Variable speed alternator
View Patent ↗A variable speed alternator can include a shaft and adjustable pulley assembly coupled to the shaft. The adjustable pulley assembly can include a support member fixed to the shaft and an adjustable pulley moveably coupled to the support member. The adjustable pulley can have a plurality of individually moveable members each with an outer surface forming a portion of a belt engaging surface for receiving a flat belt to drive the adjustable pulley. Each moveable member can be selectively linearly moveable in a radial direction to vary an outer diameter of the adjustable pulley between a first position having a first outer diameter and a second position having a second outer diameter to selectively vary a driven speed of the alternator shaft.
1. A variable speed alternator system for a vehicle having an engine, the variable speed alternator system comprising:
a control arrangement including a controller operatively coupled to an alternator speed sensor and an engine speed sensor;
an alternator shaft; and
an adjustable pulley assembly coupled to the alternator shaft, the pulley assembly including:
a support member fixed to the alternator shaft; and
an adjustable pulley moveably coupled to the support member, the adjustable pulley having a plurality of individually moveable members; and
a plurality of actuation members each coupled to a respective one of the plurality of moveable members and the support member, each actuation member operatively associated with the controller;
wherein each moveable member includes an arcuate shaped outer surface forming a portion of a belt engaging surface for receiving a flat belt to drive the adjustable pulley; and
wherein the controller is configured to cause the plurality of actuation members to selectively linearly translate the plurality of moveable members in a radial direction to vary an outer diameter of the adjustable pulley between an unexpanded state having a first outer diameter and an expanded state having a second outer diameter to selectively vary a driven speed of the alternator shaft in response to an output of at least one of the alternator speed sensor and the engine speed sensor; and wherein the plurality of moveable members each extend radially between the arcuate shaped outer surface and an arcuate shaped inner surface, the arcuate shaped outer surface of each moveable member extending circumferentially to form the outer diameter with the arcuate shaped outer surfaces of adjacent moveable members when the moveable members are arranged in the first position and the arcuate shaped inner surface of each moveable member extending circumferentially to form an inner diameter with the arcuate shaped inner surfaces of adjacent moveable members when the moveable members are arranged in the first position such that the arcuate shaped inner surfaces of the moveable members circumscribe and directly engage the alternator shaft when the moveable members are arranged in the first position.
2. The system of claim 1 , wherein the plurality of moveable members includes four moveable members and the plurality of actuation members includes four actuation members, and wherein the outer surface of each of the four moveable members extends ninety degrees circumferentially.
3. The system of claim 1 , wherein the actuation members include linear electromechanical actuators.
4. The system of claim 1 , wherein the each moveable member includes a connecting member, and wherein the support member includes a plurality of radially extending channels each configured to receive one of the connection members to rotationally fix the moveable members to the support member while allowing radial movement of moveable members relative to the support member.
5. The system of claim 4 , wherein the channels extend linearly in the radial direction and are sized and shaped to limit a radial range of motion of the moveable members so as to define the first and second outer diameters of the adjustable pulley in the respective expanded and unexpanded states, the first diameter being smaller than the second diameter.
6. The system of claim 1 , wherein the controller is configured to cause the actuation members to position the moveable members of the adjustable pulley in the unexpanded state having the first diameter to increase a current output of the alternator in response to a signal from the engine speed sensor indicating the engine is at an idle condition.
7. The system of claim 1 , wherein the controller is configured to cause the actuation members to position the moveable members of the adjustable pulley in the expanded state having the second diameter to decrease a driven speed of the alternator shaft in response to a signal from the engine speed sensor indicating the engine is at a non-idle condition and in response to input from the alternator speed sensor.
8. The system of claim 1 , further comprising an electrical load sensor operatively associated with the controller and configured to sense a current electrical load of the vehicle;
wherein the controller is configured to cause the actuation members to position the moveable members of the adjustable pulley in the unexpanded state having the first diameter to increase a current output of the alternator in response to a signal from the engine speed sensor indicating the engine is at an idle condition and in response to input from the electrical load sensor.
9. A variable speed alternator, comprising;
an alternator shaft; and
an adjustable pulley assembly coupled to the alternator shaft, the pulley assembly including:
a support member fixed to the alternator shaft and having an outer diameter;
an adjustable pulley moveably coupled to the support member, the adjustable pulley having a plurality of individually moveable members each with an arcuate shaped outer surface forming a portion of a belt engaging surface for receiving a flat belt to drive the adjustable pulley, each moveable member being selectively linearly moveable in a radial direction to vary an outer diameter of the adjustable pulley between a first position having a first outer diameter and a second position having a second outer diameter to selectively vary a driven speed of the alternator shaft;
wherein the first outer diameter of the adjustable pulley is smaller than the second outer diameter of the adjustable pulley, the first outer diameter of the adjustable pulley being smaller than the outer diameter of the support member and the second outer diameter of the adjustable pulley being lamer than the outer diameter of the support member; and wherein the plurality of moveable members each extend radially between the arcuate shaped outer surface and an arcuate shaped inner surface, the arcuate shaped outer surface of each moveable member extending circumferentially to form the outer diameter with the arcuate shaped outer surfaces of adjacent moveable members when the moveable members are arranged in the first position and the arcuate shaped inner surface of each moveable member extending circumferentially to form an inner diameter with the arcuate shaped inner surfaces of adjacent moveable members when the moveable members are arranged in the first position such that the arcuate shaped inner surfaces of the moveable members circumscribe and directly engage the alternator shaft when the moveable members are arranged in the first position.
10. The variable speed alternator of claim 9 , further comprising a plurality of actuation members, wherein each of the plurality of actuation members is coupled to one of the plurality of moveable members and the support member, the plurality of actuation members being configured to selectively linearly move the corresponding plurality of moveable members relative to the support member.
11. The variable speed alternator of claim 10 , wherein each moveable member of the adjustable pulley includes a connecting member for moveably coupling each moveable member to the support member.
12. The variable speed alternator of claim 11 , wherein the support member includes a plurality of radially extending channels each configured to receive one of the connecting members to moveable couple the moveable members to the support member.
13. The variable speed alternator of claim 12 , wherein the channels extend linearly in the radial direction and are sized and shaped to limit a radial range of motion of the moveable members so as to define the first and second outer diameters of the adjustable pulley.
14. The variable speed alternator of claim 10 , wherein the actuation members include electromechanical actuation members.
15. The variable speed alternator of claim 10 , wherein the actuation members are linear solenoids.
16. The variable speed alternator of claim 9 , wherein the plurality of moveable members each extend radially in a wedge shaped configuration that is substantially parallel to the support member and a plurality of actuation members are disposed axially between the plurality of moveable members on one side and the support member on another side.
17. The variable speed alternator of claim 9 , wherein the support member includes a first support member and a second support member spaced apart from each other and fixed to the alternator shaft, the plurality of moveably members of the adjustable pulley positioned between the first and second support members and each moveably coupled to both the first and second support members.
18. The variable speed alternator of claim 9 , wherein the first position comprises an unexpanded state and the second position comprises an expanded state of the adjustable pulley.