A disc for use in a disc spring, and a disc spring assembly comprising the disc

A disc for a disc spring, the disc comprising:

• a first face forming a surface of a concave face of the disc;
• a second face opposite the first face;
• a central bore extending through the disc;
• and
• a perimeter face
• the first face comprising:
• a first portion having a direction component extending radially from the perimeter face towards a central axis of the bore;
• and
• a second portion between the first portion and the central bore wherein the first portion is planar and arranged at a first angle with respect to the central axis of the bore, and the second portion comprises at least a part arranged at a second angle with respect to the central axis of the bore wherein the second angle is smaller than the first angle;
• wherein the disc is configured so that the first angle is smaller than 90° with respect to a central axis of the bore when the disc is unloaded, and the first angle is larger than 90° with respect to the central axis of the bore when the disc is subject to a load being at least 30% of a design load of the disc
• wherein the second face comprises:
• a third portion extending from the bore and towards the perimeter face and having a direction component extending radially from the central axis through the bore;
• and
• a fourth portion between the third portion and the perimeter face,
• wherein the third portion is planar and arranged at a third angle with respect to the central axis of the bore, and the fourth portion comprises at least a part arranged at an acute fourth angle with respect to the central axis of the bore, and
• wherein the fourth angle is smaller than the third angle.