Speed increaser

An electric compressor comprising:

• an electric motor driving to rotate a low-speed shaft;
• a speed increaser including a high-speed shaft and transmitting a rotation of the low-speed shaft to the high-speed shaft, and
• a compression part connected to the high-speed shaft and compressing a fluid with a rotation of the high-speed shaft,
• wherein the speed increaser includes an annular peripheral wall disposed coaxially with the low-speed shaft and rotatable with a rotation of the low-speed shaft, the high-speed shaft disposed within the peripheral wall and having a rotation axis extending in the same direction as a rotation axis of the peripheral wall, and three rollers disposed within the peripheral wall and in contact with both the peripheral wall and the high-speed shaft,
• wherein the three rollers are disposed at different positions along the rotation axis of the high-speed shaft with rotation axes of the three rollers extending in the same direction as the rotation axis of the high-speed shaft, and the rotation axes of the three rollers are spaced in a circumferential direction of the high-speed shaft, and
• wherein the three rollers are disposed so that at least part of contact areas between the high-speed shaft and the rollers is free from overlapping with each other along the rotation axis of the high-speed shaft.