US 12,214,415 B2
Dynamic load measurement method for rotary forging device, dynamic load measuring device, method for calibrating rotary forging device, method for manufacturing hub unit bearing, and method for manufacturing vehicle
Nobuyuki Hagiwara, Fujisawa (JP)
Assigned to NSK LTD., Tokyo (JP)
Appl. No. 16/968,755
Filed by NSK LTD., Tokyo (JP)
PCT Filed Feb. 13, 2019, PCT No. PCT/JP2019/005060
§ 371(c)(1), (2) Date Aug. 10, 2020,
PCT Pub. No. WO2019/159955, PCT Pub. Date Aug. 22, 2019.
Claims priority of application No. 2018-023141 (JP), filed on Feb. 13, 2018.
Prior Publication US 2020/0406338 A1, Dec. 31, 2020
Int. Cl. B21J 9/02 (2006.01); B21K 25/00 (2006.01); F16C 19/18 (2006.01); F16C 29/06 (2006.01)
CPC B21J 9/025 (2013.01) [B21K 25/00 (2013.01); F16C 19/18 (2013.01); F16C 29/0602 (2013.01)] 12 Claims
OG exemplary drawing
 
1. A dynamic load measurement method for a rotary forging device,
the rotary forging device comprising:
a forming pressing die;
a die support shaft member configured to selectively support the forming pressing die and a measuring pressing die to be rotatable about a reference axis and to freely rotate about an axis of rotation inclined at a predetermined angle with respect to the reference axis;
a support table configured to support an object to be pressed disposed at a position facing a pressing die supported by the die support shaft member in a direction of the reference axis; and
a hydraulic system having a hydraulic cylinder, a hydraulic sensor and a controller, the hydraulic cylinder being configured to apply a load in the direction of the reference axis to the object to be pressed by pressing the forming pressing die or the measuring pressing die supported by the die support shaft member against the object to be pressed supported by the support table on the basis of relative movement of the die support shaft member and the support table in the direction of the reference axis,
the method comprising
preparing the rotary forging device;
preparing the measuring pressing die;
removing the forming pressing die from the die support shaft member and supporting the measuring pressing die with the die support shaft member;
supporting the measuring pressing die by the die support shaft member, the measuring pressing die being different from the forming pressing die and having a spherical convex surface located on the reference axis,
providing a measuring shaft member as the object to be pressed by the measuring pressing die and having a circular column shape, an upper surface of the measuring shaft member being shaped to match the spherical convex surface of the measuring pressing die;
supporting the measuring shaft member by the support table and linearly guiding the measuring shaft member in the direction of the reference axis, the measuring shaft member being disposed coaxially with the reference axis, and
with using a load cell and without using the hydraulic sensor, measuring an actual load applied to the measuring shaft member along the reference axis in a state in which the spherical convex surface of the measuring pressing die is spherically engaged with and pressed against the upper surface of the measuring shaft member by the hydraulic system while the measuring pressing die is rotated about the reference axis, the load cell having an input surface with which a lower surface of the measuring shaft member is in contact, the input surface of the load cell being located directly on the reference axis and the reference axis passing through the spherical convex surface of the measuring pressing die and through a substantial contact area of the input surface of the load cell with the lower surface of the measuring shaft member when the load cell receives the actual load.