JP2019007046A - Heat treatment method of annular member - Google Patents

Abstract

An object of the present invention is to suppress deviation from the shape of a finished product when an annular member having a cross-sectional shape whose wall thickness gradually changes from one axial direction to the other, such as a raceway of a tapered roller bearing. , Reduce the load of the correction process after heat treatment. A heat treatment method for an annular member made of steel and having an outer peripheral surface whose thickness in the axial direction becomes thinner from one end to the other end in an axial direction, the amount corresponding to the amount of deformation caused by the heat treatment. An annular member having a large diameter on the thick side and a small diameter on the thin side is used as a starting member. [Selection] Figure 4

Description

  The present invention relates to a heat treatment method for an annular member having a cross-sectional shape whose wall thickness gradually changes from one end portion in the axial direction to the other end portion, such as an inner ring and an outer ring of a tapered roller bearing.

  FIG. 1 is a cross-sectional view showing a completed shape of a tapered roller bearing (however, a cage is not shown). The inner ring 1 has a cylindrical shape with an inner peripheral surface 2 having a radius Ri, and an inner ring raceway surface 5 is formed on the outer peripheral surface 3 between a large-diameter side flange 4a and a small-diameter side flange 4b. This inner ring raceway surface 5 is one surface 10 in the axial direction of the inner ring 1 (the upper end in the drawing, hereinafter referred to as “upper end surface 10”) to the other surface 20 (the lower end in the drawing, hereinafter “lower” It is an inclined surface in which the wall thickness gradually decreases toward the end face 20 ". Further, the large-diameter side jaw 4a is thick, and the small-diameter side jaw 4b is thin.

  On the other hand, the outer ring 100 has an outer ring raceway surface 105 formed of an inclined surface whose outer peripheral surface 103 has a cylindrical shape with a radius Ro, and whose inner peripheral surface gradually increases in thickness from the upper end surface 110 toward the lower end surface 120. .

  A tapered roller 50 is disposed between the inner ring raceway surface 5 of the inner ring 1 and the outer ring raceway surface 105 of the outer ring 100, and is held by a cage (not shown) to form a tapered roller bearing.

  By the way, in the tapered roller bearing, for the purpose of improving wear resistance and the like, generally, the hardness of the inner ring raceway surface 5 and the outer ring raceway surface 105 is increased by heat treatment. However, when the starting member is deformed by this heat treatment and the starting member processed into the shape shown in FIG. 1 according to the completed shape is used, the inner peripheral surface 2 of the inner ring 1 is lowered from the upper end surface 10 as shown in FIG. A cross-sectional shape inclined so as to gradually increase in diameter toward the end face 20 is exhibited. Further, the upper end surface 10 becomes an inclined surface rising from the edge of the inner peripheral surface 2 toward the outer peripheral surface 3, and the lower end surface 20 is also an inclined surface rising from the end edge of the inner peripheral surface 2 toward the outer peripheral surface 3. It becomes. 1 is the position of the upper end face 10 in the finished product shown in FIG. 1, and the alternate long and short dash line B indicates the position of the lower end face 20. That is, as a whole, it is deformed into a shape that is inclined upward toward the outer peripheral surface side.

  Further, when the outer ring 100 is also made of a starting member that is processed in accordance with the completed shape shown in FIG. 1, the outer peripheral surface 103 gradually increases in diameter from the upper end surface 110 toward the lower end surface 120 as shown in FIG. 3. In this way, the cross-sectional shape is inclined. Further, the upper end surface 110 is an inclined surface that descends from the edge of the outer ring raceway surface 105 toward the outer peripheral surface 103, and the lower end surface 120 is an inclined surface that descends from the edge of the outer ring raceway surface 105 toward the outer peripheral surface 103. . The alternate long and short dash line A or B is the same as in FIG. That is, as a whole, it is deformed into a shape inclined downward toward the outer peripheral surface side.

  For this reason, a straightening process is required for processing into a finished shape after the heat treatment, but as shown in FIGS. 2 and 3, the processed portion is substantially a base in which the thickness gradually changes from one to the other over the entire axial direction. The cross-sectional shape of the shape, the upper end surface and the lower end surface are also inclined. For this reason, the machining cost changes over the entire axial direction, which takes time and effort. From such a background, the present applicant has proposed in Patent Document 1 that the inner ring and the outer ring after heat treatment are pressed into a mold to be plastically deformed and corrected.

Japanese Patent No. 3817764

  The deformation due to the heat treatment as described above becomes more prominent as the diameter of the bearing becomes larger. With the correction method of Patent Document 1, the correction device becomes larger and press-fitting into the mold becomes difficult.

  The present invention has been made in view of such a situation, and heat-treated an annular member having a cross-sectional shape whose wall thickness gradually changes from one to the other in the axial direction, like a tapered ring of a tapered roller bearing. An object is to provide a new method for suppressing the deviation from the shape of the finished product.

In order to solve the above problems, the present invention provides the following heat treatment method.
(1) A heat treatment method for an annular member made of steel and having an outer peripheral surface whose thickness in the axial direction becomes thinner from one end to the other end in the axial direction,
In an amount commensurate with the amount of deformation due to heat treatment,
A heat treatment method for an annular member, characterized in that heat treatment is performed using an annular member having a large diameter on the thick side and a small diameter on the thin side as a starting member.
(2) The annular member heat treatment method according to (1), wherein the annular member is an inner ring of a tapered roller bearing with or without a flange.
(3) The inclination angle of the inner ring raceway surface of the starting member is made larger on the thin side than on the thick side with respect to the inclination angle of the inner ring raceway surface of the finished product obtained by heat treatment. (2) The heat processing method of the annular member of description.
(4) The heat treatment method for an annular member according to any one of (1) to (3), wherein an inner diameter of the annular member is 1000 mm or more.
(5) A heat treatment method for an annular member made of steel and having an inner peripheral surface whose thickness in the axial direction is increased from one end to the other end in the axial direction,
In an amount commensurate with the amount of deformation due to heat treatment,
A heat treatment method for an annular member, characterized in that heat treatment is performed using an annular member having a large diameter on the thick side and a small diameter on the thin side as a starting member.
(6) The heat treatment method for an annular member according to (5), wherein the annular member is an outer ring of a tapered roller bearing with or without a flange.
(7) The inclination angle of the outer ring raceway surface of the starting member is made smaller on the thin side than on the thick side with respect to the inclination angle of the outer ring raceway surface of the finished product obtained by heat treatment. (6) The heat processing method of the annular member of description.
(8) The heat treatment method for an annular member according to any one of (1) to (7), wherein the heat treatment is high-frequency heat treatment.

  According to the present invention, since the heat treatment is performed using the starting member inclined in the direction opposite to the deformation due to the heat treatment, the shape of the annular member after the heat treatment is close to the shape of the finished product, and the processing in the correction process after the heat treatment is performed. Loads such as amount, processing time, and labor can be greatly reduced, and in some cases, the correction process can be omitted, and the manufacturing cost can be greatly reduced. In particular, it is effective in application to a large-diameter annular member.

It is sectional drawing which shows the completion shape of a tapered roller bearing. It is sectional drawing which shows the deformation | transformation state after heat processing when using the inner ring | wheel of the shape shown in FIG. 1 as a starting member. It is sectional drawing which shows the deformation | transformation state after heat processing when using the outer ring | wheel of the shape shown in FIG. 1 as a starting member. It is sectional drawing which shows the starting member of the inner ring | wheel shown in FIG. It is sectional drawing which shows the starting member of the outer ring | wheel shown in FIG.

  The present invention will be described in detail below with reference to the drawings. In this embodiment, the inner ring and the outer ring of the tapered roller bearing shown in FIG. 1 will be described as an example of the annular member.

  As described above, the inner ring 1 of the tapered roller bearing shown in FIG. 1 undergoes the deformation shown in FIG. 2 after the heat treatment. That is, the inner peripheral surface 2 of the inner ring 1 gradually increases in diameter from the upper end surface 10 toward the lower end surface 20, and both the upper end surface 10 and the lower end surface 20 extend from the edge of the inner peripheral surface 2 toward the outer peripheral surface. To form an inclined surface that rises.

  Therefore, in the present invention, in consideration of such deformation, heat treatment is performed using a starting member having a cross-sectional shape shown in FIG. The inner peripheral surface 2 is gradually made smaller in diameter from the upper end surface 10 toward the lower end surface 20 so as to have an inclined surface opposite to that in FIG. The upper end surface 10 and the lower end surface 20 are inclined surfaces that descend from the inner peripheral surface side to the outer peripheral surface side. 1 is the position of the upper end surface 10 in the finished product shown in FIG. 1, and the one-dot chain line B is the position of the lower end surface 20 in the finished product.

  Further, with respect to the inner ring raceway surface 5, the upper end surface side (wall thickness side) is made larger than the other end surface side (thin wall side) with respect to the inclination angle of the finished inner ring raceway surface 5.

  On the other hand, for the outer ring 100 as a starting member, a starting member having a cross-sectional shape inclined in the direction opposite to that in FIG. That is, as shown in FIG. 5, the upper end surface 110 and the lower end surface 120 are inclined surfaces that rise from the inner peripheral surface side to the outer peripheral surface side. In addition, the dashed-dotted lines A and 3 in a figure are the same as that of FIG.

  For the outer ring raceway surface 105, the upper end surface side is made smaller than the other end surface side with respect to the inclination angle of the finished inner ring raceway surface 105.

  Note that the inclination angles of the inner peripheral surface 2, the inner ring raceway surface 5, the outer ring raceway surface 105, the upper end surfaces 10, 110 and the lower end surfaces 20, 120 are actually heat-treated on the finished inner ring 1 and outer ring 100 shown in FIG. And it sets from the degree of deformation of each part as shown in FIG. 2 and FIG.

  In this way, by using the starting members of the inner ring 1 and the outer ring 100 shown in FIGS. 4 and 5 and performing heat treatment, the inner ring 1 and the outer ring 100 obtained after the heat treatment become close to the completed shape, and the load in the correction process Can be greatly reduced. Further, since a correction mold is not used as in Patent Document 1, the inner ring 1 and the outer ring 100 having a large diameter can be easily applied to the inner ring 1 and the outer ring 100 having an inner diameter exceeding 1000 mm. Can respond.

  Although there is no limitation on the heat treatment method, heat treatment can be performed only on the surface layer portion of the treatment surface, deformation can be reduced, large-diameter inner ring 1 or outer ring 100 does not cause an increase in heat treatment apparatus, In view of the fact that it is possible to cope with this, high frequency heat treatment is preferable.

  In the above description, a tapered roller bearing with a hook is illustrated and described. However, a similar starting member is also used in a tapered roller bearing without a hook, that is, a tapered roller bearing using the inner ring 1 without the small-diameter side flange 4b. Thereby, the inner ring | wheel 1 and the outer ring | wheel 100 which are close to completion shapes can be obtained, without performing a correction | amendment operation | work.

  Furthermore, the present invention can be applied not only to the tapered roller bearing but also to an annular member having a cross-sectional shape whose wall thickness changes in the axial direction, for example, a ring of an angular ball bearing.

DESCRIPTION OF SYMBOLS 1 Inner ring 2 Inner peripheral surface 3 Outer peripheral surface 4a Large diameter side jaw part 4b Small diameter side jaw part 5 Inner ring raceway surface 10 Upper end surface 20 Lower end surface 50 Tapered roller 100 Outer ring 103 Outer peripheral surface 105 Outer ring raceway surface 110 Upper end surface 120 Lower end surface

Claims (8)

A heat treatment method of an annular member made of steel and having an outer peripheral surface whose thickness in the axial direction becomes thinner from one end to the other end in the axial direction,
In an amount commensurate with the amount of deformation due to heat treatment,
A heat treatment method for an annular member, characterized in that heat treatment is performed using an annular member having a large diameter on the thick side and a small diameter on the thin side as a starting member.   2. The method for heat treatment of an annular member according to claim 1, wherein the annular member is an inner ring of a tapered roller bearing with or without a flange.   The inclination angle of the inner ring raceway surface of the starting member is made larger on the thin side than on the thick side with respect to the inclination angle of the inner ring raceway surface of the finished product obtained by heat treatment. A heat treatment method for an annular member.   The heat treatment method for an annular member according to any one of claims 1 to 3, wherein an inner diameter of the annular member is 1000 mm or more. It is a heat treatment method for an annular member made of steel and having an inner peripheral surface whose thickness in the axial direction is thicker from one end to the other end in the axial direction,
In an amount commensurate with the amount of deformation due to heat treatment,
A heat treatment method for an annular member, characterized in that heat treatment is performed using an annular member having a large diameter on the thick side and a small diameter on the thin side as a starting member.   6. The method for heat treatment of an annular member according to claim 5, wherein the annular member is an outer ring of a tapered roller bearing with or without a flange.   The inclination angle of the outer ring raceway surface of the starting member is smaller on the thin side than on the thick side with respect to the inclination angle of the outer ring raceway surface of the finished product obtained by heat treatment. A heat treatment method for an annular member.   The annular member heat treatment method according to claim 1, wherein the heat treatment is a high-frequency heat treatment.

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