And a pair of upper and lower suspension members 14 attached to the tip of the arm 13. Each of the upper and lower suspension members 14 is inclined to the pole 12 side so that the front end portions 14a thereof face each other, and the ring 4 is attached to the front end portion 14a in the width direction as shown in the side view of FIG. A holding member 15 having a V-shape in a plan view is provided. The clamping member 15 can be held in a state in which the ring 4 is pressed against the inner peripheral surface of the ring 4 and tension is applied to the ring 4. The sandwiching member 15 is provided in a saw blade shape by connecting five each on the left and right sides of the pole 12 so that ten rings 4 can be suspended at a time.
[0023]
The nitriding jig of this embodiment is made of a Ni—Cu alloy, SUS304, or the like, and a net-like member 16 made of pure Ni is disposed on the pinching member 15 of the tip portion 14a that comes into contact with the ring 4. The ring 4 is suspended via the member 16. Therefore, when the nitriding treatment is performed in the heat treatment apparatus, the ring 4 can be uniformly nitrided, and the occurrence of contact traces can be reduced to obtain an excellent quality ring 4.
[0024]
Next, the nitriding jig of the second aspect of the present embodiment is the nitriding jig device 15 shown in FIG. 2 and FIG. 3, in which a plurality of rings 4a and 4b having different circumferential lengths are concentrically overlapped and sandwiched 15 It is intended to be suspended on. At this time, the net-like member 16 is disposed on the clamping member 15 as shown in FIG. 3 (b), and the entire circumference is made of pure Ni between the rings 4a and 4b as shown in FIG. A mesh member 17 is provided.
[0025]
According to the nitriding jig of this embodiment, the rings 4a and 4b can be prevented from contacting each other, and the nitriding of both the rings 4a and 4b can be performed uniformly, and the formation of contact marks can be reduced. Therefore, the number of rings 4a and 4b that can be processed at one time is increased per suspension means, and the processing can be performed efficiently.
[Brief description of the drawings]
FIG. 1 is a process diagram schematically showing a main part of a metal ring manufacturing process.
FIG. 2 is a front view showing a configuration example of a nitriding jig of the present invention.
3A is a side view of the main part of the nitriding jig shown in FIG. 2, and FIG. 3B is an enlarged view of part A of FIG. 3A.
FIG. 4 is a front view showing another configuration example of the nitriding jig of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Thin plate of maraging steel, 2 ... Drum, 4 ... Ring, 14 ... Suspension means 16, 17 ... Net-like pure nickel.

Claims (3)

A jig used for nitriding a ring formed by cutting a cylindrical drum formed by welding ends of thin plates of maraging steel to a predetermined width,
A metal ring nitriding jig comprising a suspension means for suspending a ring, and pure nickel is disposed on a portion of the suspension means that contacts the ring. 2. The metal ring nitriding jig according to claim 1, wherein a net-like pure nickel is disposed on a portion of the suspension means that contacts the ring. The net-like pure nickel is disposed between the metal rings when the plurality of metal rings having different circumferential lengths are concentrically overlapped and suspended on the suspension means. 2. A metal ring nitriding jig according to item 2.

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