Miter Gearbox Common Problem
Helical gears are not entirely helical gears, it should be said that the helical gears are two helical gear meshing way, by their space in the direction of the transmission force to distinguish. Ordinary spur gears enter the meshing at the same time as the teeth, resulting in shock and vibration noise, transmission is not smooth. Helical cylindrical gear drive is superior to straight teeth, and can be close to the center distance for high-speed heavy load. The helical gear reducer is a novel slowdown transmission. The use of optimization, modular combination of advanced design concepts, with a small size, light weight, transmission torque, smooth start, the transmission ratio grading fine, according to user requirements for any connection and a variety of installation location options.
1. The angle between the helical gear and the axis of the helical gear.
The helix angle is characteristic of helical gears and does not exist in spur gears or spur gears. In general, we usually refer to the helix angle of the helical gear, refers to the degree of separation on the cylindrical surface of the helix angle. The greater the helix angle, the greater the degree of overlap, the more conducive to smooth movement and reduce noise, anything is two sides, while increasing the spiral angle brings a lot of advantages, but the work of the axial force is also increased, so The size should depend on the quality of work requirements and processing accuracy, generally take 8-25 if the noise has special requirements, according to the situation to take a larger value.
Helix rotation to determine: First, we will be perpendicular to the gear axis, if the right side of the spiral line for the right-hand; the other hand, the left side of the spiral line for the left.
2. Face and face parameters:
End surface: perpendicular to the plane of the plane of the gear, the parameters on the end of the general increase under the standard t;
Law surface: the vertical plane with the helix, the surface of the parameters of the general plus the standard n.
(1) pitch and modulus: = t = π
(2) pressure angle: the general provisions of the law within the parameters of the standard parameters.
a, the correct engagement conditions: the helix angle must be equal in size, the opposite direction. The surface modulus m and the surface pressure angle are equal.
b, geometric calculation: the calculation of the spur gear can be used directly on the helical gear end face is due to a pair of helical gears in the end plane is equivalent to a pair of spur gears
Advantages and disadvantages
(1) meshing performance: helical cylindrical gear teeth between the meshing process is an excessive process, the force on the teeth is gradually from small to large, and then from large to small; helical gears for high-speed, Heavy load situation.
(2) coincidence degree: increase the degree of coincidence to increase the load capacity of the gear. Thus extending the life of the gear. The degree of coincidence depends mainly on the engagement time, while the helical gears have a long engagement time and a large contact area to reduce the stress. And make the transmission smooth, and increase its economy.
(3) compact: the smallest number of teeth, the more compact structure.
Disadvantages and corrections:
Character gear manufacturing is too much trouble.
The axial component force is detrimental to the gear drive, which increases the friction between the devices and makes the device susceptible to wear or damage. And the shortcomings of the helical gear as long as the gear will produce axial force. And the axial force is caused by the helix angle, the greater the helix angle produced by the greater the axial force. In order not to produce too large axial force of the helical gear, the design generally take = 8 ~ 15.
Helical gears are the most commonly used types of automotive power transmission gears, and are generally required to operate under high-speed reload conditions and require less vibration and noise. In order to improve their dynamic performance at high speed, reduce vibration and noise, tooth profile modification has become a necessary design and process means.
There are two ways to modify the tooth profile of the helical gear
a is oblique correction, that is, the surface of the tooth surface along the tooth contact line. This type of modification in the calculation method and the spur gear is no essential difference, but requires curved surface and involute surface along the contact line tangent, which is difficult to guarantee in the process.
b is straightforward, that is, the curved surface parallel to the tooth direction, in the process to the entire tooth surface can be processed into a smooth surface.Currently the world's actual use of the modification is mostly straightforward. However, since the tooth contact line of the helical gear is inclined, the straightening shape will change the load distribution along the contact line, and even become non-full length contact, and then change the degree of coincidence and tooth load distribution, the traditional gear repair calculation method Failure, the difficulty of its shape design greatly increased
Frequently Asked Questions and Solutions
1, helical gear reducer common problems and reasons:
a. reducer heat and oil spill;
b. Worm wear;
c. drive small helical gear wear;
d. Worm bearing is damaged.
2, helical gear reducer common problem solution
(1) to ensure the quality of assembly
Professional tools are essential to ensure assembly quality. The original parts are usually the best choice for parts and components replacement, when one of the parts of the damage occurred, the general adhere to the principle of pair replacement. When assembling the output shaft, pay attention to the tolerance fit: the hollow shaft is also the object that needs to be protected. If the wear rust or surface fouling occurs, it will affect the later dismantling.
(2) the choice of lubricants and additives
Lubricants and additives are intended to allow the reducer to have a protective film attached to the surface when the gearbox is stopped. When the frequent start of the oil film protection can extend the life of the machine, while protecting the machine in the case of high-speed overload operation. The use of additives can also effectively prevent oil spills, so that the ring lengthen the mission, to maintain soft and flexible. helical gear. Worm gear reducer lubricants generally use 220 # gear oil, the use of additives generally used in the bad environment, such as the larger load, start the frequent instability caused by such phenomena.
(3) the choice of reducer installation location
In the case of permissible position, try not to use vertical installation. Vertical installation can cause the occurrence of oil and other adverse conditions.
(4) the establishment of lubrication maintenance system
"Five principles" is the lubrication maintenance system. First, the person will be regularly checked, so that the responsibility of a clear division of labor; and then the temperature of the strict control, the general control of the heating rate does not exceed 40 degrees, the oil temperature does not exceed 80 degrees; the amount of oil to strictly Reducer to get the correct lubrication, when the quality of oil or noise occurs, etc., should immediately stop using, do maintenance and other work