A torque transmission shaft is configured having increased coupling strength between end joints and a cylindrical member to achieve high transmission torque. Misalignment and disengagement of outer collars (connection members) is effectively prevented in the step of press fitting the torque transmission shaft to another component, such as a constant velocity joint. Circlips are fitted in annular grooves formed in the end joints. The circlips abut and lock the outer collars. The outer collars each include a smaller diameter portion, and an end surface of the smaller diameter portion includes a plurality of hollow portions. The hollow portions allow a clearance between a serrated portion and the smaller diameter portion to communicate with the exterior of the outer collar. Air bubbles contained in an adhesive are allowed to escape out of the clearance through the hollow portions, and thus the clearance is filled with the adhesive densely.

A torque transmission shaft is configured having increased coupling strength between end joints and a cylindrical member to achieve high transmission torque. Misalignment and disengagement of outer collars (connection members) is effectively prevented in the step of press fitting the torque transmission shaft to another component, such as a constant velocity joint. Circlips are fitted in annular grooves formed in the end joints. The circlips abut and lock the outer collars. The outer collars each include a smaller diameter portion, and an end surface of the smaller diameter portion includes a plurality of hollow portions. The hollow portions allow a clearance between a serrated portion and the smaller diameter portion to communicate with the exterior of the outer collar. Air bubbles contained in an adhesive are allowed to escape out of the clearance through the hollow portions, and thus the clearance is filled with the adhesive densely.

A vehicle steering system and a vehicle are provided. The vehicle steering system includes a steering shaft and a steering transmission shaft. The steering shaft or the steering transmission shaft includes a first shaft section and a second shaft section. A clutch mechanism is arranged between the first shaft section and the second shaft section. In an engaging state, a transmission connection is established between the first shaft section and the second shaft section and in this case, a controller determines that the vehicle enters a driving mode. In a disengaging state, the transmission connection between the first shaft section and the second shaft section is disconnected, and in this case, the control modulecontroller determines that the vehicle enters a game mode.

A vehicle steering system and a vehicle are provided. The vehicle steering system includes a steering shaft and a steering transmission shaft. The steering shaft or the steering transmission shaft includes a first shaft section and a second shaft section. A clutch mechanism is arranged between the first shaft section and the second shaft section. In an engaging state, a transmission connection is established between the first shaft section and the second shaft section and in this case, a controller determines that the vehicle enters a driving mode. In a disengaging state, the transmission connection between the first shaft section and the second shaft section is disconnected, and in this case, the control modulecontroller determines that the vehicle enters a game mode.

According to the present disclosure, there is provided a structure of an electric power steering device in which its steering shafts are connected includes a torsion bar connected to a steering wheel; an input shaft surrounding the torsion bar on an input side of the torsion bar;

and an output shaft surrounding one end of the input shaft and the torsion bar on an output side of the torsion bar, wherein the one end of the input shaft is inserted into and coupled to one end of the output shaft, and a copper bush and a needle bearing are disposed side by side between an outer circumferential surface of the one end of the input shaft and an inner circumferential surface of the one end of the output shaft.

According to the present disclosure, there is provided a structure of an electric power steering device in which its steering shafts are connected includes a torsion bar connected to a steering wheel; an input shaft surrounding the torsion bar on an input side of the torsion bar;

and an output shaft surrounding one end of the input shaft and the torsion bar on an output side of the torsion bar, wherein the one end of the input shaft is inserted into and coupled to one end of the output shaft, and a copper bush and a needle bearing are disposed side by side between an outer circumferential surface of the one end of the input shaft and an inner circumferential surface of the one end of the output shaft.

A low surface-roughness part is formed at a first tapered part, and, as a result, the roughness of an opening-edge of a groove part of an internal spline part that opens at the first tapered part is reduced, and surface pressure applied by the opening edge to a tooth of an external spline part can be reduced. As a result, the opening edge of the groove part of the internal spline part can be kept from digging into the tooth, and variation, between products, in the insertion load of a second shaft part can be suppressed.

To provide a method of manufacturing a shaft for a steering device, the shaft including a spline shaft part to be coupled with an input shaft, a stopper part to be coupled with an output shaft, and an intermediate shaft part that couples the spline shaft part with the stopper part. The method includes: a step of forming a hole part recessed in an axial direction from one end of a pillar-shaped material by forging; and a step of pressing the material in which the hole part has been formed into a die to perform drawing in a radial direction on a portion of the material at which the spline shaft part and the intermediate shaft part are formed, and prolonging a length along the axial direction of the hole part at the same time by forging.

To provide a method of manufacturing a shaft for a steering device, the shaft including a spline shaft part to be coupled with an input shaft, a stopper part to be coupled with an output shaft, and an intermediate shaft part that couples the spline shaft part with the stopper part. The method includes: a step of forming a hole part recessed in an axial direction from one end of a pillar-shaped material by forging; and a step of pressing the material in which the hole part has been formed into a die to perform drawing in a radial direction on a portion of the material at which the spline shaft part and the intermediate shaft part are formed, and prolonging a length along the axial direction of the hole part at the same time by forging.

The present invention provides a coupling device for coupling a rotary actuator to a mechanical device having a rotatable shaft. The coupling device comprises a spring return module with a first rotatable coupling configured to engage a first portion of the shaft, and a spring engaged with the first rotatable coupling, wherein the first rotatable coupling is rotatable about a rotation axis, and wherein rotation of the rotatable coupling about the rotation axis in a first direction causes mechanical energy to be stored in the spring. The coupling device further comprises an actuator coupling module comprising a second rotatable coupling. The second rotatable coupling is configured to engage a second portion of the shaft, the second rotatable coupling being further engageable with an output of the rotary actuator. The second rotatable coupling is rotatable about the rotation axis, the second rotatable coupling being rotatable relative to the first rotatable coupling about the rotation axis.