JPH0618668Y2 - Spline mold - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a spline forming die for forming a large number of tooth-shaped grooves on a cylindrical work, and more particularly to improvement of a punch shape for spline forming.

(Prior Art) Conventionally, there is a product in which a spline extending in the axial direction of the work is formed on the outer peripheral surface of a cylindrical work made of sheet metal such as a clutch drum as a power transmission system part of an automobile. As a molding die for molding such a spline, there is one as shown in Japanese Utility Model Laid-Open No. 53-93538. This is performed by pressing the outer peripheral surface of the work with a die and a punch, and as shown in FIG. 5, the spline 3 extends over the entire outer peripheral surface 2a of the work and leaves a predetermined dimension u from the lower end.
As a result, unevenness is formed. More specifically, as shown in FIG. 8, the inner peripheral surface of the cylindrical work a is brought into contact with a die b having a large number of concave portions c at equal intervals on the outer peripheral surface thereof to form the concave portion c of the die b. A punch d having a substantially matched tip shape is moved toward the center of the die b (arrow A in the figure).
Work direction a) and press work
Is to be plastically deformed into a shape along the die b.

(Problems to be Solved by the Invention) However, in the conventional spline molding die, the punch d has a portion S corresponding to the concave portion c of the die a for the work a.
Only press it. Therefore, the undeformed portion e is only in contact with the outer peripheral surface of the die b, which causes the following problems.

That is, as shown in FIG. 9, in the pressing step using the punch d, the ridge line portion between the tooth tip surface g and the tooth side surface h of the spline f to be formed is bent. Therefore, the unmolded portion, that is, the tooth tip surface g portion is likely to be bent outward in the radial direction of the work (direction of arrow B in the figure).
When such bending occurs, the radius of curvature of the ridge portion becomes large, so that the dimension t of the straight portion extending from the tooth bottom surface i of the tooth side surface h to the tooth crest surface g becomes short, and the spline f meshes. The meshability with other mating members deteriorates. Also,
Due to the bending, the outer diameter of the product becomes large, and therefore, the installation space for the product must be set in consideration of the increased size. In addition, variations in the spline tooth profile impair the homogeneity of the product, and further cause various problems such as deterioration of workability in the subsequent process such as drilling oil holes.

Then, this invention aims at obtaining a desired spline tooth profile by improving the shape of a punch.

(Means for Solving the Problem) In order to achieve the above object, the present invention adopts a punch shape that causes a meat flow in the pressing direction of the work. Specifically, for a spline molding die that forms a large number of tooth profile grooves extending in the central axis direction of the workpiece on the peripheral surface of a cylindrical sheet metal work, a cylindrical die having a recess for tooth profile groove formation on the outer periphery. And a punch disposed around the die so as to be able to come into contact with and separate from the die and press the work toward the die. The punch has a work spline tooth formed into a predetermined shape during the pressing. It is configured to have a pressing portion that causes the meat flow for the purpose.

(Operation) With the above configuration, in the present invention, the pressing portion of the punch presses the work during pressurization by the punch to cause meat flow, and the work spline teeth are formed into the predetermined shape. As a result, the shape of the work spline teeth can be formed into a desired shape along the die, and the reliability of the product is improved.

First Embodiment Next, a first embodiment of the present invention will be described with reference to the drawings.

FIG. 5 shows that the spline 3 is formed by forming a tooth-shaped groove 2e on the outer peripheral surface 2a by the spline molding die 1 according to this embodiment.
The clutch drum 2 in which is molded is shown. As can be seen from this figure, the clutch drum 2 is formed by forming the spline 3 over the entire outer peripheral surface 2a of the cylindrical metal work W and leaving a predetermined dimension u from the lower end 2c.

Next, the spline mold 1 will be described. The spline molding die 1 includes a die 4 and a large number of punches 5 arranged around the die 4 so as to be able to come into contact with and separate from the die 4. As shown in FIGS. 2 and 3, the die 4 has a columnar shape capable of being tightly fitted in the work W, and the outer peripheral surface 4a thereof has a toothed groove 2e during spline machining.
A large number of recesses 4b are formed in a trapezoidal cross section, which form the molding surface, at equal intervals with a predetermined dimension. That is, the outer periphery of the die 4 has an uneven shape that matches the shape of the spline 3 to be molded, and the side surface 4c of the recess 4b, that is, the portion forming the tooth side surface 3a of the spline 3 is a flat surface. It is said that.

On the other hand, the punch 5, which is a characteristic member of the present invention, is composed of a spline pressing portion 6 and a lower end molding portion 7 as shown in FIG. The spline pressing portion 6 has a tapered tip portion 6a which is similar to the shape of the concave portion 4b formed in the die 4, and during spline molding, the tip portion 6a is formed between the tip portion 6a and the concave portion 4b of the die 4. Then, the work W is pressurized and pressed. As shown in FIG. 1, the characteristic feature of the spline pressurizing section 6 is that it is provided on the inclined surfaces 6b located on the left and right of the tip section 6a.
It is on the pair of protrusions 8, 8. The protrusions 8 and 8 are formed in the vertical direction of the spline pressurizing portion 6 at a position slightly shifted from the base end portion 6c of the inclined surface 6b to the tip end side, and the outer periphery of the work W is formed at the time of spline molding. The surface 2a, in particular, the ridge portion between the tooth top surface 3b of the spline 3 and the tooth side surface 3a is brought into contact with and pressed.

On the other hand, the lower end molding portion 7 is integrally formed on one side in the vertical direction of the spline pressing portion 6, and as shown in FIG.
A width dimension corresponding to the circumferential direction of the work is formed to be longer than that of the spline pressing portion 6 by a dimension v to the left and right. This dimension is set so that when the punch 5 presses the work W, it does not interfere with the punch 5 adjacent to the punch 5. Further, the tip of the lower end molding portion 7 slightly protrudes from the spline pressure portion 6 toward the die side, and the tip 7a is a curved surface conforming to the shape of the outer peripheral surface of the work W. An inclined surface 7c facing the lower surface 7b is formed near the tip 7a.
The inclined surface 7c presses and forms the bent portion 3d near the lower end of the spline 3 during spline molding.

Next, the operation of the spline molding die 1 during spline molding will be described.

First, as shown in FIG. 2, a cylindrical work W is fitted onto the die 4, and the inner peripheral surface 2b of the work W is attached to the outer peripheral surface 4a of the die 4.
Abut. Then, in this state, one or a plurality of punches 5 are arranged corresponding to the concave portions 4b of the die 4, moved to the radial center side of the work W, and the work W is pressed. As a result, the work W is plastically deformed between the recess 4b of the die 4 and the tip 6a of the punch 5, whereby the spline 3 is formed on the outer peripheral surface 2a of the work W. This work is performed over the entire circumference of the work W.

The characteristic operation during the molding of the spline 3 is the action of the projection 8 formed on the tip portion 6a of the punch 5. That is, as shown in FIG. 1, at the final stage of the forming process of the spline 3 by the punch 5, the projection 8 locally presses the ridgeline portion between the tooth tip surface 3b and the tooth side surface 3a of the spline 3, A plastic flow occurs around the pressed part, and a part of this flowed material is
As shown by an arrow C in FIG. 1, the splines 3 flow toward the tooth bottom surface 3c side. Therefore, a sufficient amount of material is supplied to the tooth side surface 3a side of the spline 3, and this tooth side surface 3a
Is filled along the shape of the punch 5, and the recess 4 of the die 4
b and the shape of the tip 6a of the punch 5 are formed. As a result, the length of the straight line portion t'extending from the tooth bottom surface 3c toward the tooth crest surface 3b is formed to a desired length. In this case, the thickness of the portion of the work W pressed by the protrusion 8 is small, but the protrusion size of the protrusion 8 may be set so as not to hinder the strength of this portion.

Further, the tip end 7a of the lower end molding portion 7 is slightly projected from the tip end portion 6a of the spline pressurizing portion 6, and the inclined surface 7c is formed in a part thereof, as shown in FIG. In addition, the switching dimension x of the bent portion 3d around the lower end portion of the spline 3 can be made smaller than the dimension x'of the same portion (shown by a virtual line in the figure) of the related art, and the height of the product can be reduced. Is done.

As described above, according to the spline molding die 1 of the present example, the spline shape can be formed into a desired shape along the molding die, and in particular, the length of the straight portion of the spline tooth side surface 3a can be sufficiently increased. Ensuring increases product reliability and stability.

Second Example Next, a second example will be described.

As shown in FIG. 6, in the punch 5 of this example, the width dimension of the work W in the circumferential direction is made slightly longer than the first embodiment over the entire length of the punch 5 in the vertical direction. The end face shape of the elongated extension portion 9 conforms to the tip shape of the spline 3. The dimension of the extension portion 9 is set so that the adjacent punches 5 do not interfere with each other. Therefore, when the spline 3 is formed by the punch 5,
As shown in FIG. 7, the spline 3 is formed as in the first embodiment, and the extension portion 9 restricts the bending of the tooth top surface 3b of the spline 3 to obtain a desired tooth top surface shape. This means that the radius of curvature of the ridgeline portion between the tooth crest surface 3b and the tooth side surface 3a of the spline 3 becomes smaller, so that the straight portion of the tooth side surface 3a becomes longer.

Although the clutch drum is used as the product in this example, the present invention is not limited to this, and can be applied to those in which splines are formed on various cylindrical members.

(Effects of the Invention) As described above, according to the present invention, the work spline teeth can be formed into a desired shape along the die by fluidizing the work. Therefore, the straight portion extending from the tooth bottom surface of the tooth side of the spline to the tooth tip surface can be formed long, and the meshability with other members with which the spline meshes can be improved. Further, since the occurrence of bending on the tooth tip side unlike the conventional case is suppressed, the outer diameter dimension of the product does not become large, and the setting space of the product can be easily set.
Further, the product can be made uniform and the workability of the post-process can be improved, and the reliability of the product is improved.

[Brief description of drawings]

1 to 5 show a first embodiment of the present invention, FIG. 1 is a sectional view taken along the line I--I of FIG. 3, and FIG. 2 is a plan view showing a pressing operation by a spline forming die. 3 is a side view thereof, FIG. 4 is a sectional view taken along line IV-IV of FIG. 5, and FIG.
The figure is a perspective view in which the clutch drum is partially omitted. Sixth
7 and 8 show a second embodiment of the present invention, FIG. 6 is a plan view of a punch, and FIG. 7 is a plan view showing a pressing operation. 8 and 9 show a conventional example, and FIG. 8 shows a second example.
FIG. 9 is a view corresponding to FIG. 1, and FIG. 9 is a view corresponding to FIG. 1 ... Spline forming die 2e ... Tooth profile groove 4 ... Die 4b ... Recess 5 ... Punch 8 ... Protrusion (pressing part) 9 ... Extension part (pressing part) W ... Work

Claims (1)

[Scope of utility model registration request] 1. A spline molding die for forming a large number of tooth-shaped grooves extending in the central axis direction of the work on the peripheral surface of a cylindrical sheet-metal work, the cylinder having a recess for forming the tooth-shaped groove on the outer periphery. Equipped with a die and a punch disposed around the die so as to be able to come into contact with and separate from the die and press a work toward the die. The punch has a work spline tooth formed into a predetermined shape during the pressing. A spline molding die characterized in that it is provided with a pressing portion for causing meat flow to perform.