The difference between a worm gear and a worm
To judge who is the worm gear and the worm, as long as it can be used as the driving part is the worm, and the driven part is the worm gear, because the worm gear and worm drive pair have self-locking characteristics. In the adjustable wrench, the part that adjusts the opening and closing of the wrench with the thumb is the worm, because the part of the movable wrench opening cannot be used as the driving part.
(1) The worm gear is equal to the gear; the worm is equal to the rack.
(2) The worm is the driving part; the worm gear is the driven part.
(3) Many worm gears have an interesting feature that other gear sets do not have: the worm can easily turn the gear, but the gear cannot turn the worm. This is because the lobes on the screw are so shallow that the friction between the gear and the screw keeps the screw in place when the gear tries to turn the screw.
2. Judgment of the direction of rotation
Determine the direction of rotation of the worm or worm gear: erect the axis of the worm gear or worm, the height of the right side of the helix is right-handed, and the height of the left side is left-handed.
Determining the steering: Right-handed rotation is the right-hand rule, the active worm is clockwise, and the four fingers of the right hand hold the worm along the steering of the worm, and the thumb points in the opposite direction of the node speed of the worm gear to determine the steering of the worm gear.
If you want to judge the rotation of a gear at hand, you can lay the gear in front of you and see the direction of the teeth. If the left is high and the right is low, it is left-handed. The opposite is right-handed.
Determination of the direction of rotation of the helical gear:
Left and right hand rules: left hand with left hand, right hand with the right thumb and axial coincidence, four fingers pointing in the upward direction of the helical teeth, left hand match is left hand, right hand match is right hand (always the back of the hand is facing yourself).