JPH0227055B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to press forging of metal having a protruding portion forming a recess in a workpiece on a part of the forming surface of a lower die;
The present invention relates to a knockout device used to take out a workpiece from a mold such as a die casting mold.

(Prior Art) As shown in FIG. 3, in the conventional lower die knockout device, a bar-shaped knockout pin 40 is slidably inserted into a hole 43 provided in a protruding portion 42 of the lower die. The workpiece indicated by A was pushed out by the end face 41 of 40.

(Problems to be Solved by the Invention) In the conventional knockout device, fine powder of metal scale may fall between the knockout pin 40 and the hole 43 and obstruct the movement of the knockout pin 40. Length l of the protruding part 42 of the mold
When the length of the workpiece A is long, the restraining force of the protruding portion on the workpiece A is large, making it difficult to extrude the workpiece A.

(Means for Solving the Problems) The present invention solves the above-mentioned problems using extremely simple means. The protruding portion is divided into a lower base portion and an upper head portion within the protrusion height range, and a knockout pin is slidably inserted into the base portion, and a knockout pin is inserted at the tip of the knockout pin. It is characterized in that the head is attached.

(Function) After the molding or casting operation, when the knockout pin 11 is pushed up together with the head 9, the workpiece A is knocked out. Since the protruding portion 7 of the lower mold is divided into a base portion 8 and a head portion 9, the restraint force on the workpiece is divided into two when knocking out the workpiece, and the workpiece can be easily knocked out.

(Example) Figures 1 and 2 show a mold in which the present invention is applied to hot bending and finish forming of a knuckle (work) of a front wheel of an automobile.
comprises a lower mold main body 2, a movable mold 4 that moves up and down in a space 3 in the main body 2, and an arm stand 5 fixed on the main body 2.

The movable mold 4 includes an outer cylinder 6 and a positioning core 7 that is mounted inside the outer cylinder 6 and forms a protruding part. There is. A pin 11 is slidably inserted into the hole 10 of the base 8, and a protrusion 13 of the head 9 fits into a hole 12 on the end face of the pin, and is fixed with a bolt 14. The movable mold 4 has a movable plate 16 fixed to its lower surface with bolts 15, and is driven up and down by a hydraulic cylinder 17.

18 is a slide balancer, its large diameter part 19
is fitted into the guide hole 20 of the lower die main body 2, and the small diameter part 2
1 fits into the guide hole 22 of the moving plate 16.
These fitting portions prevent the movable mold 4 from tilting, and the spring 23 supporting the lower end of the large diameter portion 19 cushions the shock received from the upper mold. Reference numeral 24 denotes a knockout pin, which is operated together with the knockout pin 11 by a knockout plate 25 and an extrusion rod 26.

The upper die 30 consists of an upper die body 31 and a bending cam 32, and a knockout pin 3 passes through the body 31.
3, 34, 35 are provided and these pins are operated by a knockout plate 36 and a push rod 37.

Next, the function of this mold will be explained. The upper mold 1 is raised, the hydraulic cylinder 17 is actuated to raise the movable plate 16 to the upper end of the space 3, the movable mold 4 is brought to the same height as the arm stand 5, and a straight knuckle heated to approximately 800°C is raised. When the center boss part of A is clamped between the movable mold 4 and the protrusion 38 of the upper mold, and the upper mold 1 and the movable mold 4 are lowered, the arm A' of the nut A is received by the arm stand 5, so that the upper mold 1 The knuckle is then bent into the shape shown in the figure at the lowest position of the movable mold 4, and the entire knuckle is subjected to a finishing molding action according to the shape of the mold.

After molding, the upper and lower molds are separated, and the knockout pins 11, 24, 33, 34, and 35 are operated to separate the knuckle A from the molds. At this time, lower mold 1
The positioning core 7, which is a protruding part forming a part of the molding surface, is fitted into the recess of the nutcle A over a length l, but the core 7 is separated into a base 8 and a head 9. Therefore, the force required to separate the knuckle A from the core 7 is reduced by an amount corresponding to the height l' of the head 9, making it easy to separate it from the lower mold.
After the knuckle A is separated from the upper and lower molds, since the knuckle A is connected only to the head 9, it can be easily separated from there by applying a small external force.

Furthermore, the head 9 acts as a cover for the hole 10 of the base 8 and prevents fine powder of metal scale generated during the molding process from entering the gap between the hole 10 and the pin 11. Therefore, the movement of the pin 11 is not obstructed.

On the other hand, the knockout pin 4 shown in FIG.
In the conventional type in which the nut A is simply inserted into the hole 43 of the core 42, fine powder easily enters the gap, and furthermore, the fitting length l between the nut A and the core 42 is long, making it difficult to knock out. It has the following drawback.

(Effects of the Invention) Since fine powder of metal scale does not fall into the hole through which the knockout pin is inserted, the movement of the knockout pin is not obstructed. Furthermore, since the large protruding portion is divided into two parts, the base and the head, the restraining force on the workpiece is also divided into two parts when knocked out, making it easier to separate the workpiece.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a hot bending mold equipped with the knockout device of the present invention, FIG. 2 is a longitudinal sectional view of the main part of the present invention, and FIG. 3 is a longitudinal sectional view of a conventional device. 7...Protrusion part, 8...Base, 9...Head, 1
1...Knock out pin.

Claims (1)

[Claims] 1. In a mold having a protruding part that forms a recess in the workpiece on a part of the molding surface of the lower mold, the protruding part is divided into two into a lower base and an upper head within the protruding height range, A knockout device for a mold, characterized in that a knockout pin is slidably inserted into the base, and the head is attached to the tip of the knockout pin.