JPS61129242A - Cross rolling work method - Google Patents

Abstract

PURPOSE:To eliminate the unbalance in a forming force and to obtain the product of high accuracy by taking the method of performing the formation of the main shaft part and big diameter part after preceding the formation of the small diameter part of the shaft end in case of subjecting the shaft with non-symmetrical step to a cross rolling work. CONSTITUTION:The extension line of the center line l1 in the longitudinal direction of the main shaft part 1a of the final product is taken as the biting start part 1e. The process of the formation in the axial direction is suspended once at the initial stage of the formation of immediately after the first forming die part 12a having bitten a blank W and the formation of the small diameter shaft part 1d by the second forming die part 12d is preceded. In this case, the chamfering 1f of one part of the large diameter shaft part 1c by the third forming die part 12e and the formation by equalizing part 12g are to be completed. After completion of the formation of the shaft part 1d the formations of the main shaft part 1a and medium diameter shaft part 1b by the die part 12a and the formation of the large diameter shaft part 1c by a reference face 12c are performed simultaneously. The product of high accuracy is thus obtd. without causing the unbalance in forming force.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a cross-rolling method used mainly for forming stepped shafts as one type of rolling.

2. Related Art For example, as shown in FIG. 4, a main shaft portion 1a is provided with a medium diameter shaft portion 1b and a large diameter shaft portion 1C at both ends, and a small diameter shaft portion 1dt is further provided on the end face of one of the large diameter shaft portions 1C. In the case of forming by the next stepped shaft St-cross rolling process, the following method is used. In addition, the medium diameter shaft portions 1b and 1b, the large diameter shaft portions 10 and 10, and the main shaft portion 1& and the small diameter shaft portion 1.
Both have the same diameter as d.

As the material for the stepped shaft S shown in Fig. 4, it is common to use a material with a diameter that is the same as or slightly larger than the diameter of the large-diameter shaft portion 1C, and in this case, the roller die may bite. The setting position of the section is set at the section where the reduction ratio in the radial direction is the largest. In the case of the stepped shaft S shown in Fig. 4, there is a small diameter shaft part 1d in addition to the main shaft part 1a as a part with a large reduction ratio in the radial direction. As shown, the dimensions of each part of the roller die 2 Q1.
The reference line 't- is set under the condition that Ql, Ql satisfies Q+ +Qt = Ql, and the above-mentioned biting portion is set on the extension line of this reference 41K.

To be careful, the biting part is offset to the left side in FIG. 5 from the longitudinal center line of the main shaft part 1a of the stepped shaft S, which is the final molded product, and is located at the next position. The molding die part 2a with a mountain-shaped cross section that controls the molding is standard 11K.
The left and right sides are asymmetrical.

In other words, in the right half of the molding die section 2a centered on the biting part (reference line K), the main shaft part 1a and the medium diameter shaft part 1b are formed, whereas in the left half, the main shaft part 1a and the medium diameter shaft part 1b are formed. After the shaft portion 1bt is molded, the small diameter shaft portion 1dt is molded.

Problems to be Solved by the Invention According to the method shown in FIG. 5, for example, if the processing progresses to the S1 position It and then assumes that the forming force F1 on the left side and the forming force F1 on the right side are the same as shown in FIG. , the forming force F on the right side is larger. If there is a difference between the left and right forming forces, the material being formed is pulled by the side with the greater forming force (toward the right in FIG. 5), resulting in a decrease in dimensional accuracy.

The present invention focuses on the fact that dimensional accuracy is more stable when molding is performed in a symmetrical manner. This is an attempt to provide a cross rolling processing method that actively incorporates ideas.

tth Means for Solving the Problems The present invention has the following features: 1. A main shaft portion has large diameter portions having a larger diameter than the main shaft portion at both ends, and the large diameter portion is provided on the end face of one of the large diameter portions. This is a cross rolling processing method that forms a next stepped shaft with a small diameter part that is smaller in diameter than the diameter part, and the material is bitten into the material near the longitudinal center position of the main shaft part in the final molded product shape as the starting part. The molding progresses symmetrically,
It is characterized in that the progress of forming in the axial direction is temporarily interrupted in the initial stage of forming after the start of biting, and forming of the small diameter portion is performed first.

In other words, the small diameter section at the end of the shaft is formed first, and then the main shaft section and large diameter section are formed. Do not restrict the small diameter part.

In this case, the large diameter portion includes not only one stage but also two stages.

Effect By using such a method, when forming the main shaft portion and the large diameter portion, it is possible to form the main shaft portion and the large diameter portion in a substantially bilaterally symmetrical form without considering the small diameter portion, and an imbalance in forming force does not occur.

Embodiment FIGS. 1 and 2 are diagrams showing an embodiment of the present invention. FIG. 2 shows a developed view of the roller die, and FIG. It shows. As shown in FIGS. 1 and 2, the Radice 12 has a reference surface 12C for forming the large diameter shaft part IC (see FIG. 4), as well as a reference surface 12C for forming the main shaft part 1a and the medium diameter shaft part 1bt. A first molding die part 12& for forming the small diameter shaft part 1dt, a second molding die part 12d for forming the small diameter shaft part 1dt, and a molding die part 12d for chamfering the end face of one large diameter shaft part 1C as described later. The tip of the first molding die part 12a is a biting part 12f, and the entire first molding die part 12a extends left and right with respect to the extension line of the biting part 12f. It has a symmetrical shape.

Further, the second molding die portion 12d and the third molding die portion 12e are formed at positions substantially corresponding to the length of the uniform portion 12g having a constant width in the first molding die portion 12a.

In this embodiment, as shown in FIG. 1, the longitudinal centerline 1. Forming is started by biting the cylindrical material W using the extension @ as the biting start part 1e. In this case, the introduction part 12h (Fig. 2) where the width of the die part gradually increases! : Although the forming of the material W in the longitudinal direction progresses until the time elapses, the progress of forming the material W in the longitudinal direction is interrupted when the width reaches the uniform portion 12g, and the second forming die portion 12d and the third forming die portion 12d Molding is started using the molding die section 1213 (Fig. 1 ■))
.

That is, at the initial stage of forming immediately after the first forming die part 121L bites the material W, the progress of forming in the longitudinal direction is temporarily interrupted, and the second forming die part 12dK instead forms the small diameter shaft part 1d. precede. In this case, as shown in FIG. 3, F! In response to the flow of material in the force direction, a flow of material in the F direction is generated, thereby causing F! Prevents excessive material from flowing in the direction of force.

Further, in parallel with the molding of the small diameter shaft portion 1d, a chamfer 11 is applied to the end face of one of the large diameter shaft portions IC using the third molding die portion 12e. The flow of material in the f direction caused by this chamfering prevents the wood W from moving in the axial direction during forming. As shown in FIG. 2 and FIG. 1(c)K, the second molding die part 12d and the third molding die part 12e are cut off and l The molding of the diameter shaft portion 1d and the chamfered portion 1f is completed,
Finished to specified dimensions.

After completing the molding of the small diameter shaft portion 1d, the first rIAC3~
As shown in [F], only the first molding die part 12& is used for molding, and the main shaft part 1a and the medium diameter shaft part 1b are molded by the first molding die part 12aK, and at the same time, the reference surface 12
A larger diameter shaft portion 1C is formed from cK. In this case, as is clear from ◎ to [F] in Fig. 1, the small diameter shaft portion 1d, which has already been formed, is not restrained in any way, so the material W
K means that the molding progresses symmetrically across the center line tIt, and therefore the distribution of molding force is also equal on both the left and right sides.

Here, in this embodiment, the large diameter shaft portion 1C is used as the large diameter portion.
Although the example shows a stepped shaft with 92 steps and a medium-diameter shaft portion 1b, the same procedure can be applied to a stepped shaft with only a large-diameter shaft portion 1C or a small-diameter shaft portion 1b. can.

Effects of the Invention As described above, according to the present invention, the main shaft part and the large diameter part are formed after the small diameter part of the shaft end is formed first, so that when forming the main shaft part and the large diameter part, 74%
Since the molding can be performed in a symmetrical manner without considering the diameter, high-precision machining can be performed stably without creating an imbalance in the molding force.

[Brief explanation of drawings]

Fig. 1 is a process explanatory diagram showing one embodiment of the present invention, Fig. 2 is a developed view of a roller die used in the method of Fig. 1, and Fig.
The figure is an enlarged view of Figure 1 CB), Figure 4 is an explanatory diagram showing an example of a stepped shaft, Figure 5 is an explanatory diagram showing a conventional forming method, and Figure 6 is an explanatory diagram showing an example of a stepped shaft.
The figure is an enlarged view of the main part of FIG. S...Stepped shaft, 1a...Main shaft part, 1b...Medium diameter shaft part (large diameter part), 1C...Large diameter shaft part (large diameter part), 1d.
... Small diameter shaft part (small diameter part), 1e... Biting start part,
12... Roller die, 12a... First forming die part, 12d... Second forming die part, 12e...
Third molding die part, 12f... biting part, W...
·material. Outside 2 stones Figure 2 α1 Figure 3

Claims (1)

[Claims] (1) A stepped structure having a large diameter part larger than the main shaft part at both ends of the main shaft part, and a small diameter part smaller than the large diameter part on the end face of one of the large diameter parts. In the cross-rolling processing method for forming a shaft, the material is bitten in the vicinity of the longitudinal center position of the main shaft part in the final molded product shape as a biting start point, and the forming progresses symmetrically, and the forming after the biting starts. The process is characterized in that the progress of forming in the axial direction is temporarily interrupted at an initial stage, and the forming of the small diameter part is carried out first, and after the forming of the small diameter part is completed, the forming of the main shaft part and the large diameter part is proceeded symmetrically. Cross rolling processing method.