JPH07256387A - Method and device for forging detecting ring and coronary parts for torque sensor - Google Patents

Abstract

PURPOSE:To provide a torque sensor detecting ring that is inexpensive and high in detecting capacity. CONSTITUTION:On a 13 Cr electromagnetic stainless steel blank W, the projecting part 11 of a crown is directly formed in a first forging process (upsetting); a cylindrical part 12 is formed in a second forging process (backward extrusion); and the bottom 13 of a ring body is punched out in a third forging process (punching. These processes are performed in cold state. During these processes, forging is performed while an excess thickness 15 is produced in the projecting part 11 of the crown in the first process. This excess thickness 15 is removed at the time of cutting as a finish working on the surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a detection ring for a torque sensor, a method for forging a coronal part and a forging apparatus suitable for manufacturing the same.

[0002]

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

The detection rings 105 to 107 have a complicated shape having a large number of crown-shaped projections. Therefore, conventionally, the detection rings 105 to 10 for these torque sensors are used.
7, the powder of electromagnetic stainless steel is compacted and sintered,
Finally, the method of cutting and finishing the surface was used.

However, there is a problem that the manufacturing by sintering requires a lot of man-hours. Further, with the recent breakthrough in electronic control technology, there is a demand to further improve the detection accuracy of the torque sensor. However, conventional products have a limit in detection capability, and a component having higher detection capability has been desired.

Therefore, a first object of the present invention is to provide a detection ring for a torque sensor which is inexpensive and has a high detection capability, and further to provide a forging method and a forging apparatus suitable for manufacturing the detection ring. With the goal.

[0006]

A torque sensor detection ring according to the present invention, which has been made to achieve the first object, has a projection extending in the axial direction at the end of the ring, and has a shaft to be detected. A detection ring for a torque sensor fitted externally,
The forging is characterized in that the density ratio of the material to the true density is substantially 1.

According to this torque sensor detection ring,
Since it is forged, there is no increase in man-hours such as sintering and cost increase due to equipment cost, and it is suitable for mass production. Further, according to the torque sensor detection ring of the present invention, since the density ratio is substantially 1 with respect to the true density of the material, the magnetic characteristics are the same as those of the material. Therefore, the ability of the material can be fully exerted.

The method for forging a coronal part of the present invention, which has been made to achieve the second object, is a method for cold forging a coronal part having a projection extending in the axial direction at the end of the ring. In the first blanking step, a portion corresponding to the protrusion of the crown is directly formed on the blank material, and in the first forging step, forging is performed while forming a surplus in the portion of the crown protrusion. To do.

Here, in general, when forging a part having a part having a complicated shape, the body part is formed first and the part having a complicated shape is formed later in the first step. The method of doing is adopted. Also, in such a general forging method, the punch and die are closely attached so that there is no excess thickness.
A device designed to mate is used. Therefore,
In explaining the operation of the forging method of the present invention, assuming a method of forging a coronal part by applying this general forging method,
This will be described in comparison with this.

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

[Meaning and Function of Performing Forging While Producing Extra Thickness] According to the forging method of the present invention, the crown portion is forged while actively producing extra thickness in the first forging step. To do. By creating excess meat, the flow of meat when forging a complicated shape is made smooth. That is, in a general forging method, which is premised on that a surplus thickness is not generated when a complicated shape is suddenly formed, the meat does not sufficiently flow into the cavity formed by the punch and the die, and for example, the projection of the crown is not formed. It is easy to lose part of it. In order to eliminate this, it is necessary to devise measures such as increasing the forging load, which also puts a burden on punches and dies. On the other hand, the configuration adopted in the forging method of the present invention to forge while positively producing a surplus can form a complex-shaped part without a missing portion without increasing the forging load. .

Thus, according to the forging method of the present invention,
By adopting both of the above two characteristic configurations, it is possible to easily and reliably form a crown portion having a complicated shape before work hardening occurs. Even if this is before the work hardening, if the crown portion is forged by a method that does not cause excess thickness, there is a possibility that the portion where the swelling of the meat is insufficient is generated.

By the way, the surplus thickness thus generated may be removed by cutting in order to obtain dimensional accuracy in the finishing process. This finishing step is necessary even for 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. Needless to say, the forging method of the present invention is suitable for manufacturing a torque sensor detection ring as intended by the present invention, but the present invention is not limited to this, and a clutch component to be engaged in a coronal meshing engagement. It is also possible to apply to the manufacture of. In addition, it can be applied to the manufacture of various coronal parts.

On the other hand, the apparatus for forging a crown-shaped part of the present invention, which has been made to achieve the second object, is an apparatus for cold forging a crown-shaped part having a projection extending in the axial direction at the end of the ring. A punch having irregularities for forming the protrusions and a die fitted to the punch, and the punch and the die are configured such that the irregular portions of the punch are loosely fitted to the die. The part is characterized in that a gap is formed at the time of fitting.

According to this forging device, when the crown portion is forged, the gap promotes the escape of meat. As a result, a surplus is generated, which may be removed by cutting during the final finishing. By using the forging device of the present invention in the first step of forging, the forging method of the present invention can be easily carried out.

The forging apparatus of the present invention is not limited to the forging method of the present invention, and is used for forging the crown portion even when the procedure of forming the crown portion in the second and subsequent steps is adopted. It goes without saying that it can be used as a device. Even if the material is work-hardened, the smooth relief of the meat can suppress the increase in the forging load, and even when used in such a method, the punch life can be extended.

[0017]

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

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

[0019]

[Table 1]

As forging, as shown in FIG.
On the other hand, in the first forging step (upset), the protrusion portion 11 of the crown is directly formed, in the second forging step (rear extrusion), the cylindrical body portion 12 is formed, and in the third forging step ( Remove the bottom 13 of the ring body by punching. In the meantime, in the first step, as shown in the figure, forging is performed while forming a surplus thickness 15 on the projection portion 11 of the crown. Figure 2
(D) is not yet completed, and after that, the surplus thickness 15 is cut off and cutting is performed as a surface finishing process to obtain a finished product.

Next, in the first forging step, as shown in FIG. 3, a forging including a punch 20 having irregularities 21 for forming projections of a crown and a die 30 fitted to the punch 20. Use the device. Here, the punch 20 is
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 concave and convex portion 21 so as to enter the inside by about 1 mm. Therefore, when the punch 20 is installed in the die 30, the step 25 becomes a gap, and the meat of the material easily escapes there. That is, this punch 20
Also, the die 30 can form a crown portion while inducing meat escape during upsetting and positively generating the extra thickness 15.

By using the punch 20 and the die 30, in the first forging step, the meat of the blank blank W is firmly raised in the concave portions of the irregularities 21 of the punch 20, and the portion 11 corresponding to the protrusion of the crown is seriously damaged. No part occurred. It was also found that the punch 20 and the die 30 can withstand mass production without being subjected to an excessive forging load.

Next, a detection ring for a torque sensor of a comparative example was manufactured by pulverizing the above material, compacting this material and sintering it. Then, the detection abilities of the detection rings of these Examples and Comparative Examples were compared. In comparing the detection capabilities, the two rings were set to various gaps and the magnetic characteristics were measured. The result is shown in FIG. As can be seen from the figure, it was found that the example has a higher detection ability than the comparative example. Note that the detection capability shown on the vertical axis of FIG. 5 has no unit because it is a relative comparison.

Further, when the density of the torque sensor detection ring of the example was measured, it was equal to the true density of the material. On the other hand, the density of the comparative example was smaller than the true density of the material. Next, as shown in Table 2, the material was changed, and the torque sensor detection ring was manufactured by using the same forging method and forging apparatus.

[0025]

[Table 2]

With this material as well, it was possible to manufacture the torque sensor detection ring without any loss of protrusions by cold forging. Further, its detection ability could be improved in the same manner as 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 clutch parts, or a coronal part made of a material other than electromagnetic stainless steel. The present invention may be applied to the production of any of the above, and any embodiment can be adopted within the scope of the gist.

[0027]

According to the torque sensor detection ring of the present invention, it is possible to provide a torque sensor which is inexpensive and has high detection capability. Further, according to the forging method and the forging device of the present invention, it is possible to mass-produce the above-mentioned inexpensive torque sensor having a high detection capability, and to improve the yield in manufacturing. According to the forging method and the forging device of the present invention, not only the detection ring for the torque sensor but also various coronal parts can be easily manufactured with a high yield, and the life of the device can be extended.

[Brief description of drawings]

FIG. 1 shows a detection ring for a torque sensor according to an embodiment,
(A) is a top view and (b) is the XX sectional view.

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

FIG. 3 is a main part configuration diagram 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 a sectional view taken along the line AA, (d) is a sectional view taken along the line BB, and (e) is a view taken along the arrow C.

FIG. 5 is a graph comparing the performances of Examples and Comparative Examples.

FIG. 6 is a perspective view of a main part of a torque sensor targeted by the embodiment.

[Explanation of symbols]

1 ... Detection ring, 3 ... Cylindrical body, 5 ... Protrusion, 1
1 ... Crown projection, 12 ... Cylindrical part, 13 ...
..Bottom, 15 ... excess, 20 ... punch, 21 ...
・ Roughness, 23 ... Main body, 25 ... Step, 30 ...
Dice, W ... Material blank.

Continuation of front page (72) Inventor Kazushige Hikosaka 2481 Ono, Hamakita City, Shizuoka Prefecture

Claims (3)

[Claims] 1. A detection ring for a torque sensor, which has a protrusion extending in the axial direction at the end of the ring and is fitted onto the shaft to be detected, wherein the density ratio of the material to the true density is substantially 1. A detection ring for a forged torque sensor, which is characterized in that 2. A method for cold forging a crown-shaped part having a projection extending in the axial direction at the end of a ring, wherein a portion corresponding to the projection of the crown in the first forging step is directly formed on a blank material. And in the first forging step, the forging method for the crown-shaped component is characterized in that the forging is carried out while producing a surplus in the projection portion of the crown. 3. A device for cold forging a crown-shaped part having a projection extending in the axial direction at the end of a ring, the punch having irregularities for forming the projection, and a die fitted to the punch. The punch and die are forged coronal parts characterized in that a clearance at the time of fitting is formed in the punch and die so that the concave and convex portions of the punch are loosely fitted in the die. apparatus.