Method for controlling the temperature of an electric motor, and fluid supply device

A fluid supply device, comprising:

• an electric motor;
• a clutch;
• and
• a fluid pump configured to convey a fluid flow of a fluid supplying the electric motor to alter a motor operating temperature of the electric motor, the fluid pump being selectively switchable between a first operating state and a second operating state based on a comparison between one actual value of a safety characteristic value of the electric motor to a predetermined limit value of the safety characteristic value, the fluid being a cooling oil, the fluid pump being rotatable in a first direction of rotation and a second direction of rotation, the fluid supply device comprising a clutch, the fluid flow being provided for cooling the electric motor and the clutch during rotational movement in the first direction of rotation such that the fluid flow alters the motor operating temperature of the electric motor, the fluid pump rotating in the first direction of rotation in the first operating state;
• and
• in the second operating state, the fluid flow being provided for building up a fluid pressure for actuating the clutch during rotational movement in the second direction of rotation;
• wherein, in the first operating state, the fluid flow is adjusted according to a predetermined operating characteristic value of the electric motor, and, in the second operating state, the fluid flow is adjusted so as to be higher than in the first operating state,
• wherein, in the first operating state, the fluid flow is calculated:
• based on the predetermined operating characteristic value of the electric motor when a first loss characteristic value is greater than a second loss characteristic value;
• and
• based on a fluid operating temperature of the fluid supply device when the second loss characteristic value is greater than or equal to the first loss characteristic value;
• wherein the first loss characteristic value characterizes an electrical power loss of the electric motor during operation of the electric motor;
• wherein the second loss characteristic value characterizes a mechanical power loss of the electric motor during operation of the electric motor.