Rotating electric machine, temperature detector thereof, and manufacturing method and protection method thereof

1. A temperature detector for a rotating electric machine comprising:

an installation portion (1) of a first material and (2) that is a part of a wire connector conductor;

a temperature sensor including:

a detector element; and

an inner case of a second material; and

an outer case of a third material, wherein:

the temperature sensor is configured to output an electric signal indicating that a sensed temperature is at or above a predetermined threshold temperature;

the outer case substantially encloses the temperature sensor;

the inner case (1) substantially surrounds the detector element and (2) is stacked on the installation portion in a stacking direction;

a linear expansion coefficient of the outer case in a first temperature range is less than a composite linear expansion coefficient for the detector element and the inner case in the stacking direction when the inner case is stacked on the installation portion;

temperatures in the first temperature range are less than or equal to the threshold temperature; and

the first, second and third materials are different materials.

2. The temperature detector of claim 1 , wherein

the threshold temperature is a protection temperature for protecting a stator coil of the rotating electric machine.

3. The temperature detector of claim 1 , wherein

a value of the composite linear expansion coefficient is calculated by: ALav =( TH 31 ×AL 31 +TH 24 ×AL 24)/( TH 31 +TH 24), wherein:

ALav is the composite linear expansion coefficient,

AL 31 is the linear expansion coefficient of the first material used in the installation portion,

AL 24 is the linear expansion coefficient of the second material used in the inner case,

TH 31 is a thickness of the installation portion in the stacking direction, and

TH 24 is a thickness of the inner case in the stacking direction.

4. A rotating electric machine comprising:

a temperature detector, the temperature detector including:

an installation portion (1) of a first material and (2) that is a part of a stator coil of the rotating electric machine;

a temperature sensor including:

a detector element; and

an inner case made of a second material;

an outer case of a third material;

a stator having the stator coil;

a rotor magnetically coupled to the stator; and

a housing for housing the rotor, wherein

the temperature sensor is configured to output an electric signal indicating that a sensed temperature is at or above a predetermined threshold temperature;

the outer case substantially encloses the temperature sensor;

the inner case (1) substantially surrounds the detector element and (2) is stacked on the installation portion in a stacking direction;

a linear expansion coefficient of the outer case in a first temperature range is less than a composite linear expansion coefficient for the detector element and the inner case in the stacking direction when the inner case is stacked on the installation portion;

temperatures in the first temperature range are less than or equal to the threshold temperature; and

the first, second and third materials are different materials.

5. The rotating electric machine of claim 4 , further comprising:

a control device configured to determine whether a temperature measured by the temperature sensor is at or above the threshold temperature based on the electric signal.

6. A method of manufacturing a temperature detector for a rotating electric machine comprising steps of:

stacking a temperature sensor, having a detector element that is housed in an inner case of a first material, on an installation portion of a second material and that is part of a stator coil of the rotating electric machine in a stacking direction, wherein the detector element is configured to output an electric signal indicating that a detected temperature is at or above a preset threshold temperature;

molding an outer case of a third material to enclose the installation portion and the temperature sensor by using a mold; and

controlling the temperature of the mold to a target temperature;

wherein, in the stacking direction, a linear expansion coefficient of the third material in a temperature range between the target temperature and the threshold temperature to is smaller than a composite linear expansion coefficient that is based on a linear expansion coefficient of the installation portion in the temperature range and a linear expansion coefficient of the inner case in the temperature range.

7. The method of claim 6 , further comprising:

performing a protection control that protects the rotating electric machine when the detected temperature reaches the threshold temperature.

8. The method of claim 6 , further comprising the step of:

adjusting the linear expansion coefficient of the third material by adjusting an amount of filler or an amount of resin in the third material before injecting the third material into the mold, and

the composite linear expansion coefficient is calculated by:

ALav =( TH 31 ×AL 31 +TH 24 ×AL 24)/( TH 31 +TH 24)

wherein:

ALav is the composite linear expansion coefficient,

AL 31 is the linear expansion coefficient of the first material used in the installation portion,

AL 24 is the linear expansion coefficient of the second material used in the inner case,

TH 31 is a thickness of the installation portion in the stacking direction, and

TH 24 is a thickness of the inner case in the stacking direction.