Analysis of the abnormal noise of the KUKA robot reducer

Planning reasons and countermeasures

1. Japan RV reducer internal gear accuracy level planning Japan RV reducer planners often consider economic factors as much as possible to confirm the gear accuracy level negligence accuracy level is the gear noise and backlash mark. The United States Gear Manufacturers Association has conducted a large number of gear studies and confirmed that high-precision grade gears are much less noisy than low-precision grade gears. Therefore, if the conditions are acceptable, the accuracy level of the gear should be improved as much as possible, which can not only reduce transmission errors, but also reduce noise.

2. The internal gear width of the Japan RV reducer is increased when the transmission space of the Japan RV reducer is promised, which can reduce the unit load under constant torque. Lowering tooth deflection reduces noise excitation and then reduces transmission noise. The study of H Opaz in Germany shows that when the torque is constant, the noise curve gradient of small tooth width is higher than that of large tooth width. Increasing the width of the gear together can also increase the bearing capacity of the gear in order to improve the bearing torque of the RV reducer in Japan.

3. The tooth pitch and pressure angle of the internal gear of Japan RV reducer can ensure that there are more gear teeth touching together, and the gear stacking increases, reducing the deflection of a single gear, reducing the transmission noise, and improving the transmission accuracy. The small pressure angle is small because the gear touch angle and the transverse stacking ratio are relatively large, so the working noise is small and the accuracy is high.

4. Japan RV reducer internal gear displacement coefficient selection is correct and reasonable selection of displacement coefficient can not only prevent gear root cutting on the center distance, ensure satisfactory concentric conditions, improve the transmission function and progress of the gear, its bearing capacity and improve the service life of the gear, but also effectively control the backlash, temperature rise and noise. In the closed gear transmission, the main failure mode of the gear with the hard tooth surface hardness of 350HBS is the tooth root fatigue and breakage, and this gear transmission planning is generally carried out according to the tortuousness fatigue strength, and the selection of displacement coefficient should ensure that the meshing teeth have equal flexural strength. For gears with a soft tooth surface hardness of 350HBS, the main failure mode is fatigue pitting, this kind of gear transmission planning is generally carried out according to the touch fatigue intensity, and the selection of displacement coefficient should ensure that the maximum possible touch fatigue strength and fatigue life.

The constraints for the reasonable selection of displacement coefficients are:

(1) Make sure that the gear to be cut does not undercut

(2) To ensure the smoothness and coincidence of gear transmission, it is necessary to be greater than 1, and the general requirement is greater than 1.2

(3) Make sure that the top of the tooth has a certain thickness

(4) When a pair of gears mesh transmission, if the involute of the top of one wheel and the transition curve of the root of the other wheel of teeth touches, because the transition curve is not the involute, the common normal of the two tooth profiles at the contact point can not pass through the fixed node, so the change of the transmission ratio may also make the two wheels stuck, and this transition curve is necessary to prevent when selecting the displacement coefficient.

5. Japan RV reducer internal gear tooth shape trimming and root trimming and tooth top chamfering cut the tooth shape of the tooth top into a slightly convex shape than the correct involute curve. When the tooth surface of the gear is deformed by external force, it can prevent the gear from drying and meshing with it, and can reduce the noise and prolong the life of the gear. It should be noted that excessive trimming is equivalent to the addition of tooth shape errors, which will adversely affect the meshing.

6. Analysis of gear acoustic radiation characteristics: When selecting gears with different structural methods, an acoustic radiation model is established for their specific structure, dynamic analysis is carried out, and the noise of gear transmission system is evaluated in advance. In order to be satisfied according to the different requirements of the user, whether the application site is unmanned, whether it is in the urban interior, whether there are specific requirements for underground buildings, whether there are noise protection or other specific requirements.

7. The working speed of the power source of the Japan RV reducer is indicated according to the experiment of the Japan RV reducer under different speed conditions, and the noise will increase with the input speed of the Japan RV reducer.

8. The experimental study of the structure of the RV reducer box in Japan shows that the selection of cylindrical box is beneficial to shock absorption, and under the same conditions, the noise level of the cylindrical box is 5dB lower than that of other types of boxes on average. The resonance test of the RV reducer case in Japan is found out the resonance orientation, and the appropriate rib plate can improve the rigidity of the box, reduce the oscillation of the box, and complete noise reduction. In the case of multi-stage transmission, the instantaneous transmission ratio is required to change as little as possible to ensure stable transmission, small impact and low oscillation, and low noise.

Analysis of the abnormal noise of the KUKA robot reducer

Analysis of the abnormal noise of the KUKA robot reducer

Reasons for production and countermeasures

1.Japan The internal gear error of the RV reducer affects the gear manufacturing process, and the tooth shape error, base section deviation, tooth direction error and gear ring radial runout error are the main errors that lead to the transmission noise of the planetary Japan RV reducer. It is also a problem point for controlling the transmission power of the planetary Japan RV reducer. Now the tooth shape error and tooth direction error are briefly explained. The noise of gears with small tooth shape error and small tooth surface roughness is 10dB smaller than that of ordinary gears under the same experimental conditions. Under the same experimental conditions, the noise level of gears with small pitch errors is 612dB smaller than that of ordinary gears. However, if there is a pitch error, the effect of the load on the gear noise will be reduced. Tooth direction error will cause the transmission power is not full tooth width transmission, and this or that end face of the steering tooth in the contact area will be increased due to the increase in part of the force, and the deflection of the gear teeth will lead to the improvement of the noise level. However, at high loads, the tooth deformation can partially compensate for the tooth misdirection.

2. The installation of concentricity and dynamic balance installation is not concentric, which will lead to the unbalance of the shafting work, and the noise will be aggravated due to the tooth theory meshing, half of the loose half and half of the tight. The imbalance during the installation of high-precision gear transmission will seriously affect the accuracy of the transmission system.

3. The internal tooth surface hardness of Japan RV reducer follows the development of gear hard tooth surface technology, and its characteristics of large bearing capacity, small size, light weight and high transmission accuracy make its application field increasingly wide. However, in order to obtain the hard tooth surface, the carburizing and hardening selected make the gear deformed, resulting in an increase in the noise of the gear transmission and a shortening of the service life. In order to reduce noise, the tooth flanks need to be finished. At present, in addition to the traditional grinding method, a hard tooth surface scraping method is carried out, and the tooth shape of the active and passive wheels is reduced by correcting the tooth top and the tooth root, or the tooth shape of the active and passive wheels is adjusted to reduce the gear meshing and meshing impact, and then reduce the gear transmission noise.

4. Japan RV reducer system target verification, before installation, the processing accuracy of parts and the selection of parts, complete interchangeability, group selection, single piece selection, etc. will affect the accuracy level of the system after installation, and its noise level is also within the influence range, so after installation, the verification or calibration of the various objectives of the system is very critical to the noise of the control system.

Analysis of the abnormal noise of the KUKA robot reducer

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