We Claim:
1. An integral-type electric power steering device comprising:
a motor component (40) including a motor that generates an assist torque corresponding to a steering torque caused by a driver in a car and applies the generated assist torque to a steering shaft (10) of the car via a reduction mechanism (20); and
a control device (50) including control-circuit elements for controlling the motor in a state where the motor component (40), the reduction mechanism (20), and the control device (50) are integrally fixed; wherein the control device (50) includes at least heating elements (531) such as a microcomputer and an FET-driving circuit, which generate heat when operated, a control board (53) on which the heating elements (531) are mounted, a power board (54) on which a power semiconductor element (541) is mounted, a mechanism component (500), to which the control board (53) and the power board (54) are fixed and an inner space of the control device which includes the control board
(53) and the power board (54); and
heat generated by the power semiconductor element
(541) is conducted to the mechanism component (500), while at least a part of the heat, which is generated by the heating elements (531), is conducted to the mechanism component (500) via a thermal-conductive component (57), wherein
the motor component (40) is arranged between the reduction mechanism (20) and the control device (50), and
the mechanism components (500) include a motor-side case
(520), which is connected to the motor component (40), and a motor-opposite-side case (510), and the control board (53) is fixed to the motor-side case (520), and the heating elements (531) are mounted on a surface of the control board (53), which faces to a wall surface of the motor-side case (520), and the thermal-conductive component (57) is arranged between the heating elements (531) and the wall surface of the motor-side case (520).
2. An integral-type electric power steering device as recited in claim 1, wherein the motor-side case
(520) includes a convex portion (5201), which is contacted to the thermal-conductive component (57), on

the wall surface.
3. An integral-type electric power steering device as recited in claim 1 or 2, wherein the control-circuit elements include a power-circuit element, which control power supplied to the motor, and a power board (54) on which at least the power-circuit element is mounted, and the power board (54) is contacted to the motor-side case (520) so as to be mounted.
4. An integral-type electric power steering device as recited in any one of claims 1 through 3, wherein a control-device-integrated motor (30) is configured in such a way that the motor component (40) and the control device (50) are integrally fixed to a rotor shaft (43) of the motor in a direction where the rotor shaft (43) is extended.
5. An integral-type electric power steering device as recited in claim 2, wherein a contact-thermal-resister-reduction means is provided on a surface of the convex portion, which is contacted to the thermal-conductive component (57).
6. An integral-type electric power steering device as recited in any one of claims 1 through 5, wherein the thermal-conductive component (57) is formed in a sheet shape.
7. An integral-type electric power steering device as recited in any one of claims 1 through 5, wherein the thermal-conductive component (57) is made from a thermal-curable resin.
8. An integral-type electric power steering device as recited in claim 7, wherein the thermal-conductive component (57), which is made from a thermal-curable resin, is installed in the control device (50) in a state where the resin is not stiffened, and then, the resin is stiffened."