JPH05228569A - Forming method of mg alloy wheel for vehicle use - Google Patents

Abstract

PURPOSE:To improve warm workability of a vehicle use wheel by applying solid lubricant on a rim part of die-forged preform and a roller of spinning machine. CONSTITUTION:When a vehicle use Mg alloy wheel is subjected to warm spinning, the solid lubricant is applied on the rim part Mr of the intermediate stock M formed close to the product shape by die forging prior to the spinning. Also the spinning is executed with continuously applying the solid lubricant on the roller 5 of the spinning machine 1 by means of the lubricant nozzle 7 arranged on side of the roller 5. This ensures lubrication between a material to be formed and roller and results in good surface property of warm spinning to improve the productivity and product quality.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for molding a magnesium alloy wheel for vehicles.

[0002]

2. Description of the Related Art In recent years, aluminum alloy wheels have been sequentially mounted on vehicles such as passenger cars, buses and trucks in order to reduce their weight. Further, as the aluminum alloy wheels for these vehicles, one-piece type aluminum wheels have been developed from the viewpoints of structural strength and weight reduction, and many have been put to practical use.

On the other hand, a magnesium alloy having a specific gravity of about 2/3 that of an aluminum alloy and having the same strength has attracted attention as a lightweight material from the past, and various methods have been investigated for forming methods capable of overcoming the inferior property at room temperature processability. Although it has been advanced, in recent years, a technique for forming this magnesium alloy into a one-piece wheel by warm spinning has been developed and put into practical use.

The method disclosed in Japanese Patent Application Laid-Open No. 3-184646 is cited as a method for forming this magnesium alloy wheel,
The outline will be described with reference to FIG. In this forming method, first, a magnesium alloy material is die-forged to produce an intermediate material having a disk portion formed into a final shape and a rim portion roughly formed, and then [Fig. 2]
As shown in, the disk portion Md of the intermediate material M is driven by the spinning molding machine (10) and driven by the mandrel (11),
It is sandwiched by a pair of molds (13), (13 ') attached to the tip of (12), and the intermediate material M is contained in the pair of molds (13), (13'). ), (14 ') while rotating to a temperature of 250 ° C, and pressing its rim portion Mr by the roller (15) against the outer peripheral mold surfaces of the pair of molds (13), (13'). Handle and warm spin mold into the desired wheel shape.

[0005]

By the way, one of the important points in the spinning forming of a metal material is the lubrication between the material and the roller, and when the lubrication between them is insufficient, Baking occurs between the two, and surface defects such as irregularities and scale-like peeling occur on the surface of the metal material to be formed, which deteriorates the quality of the product. For this reason, for example, in cold or warm spinning forming of an aluminum alloy, a water-soluble lubricating oil (emulsion type lubricant) is used also for cooling.

However, in the warm spinning forming of magnesium alloy, these water-soluble lubricating oils cannot be used because magnesium reacts with water to generate heat. In addition, the use of mineral oil as a base oil has a problem of ignition, so that its application is restricted. On the other hand, when performing warm spinning without lubrication, the magnesium alloy has a high affinity with other metals such as tool steel and seizure easily occurs with the roller, so continuous and stable spinning molding can be continued. In addition, the above-mentioned problems of surface defects frequently occur, and high productivity and product quality cannot be maintained.

The present invention has been made to solve the above-mentioned problems of the prior art, and it is possible to achieve warm spinning forming with good surface properties by ensuring lubrication between the material to be formed and the roller. An object of the present invention is to provide a method for forming a magnesium alloy wheel for a vehicle, which can improve productivity and product quality.

[0008]

In order to achieve the above object, the present invention has the following constitution. That is, the method for forming a magnesium alloy wheel for a vehicle according to the present invention is a method in which a magnesium alloy material is die-forged into an intermediate material formed by substantially molding a rim portion and a disk portion, and then the rim portion of this intermediate material is formed by spinning. In a method of forming a magnesium alloy wheel for a vehicle that performs warm spinning forming into a predetermined wheel shape with a roller of a machine, while applying a solid lubricant to the rim portion of the intermediate material before warm spinning forming, It is characterized by performing warm spinning forming while continuously applying a solid lubricant to the roller surface.

[0009]

The solid lubricant does not react with the magnesium alloy material due to heat generation, and can be easily applied by adding an oily solvent to form a basal state. However, when a solid lubricant made into a basate state by adding an oily solvent is vaporized into a powder when heated, it becomes difficult to apply it evenly to the material surface during warm spinning molding. However, in the method of the present invention, since the solid lubricant is applied to the rim portion of the intermediate material before the warm spinning molding, that is, since it is applied cold, the application to the rim portion is uniform. Therefore, the initial lubrication between the rollers can be secured. In addition, solid lubricant,
Since warm spinning molding is performed while continuously applying to the roller surface, that is, since it is applied to the roller surface that can be lower in temperature than the intermediate material to be heated, the application to this roller surface is surely and evenly made, It is possible to secure lubrication with the intermediate material during the warm spinning forming.

Solid lubricants used in the present invention include molybdenum disulfide (MoS ₂ ), graphite and boron nitride (B
It is also preferable to add an oily solvent to fine particles such as N) to form a basate.

[0011]

Embodiments of the method of the present invention will be described below with reference to the drawings.

[0012] [Fig. 1] is a schematic explanatory view of a forming method of a magnesium alloy wheel of the present embodiment, wherein (a) is a front sectional view showing an intermediate material, and (b) is a diagram of warm spinning forming. FIG. 5 is a front sectional view showing a situation on the way, (c) is a front sectional view showing a situation at the end of the warm spinning forming, and (d) is a sectional view taken along the line AA of FIG.

In the present embodiment, first, a magnesium alloy material is die-forged to have an intermediate material having a disk portion Md formed into a final shape and a rim portion Mr roughly formed into a final shape as shown in FIG. Produce M. Then, prior to the warm spinning molding described below, a solid lubricant made into a basate by adding an oily solvent to molybdenum disulfide (MoS ₂ ) is formed on the entire surface of the roughly formed rim portion Mr of the intermediate material M. Apply evenly.

Next, as shown in FIG. 1B, the disk portions Md of these intermediate materials M are mounted on the driving and driven mandrels (2), (3) of the spinning molding machine (1) which face each other. The pair of dies (4) and (4 ') are clamped and rotated, and the rim portion Mr of the intermediate material M is paired with the dies (4) and (4').
While heating to a temperature of about 300 ° C by a heater (6) arranged on the side of the rim, the rim portion Mr of the roller (5) is used to surround the outer mold of the pair of molds (4), (4 '). Press it against the surface to handle it,
As shown in (c), warm spinning is performed into a predetermined wheel shape.

Further, in the present embodiment, as shown in (d), one side of the roller (5) is connected to a lubricant container (not shown) via a small pump to form a lubricant nozzle (7). The lubricant nozzle (7) was used to continuously apply the same type of solid lubricant as described above to the outer peripheral surface of the roller (5) during warm spinning. Also, on the other side of this roller (5),
A blower nozzle (8) connected to an air supply source (not shown) is placed, and the air is blown from this blower nozzle (8).
(5) was continuously cooled during the warm spinning forming.

Here, the lubricant nozzle (7) and the blowing nozzle (8) mean that the blowing nozzle (8) is located on the upstream side with respect to the rotation direction of the roller (5) and the lubricating nozzle is on the downstream side. Position (7) to face each other and add the solid lubricant,
The roller (5) can be applied at the site cooled by the blow nozzle (8).

As described above, in this embodiment of warm spinning forming, the lubrication between the magnesium alloy material to be formed and the lubricant is stably ensured without causing a reaction with heat generation. As a result, it is possible to perform spinning molding with a good surface quality, and therefore it is possible to achieve both stabilization of the quality of the magnesium alloy wheel to be molded and improvement of productivity.

In this embodiment, an external heating method is used in which the rim portion of the intermediate material is heated to a predetermined temperature by the heater arranged on the side of the mold, but this is only an example. The material to be molded may be heated by the internal heating method as in the above-described conventional technique, or may be used in combination.

[0019]

As described above, according to the method for forming a magnesium alloy wheel for a vehicle according to the present invention, the lubrication between the magnesium alloy material to be formed and the roller is ensured, and the warm surface having a good surface property is obtained. Spin molding can be performed, and stabilization of product quality and improvement of productivity can be achieved.

[Brief description of drawings]

1A and 1B are schematic explanatory views of a method for forming a magnesium alloy wheel according to an embodiment of the present invention, where FIG. 1A is a front sectional view showing an intermediate material, and FIG. 1B is a state in the middle of warm spinning forming. Is a front sectional view showing the state at the end of the warm spinning forming, and (d) is a sectional view taken along the line AA of (b).

FIG. 2 is a schematic explanatory view of a conventional method for forming a magnesium alloy wheel.

[Explanation of symbols]

 (1) --Spinning molding machine (2) --Drive mandrel (3) --Driven mandrel, (4) --Mold (4 ')-Mold (5) --Roller (6) --Heater (7) --Lubricant nozzle (8) --Blower nozzle M --Intermediate material Md --Disk portion Mr --Rim portion

Claims (1)

[Claims] 1. A magnesium alloy material is die-forged to form an intermediate material obtained by substantially molding a disk portion and a rim portion,
In the method of forming a magnesium alloy wheel for a vehicle in which the rim portion of this intermediate material is warm-spun formed into a predetermined wheel shape by the rollers of a spinning molding machine, a solid lubricant is applied to the rim portion of the intermediate material before the warm spinning forming. A method for forming a magnesium alloy wheel for a vehicle, which comprises performing warm spinning forming while continuously applying a solid lubricant to a roller surface of a spinning forming machine while applying.