Pump shaft for a multi-stage pump

A pump, comprising:

• a pump shaft having a circumferential groove region;
• and
• a load-relieving device,
• wherein
• the circumferential groove region is configured to receive and cooperate with the load-relieving device to impart a force acting in the axial direction of the pump shaft to the pump shaft,
• the groove region in an axial direction of the pump shaft includes a plurality of grooves spaced apart from one another in the axial direction,
• the plurality of grooves are circumferential grooves separated from one another or are portions of a single-start or multi-start closed screwthread,
• a respective groove base of each of the plurality of grooves, viewed in the axial direction, has a shape of a segment of a circle,
• radii of the groove base relative to an axis of rotation of the pump shaft are different, and
• the groove region is not tapered.

A pump shaft for a multi-stage pump, comprising:

• a pump shaft having a circumferential groove region configured to receive and cooperate with a load-relieving device to impart a force acting in the axial direction of the pump shaft to the pump shaft, wherein
• the groove region in an axial direction of the pump shaft includes a plurality of grooves spaced apart from one another in the axial direction,
• the plurality of grooves having tooth tips form a sawtooth structure in the axial direction,
• radii of the tooth tips of the sawtooth structure with respect to an axis of rotation of the pump shaft are the same, and
• at least one tooth base of the sawtooth structure has a larger radius with respect to the axis of rotation of the pump shaft than a smaller radius of at least one other of the tooth bases of the sawtooth structure.

A pump, comprising:

• a pump shaft having a circumferential groove region;
• and
• a load-relieving device,
• wherein
• the circumferential groove region is configured to receive and cooperate with the load-relieving device to impart a force acting in the axial direction of the pump shaft to the pump shaft,
• the groove region in an axial direction of the pump shaft includes a plurality of grooves spaced apart from one another in the axial direction,
• an inner circumference of the load-relieving device is configured to engage in the plurality of grooves of the groove region of the pump shaft,
• the inner circumference of the load-relieving device includes a plurality of thread elements configured to engage in at least one of the plurality of grooves in the groove region,
• at least one of the plurality of thread elements of the load-relieving device is radially shorter relative to an axis of rotation of the of the load-relieving device relative to another one of the plurality of thread elements, and
• the at least one radially shorter one of the plurality of thread elements is configured to engage one of the plurality of grooves adjacent to at an outer edge of the groove region.