A first concave-convex portion of a first transmission member is engaged with an intermediate concave-convex portion of an intermediate transmission member with a circumferential gap being therebetween. A second concave-convex portion of a second transmission member is engaged with the intermediate concave-convex portion with a circumferential gap being therebetween. A first elastic member and a second elastic member are engaged with a first engagement portion and a second engagement portion of the intermediate transmission member such that separation between the intermediate transmission member and the first elastic member and the second elastic member can be prevented.

A driving-side concave-convex portion of a driving-side transmission member is engaged with an elastic member. The driving-side concave-convex portion is engaged with an intermediate concave-convex portion of an intermediate transmission member with a circumferential gap being interposed therebetween. A driven-side concave-convex portion of a driven-side transmission member is engaged with the elastic member. The driven-side concave-convex portion is engaged with the intermediate concave-convex portion with a circumferential gap being interposed therebetween. Both axial side surfaces and a periphery of the intermediate transmission member are covered by a side surface covering portion and a periphery covering portion of the elastic member.

A driving-side transmission portion of an output shaft of an electric motor and a driven-side transmission portion of a worm shaft are coupled to each other via a torque transmission joint including an elastic member and a coupling such that the torque can be transmitted. One axial end portion of a coupling-side concave-convex portion of the coupling is engaged with a first driving-side concave-convex portion of the driving-side transmission portion with a gap in the circumferential direction, and the other axial end portion thereof is engaged with a first driven-side concave-convex portion of the driven-side transmission portion with a gap in the circumferential direction. The elastic member is provided between an axial center portion of the coupling-side concave-convex portion, and a second driving-side concave-convex portion of the driving-side transmission portion and a second driven-side concave-convex portion of the driven-side transmission portion such that the torque can be transmitted respectively.

A driving-side transmission portion of an output shaft of an electric motor and a driven-side transmission portion of a worm shaft are coupled to each other via a torque transmission joint including an elastic member and a coupling such that the torque can be transmitted. One axial end portion of a coupling-side concave-convex portion of the coupling is engaged with a first driving-side concave-convex portion of the driving-side transmission portion with a gap in the circumferential direction, and the other axial end portion thereof is engaged with a first driven-side concave-convex portion of the driven-side transmission portion with a gap in the circumferential direction. The elastic member is provided between an axial center portion of the coupling-side concave-convex portion, and a second driving-side concave-convex portion of the driving-side transmission portion and a second driven-side concave-convex portion of the driven-side transmission portion such that the torque can be transmitted respectively.

A connection system includes two connecting elements each having a respective connecting flange on which a plurality of coupling elements are arranged along a peripheral direction and which has a substantially round external profile; and a coupling belt, on which a plurality of opposing coupling elements are arranged which are configured to form a positive-locking connection with the coupling elements of the two connecting elements for the mutual rotation-proof fixing of the two connecting elements.

A connection system includes two connecting elements each having a respective connecting flange on which a plurality of coupling elements are arranged along a peripheral direction and which has a substantially round external profile; and a coupling belt, on which a plurality of opposing coupling elements are arranged which are configured to form a positive-locking connection with the coupling elements of the two connecting elements for the mutual rotation-proof fixing of the two connecting elements.

A coupling assembly includes a flexible coupling and a first adapter. The flexible coupling defines an opening that extends along a central longitudinal axis between a first coupling end and a second coupling end. The first adapter is arranged to be at least partially received within the opening proximate the first coupling end. The first adapter extends between a first adapter first face and a first adapter second face. The first adapter defines a first adapter post and a first adapter hole. The first adapter post that extends from the first adapter first face. The first adapter hole that extends from the first adapter first face towards the first adapter second face.

A flexible coupling includes a first hub, a flexible insert having a plurality of exterior lobes and a plurality of interior lobes, a retainer having an interior which engages the exterior lobes of the flexible insert, and a second hub having an exterior surface contoured to engage the interior lobes of the flexible insert. In the event that the flexible insert were to shear or tear during operation, protruding teeth on wings of the second hub will engage sidewalls of openings formed in an inner lip of the retainer, thereby preventing the second hub from going into a potentially damaging free spin mode.

A drive-side concavo-convex part (26, 26a) is made to engage the half of a cup-side concavo-convex part (35) which is on the other side in the axial direction, while the central axes of a drive shaft (12a) and a driven shaft (8a) are aligned with each other, and drive-side gaps (36, 36a), the width of which in the circumferential direction increases toward the other side in the axial direction, are interposed between the circumferential side surface of each drive-side convex part (25, 25a) and the circumferential side surface of each cup-side convex part (34). In addition, a driven-side concavo-convex part (32, 32a) is made to engage the half of the cup-side concavo-convex part (35) which is on the one side in the axial direction, while the central axes of the drive shaft (12a) and the driven shaft (8a) are aligned with each other, and driven-side gaps (37, 37a), the width of which in the circumferential direction increases toward the one side in the axial direction, are interposed between the circumferential side surface of each driven-side convex part (31, 31a) and the circumferential side surface of each cup-side convex part (34).

Disclosed herein is a damping coupler of an electronic steering apparatus. The damping coupler includes a first spline having a first shaft hole such that a worm shaft is inserted therein, with a first serration being formed in the first shaft hole to engage with a serration of the worm shaft; a second spline coupled to a side of the first spline, and having a second shaft hole such that the worm shaft is inserted therein, with a second serration being formed in the second shaft hole to engage with a serration of the worm shaft; and a molding surrounding outsides of the first and second splines, and coupled to a motor shaft.