초록

A thermostat comprises a valve and an electric valve actuator to move the valve against a valve seat. The thermostat comprises a wax motor responsive to temperature to move the valve away from the valve seat.

대표청구항 ▼

1. A thermostat comprising a valve, an electric valve actuator comprising an output member axially movable to a valve-seating position to move the valve into contact with a valve seat, a bearing surface, and a wax motor responsive to a predetermined temperature to act against the bearing

1. A thermostat comprising a valve, an electric valve actuator comprising an output member axially movable to a valve-seating position to move the valve into contact with a valve seat, a bearing surface, and a wax motor responsive to a predetermined temperature to act against the bearing surface to move the valve axially away from the valve seat and relative to the bearing surface when the output member is positioned in the valve-seating position. 2. The thermostat of claim 1, wherein the electric valve actuator comprises an electric motor to move the output member.3. The thermostat of claim 2, wherein the electric motor is a stepper motor.4. The thermostat of claim 1, comprising a spring between the output member and the wax motor.5. The thermostat of claim 1, wherein the wax motor comprises a piston and a thermal expansion device comprising temperature responsive wax expandable to relatively move the piston and the thermal expansion device to move the valve away from the valve seat when the output member is positioned in the valve-seating position.6. The thermostat of claim 5, comprising a spring unit comprising a spring positioned between the output member and the thermal expansion device and a sleeve that surrounds the spring and extends between the thermal expansion device and the valve to transmit motion of the thermal expansion device to the valve.7. The thermostat of claim 5, wherein the piston engages the bearing surface when the output member is positioned in the valve-seating position and disengages the bearing surface when the output member moves away from the valve-seating position.8. The thermostat of claim 1, comprising a housing in which the valve and the wax motor are positioned, wherein the wax motor comprises a piston and a thermal expansion device that receives the piston and is responsive to temperature to cause relative movement between the thermal expansion device and the piston, and the housing comprises a flange formed to include a bore receiving the piston and providing the bearing surface.9. The thermostat of claim 2, wherein the wax motor is arranged to move the valve axially toward the electric motor when the output member is positioned in the valve-seating position and the wax motor is exposed to the predetermined temperature.10. A thermostat for controlling flow of coolant to control the temperature of a heated device, the thermostat comprising a house having a bearing surface a valve positioned in the housing, an electric valve actuator comprising an output member axially movable relative to the housing to a valve-seating position to move the valve relative to the housing axially in coolant into contact with a valve seat, the valve comprising a coolant passageway extending axially through the valve to receive coolant therethrough to facilitate axial movement of the valve in the coolant by the output member, and a wax motor responsive to a predetermined temperature to act against the housing to move the valve axially away from the valve seat and relative to the bearing surface when the output member is positioned in the valve-seating position. 11. The thermostat of claim 10, wherein the electric valve actuator comprises an electric motor to move the output member.12. The thermostat of claim 11, wherein the electric motor is a stepper motor.13. The thermostat of claim 10, wherein the valve comprises a sleeve comprising the coolant passageway, and the sleeve comprises a first end providing an inlet of the coolant passageway and a second end providing an outlet of the coolant passageway.14. The thermostat of claim 10, comprising axially spaced first and second valve seats, wherein the electric valve actuator comprises an electric motor to axially move the output member between a first valve-seating position positioning the valve against the first valve seat and apart from the second valve seat and a second valve-seating position positioning the valve against the second valve sea t and apart from the first valve seat.15. The thermostat of claim of claim 10, comprising a spring unit positioned in the coolant flow passageway, wherein the valve comprises a valve sleeve and an arm extending radially inwardly from the valve sleeve, the valve sleeve comprises the coolant passageway, the spring unit comprises an overshoot spring and a spring sleeve, the overshoot spring is positioned between the output member and the wax motor to take up motion of the output member relative to the wax motor due to axial movement of the output member beyond the valve-seating position, the sprint sleeve surrounds the overshoot spring and is coupled to the wax motor and the arm.16. The thermostat of claim 10, comprising a housing in which the valve and the wax motor are positioned, wherein the wax motor comprises a piston and a thermal expansion device that receives the piston and is responsive to temperature to cause relative movement between the thermal expansion device and the piston, and the housing comprises a flange formed to include a bore receiving the piston and providing the bearing surface.17. A thermostat for controlling flow of coolant between a heated device and a heat exchanger to control the temperature of the heated device, the thermostat comprising a housing comprising a coolant inlet to admit coolant from the heated device into the housing, a first coolant outlet to discharge coolant to the heat exchanger, and a second coolant outlet to discharge coolant back to the heated device to bypass the heat exchanger, a valve positioned in the housing, first and second valve seats, an electric valve actuator comprising an output member and an electric motor to axially move the output member relative to the housing between a first valve-seating position positioning the valve against the first valve seat to block coolant flow between the coolant inlet and the first coolant outlet and apart from the second valve seat to allow coolant flow between the coolant inlet and the second coolant outlet and a second valve-seating position positioning the valve against the second valve seat to block coolant flow between the coolant inlet and the second coolant outlet and apart from the first valve seat to allow coolant flow between the coolant inlet and the first coolant outlet, and a wax motor positioned in the housing and comprising a piston and a thermal expansion device comprising wax responsive to a predetermined temperature to cause the piston to act against the housing to move the thermal expansion device axially relative to the piston to move the valve axially away from the first valve seat to allow flow between the coolant inlet and the first coolant outlet when the electric motor positions the output member in the first valve-seating position. 18. The temperature control system of claim 17, wherein the valve, output member, and wax motor are coaxial.19. The temperature control system of claim 17, comprising a spring unit, wherein the valve comprises a valve sleeve and an arm extending radially inwardly from the valve sleeve, the spring unit comprises a spring positioned between the output member and the thermal expansion device and a spring sleeve that surrounds the spring and extends between the thermal expansion device and the arm to move the valve sleeve away from the first valve seat in response to relative movement between the piston and the thermal expansion device due to expansion of the wax when the electric motor positions the output member in the first valve-seating position.20. The temperature control system of claim 17, wherein the housing comprises a piston bearing surface which the piston engages when the electric motor positions the output member in the first valve-seating position and which the piston disengages when the electric motor positions the output member in the second valve-seating position.21. The temperature control system of claim 17, wherein the electric motor requires no electri c power to maintain the output member in the first and second valve-seating positions.22. The temperature control system of claim 17, wherein the valve defines a coolant passageway extending axially through the valve to facilitate movement of the valve in the coolant by the output member.23. The thermostat of claim 17, wherein the bearing surface is provided by a bore formed in a flange included in the housing and coupled to the coolant inlet.