JP2826464B2 - Forging method and forging device for crown-shaped parts - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to relates to a forging device forging method of the coronary part suitable for the manufacture of detection Li <br/> in g torque sensor.

[0002]

2. Description of the Related Art In automobile power steering, as shown in FIG.
Detection rings 105 to 107 made of electromagnetic stainless steel are externally fitted to a connection portion between the input shaft 101 and the output shaft 103, and a detection coil 109 is arranged on the outer periphery thereof.
A torque sensor that detects a steering torque based on a detection signal from a motor 9 is known.

The detection rings 105 to 107 have a complicated shape having a large number of crown-shaped projections.
7, the powder of electromagnetic stainless steel is compacted and sintered;
Finally, a method of manufacturing by cutting the surface was adopted.

However, there is a problem that the production by sintering requires a lot of man-hours. Also, with the rapid progress of electronic control technology in recent years, there is a demand for further improving the detection accuracy of the torque sensor. However, conventional products have a limit in detection capability, and parts with higher detection capability have been desired.

[0005] Therefore, the present invention has an object that you provide a forging method and forging apparatus suitable for the manufacture of the detector ring for high torque sensor of detection capability is inexpensive.

[0006]

[0007]

[0008]

Forging method of the coronary part of the SUMMARY, and action to solve the present invention, the coronal part having a projection extending in the axial direction to an end portion of the-ring to a method for cold forging, to the material blank In the first forging step, a portion corresponding to the crown projection is directly formed, and in the first forging step, forging is performed while generating extra thickness at the outer peripheral portion of the crown projection.

Here, in general, when forging a part having a part having a complicated shape, the body part is formed first in the first step, and a part having a complicated shape is formed later. Such a method is adopted. In addition, in such a general forging method, the punch and the die are closely attached so that there is no excess
A device designed to fit is used. Therefore,
In describing the operation of the forging method of the present invention, assuming a method of forging a crown-shaped part by applying this general forging method,
Description will be made in comparison with this.

[Significance and Action of Forming Crown in First Step] According to the forging method of the present invention, a portion corresponding to the projection of the crown is formed in the first forging step. In the first forging step, the material blank has not undergone work hardening. Therefore, even when cold forging is performed, it is possible to suppress the load on the punch and the die when forming the crown projection. On the other hand, in a general forging method, a portion having a complicated shape is formed after work hardening occurs.
Therefore, punching and dies are liable to be damaged when cold forging is performed as it is. To prevent this, other processing such as annealing is required, which causes an increase in man-hours.

[Significance and Action of Forging While Properly Producing Extra Surplus in the Outer Peripheral Part ] According to the forging method of the present invention, in the first forging step, the product is added to the outer peripheral part of the crown projection. The forging of the crown portion is performed while creating extra thickness. By generating excess material, the flow of meat when forging a complicated shape is smoothened. In other words, when a complicated shape is to be formed immediately, a general forging method that does not cause excess wall does not allow the meat to sufficiently flow into the cavity formed by the punch and the die. Is easily lost. To eliminate this, it is necessary to take measures such as increasing the forging load, which also imposes a burden on punches and dies. In contrast, the forging method employed in the forging method of the present invention for forging while positively generating excess thickness enables a component having a complicated shape to be formed without a missing portion without increasing the forging load. .

As described above, according to the forging method of the present invention,
By adopting both of the above-mentioned two characteristic configurations, a crown portion having a complicated shape can be easily and reliably formed before work hardening occurs. Even before the work hardening, if the crown portion is forged by a method that does not cause excess thickness, there is a possibility that a portion where the thickness of the meat is insufficient is generated.

By the way, the extra thickness generated at the outer peripheral portion of the projection may be removed by cutting when dimensional accuracy is obtained in the finishing step. This finishing step is necessary even in the case of a conventional sintered product, and the production of excess thickness by the method of the present invention does not lead to an increase in man-hours. In addition, it goes without saying that the forging method of the present invention is suitable for manufacturing a detection ring for a torque sensor as intended by the present invention,
However, the present invention is not limited to this, and it is also possible to apply the present invention to the manufacture of a clutch component that is engaged by a crown-shaped mesh. In addition, it can be applied to the production of various crown-shaped parts.

[0014] On the other hand, forging device coronary part of the present invention made in order to achieve the above Symbol purpose is a device for cold forging a coronal component having a projection extending in the axial direction to an end portion of the ring, A punch having projections and depressions for forming the projections, and a die fitted to the punch, wherein the punch and the die are formed so that the projections and depressions of the punch are loosely fitted to the die. Is characterized in that a gap at the time of fitting is formed.

According to this forging device, when forging the crown portion, the clearance promotes escape of the meat. As a result, excess thickness is generated, but the excess thickness may be removed by cutting at the time of final finishing. If the forging device of the present invention is used in the first step of forging, the above-described forging method of the present invention can be easily implemented.

It should be noted that the forging device of the present invention is not only applicable to the forging method of the present invention, but also employs a procedure of forming a crown portion in the second and subsequent steps. Needless to say, it can be used as a device. Even if the material is work-hardened, it is possible to suppress an increase in the forging load by smoothing out the meat, and it is possible to obtain effects such as prolonging the punch life when used in such a method.

[0017]

Next, as a preferred embodiment to which the present invention is applied,
As shown in FIG. 1, a protrusion 5 extending in the axial direction is provided at an end of the cylindrical body 3.
A method and an apparatus for manufacturing the detection ring 1 for a torque sensor having the above by cold forging will be described.

In the examples, as a material, 1 of the composition shown in Table 1 was used.
3Cr electromagnetic stainless steel was used.

[0019]

[Table 1]

As shown in FIG.
In contrast, in the first forging step (upsetting), the crown projection 11 is directly formed, and in the second forging step (rearward extrusion), the cylindrical body part 12 is formed, and the third forging step ( The bottom 13 of the ring main body is pulled out by punching. In the meantime, in the first step, as shown in the figure, forging is performed while generating extra thickness 15 on the outer periphery of the protruding portion 11 of the crown. FIG. 2D is not completed yet, and thereafter, the surplus portion 15 is cut off and the surface is cut as a finishing process to complete the product.

Next, in the first forging step, as shown in FIG. 3, a forging comprising a punch 20 having irregularities 21 for forming a crown projection and a die 30 fitted to the punch 20 is performed. Use the device. Here, the punch 20
As shown in FIG. 4, the unevenness 21 at the tip is thinner than the main body 23. That is, as can be seen from the AA cross section and the BB cross section, a step 25 is formed between the outer wall of the main body 23 and the outer wall of the uneven portion 21 so as to enter about 1 mm inward. Therefore, when the elaborate laid the punch 20 in the die 30, it is ing the gap portion of the step 25. this
When forging a crown of projections at device, the write Mukoto relief meat material in the gap is <br/>, the outer periphery of the crown projection, cause excess thickness
You. That is, the punch 20 and the die 30 can form a crown portion by inducing flesh escape at the time of upsetting, and positively generating the extra thickness 15 on the outer periphery of the projection of the crown.

By using the punch 20 and the die 30, in the first forging step, the meat of the material blank W swells up firmly in the recesses of the unevenness 21 of the punch 20, and the portion 11 hitting the projection of the crown has a serious defect. No parts occurred. Further, it was also found that an excessive forging load was not applied to the punch 20 and the die 30 and that the punch 20 and the die 30 could withstand mass production.

Next, a detection ring for a torque sensor according to a comparative example was manufactured by pulverizing the above-mentioned material, compacting the same, and sintering it. Then, the detection capabilities of the detection rings of the example and the comparative example were compared. In comparing the detection capabilities, the magnetic properties of the two rings were measured with various gaps. The result is shown in FIG. As can be seen from the figure, it was found that the detection ability of the example was higher than that of the comparative example. It should be noted that there is no unit in the detection capability shown on the vertical axis of FIG. 5 because it is a relative comparison.

When the density of the detection ring for the torque sensor of the embodiment was measured, it was equal to the true density of the material. In contrast, the comparative example had a density lower than the true density of the material. Next, a detection ring for a torque sensor was manufactured by using a similar forging method and a forging apparatus while changing the material as shown in Table 2, and observed.

[0025]

[Table 2]

With this material as well, a detection ring for a torque sensor without any loss of projections was reasonably manufactured by cold forging. Further, the detection ability was able to be improved similarly to the above. Although the embodiments have been described above, the present invention is not limited to these. For example, the method and apparatus of the present invention may be applied to the manufacture of a clutch part, or a crown-shaped part made of a material other than electromagnetic stainless steel. May be applied, and may take any form within the scope of the gist.

[0027]

According to the forging method and the forging apparatus of the present invention, it is possible to mass-produce the inexpensive and high-detection torque sensor, and to improve the production yield. According to the forging method and the forging apparatus of the present invention, not only the torque sensor detection ring,
Various crown-shaped parts can be manufactured easily and with good yield, and the life of the apparatus can be extended.

[Brief description of the drawings]

FIG. 1 shows a detection ring for a torque sensor according to an embodiment;
(A) is a plan view and (b) is an XX cross-sectional view thereof.

FIG. 2 is an explanatory view showing a forging method according to an embodiment.

FIG. 3 is a configuration diagram of a main part of a forging device according to an embodiment.

FIG. 4 shows a punch used in the forging device of the embodiment,
(A) is a plan view, (b) is a front view thereof, (c) is an AA sectional view, (d) is a BB sectional view, and (e) is a C arrow view.

FIG. 5 is a graph comparing the performance of an example and a comparative example.

FIG. 6 is a perspective view of a main part of a torque sensor according to the embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Detection ring, 3 ... Cylindrical body, 5 ... Projection, 1
1 ···················································
..Bottom, 15 extra meat, 20 ... punch, 21 ...
・ Unevenness, 23 ・ ・ ・ Main body, 25 ・ ・ ・ Step, 30 ・ ・ ・
Dice, W ... Material blank.

──────────────────────────────────────────────────続 き Continued on the front page (56) References JP-A-3-94949 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B21K 21/12 B21J 13/02 G01L 3 / Ten

Claims (2)

(57) [Claims] 1. A method for cold forging a crown-shaped part having a projection extending in an axial direction at an end of a ring, wherein a portion corresponding to the projection of the crown is directly formed on a blank material in a first forging step. And a forging method for a crown-shaped part, wherein in the first forging step, forging is performed while generating extra thickness at the outer peripheral portion of the crown projection. 2. An apparatus for cold forging a crown-shaped part having a projection extending in an axial direction at an end of a ring, comprising: a punch having projections and depressions for forming the projection; and a die fitted to the punch. Wherein the punch and the die are formed with a gap at the time of fitting such that the concave and convex portions of the punch are loosely fitted to the die, and the forging of a crown-shaped part is performed. apparatus.