JPH0233968Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a forming device for helical gears in a die-casting machine.

[Conventional technology]

In a molding device that uses an extrusion pin to extrude a helical gear material shape product, simply extruding the extrusion pin linearly may cause damage to the mold or galling or chipping of the teeth of the molded product. There are problems that arise.

In a conventional female thread forming device, an ultrasonic oscillator is used at the rear end of a spindle that has a threaded core formed at its tip and is attached to a through hole in a mold so that it can move back and forth using a feed screw linear movement mechanism and its rotational drive device. A device in which a controlled vibrator and a horn are integrally attached is disclosed in Japanese Utility Model Publication No. 14724/1983.

However, the above-mentioned device cannot be used to mold helical gears having teeth on the outer peripheral surface.

[Problem that the invention attempts to solve]

Therefore, as a result of studies in view of the above problems, the present invention was developed by using a helical gear guide provided in the through hole of the movable die to correspond to the helical gear of the product.
In addition, the extrusion pin, which is attached to move forward and backward, is provided with a fitting part at the tip of the extrusion pin, which allows the product to be rotated and extruded, resulting in an extremely simple configuration.
The purpose is to make it possible to extrude the helical gear smoothly without causing damage to the mold or the teeth of the molded helical gear.

[Means for solving problems]

That is, in the present invention, an extrusion pin is inserted into a through hole provided coaxially with the helical gear forming recess of a movable die, and is rotated by meshing with a helical gear guide provided corresponding to the helical gear of the product. In addition to being attached so that it can move forward and backward, the rear end is rotatably supported by a pin plate via a thrust bearing, and the tip of the extrusion pin is provided with a fitting part with the product so that the product can be rotated and extruded. , the above problems were solved.

〔Example〕

An embodiment of the present invention will be described below in detail based on the drawings. As shown in FIGS. 1 to 4 A and B, the fixed die 1 and the movable die 2 are integrated with each holder. However, it may be embedded and fixed in each of the illustrated fixed holder and movable holder.

A cavity 6 is formed coaxially between the fixed die 1 and the movable die 2, with recesses 4 and 5 facing each other for forming the helical gear product 3. A core 7 protrudes from the center of the recess 4 and is fixed by a set screw 8. On the other hand, the movable die 2 is provided with a through hole 9 coaxially with the recess 5, and the core 7 is fixed to the center of the recess 4. Dice 1
On the other hand, the movable die 2 is clamped and opened from the parting line in the direction of the arrow a←→a' shown in the figure.

A tooth forming part 5a for forming the tooth part 3a of the product 3 is provided on the inner circumferential surface of the recess 5 in the movable die 2.

A helical gear guide 12 is fixed to the rear end surface of the movable die 2 with a screw 10, and the inner circumferential surface of a hole 13 passing coaxially with the through hole 9 is fixed to the helical gear guide 12 with a screw 10. Helical teeth 14 are provided at the same twist angle and the same pitch in correspondence with the tooth portion 3a of the product 3, and are provided in the through hole 9 of the movable die 2 and the hole 13 of the helical gear guide 12. is product 1
An extrusion pin 15 for extruding 3 from the recess 5 is inserted.

Also in the middle of the extrusion pin 15, helical teeth 16 are provided around the same helical angle and the same pitch in correspondence with the tooth portion 3a, and the helical teeth 16 and the helical gear guide 12 are connected to each other. The helical teeth 14 are engaged with each other, and the push-out pin 15 is moved forward and backward in the axial direction, thereby forming the tooth portion 3a formed into the product 3.
A rotational force is applied corresponding to the twist angle.

Further, the rear end of the extrusion pin 15 is an enlarged head 15a.
It is rotatably supported by a pin plate 17 via a thrust bearing 18 in a state where axial movement is prevented, and hydraulic pressure (not shown) is provided on the pin plate 17 via a pull-back rod 20 fixed to the pin plate 17 with a screw 19. It is provided to be moved forward and backward by a cylinder.

More specifically, the pin plate 17 is the front pin plate 17.
A and the rear pin plate 17b are superimposed and fixed with screws, so the front pin plate 17a has a small diameter hole 21 and a large diameter hole 22 coaxially connected, and the small diameter hole 21 Insert the extrusion pin 15 into the enlarged head 15a.
is placed inside the large-diameter hole 22, and an annular step portion 23 and an enlarged head portion 15 are provided around the boundary between the two holes 21 and 22.
Since the push-out pin 15 is prevented from coming off in the axial direction by contacting the push-out pin 15, a washer 24 is interposed between the stepped portion 23 and the enlarged head 15a so that the push-out pin 15 can rotate smoothly. At the same time, the thrust bearing 18 is interposed between the enlarged head 15a and the rear pin plate 17b.

Further, the extrusion pin 15 is provided with a fitting part 25 on the distal end surface of the product 3 so that the product 3 can be fitted into the product 3 and the product 3 can be rotated and extruded.

The fitting portion 25 has a concave groove 25a which is long in the diametrical direction of the push-out pin 15, as shown by solid lines in FIG.
It may be provided on a diametrically long protrusion 25b, as shown by the two-dot broken line in the same figure.
Furthermore, in the cross-shaped recess or convex part, furthermore,
It can be formed into any polygonal, elliptical, etc. concave or convex portion, and in any shape, the product can be rotated around the axis by the extrusion pin 15, and the product 3 is provided so that it can be pulled out in the axial direction.

In the above-mentioned configuration, in the mold clamping state shown in FIG.
The product 3 is molded in a state where it fits into the fitting portion 25 of No. 5.

After molding the product, the mold is opened in the direction of arrow b as shown in FIG.
When the push-out pin 15 supported by the pin plate 17 is pushed forward in the left direction in the figure, the push-out pin 15 is pushed forward, but at this time, the helical teeth 1 of the pin 15
6 and the helical teeth 14 of the helical gear guide 12 are in mesh with each other, a rotational force is applied to the ejector pin 15, whereby the ejector pin 15 corresponds to the tooth portion 3a of the product 3. The product 3 moves forward while rotating, extruding the product 3 from the recess 5 of the movable die 2 as shown in FIG.

Figure 5 shows a molded helical gear.
When the fitting portion 25 is formed into a long groove 25a, a protrusion 3b corresponding to the groove 25a is formed on the rear end of the helical gear product 3 as shown in the figure. The protrusions 3b may be processed by post-processing.

[Effect of idea]

As explained above, since the helical gear molding device according to the present invention is configured, after opening the mold,
When the ejecting pin 15 is driven forward, the ejecting pin 15 is moved forward by the helical teeth 14 of the helical gear guide 12 provided on the movable die 2 in correspondence with the helical teeth 3a of the product 3. The product 3 moves forward while rotating at the same rotation angle as the twist angle of the teeth 3a, and the fitting part 25 at the tip extrudes the product 3 while rotating in accordance with the twist angle of the teeth 3a. The helical gear can be extruded smoothly, the mold or the tooth portion 3a of the product 3 will not be damaged, and a highly accurate helical gear can be molded, and the durability of the molding device can also be improved.

Further, the fitting portion 25 of the extrusion pin 15 with the product 3 can be formed by a groove, a protrusion, etc. of any shape, so it is extremely simple in structure and can be implemented at low cost.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional side view showing an embodiment of the helical gear forming apparatus according to the present invention in a mold closed state, Fig. 2 is a longitudinal sectional side view showing the same embodiment in a mold open state, and Fig. 3 4A and 4B are front views and longitudinal side views illustrating the fitting portion of the extrusion pin in the same embodiment, and FIGS.
The figure is a side view of a helical gear molded in the same example. 2... Movable die, 5... Helical gear molding recess, 9... Through hole, 12... Helical gear guide,
15... Extrusion pin, 17... Pin plate, 18... Thrust bearing, 25... Fitting portion.

Claims (1)

[Scope of utility model registration request] The extrusion pin 15 is inserted into the through hole 9 provided coaxially with the helical gear forming recess 5 of the movable die 2, and is rotated by meshing with the helical gear guide 12 provided corresponding to the helical gear of the product. It is attached so that it can move forward and backward, and the rear end is rotatably supported by a thrust bearing 18 on a pin plate 17, and a fitting part 25 with the product is provided at the tip of the extrusion pin so that the product can be rotated and extruded. A helical gear forming device characterized by: