JP3029991B2 - Rolling method of inner spline - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for rolling an inner spline. More specifically, the present invention relates to a method for rolling an inner spline of a cylindrical member having a spline formed on an inner periphery thereof, in which a round portion is not formed inside a connection portion between a bottom portion and a peripheral wall portion.

[0002]

2. Description of the Related Art Conventionally, a product having a spline or teeth formed on an inner peripheral surface of a cylindrical member has been manufactured by machining a forged product. However, machining from a forged product is difficult, and the thickness of the cylindrical portion needs to be 4 to 6 mm. For this reason, recently, a rolling method has been used to reduce the thickness, weight, and ease of processing.

[0003] As a rolling method for forming a spline on the inner periphery of a cylindrical member, Japanese Patent Application Laid-Open Nos. 6-23461, 5-23774, 4-327.
No. 333 is known. FIG. 5 is a view showing the working principle. The work material 3 is sandwiched between a mandrel 1 having a spline 1a formed on its surface and a holder 2, and the work material 3 is rotated by a forming roller 4 while rotating.
Is pressed against the spline 1a of the mandrel 1 to obtain a cylindrical member having the spline transferred to the inner surface.

[0004] As a product in which a sub-line is formed on the inner periphery of such a cylindrical member, there is a housing of a viscous coupling which constitutes a part of a transmission of a vehicle. This viscous coupling is a kind of viscous clutch that transmits torque by using the shear resistance of a viscous fluid, and its structure is composed of a plate fixed to an outer case (housing) and a plate fixed to an inner shaft. They are arranged alternately one by one, and filled with silicone oil, which is a viscous fluid.

[0005] Then, the case and the shaft rotate together and transmit torque when slippage occurs between them. The magnitude of the torque changes according to the rotational speed difference, that is, the speed at which the plate shears the silicon oil, and as the rotational speed difference increases from the point where the rotational speed difference is zero, the torque draws a smooth curve and increases. .

[0006]

In the case where the housing of the above-mentioned viscous coupling is formed by the above-mentioned conventional inner spline rolling method, as shown in FIG. 6, the peripheral wall 5a and the bottom 5b of the housing 5 are formed. A little R is formed at the connecting portion with the. For this reason, there is a problem that the plate 7 of the viscous coupling floats as shown in FIG.

It is also conceivable to reduce the diameter of the plate 7 'so as not to run on the rounded portion as shown by the dashed line in FIG. 1, but in this case, the overlapping area between the plates is reduced, and the transmission is reduced. There is a problem that the torque is reduced.

The present invention has been made in view of the above-mentioned conventional problems, and has as its object to realize a method of rolling an inner spline in which a radius is not generated at a connecting portion between a peripheral wall portion and a bottom portion of a housing.

[0009]

SUMMARY OF THE INVENTION According to the present invention, there is provided a method for rolling an inner spline according to the present invention. The method includes a primary process of forming a workpiece into a bottomed cylindrical shape by drawing and a secondary process of forming an inner spline by rolling. In the method for rolling an inner spline, the connecting portion between the bottom and the peripheral wall of the workpiece to be formed into a cylindrical shape with a bottom during the drawing is expanded downward.
It is characterized in that it is formed so that the inside angle is an acute angle .

[0010] By adopting this configuration, it is possible to obtain a method of rolling an inner spline in which a round portion is not formed inside the connection portion between the peripheral wall portion and the bottom portion of the housing.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a view showing a workpiece used in a method for rolling an inner spline according to an embodiment of the present invention. The workpiece 10 is drawn into a cylinder with a bottom. The connecting portion between the peripheral wall 10a and the bottom 10b is expanded downward as shown in the figure, and the angle θ between the peripheral wall 10a and the bottom 10b is an acute angle. It is formed so that it becomes.

FIG. 2 shows an inner spline forming apparatus used in a method for rolling an inner spline according to an embodiment of the present invention. The apparatus comprises a lower mold 12 attached to a lower mold base 11 rotatable about a vertical center axis, and an upper mold 14 attached to an upper mold table 13 rotatable about the same central axis as the lower mold.
And a forming roller 15 having a central axis parallel to the central axes of the upper die and the lower die, and the central axis is movable.

The lower die 12 has a center pin 16 so as to position and support the workpiece 10 formed by a two-dot chain line and formed in a cylindrical shape with a bottom. The height of the portion of the workpiece 10 to which the bulging portion on the outer periphery of the bottom portion contacts is lower than the inner peripheral portion as shown in the enlarged view of FIG.

The upper die 14 has an upper die ring 17 capable of clamping an end of a peripheral wall of the workpiece 10, and an inner periphery of the upper die 17 slidable up and down and having a predetermined outer peripheral portion. Pad 1 having a spline 18a formed thereon
8 and a center wiping pin 19 slidable up and down on the inner periphery of the pad 18. The upper die ring 17 is fixed to the upper die base 13 with bolts 20. Guided and urged downward by a spring 22, the center wiping pin 19 is guided by a guide pin 23 and urged downward by springs 24 and 25.

The forming roller 15 has a disk shape having a thickness corresponding to the length of a spline formed on the workpiece 10 and is rotatably supported by a drive mechanism (not shown) in the center axis direction of the upper and lower dies. The workpiece 10 is advanced or retracted, and can press the peripheral wall of the workpiece 10 supported by the upper and lower dies.

The inner spline forming method of the present invention using the inner spline forming apparatus having such a configuration will be described with reference to FIGS. First, as shown in FIG. 3, a workpiece 10 previously formed in a cylindrical shape with a bottom is set in a lower mold 12, and the upper mold 14 is lowered to be clamped by a pad 18 and a center removing pin 19. Further upper mold 14
Is lowered, and the peripheral wall end surface of the workpiece 10 is pressed by the concave portion of the upper die ring 17.

Next, as shown in FIG. 4, the forming roller 15 is advanced by a drive mechanism (not shown) while the lower mold 12 and the upper mold 14 supporting the work 10 are rotated by a main shaft (not shown). The peripheral wall is pressed against the pad 18.

As a result, the workpiece 10 is pressed on the upper, lower, and side surfaces, and the splines 18a of the pads 18 are transferred to form inner splines. In this case, as shown in the enlarged view (b), the connecting portion between the peripheral wall portion 10a and the bottom portion 10b of the workpiece 10 is crushed by the forming roller 15 to form an acute angle, so that there is no round portion inside.

Next, the finished product on which the inner splines are formed is moved back by the forming roller 15, then the rotation of the main shaft is stopped, and the upper die 14 is further raised, so that the upper die ring 17 is formed by the springs 22, 24 and 25. And pad 1
8 can be taken out.

As described above, according to the present embodiment, the connecting portion between the peripheral wall and the bottom of the workpiece to be drawn into a cylindrical shape with the bottom is formed to have an acute angle in advance. Accordingly, when the inner spline is rolled, the portion is crushed and becomes an acute angle, so that the round portion is not formed inside.

[0021]

According to the inside spline rolling method of the present invention, the connecting portion between the peripheral wall portion and the bottom portion is formed at an acute angle so that no round portion is formed inside the connecting portion, and therefore, the conventional spline rolling method is not used. Thus, the plate of the housing of the viscous coupling is prevented from riding on the round portion, and a reduction in power transmission efficiency can be prevented.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a workpiece used in a method for rolling an inner spline according to an embodiment of the present invention.

FIG. 2 is a diagram showing a spline forming apparatus used in a method for rolling an inner spline according to an embodiment of the present invention, and (a).
2 is an entire cross-sectional view, and FIG. 2B is an enlarged view of a portion B in FIG.

FIG. 3 is a diagram for explaining a method of rolling the inside spline according to the embodiment of the present invention.

4A and 4B are diagrams for explaining a method of rolling the inside spline according to the embodiment of the present invention, wherein FIG.
FIG. 2B is an enlarged view of a portion B in FIG.

FIG. 5 is a view for explaining a conventional inner spline rolling method.

FIG. 6 is a diagram for explaining a problem to be solved by the invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Workpiece material 11 ... Lower mold stand 12 ... Lower mold 13 ... Upper mold stand 14 ... Upper mold 15 ... Forming roller 16 ... Center pin 17 ... Upper mold ring 18 ... Pad 19 ... Center removal pin 20 ... Bolt 21, 23 … Guide bins 22, 24, 25… Springs

Continuation of front page (56) References JP-A-62-263828 (JP, A) JP-A-5-23774 (JP, A) JP-A-6-23461 (JP, A) JP-A-5-76982 (JP JP-A-62-142040 (JP, A) JP-A-59-78737 (JP, A) JP-A-5-52249 (JP, A) JP-A-7-88582 (JP, A) (58) Field surveyed (Int.Cl. ⁷ , DB name) B21H 1/00-9/02 B21D 53/28 B21D 22/26-22/30 B21K 1/30

Claims (1)

(57) [Claims] 1. A method for rolling an inner spline, comprising: a primary processing of forming a workpiece into a cylindrical shape with a bottom by drawing and a secondary processing of forming an inner spline by rolling. The joint between the bottom and the peripheral wall of the workpiece, sometimes formed into a cylindrical shape with a bottom , is swelled downward and its inner corner
A method of rolling an inner spline, wherein the inner spline is formed to have an acute angle.