JPS5813430A - Forging die for part having groove of reverse gradient - Google Patents

Abstract

PURPOSE:To form grooves of reverse gradient on inner face of a recessed part of a material and improve dimensional accuray by fitting one insert of a pair of inserts to an inner face of the recessed part of the material and ironing the outer peripheral face of the material by another insert. CONSTITUTION:The tip of a lock pin 11 is set at the inside of inserts 7 disposed radially. A preparatively formed material 1' is placed on it and grooves 2a are fitted to the inserts 7. Then, an upper die is lowered. Since projected parts 5 are positioned at the middle of adjoining inserts 7 in the upper die 3, the projected parts 5 iron the middle part of adjoining grooves 2a of the material 1 when the upper die 3 is lowered. Reverse gradient is formed in the lower part of the grooves 2a, and at the same time, inner peripheral face is formed to a curved face that fits to a spherical face. When the lock pin 11 is lowered, the inserts 7 are moved by elastic force of a spring 10 in centripetal direction and come off from the grooves 2. Then, the upper die 3 is raised, worked forged parts 1 are taken out from the inserts 7.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a forging die for parts having grooves of opposite slope on the inner circumferential surface.

For example, in a forged part such as an outer race of a constant velocity joint for an automobile, the inner peripheral surface of the four parts 1a is curved to fit a spherical surface, as shown in FIGS. It has a shape having a plurality of grooves 2.

When manufacturing a forged part 1 having such a groove 2 along the inner circumferential surface, that is, a groove 2 having an opposite slope to the forging direction, conventionally, as shown in FIG. In other words, a raw material 1' is made that has a straight shape below the P-P line in the drawing and has a groove 2a of a predetermined shape on the inner peripheral surface, and the tip of this material, that is, the outer periphery of the part ahead of the P-P line, is struck, or The groove 2a is formed by narrowing the tip inward through compression processing, etc.
At the same time, the inner circumferential surfaces of the four parts are formed to have curved surfaces that match the generatrix of the spherical surface.

However, according to such conventional processing methods, the outer periphery of each raw material is not uniform when hammered, and when suppressing processing is performed with an upsetter, etc., the forming occurs when the tip is narrowed inward. As shown by arrow A in Figure 2, a force is applied to the groove in the part corresponding to the bending part in the direction of widening the width of the groove, and the width of the groove is not constant. In some cases, it is necessary to finish the grooves by cutting and/or polishing, which has the drawback of poor productivity and high costs.

In order to solve the above-mentioned drawbacks, the present invention makes it possible to precisely create a reverse slope in the groove by ironing the preformed rough material, and at the same time, it is possible to make the inner circumferential surface a curved surface that matches the spherical surface. The purpose of the present invention is to obtain a processing mold that can be processed in a radial direction, and in order to achieve this purpose, the present invention has a plurality of radial molds attached to either the upper mold or the lower mold so that the lower mold can be moved in the radial direction. At the same time, a lock pin that can be moved up and down is fitted in the center of one of the molds.
The tip of this locking pin can be moved in and out of the radially arranged lower mold, and the other mold has a plurality of grooves formed in the raw material in cooperation with one of the molds. It is characterized in that a protrusion is provided for ironing the outer circumferential surface corresponding to the intermediate portion of the grooves adjacent to each other.

An embodiment of the present invention will be described below with reference to the drawings.

In FIGS. 4 to 6, 3 and 4 are molds that form a pair with each other, of which 4 is one mold of the pair (lower mold in this example), and 3 is the other mold of the pair (lower mold in this example). In the example, it is the upper type).

The upper die 3 has a protrusion 5 formed on its inner circumferential surface for squeezing the outer circumferential surface of the preformed rough material 1°. A plurality of grooves 2a formed on the inner circumferential surface of the rough material 1° shown in the figure are provided at intervals that can squeeze the outer circumferential surface corresponding to the intermediate part of the mutually adjacent grooves, and the state of the protrusion is as follows. It may be formed only at the tip of the inner circumferential surface of the upper mold 3, or may be formed in a long protruding shape all the way to the back. In addition to the above example, the protrusion is provided with an annular protrusion on the entire circumference of the tip of the inner circumferential surface of the upper die, and is further formed on the inner circumferential surface of the rough material on the protrusion as in the above embodiment. The gutter 1 portion may be formed so that the outer circumferential surface corresponding to the intermediate portion of the adjacent grooves of the plurality of grooves can be made stronger than the other outer circumferential surfaces.

Furthermore, an eject pin 6 is fitted in the center of the upper mold 3 for extruding the forged part 1 attached to the upper mold 3 after processing.

On the other hand, on the lower mold 4, a plurality of lower molds 7 formed to correspond to the grooves 2a of the rough material 1' shown in FIG. There is. This retainer 8 has a plurality of holes radially arranged therein, and the lower part of the lower mold T is slidably fitted into each hole. Also,
A coil spring 10 whose biasing force can be adjusted by means of a screw 9 is disposed in the hole, and the coil spring 10 always biases the lower die 7 in the centripetal direction.

A 111dO lock pin is fitted into a hole provided in the center of the lower mold 4 so that it can move up and down, and a groove 12 is provided at the tip of this lock pin 11 to fit with the back surface of each lower mold 7. be.

Next, to explain the operation of the processing mold having the above-mentioned configuration, first, as shown in FIG. Cover with the preformed rough material 1'' shown in Figure 3.
The groove 2a shown in the figure and the lower die 7 are fitted together. At this time, since the groove 2a has not yet been given a reverse slope, the lower mold 7 can be easily inserted into the groove 2a.

Here, the rough material 1° may have the same shape as the one shown in FIG. .

Next, the upper mold 3 is lowered as shown in FIG. As the upper die 3 descends, each protrusion 5 squeezes the middle part of the adjacent grooves 2a of the rough material 1'', and the lower part of the groove 2a supported by the lower die 7 is given a reverse slope with precision. At the same time, the inner circumferential surface can be formed into a curved surface that matches the spherical surface.During this squeezing operation, 1. As mentioned above, in order to squeeze the middle part of each nest with the protrusion 5, the inner circumferential surface can be formed into a curved surface that matches the spherical surface. The precision of the grooves 2 becomes extremely high by applying a force to the inner surface of each groove 2 and bringing the inner surface of each groove 2 into close contact with each nest.

After processing the rough material to 1° in this way, when the lock pin 11 is lowered by a predetermined amount as shown in FIG. to remove it from groove 2. At that time, the end surface 7a of the lower die 7
comes into contact with the stepped surface 7b provided on the lock pin 11 and stops. Then, when the upper die 3 is raised, the processed forged part 1
can be easily taken out from the lower mold 7. At this time, the forged part 1 normally rises while adhering to the upper die 3, so it is pushed out and released from the die by moving the eject pin 6 downward at the upper die's raised position or during the rising process.

In the above-described embodiment, in order to ensure that the lower die 7 comes out of the groove 2 of the forged part 1 with a reverse slope, the lock pin 11 is set to prevent the lower die 7 from interfering with the batter. In order to do this, as shown in FIG. 6, the relationship between the depth a of the curved surface portion of the lower inserting mold 70 and the amount of movement of the lower inserting mold 7 is set such that a<b. Alternatively, a stopper groove 14 may be provided on the lower surface of the lower mold 7, and a stopper pin 15 that engages with the stopper groove 14 may be provided on the lower mold 4, and the amount of movement of the lower mold 7 may be limited by both. good.

Further, the means for biasing the lower mold 7 in the centripetal direction is not necessarily limited to the coil spring 10, and for example, a hydraulic cylinder mechanism, a cam mechanism, a link mechanism, etc. may be used.

The upper surface of the retainer 8 may be flat, but if it is made into an inclined surface 16 as shown in the figure, this inclined surface 16 will not resist the flow of meat near the outer peripheral surface of the tip of the rough material 1° during ironing. Therefore, it is advantageous in preventing forging defects such as curling.

Furthermore, the upper mold in the above-described embodiment can be used as the lower mold, and the lower mold can also be used as the upper mold. In that case as well, the preformed rough material can be set in the lower mold or the upper mold, and the ironing process can be performed by lowering the upper mold.

□ The processing mold according to the present invention described above is provided with a vertically movable lock pin inside the radially movable lower mold provided on one mold, and a lock pin that is movable vertically inside the lower mold provided on the other mold. A protrusion is provided at a position corresponding to the middle of each nest, and by using the protrusion to squeeze the outer circumferential surface corresponding to the middle part of each groove of the rough material, a force is applied in the direction of making the straight groove closely adhere to each nest. Since the inner peripheral surface is pressed against the curved surface corresponding to the spherical surface to create a reverse slope while simultaneously forming the groove, it is possible to create grooves with a reverse slope with high precision.

Therefore, the dimensional accuracy of the forged raw material, which is a formed forged part, is significantly improved, and cutting and polishing are not required, so the number of manufacturing steps is significantly reduced and the manufacturing price is also low. It is highly effective in manufacturing forged parts with grooves of opposite slope, such as the outer race of constant velocity joints.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view showing an example of a forged part having grooves with a reverse slope, Fig. 2 is a cross-sectional view taken along the line ■-■ in Fig. 1, and Fig.
The figure is a longitudinal sectional view showing an example of preformed rough material, FIGS. 4 to 6 are longitudinal sectional views showing the structure and operation of one embodiment of the processing mold of the present invention, and FIG. FIG. 8 is a plan view of a certain upper mold, and a longitudinal sectional view showing another example of the rough material. 1...Forged part 1°...Rough material 1a...Concave part 2
...Reverse slope groove 2a...Straight groove 3
...Upper mold which is the other mold 4...Lower mold which is one mold 5...Protrusion 6...Eject pin 7...Lower mold 8...Retainer 10...Coil spring 11...Lock pin patent applicant Nissan Motor Co., Ltd. agent Patent attorney Takashi Kanakura Nikaku 1r3A -゛・, 2 noodles 22 noodles 41 3 ++1 7', 'Iris, τ' noodles 5; I'11R100' )0.1.J4 j)υ(O)
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Claims (1)

[Claims] One of the molds in the pair is capable of radially sliding a plurality of nested molds that are formed to correspond to the multiple grooves with no reverse slope that have been preformed on the inner peripheral surface of the four parts of the rough material. A lock pin is fitted in the center of the mold so as to be able to slide in the forging direction, and a lock pin is fitted in the center of the mold so as to be able to slide in the forging direction. Forging of a part having grooves with a reverse slope, characterized in that a protrusion is provided to give a reverse slope to the plurality of grooves without a reverse slope by squeezing the outer circumferential surface corresponding to the intermediate part of adjacent grooves. Type.