JP2701277B2 - Work processing method - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a work processing method for performing preforming, cold sizing, and back turning, and in particular, to processing of cold sizing and back turning, respectively. This provides a sufficient improvement in accuracy. (Prior Art) In the conventional cold sizing in this type of work processing method, a work which has been preformed is completed, for example, a work W for a differential gear for automobiles as shown in FIG. Is on its tooth profile forming surface 1,
After sequentially forming a zinc phosphate film and a metal soap film, the tooth forming surface 1 of the work W is directly fitted into the cavity 3 of the sizing die 2 shown in a sectional view in FIG. It is done by that. At this time, at the time of such cold sizing, the metal soap transferred from the work W to the peripheral surface of the cavity of the sizing die 2 is removed from the work W by sizing for each sizing. (Problems to be Solved by the Invention) However, in such a conventional technique, as shown in an enlarged sectional view in FIG. 4 (b), the thickness unevenness is considerably large, and the film thickness is relatively large. Since cold sizing is performed while the thick metal soap film 4 is kept attached to the tooth profile forming surface 1 of the work W, when the work W is fitted into the cavity 3 of the sizing die 2, the fifth process is performed. As shown in the enlarged cross-sectional view in FIG.
In particular, the unevenness of the thickness often hinders accurate fitting of the tooth profile forming surface 1 into the cavity, and when the sizing die is performed under such a condition, the metal soap film 4 becomes There is a problem that it acts as if it were a part of the die 2 and causes a reduction in processing accuracy. Further, even after the end of the cold sizing, the metal soap film 4 adhering to the tooth profile forming surface 1 is subjected to the sixth turning of the tooth profile in order to perform back turning on the work W which has finished the cold sizing. Even when the work sheet 5 is seated under pressure on the processing sheet 5 as shown in the cross-sectional view of FIG. 6A, the thickness of the metal soap film 4 is uneven. As shown, the accurate seating of the tooth portion on the working sheet 5 is impeded, which causes a problem that the turning accuracy also decreases. In particular, the decrease in the turning accuracy is caused by the cold sizing. Since this occurs at the same time as the reduction in processing accuracy, a processing error that is much larger than expected may be caused in the final product as a processed work. The present invention has been made by paying attention to such a problem of the conventional technology, and can sufficiently improve the processing accuracy of the cold sizing, and can also sufficiently improve the accuracy of the backside turning. Another object of the present invention is to provide a work processing method capable of sufficiently removing a decrease in accuracy of a final product caused by accumulation of processing errors. (Means for Solving the Problems) According to the work processing method of the present invention, a zinc phosphate film and a metal soap film are sequentially formed on a pre-formed work, in particular, on a formed surface thereof, and the metal is formed. The thickness of the soap film is made evenly uniform by shot blasting, hot water washing, pickling, etc., and then the work is placed in the cavity of the sizing die with a metal soap film of uniform thickness. Then, cold sizing is performed by fitting the workpieces, and the work after the cold sizing is seated on a processing sheet via a metal soap film having a uniform thickness to perform backside turning. (Function) In the method of the present invention, a zinc phosphate film and a metal soap film are formed on a work which has been preliminarily formed.
Generally, it is possible to sufficiently remove the risk of thermal decomposition, physical destruction, etc. of those films during the preforming performed warmly, and to homogenize the metal soap film formed on the work. The thickness of the workpiece can be made sufficiently uniform and can be made extremely thin. The metal soap film located between them,
There is no risk of preventing proper fitting into the sizing die, and therefore, cold sizing can always be performed with high accuracy. The same applies to the case of turning the back surface, and the thickness of the metal soap film sandwiched between, for example, the tooth shape portion and the processing sheet of the work after cold sizing is sufficiently uniform throughout. , And by being extremely thin, the tooth profile can always be properly seated on the processing sheet, and the turning accuracy,
As a result, the processing accuracy of the final product can be significantly improved. Embodiment An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a process drawing showing an embodiment of the present invention, and a portion surrounded by a two-dot chain line in the drawing is a portion according to the present invention. For example, when manufacturing a differential gear for an automobile, first, a material made of SCM418H is cut into required dimensions to form a work, and then the work is
Preliminary shaping of the teeth is performed by warm forging under heating at 800 to 900 ° C, and then the preformed work is shot blasted with steel balls of 0.5 to 1.0 φ, and the scale is scaled from there. Remove. Further, the magnetic inspection and the appearance flaw check of the work and the non-oxidizing normalization are successively performed successively.
Heating to 0 ° C. for 1 hour and then allowing it to cool causes a decrease in its hardness. Furthermore, a zinc phosphate film and a metal soap film are sequentially formed on the work, particularly on the tooth forming surface thereof, for the purpose of improving the slip of the work against the sizing die and preventing the work from galling. , And the thickness of the metal soap film, for example, the average particle size is about 0.3 m
The steel ball of m is shot-blasted for 1 to 2 minutes to make it evenly uniform over the entire work by making it uniform, and it is also extremely thin. In this case, the film thickness can be made uniform by positively cleaning the metal soap film, particularly the convex portions. According to this, as shown in the enlarged sectional view of FIG. 2, the thickness of the metal soap film 12 adhered to the surface of the preformed tooth profile 11 of the work W is sufficiently uniform and the thickness is significantly reduced. Subsequently, when the work W is subjected to cold sizing, the metal soap film 12
As shown in the enlarged cross-sectional view in the figure, it is possible to sufficiently secure the work W, and thus the preformed tooth profile 11 to the sizing die 2 properly. Therefore, cold sizing is performed with very high precision through a uniform thin film of metallic soap, which acts like a part of a sizing die. Note that, here, the homogenization treatment by shot blast is intended to bring both the uniformity of the film thickness of the metal soap film 12 and the thinning, but in the present invention, at least the film thickness is made uniform, and By configuring the sizing die 2 in consideration of the film thickness, the object can be sufficiently achieved. After performing high-precision cold sizing in this way, for example, an accuracy check for tooth groove runout, pitch error, and the like is performed. Back turning is performed by sitting on a processing sheet similar to that described in the example. Here, the work W
Since the metal soap film 12 still adhering to the surface even after the end of the cold sizing has a sufficiently uniform thickness, the working sheet is substantially similar to the case shown in FIG. You can sit with high precision,
Turning accuracy can also be significantly improved. Then, as described above, the work W as a final product subjected to high-precision cold sizing and back turning is subjected to carburizing quenching and polishing sequentially, and subsequently, a final accuracy check is performed. This completes a series of forging operations. In the case of manufacturing a forged product as described above, in particular, the accuracy of the cold sizing and the backside turning is significantly improved as compared with the prior art by the uniform treatment of the film thickness of the metal soap film 12. Can be increased,
Even if the processing errors of the respective processes are superimposed, the inspection pass rate in the final accuracy check is greatly improved. In the above description, the metal soap film is homogenized by shot blast. However, even if the homogenization process is performed by hot water washing or pickling, the same operation as shot blasting is performed. Can bring effects. (Effects of the Invention) Therefore, according to the present invention, in particular, the metal soap film formed on the surface of the work is made uniform by the homogenization treatment, so that the work is fitted into the sizing die and processed. Since the seating on the vehicle seat can always be properly performed, the cold sizing and the backside turning can be performed with extremely high precision as compared with the related art. In addition, since cold sizing can always be performed with high precision, even if the processing error of the cold sizing may overlap with the processing error of the backside turning, the processing error of the final product should be sufficiently small. Becomes possible.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a process drawing showing an embodiment of the present invention, FIG. 2 is an enlarged sectional view showing a uniform state of a metal soap film, and FIG. 3 is fitting a work into a sizing die. FIG. 4 is a view showing a state where the work is fitted into a sizing die, and FIG. 6 is a view showing a state where the work is seated on a processing sheet. . W: Work, 2: Sizing die 11, Preformed tooth profile, 12: Metallic soap film

Claims (1)

(57) [Claims] A zinc phosphate film and a metal soap film are sequentially formed on the preformed molding work, and after the metal soap film is subjected to a uniform film thickness treatment, the work is placed in the cavity of the sizing die. , Cold sizing by fitting through metal soap film of uniform thickness,
Further, a work processing method characterized in that the work after cold sizing is seated on a working sheet via a metal soap film having a uniform thickness to perform backside turning.