JPH10156465A - Formation of drive plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely form a drive plate which has a center flat part abutting on the end face of a crank shaft and an annular bead part externally fitted to the end part of the crank shaft only by press forming. SOLUTION: A based part 4' is formed by a rough forming process so that a vertical wall part 4'a of its inner peripheral side interferes with an inner peripheral side shoulder part of a protrusion 103a of a lower punch 103. An upper die 106 is divided into a first part 1061 to finish a flat face 3 and a second part 1062 to form the bead part 4, at beginning, the second part 1062 is approached to a punch 103 side to press the bead part 4', the vertical wall part 4'a is pushed in along an inner wall face of the protrusion 103a as well as the vertical wall part 4'a is deformed to a tapered shape while reducing its diameter upward. Next, the first part 1061 is approached to a punch 103 side to iron an inner peripheral face of the vertical wall part 4'a deformed to tapered shape, the bead part 4 and the flat part 3 are finished.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a drive plate for connecting a crankshaft of an engine to a power transmission member at an input end of a transmission.

[0002]

2. Description of the Related Art A drive plate has a central flat portion with an engine side being a rear side and a transmission side being a front side, and an annular bead formed by being recessed rearward around the flat portion. Then, the bead portion is fitted to the front end of the crankshaft to center the drive plate with respect to the crankshaft. In this state, the flat portion is brought into contact with the front end surface of the crankshaft, and the mounting hole formed in the flat portion is formed. The drive plate is bolted to the crankshaft.

Conventionally, when forming a drive plate, a blank is drawn into a required shape using a press die as shown in FIG. This press die includes a lower punch a having a flat surface a1 for forming a central flat portion of the drive plate from the front side (lower side in the drawing) and an annular projection a2 for forming a bead portion from the front side. And an upper die b having a flat surface b1 for forming a flat portion from the rear side (upper side in the drawing) and an annular concave groove b2 for forming a bead portion from the rear side. Flat part c1 '
FIG. 5 shows a blank c in which a bead c2 ′ and a bead c2 ′ are roughly formed.
As shown in FIG. 5 (A), it is set on the punch a, the die b is lowered, and the flat portion c1 is placed on the blank c as shown in FIG. 5 (B).
And the bead portion c2 are finish-molded. In this case, in the rough forming step, the bead portion c2 'is shaped so as not to interfere with the projection a2 of the punch a, that is, the bead portion c2'.
Is formed in such a shape that it goes over the protrusion a2 and the inner wall of the bead portion c2 ′ completely enters the space inside the protrusion a2.

[0004]

In the prior art described above, the squeeze round portion c3 'of the inner peripheral standing wall portion of the roughly formed bead portion c2' moves inward with the ironing of the inner peripheral standing wall portion by the die b. The pressed round part c3 remains on the flat part c1 that has been pressed and finished and forms undulation on the flat part c1. For this reason, conventionally, cutting is performed by machining to a position indicated by a two-dot chain line in FIG. 5B to secure the surface accuracy of the flat portion c1.
As a result, the number of steps is increased and the processing cost is increased.

SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to provide a method of forming a drive plate capable of ensuring surface accuracy of a flat portion without performing machining.

[0006]

Means for Solving the Problems In order to solve the above problems,
The present invention relates to a drive plate that connects a crankshaft of an engine and a power transmission member at an input end of a transmission, wherein a center of the drive plate is in contact with a front end surface of the crankshaft, with the engine side being the rear and the transmission side being the front. In a method of forming a flat portion and an annular bead portion which is fitted to the front end portion of a crankshaft and is formed by being recessed rearward around the flat portion, the flat portion and the bead portion are roughened on a blank. A molding step, a punch having a flat surface for molding the flat portion from the front side and an annular projection for molding the bead portion from the front side, and a flat surface and a bead portion for molding the flat portion from the rear side. Using a die having an annular concave groove to be molded, and a step of finish-molding a flat portion and a bead portion in the blank, and forming the bead portion in the rough molding step, and an upright wall portion on the inner peripheral side of the bead portion. Molding shaped to interfere with the shoulder portion of the inner peripheral side of the projection of the punch, characterized in that.

According to the present invention, when the die is brought close to the punch for finish molding, the inner wall on the inner peripheral side of the bead portion, which has interfered with the projection of the punch, is squeezed by the projection. Is pushed along. Then, a turning force in the direction of erecting the standing wall portion is applied to the standing wall portion by the ironing, and the turning radius portion of the standing wall portion is pulled outward by the rotating force, so that the pressing round portion is prevented from being pushed into the flat portion side. You. In this way, no drawing radius portion remains on the flat portion, and machining for ensuring surface accuracy of the flat portion is not required, so that the number of steps can be reduced and cost can be reduced.

Further, the die has a first portion having an end surface serving as the flat surface of the die and a peripheral surface serving as an inner peripheral surface of the groove, and a groove portion other than the inner peripheral surface of the groove. The first portion is divided into at least two portions with the second portion, the first portion is relatively movable with respect to the second portion, and the first portion is moved closer to the punch after the second portion is moved closer to the punch. For example, the pressurization of the bead portion by the second portion deforms the inner peripheral side wall portion of the bead portion into a tapered shape whose diameter decreases rearward,
Pushing of the throttle radius portion located on the front end side of the upright wall portion toward the flat portion side is more effectively prevented. Further, the inner peripheral surface of the upright wall portion deformed into the tapered shape as described above is squeezed by the first portion, so that the formability by the squeezing is improved, and the diameter accuracy of the inner peripheral surface of the upright wall portion is improved. At the same time, the effective fitting length to the crankshaft can be sufficiently ensured.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to molding of a drive plate 1 shown in FIG. 1 will be described. The drive plate 1 is a crankshaft A
And a fluid torque converter B, which is a power transmission member provided at an input end of the transmission, and has a disk portion 2 recessed in a dish-like shape with the engine side being the rear and the transmission side being the front. ing. The disk portion 2 is formed with a central flat portion 3, an annular bead portion 4 recessed rearward around the flat portion 3, and a flat portion 5 on the outer periphery. And
The upright wall portion 4a on the inner peripheral side of the bead portion 4 is
And the drive plate 1 is centered with respect to the crankshaft A. In this state, the central flat portion 3
Is brought into contact with the front end face of the crankshaft A, the flat portion 3 is bolted to the crankshaft A at a plurality of mounting holes 3a drilled therein, and the outer flat portion 5 is formed on the crankshaft A. Is bolted to the fluid torque converter B at the mounting hole 5a.

The disk portion 2 is further provided with a center hole 6 and a damping hole 7 for absorbing engine vibration, and a ring gear 8 is formed on the outermost periphery of the drive plate 1.
Are integrally formed, and a starter pinion C which enters from the front when the engine is started is meshed with the ring gear 8.

When the drive plate 1 is formed, a center hole 6 is formed in a circular blank 1 'as shown in FIG.
′ Is drawn backward in a bowl shape as shown in FIG. 2 (B) (first draw step), and then in the second, third and fourth draw steps shown in FIGS. 2 (C), (D) and (E). The blank 1 'is sequentially drawn and formed, and the portion of the disk portion 2 excluding the central flat portion 3 and the bead portion 4 is finish-formed. In the fifth drawing step, the central flat portion 3 is formed as shown in FIG. And the bead portion 4 are finish-molded. The first draw step is performed to prevent sinking due to reverse drawing in the subsequent draw step.

When the fifth draw step is completed, the outer periphery of the blank 1 'is trimmed and the mounting holes 3a and
Drilling of 5a and damping hole 7 is performed, and then blank 1 '
As shown in FIG. 2 (H), a flange 8 'which is folded back is formed on the outer peripheral edge of FIG.
The ring gear 8 is formed as shown in (I).

The fifth draw step is performed using a press die shown in FIG. The press die includes a lower die 100 and an upper die 102 that moves up and down while being guided by a post 101 erected on the lower die 100.

The lower mold 100 has a flat surface 1 for forming a central flat portion 3 of the drive plate 1 from the front side (lower side).
Punch 1 having an annular projection 103b for forming bead portion 4 from the front side, and a receiving surface 103c for receiving a portion of disk portion 2 which has been finished and formed in the fourth draw step.
The blank holder 104 is provided on the outer periphery of the punch 103 so that the blank holder 104 can be raised to a position regulated by the stopper pin 104b by the cushion cylinder 104a. The punch 103 is divided into a first portion 103 ₁ having a flat surface 103a, a second portion 103 ₂ having a projection 103b, and a third portion 103 ₃ having a receiving surface 103c.
The lower mold 100 is fixed to the lower mold 100 via the lower mold 05. It is also possible to integrate these portions 103 _1, 103 _2, 103 _3.

The upper mold 102 has a flat surface 106a for forming the central flat portion 3 from the rear side (upper side), and a bead portion 4
Annular groove 106b formed from the rear side, and a disk pressing surface 1 for pressing the portion of the disk portion 2 which has been finished formed.
A die 106 having a blank 06c and a blank pressing surface 106d for pressing an outer peripheral portion of the blank 1 'is provided.
The die 106 has an end surface which becomes a flat surface 106 a and a concave groove 106.
a first portion 106 ₁ having a peripheral surface serving as an inner peripheral surface of b;
A second portion 106 ₂ having grooves portions other than the inner circumferential surface of the recessed groove 106b, and third portion 106 ₃ forming the disk pressing surface 106c, first to form a blank pressing surface 106d 4
It is divided into a portion 106 _4. And the first part 1
06 ₁ via the backing plate 107
It is fixed to the fourth portion 106 ₄ die holder 10
8 to the upper mold 102, while the second part 106
₂ and the third portion 106 ₃ are attached to the upper mold 102 by a biasing member 109.
a backing plate 109 urged downward by a
It is fixed to.

In the fifth draw step, the outer peripheral portion of the blank 1 ′ formed in the fourth draw step is attached to the blank holder 104.
It is placed on the top, and the upper mold 102 is lowered in this state. The bead portion 4 'roughly formed in the fourth drawing step has a shape such that the inner peripheral side wall portion 4'a interferes with the inner peripheral side shoulder portion of the projection 103b as shown in FIG. 4A. Has become.

[0017] lowering the upper mold 102, first, by being pushed by the second portion 106 _second die 106 is urged downward by the urging member 109a, as shown in FIG. 4 (B), the vertical wall 4 'A is being squeezed by the protrusion 103b
b is pushed along the inner peripheral surface. Also, at this stage, the inner peripheral surface of the standing wall portion 4 ′ a is the first portion 10 of the die 106.
Since 6 ₁ unrestrained upright wall portion in the second portion 106 ₂ of the pressure 4'a is deformed into a tapered shape whose diameter decreases upward against the bead portion 4 '. And the projection 103
b into the inner peripheral surface and the upright wall portion 4'a by the deformation force.
To the upright wall portion 4 '.
Is drawn outward in the drawing radius portion R at the lower end of. Next, as the urging member 109a is compressed, the first portion 1
06 ₁ descends relative to the second portion 106 ₂ , FIG.
(C), the with the overall bead portion 4 including a vertical wall portion 4a is finished molded by squeezing the inner circumferential surface of the first portion 106 _1, the flat portion 3 is finish forming. On this occasion,
Since the drawn radius portion R is pulled outward as described above, the drawn radius portion R is not pushed into the flat portion 3 side, and the surface accuracy of the flat portion 3 is ensured only by press molding. Moreover, since squeezing the wall part 4'a which is deformed in a tapered shape with a first portion 106 _1, and improved moldability by ironing, the diameter accuracy of the upright wall portion 4a is improved, the vertical wall 4a
Is also sufficiently secured.

Therefore, it is not necessary to cut the inner peripheral surfaces of the flat portion 3 and the upright wall portion 4a by lace processing or the like in a later step to secure surface accuracy, diameter accuracy and effective length, thereby greatly reducing the processing cost. it can.

In the above embodiment, the die 106 is connected to the first
Or divided into fourth 4 parts 106 ₁ to 106 _4, it is possible to integrate them. However, in order to ensure diameter accuracy and the effective length of the vertical wall 4a is at least a first portion 106 ₁ is divided from other parts of the die 106, than the other portions as _a first portion 106 above It is desirable to delay and approach the punch 103 side.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of use of a drive plate.

FIGS. 2A to 2I are views showing a method for forming a drive plate according to the present invention.

FIG. 3 is a sectional view showing a press die used in the step of FIG. 2 (F).

4A, 4B, and 4C are diagrams showing a procedure for forming a flat portion and a bead portion by the press die shown in FIG. 3;

5 (A) and 5 (B) are views showing a conventional forming procedure of a flat portion and a bead portion.

[Explanation of symbols]

A crankshaft B hydrodynamic torque converter (power transmitting member) 1 drive plate 3 central flat portion 4 bead portion 4a standing wall portion 103 punch 103a flat surface 103b projection 106 die 106a flat surface 106b recessed groove 106 ₁ first portion 106 of the die ₂ The second part of the die

Claims (2)

[Claims] 1. A drive plate for connecting a crankshaft of an engine and a power transmission member at an input end of a transmission, wherein a center is in contact with a front end surface of the crankshaft, with an engine side being a rear side and a transmission side being a front side. A flat portion and an annular bead portion which is fitted to the front end portion of the crankshaft and is formed by recessing rearward around the flat portion, wherein the flat portion and the bead portion are formed on the blank. Rough forming step, a punch having a flat surface for forming a flat portion from the front side and an annular projection for forming a bead portion from the front side, and a flat surface and a bead portion for forming the flat portion from the back side. Finishing the flat portion and the bead portion on the blank by using a die having an annular concave groove formed from the die, and forming the bead portion in the rough forming process on the inner peripheral side of the bead portion. A method for forming a drive plate, wherein the wall is formed into a shape such that the wall interferes with a shoulder on the inner peripheral side of the projection of the punch. 2. The method according to claim 1, wherein the die includes a first portion having an end surface serving as the flat surface of the die and a peripheral surface serving as an inner peripheral surface of the groove.
The groove was divided into at least two parts, a second part having a groove part other than the inner peripheral surface of the concave groove, and the first part was made movable relative to the second part, and the second part was moved closer to the punch. 2. The method according to claim 1, wherein the first portion is moved closer to the punch.