JP5042957B2 - Tapered roller manufacturing method, tapered roller and tapered roller bearing - Google Patents

Description

  The present invention relates to a method of manufacturing a tapered roller for a tapered roller bearing used in automobiles, machine tools, and the like, a tapered roller manufactured by the manufacturing method, and a tapered roller bearing using the tapered roller.

  As a tapered roller bearing used in automobiles, machine tools, etc., a roller that is arranged so as to be able to roll between an outer ring and an inner ring, a tapered roller whose outer peripheral surface has a reduced diameter (or increased diameter) in the axial direction (for example, Patent Document 1). These axial rollers reduced in diameter in the axial direction are generally forged by a die apparatus having a die having a reduced diameter inner diameter shape and a punch or the like provided so as to be close to and away from the die. .

  Specifically, as shown in FIG. 7, a cylindrical roller material 100 is loaded into a die inner diameter shape 101 a having a diameter reduced to a tapered shape of a fixed mold 101. Then, as shown in FIG. 8, the movable mold 102 is lowered to press the upper end of the roller material 100, and the roller material 100 is press-fitted into the die inner diameter shape 101a. When the roller material 100 is press-fitted into the die inner diameter shape 101a, the outer peripheral surface of the roller material 100 is subjected to diameter-reducing plastic processing in a tapered shape. Further, at this time, in the lower end surface of the roller material 100, the peripheral portion near the outer periphery plastically flows downward, thereby forming a concave curved recess 100a in the central portion.

  As shown in FIG. 9, the roller material 100 is further press-fitted into the die inner diameter shape 101a, and the lower end of the roller material 100 is brought into contact with the bottom of the die inner diameter shape 101a. The depression 100a remains on the small end surface 100b at the lower end of the roller material 100 thus forged.

  The movable mold is raised and separated from the fixed mold, and the upper part of the inner diameter shape of the die is opened. Then, as shown in FIG. 10, the knockout pin 103 provided on the fixed mold 101 is raised, and the roller material 100 is pushed out from the die inner diameter shape 101a.

FIG. 11 shows a grinding device for grinding a forged roller material. The grinding apparatus 104 includes a rotatable grindstone 105, an outer diameter restraining jig 106, a reference jig 107, and the like. The outer diameter restraining jig 106 is fixed to the outer peripheral surface of the forged roller material 100, and the reference jig 107 is brought into contact with the recess 100a formed in the small end surface 100b of the roller material 100. As shown by a two-dot chain line in FIG. 11, the large end surface 100 c of the roller material 100 is brought close to the rotating grindstone 105 and ground. By grinding the large end face 100c in this way, the axial length of the roller material 100 is adjusted to a predetermined length with reference to the contact position between the reference jig 107 and the recess 100a.
JP 2004-293698 A

  However, as shown in FIG. 9, the axial dimension X <b> 1 (depth) of the recess 100 a formed in the small end surface 100 b of the roller material 100 varies for each roller material 100. As a result, the reference position (the contact position between the reference jig 107 and the recess 100a) when grinding the roller material 100 also varies, and the axial length cannot be adjusted accurately.

  Therefore, in view of such circumstances, the present invention provides a tapered roller manufacturing method capable of accurately finishing the length of the tapered roller in the axial direction, a tapered roller manufactured by the manufacturing method, and a tapered roller using the tapered roller. A roller bearing is to be provided.

  According to the first aspect of the present invention, a cylindrical roller material loaded in a reduced die inner diameter shape of a fixed mold is pressed with a movable mold, and the roller material is press-fitted into the die inner diameter shape. A step of reducing the diameter while pressing the small end surface of the reduced diameter roller material against a convex portion disposed on the bottom of the inner diameter of the die to form a concave portion on the small end surface; A step of taking out the material for the die from the inside shape of the die, a reference jig is brought into contact with the concave portion of the taken out roller material, and a large end surface opposite to the small end surface of the roller material is ground. And a method of manufacturing a tapered roller having a step of adjusting the length of the roller material in the axial direction to a predetermined length based on the reference jig and the contact position of the recess.

  Since the axial dimension from the axial end of the small end surface of the roller material to the bottom of the recess is set to a predetermined dimension, the axial reference position (reference jig and recess in grinding) is set. Is also set to a predetermined position. This makes it possible to accurately adjust the axial length of the roller material.

  According to a second aspect of the present invention, in the method for manufacturing the tapered roller according to the first aspect, the convex portion is constituted by a flat surface portion at a tip perpendicular to the axial direction and a tapered peripheral surface portion reduced in diameter toward the tip. It is.

  According to a third aspect of the present invention, the convex portion is formed in a conical shape.

  According to a fourth aspect of the present invention, in the method for manufacturing the tapered roller according to the first aspect, the convex portion is formed into a spherical shape.

  According to a fifth aspect of the present invention, in the method for manufacturing the tapered roller according to the first aspect, the convex portion is composed of a spherical portion at the tip and a straight circumferential surface portion arranged in parallel to the axial direction. is there.

  As described in claims 2 to 5, the shape of the convex portion can be changed.

  A sixth aspect of the present invention is the method of manufacturing a tapered roller according to any one of the first to fifth aspects, wherein the convex portion constitutes a bottom portion of the die inner diameter shape and the roller material is formed into a die inner diameter shape. It is arrange | positioned at the front-end | tip of the extrusion member extruded from inside.

  The present invention is applicable to a mold apparatus provided with an extrusion member.

According to a seventh aspect of the present invention, in the method for manufacturing the tapered roller according to the sixth aspect, the yield stress of the roller material is σy, the yield stress of the extruded member is σk, the diameter of the tip end surface of the convex portion is Ds, When the diameter of the small end surface of the roller material is De, and the difference between the radius of the small end surface of the roller material and the radius of the pushing member is t, a formula of Ds ² ≦ σk (De−2t) ² / σy is obtained. Manufacture to meet.

  Thereby, a recessed part can be reliably formed in the small end surface of the raw material for rollers.

  The invention of claim 8 is a tapered roller formed by the method of manufacturing a tapered roller according to any one of claims 1 to 7.

  Thereby, the tapered roller which finished the length of the axial direction with high precision can be obtained.

  A ninth aspect of the present invention is a tapered roller bearing in which the tapered roller according to the eighth aspect is interposed between an outer ring and an inner ring so as to allow rolling.

  A tapered roller whose axial length is finished with high accuracy can be applied to a tapered roller bearing.

  According to the method for manufacturing a tapered roller of the present invention, the length of the tapered roller in the axial direction can be finished with high accuracy, leading to quality improvement. Specifically, the tapered roller manufactured by the method of the present invention has a variation in length in the axial direction as compared with the tapered roller manufactured by the conventional method of grinding with reference to a recess formed in the small end surface of the tapered roller. Was reduced to about 1/5.

  FIG. 1 is a longitudinal sectional view of a mold apparatus 1 used in the method for manufacturing a tapered roller of the present invention, and shows a state in which a tapered roller 2 is forged. Hereinafter, the configuration of the mold apparatus 1 will be described with reference to FIG. The mold apparatus 1 has a movable mold 3 that mainly forms a large end surface of the tapered roller 2 and a fixed mold 4 that mainly forms a small end surface and an outer peripheral surface of the tapered roller. The movable mold 3 is attached to a mold apparatus main body (not shown) so as to be movable up and down. In this embodiment, the movable mold 3 has a punch pin 6 disposed on the axis of the punch 5.

  The fixed mold 4 includes a die 7 and a knockout pin 8 (extrusion member) assembled to the die 7 so as to be movable in the axial direction. The die 7 is formed with a forming hole 7a having a diameter reduced in a tapered shape toward the lower side of the drawing. A knockout pin 8 is inserted into an insertion hole 7b that communicates downward from the lower end of the figure of the molding hole 7a so as to advance and retreat in the axial direction. As shown in the figure, a die inner diameter shape 9 for molding the tapered roller 2 is defined by a combination of a molding hole 7 a of the die 7 and a tip end surface (upper end surface in the drawing) of the knockout pin 8.

  A convex portion 8 a is disposed at the tip of the knockout pin 8. As shown in FIG. 2A in which the tip of the knockout pin 8 is enlarged, the convex portion 8a is composed of a flat portion 81 at the tip orthogonal to the axial direction and a tapered peripheral surface portion 82 that is reduced in diameter toward the tip. Has been.

  (B) to (d) of FIG. 2 show modifications of the convex portion 8a. The convex portion 8a shown in (b) is formed in a conical shape, and the convex portion 8a shown in (c) is formed in a spherical shape. Moreover, the convex part 8a shown to (d) is comprised by the spherical part 83 of a front-end | tip, and the straight-shaped peripheral surface part 84 arrange | positioned in parallel with the axial direction. In addition, the shape of the convex part 8a may be other shapes.

Hereinafter, the manufacturing method of the tapered roller of this invention is demonstrated.
As shown in FIG. 3, a roller material 20 obtained by cutting a cylindrical material such as steel into a predetermined length is loaded into a die inner diameter shape 9 of the fixed mold 4. A movable mold 3 (not shown) is disposed above the fixed mold 4.

  As shown in FIG. 4, the movable mold 3 is lowered to press the upper end of the roller material 20, and the roller material 20 is press-fitted into the die inner diameter shape 9. When the roller material 20 is press-fitted into the inner diameter shape 9 of the die, the outer peripheral surface of the roller material 20 is subjected to plastic processing with a reduced diameter in a tapered shape. Further, at this time, in the lower end surface of the roller material 20, the concave portion 20 a having a concave curved surface is formed in the central portion by plastic flow of the vicinity of the outer periphery downward.

  Further, when the roller material 20 is press-fitted downward, the recess 20a of the roller material 20 comes into contact with the convex portion 8a of the knockout pin 8. And the convex part 8a is pressed by the hollow 20a, and the recessed part 20b is formed in the hollow 20a (refer FIG. 1). The axial dimension X2 (depth) from the axial endmost part (near the outer periphery) on the small end surface of the roller material 20 to the bottom of the recess 20b is formed to a predetermined dimension.

  The movable mold 3 is raised and separated from the fixed mold 4, and the upper portion of the die inner diameter shape 9 is opened. Then, as shown in FIG. 5, the knockout pin 8 is raised to push out the roller material 20 from the inside diameter shape 9 of the die.

  Next, in order to adjust the axial length of the forged roller material 20 to a predetermined length, the large end surface of the roller material 20 is ground. As shown in FIG. 6, first, the outer diameter restraining jig 10 is fixed to the outer peripheral surface of the roller material 20, and the reference jig 11 is brought into contact with the recess 20b (the bottom thereof).

  Then, with the roller material 20 held by the outer diameter restraining jig 10 and the reference jig 11, the large end surface of the roller material 20 is brought close to a rotating grindstone (not shown) and ground. The axial length L (see FIG. 1) of the roller material 20 is adjusted based on the contact position of the reference jig 11 and the recess 20b. As described above, the axial dimension X2 (see FIG. 1) from the axial end of the small end surface of the roller material 20 to the bottom of the recess 20b is set to a predetermined dimension. The reference position in the axial direction is also set to a predetermined position. Thereby, it is possible to accurately adjust the length L in the axial direction of the roller material (conical roller).

  In FIG. 1, when the convex portion 8a is pressed against the small end surface of the roller material 20, the stress on the small end surface is σy, and the diameter of the tip end surface of the convex portion 8a is Ds. The load F applied to the small end face of the material 20 is expressed as the following mathematical formula (1).

  Further, the stress on the knockout pin 8 when the convex portion 8a is pressed against the small end surface of the roller material 20 is σk, the diameter of the small end surface of the roller material 20 is De, the radius of the small end surface of the roller material 20 is When the difference in the radius of the knockout pin 8 is t, the load P applied to the knockout pin 8 at this time is expressed as the following formula (2).

  Here, when the stress σy is the yield stress of the small end face of the roller material 20, and the stress σk is the yield stress of the knockout pin 8, F and P in the above formulas (1) and (2) satisfy the relationship of F ≦ P. If there is, the concave portion 20b can be formed by plastically deforming the small end face of the roller material 20 by pressing the convex portion 8a. In other words, in order to reliably form the recess 20b, it is necessary to satisfy the following formula (3) obtained by substituting the formulas (1) and (2) into the formula of F ≦ P.

  For example, when σk = 2100 MPa, σy = 700 MPa, De = 10 mm, and t = 1.5 mm, when these are substituted into the above equation (3), Ds ≦ 4.58. Therefore, if the diameter of the convex portion 8a is 4.58 mm or less, the concave portion 20b can be formed.

  The tapered roller manufacturing method of the present invention has been described by taking the case of manufacturing a tapered roller as an example. In order to extend the life of the mold apparatus used in the present invention, the above-described forging may be performed after preforming the cylindrical roller material once or a plurality of times.

It is a longitudinal cross-sectional view of the metal mold apparatus used for the manufacturing method of the tapered roller of this invention. (A) is an enlarged view which shows the convex part of the knockout pin of the said metal mold apparatus, (b) (c) (d) is an enlarged view which shows the modification of the said convex part. It is a figure explaining the manufacturing process of the tapered roller of this invention. It is a figure explaining the manufacturing process of the tapered roller of this invention. It is a figure explaining the manufacturing process of the tapered roller of this invention. It is a figure explaining the manufacturing process of the tapered roller of this invention. It is a figure explaining the manufacturing process of the conventional tapered roller. It is a figure explaining the manufacturing process of the conventional tapered roller. It is a figure explaining the manufacturing process of the conventional tapered roller. It is a figure explaining the manufacturing process of the conventional tapered roller. It is a figure explaining the manufacturing process of the conventional tapered roller.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mold apparatus 2 Tapered roller 3 Movable mold 4 Fixed mold 8 Knockout pin (extrusion member)
8a Convex portion 9 Die inner diameter shape 11 Reference jig 20 Roller material 20a Depression 20b Recessed portion 81 Flat portion 82 Tapered peripheral surface portion 83 Spherical surface portion 84 Straight peripheral surface portion L Length

Claims (9)

A step of pressing a cylindrical roller material loaded in a reduced die inner diameter shape of a fixed mold with a movable mold and pressing the roller material into the die inner diameter shape to reduce the diameter; and
Pressing the small end surface of the roller material having a reduced diameter against a convex portion disposed on the bottom of the die inner diameter shape to form a concave portion on the small end surface;
A step of taking out the roller material from the inside shape of the die;
A reference jig is brought into contact with the recessed portion of the roller material taken out, and the large end surface opposite to the small end surface of the roller material is ground to process the axial length of the roller material, A method of manufacturing a tapered roller, comprising the step of adjusting the reference jig and a predetermined length based on a contact position of the recess.   2. The method for manufacturing a tapered roller according to claim 1, wherein the convex portion includes a flat portion at a tip perpendicular to the axial direction and a tapered peripheral surface portion reduced in diameter toward the tip.   The method for manufacturing a tapered roller according to claim 1, wherein the convex portion is formed in a conical shape.   The method for manufacturing a tapered roller according to claim 1, wherein the convex portion is formed into a spherical shape.   2. The method for manufacturing a tapered roller according to claim 1, wherein the convex portion is constituted by a spherical surface portion at a tip end and a straight circumferential surface portion disposed in parallel with the axial direction.   The said convex part is arrange | positioned in the front-end | tip of the extrusion member which comprises the bottom part of the said die internal diameter shape, and extrudes the said raw material for rollers from the inside of a die internal diameter shape, It is any one of Claim 1 to 5 characterized by the above-mentioned. The manufacturing method of the tapered roller of description. The yield stress of the roller material is σy, the yield stress of the extruded member is σk, the diameter of the tip end surface of the convex portion is Ds, the diameter of the small end surface of the roller material is De, and the small end surface of the roller material is The method for manufacturing a tapered roller according to claim 6, wherein a formula of Ds ² ≦ σk (De−2t) ² / σy is satisfied, where t is a difference between the radius and the radius of the extruded member.   A tapered roller formed by the method of manufacturing a tapered roller according to any one of claims 1 to 7.   A tapered roller bearing comprising the tapered roller according to claim 8 interposed between an outer ring and an inner ring so as to be able to roll.

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