The invention provides a connection device for a joint shaft in a motor vehicle. The connection device includes an axis of rotation, a first connection area for connecting the connection device to a drive train element, a predetermined breaking region, and a tube region which connects directly to the predetermined breaking region. The connection device has an axial extension in the direction of the axis of rotation, and a radial extension orthogonal to the axis of rotation and is designed, at least substantially, as a tubular hollow body. The predetermined breaking region is arranged between the first connection region and the tube region in the axial direction. A connection area is arranged in the axial direction between the first connection region and the predetermined breaking region.

A telescopic rod structure includes an upper rod and a lower rod. The upper rod includes a first rod body and a second rod body. A diameter of the first rod body is less than a diameter of the second rod body. A rod stepped surface is formed between the first rod body and the second rod body. An outer wall of the second rod body defines a guide groove. The lower rod defines a first through hole and a second through hole. A diameter of the first through hole is less than a diameter of the second through hole. A hole stepped surface is formed between the first through hole and the second through hole. A rib is arranged on the second through hole. The second rod body is sleeved in the second through hole. The first rod body upwards passes through the first through hole.

A telescopic rod structure includes an upper rod and a lower rod. The upper rod includes a first rod body and a second rod body. A diameter of the first rod body is less than a diameter of the second rod body. A rod stepped surface is formed between the first rod body and the second rod body. An outer wall of the second rod body defines a guide groove. The lower rod defines a first through hole and a second through hole. A diameter of the first through hole is less than a diameter of the second through hole. A hole stepped surface is formed between the first through hole and the second through hole. A rib is arranged on the second through hole. The second rod body is sleeved in the second through hole. The first rod body upwards passes through the first through hole.

An intermediate shaft includes a first hollow shaft portion in which a plurality of grooves are formed in a longitudinal direction thereof, a second hollow shaft portion coupled at one end thereof to a first slip member, provided to be accommodated inside the first hollow shaft portion, and slipped into the first hollow shaft portion when a collision occurs, and a shaft portion to which a second slip member is coupled, provided to be accommodated inside the second hollow shaft portion, and slipped into the second hollow shaft portion when the collision occurs. A first press-in portion is formed on an inner circumference of the first hollow shaft portion to protrude therefrom, thereby pressing and supporting the first slip member.

An intermediate shaft includes a first hollow shaft portion in which a plurality of grooves are formed in a longitudinal direction thereof, a second hollow shaft portion coupled at one end thereof to a first slip member, provided to be accommodated inside the first hollow shaft portion, and slipped into the first hollow shaft portion when a collision occurs, and a shaft portion to which a second slip member is coupled, provided to be accommodated inside the second hollow shaft portion, and slipped into the second hollow shaft portion when the collision occurs. A first press-in portion is formed on an inner circumference of the first hollow shaft portion to protrude therefrom, thereby pressing and supporting the first slip member.

A motor vehicle drive shaft has a receptacle tube component with a receptacle internal diameter and a push-fit component with a push-fit external diameter. The push-fit external diameter is smaller than or equal to the receptacle internal diameter. The receptacle tube component and the push-fit component can be rotated about a common drive shaft rotational axis and extend along the latter in a longitudinal direction. The receptacle tube component and the push-fit component are connected to one another for the transmission of torque. A connecting component is provided, wherein the connecting component is connected in a torque-conducting manner to the receptacle tube component by way of a receptacle connection. The connecting component is connected to the push-fit component by way of a push-fit connection. At least one of the two connections is configured as a combined frictionally locking and positively locking shaft/hub connection.

The protection system (5) comprises a first tubular member (13) and a second tubular member (15) which can be slidably inserted into each other and a protection (8) at one end of the first tubular member (13). The protection comprises a protective boot (40) and a first annular element (21) fixed to the first tubular member (13). Further provided for is a second annular element (33) which can be torsionally coupled to the first annular element (21) and which can be decoupled therefrom by means of a mutual movement between the first annular element (21) and the second annular element (33) in a direction approximately parallel to the axis (A-A) of the first tubular member (13). The second annular element (33) is coupled to the protective boot (40) which is provided with members (49) for coupling to a stationary plate (51) which can be connected to a power take-off (9). A drive shaft provided with such a protection system is also described.

The protection system (5) comprises a first tubular member (13) and a second tubular member (15) which can be slidably inserted into each other and a protection (8) at one end of the first tubular member (13). The protection comprises a protective boot (40) and a first annular element (21) fixed to the first tubular member (13). Further provided for is a second annular element (33) which can be torsionally coupled to the first annular element (21) and which can be decoupled therefrom by means of a mutual movement between the first annular element (21) and the second annular element (33) in a direction approximately parallel to the axis (A-A) of the first tubular member (13). The second annular element (33) is coupled to the protective boot (40) which is provided with members (49) for coupling to a stationary plate (51) which can be connected to a power take-off (9). A drive shaft provided with such a protection system is also described.

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.

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.