Sun tracking mechanism

Abstract

A sun tracking mechanism is provided for solar power generation, including a power unit, a linear actuator and at least two universal joints. The sun tracking mechanism outputs an angle of high precision by two axial directions provided from the universal joints, the power unit and the linear actuator. A solar power module disposed on the sun tracking mechanism generates electricity in the best light incident angle. In addition, the linear actuator provides an auxiliary supporting force to improve the wind-resistant capability.

What is claimed is: 
     
         1 . A sun tracking mechanism, comprising:
 a base;   a first universal joint;   a second universal joint;   a pole having a fixing end fixed to the base and a connecting end connected to the first universal joint;   a power unit disposed on the connecting end of the pole for providing a transmission force to the first universal joint;   a linear actuator having a first end connected to the second universal joint and a second end connected to the base and being switched between a stretching state and a contracted state; and   a plate having a first surface pivotally connected to the first universal joint and the second universal joint and a second surface opposing the first surface, wherein the first universal joint allows the plate to rotate around a first axial direction and/or a second axial direction,   wherein the plate rotates around the first axial direction with the first universal joint as a pivot when the power unit provides the transmission force to the first universal joint, and rotates around the second axial direction with the first universal joint as the pivot when the linear actuator is switched between the stretching state and the contracted state.   
     
     
         2 . The sun tracking mechanism of  claim 1 , wherein the first universal joint further comprises:
 a first socket connected to the connecting end of the pole and having two openings;   a second socket pivotally connected to the first surface of the plate and having two openings; and   a cross shaft having four shaft ends wherein, two opposing ones of which are disposed in the openings of the first socket to allow the first universal joint to rotate around the first axial direction through a relative motion between the cross shaft and the first socket, and the others of which are disposed in the openings of the second socket to allow the first universal joint to rotate around the second axial direction through a relative motion between the cross shaft and the second socket.   
     
     
         3 . The sun tracking mechanism of  claim 2 , further comprising a first pivot member passing through the second socket such that the second socket props against the plate, and the second socket rotates around a third axial direction through the first pivot member when a relative motion is performed between the second socket and the plate. 
     
     
         4 . The sun tracking mechanism of  claim 3 , wherein the power unit has a first gear disposed thereon, one of the shaft ends of the cross shaft along the first axial direction has a second gear disposed thereon, and the first gear and the second gear are engaged to transmit the transmission force of the power unit to the cross shaft, for providing a force needed by the cross shaft to rotate around the first axial direction. 
     
     
         5 . The sun tracking mechanism of  claim 1 , wherein the second universal joint further comprises:
 a third socket connected to the first end of the linear actuator and having two openings;   a fourth socket pivotally connected to the first surface of the plate and having two openings; and   a cross shaft having four shaft ends, wherein two opposing ones of which are disposed in the openings of the third socket to allow the second universal joint to rotate around a fourth axial direction through a relative motion between the cross shaft and the third socket, and the others of which are disposed in the openings of the fourth socket to allow the second universal joint to rotate around a fifth axial direction through a relation motion between the cross shaft and the fourth socket.   
     
     
         6 . The sun tracking mechanism of  claim 5 , further comprising a second pivot member passing through the fourth socket such that the fourth socket props against the plate, and the fourth socket rotates around a sixth axial direction through the second pivot member when a relative motion is performed between the fourth socket and the plate, wherein when the plate rotates around the first axial direction or the second axial direction, the second universal joint, by rotating itself around the fourth axial direction, the fifth axial direction or the sixth axial direction, provides a degree of freedom needed by the second universal joint to move in accordance with the plate. 
     
     
         7 . The sun tracking mechanism of  claim 5 , further comprising a third universal joint disposed between the linear actuator and the base, the third universal joint comprising:
 a fifth socket fixed to the second end of the linear actuator and having two openings;   a sixth socket fixed to the base and having two openings; and   a cross shaft having four shaft ends, two opposing ones of which are disposed in the openings of the fifth socket to allow the third universal joint to rotate around the fourth axial direction through a relative motion between the cross shaft and the fifth socket, and the others of which are disposed in the openings of the sixth socket to allow the third universal joint to rotate around the fifth axial direction through a relative motion between the cross shaft and the sixth socket.   
     
     
         8 . The sun tracking mechanism of  claim 1 , wherein the power unit is a servo motor, a stepping motor or a linear motor, and the first universal joint or the second universal joint is a ball joint. 
     
     
         9 . The sun tracking mechanism of  claim 1 , wherein the power unit has a first gear disposed thereon, the first universal joint has a second gear disposed thereon, and the first gear and the second gear are engaged to transmit the transmission force of the power unit to the first universal joint, for providing a force needed by the first universal joint to rotate around the first axial direction. 
     
     
         10 . The sun tracking mechanism of  claim 1 , wherein the first universal joint is pivotally connected to a central point of the first surface of the plate.