JP5779913B2 - Spline molded body molding method and inner diameter spline tooth molding apparatus - Google Patents

Description

The present invention, molding how spline shaped body, and relates to the inner diameter spline teeth forming apparatus, and more particularly, to a technique for forming a spline shaped body having a boss portion.

  Conventionally, when molding a part having a flange portion or a boss portion from a plate material, a technique of performing burring after drawing processing on the plate material is generally used (see, for example, Patent Document 1 and Patent Document 2). .

JP 2004-34037 A JP 2009-78284 A

  In the prior art, as shown in FIG. 4, the inner hole is punched after drawing the plate member. Then, the periphery of the hole is raised by burring to form a boss portion, and a spline or the like is processed by plastic deformation on the inner peripheral surface of the boss portion.

  When heat treatment such as induction hardening is applied to the spline molded body formed as described above, the residual stress is released, and as shown by the arrow α in FIG. There is a case. When such deformation occurs, the accuracy of splines formed by plastic working deteriorates. In addition, it is difficult to form a spline by plastic deformation in consideration of such deformation in advance.

  On the other hand, in Patent Document 1, when the punch portion is inserted from the distal end of the boss portion to form a tooth, the deburring process is eliminated by pushing the distal end side of the boss portion toward the proximal end side by the punch portion. The technology is described. However, this technique is intended for deburring and cannot prevent deformation due to heat treatment.

  Therefore, in view of the above situation, the present invention provides a spline molded body molding method and spline molded body that can prevent deformation of the spline molded body even when residual stress is released when heat treatment such as induction hardening is performed. And an inner diameter spline tooth forming apparatus.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

  That is, according to the first aspect of the present invention, a forming step of forming a boss having an open end by burring, a spline is formed by plastically deforming the inner peripheral surface of the boss, and at the same time, the spline is A deformation step in which the inner diameter from the end of the spline to the tip is made larger than the inner diameter of the groove of the spline by plastically deforming the tip to reduce the plate thickness.

  According to a second aspect of the present invention, in the deformation step, the tip portion is plastically deformed so that the thickness of the tip portion is substantially uniform over the entire circumference.

  According to a third aspect of the present invention, in the molding step, the boss is erected and opened on a flat plate portion, and a concave portion is formed over the entire circumference on the outer peripheral surface side of the base portion of the boss.

In Claim 4, It is an internal diameter spline tooth-forming apparatus which inserts a punch part from the side of the above-mentioned tip part to the boss with which the tip part was opened, and forms a spline in the inner peripheral surface of the above-mentioned boss,
The punch portion includes a spline forming protrusion formed on the distal end side of the punch portion, and a convex portion having a larger outer diameter than the spline forming protrusion formed over the entire circumference on the proximal end side of the punch portion. With
By inserting the punch portion on the tip end side of the boss, the inner peripheral surface of the boss is plastically deformed to form a spline, and at the same time, from the end of the spline to the tip end is plastically deformed. By reducing the plate thickness, the inner diameter from the end of the spline to the tip is made larger than the inner diameter of the groove of the spline .

  As effects of the present invention, the following effects can be obtained.

  According to the present invention, even when residual stress is released when heat treatment such as induction hardening is performed, deformation of the spline molded body can be prevented.

Sectional drawing which showed the boss | hub formation method which concerns on 1st embodiment. The expanded sectional view which similarly showed the molded object by the boss | molding method. The expanded sectional view which showed the molded object by the boss | hub formation method which concerns on 2nd embodiment. Sectional drawing which showed the boss | hub formation method which concerns on a prior art.

Next, embodiments of the invention will be described.
It should be noted that the technical scope of the present invention is not limited to the following examples, but broadly covers the entire scope of the technical idea that the present invention truly intends, as will be apparent from the matters described in the present specification and drawings. It extends.

[First embodiment]
First, a boss forming method according to the first embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 1C, the boss forming method according to the present embodiment is used in an inner diameter spline tooth forming apparatus 10 that forms a spline Ws with respect to a work W that is a molding target.

  As shown in FIG. 1 (a), the workpiece W has a flat plate portion and a boss portion standing on the flat plate portion and having an open end Wt. Specifically, as in the prior art shown in FIGS. 4 (a) to 4 (c), after performing drawing processing on a molded body that is a plate material, inner hole punching processing is performed, and the periphery of the hole is raised by burring processing. A boss part is formed.

  The inner diameter spline tooth forming apparatus 10 includes an upper surface support portion 11, a lower surface support portion 12, and a punch portion 21. When the spline Ws is formed on the workpiece W, the flat plate portion of the workpiece W is sandwiched between the upper surface support portion 11 and the lower surface support portion 12 as shown in FIG. As shown in FIG. 2, the punch portion 21 is inserted from the tip portion Wt of the workpiece W. Then, the workpiece W is plastically processed by the spline forming projections 22, 22... Formed around the tip end side (upper side in FIG. 1) of the punch portion 21, so that the boss portion as shown in FIG. The spline Ws is formed on the inner peripheral surface of this.

  In addition, the punch portion 21 includes a convex portion 23 formed over the entire circumference on the proximal end side of the punch portion 21 and having a larger outer diameter than the spline forming protrusions 22. When the formation of the spline Ws is completed by inserting the punch portion 21 into the tip Wt of the workpiece W, as shown in FIG. It is plastically deformed to be uniform. Specifically, as shown in FIG. 2, the inner peripheral surface of the tip portion Wt is plastically deformed outward to widen the inner diameter of the tip portion Wt.

  That is, the molded body molded by the boss molding method according to the present embodiment is plastic so that a boss having an open front end Wt is formed by burring, and the thickness of the front end Wt is substantially uniform over the entire circumference. Deformed. Further, the inner peripheral surface of the tip portion Wt is plastically deformed, so that the inner diameter of the tip portion Wt is expanded.

  In the molded body molded by the boss molding method according to the present embodiment, when the heat treatment such as induction hardening is performed by the configuration as described above, at the tip portion Wt, during the molding process by the convex portion 23 of the punch portion 21. The residual stress of is released. As a result, as indicated by an arrow A in FIG. 2, a force is applied to return to the original shape (plate thickness) at the tip Wt. Even when such a force is applied, the deformation occurs at the tip Wt, so that the influence on the spline Ws can be reduced. That is, since the deformation of the portion where the spline Ws is formed can be suppressed to a small level, it is possible to prevent the processing accuracy of the spline Ws from deteriorating.

  Moreover, since the plate | board thickness of the front-end | tip part Wt is plastically deformed so that it may become substantially uniform over the perimeter, it can prevent that a boss | hub part deform | transforms locally. That is, since the amount of deformation due to plastic deformation is substantially uniform on the inner peripheral surface of the tip portion Wt that originally has a uniform plate thickness, the residual stress at the tip portion Wt is also substantially uniform. For this reason, the force generated to return to the original shape (plate thickness) at the tip portion Wt is also substantially uniform, so that the deformation amount at the tip portion Wt is substantially uniform, and local deformation of the boss portion can be prevented. .

Further, since the punch portion 21 deforms the inner peripheral surface of the boss portion of the workpiece W at the convex portion 23, the appearance of the workpiece W is not impaired. In addition, since the tip portion Wt can be deformed with the same equipment configuration as that of the conventional molding technique, an increase in cost can be suppressed without complicating the manufacturing process.
Thus, in the boss forming method according to the present embodiment, even if the residual stress is released when heat treatment such as induction hardening is performed, deformation of the formed body in the spline Ws can be prevented.

[Second Embodiment]
Next, a boss forming method according to the second embodiment of the present invention will be described with reference to FIG.
In the boss forming method according to the present embodiment, the spline Ws is formed on the workpiece W and, at the same time, a pressing force is applied from the lower surface support portion 12 to the root portion of the boss portion of the workpiece W, as in the embodiment. As shown in FIG. 3, a recess Wd is formed over the entire circumference on the outer peripheral surface side of the base portion of the boss portion of the workpiece W.
By configuring in this way, the concave portion Wd is work-hardened, so that even when the residual stress at the time of forming the boss portion is released by heat treatment, the boss portion can be prevented from being deformed inward and falling down.

DESCRIPTION OF SYMBOLS 10 Inner diameter spline tooth-forming apparatus 11 Upper surface support part 12 Lower surface support part 21 Punch part 22 Spline formation protrusion 23 Protrusion part W Work Ws Spline Wt Tip part

Claims (4)

A molding process for molding a boss whose tip is opened by burring,
The spline is formed by plastically deforming the inner peripheral surface of the boss, and at the same time, the plate thickness is reduced by plastically deforming from the end of the spline to the tip, thereby reducing the plate thickness from the end of the spline to the tip. A deforming step of making the inner diameter of the spline larger than the inner diameter of the groove portion of the spline,
A method for forming a spline molded body. In the deformation step, the tip portion is plastically deformed so that the thickness of the tip portion is substantially uniform over the entire circumference.
The method for forming a spline molded body according to claim 1, wherein: In the molding step, the boss is erected on the flat plate portion and opened, and a recess is formed over the entire circumference on the outer peripheral surface side of the base portion of the boss.
The method for forming a spline molded body according to claim 1 or 2, characterized by the above. It is an inner diameter spline tooth forming device that inserts a punch portion from the tip portion side with respect to the boss whose tip portion is opened, and forms a spline on the inner peripheral surface of the boss,
The punch portion includes a spline forming protrusion formed on the distal end side of the punch portion, and a convex portion having a larger outer diameter than the spline forming protrusion formed over the entire circumference on the proximal end side of the punch portion. With
By inserting the punch portion on the tip end side of the boss, the inner peripheral surface of the boss is plastically deformed to form a spline, and at the same time, from the end of the spline to the tip end is plastically deformed. By reducing the plate thickness, the inner diameter from the end of the spline to the tip is made larger than the inner diameter of the groove of the spline.
An internal diameter spline tooth forming apparatus.

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