JPH07111208B2 - Hollow roller manufacturing method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing hollow rollers used in planetary roller type power transmission devices, roller bearings and the like.

[0002]

2. Description of the Related Art Conventional hollow rollers of this type are usually hardened for the purpose of making the outer peripheral surface of the rolling contact with the mating member less likely to wear.

However, when the inside of the hollow roller is hardened, when it receives an impact or the like, tensile stress is concentrated on the inner peripheral surface side of the hollow part due to temporary deformation, and the part is easily cracked, which is desirable. It is said that only the outer surface of the hollow roller should be hardened to leave a soft portion inside.

[0004]

By the way, it is difficult to precisely control the carburizing depth during carburizing, and in the case of hollow rollers, carburizing is performed from both the outer peripheral surface and the inner peripheral surface of the hollow portion. Therefore, if the wall thickness is thick, it is possible to leave a soft part inside, but in the case of thin wall bearings such as small roller bearings and hollow rollers used in planetary roller type power transmission devices. , Can not leave a soft part inside.

Therefore, in the prior art, a hollow roller having a large wall thickness is carburized in advance, and then a hardened portion on the inner diameter side is polished to obtain a thin hollow roller in which a soft portion inside is exposed on an inner peripheral surface. Was doing. However, in this case, since the inner diameter polishing process must be performed after the carburizing process, the number of working steps is increased, which is troublesome and the cost is inevitably increased.

Therefore, an object of the present invention is to make it possible to easily and inexpensively manufacture hollow rollers having excellent wear resistance and impact relaxation.

[0007]

DISCLOSURE OF THE INVENTION The present invention is a method for producing a substantially cylindrical hollow roller which is disposed between inner and outer cylindrical members which rotate relative to each other, and which has a substantially cylindrical shape, and which is at least hollow. The inner peripheral side of the part is left unpolished, and the inner peripheral side of the hollow part is covered with another member, and the outer surface excluding the surface covered with the different member is subjected to a curing treatment. An unpolished soft portion is left on the inner peripheral side of the portion so as not to generate tensile stress during rolling motion.

The hardening process may be a carburizing process. Further, the separate member may be a shaft fitted into the hollow portion of the hollow roller, or a carburizing inhibitor adhered to the inner peripheral surface of the hollow roller.

[0009]

In the present invention, the outer surface of the hollow roller can be hardened while leaving the soft portion inside while the inner peripheral side of the hollow roller is not polished. Therefore, the number of man-hours required for work can be reduced as compared with the conventional case.

The manufactured hollow roller is hard to wear because the outer surface thereof is hardened. Further, since the unpolished soft portion is left on the inner peripheral side of the hollow portion of the hollow roller, even if the hollow roller bends and deforms during rolling motion, the soft stress easily absorbs and attenuates the tensile stress accompanying the bending.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the embodiments shown in FIGS. FIG. 1 is a vertical sectional view of a hollow roller according to an embodiment of the present invention. Hollow roller 1 in the example
Is a cylindrical shape made of, for example, bearing steel, and its outer surface (outer peripheral surface 2 and shaft end surface 3) is carburized to form a hardened portion 4 having a predetermined depth. No carburizing treatment is applied to the inner peripheral side of 5 (the inner peripheral surface 6 and the inside), and the soft state remains. In the figure, the cured portion 4 is represented by a spot.

In order to carry out such partial hardening, for example, a carburizing treatment is carried out with a shaft fitted in the hollow portion 5 or with an inner surface 6 of the hollow portion 5 being coated with a carburizing inhibitor. I'll do it. In other words, it is only necessary to cover the part that is not to be carburized with a member that blocks the outside air of carburization. The depth of the hardened portion 4 is controlled by controlling the carburizing depth.
Since the unhardened part is selectively left, it is not necessary to control the carburizing depth very precisely. If it is necessary to improve the surface accuracy of the inner peripheral surface 6, the inner diameter may be reamed. This reaming process is also easier than the conventional inner diameter polishing.

As described in the section of the conventional example, the hollow roller 1 is temporarily deformed when it receives a shock during use, and tensile stress is concentrated on the inner peripheral surface 6 side of the hollow portion 5. However, if a soft portion is left on the inner peripheral side (inner peripheral surface 6 and inside) of the hollow portion 5 as in this embodiment, cracking at an early stage can be prevented. By the way, according to the above method, even if the hollow roller 1 is extremely thin, the soft portion can be left selectively. Therefore, even in the case of such a thin hollow roller 1, the inner peripheral surface 6 of the hollow portion 5 is Can be prevented from breaking at an early stage. Moreover, as compared with the conventional case where the hollow hollow roller 1 having a large thickness is carburized and then the inner diameter is polished to obtain the thin hollow roller 1, the number of working steps can be reduced, which is advantageous in cost.

As shown in FIG. 2, such a hollow roller 1 serves as a planetary roller 7 of a planetary roller type power transmission device.
Further, as shown in FIG. 3, the hollow roller 1 is used as a cylindrical roller 8 of a cylindrical roller bearing. In addition, in FIG. 2, 9 is a fixed ring, 10 is a first rotating shaft which is a sun ring,
1 is a second rotating shaft arranged coaxially with the first rotating shaft 10, 1
2 is a planetary roller 7 formed integrally with the shaft end of the second rotating shaft 11.
A carrier that rotates with the first rotary shaft 9;
And rolling bearings that support the second rotating shaft 10 on the fixed ring 9, respectively. On the other hand, in FIG. 3, 15 is an outer ring, 16 is an inner ring, and 17 is a cage.

The present invention is not limited to the above embodiment. First, although the example in which the hardened portion 4 is formed on the outer peripheral surface 2 and the shaft end surface 3 is given in the embodiment, the hardened portion 4 can be formed only on the outer peripheral surface 2, and
It is also possible to form only a part of the outer peripheral surface 2. Further, although the example of the cylindrical hollow roller 1 is given, the invention can be applied to, for example, a conical hollow roller.

[0016]

According to the present invention, when manufacturing a hollow roller having a structure in which the outer surface is hardened by leaving a soft portion where tensile stress does not occur during rolling motion on the inner peripheral side of the hollow portion, the inner peripheral side of the hollow portion of the hollow roller is manufactured. Since it is not polished, there is no need to perform the polishing treatment after the carburizing treatment as in the conventional example, and the manufacturing labor can be reduced and the manufacturing cost can be reduced.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a hollow roller according to an embodiment of the present invention.

2 is a vertical cross-sectional view of the upper half of a planetary roller power transmission device using the cylindrical roller of FIG.

3 is a longitudinal sectional view of the upper half of a cylindrical roller bearing using the cylindrical roller of FIG.

[Explanation of symbols]

 1 Hollow Roller 2 Outer Surface of Hollow Roller 3 Shaft End Surface of Hollow Roller 4 Hardened Part of Hollow Roller 5 Hollow Part of Hollow Roller

Claims (4)

[Claims] 1. A method for producing a substantially cylindrical hollow roller which is arranged between relatively rotating inner and outer cylindrical members and rolls, wherein at least the inner peripheral side of the hollow roller is in an unpolished state. The hollow portion has an inner peripheral side covered with another member, and a step of performing a hardening treatment on the outer surface excluding the surface covered with the different member, and the hollow portion inner peripheral side has a tensile stress during rolling motion. A method for producing a hollow roller, characterized in that an unpolished soft portion is left so as not to cause the occurrence of 2. The method for manufacturing a hollow roller according to claim 1, wherein the hardening treatment is a carburizing treatment. 3. The method of manufacturing a hollow roller according to claim 1, wherein the separate member is a shaft fitted in the hollow portion of the hollow roller. 4. The carburizing preventive agent applied to the inner peripheral surface of the hollow roller, wherein the separate member is a carburizing inhibitor.
Method for manufacturing hollow rollers.