The main characteristics of the harmonic reducer are elastic deformation and small tooth shape.Therefore, the deformation must be controlled within the range required by the design, and exceeding the control range will cause the failure of the transmission.In power transmission, the control of elastic deformation is more important, and the phenomenon of tooth skipping often occurs, which is also a key factor that the bearing capacity of many harmonic reducer transmission equipment cannot be improved.Once the tooth skipping phenomenon occurs, the transmission device will be damaged quickly if measures are not taken in time.
The essence of the skipping tooth skipping problem is that in a system consisting of a rigid wheel, a flexible wheel and a generator, when an external load is applied, a radial network will be created in the teeth.Rigid wheels, flexible wheels and generators support each other, each subject to a certain amount of deformation.When the relative deformation between the rigid wheel and the flexible wheel exceeds the height of the gear teeth, under the action of the tangential component force, the tooth skipping phenomenon occurs.When the load is large, the violent impact will make a loud noise and damage the teeth.
There are three keys to control morphing.One is to control the load so that it will not be overloaded due to the large bearing capacity of the harmonic drive; one is to strengthen the support; the other is to design the stiffness of the relevant structure to avoid excessive deformation.Due to the complexity of the problem, it is difficult to obtain some simple and general calculation formulas.The following methods and measures can be adopted in a specific design.
1. Lack of rigidity The radial stiffness of the wheel is the key factor causing the teeth to skip.Under a larger load state, a rigid wheel with poor radial stiffness will deform like a flexible wheel, which greatly reduces the bearing capacity.The radial deformation of the rigid wheel can be roughly estimated by referring to the radial deformation of the ring in the elastic force.
2. The support stiffness of the generator to the flexible wheel is also an important factor affecting the phenomenon of tooth skipping.This test shows that when the double contact wave generator is used, since the flexible wheel has only two fulcrums, it is difficult to control the deformation of the flexible wheel after loading, and the jumping phenomenon occurs when the load is small.When four contact wave generators are used, the flexible wheel has four support points, and the support points are close to the action point of the external load, so the bearing capacity is improved.When thin-walled bearing generators are used, the control of the deformation state will be further improved, but due to the limited filling angle of the bearing, the bearing capacity can be greatly improved.Under conditions of large loads, the disk-type wave generator can be used as a generator with great control over the deformation of the flexible wheel.In particular, it is convenient to handle and change design parameters.The bearings used are also standard bearings, so they have good processability.
3. Increasing the wave height within the allowable range is also an important means to solve the phenomenon of tooth skipping.When the phenomenon of tooth skipping occurs, the method of increasing the wave height is also an important means of restoration, and the effect is relatively significant.
4. In the process of design, handling and installation, one-sided deviation will cause skipped teeth.When using a disk generator, special attention should be paid to the symmetry of the eccentric shaft, otherwise it will lead to loading of individual side teeth and lead to skipped teeth.
5. In the structural design, the thickness of the anti-bending ring can also be appropriately increased to control the deformation of the flexible wheel.In addition, reasonable tooth removal and crown correction should also be controlled during the design process.
The above are critical factors that cannot improve the bearing capacity of today's harmonic reduction drive equipment.I hope this device helps you in the future.
