Method for retaining member by caulking

Abstract

During a caulking process, a pressure is applied to a pressure receiving shoulder portion in the same direction as a direction of a clamping force generated by a caulking portion. The clamping force for holding an outer race can thereby be increased. Also, a pressure receiving surface of the pressure receiving shoulder portion is set higher than an end face. Thus, no pressure resulting from plastic deformation in a direction perpendicular to the direction of the clamping force of the caulking portion is generated. In addition, a groove is formed between the pressure receiving shoulder portion and an end serving as the caulking portion.

What is claimed is: 
     
         1 . A method for retaining a member by caulking, comprising:
 bending an end of a workpiece along a corner portion of the member by a caulking surface of a caulking roller;   applying a pressure to a pressure receiving shoulder portion, which is formed coaxially on the outside of a bent side of the end of the workpiece, in a same direction as a caulking pressure applied to the caulking surface so that a caulking process is performed to form a caulked portion, and the member is held along a base of the workpiece by a clamping force of the caulked portion; and   setting a timing for starting a caulking end process to a timing when a caulking load applied to the caulking roller during the caulking process or a caulking torque for rolling the caulking roller undergoes a specific change indicating that the member begins to be strained.   
     
     
         2 . The method according to  claim 1 , wherein the workpiece is a caulked retaining member that includes a groove between the bent side and the pressure receiving shoulder portion. 
     
     
         3 . The method according to  claim 1 , wherein the caulking roller applies the pressure to the pressure receiving shoulder portion. 
     
     
         4 . The method according to  claim 1 , wherein the specific change indicating that the member begins to be strained is an abrupt increase in the caulking load. 
     
     
         5 . The method according to  claim 1 , wherein the specific change indicating that the member begins to be strained is an abrupt decrease in the caulking torque. 
     
     
         6 . The method according to  claim 1 , wherein:
 the member is a bearing; and   the workpiece is a housing that accommodates a rotary member rotatably supported by the bearing, or a bearing holder arranged in the housing.   
     
     
         7 . The method according to  claim 6 , wherein:
 the bearing and the housing or the bearing holder are a bearing and a housing or a bearing holder in a rotation-translation conversion actuator respectively; and   the housing is mounted to a driven object device, the rotation-translation conversion actuator also includes an output shaft, which moves in an axial direction of the workpiece through rotation of the rotary member, and protrudes outward from the housing to transmit a driving force from the output shaft to the driven object device.   
     
     
         8 . The method according to  claim 7 , wherein:
 the rotary member is a nut of a planetary differential screw type rotation-translation converter;   the output shaft is a sun shaft;   a planetary shaft is arranged between the nut and the sun shaft; and   the sun shaft and the planetary shaft mesh with the nut in a manner to perform rotation-translation conversion.   
     
     
         9 . The method according to  claim 7 , wherein the driven object device is an internal combustion engine. 
     
     
         10 . The method according to  claim 3 , wherein the caulking surface formed on the caulking roller and a pressing surface for applying the pressure to the pressure receiving shoulder portion are formed as a stepless cylindrical surface.