JP3871842B2 - Molding method for ring-shaped products without seizure defects - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for forming a ring-shaped product such as an outer ring of a bearing race by cold rolling a material ring with a forming roll and a mandrel.
[0002]
[Prior art]
Conventionally, as a cold rolling method for ring-shaped products such as bearing races, a material ring with a black skin by hot forging or a material ring with a black skin obtained by cutting a hot-finished steel pipe is pressed between a forming roll and a mandrel to a predetermined size. Rolled into a ring-shaped product intermediate product by cold rolling processing (hereinafter referred to as “CRF processing”), and then the entire surface is turned with a lathe to be heat-treated and polished, or The entire surface of the black ring material ring was turned with a lathe, then CRF processed, and then heat treated and polished. However, among these methods, the former has a problem in terms of cost, and the latter has a fine crack at the edge of the ball groove in the case of a bearing race outer ring, and a fine surface on the entire surface when the ring inner surface is flat. There are problems such as the occurrence of cracks, and as a solution to these problems, a method has been developed in which the diameter of the mandrel is smaller than the inner diameter of the material ring and the amount of reduction per rotation of the material ring is reduced. However, since the restriction of the material ring by the rolling tool is gradually reduced, the rolling becomes unstable, and the shape accuracy of the rolled ring-shaped product is deteriorated, resulting in a shape defect that becomes an ellipse or a polygon.
[0003]
[Problems to be solved by the invention]
The problem to be solved by the present invention is that in the production of a ring-shaped product by CRF processing, in order to obtain a ring-shaped product having no shape defect, after performing CRF processing and further sizing processing, between the sizing die and the workpiece It is intended to provide a method for preventing the occurrence of seizure flaws on the outer peripheral surface of a ring-shaped product due to seizure occurring in the ring, and for reducing the quality and productivity for correcting the sizing die and preventing the cost increase.
[0004]
[Means for Solving the Problems]
In the invention of claim 1, the means for solving the above-mentioned problems of the present invention is that the material ring 8 is subjected to CRF processing in the middle of the ring-shaped product using the forming roll 1 for processing the outer peripheral surface and the mandrel 7 for processing the inner peripheral surface. In the molding method of the ring-shaped product 20, the ring-shaped product intermediate product 10 is sized by passing it through a sizing die 16 to form the ring-shaped product 20. A plurality of minute ridges 12 are formed on the outer peripheral surface 11 of the ring-shaped product intermediate product 10 after the CRF processing and before the sizing processing by performing the CRF processing using the forming roll 1 included in FIG. The lubricant is moistened between the plurality of minute ridges 12, 12 on the outer peripheral surface 11 of the intermediate product 10 of the ring-shaped product, and the intermediate product 10 of the ring-shaped product is passed through the sizing die 16 of the sizing device. Molding process of seizure flawless ring product 19, characterized in that the ring machining.
[0005]
In the invention of claim 2, the minute concave groove 3 on the molding surface 2 of the molding roll 1 has a width 6 of 0.03 to 0.1 mm and a depth 5 of 0.03 to 0.1 mm. The minute ridges 12 formed on the outer peripheral surface 11 of the intermediate product 10 have a width 13 of 0.03 to 0.1 mm and a height 14 of 0.03 to 0.1 mm, and are adjacent to the plurality of grooves 3. The distance 4 between the groove 3 and the distance 15 between the adjacent ridges 12 of the plurality of ridges 12 is 0.8 to 1.2 mm, respectively. This is a method of forming the ring-shaped product 19 which is not.
[0006]
The ring-shaped product intermediate product as used in the present invention refers to a ring-shaped molded body immediately before sizing by forming a material ring into a predetermined size by CRF processing.
[0007]
Next, in the invention according to claim 2, the width of the concave groove formed on the molding surface of the molding roll is 0.03 to 0.1 mm, the depth is 0.03 to 0.1 mm, and the interval between the concave grooves Is set to 0.8 to 1.2 mm, the width of the protrusion formed on the outer peripheral surface of the ring-shaped product is 0.03 to 0.1 mm, the height is 0.03 to 0.1 mm, The reason for limiting the interval between the stripes to 0.8 to 1.2 mm is that when the width and height of the protrusions formed on the outer peripheral surface of the ring-shaped product are less than 0.03 mm, respectively, it is sufficient when sizing This is because it is not possible to obtain ridges that are high enough to moisten the lubricant, and if they exceed 0.1 mm, it is not easy to finish the outer peripheral surface smoothly by sizing. If the spacing is less than 0.8mm, the number of ridges increases, so there is a burden on sizing. Borrowed, it is 1.2mm or more is because so that the burn-out occurs between the outer peripheral surface of the well the lubricant can not be moisten by filling becomes sizing die and the ring-shaped product halfway article during sizing process. Preferably, the width of the concave groove formed on the molding surface of the molding roll is 0.05 mm, the depth is 0.05 mm, and the interval between the concave grooves is 1.0 mm. The width of the ridges formed on the surface is 0.05 mm, the height is 0.05 mm, and the interval between the ridges is 1.0 mm.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The material ring 8 made of bearing steel for bearing race is subjected to CRF processing and formed into a ring-shaped product intermediate product 10, and this ring-shaped product intermediate product 10 is used for CRF processing in order to obtain a ring-shaped body suitable for sizing processing. A plurality of concave grooves 3 having a width 6 of 0.05 mm and a depth 5 of 0.05 mm are formed on the molding surface 2 of the molding roll 1 with each interval 4 being 1 mm, and the plurality of intervals are provided. Using the forming roll 1 having the concave groove 3 on the forming surface 2, the material ring 8 is sandwiched between the mandrel 7 and the forming roll 1, and the rotating direction while pressing the forming roll 1 in the pressing direction of the arrow 20. 21, the mandrel 7 is rotated in the rotation direction 22, and the receiving roll 9 of the mandrel 7 is rotated in the rotation direction 23 to perform CRF processing, and the outer peripheral surface 11 of the ring-shaped product intermediate product 10 has a width 13 of 0.05 mm and a height. 14 is 0 Obtaining a ring-shaped product middle article 10 adapted for sizing process each interval 15 plurality of ridges 12 of 05mm and formed at 1 mm. Next, the ring-shaped product intermediate product 10 having a plurality of ridges 12 formed on the outer peripheral surface 11 is set in a sizing device, extruded in the extrusion direction of the arrow 18 by a sizing punch 17, and passed through a sizing die 16. At this time, a lubricant is put between the plurality of ridges 12 on the outer peripheral surface 11 of the intermediate product 10 of the ring-shaped product 10 and moistened and sized. Accordingly, since the outer peripheral surface 11 of the sizing die 16 and the ring-shaped product intermediate product 10 is sufficiently lubricated, the sizing process can be performed without burning between the two.
[0009]
By the above method, an accurate perfect circle with excellent roundness without causing seizure between the sizing die and the ring-shaped product in the sizing process, resulting in no seizure flaws. A product 19 was produced. Similarly, no seizure flaws are generated in the sizing die 16, so that the number of repairs of the sizing die 16 can be greatly reduced.
[0010]
【The invention's effect】
As described above, the present invention can efficiently produce a ring-shaped product having a predetermined dimension excellent in roundness and free from seizure flaws by sizing after CRF processing. The number of repairs can be greatly reduced, and the cost can be reduced.
[Brief description of the drawings]
1A and 1B are schematic views for explaining CRF processing of a ring material, where FIG. 1A is a side view and FIG. 1B is a plan view;
FIGS. 2A and 2B are schematic views for explaining formation of a groove in a forming roll used in the present invention, wherein FIG. 2A is a plan view of the forming roll, FIG. 2B is a partially enlarged view thereof, and FIG. FIG.
FIG. 3 is a partial view schematically showing a method for forming ridges on an intermediate product of a ring-shaped product by the forming roll of the present invention.
FIGS. 4A and 4B are partial views schematically showing a protrusion forming part of the intermediate product of the ring-shaped product of the present invention, in which FIG. 4A is a partial plan view, and FIG. 4B is an enlarged partial view in the circle.
FIG. 5 is a schematic diagram for explaining a method for sizing a ring-shaped product intermediate product by the sizing device of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Forming roll 2 Forming surface 3 Concave groove 4 Space | interval 5 Depth 6 Width 7 Mandrel 8 Ring material 9 Receiving prowl 10 Ring-shaped product intermediate product 11 Outer peripheral surface 12 Convex ridge 13 Width 14 Height 15 Interval 16 Sizing die 17 Sizing punch 18 Extrusion direction 19 Ring-shaped product 20 Pressing direction 21 Rotating direction 22 Rotating direction 23 Rotating direction

Claims (2)

A material ring is formed into a ring-shaped product intermediate product by cold rolling using a forming roll for outer peripheral surface processing and a mandrel for inner peripheral surface processing, and then the intermediate product of the ring-shaped product is passed through a sizing die for sizing In the ring-shaped product forming method to form a ring-shaped product, the molding has a plurality of minute concave grooves on the outer peripheral surface of the intermediate product of the ring-shaped product after cold rolling and before sizing. By cold rolling using a roll, a plurality of minute protrusions are formed, and a lubricant is moistened between the plurality of minute protrusions on the outer peripheral surface of the formed ring-shaped product, and the ring-shaped product A method of forming a ring-shaped product without seizure flaws, characterized by sizing the intermediate product through a sizing die. The minute concave groove on the molding surface of the molding roll has a width of 0.03 to 0.1 mm and a depth of 0.03 to 0.1 mm. Has a width of 0.03 to 0.1 mm and a height of 0.03 to 0.1 mm, and the interval between the plurality of grooves and the adjacent ridges of the plurality of ridges. 2. The method for forming a ring-shaped product without seizure flaws according to claim 1, wherein the intervals are 0.8 to 1.2 mm, respectively.

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