JPS6317882B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for compressing sintered machine parts in a recompression process after sintering them, for the purpose of improving dimensional accuracy, increasing density, or modifying the shape if necessary. Regarding the resizing method.

Generally, during the recompression process after sintering sintered machine parts, unlike the powder compression molding process, the sintered body that has already been shaped is recompressed, so how can it be accurately and quickly molded? The ability to charge is an important point in manufacturing technology.

Conventionally, the charge method in the recompression process of sintered bodies uses a rotary table or index table, etc., and performs a primary charge on the table.
A method is known in which the punch center is charged while rotating it intermittently, or a method in which the feed shot is first charged and then the punch center is charged.

However, charging to the punch center requires positional accuracy, and as a countermeasure to this, a guide portion is provided.

That is, when pressurizing the sintered body 01 within the effective diameter 02a of the die 02 for the recompression process as shown in FIG. The shoe 03 is conveyed to the center and kept stationary on the punch center as a die guide, and is moved forward or backward as the upper punch 04 and the lower punch 05 operate as shown in the show motion in FIG.

Further, since the die guide portion and the die 02 are integrated as shown in FIG. 3, charging of the sintered body 01 is performed by a show motion as shown in FIG. 4.

However, in any of the above cases, a conveyance machine from the primary charge to the punch center, which is the secondary charge, is required, and the complicated structure makes handling difficult, resulting in low productivity and high cost.

The present invention was made in view of the above-mentioned circumstances, and eliminates the need for a complicated conveyance mechanism, eliminates the time required to charge the sintered body, and enables a highly accurate and reliable recompression process. This provides a sheerless sizing method.

Embodiments according to the present invention will be described below with reference to FIGS. 5 to 1.
This will be explained in detail based on FIG.

5a and 5b are sectional views of the main parts of the device according to the present invention when the upper ram is attached and pressurized, in which 1 is a punch holder, 2 is a core holder, 3 is a core,
4 is the upper punch, 5 is the spring, 6 is the lower punch,
7 is a die.

The die 7 is formed into a shape having a partially cut-out holding portion 7a as shown in FIGS. 6a, b, and c, and is assembled as shown in FIGS. 7 and 8.

Sintered bodies 10 are sequentially fed into the holding portion 7a of the die 7 via an inclined shooter 9 connected to an alignment device 8 such as a parts feeder and charged. Holding part 7
The sintered body 10 is recompressed by the effective diameter portion 7b formed below a by the pressing process of the upper and lower punches 4 and 6, and after completing the predetermined straightening process, the sintered body 10 is compressed by the cam 11 provided on the main shaft. Link mechanism 12
It is discharged by

In order to prevent the sintered compact 10 waiting to be charged from moving onto the punch center which has already been charged and is undergoing a pressurization cycle, the operation of the device according to the present invention starts from the start of the extraction process to the product as shown in FIG. A curve is set so that the escape speed of the upper ram becomes very slightly faster until it appears on the table, and the difference is H-D=A as shown in Figure 10.
Keep it within the range.

As a result, the sintered body 10 does not move until immediately after the lower punch 6 falls. In addition, the sintered body 10 waiting to be charged comes into contact with the upper and lower punches 4 and 6 and the product after straightening, but since the outer diameter of the compact is usually chamfered, the outer diameter end surfaces of the upper and lower punches 4 and 6 However, as shown in Fig. 16, the outer diameter end faces of the upper and lower punches 4 and 6 should be chamfered by 10° to 20° within a range smaller than the product chamfer amount (T). t) gives even better results.

Next, a press cycle in the apparatus configured as described above will be explained in detail based on FIGS. 11 to 15.

As shown in FIG. 11, the sintered compact 10 fed from the shooter 9 is charged to the holding part 7a of the die 7, and as shown in FIG. 7 effective diameter portion 7b
The dimensions are corrected. Thereafter, as shown in FIG. 13, the upper punch 4 rises as the lower punch 6 rises, and the sintered body 10 is extracted, and is ejected as shown in FIG. 14 by a separate ejection device consisting of a cam and a link mechanism. Then, the lower punch 6 descends, and at the same time, the next sintered body 10 is charged as shown in FIG. That is, at the same time as the lower punch 6 descends, the sintered body 10 on the shooter 9 moves one position due to gravity and is charged into the holding portion 7a of the die 7.

As explained in detail above, the shewless sizing method according to the present invention does not require a table, a shew, etc., when charging a sintered body during the recompression process after sintering sintered machine parts. Instead of forming a holding part for the sintered body on the die in advance,
The sintered body is sequentially fed into the holding portion from an inclined shooter, and the sintered body can be accurately and quickly charged into a predetermined mold.

Further, the charging mechanism for the sintered body during the recompression process is simple, and dimensional accuracy can be improved, and productivity can be improved.

[Brief explanation of the drawing]

1 to 2 and 3 to 4 are sectional views showing a conventional embodiment in a charging state and explanatory views of show motion, and FIGS. 5a and 5b are sectional views of main parts showing an apparatus according to the present invention. Figure 6a,
b, c are top views, cross-sectional views, and perspective views of the die according to the present invention; FIGS. 7 and 8 are explanatory diagrams showing the main parts of the device according to the present invention; FIG. 9 is a show motion diagram showing the operating state according to the present invention. Explanatory drawings, FIG. 10 and FIG. 16 are explanatory drawings of main parts according to the present invention, and FIG.
15 through 15 are explanatory views of the press cycle of the apparatus according to the present invention. 1...Punch holder, 2...Core holder,
3...Core, 4...Upper punch, 5...Spring, 6...Lower punch, 7...Die, 7a...Holding section, 7b...Effective diameter section, 8...Aligning device, 9...
Shooter, 10... Sintered body, 11... Cam, 12
...Link mechanism.

Claims (1)

[Claims] 1. In the charging method in the recompression process of the sintered body, a holding part that is partially cut out is formed in the upper part of the effective diameter part formed on the die that charges the sintered body, and a holding part of the die is provided with a part that is inclined from the parts feeder. A shoeless sizing method characterized in that sintered bodies are sequentially fed through a shoer.